SPECIFIC ATIONS, TOLERANCES, AND  
OTHER TECHNICAL REQUIREMENTS FOR 
WEIGHING AND MEASURING DEVICES  
 
 
United States  Department of Commerce  
 
Technology  
Administration 
 
National Institute of  Standards and Technology  
 
As adopted by the 1009 9th National Conference on  Weights and Measures 2016201 5 
NIST Handbook44 
20162015 
  
MARKUP COPY  
Agency No. 209.02   
   
 Foreword  
NIST Handbook  44 was first published  in 1949, having been preceded by similar handbooks of various designations 
and in several forms, beginning in 1918.  
NIST Handbook  44 is published in its entirety each year following the Annual Meeting of the National Conference 
on Weights and Measures (NCWM).  The Committee on Specifications and Tolerances of the NCWM developed 
the 2014 Edition 2015 edition  with the assistance of the Office of Weights and Measures Division (WMD (OWM ) of 
the National Institute of Standards and Technology (NIST).  This handbook includes amendments endorsed by the 
98th100th National Conference on Weights and Measures during its Annual Meeting in 20132015.  
 
NIST has a statutory responsibility for “cooperation with the states in securing uniformity of weights and measures laws and methods of inspection.”  In partial fulfillment of this responsibility, NIST is pleased to publish the se 
recommendations of the NCWM.  
This handbook conforms to the concept of primary use of SI (metric) measurements recommended in the Omnibus Trade and Competitiveness Act of 1988 by citing SI units before inch- poundU.S. customary  units where both units 
appe ar together and placing separate sections containing requirements in SI units before corresponding sections 
containing requirements in inch-poundU.S. customary  units.  In some cases, however, trade practice is currently 
restricted to the use of inch -pound U.S. customary  units; therefore, some requirements in this handbook will continue 
to specify only inch- poundU.S. customary  units until the NCWM achieves a broad consensus on the permitted SI 
units.  
 
In accord with NIST policy, the meter/liter spellings are used in this document.  However, the metre /litre spellings 
are acceptable, and are preferred by the NCWM.  
It should be noted that a space has been inserted instead of commas in all numerical values greater than 9999 in this 
document, following a growing practice, originating in tabular work, to use spaces to separate large numbers into 
groups of three digits.  This avoids conflict with the practice in many countries to use the comma as a decimal 
marker.  
 
 
 
  
 
 
 
  
 
 
 
 
 
  
 
 
  You are invited to provide online feedback r egarding this 
document at:   https://www.surveymonkey.com/s/customer-
satisfaction -pub or by e -mail to:  owm@nist.gov.  
 Handbook 44 – 2015 2016  Amendments/Editorial Changes  
 
   Handbook 44 –  2015 2016  Amendments/Editorial Changes  
 
  
 
Committee on Specifications and Tolerances  
of the 99th100th Conference  
 
Brett Gurney, Utah  
Mahesh Albuquerque, Colorado  
Matthew Curran, Florida  
Ivan Hankins, Iowa  
Rachelle Miller, Wisconsin  
Jane Zulkiewicz, Town of Barnstable, Massachusetts  
Luciano Burtini, Measurement Canada, Technical Advisor  
Tina Butcher Clark Cooney , NIST, Technical Advisor  
Rick Harshman, NIST, Technical Advisor  
Darrell Flocken, NCWM, NTEP Speci alist 
Past Chairmen of the Committee  
 
Conference  Chairman   Conference  Chairman  
8-11 L.A. Fischer, NBS   71-7270 F. Gerk , NM D.A. Guensler , CA  
12-28 F.S. Holbrook, NBS   7371-72 K. Butcher, MD F. Gerk , NM  
29-38 J.P. McBride, MA   7374 K. Butcher, MD R. Andersen, NY  
39-42 R.E. Meek, IN   7475 R. Andersen, NY D. Watson, TX  
43-44 J.E. Brenton, CA   7576 D. Watson, TX J. Truex, OH  
45-47 C.L. Jackson, WI   77-7876 C. Carroll, MA J. Truex, OH  
48 T.C. Harris, VA   7977-78 J. Jeffries, FL C. Carroll, MA  
49-50 R.E. Meek, IN   7980 J. Jeffries, FL R. Suiter , NE 
51-52 G.L. Johnson, KY   8081 R. Suiter , NEG. West, NM  
53 H.D. Robinson, ME   82-8381 R. Murdock, NC G. West, NM  
54-55 R. Rebuffo, NE   8482-83 D. Brown, IA R. Murdock, NC  
56-57 D.E. Konsoer , WI  8485 D. Brown, IA M. Hopper, CA  
58 J.C. Mays, FL   8586 M. Hopper, CA G. Shefcheck , OR  
59 T.F. Brink, VT   8687 G. Shefcheck , OR M. Coyne, MA  
60 W.S. Watson, CA   8788 M. Coyne, MA R. Wotthlie , MD  
61 K.J. Simila , OR   8889  R. Wotthlie , MD C. VanBuren , MI 
62 W.E. Czaia , MN   89 90 C. VanBuren , MIJ. Kane, MT  
63 M.L. Kinlaw , NC   9091 J. Kane, MT C. Cooney, OR  
64 J.A. Bird, NJ   9192 C. Cooney, OR M. Sikula , NY  
65 D.A. Guensler , CA   9293 M. Sikula , NY C. Fulmer, SC  
66 G.A. Delano, MT   9394 C. Fulmer, SC T. R. Lucas, OH  
67 F.C. Nagele , MI  9495 T. R. Lucas, OH B. Saum, San Luis 
Obispo Co., CA  
68 L.H. DeGrange , MD   96-9795  S. Giguere, ME B. Saum, San Luis 
Obispo Co., CA  
69 S.A. Colbrook , IL  9896-97 K. Ramsburg, MD S. Giguere, ME  
70 D.A. Guensler , CA   9899 K. Ramsburg, MD B. Gurney, UT  
  Handbook 44 – 2015 2016  Amendments/Editorial Changes  
 
    Handbook 44 –  2015 2016  Amendments/Editorial Changes  
 
  
 
 
2016 15 Amendments  
The following table lists the codes, paragraphs, and pages in which the 1009th National Conference on Weights and 
Measures made amendments.  In the column headed “Action,” changes are noted as “added,” “amended,” “deleted,” or “renumbered.”  Each code, section, or paragraph that has been changed will be noted as “Added 2015” or 
“Amended  2015.”  
SECTION  CODE  S&T  
ITEM 
NO. PARAGRAPH  ACTION  PAGE  
Introduction   BOD  
120-7 A. Source;  
C. Amendments;  Amended  1 
D. Submission of Agenda 
Items – Preamble;  
E. Submission Process;  
F. Procedures;  
G. Criteria for Inclusion on 
the NCWM Committee’s 
Agenda;  
H. Exceptions to Policy for 
Submission of Items to a 
NCWM Committee 
Agenda; Submission of 
“Priority” Items;  
I. Committee Agenda;  
J. Interim Meeting;  
K. Interim Meeting Report;  
L. Classifications for 
Agenda Items;  
M. Comments on Interim 
Reports; and  
N. Annual Meeting  Deleted; remaining 
paragraphs re -
lettered  1 to 3 
1.10.  General Code 310-2 G-UR.4.1. Maintenance 
Equipment  Amended  1-711 
2.20 Scales  320-2 UR.2.4. T.N.3.5. Separate 
Main Elements:  Load 
Transmitting Elements, 
Indicating Elements, Etc.  Amended  2-4940 
2.21.  Belt- Conveyor 
Scales Scale 
Systems  321-1 URA.1.2.(d)  General  Amended  2-6759 
321-2 S.4. Marking Requirements  Amended  2-61 
321-3 N.2.1. Initial Verification  Amended  2-63 
321-4 N.2.3. Minimum Test Load  Amended  2-64 
321-5 N.3.1.1. Determination of 
Zero Amended  2-65 
321-6 UR.1.2. Conveyor 
Installation  Amended  2-67 Handbook 44 – 2015 2016  Amendments/Editorial Changes  
 
 321-7 UR.3 . Maintenance 
Requirements – Scale and 
Conveyor Maintenance  Amended  2-69 to  
2-71 
2.25.  Weigh -In-Motion 
Vehicle Scales for 
Law Enforcement –  
Tentative Code  320-4 Section 2.25. Weigh -In-
Motion Vehicle Scales for 
Law Enforcement –  
Tentative Code  Tentative Code 
Added to 
Handbook 2-109 to  
2-118 
3.30.  Liquid Measuring 
Devices  330-12 S.1.6.7. Table S.2.2. 
Categories of Device and 
Methods of Sealing  Amended  3-1113 
3.40.  Electric Vehicle 
Fueling Systems –  
Tentative Code  360-5 UR.3.3. Section 3.40. 
Electric Vehicle Fueling 
Systems – Tentative Code  Tentative Code 
Added to 
Handbook Amended  3-23145 to  
3-24164 
5.54.  Taximeters  330-3354-
1 N.4.2.4. S.1.1.1. Recording 
Elements  Amended  3-195-27 
  
330-
5A354-3 U.RS.1.3.3.(c)(1). 
Passenger Indications  Added Amended  3-245-27 
to 
5-28 
  U.RS.1.3.3. and 1. 
Additional 
Information UR.3. 3.(c)(2)  Added Amended  3-245-28 
  S.1.5.3.3.2. Fare and Extras 
Charges  Added  3-505-28 
354-4 S.1.8. Protection of 
Indications  Amended  5-29 
354-5 S.1.9. Recorded 
Representation  Amended  5-29 
5.55.  Timing Devices  360-5 A.1. General  Amended  5-37 
S.1.1.1. General  Amended  5-37 
S.1.1.5. Operation of In -
Service Indicator Light  Amended  5-37 
S.1.4. Recorded 
Representations  Amended  5-38 
S.1.4.1. Recorded 
Representations, Electric 
Vehicle Supply Equipment  
Timing Devices  Added  5-38 
S.1.4.1.1. Duplicate 
Receipts  Added  5-38 
S.1.4.2. Recorded 
Representations, All Other 
Timing Devices  Added  5-39 
S.3. Interference  Added  5-39 
S.4. Provisions for Sealing  Added  5-39 
S.5. Power Interruption  Added  5-39 
S.5.1. Power Interruption  Added  5-39  Handbook 44 –  2015 2016  Amendments/Editorial Changes  
 
 S.5.2. User Information  Added  5-39 
5.55.  
 (cont.)  Timing Devices  360-5 N.3. Interference Tests, 
EVSE  Added  5-40 
5.55.  
(cont.)  Timing Devices  360-5 T.1.3. On Parking Meters 
and Other Timing Devices 
Used to Assess Charges for 
Parking  Amended  5-41 
Table T.1.3. Maintenance 
and Acceptance Tolerances 
for Parking Meters and 
Other Timing Devices Used 
to Assess Charges for 
Parking  Amended  5-41 
UR.1. Statement of Rates  Amended  5-41 
Appendix D  Definitions  321-8 Weigh -Belt System  Added  D-28 
360-3 Point -of-Sale-System  Amended  D-21 
  Handbook 44 – 2015 2016  Amendments/Editorial Changes  
 
  Handbook 44 – 2015 2016  Amendments/Editorial Changes  
 
 20152016 Editorial Changes  
SECTION  CODE  PARAGRAPH  ACTION  PAGE  
AllIntroduction   Form 15 The references to “inch -pound” 
have been changed to “U.S. 
customary.” Updated Form  4 
2.2021 . Scales Belt-
Conveyor Scale 
Systems  S.6UR.3 .1. Deleted note referring to N.1.3.3. 
and T.N.3.1.; the note is no longer 
necessary. Renumber to UR.3.  2-2169  
2.213.32 . Belt-Conveyor 
Scale Systems LPG and 
Anhydrous 
Liquid -
Measuring 
Devices  URS.1.2.2.  Deleted the second sentence referencing the orientation of the 
conveyor, which was repeated in 
paragraph UR.1.2.(h). Reformatted 
for ease of use  2-673-48 
5.54.  Taximeter  N.1.3.2. Tire Pressure  Replaced “odometer” with 
“taximeter”  5-32 
5.50. Appendix 
C Fabric -
Measuring Devices Units of 
Mass Not 
Greater than 
Pounds and 
Kilograms  S.1 avdp. pound . Units  Corrected the fraction “1/7 yd” to 
“1/8 yd.”  Corrected reference to 
metric units.  Restructured for 
clarity. Corrected figure 453 
592.37. 37 5-5C-14 
Appendix D  Definitions  Grain sample  Added quantity to “bulk quantity  
grain”  D-13 
Automatic hopper 
scale  Removed term  D-6 
  
  Handbook 44 –  20152016  Markup Copy 
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  Handbook 44 2015 2016  
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Agency No. 209.02  
 Appendix A.  Fundamental Considerations Associated with the 
Enforcement of Handbook  44 Codes  
 
 
1. Uniformity of Requirements  
 
1.1. National Conference Codes.  – Weights and measures jurisdictions are urged to promulgate and adhere to the 
National Conference codes, to the end that uniform requirements may be in force throughout the country.  This 
action is recommended even though a particular jurisdiction does n ot wholly agree with every detail of the National 
Conference codes.  Uniformity of specifications and tolerances is an important factor in the manufacture of 
commercial equipment.  Deviations from standard designs to meet the special demands of individual weights and 
measures jurisdictions are expensive, and any increase in costs of manufacture is, of course, passed on to the purchaser of equipment .  On the other hand, if designs can be standardized by the manufacturer to conform to a 
single set of technica l requirements, production costs can be kept down, to the ultimate advantage of the general 
public.  Moreover, it seems entirely logical that equipment that is suitable for commercial use in the “specification” states should be equally suitable for such us e in other states.  
 
Another consideration supporting the recommendation for uniformity of requirements among weights and measures 
jurisdictions is the cumulative and regenerative effect of the widespread enforcement of a single standard of design 
and perfo rmance.  The enforcement effort in each jurisdiction can then reinforce the enforcement effort in all other 
jurisdictions.  More effective regulatory control can be realized with less individual effort under a system of uniform 
requirements than under a system in which even minor deviations from standard practice are introduced by 
independent state action . 
 
Since the National Conference codes represent the majority opinion of a large and representative group of 
experienced regulatory officials, and since th ese codes are recognized by equipment manufacturers as their basic 
guide in the design and construction of commercial weighing and measuring equipment, the acceptance and 
promulgation of these codes by each state are strongly recommended.  
 1.2. Form of Pro mulgation.  – A convenient and very effective form of promulgation already successfully used in 
a considerable number of states is promulgation  by citation of National Institute  of Standards and Technology 
Handbook  44.  It is especially helpful when the cit ation  is so made that, as amendments are adopted from time to 
time by the National Conference on Weights and Measures, these automatically go into effect in the state regulatory authority.  For example, the following form of promulgation has been used succ essfully and is recommended for 
consideration:  
 
The specifications, tolerances, and other technical requirements for weighing and measuring devices as 
recommended by the National Conference on Weights and Measures and published in the National Institute of  
Standards and Technology Handbook  44, “Specifications, Tolerances, and Other Technical Requirements for 
Weighing and Measuring Devices,” and supplements thereto or revisions thereof, shall apply to commercial 
weighing and measuring devices in the state.  
 
In some states, it is preferred to base technical requirements upon specific action  of the state legislature rather than 
upon an act of promulgation by a state officer.  The advantages cited above may be obtained and may yet be 
surrounded by adequate safeguards to insure proper freedom of action by the state enforcing officer if the legislature 
adopts the National Conference requirements by language somewhat as follows:  
 
The specifications, tolerances, and other technical requirements for weighing and measu ring devices as 
recommended by the National Conference on Weights and Measures shall be the specifications, tolerances, and 
other technical requirements for weighing and measuring devices of the state except insofar as specifically 
modified, amended, or re jected by a regulation issued by the state (insert title of enforcing officer).  
 Handbook 44 –  20152016  Markup Copy 
 Agency No. 209.02  
 
 2. Tolerances for Commercial Equipment  
 
2.1. Acceptance and Maintenance Tolerances . – The official tolerances prescribed by a weights and measures 
jurisdiction for commercial equipment are the limits of inaccuracy officially permissible within that jurisdiction.  It 
is recognized that errorless  value or performance of mechanical equipment is unattainable.  Tolerances are 
established, therefore, to fix the range of inaccuracy wi thin which equipment will be officially approved for 
commercial use.  In the case of classes of equipment on which the magnitude of the errors of value or performance 
may be expected to change as a result of use, two sets of tolerances are established:  acceptance tolerances and 
maintenance tolerances.  
 Acceptance tolerances are applied to new or newly reconditioned or adjusted equipment, and are smaller than 
(usually one -half of) the maintenance tolerances.  Maintenance tolerances thus provide an additional range of 
inaccuracy within which equipment will be approved on subsequent tests, permitting a limited amount of 
deterioration before the equipment will be officially rejected for inaccuracy and before reconditioning or adjustment 
will be require d.  In effect, there is assured a reasonable period of use for equipment after it is placed in service 
before reconditioning will be officially required.  The foregoing comments do not apply, of course, when only a 
single set of tolerance values is establi shed, as is the case with equipment such as glass milk bottles and graduates, 
which maintain their original accuracy regardless of use, and measure -containers, which are used only once.  
 
2.2. Theory of Tolerances.  – Tolerance values are so fixed that the p ermissible errors are sufficiently small that 
there is no serious injury to either the buyer or the seller of commodities, yet not so small as to make manufacturing 
or maintenance costs of equipment disproportionately high.  Obviously, the manufacturer mus t know what 
tolerances his equipment is required to meet, so that he can manufacture economically.  His equipment must be good enough to satisfy commercial needs, but should not be subject to such stringent tolerance values as to make it 
unreasonably costl y, complicated, or delicate.  
 
2.3. Tolerances and Adjustments.  – Tolerances are primarily accuracy criteria for use by the regulatory official.  
However, when equipment is being adjusted for accuracy, either initially or following repair or official reject ion, the 
objective should be to adjust as closely as practicable to zero error.  Equipment owners should not take advantage of 
tolerances by deliberately adjusting their equipment to have a value, or to give performance, at or close to the 
tolerance limit.   Nor should the repair or service personnel bring equipment merely within tolerance range when it is 
possible to adjust closer to zero error.
1 
 
3. Testing Apparatus  
 
3.1. Adequacy.2 – Tests can be made properly only if, among other things, adequate testing apparatus is available.  
Testing apparatus may be considered adequate only when it is properly designed for its intended use, when it is so 
constructed that it will retain its char acteristics for a reasonable period under conditions of normal use, when it is 
available in denominations appropriate for a proper determination of the value or performance of the commercial 
equipment under test, and when it is accurately calibrated.  
 
3.2. Tolerances for Standards.  – Except for work of relatively high precision, it is recommended that the 
accuracy of standards used in testing commercial weighing and measuring equipment be established and maintained 
                                                           
1 See General Code, Section  1.10.; User Requirement  G-UR.4.3. Use of Adjustments.  
 
2 Recommendations regarding the specifications and tolerances for suitable field standards may be obtained from 
the Office of Weights and Measures  Division  of the National Institute of Standards and Technology.  Standards 
will meet the specifications of the National Institute of Standards and Technology Handbook  105- Series 
standards (or other suitable and designated standards).  This section shall not preclude the use of additional field 
standards and/or equipment, as approved by the Director, for uniform evaluation of device performance.   Handbook 44 2015 2016  
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Agency No. 209.02  
 so that the use of corrections is not nece ssary.  When the standard is used without correction, its combined error and 
uncertainty must be less than one -third of the applicable device tolerance.  
 
Device testing is complicated to some degree when corrections to standards are applied.  When using a correction 
for a standard, the uncertainty associated with the corrected value must be less than one- third of the applicable 
device tolerance.  The reason for this requirement is to give the device being tested as nearly as practicable the full benefit of its own tolerance.  
 3.3. Accuracy of Standards.  – Prior to the official use of testing apparatus, its accuracy should invariably be 
verified.  Field standards should be calibrated as often as circumstances require.  By their nature, metal volumetric 
field standards are more susceptible to damage in handling than are standards of some other types.  A field standard 
should be calibrated whenever damage is known or suspected to have occurred or significant repairs have been 
made.  In addition, field standards,  particularly volumetric standards, should be calibrated with sufficient frequency 
to affirm their continued accuracy, so that the official may always be in an unassailable position with respect to the 
accuracy of his testing apparatus.  Secondary field st andards, such as special fabric testing tapes, should be verified 
much more frequently than such basic standards as steel tapes or volumetric provers to demonstrate their constancy 
of value or performance.  
 Accurate and dependable results cannot be obtained with faulty or inadequate field standards.  If either the service 
person or official is poorly equipped, their results cannot be expected to check consistently.  Disagreements can be avoided and the servicing of commercial equipment can be expedited and improved if service persons and officials 
give equal attention to the adequacy and maintenance of their testing apparatus.  
 
4. Inspection of Commercial Equipment  
 
4.1. Inspection Versus Testing.  – A distinction may be made between the inspection and the testing of 
commercial equipment that should be useful in differentiating between the two principal groups of official 
requirements; i.e.,  specifications and performance requirements.  Although the term inspection is frequently loosely 
used to include everything that the official has to do in connection with commercial equipment, it is useful to limit 
the scope of that term primarily to examinations made to determine compliance with design, maintena nce, and user 
requirements.  The term testing may then be limited to those operations carried out to determine the accuracy of 
value or performance of the equipment under examination by comparison with the actual physical standards of the 
official.  These two terms will be used herein in the limited senses defined.  
 
4.2. Necessity for Inspection.  – It is not enough merely to determine that the errors of equipment do not exceed 
the appropriate tolerances.  Specification and user requirements are as important  as tolerance requirements and 
should be enforced.  Inspection is particularly important, and should be carried out with unusual thoroughness 
whenever the official examines a type of equipment not previously encountered.  
 
This is the way the official learn s whether or not the design and construction of the device conform to the 
specification requirements.  But even a device of a type with which the official is thoroughly familiar and that he has 
previously found to meet specification requirements should not be accepted entirely on faith.  Some part may have 
become damaged, or some detail of design may have been changed by the manufacturer, or the owner or operator may have removed an essential element or made an objectionable addition.  Such conditions may b e learned only by 
inspection.  Some degree of inspection is therefore an essential part of the official examination of every piece of 
weighing or measuring equipment.  
 4.3. Specification Requirements.  – A thorough knowledge by the official of the specification requirements is a 
prerequisite to competent inspection of equipment.  The inexperienced official should have his specifications before him when making an inspection, and should check the requirements one by one against the equipment itself.  
Otherwise  some important requirement may be overlooked.  As experience is gained, the official will become 
progressively less dependent on the handbook, until finally observance of faulty conditions becomes almost 
automatic and the time and effort required to do th e inspecting are reduced to a minimum.  The printed 
specifications, however, should always be available for reference to refresh the official’s memory or to be displayed 
to support his decisions, and they are an essential item of his kit.  
 Handbook 44 –  20152016  Markup Copy 
 Agency No. 209.02  
 
 Specification re quirements for a particular class of equipment are not all to be found in the separate code for that 
class.  The requirements of the General Code apply, in general, to all classes of equipment, and these must always be 
considered in combination with the re quirements of the appropriate separate code to arrive at the total of the 
requirements applicable to a piece of commercial equipment.  
 
4.4. General Considerations.  – The simpler the commercial device, the fewer are the specification requirements 
affecting it, and the more easily and quickly can adequate inspection be made.  As mechanical complexity increases, 
however, inspection becomes increasingly important and more time consuming, because the opportunities for the existence of faulty conditions are multiplied.  It is on the relatively complex device, too, that the official must be on 
the alert to discover any modification that may have been made by an operator that might adversely affect the proper 
functioning of the device.  
 
It is essential for the offic ials to familiarize themselves with the design and operating characteristics of the devices 
that he inspects and tests.  Such knowledge can be obtained from the catalogs and advertising literature of device 
manufacturers, from trained service persons and p lant engineers, from observation of the operations performed by 
service persons when reconditioning equipment in the field, and from a study of the devices themselves.  
 Inspection should include any auxiliary equipment and general conditions external to the device that may affect its 
performance characteristics.  In order to prolong the life of the equipment and forestall rejection, inspection should 
also include observation of the general maintenance of the device and of the proper functioning of all requi red 
elements.  The official should look for worn or weakened mechanical parts, leaks in volumetric equipment, or 
elements in need of cleaning.  
 
4.5. Misuse of Equipment. –  Inspection, coupled with judicious inquiry, will sometimes disclose that equipment 
is being improperly used, either through ignorance of the proper method of operation or because some other method 
is preferred by the operator.  Equipment should be operated only in the manner that is obviously indicated by its construction or that is indic ated by instructions on the equipment, and operation in any other manner should be 
prohibited.  
 
4.6. Recommendations.  – A comprehensive knowledge of each installation will enable the official to make 
constructive recommendations to the equipment owner regarding proper maintenance of his weighing and measuring 
devices and the suitability of his equipment for the purposes for which it is being used or for which it is proposed 
that it be used.  Such recommendations are always in order and may be very helpful t o an owner.  The official will, 
of course, carefully avoid partiality toward or against equipment of specific makes, and will confine his recommendations to points upon which he is qualified, by knowledge and experience, to make suggestions of 
practical merit.  
 
4.7. Accurate and Correct Equipment.  – Finally, the weights and measures official is reminded that commercial 
equipment may be accurate without being correct.  A piece of equipment is accurate when its performance or value (that is, its indications, its deliveries, its recorded representations, or its capacity or actual value, etc., as determined 
by tests made with suitable standards) conforms to the standard within the applicable tolerances and other 
performance requirements.  Equipment that fails so  to conform is inaccurate.  A piece of equipment is correct when, 
in addition to being accurate, it meets all applicable specification requirements.  Equipment that fails to meet any of 
the requirements for correct equipment is incorrect.  Only equipment t hat is correct should be sealed and approved 
for commercial use.
3 
 
5. Correction of Commercial Equipment  
 5.1. Adjustable Elements.  – Many types of weighing and measuring instruments are not susceptible to 
adjustment for accuracy by means of adjustable elements.  Linear measures, liquid measures, graduates, 
                                                           
3 See Section  1.10. General Code and Appendix  D. Definitions.   Handbook 44 2015 2016  
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Agency No. 209.02  
 measure- containers, milk and lubricating -oil bottles, farm milk tanks, dry mea sures, and some of the more simple 
types of scales are in this category.  Other types (for example, taximeters and odometers and some metering devices) may be adjusted in the field, but only by changing certain parts such as gears in gear trains.  
 
Some typ es, of which fabric -measuring devices and cordage- measuring devices are examples, are not intended to be 
adjusted in the field and require reconditioning in shop or factory if inaccurate.  Liquid -measuring devices and most 
scales are equipped with adjustab le elements, and some vehicle -tank compartments have adjustable indicators.  Field 
adjustments may readily be made on such equipment.  In the discussion that follows, the principles pointed out and the recommendations made apply to adjustments on any commercial equipment, by whatever means accomplished.  
 
5.2. When Corrections Should Be Made.  – One of the primary duties of a weights and measures official is to 
determine whether equipment is suitable for commercial use.  If a device conforms to all legal requ irements, the 
official “marks” or “seals” it to indicate approval.  If it does not conform to all official requirements, the official is 
required to take action to ensure that the device is corrected within a reasonable period of time.  Devices with 
perfor mance errors that could result in serious economic injury to either party in a transaction should be prohibited 
from use immediately and not allowed to be returned to service until necessary corrections have been made.  The 
official should consider the mos t appropriate action, based on all available information and economic factors.  
 Some officials contend that it is justifiable for the official to make minor corrections and adjustments if there is no 
service agency nearby or if the owner or operator depend s on this single device and would be “out of business” if the 
use of the device were prohibited until repairs could be made. Before adjustments are made at the request of the 
owner or the owner’s representative, the official should be confident that the pr oblem is not due to faulty installation 
or a defective part, and that the adjustment will correct the problem.  The official should never undertake major 
repairs, or even minor corrections, if services of commercial agencies are readily available.  The off icial should 
always be mindful of conflicts of interest before attempting to perform any services other than normal device 
examination and testing duties.  
(Amended 1995)  
 
5.3. Gauging.  – In the majority of cases, when the weights and measures official tests commercial equipment, he 
is verifying the accuracy of a value or the accuracy of the performance as previously established either by himself or 
by someone else.  There are times, how ever, when the test of the official is the initial test on the basis of which the 
calibration of the device is first determined or its performance first established.  The most common example of such 
gauging is in connection with vehicle tanks the compartme nts of which are used as measures.  Frequently the official 
makes the first determination on the capacities of the compartments of a vehicle tank, and his test results are used to 
determine the proper settings of the compartment indicators for the exact co mpartment capacities desired.  
Adjustments of the position of an indicator under these circumstances are clearly not the kind of adjustments discussed in the preceding paragraph.  
 
6.  Rejection of Commercial Equipment  
 6.1. Rejection and Condemnation. – The Uniform Weights and Measures Law contains a provision stating that 
the director shall reject and order to be corrected such physical weights and measures or devices found to be incorrect.  Weights and measures and devices that have been rejected, may be seized if not corrected within a 
reasonable time or if used or disposed of in a manner not specifically authorized.  The director shall remove from 
service and may seize weights and measures found to be incorrect that are not capable of being made correct.  
 
These broad powers should be used by the official with discretion.  The director should always keep in mind the 
property rights of an equipment owner, and cooperate in working out arrangements whereby an owner can realize at 
least something from equipmen t that has been rejected.  In cases of doubt, the official should initially reject rather 
than condemn outright.  Destruction and confiscation of equipment are harsh procedures.  Power to seize and 
destroy is necessary for adequate control of extreme situations, but seizure and destruction should be resorted to 
only when clearly justified.  
 On the other hand, rejection is clearly inappropriate for many items of measuring equipment.  This is true for most 
linear measures, many liquid and dry measures, gradua tes, measure- containers, milk bottles, lubricating -oil bottles, Handbook 44 –  20152016  Markup Copy 
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 and some scales.  When such equipment is “incorrect,” it is either impractical or impossible to adjust or repair it, and 
the official has no alternative to outright condemnation.  When only a few such items are involved, immediate 
destruction or confiscation is probably the best procedure.  If a considerable number of items are involved (as, for 
example, a stock of measures in the hands of a dealer or a large shipment of bottles), return of these to the 
manufacturer for credit or replacement should ordinarily be permitted provided that the official is assured that they 
will not get into commercial use.  In rare instances, confiscation and destruction are justified as a method of control 
when les s harsh methods have failed.  
 
In the case of incorrect mechanisms such as fabric- measuring devices, taximeters, liquid -measuring devices, and 
most scales, repair of the equipment is usually possible, so rejection is the customary procedure.  Seizure may occasionally be justified, but in the large majority of instances this should be unnecessary.  Even in the case of 
worn -out equipment, some salvage is usually possible, and this should be permitted under proper controls.  
(Amended 1995)  
 
7. Tagging of Equip ment  
 
7.1. Rejected and Condemned.  – It will ordinarily be practicable to tag or mark as rejected each item of 
equipment found to be incorrect and considered susceptible of proper reconditioning.  However, it can be considered justifiable not to mark as re jected incorrect devices capable of meeting acceptable performance requirements if they 
are to be allowed to remain in service for a reasonable time until minor problems are corrected since marks of 
rejection may tend to be misleading about a device’s abil ity to produce accurate measurements during the correction 
period.  The tagging of equipment as condemned, or with a similar label to indicate that it is permanently out of service, is not recommended if there is any other way in which the equipment can definitely be put out of service.  
Equipment that cannot successfully be repaired should be dismantled, removed from the premises, or confiscated by 
the official rather than merely being tagged as “condemned.” 
(Amended 1995)  
 
7.2. Nonsealed and Noncommercial . – Rejection is not appropriate if measuring equipment cannot be tested by 
the official at the time of his regular visit– for example, when there is no gasoline in the supply tank of a 
gasoline -dispensing device.  Some officials affix to such equipment a n onsealed tag stating that the device has not 
been tested and sealed and that it must not be used commercially until it has been officially tested and approved.  
This is recommended whenever considerable time will elapse before the device can be tested.  
 Where the official finds in the same establishment, equipment that is in commercial use and also equipment suitable 
for commercial use that is not presently in service, but which may be put into service at some future time, he may treat the latter equipment in any of the following ways:  
 
(a) Test and approve the same as commercial equipment in use.  
 
(b) Refrain from testing it and remove it from the premises to preclude its use for commercial purposes.  
 
(c) Mark the equipment nonsealed.  
 Where the official finds commercial equipment and noncommercial equipment installed or used in close proximity, he may treat the noncommercial equipment in any of the following ways:  
 
(a) Test and approve the same as commercial equipment.  
 (b) Physically separate the two gro ups of equipment so that misuse of the noncommercial equipment will be 
prevented.  
 (c) Tag it to show that it has not been officially tested and is not to be used commercially.  
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 8. Records of Equipment  
 
8.1.  The official will be well advised to keep caref ul records of equipment that is rejected, so that he may follow 
up to insure that the necessary repairs have been made.  As soon as practicable following completion of repairs, the 
equipment should be retested.  Complete records should also be kept of equi pment that has been tagged as nonsealed 
or noncommercial.  Such records may be invaluable should it subsequently become necessary to take disciplinary 
steps because of improper use of such equipment.  
 
9. Sealing of Equipment  
 
9.1. Types of Seals and Their Locations.  – Most weights and measures jurisdictions require that all equipment 
officially approved for commercial use (with certain exceptions to be pointed out later) be suitably marked or sealed to show approval.  This is done primarily for the benefit of the public to show that such equipment has been officially examined and approved.  The seal of approval should be as conspicuous as circumstances permit and 
should be of such a character and so applied that it will be reasonably permanent.  Uniformity o f position of the seal 
on similar types of equipment is also desirable as a further aid to the public.  
 
The official will need more than one form of seal to meet the requirements of different kinds of equipment.  Good 
quality, weather -resistant, water -adhe sive, or pressure -sensitive seals or decalcomania seals are recommended for 
fabric -measuring devices, liquid -measuring devices, taximeters, and most scales, because of their permanence and 
good appearance.  Steel stamps are most suitable for liquid and dry  measures, for some types of linear measures, and 
for weights.  An etched seal, applied with suitable etching ink, is excellent for steel tapes, and greatly preferable to a 
seal applied with a steel stamp.  The only practicable seal for a graduate is one m arked with a diamond or carbide 
pencil, or one etched with glass -marking ink.  For a vehicle tank, the official may wish to devise a relatively large 
seal, perhaps of metal, with provision for stamping data relative to compartment capacities, the whole to be welded 
or otherwise permanently attached to the shell of the tank.  In general, the lead -and-wire seal is not suitable as an 
approval seal.  
 
9.2. Exceptions.  – Commercial equipment such as measure -containers, milk bottles, and lubricating -oil bottles are 
not tested individually because of the time element involved.  Because manufacturing processes for these items are 
closely controlled, an essentially uniform product is produced by each manufacturer.  The official normally tests 
samples of these items prior to their sale within his jurisdiction and subsequently makes spot checks by testing 
samples selected at random from new stocks.  
 
Another exception to the general rule for sealing approved equipment is found in certain very small weights whose 
size pr ecludes satisfactory stamping with a steel die.  
 
10. Rounding Off Numerical Values  
 
10.1.  Definition.  – To round off or round a numerical value is to change the value of recorded digits to some other 
value considered more desirable for the purpose at hand by dropping or changing certain figures.  For example, if a 
computed, observed, or accumulated value is 4738, this can be rounded off to the nearest thousand, hundred, or ten, 
as desired.  Such rounded -off values would be, respectively, 5000, 4700, and 4740.  Similarly, a value such as 
47.382 can be rounded off to two decimal places, to one decimal place, or to the units place.  The rounded -off 
figures in this example would be, respectively, 47.38, 47.4, and 47. 
 
10.2.  General Rules.  – The general rules for  rounding off may be stated briefly as follows:  
 
(a) When the figure next beyond the last figure or place to be retained is less than  5, the figure in the last place 
retained is to be kept unchanged.  When rounding off 4738 to the nearest hundred, it is noted that the 
figure  3 (next beyond the last figure to be retained) is less than  5.  Thus the rounded -off value would 
be 4700.  Likewise, 47.382 rounded to two decimal places becomes  47.38.  
 
(b) When the figure next beyond the last figure or place to be retained is  greater than  5, the figure in the last 
place retained is to be increased by  1.  When rounding off 4738 to the nearest thousand, it is noted that the Handbook 44 –  20152016  Markup Copy 
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 figure  7 (next beyond the last figure to be retained) is greater than 5.  Thus the rounded -off value would 
be 5000.  Likewise, 47.382 rounded to one decimal place becomes  47.4.  
 
(c) When the figure next beyond the last figure to be retained is  5 followed by any figures other than zero(s), 
treat as in (b) above; that is, the figure in the last place retained is to be increased by  1.  When rounding 
off 4501 to the nearest thousand, 1 is added to the thousands figure and the result becomes  5000.  
 
(d) When the figure next beyond the last figure to be retained is  5 and there are no figures, or only zeros, 
beyond this  5, the  figure in the last place to be retained is to be left unchanged if it is even (0, 2, 4, 6, or  8) 
and is to be increased by  1 if it is odd (1, 3, 5, 7, or  9).  This is the odd and even rule, and may be stated as 
follows:  “If odd, then add.”  Thus, rounding off to the first decimal place, 47.25 would become 47.2 and 47.15 would become 47.2.  Also, rounded to the nearest thousand, 4500 would become 4000 and 1500 
would become  2000.  
 It is important to remember that, when there are two or more figures to the right of the place where the last 
significant figure of the final result is to be, the entire series of such figures must be rounded off in one step and not 
in two or more successive rounding steps.  [Expressed differently, when two or more such figures ar e involved, 
these are not to be rounded off individually, but are to be rounded off as a group.]  Thus, when rounding off  47.3499 
to the first decimal place, the result becomes  47.3.  In arriving at this result, the figures  “499” are treated as a group.  
Since the  4 next beyond the last figure to be retained is less than  5, the  “499” is dropped (see subparagraph  (a) 
above).  It would be incorrect to round off these figures successively to the left so that  47.3499 would 
become 47.350 and then  47.35 and then  47.4.  
 10.3.  Rules for Reading of Indications.  – An important aspect of rounding off values is the application of these 
rules to the reading of indications of an indicator -and-graduated -scale combination (where the majority of the 
indications may be expect ed to lie somewhere between two graduations) if it is desired to read or record values only 
to the nearest graduation.  Consider a vertical graduated scale and an indicator.  Obviously, if the indicator is 
between two graduations but is closer to one gradu ation than it is to the other adjacent graduation, the value of the 
closer graduation is the one to be read or recorded.  
 In the case where, as nearly as can be determined, the indicator is midway between two graduations, the 
odd-and-even rule is invoked, and the value to be read or recorded is that of the graduation whose value is even.  For 
example, if the indicator lies exactly midway between two graduations having values of  471 and 472, respectively, 
the indication should be read or recorded as  472, thi s being an even value.  If midway between graduations having 
values of  474 and 475, the even value  474 should be read or recorded.  Similarly, if the two graduations involved 
had values of  470 and 475, the even value of  470 should be read or recorded.  
 
A special case not covered by the foregoing paragraph is that of a graduated scale in which successive graduations 
are numbered by twos, all graduations thus having even values; for example, 470, 472, 474, etc.  When, in this case, an indication lies midway b etween two graduations, the recommended procedure is to depart from the practice of 
reading or recording only to the value of the nearest graduation and to read or record the intermediate odd value.  
For example, an indication midway between  470 and 472 sh ould be read as  471. 
 
10.4.  Rules for Common Fractions . – When applying the rounding -off rules to common fractions, the principles 
are to be applied to the numerators of the fractions that have, if necessary, been reduced to a common denominator.  
The principle of  “5s” is changed to the one -half principle; that is, add if more than one -half, drop if less than 
one-half, and apply the odd- and even rule if exactly one -half. 
 
For example, a series of values might be 1
1/32, 12/32, 13/32, 14/32, 15/32, 16/32, 17/32, 18/32, 19/32.  Assume that these values 
are to be rounded off to the nearest eighth  (4/32).  Then,  
 
11/32 becomes 1.  (1/32 is less than half of 4/32 and accordingly is dropped.)  
 
12/32 becomes 1.  (2/32 is exactly one -half of 4/32; it is dropped becau se it is rounded (down) to the “even” eighth, 
which in this instance is  0/8.) 
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 13/32 becomes 14/32 or 11/8.  (3/32 is more than half of 4/32, and accordingly is rounded “up” to 4/32 or 1/8). 
 1
4/32 remains unchanged, being an exact eighth (11/8). 
 
15/32 becomes 14/32 or 11/8.  (5/32 is 1/32 more than an exact 1/8; 1/32 is less than half of 4/32 and accordingly is 
dropped.)  
 1
6/32 becomes 12/8 or 1¼.  (6/32 is 2/32 more than an exact 1/8; 2/32 is exactly one -half of 4/32, and the final fraction is 
rounded  (up) to the “even” eighth, which in this instance is  2/8.) 
 1
7/32 becomes 12/8 or 1¼.  (7/32 is 3/32 more than an exact 1/8; 3/32 is more than one -half of 4/32 and accordingly the 
final fraction is rounded (up) to 2/8 or ¼.) 
 1
8/32 remains unchanged, being an exact eighth (12/8 or 1¼.)  
 
19/32 becomes 12/8 or 1¼.  (9/32 is 1/32 more than an exact 1/8; 1/32 is less than half of 4/32 and accordingly is dropped.)  
 
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Appendix B.  Units and Systems of Measurement Their Origin, 
Development, and Present Status  
 
1. Introduction 
 
The National Institute of Standards and Technology (NIST) (formerly the National Bureau of Standards) was established by Act of Congress in 1901 to serve as a national scientific laboratory in the physical sciences, and to 
provide fundamental measurement standards for science an d industry.  In carrying out these related functions the 
Institute conducts research and development in many fields of physics, mathematics, chemistry, and engineering.  At 
the time of its founding, the Institute had custody of two primary standards –  the meter bar for length and the 
kilogram cylinder for mass.  With the phenomenal growth of science and technology over the past century, the 
Institute has become a major research institution concerned not only with everyday weights and measures, but also 
with hundreds of other scientific and engineering standards that are necessary to the industrial progress of the nation.  
Nevertheless, the country still looks to NIST for information on the units of measurement, particularly their definitions and equivalents.  
 The subject of measurement systems and units can be treated from several different standpoints.  Scientists and 
engineers are interested in the methods by which precision measurements are made.  State weights and measures 
officials are concerned with law s and regulations that assure equity in the marketplace, protect public health and 
safety, and with methods for verifying commercial weighing and measuring devices.  But a vastly larger group of 
people is interested in some general knowledge of the origin and development of measurement systems, of the 
present status of units and standards, and of miscellaneous facts that will be useful in everyday life.  This material 
has been prepared to supply that information on measurement systems and units that experie nce has shown to be the 
common subject of inquiry.  
 
2. Units and Systems of Measurement  
 The expression “weights and measures” is often used to refer to measurements of length, mass, and capacity or 
volume, thus excluding such quantities as electrical and tim e measurements and thermometry.  This section on units 
and measurement systems presents some fundamental information to clarify the concepts of this subject and to 
eliminate erroneous and misleading use of terms.  
 It is essential that the distinction betwe en the terms “units” and “standards” be established and kept in mind.  
 
A unit is a special quantity in terms of which other quantities are expressed.  In general, a unit is fixed by definition 
and is independent of such physical conditions as temperature.  Examples:  the meter, the liter, the gram, the yard, 
the pound, the gallon.  
 
A standard  is a physical realization or representation of a unit.  In general, it is not entirely independent of physical 
conditions, and it is a representation of the unit only under specified conditions.  For example, a meter standard has a 
length of one meter when at some definite temperature and supported in a certain manner.  If supported in a different 
manner, it might have to be at a different temperature to have a length o f one meter.  
 
2.1. Origin and Early History of Units and Standards.  
 
2.1.1.  General Survey of Early History of Measurement Systems.  – Weights and measures were 
among the earliest tools invented by man.  Primitive societies needed rudimentary measures for many tasks:  
constructing dwellings of an appropriate size and shape, fashioning clothing, or bartering food or raw 
materials.  
 
Man understandably turned first to parts of the body and the natural surroundings for measuring instruments.  
Early Babylonian and Egyptian records and the Bible indicate that length was first measured with the  Handbook 44 2015 2016  
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 forearm, hand, or finger and that time was measur ed by the periods of the sun, moon, and other heavenly 
bodies.  When it was necessary to compare the capacities of containers such as gourds or clay or metal vessels, they were filled with plant seeds which were then counted to measure the volumes.  When m eans for 
weighing were invented, seeds and stones served as standards.  For instance, the “carat,” still used as a unit 
for gems, was derived from the carob seed.  
 Our present knowledge of early weights and measures comes from many sources.  Archaeologists  have 
recovered some rather early standards and preserved them in museums.  The comparison of the dimensions of buildings with the descriptions of contemporary writers is another source of information.  An interesting 
example of this is the comparison of t he dimensions of the Greek Parthenon with the description given by 
Plutarch from which a fairly accurate idea of the size of the Attic foot is obtained.  In some cases, we have 
only plausible theories and we must sometimes select the interpretation to be g iven to the evidence.  
 
For example, does the fact that the length of the double -cubit of early Babylonia was equal (within two parts 
per thousand) to the length of the seconds pendulum at Babylon suggest a scientific knowledge of the 
pendulum at a very ear ly date, or do we merely have a curious coincidence?  By studying the evidence given 
by all available sources, and by correlating the relevant facts, we obtain some idea of the origin and 
development of the units.  We find that they have changed more or le ss gradually with the passing of time in a 
complex manner because of a great variety of modifying influences.  We find the units modified and grouped into measurement systems:  the Babylonian system, the Egyptian system, the Phileterian system of the Ptole maic age, the Olympic system of Greece, the Roman system, and the British system, to mention only a 
few. 
 
2.1.2.  Origin and Development of Some Common Customary Units.  – The origin and development of 
units of measurement has been investigated in considerab le detail and a number of books have been written 
on the subject.  It is only possible to give here, somewhat sketchily, the story about a few units.  
 
Units of length:  The cubit  was the first recorded unit used by ancient peoples to measure length.  There were 
several cubits of different magnitudes that were used.  The common cubit was the length of the forearm from the elbow to the tip of the middle finger.  It was divided into the span of the hand (one -half cubit), the palm or 
width of the hand (one sixt h), and the digit or width of a finger (one twenty- fourth).  The Royal or Sacred 
Cubit, which was 7  palms or 28 digits long, was used in constructing buildings and monuments and in 
surveying.  The inch, foot, and yard  evolved from these units through a complicated transformation not yet 
fully understood.  Some believe they evolved from cubic measures; others believe they were simple proportions or multiples of the cubit.  In any case, the Greeks and Romans inherited th e foot from the 
Egyptians.  The Roman foot was divided into both 12 unciae (inches) and 16  digits.  The Romans also 
introduced the mile of 1000 paces or double steps, the pace being equal to five Roman feet.  The Roman mile 
of 5000 feet was introduced into  England during the occupation.  Queen Elizabeth, who reigned from 1558 to 
1603, changed, by statute, the mile to 5280 feet or 8  furlongs, a furlong being 40  rods of 5½  yards each.  
 
The introduction of the yard as a unit of length came later, but its origin is not definitely known.  Some 
believe the origin was the double cubit, others believe that it originated from cubic measure.  Whatever its 
origin, the early yard was divided by the binary method into 2, 4, 8, and 16 parts called the half -yard, span, 
finger, and nail.  The association of the yard with the “gird” or circumference of a person’s waist or with the 
distance from the tip of the nose to the end of the thumb of Henry  I are probably standardizing actions, since 
several yards were in use in Great B ritain.  
 
The point , which is a unit for measuring print type, is recent.  It originated with Pierre Simon Fournier in 
1737.  It was modified and developed by the Didot brothers, Francois Ambroise and Pierre Francois, in 1755.  
The point was first used in the United States in 1878 by a Chicago type foundry (Marder, Luse, and 
Company).  Since 1886, a point has been exactly 0.351 459 8 millimeters, or about 1/72 inch.  
 
Units of mass:  The grain was the earliest unit of mass and is the smallest unit in the apot hecary, avoirdupois, 
Tower, and Troy systems.  The early unit was a grain of wheat or barleycorn used to weigh the precious 
metals silver and gold.  Larger units preserved in stone standards were developed that were used as both units 
of mass and of moneta ry currency.  The pound  was derived from the mina used by ancient civilizations.  A  Handbook 44 2015 2016  
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 smaller unit was the shekel, and a larger unit was the talent.  The magnitude of these units varied from place to place.  The Babylonians and Sumerians had a system in whic h there were 60  shekels in a mina and 
60 minas in a talent.  The Roman talent consisted of 100  libra (pound) which were smaller in magnitude than 
the mina.  The Troy pound used in England and the United States for monetary purposes, like the Roman pound, w as divided into 12 ounces, but the Roman uncia (ounce) was smaller.  The carat  is a unit for 
measuring gemstones that had its origin in the carob seed, which later was standardized at 1/444 ounce and then 
0.2 gram.  
 
Goods of commerce were originally traded by number or volume.  When weighing of goods began, units of 
mass based on a volume of grain or water were developed.  For example, the talent in some places was 
approximately equal to the mass of one cubic foot of water.  Was this a coincidence or by design?  The 
diverse magnitudes of units having the same name, which still appear today in our dry and liquid measures, 
could have arisen from the various commodities traded.  The larger avoirdupois pound  for goods of 
commerce might have been based on volume of water, which has a higher bulk density than grain.  For 
example, the Egyptian hon was a volume unit about 11 % larger than a cubic palm and corresponded to one 
mina of water.  It was almost identical in volume to the present U.S. pint.  
 
The stone , quarter , hundredweight , and ton  were larger units of mass used in Great Britain.  Today only the 
stone continues in customary use for measuring personal body weight.  The present stone is 14  pounds, but an 
earlier unit ap pears to have been 16  pounds.  The other units were multiples of 2, 8, and 160 times the stone, 
or 28, 112, and 2240  pounds, respectively.  The hundredweight was approximately equal to two talents.  In 
the United States the ton of 2240  pounds is called the  “long ton.”  The “short ton” is equal to 2000 pounds.  
 Units of time and angle:  We can trace the division of the circle into 360  degrees and the day into hours, 
minutes, and seconds to the Babylonians who had a sexagesimal system of numbers.  The 360 degrees may 
have been related to a year of 360  days.  
 
2.2. The Metric System.  
 
2.2.1.  Definition, Origin, and Development.  – Metric systems of units have evolved since the adoption 
of the first well -defined system in France in 1791.  During this evolution the  use of these systems spread 
throughout the world, first to the non -English- speaking countries, and more recently to the English- speaking 
countries.  The first metric system was based on the centimeter, gram, and second (cgs) and these units were 
particula rly convenient in science and technology.  Later metric systems were based on the meter, kilogram, 
and second (mks) to improve the value of the units for practical applications.  The present metric system is the International System of Units (SI).  It is a lso based on the meter, kilogram and second as well as 
additional base units for temperature, electric current, luminous intensity, and amount of substance.  The International System of Units is referred to as the modern metric system.  
 
The adoption of the  metric system in France was slow, but its desirability as an international system was 
recognized by geodesists and others.  On May  20, 1875, an international treaty known as the International 
Metric Convention or the Treaty of the Meter was signed by seve nteen countries including the United States.  
This treaty established the following organizations to conduct international activities relating to a uniform 
system for measurements:  
 
(1) The General Conference on Weights and Measures (French initials:  CGPM), an intergovernmental 
conference of official delegates of member nations and the supreme authority for all actions;  
 (2) The International Committee of Weights and Measures (French initials:  CIPM), consisting of 
selected scientists and metrologists,  which prepares and executes the decisions of the CGPM and is 
responsible for the supervision of the International Bureau of Weights and Measures;  
 (3) The International Bureau of Weights and Measures (French initials:  BIPM), a permanent laboratory 
and wo rld center of scientific metrology, the activities of which include the establishment of the  Handbook 44 2015 2016  
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 basic standards and scales of the principal physical quantities and maintenance of the international 
prototype standards.  
 
The National Institute of Standards and Technology provides official United States representation in these 
organizations.  The CGPM, the CIPM, and the BIPM have been major factors in the continuing refinement of 
the metric system on a scientific basis and in the evolution of the International Sy stem of Units.  
 Multiples and submultiples of metric units are related by powers of ten.  This relationship is compatible with 
the decimal system of numbers and it contributes greatly to the convenience of metric units.  
 
2.2.2.  International System of Units. – At the end of World War  II, a number of different systems of 
measurement still existed throughout the world.  Some of these systems were variations of the metric system, and others were based on the customary inch- poundU.S. customary  system of the  English -speaking countries.  
It was recognized that additional steps were needed to promote a worldwide measurement system.  As a result 
the 9th GCPM, in 1948, asked the ICPM to conduct an international study of the measurement needs of the 
scientific, te chnical, and educational communities.  Based on the findings of this study, the 10th General 
Conference in 1954 decided that an international system should be derived from six base units to provide for the measurement of temperature and optical radiation in addition to mechanical and electromagnetic quantities.  The six base units recommended were the meter, kilogram, second, ampere, Kelvin degree (later 
renamed the kelvin), and the candela.  
 
In 1960, the 11th General Conference of Weights and Measures named the system based on the six base 
quantities the International System of Units, abbreviated SI from the French name:  Le Système International d’Unités.  The SI metric system is now either obligatory or permissible throughout the world.  
 
2.2.3.  Units and Standar ds of the Metric System. –  In the early metric system there were two fundamental or base 
units, the meter and the kilogram, for length and mass.  The other units of length and mass, and all units of area, volume, and compound units such as density were der ived from these two fundamental units.  
 The meter was originally intended to be one ten- millionth part of a meridional quadrant of the earth.  The 
Meter of the Archives, the platinum length standard which was the standard for most of the 19
th century, at 
first was supposed to be exactly this fractional part of the quadrant.  More refined measurements over the 
earth’s surface showed that this supposition was not correct.  In 1889, a new international metric standard of length, the International Prototype Met er, a graduated line standard of platinum -iridium, was selected from a 
group of bars because precise measurements found it to have the same length as the Meter of the Archives.  The meter was then defined as the distance, under specified conditions, betwee n the lines on the International 
Prototype Meter without reference to any measurements of the earth or to the Meter of the Archives, which it 
superseded.  Advances in science and technology have made it possible to improve the definition of the meter 
and r educe the uncertainties associated with artifacts.  From 1960 to 1983, the meter was defined as the length 
equal to 1  650 763.73 wavelengths in a vacuum of the radiation corresponding to the transition between the 
specified energy levels of the krypton 86  atom.  Since 1983 the meter has been defined as the length of the 
path traveled by light in a vacuum during an interval of 
1/299 792 458 of a second.  
 
The kilogram, originally defined as the mass of one cubic decimeter of water at the temperature of maximum 
density, was known as the Kilogram of the Archives.  It was replaced after the International Metric 
Convention in 1875 by the International Prototype Kilogram which became the unit of mass without 
reference to the mass of a cubic decimeter of water  or to the Kilogram of the Archives.  Each country that 
subscribed to the International Metric Convention was assigned one or more copies of the international standards; these are known as National Prototype Meters and Kilograms.  
 
The liter is a unit of ca pacity or volume.  In 1964, the 12
th GCPM redefined the liter as being one cubic 
decimeter.  By its previous definition –  the volume occupied, under standard conditions, by a quantity of pure 
water having a mass of one kilogram –  the liter was larger than the cubic decimeter by 28  parts per 1  000 000.  
Except for determinations of high precision, this difference is so small as to be of no consequence.  
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 The modern metric system (SI) includes two classes of units:  
 
(a) base units for length, mass, time, temperature, electric current, luminous intensity, and amount 
of substance; and  
 
(b) derived  units for all other quantities (e.g., work, force, power) expressed in terms of the seven 
base units.  
 
For details, see NIST Special Pub lication  330 (2001 2008), The International System of Units (SI) and NIST 
Special Publication  811 (1995 2008 ), Guide for the Use of the International System of Units.  
 
2.2.4.  International Bureau of Weights and Measures. –  The International Bureau of Weights and Measures 
(BIPM) was established at Sèvres, a suburb of Paris, France, by the International Metric Convention of May 20, 1875.  The BIPM maintains the International Prototype Kilogram, many secondary standards, and 
equipment for comparing standards and making precision measurements.  The Bureau, funded by assessment of the signatory governments, is truly international.  In recent years the scope of the work at the Bureau has 
been considerably broadened.  It now carri es on researches in the fields of electricity, photometry and 
radiometry, ionizing radiations, and time and frequency besides its work in mass, length, and thermometry.  
 
2.2.5.  Status of the Metric System in the United States.  – The use of the metric system in t his country was 
legalized by Act of Congress in 1866, but was not made obligatory then or since. Following the signing of the 
Convention of the Meter in 1875, the United States acquired national prototype standards for the meter and 
the kilogram.  U.S. Pro totype Kilogram No.  20 continues to be the primary standard for mass in the United 
States.  It is recalibrated from time to time at the BIPM.  The prototype meter has been replaced by modern 
stabilized lasers following the most recent definition of the meter.  
 
From 1893 until 1959, the yard was defined as equal exactly to 
3600/3937 meter.  In 1959, a small change was 
made in the definition of the yard to resolve discrepancies both in this country and abroad.  Since 1959, we 
define the yard as equal exactly to 0.9144 meter; the new yard is shorter than the old yard by exactly two 
parts in a million.  At the same time, it was decided that any data expressed in feet derived from geodetic 
surveys within the United States would continue to bear the relationship a s defined in 1893 (one foot equals 
1200/3937 meter).  We call this foot the U.S. Survey Foot, while the foot defined in 1959 is called the 
International Foot.  Measurements expressed in U.S. statute miles, survey feet, rods, chains, links, or the squares t hereof, and acres should be converted to the corresponding metric values by using pre- 1959 
conversion factors if more than five significant figure accuracy is required.  
 Since 1970, actions have been taken to encourage the use of metric units of measuremen t in the United States.  
A brief summary of actions by Congress is provided below as reported in the Federal Register Notice dated July 28, 1998.  
 
Section  403 of Public Law  93-380, the Education Amendment of 1974, states that it is the policy of the 
United  States to encourage educational agencies and institutions to prepare students to use the metric system 
of measurement as part of the regular education program.  Under both this act and the Metric Conversion Act 
of 1975, the “metric system of measurement” is defined as the International System of Units as established in 
1960 by the General Conference on Weights and Measures and interpreted or modified for the United States 
by the Secretary of Commerce (Section  4(4)- Public  Law 94-168; Section  403(a)(3) - Public Law 93-380).  
The Secretary has delegated authority under these subsections to the Director of the National Institute of 
Standards and Technology.  
 
Section  5164 of Public Law  100-418, the Omnibus Trade and Competitiveness Act of 1988, amends Public 
Law 94-168, The Metric Conversion Act of 1975.  In particular, Section  3, The Metric Conversion Act is 
amended to read as follows:  
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 “Sec.  3.  It is therefore the declared policy of the United States – 
 (1) to designate the metric system of measurement as the p referred system of weights and measures for 
United States trade and commerce;  
 (2) to require that each federal agency, by a date certain and to the extent economically feasible by the 
end of the fiscal year 1992, use the metric system of measurement in its procurements, grants, and other business -related activities, except to the extent that such use is impractical or is likely to cause 
significant inefficiencies or loss of markets to U.S. firms, such as when foreign competitors are 
producing competing products in non- metric units;  
 
(3) to seek ways to increase understanding of the metric system of measurement through educational 
information and guidance and in government publications; and  
 
(4) to permit the continued use of traditional systems of weights  and measures in nonbusiness 
activities.”  
 The Code of Federal Regulations makes the use of metric units mandatory for agencies of the federal 
government.  (Federal Register, Vol.  56, No.  23, page  160, January  2, 1991.)  
 
2.3. British and United States Syst ems of Measurement.  – In the past, the customary system of weights and 
measures in the British Commonwealth countries and that in the United States were very similar; however, the SI 
metric system is now the official system of units in the United Kingdom, while the customary units are still 
predominantly used in the United States.  Because references to the units of the old British customary system are still found, the following discussion describes the differences between the U.S. and British customary sys tems of 
units.  
 After 1959, the U.S. and the British inches were defined identically for scientific work and were identical in commercial usage.  A similar situation existed for the U.S. and the British pounds, and many relationships, such as 
12 inches  = 1 foot, 3 feet = 1 yard, and 1760 yards  = 1 international mile, were the same in both countries; but there 
were some very important differences.  
 
In the first place, the U.S. customary bushel and the U.S. gallon, and their subdivisions differed from the 
corresponding British Imperial units.  Also the British ton is 2240  pounds, whereas the ton generally used in the 
United States is the short ton of 2000  pounds.  The American colonists adopted the English wine gallon of 231  cubic 
inches.  The English of that period used this wine gallon and they also had another gallon, the ale gallon of 
282 cubic inches.  In 1824, the British abandoned these two gallons when they adopted the British Imperial gallon, 
which they defined as the volume of 10 pounds of water, at a  temperature of 62  °F, which, by calculation, is 
equivalent to 277.42 cubic inches.  At the same time, they redefined the bushel as 8  gallons.  
 
In the customary British system, the units of dry measure are the same as those of liquid measure.  In the United 
States these two are not the same; the gallon and its subdivisions are used in the measurement of liquids and the 
bushel, with its subdivisions, is used in the measurement of certain dry commodities.  The U.S. gallon is divided into four liquid quar ts and the U.S. bushel into 32  dry quarts.  All the units of capacity or volume mentioned thus far are 
larger in the customary British system than in the U.S. system.  But the British fluid ounce is smaller than the U.S. 
fluid ounce, because the British qu art is divided into 40 fluid ounces whereas the U.S. quart is divided into 32 fluid 
ounces.  
 
From this we see that in the customary British system an avoirdupois ounce of water at 62  °F has a volume of one 
fluid ounce, because 10  pounds is equivalent to 160  avoirdupois ounces, and 1 gallon is equivalent to 4  quarts, or 
160 fluid ounces.  This convenient relation does not exist in the U.S. system because a U.S. gallon of water at 62  °F 
weighs about 8⅓  pounds, or 133⅓  avoirdupois ounces, and the U.S. gallon i s equivalent to 4  x 32, or 128 fluid 
ounces.  
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 1 U.S. fluid ounce  = 1.041 British fluid ounces  
1 British fluid ounce  = 0.961 U.S. fluid ounce  
1 U.S. gallon  = 0.833 British Imperial gallon  
1 British Imperial gallon  = 1.201 U.S. gallons  
 
Among other differences between the customary British and the United States measurement systems, we should note 
that they abolished the use of the troy pound in England January 6, 1879; they retained only the troy ounce and its 
subdivisions, whereas the tr oy pound is still legal in the United States, although it is not now greatly used.  We can 
mention again the common use, for body weight, in England of the stone of 14  pounds, this being a unit now unused 
in the United States, although its influence was sh own in the practice until World War  II of selling flour by the 
barrel of 196 pounds (14 stone).  In the apothecary system of liquid measure the British add a unit, the fluid scruple, 
equal to one third of a fluid drachm (spelled dram  in the United States) between their minim and their fluid drachm.  
In the United States, the general practice now is to sell dry commodities, such as fruits and vegetables, by their 
mass.  
 
2.4. Subdivision of Units.  – In general, units are subdivided by one of three methods:  ( a) decimal, into tenths; 
(b) duodecimal, into twelfths; or (c)  binary, into halves (twos).  Usually the subdivision is continued by using the 
same method.  Each method has its advantages for certain purposes, and it cannot properly be said that any one 
method is “best” unless the use to which the unit and its subdivisions are to be put is known.  
 For example, if we are concerned only with measurements of length to moderate precision, it is convenient to 
measure and to express these lengths in feet, inches, and binary fractions of an inch, thus 9 feet, 4
3/8 inches.  
However, if these lengths are to be subsequently used to calculate area or volume, that method of subdivision at 
once becomes extremely inconvenient.  For that reason, civil engineers, who are con cerned with areas of land, 
volumes of cuts, fills, excavations, etc., instead of dividing the foot into inches and binary subdivisions of the inch, divide it decimally; that is, into tenths, hundredths, and thousandths of a foot.  
 
The method of subdivision  of a unit is thus largely made based on convenience to the user.  The fact that units have 
commonly been subdivided into certain subunits for centuries does not preclude their also having another mode of subdivision in some frequently used cases where con venience indicates the value of such other method.  Thus, while 
we usually subdivide the gallon into quarts and pints, most gasoline -measuring pumps, of the price -computing type, 
are graduated to show tenths, hundredths, or thousandths of a gallon.  
 
Althou gh the mile has for centuries been divided into rods, yards, feet, and inches, the odometer part of an 
automobile speedometer shows tenths of a mile.  Although we divide our dollar into 100  parts, we habitually use and 
speak of halves and quarters.  An ill ustration of rather complex subdividing is found on the scales used by 
draftsmen.  These scales are of two types:  (a)  architects, which are commonly graduated with scales in which 
3/32, 
3/16, 1/8, ¼, 3/8, ½, ¾, 1, 1½, and 3  inches, respectively, represent  1 foot full scale, and also having a scale graduated in 
the usual manner to 1/16 inch; and (b)  engineers, which are commonly subdivided to 10, 20, 30, 40, 50, and 60 parts 
to the inch.  
 
The dictum of convenience applies not only to subdivisions of a unit but also to multiples of a unit.  Land elevations above sea level are given in feet although the height may be several miles; the height of aircraft above sea level as 
given by an altimeter is likewise given in feet, no matter how high it may be.  
 
On the o ther hand, machinists, toolmakers, gauge makers, scientists, and others who are engaged in precision 
measurements of relatively small distances, even though concerned with measurements of length only, find it 
convenient to use the inch, instead of the tent h of a foot, but to divide the inch decimally to tenths, hundredths, 
thousandths, etc., even down to millionths of an inch.  Verniers, micrometers, and other precision measuring instruments are usually graduated in this manner.  Machinist scales are common ly graduated decimally along one 
edge and are also graduated along another edge to binary fractions as small as 
1/64 inch.  The scales with binary 
fractions are used only for relatively rough measurements.  
 It is seldom convenient or advisable to use binar y subdivisions of the inch that are smaller than 
1/64.  In fact, 1/32-, 1/16-, 
or 1/8-inch subdivisions are usually preferable for use on a scale to be read with the unaided eye.   Handbook 44 2015 2016  
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2.5. Arithmetical Systems of Numbers.  – The subdivision of units of measurement is closely associated with 
arithmetical systems of numbers.  The systems of units used in this country for commercial and scientific work, 
having many origins as has already been shown, naturally show traces of the various number systems associated 
with their origins and developments.  Thus, (a)  the binary subdivision has come down to us from the Hindus, (b)  the 
duodecimal system of fractions from the Romans, (c)  the decimal system from the Chinese and Egyptians, s ome 
developments having been made by the Hindus, and (d)  the sexagesimal system (division by  60) now illustrated in 
the subdivision of units of angle and of time, from the ancient Babylonians.  The use of decimal numbers in measurements is becoming the standard practice.  
 
3. Standards of Length, Mass, and Capacity or Volume  
 
3.1. Standards of Length.  – The meter, which is defined in terms of the speed of light in a vacuum, is the unit on 
which all length measurements are based.  
 The yard is defined
4 as follows: 
 
1 yard = 0.914 4 meter, and  
 
1  inch = 25.4 millimeters exactly.  
 
3.1.1.  Calibration of Length Standards.  – NIST calibrates standards of length including meter bars, 
yard bars, miscellaneous precision line standards, steel tapes, invar geodetic tapes, precision gauge blocks, 
micrometers, and limit gauges.  It also measures the linear dimensions of miscellaneo us apparatus such as 
penetration needles, cement sieves, and hemacytometer chambers.  In general, NIST accepts for calibration 
only apparatus of such material, design, and construction as to ensure accuracy and permanence sufficient to justify calibration by the Institute.  NIST performs calibrations in accordance with fee schedules, copies of 
which may be obtained from NIST.  
 
NIST does not calibrate carpenters’ rules, machinist scales, draftsman scales, and the like.  Such apparatus, if 
they require calibr ation, should be submitted to state or local weights and measures officials.  
 
3.2. Standards of Mass.  – The primary standard of mass for this country is United States Prototype Kilogram  20, 
which is a platinum -iridium cylinder kept at NIST.  We know the va lue of this mass standard in terms of the 
International Prototype Kilogram, a platinum -iridium standard which is kept at the International Bureau of Weights 
and Measures.  
 
In Colonial Times the British standards were considered the primary standards of the  United States.  Later, the U.S. 
avoirdupois pound was defined in terms of the Troy Pound of the Mint, which is a brass standard kept at the United 
States Mint in Philadelphia.  In 1911, the Troy Pound of the Mint was superseded, for coinage purposes, by t he Troy 
Pound of the Institute.  
 
The avoirdupois pound is defined in terms of the kilogram by the relation:  
 
1 avoirdupois pound = 0.453 592 37 kilogram.
5 
 These changes in definition have not made any appreciable change in the value of the pound.  
 
                                                           
4 See Federal Register for July  1, 1959.  Also see next -to-last paragraph of 2.2.5.  
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 The gra in is 1/7000 of the avoirdupois pound and is identical in the avoirdupois, troy, and apothecary systems.  The 
troy ounce and the apothecary ounce differ from the avoirdupois ounce but are equal to each other, and equal to 
480 grains.  The avoirdupois ounce  is equal to 437.5 grains.  
 
3.2.1.  Mass and Weight.  – The mass of a body is a measure of its inertial property or how much matter it 
contains.  The weight of a body is a measure of the force exerted on it by gravity or the force needed to support it.  Grav ity on earth gives a body a downward acceleration of about 9.8  m/s
2.  (In common parlance, 
weight is often used as a synonym for mass in weights and measures.)  The incorrect use of weight in place of mass should be phased out, and the term mass used when mass is meant.  
 
Standards of mass are ordinarily calibrated by comparison to a reference standard of mass.  If two objects are 
compared on a balance and give the same balance indication, they have the same “mass” (excluding the effect 
of air buoyancy).  The forces of gravity on the two objects are balanced.  Even though the value of the 
acceleration of gravity,  g, is different from location to location, because the two objects of equal mass in the 
same location (where both masses are acted upon by the same g) will be affected in the same manner and by 
the same amount by any change in the value of  g, the two objects will balance each other under any value 
of g. 
 However, on a spring balance the mass of a body is not balanced against the mass of another body.  Instead, 
the gravitational force on the body is balanced by the restoring force of a spring.  Therefore, if a very 
sensitive spring balance is used, the indicated mass of the body would be found to change if the spring 
balance and the body were moved from  one locality to another locality with a different acceleration of 
gravity.  But a spring balance is usually used in one locality and is adjusted or calibrated to indicate mass at 
that locality.  
 
3.2.2.  Effect of Air Buoyancy.  – Another point that must be taken i nto account in the calibration and use of 
standards of mass is the buoyancy or lifting effect of the air.  A body immersed in any fluid is buoyed up by a force equal to the force of gravity on the displaced fluid.  Two bodies of equal mass, if placed one o n each 
pan of an equal -arm balance, will balance each other in a vacuum.  A comparison in a vacuum against a 
known mass standard gives “true mass.”  If compared in air, however, they will not balance each other unless they are of equal volume.  If of unequ al volume, the larger body will displace the greater volume of air and 
will be buoyed up by a greater force than will the smaller body, and the larger body will appear to be of less mass than the smaller body.  
 
The greater the difference in volume, and the greater the density of the air in which we make the comparison 
weighing, the greater will be the apparent difference in mass.  For that reason, in assigning a precise 
numerical value of mass to a standard, it is necessary to base this value on definite va lues for the air density 
and the density of the mass standard of reference.  
 
The apparent mass of an object is equal to the mass of just enough reference material of a specified density (at 
20 °C) that will produce a balance reading equal to that produced by the object if the measurements are done 
in air with a density of 1.2  mg/cm
3 at 20  °C.   The original basis for reporting apparent mass is apparent mass 
versus brass.  The apparent mass versus a density of 8.0  g/cm3 is the more recent definition, and is used 
extensively throughout the world.  The use of apparent mass versus 8.0  g/cm3 is encouraged over apparent 
mass versus brass.  The difference in these apparent mass systems is insignificant in most commercial 
weighing applications.  
 A full discussion of  this topic is given in NIST Monograph  133, Mass and Mass Values, by Paul  E. Pontius 
[for sale by the National Technical Information Service, 5285  Port Royal Road, Springfield,  VA  22161 
(COM  7450309)].  
 
3.2.3.  Calibrations of Standards of Mass. –  Standards of ma ss regularly used in ordinary trade should be tested by 
state or local weights and measures officials.  NIST calibrates mass standards submitted, but it does not 
manufacture or sell them.  Information regarding the mass calibration service of NIST and the regulations  Handbook 44 2015 2016  
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 governing the submission of standards of mass to NIST for calibration are contained in NIST Special 
Publication  250, Calibration and Related Measurement Services of NIST, latest edition.  
 
3.3. Standards of Capacity.  – Units of capacity or volume, be ing derived units, are in this country defined in 
terms of linear units.  Laboratory standards have been constructed and are maintained at NIST.  These have 
validity only by calibration with reference either directly or indirectly to the linear standards.  Similarly, 
NIST has made and distributed standards of capacity to the several states.  Other standards of capacity have been verified by calibration for a variety of uses in science, technology, and commerce.  
 
3.3.1.  Calibrations of Standards of Capacity.  – NIST makes calibrations on capacity or volume 
standards that are in the customary units of trade; that is, the gallon, its multiples, and submultiples, or in metric units.  Further, NIST calibrates precision -grade volumetric glassware which is normally in metric 
units.  NIST makes calibrations in accordance with fee schedules, copies of which may be obtained from 
NIST.  
 
3.4. Maintenance and Preservation of Fundamental Standard of Mass.  – It is a statutory responsibility of 
NIST to maintain and preserve t he national standard of mass at NIST and to realize all the other base units.  The 
U.S. Prototype Kilogram maintained at NIST is fully protected by an alarm system.  All measurements made with 
this standard are conducted in special air -conditioned laborato ries to which the standard is taken a sufficiently long 
time before the observations to ensure that the standard will be in a state of equilibrium under standard conditions 
when the measurements or comparisons are made.  Hence, it is not necessary to maint ain the standard at standard 
conditions, but care is taken to prevent large changes of temperature.  More important is the care to prevent any 
damage to the standard because of careless handling.  
 
4. Specialized Use of the Terms “Ton” and “Tonnage” 
 
As weighing and measuring are important factors in our everyday lives, it is quite natural that questions arise about 
the use of various units and terms and about the magnitude of quantities involved.  For example, the words “ton” 
and “tonnage” are used in wi dely different senses, and a great deal of confusion has arisen regarding the application 
of these terms.  
 The ton is used as a unit of measure in two distinct senses:  (1)  as a unit of mass, and (2)  as a unit of capacity or 
volume.  
 In the first sense, th e term has the following meanings:  
 
(a) The short , or net  ton of 2000 pounds.  
 
(b) The long, gross , or shipper’s  ton of 2240 pounds.  
 
(c) The metric  ton of 1000 kilograms, or 2204.6 pounds.  
 
In the second sense (capacity), it is usually restricted to uses relating to ships and has the following meaning:  
 
(a) The register  ton of 100 cubic feet.  
 
(b) The measurement  ton of 40 cubic feet.  
 
(c) The English water  ton of 224 British Imperial gallons.  
 
In the United States and Canada  the ton (mass) most commonly used is the short  ton.  In Great Britain, it is the long  
ton, and in countries using the metric system, it is the metric  ton.  The register  ton and the measurement  ton are 
capacity or volume units used in expressing the tonnag e of ships.  The English water  ton is used, chiefly in Great 
Britain, in statistics dealing with petroleum products.  
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 There have been many other uses of the term ton such as the timber  ton of 40  cubic feet and the wheat  ton of 
20 bushels, but their uses ha ve been local and the meanings have not been consistent from one place to another.  
Properly, the word “tonnage” is used as a noun only in respect to the capacity or volume and dimensions of ships, 
and to the amount of the ship’s cargo.  There are two disti nct kinds of tonnage; namely, vessel tonnage  and cargo 
tonnage  and each of these is used in various meanings.  The several kinds of vessel tonnage  are as follows:  
 
Gross tonnage , or gross register tonnage , is the total cubical capacity or volume of a ship expressed in register tons 
of 100 cubic feet, or 2.83  cubic meters, less such space as hatchways, bakeries, galleys, etc., as are exempted from 
measurement by different governments.  There is some lack of uniformity in the gross tonnages as given by differ ent 
nations due to lack of agreement on the spaces that are to be exempted.  Official merchant marine statistics of most 
countries are published in terms of the gross register tonnage .  Press references to ship tonnage  are usually to the 
gross tonnage . 
 
The net tonnage , or net register tonnage , is the gross tonnage  less the different spaces specified by maritime nations 
in their measurement rules and laws.  The spaces deducted are those totally unavailable for carrying cargo, such as 
the engine room, coal b unkers, crew quarters, chart and instrument room, etc.  The net tonnage  is used in computing 
how much cargo that can be loaded on a ship.  It is used as the basis for wharfage and other similar charges.  
 
The register under -deck tonnage  is the cubical capacity of a ship under her tonnage deck expressed in register tons.  
In a vessel having more than one deck, the tonnage deck is the second from the keel.  
 
There are several variations of displacement tonnage . 
 
The dead weight tonnage  is the difference between  the “loaded” and “light” displacement tonnages  of a vessel.  It is 
expressed in terms of the long ton of 2240 pounds, or the metric ton of 2204.6 pounds, and is the weight of fuel, 
passengers, and cargo that a vessel can carry when loaded to its maximum d raft. 
 
The second variety of tonnage, cargo tonnage , refers to the weight of the particular items making up the cargo.  In 
overseas traffic it is usually expressed in long tons of 2240 pounds or metric tons of 2204.6 pounds.  The short ton is 
only occasion ally used.  Therefore, the cargo tonnage  is very distinct from vessel tonnage . 
 
   
 
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 Appendix C. General Tables of Units of Measurement  
  
These tables have been prepared for the benefit of those requiring tables of units for occasional ready reference.  In Section  4 of this Appendix, the tables are carried out to a large number of decimal places and exact val ues are 
indicated by underlining.  In most of the other tables, only a limited number of decimal places are given, therefore making the tables better adapted to the average user.  
 
1. Tables of Metric Units of Measurement  
 
In the metric system of measurement, designations of multiples and subdivisions of any unit may be arrived at by combining with the name of the unit the prefixes deka,  hecto , and kilo  meaning, respectively, 10, 100, and 1000, and 
deci, centi , and milli,  meaning, respectively, one -tenth, one -hundredth, and one -thousandth.  In some of the 
following metric tables, some such multiples and subdivisions have not been included for the reason that these have little, if any currency in actual usage.  
 
In certain case s, particularly in scientific usage, it becomes convenient to provide for multiples larger than 1000 and 
for subdivisions smaller than one -thousandth.  Accordingly, the following prefixes have been introduced and these 
are now generally recognized:  
 
 yotta , (Y) meaning 1024 deci, (d), meaning 10-1 
 zetta , (Z), meaning 1021 centi , (c), meaning 10-2 
 exa, (E), meaning 1018 milli,  (m), meaning 10-3 
 peta, (P), meaning 1015 micro,  (µ), meaning 10-6 
 tera, (T), meaning 1012 nano,  (n), meaning 10-9 
 giga, (G), meaning 109 pico, (p), meaning 10-12 
 mega , (M), meaning 106 femto , (f), meaning 10-15 
 kilo, (k), meaning 103 atto, (a), meaning 10-18 
 hecto , (h), meaning 102 zepto , (z), meaning 10-21 
 deka , (da), meaning 101 yocto , (y), meaning 10-24 
 
 Thus  a kilometer is 1000  meters and a millimeter is 0.001  meter . 
 
Units of Length  
  
10 millimeters (mm)  = 1 centimeter (cm)  
10 centimeters  = 1 decimeter (dm) = 100  millimeters  
10 decimeters  = 1 meter (m) = 1000  millimeters  
10 meters  = 1 dekameter (dam)  
10 dekameters  = 1 hectometer ( hm) = 100  meters  
10 hectometers  = 1 kilometer (km) = 1000  meters  
 
Units of Area  
  
100 square millimeters (mm2) = 1 square centimeter (cm2) 
100 square centimeters  = 1 square decimeter (dm2) 
100 square decimeters  = 1 square meter (m2) 
100 square meters  = 1 square dekameter (dam2) = 1 are 
100 square dekameters  = 1 square hectometer (hm2) = 1  hectare (ha)  
100 square hectometers  = 1 square kilometer (km2) 
 
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 Units of Liquid Volume  
  
10 milliliters ( mL) = 1 centiliter ( cL) 
10 centiliters  = 1 deciliter ( dL) = 100  milliliters  
10 deciliters  = 1 liter6 = 1000 milliliters  
10 liters  = 1 dekaliter ( daL) 
10 dekaliters  = 1 hectoliter ( hL) = 100  liters  
10 hectoliters  = 1 kiloliter (kL) = 1000  liters  
 
Units of Volume  
  
1000  cubic millimeters (mm3) = 1 cubic centimeter (cm3) 
1000  cubic centimeters  = 1 cubic decimeter (dm3) 
 = 1 000 000 cubic millimeters  
1000  cubic decimeters  = 1 cubic meter (m3) 
 = 1 000 000 cubic centimeters  
 = 1 000 000 000 cubic millimeters  
 
Units of Mass  
  
10 milligrams (mg)  = 1 centigram (cg)  
10 centigrams  = 1 decigram (dg) = 100  milligrams  
10 decigrams  = 1 gram (g) = 1000  milligrams  
10 grams  = 1 dekagram (dag)  
10 dekagrams  = 1 hectogram ( hg) = 100  grams  
10 hectograms  = 1 kilogram (kg) = 1000  grams  
1000  kilograms  = 1 megagram (Mg) or 1  metric ton (t) 
 
2. Tables of U.S. Customary Units of Measurement7 
 
In these tables where  foot or mile is underlined, it is survey foot or U.S. statute mile rather than international foot or 
mile that is meant.  
 
Units of Length  
  
12 inches (in)  = 1 foot (ft)  
3 feet = 1 yard (yd)  
16½ feet = 1 rod ( rd), pole, or perch  
40 rods = 1 furlong (fur) = 660  feet 
8 furlongs  = 1 U.S. statute mile (mi) = 5280  feet 
1852  meters (m)  = 6076.115  49 feet (approximately)  
 = 1 international nautical mile  
                                                           
6 By action of the 12th General Conference on Weights and Measures (1964), the liter is a special name for the 
cubic decimeter.  
 
7 This section lists units of measurement that have traditionally been used in the United States.  In keeping with 
the Omnibus Trade and Competitiveness Act of 1988, the ultimate objective is to make the International System of 
Units the primary measurement system used in the United St ates.   Handbook 44 2015 2016  
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Agency No. 209.02  
    Handbook 44 2015 2016  
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Agency No. 209.02  
  
 Units of Area8 
  
144 square inches (in2) = 1 square foot (ft2) 
9 square feet  = 1 square yard (yd2) 
 = 1296  square inches  
272¼  square feet = 1 square rod (rd2) 
160 square rods  = 1 acre = 43  560 square feet 
640 acres  = 1 square mile (mi2) 
1 mile square  = 1 section of land  
6 miles  square  = 1 township  
 = 36 sections = 36  square miles  
 
Units of Volume3 
  
1728  cubic inches (in3) = 1 cubic foot (ft3) 
27 cubic feet  = 1 cubic yard (yd3) 
 
Gunter’s or Surveyors Chain Units of Measurement  
  
0.66 foot (ft) = 1 link ( li) 
100 links  = 1 chain (ch)  
 = 4 rods = 66  feet 
80 chains  = 1 U.S. statute mile (mi)  
 = 320 rods = 5280  feet 
 
Units of Liquid Volume9 
  
4 gills ( gi) = 1 pint ( pt) = 28.875  cubic inches (in3) 
2 pints  = 1 quart (qt) = 57.75  cubic inches  
4 quarts  = 1 gallon (gal) = 231  cubic inches  
 = 8 pints = 32  gills 
 
Apothecaries  Units of Liquid Volume  
  
60 minims  = 1 fluid dram ( fl dr or ƒ Ӡ) 
 = 0.225  6 cubic inch (in3) 
8 fluid drams  = 1 fluid ounce ( fl oz or ƒ ℥) 
 = 1.804  7 cubic inches  
16 fluid ounces  = 1 pint ( pt) 
 = 28.875  cubic inches  
 = 128  fluid drams  
2 pints  = 1 quart (qt) = 57.75  cubic inches  
                                                           
8 Squares and cubes of customary but not of metric units are sometimes expressed by the use of 
abbreviations rather than symbols.  For example, sq  ft means square foot, and cu  ft means cubic foot.  
9 When necessary to distinguish the liquid  pint or quart from the dry  pint or quart, the word “liquid” or the 
abbreviation “liq” should be used in combination with the name or abbreviation of the liquid  unit.    Handbook 44 2015 2016  
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Agency No. 209.02  
  = 32 fluid ounces = 256  fluid drams  
4 quarts  = 1 gallon (gal) = 231  cubic inches  
 = 128  fluid ounces = 1024  fluid drams  
 
Units of Dry Volume10 
  
2 pints ( pt) = 1 quart (qt) = 67.200  6 cubic inches (in3) 
8 quarts  = 1 peck  (pk) = 537.605  cubic inches  
 = 16 pints  
4 pecks  = 1 bushel (bu) = 2150.42  cubic inches  
 = 32 quarts  
 
Avoirdupois Units of Mass11 
 
[The “grain” is the same in avoirdupois, troy, and apothecaries units of mass.]  
 
 
 
 In “gross”  or “long” measure, the following values are recognized:  
 
112 pounds (lb)  = 1 gross or long hundredweight (cwt)7 
                                                           
10 When necessary to distinguish dry  pint or quart from the liquid  pint or quart, the word “dry” should be used in 
combination with the name or abbreviation of the dry unit.  
  
6 When necessary to distinguish the avoirdupois  dram from the apothecaries  dram, or to distinguish the 
avoirdupois  dram or ounce from the fluid  dram or ounce, or to distinguish the avoirdupois ounce or 
pound from the troy  or apothecaries  ounce or pound, the word “avoirdupois” or the abbreviation 
“avdp” should be used in combination with the name or abbreviation of the avoirdupois  unit.  
7 When the terms “hundredweight” and “ton” are used unmodified, they are commonly understood to 
mean the 100 -pound hundredweight and the 2000 -pound ton, respectively; these units may be 
designated “net” or “short” when necessary to distinguish them from the correspondi ng units in gross  or 
long measure.  
13 As of January 1, 2014, “tn” is the required abbreviation for “short ton.”  Devices manufactured between 
January  1, 2008, and December 31, 2013, may use an abbreviation other than “tn” to specify “short ton.”  
 1 µlb  = 0.000 001 pound  (lb) 
2711/32 grains (gr)  = 1 dram ( dr) 
16 drams  = 1 ounce ( oz) 
 = 437½  grains  
16 ounces  = 1 pound (lb)  
 = 256  drams  
 = 7000  grains  
100 pounds  = 1 hundredweight (cwt)12 
20 hundredweights  = 1 ton (tn)13 
 = 2000  pounds7  Handbook 44 2015 2016  
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Agency No. 209.02  
  
 20 gross or long hundredweights  = 1 gross or long ton  
 = 2240  pounds7 
 
Troy Units of Mass  
 
[The “grain” is the same in avoirdupois, troy, and apothecaries units of mass.]  
 
24 grains (gr)  = 1 pennyweight (dwt)  
20 pennyweights  = 1 ounce troy ( oz t) = 480  grains  
12 ounces troy  = 1 pound troy (lb  t) 
 = 240  pennyweights = 5760  grains  
Apothecaries  Units of Mass 
 
[The “grain” is the same in avoirdupois, troy, and apothecaries units of mass.]  
 
20 grains (gr)  = 1 scruple ( s ap or ℈) 
3 scruples  = 1 dram apothecaries ( dr ap or Ӡ)  
 = 60 grains  
8 drams apothecaries  = 1 ounce apothecaries ( oz ap or ℥) 
 = 24 scruples = 480 grains  
12 ounces  apothecaries  = 1 pound apothecaries  (lb ap) 
 = 96 drams apothecaries  
 = 288  scruples = 5760  grains  
 
3. Notes on British Units of Measurement  
 In Great Britain, the yard, the avoirdupois pound, the troy pound, and the apothecaries  pound are identical with the 
units of the same names used in the United States.  The tables of British linear measure, troy mass, and apothecaries  
mass are the same as the corresponding United States tables, except for the British spelling “drachm” in the table of apothecaries  mass.  The table of British avoirdupois mass is the same as the United States table up to 1  pound; above 
that point the table reads:  
 
14 pounds  = 1 stone  
2 stones  = 1 quarter = 28  pounds  
4 quarters  = 1 hundredweight = 112  pounds  
20 hundredweight  = 1 ton = 2240  pounds  
 
The present British gallon and bushel –  known as the “Imperial gallon” and “Imperial bushel” –  are, respect ively, 
about 20 % and 3  % larger than the United States gallon and bushel.  The Imperial gallon is defined as the volume of 
10 avoirdupois pounds of water under specified conditions, and the Imperial bushel is defined as 8 Imperial gallons.  
Also, the subd ivision of the Imperial gallon as presented in the table of British apothecaries fluid measure differs in 
two important respects from the corresponding United States subdivision, in that the Imperial gallon is divided into 
160 fluid ounces (whereas the Uni ted States gallon is divided into 128  fluid ounces), and a “fluid scruple” is 
included.  The full table of British measures of capacity (which are used alike for liquid and for dry commodities) is 
as follows:  
 
4 gills = 1 pint 
2 pints  = 1 quart  
4 quarts  = 1 gallon  
2 gallons  = 1 peck  
8 gallons (4 pecks)  = 1 bushel  
8 bushels  = 1 quarter   Handbook 44 2015 2016  
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Agency No. 209.02  
  
The full table of British apothecaries measure is as follows:  
 
20 minims  = 1 fluid scruple  
3 fluid scruples  = 1 fluid drachm  
 = 60 minims  
8 fluid drachms  = 1 fluid ounce  
20 fluid ounces  = 1 pint 
8 pints  = 1 gallon (160  fluid ounces)  
4. Tables of Units of Measurement  
(all underlined  figures are exact)  
 
Units of Length -  International Measure14 
 
Units  Inches  Feet Yards  Miles  Centimeters  Meters  
1 inch      = 1 0.083 333 33 0.027 777 78  0.000  015 782 83 2.54 0.025  4 
1 foot      = 12 1 0.333 333 3  0.000  189 393 9 30.48 0.304  8 
1 yard      = 36 3 1 0.000  568 181 8 91.44 0.914  4 
1 mile      = 63 360 5 280 1 760 1 160 934.4 1609.344  
1 centimeter      =    0.393 700 8  0.032 808  40 0.010 936 13  0.000  006 213 712 1 0.01 
1 meter      = 39.370 08  3.280 840  1.093 613  0.000  621 371 2 100 1 
 
Units of Length -  Survey Measure9 
 
Units  Links  Feet Rods  Chains  Miles  Meters  
1 link  = 1 0.66 0.04 0.01 0.000 125  0.201 168 4  
1 foot  = 1.515 152  1 0.060 606 06  0.015 151 52  0.000 189 393 9  0.304 800 6  
1 rod = 25 16.5 1 0.25 0.003 125  5.029 210  
1 chain  = 100 66 4 1 0.0125  20.116 84  
1 mile  = 8 000 5 280 320 80 1 1609.347  
1 meter  = 4.970 960    3.280 833  0.198 838 4  0.049 709 60  0.000 621 369 9  1 
 
                                                           
14 One inte rnational foot   = 0.999 998 survey foot (exactly)  
 One international mile   = 0.999 998 survey mile (exactly)  
  Handbook 44 2015 2016  
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Agency No. 209.02  
  
 Units of Area -  International Measure15 
(all underlined  figures are exact)  
 
Units  Square Inches  Square Feet  Square Yards  
1 square inch   = 1 0.006 944 444 0.000 771 604 9 
1 square foot   = 144 1 0.111 111 1  
1 square yard   = 1 296  9 1 
1 square mile   = 4 014 489 600 27 878 400 3 097 600  
1 square centimeter   = 0.155 000 3  0.001 076 391 0.000 119 599 0  
1 square meter   = 1550.003 10.763 91  1.195 990  
Note :  1 survey foot  = 1200/3937 meter (exactly)   
 1 international foot  = 12 x 0.0254 meter (exactly)  
 1 international foot  = 0.0254 x 39.37 survey foot (exactly  
  
Units  Square Miles  Square Centimeters  Square Meters  
1 square inch  = 0.000  000 000 249 097 7 6.451 6  0.000 645 16  
1 square foot  = 0.000  000 035 870 06 929.030 4  0.092 903 04  
1 square yard  = 0.000  000 322 830 6 8361.273 6  0.836 127 36  
1 square mile  = 1 25 899 881 103.36  2 589 988.110 336  
1 square centimeter  = 0.000  000 000 038 610 22 1 0.0001  
1 square meter  = 0.000  000 386 102 2 10 000  1 
 
Units of Area -  Survey Measure10, 16 
 
Units  Square Feet Square Rods  Square Chains  Acres  
1 square foot  = 1 0.003 673 095  0.000 229 568 4  0.000 022 956 84  
1 square rod  = 272.25  1 0.062 5  0.006 25  
1 square chain  = 4 356 16 1 0.1 
1 acre = 43 560  160 10 1 
                                                           
15 One square survey foot     = 1.000 004 square international feet  
 One square survey mile     = 1.000 004 square international miles  
10 One square survey foot     = 1.000 004 square international feet  
  One square survey mile   = 1.000 004 square international miles  
 
16 One international foot   = 0.999 998 survey foot (exactly)  
  One international mile   = 0.999 998 survey mile (exactly)   Handbook 44 2015 2016  
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Agency No. 209.02  
 1 square mile  = 27 878 400  102 400  6 400 640 
1 square meter  = 10.763 87  0.039 536 70  0.002 471 044  0.000 247 104 4  
1 hectare  =        107 638.7  395.367 0  24.710 44  2.471 044  
  
Units  Square Miles  Square Meters  Hectares  
1 square foot  = 0.000 000 035 870 06  0.092 903 41  0.000 009 290 341  
1 square rod  = 0.000 009 765 625  25.292 95  0.002 529 295  
1 square chain  = 0.000 156 25  404.687 3  0.040 468 73  
1 acre = 0.001 562 5  4 046.873  0.404 687 3  
1 square mile  = 1 2 589 998  258.999 8  
1 square meter  = 0.000 000 386 100 6  1 0.000 1  
1 hectare  = 0.003 861 006  10 000  1 
 
Units of Volume  
(all underlined  figures are exact)  
Units  Cubic Inches  Cubic Feet  Cubic Yards  
1 cubic inch  = 1 0.000 578 703 7  0.000 021 433 47  
1 cubic foot  = 1 728 1 0.037 037 04  
1 cubic yard  = 46 656  27 1 
1 cubic centimeter  = 0.061 023 74  0.000 035 314 67  0.000 001 307 951  
1 cubic decimeter  = 61.023 74  0.035 314 67  0.001 307 951  
1 cubic meter  = 61 023.74  35.314 67  1.307 951  
 
 
Units  Milliliters  
(Cubic Centimeters)  Liters  
(Cubic Decimeters)  Cubic Meters  
1 cubic inch  = 16.387 064  0.016 387  064 0.000 016 387 064  
1 cubic foot  = 28 316.846 592  28.316 846 592  0.028 316 846 592  
1 cubic yard  = 764 554.857 984  764.554 857 984  0.764 554 857 984  
1 cubic centimeter  = 1 0.001 0.000 001  
1 cubic decimeter  = 1 000 1 0.001 
1 cubic meter  = 1 000 000  1000 1 
  Handbook 44 2015 2016  
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Agency No. 209.02  
  
 Units of Capacity or Volume -  Dry Volume Measure 
 
Units  Dry Pints  Dry Quarts  Pecks  Bushels  
1 dry pint  = 1 0.5 0.062 5  0.015 625  
1 dry quart  = 2 1 0.125 0.031 25  
1 peck  = 16 8 1 0.25 
1 bushel  = 64 32 4 1 
1 cubic inch  = 0.029 761 6  0.014 880 8  0.001 860 10  0.000 465 025  
1 cubic foot  = 51.428 09  25.714 05  3.214 256  0.803 563 95  
1 liter  = 1.816 166  0.908 083 0  0.113 510 4  0.028 377 59  
1 cubic meter  =            1 816.166  908.083 0  113.510 4  28.377 59  
 
Units  Cubic Inches  Cubic Feet  Liters  Cubic Meters  
1 dry pint  = 33.600 312 5  0.019 444 63  0.550 610 5  0.000 550 610 5  
1 dry quart  = 67.200 625  0.038 889 25  1.101 221  0.001 101 221  
1 peck  = 537.605  0.311 114  8.809 768  0.008 809 768  
1 bushel  = 2 150.42  1.244 456  35.239 070 166 88  0.035 239 070 166 88  
1 cubic inch  = 1 0.000 578 703 7  0.016 387 064  0.000 016 387 064  
1 cubic foot  = 1728 1 28.316 846 592  0.028 316 846 592  
1 liter  = 61.023 74  0.035 314 67  1 0.001 
1 cubic meter  = 61 023.74  35.314 67  1000 1 
 
Units of Capacity or Volume -  Liquid Volume Measure  
(All underlined figures are exact)  
 
Units  Minims  Fluid Drams  Fluid Ounces  Gills  
1 minim  = 1 0.016 666 67  0.002 083 333  0.000 520 833 3  
1 fluid dram  = 60 1 0.125 0.031 25  
1 fluid ounce  = 480 8 1 0.25 
1 gill = 1 920 32 4 1 
1 liquid  pint = 7 680 128 16 4 
1 liquid quart  = 15 360  256 32 8 
1 gallon  = 61 440  1024 128 32 
1 cubic inch  = 265.974 0  4.432 900  0.554 112 6  0.138 528 1  
1 cubic foot  = 459 603.1  7660.052  957.506 5  239.376 6  
1 milliliter  = 16.230 73  0.270 512 2  0.033 814 02  0.008 453 506  
1 liter  = 16 230.73  270.512 2  33.814 02  8.453 506  
 
  Handbook 44 2015 2016  
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Agency No. 209.02  
 Units  Liquid Pints  Liquid Quarts  Gallons  Cubic Inches  
1 minim  = 0.000 130 208 3  0.000 065 104 17  0.000 016 276 04  0.003 759 766  
1 fluid dram  = 0.007 812 5  0.003 906 25  0.000 976 562 5  0.225 585 94  
1 fluid ounce  = 0.062 5  0.031 25  0.007 812 5  1.804 687 5  
1 gill = 0.25 0.125 0.031 25  7.218 75  
1 liquid pint = 1 0.5 0.125 28.875  
1 liquid quart  = 2 1 0.25 57.75 
1 gallon  = 8 4 1 231 
1 cubic inch  = 0.034 632 03  0.017 316 02  0.004 329 004  1 
1 cubic foot  = 59.844 16  29.922 08  7.480 519  1 728 
1 milliliter  = 0.002 113 376  0.001 056 688  0.000 264 172 1  0.061 023 74  
1 liter  = 2.113 376  1.056 688  0.264 172 1  61.023 74  
 
Units  Cubic Feet  Milliliters  Liters  
1 minim  = 0.000 002 175 790  0.061 611 52  0.000 061 611 52  
1 fluid dram  = 0.000 130 547 4  3.696 691  0.003 696 691  
1 fluid ounce  = 0.001 044 379  29.573 53  0.029 573 53  
1 gill = 0.004 177 517  118.294 1  0.118 294 1  
1 liquid pint = 0.016 710 07  473.176 5  0.473 176 5  
1 liquid quart  = 0.033 420 14  946.352 9  0.946 352 9  
1 gallon  = 0.133 680 6  3785.411 784  3.785 411 784  
1 cubic inch  = 0.000 578 703 7  16.387 06  0.016 387 06  
1 cubic foot  = 1 28 316.85  28.316 85  
1 milliliter  = 0.000 035 314 67  1 0.001  
1 liter  = 0.035 314 67  1 000 1 
 
Units of  Mass Not Less Than Avoirdupois Ounces  
(all underlined figures are exact)  
 
Units  Avoirdupois  
Ounces  Avoirdupois  
Pounds  Short Hundred-
weights  Short Tons  
1 avoirdupois ounce  = 1 0.0625  0.000 625  0.000 031 25  
1 avoirdupois pound = 16 1 0.01 0.000 5  
1 short  
hundredweight  = 1 600 100 1 0.05 
1 short ton  = 32 000  2 000 20 1 
1 long ton = 35 840  2 240 22.4 1.12 
1 kilogram  = 35.273 96  2.204 623  0.022 046 23  0.001 102 311  
1 metric ton  = 35 273.96  2204.623  22.046 23  1.102 311   Handbook 44 2015 2016  
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Agency No. 209.02  
  
  
Units  Long Tons  Kilograms  Metric Tons  
1 avoirdupois ounce  = 0.000 027 901 79  0.028 349 523 125  0.000 028 349 523 125  
1 avoirdupois pound = 0.000 446 428 6  0.453 592 37  0.000 453 592 37  
1 short hundredweight  = 0.044 642 86  45.359 237  0.045 359 237  
1 short ton  = 0.892 857 1  907.184 74  0.907 184 74  
1 long ton = 1 1016.046 908 8  1.016 046 908 8  
1 kilogram  = 0.000 984 206 5  1 0.001 
1 metric ton  = 0.984 206 5  1 000 1 
Units of Mass Not Greater Than Pounds and Kilograms  
(all underlined figures are exact)  
Units  Grains  Apothecaries 
Scruples  Pennyweights  Avoirdupois 
Drams  
1 grain  = 1 0.05 0.041 666 67  0.036 571 43  
1 apoth. scruple  = 20 1 0.833 333 3  0.731 428 6  
1 pennyweight  = 24 1.2 1 0.877 714 3  
1 avdp. dram  = 27.343 75  1.367 187 5  1.139 323  1 
1 apoth. dram  = 60 3 2.5 2.194 286  
1 avdp. ounce  = 437.5 21.875  18.229 17  16 
1 apoth. or troy oz.  = 480 24 20 17.554 29  
1 apoth. or troy pound = 5 760 288 240 210.651 4  
1 avdp. pound  = 7 000 350 291.666 7  256 
1 milligram  = 0.015 432 36  0.000 771 617 9  0.000 643 014 9  0.000 564 383 4  
1 gram  = 15.432 36  0.771 617 9  0.643 014 9  0.564 383 4  
1 kilogram  = 15432.36  771.617 9   643.014 9  564.383 4  
  Handbook 44 2015 2016  
Markup Copy 
Agency No. 209.02  
 Units  Apothecaries 
Drams  Avoirdupois 
Ounces  Apothecaries or 
Troy Ounces  Apothecaries or 
Troy Pounds  
1 grain  = 0.016 666 67  0.002 285 714  0.002 083 333  0.000 173 611 1  
1 apoth. scruple  = 0.333 333 3  0.045 714 29  0.041 666 67  0.003 472 222  
1 pennyweight  = 0.4 0.054 857 14  0.05 0.004 166 667  
1 avdp. dram  = 0.455 729 2  0.062 5  0.56 966 15  0.004 747 179  
1 apoth. dram  = 1 0.137 142 9 0.125 0.010 416 67  
1 avdp. ounce  = 7.291 667  1 0.911 458 3  0.075 954 86  
1 apoth. or troy ounce  = 8 1.097 143  1 0.083 333 333  
1 apoth. or troy pound = 96 13.165 71  12 1 
1 avdp. pound  = 116.666 7  16 14.583 33  1.215 278  
1 milligram  = 0.000 257 206 0  0.000 035 273 96  0.000 032 150 75  0.000 002 679 229  
1 gram  = 0.257 206 0  0.035 273 96  0.032 150 75  0.002 679 229  
1 kilogram  = 257.206 0  35.273 96  32.150 75  2.679 229  
 
Units  Avoirdupois 
Pounds  Milligrams  Grams  Kilograms  
1 grain  = 0.000 142 857 1  64.798 91  0.064 798 91  0.000 064 798 91  
1 apoth. scruple  = 0.002 857 143  1 295.978 2  1.295 978 2  0.001 295 978 2  
1 pennyweight  = 0.003 428 571  1 555.173 84  1.555 173 84  0.001 555 173 84  
1 avdp. dram  = 0.003 906 25  1 771.845 195 312 5  1.771 845 195 312 5  0.001 771 845 195 312 5  
1 apoth. dram  = 0.008 571 429  3 887.934 6  3.887 934 6  0.003 887 934 6  
1 avdp. ounce  = 0.062 5  28 349.523 125  28.349 523 125  0.028 349 523 125  
1 apoth. or troy  
ounce  = 0.068 571 43  31 103.476 8  31.103 476 8  0.031 103 476 8  
1 apoth. or troy  
pound = 0.822 857 1  373 241.721 6  373.241 721 6  0.373 241 721 6  
1 avdp. pound  = 1 453 592.37  453.592 37  0.453 592 37  
1 milligram  = 0.000 002 204 623  1 0.001 0.000 001  
1 gram  = 0.002 204 623  1 000 1 0.001 
1 kilogram  = 2.204 623  1 000 000  1 000 1 
  Handbook 44 2015 2016  
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Agency No. 209.02  
  
 5. Tables of Equivalents  
 
In these tables it is necessary to differentiate between the “international foot” and the “survey foot.”  Therefore, the 
survey foot is underlined.  
 When the name of a unit is enclosed in brackets (thus, [1  hand] . . . ), this indicates (1)  that the unit is not in general 
current use in the United States, or (2)  that the unit is believed to be based on “custom and usage” rather than on 
formal authoritative definition.  
 
Equivalents involving decimals are, in most instance s, rounded off to the third decimal place except where they are 
exact, in which cases these exact equivalents are so designated.  The equivalents of the imprecise units “tablespoon” and “teaspoon” are rounded to the nearest milliliter.  
 
Units of Length  
angstrom ( )17 0.1 nanometer (exactly)  
0.000  1 micrometer (exactly)  
0.000  000 1 millimeter (exactly)  
0.000  000 004 inch  
1 cable’s length  120 fathoms (exactly)  
720 feet (exactly)  
219 meters  
1 centimeter (cm)  0.393  7 inch 
1 chain (ch)  
 (Gunter’s or surveyors)  66 feet (exactly)  
20.116 8 meters  
1 decimeter (dm)  3.937 inches  
1 dekameter (dam)  32.808 feet  
1 fathom  6 feet (exactly)  
1.828  8 meters  
1 foot (ft)  0.304  8 meter (exactly)  
1 furlong (fur) 10 chains (surveyors) (exactly)  
660 feet (exactly)  
1/8 U.S. statute mile (exactly)  
201.168 meters  
[1 hand]  4 inches  
1 inch (in)  2.54 centimeters (exactly)  
1 kilometer (km)  0.621 mile  
1 league (land)  3 U.S. statute miles (exactly)  
4.828 kilometers  
1 link (li) (Gunter’s or surveyors)  0.66 foot (exactly)  
0.201 168 meter  
                                                           
17 The angstrom is basically defined as 10−10 meter.   Handbook 44 2015 2016  
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Agency No. 209.02  
 Units of Length  
1 meter (m)  39.37 inches  
1.094 yards  
1 micrometer  0.001 millimeter (exactly)  
0.000 039 37 inch  
1 mil  0.001 inch (exactly)  
0.025 4 millimeter (exactly)  
1 mile (mi) (U.S. statute)18 5280 feet survey (exactly)  
1.609 kilometers  
1 mile (mi) (international)  5280 feet international (exactly)  
1 mile (mi) (international nautical)19 1.852 kilometers (exactly)  
1.151 survey miles  
1 millimeter (mm)  0.039 37 inch  
0.001 meter (exactly)  
1 nanometer (nm)  0.000 000 039 37 inch  
1 Point (typography)  0.013 837 inch (exactly)  
1/72 inch (approximately)  
0.351 millimeter  
1 rod (rd), pole, or perch  16½ feet (exactly)  
5.029 2 meters  
1 yard (yd)  0.914 4 meter (exactly)  
 
                                                           
18 The term “statute mile” originated with Queen Elizabeth  I who changed the definition of the mile from 
the Roman mile of 5000  feet to the statute mile of 5280  feet.  The international mile and the U.S. 
statute mile differ by about 3  millimeters although both are defined as being equal to 5280  feet.  The 
international mile is based on the international foot (0.3048  meter) whereas the U.S. statute mile is 
based on the survey foot (1200/3937  meter).  
19 The in ternational nautical mile of 1852  meters (6076.115  49 feet) was adopted effective July  1, 1954, 
for use in the United States.  The value formerly used in the United States was 6080.20  feet = 1  nautical 
(geographical or sea) mile.   Handbook 44 2015 2016  
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Agency No. 209.02  
  
 Units of Area  
1 acre20 43 560 square feet (exactly)  
0.405 hectare  
1 are  119.599 square yards  
0.025 acre  
1 hectare  2.471 acres  
[1 square (building)]  100 square feet  
1 square centimeter (cm2) 0.155 square inch  
1 square decimeter (dm2) 15.500 square inches  
1 square foot (ft2) 929.030 square centimeters  
1 square inch (in2) 6.451 6 square centimeters (exactly)  
1 square kilometer (km2) 247.104 acres  
0.386 square mile  
1 square meter (m2) 1.196 square yards  
10.764 square feet  
1 square mile (mi2) 258.999 hectares  
1 square millimeter (mm2) 0.002 square inch  
1 square rod  (rd2), sq pole, or sq perch  25.293 square meters  
1 square yard (yd2) 0.836 square meter  
 
Units of Capacity or Volume  
1 barrel (bbl), liquid  31 to 42 gallons21 
1 barrel (bbl), standard for fruits,  
    vegetables, and other dry  
    commodities, except cranberries  7056 cubic inches  
105 dry quarts  
3.281 bushels, struck measure  
1 barrel (bbl), standard, cranberry  5826 cubic inches  
8645/64 dry quarts  
                                                           
20 The question is often as ked as to the length of a side of an acre of ground.  An acre is a unit of area 
containing 43  560 square feet.  It is not necessarily square, or even rectangular.  But, if it is square, then 
the length of a side is equal to  (not exact).  
 
21 There are a variety of “barrels” established by law or usage.  For example, federal taxes on fermented 
liquors are based on a barrel of 31  gallons; many state laws fix the “barrel for liquids” as 31½  gallons; 
one state fixes a 36 -gallon barrel for cistern measurement; fe deral law recognizes a 40 -gallon barrel for 
“proof spirits;” by custom, 42  gallons comprise a barrel of crude oil or petroleum products for statistical 
purposes, and this equivalent is recognized “for liquids” by four states.  ft 710.208 ft 435602= Handbook 44 2015 2016  
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 Units of Capacity or Volume  
2.709 bushels, struck measure  
 
1 bushel (bu) (U.S.) struck measure   
2150.42 cubic inches (exactly)  
35.238 liters  
[1 bushel, heaped (U.S.)]  2747.715 cubic inches  
1.278 bushels, struck measure22 
[1 bushel (bu) (British Imperial)  
(struck measure)]  1.032 U.S. bushels, struck measure  
2219.36 cubic inches  
1 cord (cd) (firewood)  128 cubic feet (exactly)  
1 cubic centimeter (cm3) 0.061 cubic inch  
1 cubic decimeter (dm3) 61.024 cubic inches  
1 cubic foot (ft3) 7.481 gallons  
28.316 cubic decimeters  
1 cubic inch (in3) 0.554 fluid ounce  
4.433 fluid drams  
16.387 cubic centimeters  
1 cubic meter  (m3) 1.308 cubic yards  
1 cubic yard (yd3) 0.765 cubic meter  
1 cup, measuring 8 fluid ounces (exactly)  
237 milliliters  
½ liquid pint (exactly)  
1 dekaliter (daL)  2.642 gallons  
1.135 pecks  
1 dram, fluid (or liquid) (fl dr)  
   or ƒ Ӡ) (U.S.)  1/8 fluid ounce (exactly)  
0.226 cubic inch 3.697 milliliters  
1.041 British fluid drachms  
[1 drachm, fluid (fl dr) (British)] 0.961 U.S. fluid dram  
0.217 cubic inch 
3.552 milliliters  
1 gallon (gal) (U.S.)  231 cubic inches (exactly)  
3.785 liters  
0.833 British  gallon  
128 U.S. fluid ounces (exactly)  
[1 gallon (gal) (British Imperial)]  277.42 cubic inches  
1.201 U.S. gallons  
4.546 liters  
160 British fluid ounces (exactly)  
1 gill (gi)  7.219 cubic inches  
4 fluid ounces (exactly)  
0.118 liter  
                                                           
22 Frequently recognized as 1¼ bushels, struck measure.   Handbook 44 2015 2016  
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Agency No. 209.02  
  
 Units of Capacity or Volume  
1 hectoliter (hL)  26.418 gallons  
2.838 bushels  
1 liter (1 cubic decimeter exactly)  1.057 liquid quarts  
0.908 dry quart  
61.025 cubic inches  
1 milliliter (mL)  0.271 fluid dram  
16.231 minims  
0.061 cubic inch  
1 ounce, fluid (or liquid) (fl oz)  
   or ƒ 
 ) (U.S.)  1.805 cubic inches  
29.573 milliliters  
1.041 British fluid ounces  
[1 ounce, fluid (fl oz) (British)]  0.961 U.S. fluid ounce  
1.734 cubic inches  
28.412 milliliters  
1 peck (pk)  8.810 liters  
1 pint (pt), dry  33.600 cubic inches  
0.551 liter  
1 pint (pt), liquid  28.875 cubic inches exactly  
0.473 liter  
1 quart (qt), dry (U.S.) 67.201 cubic inches  
1.101 liters  
0.969 British quart  
1 quart (qt), liquid (U.S.)  57.75 cubic inches (exactly)  
0.946 liter  
0.833 British quart  
[1 quart (qt) (British)] 69.354 cubic inches  
1.032 U.S. dry quarts  
1.201 U.S. liquid quarts  
1 tablespoon, measuring 3 teaspoons (exactly)  
15 milliliters  
4 fluid drams  
½ fluid ounce (exactly)  
1 teaspoon, measuring ⅓ tablespoon (exactly)  
5 milliliters  
1⅓ fluid drams23 
1 water ton (English)  270.91 U.S. gallons  
224 British Imperial gallons (exactly)  
 
                                                           
23 The equivalent “1  teaspoon = 1 ⅓ fluid drams” has been found by the Bureau to correspond more closely with 
the actual capacities of “measuring” and silver teaspoons than the equivalent “1  teaspoon = 1  fluid dram,” which is 
given by a number of dictionaries.  
  Handbook 44 2015 2016  
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 Units of Mass  
1 assay ton (AT)24 29.167 grams  
1 carat (c)  200 milligrams (exactly)  
3.086 grains  
1 dram apothecaries (dr ap or 3) 60 grains (exactly)  
3.888 grams  
1 dram avoirdupois (dr avdp)  2711/32 (= 27.344) grains  
1.772 grams  
1 gamma ( γ) 1 microgram (exactly)  
1 grain  64.798 91 milligrams (exactly)  
1 gram (g)  15.432 grains  
0.035 ounce, avoirdupois  
1 hundredweight, gross or long25 
   (gross cwt)  112 pounds (exactly)  
50.802 kilograms  
1 hundredweight, gross or short  
   (cwt or net cwt)  100 pounds (exactly)  
45.359 kilograms  
1 kilogram (kg)  2.205 pounds  
1 milligram (mg)  0.015 grain  
1 ounce, avoirdupois (oz avdp)  437.5 grains (exactly)  
0.911 troy or apothecaries ounce 
28.350 grams  
1 ounce, troy or apothecaries  
   (oz t or oz ap or ℥ ) 480 grains (exactly)  
1.097 avoirdupois ounces  
31.103 grams  
1 pennyweight (dwt)  1.555 grams  
1 point  0.01 carat  
2 milligrams  
1 pound, avoirdupois (lb avdp)  7000 grains (exactly)  
1.215 troy or apothecaries pounds  
453.592 37 grams (exactly)  
1 micropound (µlb) [the Greek letter mu  
   in combination with the letters lb]  0.000 001 pound (exactly)  
1 pound, troy or apothecaries  
   (lb t or lb ap)  5760 grains (exactly)  
0.823 avoirdupois pound 
373.242 grams  
                                                           
24 Used in assaying.  The assay ton bears the same relation to the milligram that a ton of 2000 pounds avoirdupois 
bears to the ounce troy; hence the mass in milligrams of precious metal obtained fro m one assay ton of ore gives 
directly the number of troy ounces to the net ton.  
 
25 The gross or long ton and hundredweight are used commercially in the Untied States to only a very limitied 
extent, usually in restricted industrial fields.  The units are the same as the British “ton” and the “hundredweights.”   Handbook 44 2015 2016  
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 Units of Mass  
1 scruple (s ap or ℈) 20 grains (exactly)  
1.296 grams  
1 ton, gross or long26 2240 pounds (exactly)  
1.12 net tons (exactly)  
1.016 metric tons  
1 ton, metric (t)  2204.623 pounds  
0.984 gross ton 
1.102 net tons  
1 ton, net or short (tn)21 2000 pounds (exactly)  
0.893 gross ton 0.907 metric ton  
 
                                                           
 
21 As of January 1, 2014, “tn” is the required abbreviation for “ short ton. ”  Devices manufactured between 
January  1, 2008, and December 31, 2013, may use an abbreviation  other than “tn” to specify “sh ort ton.”    Handbook 44 – 2015 2016  
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Agency No. 209.02 
 Appendix D.     Definitions 
 
The specific code to which the definition applies is shown in [brackets] at the end of the definition.  Definitions for 
the General Code [1.10] apply to all codes in Handbook  44. 
 
A 
absolute value.  – The absolute value of a number is the magnitude of that number without considering the positive 
or negative sign. [2.20]  
 
acceptance test.  – The first official test of a farm milk tank, at a particular location, in which the tank is accepted as 
correct.  This test applies to newly constructed tanks, relocated used tanks, and recalibrated tanks. [4.42]  
 
accurate.  – A piece of equipment is “accurate” when its performance or value –  that is, its indications, its deliveries, 
its recorded representations, or its capacity or actual value, etc., as determined by tests made with suitable 
standards  - conforms to the standard within the applicable tole rances and other performance requirements.  
Equipment that fails so to conform is “inaccurate.”  (Also see “correct.”) [Appendix A]  
 
all-class.  – A description of a multi -class calibration that includes all the classes of a grain type. [5.56(a), 5.57]  
(Add ed 2007)  
 analog or digital recorder. – An element used with a belt -conveyor scale that continuously records the rate -of-flow 
of bulk material over the scale (formerly referred to as a chart recorder). [2.21]  
(Amended 1989)  
 
analog type.  – A system of indication or recording in which values are presented as a series of graduations in 
combination with an indicator, or in which the most sensitive element of an indicating system moves continuously 
during the operation of the device. [1.10]  
 
animal scale.  – A scale designed for weighing single heads of livestock. [2.20]  
(Amended 1987)  
 
apparent mass versus 8.0 g/cm
3. – The apparent mass of an object versus 8.0  g/cm3 is the mass of material of 
density 8.0 g/cm3 that produces exactly the same balance reading as the object when the comparison is made in air 
with a density of 1.2 mg/cm3 at 20  °C. [3.37]  
 approval seal.  – A label, tag, stamped or etched impression, or the like, indicating official approval of a device.  
(Also see “security seal.”) [1.10]  
 assumed atmospheric pressure.  – The average atmospheric pressure agreed to exist at the meter at various ranges 
of elevation, irrespective of variations in atmospheric pressure from time to time. [3.33]  
 
audit trail.  – An electronic count and/or information record of the changes to the values of the calibration or 
configuration parameters of a device. [1.10, 2.20, 2.21, 2.24, 3.30, 3.37, 5.56(a)]  
(Added 1993)  
 
automatic bulk weighing system.  – A weighing system adapted to the automatic weighing of bulk commodities in 
successive drafts of predetermined amounts, automatically recording the no -load and loaded weight values and 
accumulating the net weight of each draft. [2.22]  
 
automatic checkweigher. – An automatic weighing  system that does not require the intervention of an operator 
during the weighing process and used to subdivide items of different weights into one or more subgroups, such as Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 identifying packages that have acceptable or unacceptable fill levels according t o the value of the difference between 
their weight and a pre -determined set point.  These systems may be used to fill standard packages for compliance 
with net weight requirements. [2.24]  
(Amended 2004)  
 
automatic gravimetric filling machine (instrument).  – A filling machine or instrument that fills containers or 
packages with predetermined and virtually constant mass of product from bulk by automatic weighing, and which comprises essentially an automatic feeding device or devices associated with one or mor e weighing unit and the 
appropriate discharge devices. [2.24]  
(Added 2004)  
 
automatic hopper scale.  – One adapted to the automatic weighing of bulk commodity in successive drafts of 
predetermined amounts.  (This is not an “automatic -indicating scale” defined below.)[2.20]  
 
automatic temperature or density compen sation.  – The use of integrated or ancillar y equipment to obtain from 
the output of a volumetric meter an equivalent mass, or an equivalent liquid volume at the assigned reference 
temperature below and a pressure of 14.696 lb/in2 absolute.  
 
Cryogenic liquids:  21  °C (70  °F) [3.34]  
Hydrocarbon gas v apor:   15 °C (60  °F) [3.33]  
Liquid carbon dioxide:   21  °C (70  °F) [3.38]  
Liquefied petroleum gas (LPG) and Anhydrous ammonia:  15 °C (60  °F) [3.32]  
Petroleum liquid fuels and lubricants:  15  °C (60  °F) [3.30]  
 
automatic weighing system (AWS).  – An automatic weighing system is a weighing device that, in combination 
with other hardware and/or software components, automatically weighs discrete items and that does not require the 
intervention of an operator during the weighing process.  Examples inc lude, but are not limited to, weigh- labelers 
and checkweighers. [2.24]  
(Amended 2004)  
 
automatic zero -setting mechanism (AZSM).  – See “automatic zero -setting mechanism” under “zero -setting 
mechanism.” [2.22]  
(Amended 2010)  
 automatic zero -setting mechanism  (belt -conveyor scale).  – A zero setting device that operates automatically 
without intervention of the operator after the belt has been running empty. [2.21]  
(Added 2002)  
 automatic zero -tracking (AZT) mechanism . – Automatic means provided to maintain the zero balance indication, 
within specified limits, without the intervention of an operator. [2.20, 2.22, 2.24]  
(Amended 2010)  
 automatic -indicating scale.  – One on which the weights of applied loads of various magnitudes are automatically 
indicated through out all or a portion of the weighing range of the scale.  (A scale that automatically weighs out 
commodity in predetermined drafts, such as an automatic hopper scale, a packaging scale, and the like, is not an 
“automatic -indicating” scale.) [2.20. 2.22]  
 auxiliary indicator.  – Any indicator other than the master weight totalizer that indicates the weight of material 
determined by the scale. [2.21]  
 
axle-load scale.  – A scale permanently installed in a fixed location, having a load -receiving element specially 
adapted to determine the combined load of all wheels (1)  on a single axle or (2)  on a tandem axle of a highway 
vehicle. [2.20]    Handbook 44 – 2015 2016  
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Agency No. 209.02 
  
B 
badge.  – A metal plate affixed to the meter by the manufacturer showing the manufacturer’s name, serial number 
and model number of the meter, and its rated capacity. [3.33]  
 
balance, zero -load. – See “zero -load balance.” [2.20]  
 
balance indicator.  – A combination of elements, one or both of which will oscillate with respect to the other, for 
indicating the balance condition of a nonautomatic indicating scale.  The combination may consist of two indicating edges, lines, or points, or a single edge, line, or point an d a graduated scale. [2.20]  
 
balancing mechanism.  – A mechanism (including a balance ball) that is designed for adjusting a scale to an 
accurate zero -load balance condition. [2.20]  
 
base pressure.  – The absolute pressure used in defining the gas measuremen t unit to be used, and is the gauge 
pressure at the meter plus an agreed atmospheric pressure. [3.33]  
 
basic distance rate.  – The charge for distance for all intervals except the initial interval. [5.54]  
 
basic time rate.  – The charge for time for all intervals except the initial interval. [5.54]  
 basic tolerances.  – Basic tolerances are those tolerances on under registration and on over registration, or in excess 
and in deficiency, that are established by a particular code for a particular device under all  normal tests, whether 
maintenance or acceptance.  Basic tolerances include minimum tolerance values when these are specified.  Special tolerances, identified as such and pertaining to special tests, are not basic tolerances. [1.10]  
 batching meter . – A de vice used for the purpose of measuring quantities of water to be used in a batching 
operation. [3.36]  
 beam.  – See “weighbeam.” [2.20]  
 beam scale.  – One on which the weights of loads of various magnitudes are indicated solely by means of one or 
more weighbeam bars either alone or in combination with counterpoise weights. [2.20]  
 bell prover.  – A calibrated cylindrical metal tank of the annular type with a scale thereon that, in the downward 
travel in a surrounding tank containing a sealing medium, dis places air through the meter being proved or calibrated. 
[3.33]  
 
belt-conveyor.  – An endless moving belt for transporting material from place to place. [2.21]  
 
belt-conveyor scale . – A device that employs a weighing element in contact with a belt to sense the weight of the 
material being conveyed and the speed (travel) of the material, and integrates these values to produce total delivered 
weight. [2.21]  
 belt-conveyor scale systems area.  – The scale system area refers to the scale suspension, weigh idlers attached to 
the scale suspension, 5  approach (−) idlers, and 5  retreat (+) idlers. [2.21]  
(Added 2001)  
 
belt load . – The weight of the material carried by the conveyor belt, expressed in terms of weight units per unit of 
length (e.g., pounds per foot, kilograms per meter).  Also called “belt loading.” [2.21]  
(Added 2013)  
 Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 belt revolution.  – The amount of conveyor belt movement or travel that is equivalent to the total length of the 
conveyor belt.  Also referred to as "belt circuit." [2.21]  
(Added 2013)  
 
billed weight.  – The weight used in the computation of the freight, postal, or storage charge, whether actual weight 
or dimensional weight. [5.58]  
 
binary submultiples.  – Fractional par ts obtained by successively dividing by the number  two.  Thus, one -half, 
one-fourth, one -eighth, one -sixteenth, and so on, are binary submultiples. [1.10]  
 built -for-purpose device . – Any main device or element which was manufactured with the intent that i t be used as, 
or part of, a weighing or measuring device or system. [1.10]  
(Added 2003)  
C 
calibration parameter.  – Any adjustable parameter that can affect measurement or performance accuracy and, due 
to its nature, needs to be updated on an ongoing basis to maintain device accuracy, e.g., span adjustments, 
linearization factors, and coarse zero adjustments. [2.20, 2.21, 2.24, 3.30, 3.37, 5.56(a)]  
(Added 1993)  
 
carbon dioxide liquid- measuring device.  – A system including a mechanism or machine of (a)  the meter or (b)  a 
weighing type of device mounted on a vehicle designed to measure and deliver liquid carbon dioxide.   Means may 
be provided to indicate automatically, for one of a series of unit prices, the total money value of the quantity measured . [3.38]  
 
car-wash timer.  – A timer used in conjunction with a coin -operated device to measure the time during which 
car-wash water, cleaning solutions, or waxing solutions are dispensed. [5.55]  
 
center- reading tank.  – One so designed that the gauge rod or surface gauge, when properly positioned for use, will 
be approximately in the vertical axis of the tank, centrally positio ned with respect to the tank walls. [4.43]  
 
cereal grain and oil seeds . – Agricultural commodities including, but not limited to, corn, wheat, oats, barley, flax, 
rice, sorghum, soybeans, peanuts, dry beans, safflower, sunflower, fescue seed, etc. [5.56(a) , 5.56(b)]  
 
chart recorder.  – See analog or digital recorder.  
(Amended 1989)  
 
check rate.  – A rate of flow usually 20  % of the capacity rate. [3.33]  
 
checkweighing scale.  – One used to verify predetermined weight within prescribed limits. [2.24]  
 
class of grain.  – Hard Red Winter Wheat as distinguished from Hard Red Spring Wheat as distinguished from Soft 
Red Winter Wheat, etc. [5.56(a), 5.56(b), 5.57]  
 clear interval between graduations. –  The distance between adjacent edges of successive graduations in a series of 
graduations. If the graduations are “staggered,” the interval shall be measured, if necessary, between a graduation and an extension of the adjacent graduation.  (Also see “minimum clear interval.”) [1.10]  
 
cleared.  – A taximeter is “cleared” whe n it is inoperative with respect to all fare indication, when no indication of 
fare or extras is shown and when all parts are in those positions in which they are designed to be when the vehicle on 
which the taximeter is installed is not engaged by a passe nger. [5.54]  
   Handbook 44 – 2015 2016  
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 cold-tire pressure.  – The pressure in a tire at ambient temperature. [5.53, 5.54]  
 
commercial equipment.  – See “equipment.” 
(Added 2008)  
 
computing scale.  – One that indicates the money values of amounts of commodity weighed, at predetermined  unit 
prices, throughout all or part of the weighing range of the scale. [2.20]  
 
computing type or computing type device.  – A device designed to indicate, in addition to weight or measure, the 
total money value of product weighed or measured, for one of a series of unit prices. [1.10]  
 
concave curve.  – A change in the angle of inclination of a belt conveyor where the center of the curve is above the 
conveyor. [2.21]  
 
concentrated load capacity (CLC) (also referred to as Dual Tandem Axle Capacity[DTAC]).  – A capacity rating 
of a vehicle or axle -load scale, specified by the manufacturer, defining the maximum load applied by a group of two 
axles with a centerline spaced four  feet apart and an axle width of eight  feet for which the weighbridge is designed.  
The concentrated load capacity rating is for both test and use. [2.20]  
(Added 1988) (Amended 1991, 1994, and 2003)  
 configuration parameter.  – Any adjustable or selectable parameter for a device feature that can affect the accuracy 
of a transaction or can significantly increase the potential for fraudulent use of the device and, due to its nature, 
needs to be updated only during device installation or upon replacement of a component, e.g., division value 
(increment), sensor range, and units of measurement. [2.20, 2.21, 2.24, 3.30, 3.37, 5.56(a)]  
(Added 1993)  
 
consecutive- car test train.  – A train consisting of cars weighed on a reference scale, then coupled consecutively 
and run over the coupled -in-motion railway track scale under test. [2.20]  
(Added 1990)  
 
construction materials hopper scale.  – A scale adapted to weighing construction materials such as sand, gravel, 
cement, and hot oil. [2.20]  
 
contract sale.  – A sale where a written agreement exists, prior to the point of sale, in which both buyer and selle r 
have accepted pricing conditions of the sale.  Examples include, but are not limited to:  e -commerce, club sales, or 
pre-purchase agreements.  Any devices used in the determination of quantity must comply with NIST Handbook  44. 
[3.30, 3.32, 3.37]  
(Added 1993) (Amended 2002)  
 conventional scale.  – If the use of conversion tables is necessary to obtain a moisture content value, the moisture 
meter indicating scale is called “conventional scale.”  The values indicated by the scale are dimensionless. [5.56(b)]  
 conversion table.  – Any table, graph, slide rule, or other external device used to determine the moisture content 
from the value indicated by the moisture meter. [5.56(b)]  
 convex curve.  – A change in the angle of inclination of a belt conveyor where the  center of the curve is below the 
conveyor. [2.21]  
 conveyor stringers.  – Support members for the conveyor on which the scale and idlers are mounted. [2.21]  
 correct.  – A piece of equipment is “correct” when, in addition to being accurate, it meets all app licable specification 
requirements.  Equipment that fails to meet any of the requirements for correct equipment is “incorrect.”  (Also see  “accurate.”) [Appendix A]  Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
  
correction table.  – Any table, graph, slide rule, or other external device used to determ ine the moisture content 
from the value indicated by the moisture meter when the indicated value is altered by a parameter not automatically corrected for in the moisture meter (for example, temperature or test weight). [5.56(b)]  
 counterbalance weight(s).  – One intended for application near the butt of a weighbeam for zero -load balancing 
purposes. [2.20]  
 
counterpoise weight(s).  – A slotted or “hanger” weight intended for application near the tip of the weighbeam of a 
scale having a multiple greater than one. [2.20]  
 
coupled- in-motion railroad weighing system.  – A device and related installation characteristics consisting of 
(1) the associated approach trackage, (2)  the scale (i.e., the weighing element, the load -receiving element, and the 
indicating eleme nt with its software), and (3)  the exit trackage, which permit the weighing of railroad cars coupled 
in motion. [2.20, 2.23]  
(Added 1992)  
 crane scale.  – One with a nominal capacity of 5000  pounds or more designed to weigh loads while they are 
suspended fr eely from an overhead, track -mounted crane. [2.20]  
 cryogenic liquid -measuring device.  – A system including a liquid -measuring element designed to measure and 
deliver cryogenic liquids in the liquid state. [3.34]  
(Amended 1986 and 2003)  
 
cryogenic liquids.  – Fluids whose normal boiling point is below 120 kelvin (−  243 °F). [3.34]  
 cubic foot, gas.  – The amount of a cryogenic liquid in the gaseous state at a temperature of 70  °F and under a 
pressure of 14.696 lb/in
2 absolute that occupies one cubic foot (1  ft3).  (See NTP.) [3.34]  
D 
“d,” dimension division value.  – The smallest increment that the device displays for any axis and length of object in that 
axis. [5.58]  
 
d, value scale division.  – See “scale division, va lue of (d).” [2.20, 2.22]  
 
Dmax (maximum load of the measuring range).  – Largest value of a quantity (mass) which is applied to a load cell 
during test or use.  This value shall not be greater than Emax. [2.20]   
(Added 2005)  
 
Dmin (minimum load of the measuring range).  – Smallest value of a quantity (mass) which is applied to a load cell 
during test or use.  This value shall not be less than Emin. [2.20]  
(Added 2006)  
 
dairy -product -test scale.  – A scale used in determining the moisture content of butter and/or cheese or in 
determining the butterfat content of milk, cream, or butter. [2.20]  
 
decimal submultiples.  – Parts obtained by successively dividing by the number  10.  Thus 0.1, 0.01, 0.001, a nd so 
on are decimal submultiples. [1.10]  
 
decreasing -load test.  – A test for automatic -indicating scales only, wherein the performance of the scale is tested as 
the load is reduced. [2.20, 2.22]  
(Amended 1987)  
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 deficiency.  – See “excess and deficiency.” [ 1.10]  
 
 
diesel gallon equivalent (DGE). –  means 2.821 kg (6.22 lb) of natural gas.  [5.2] 
(Added 2013)  
 
diesel liter equivalent (DLE).  –  means 0.756 kg of natural gas.  [5.2] 
(Added 2013)  
 
digital type.  – A system of indication or recording of the selector type or one that advances intermittently in which 
all values are presented digitally, or in numbers.  In a digital indicating or recording element, or in digital 
representation, there are no graduations.  [1.10]  
 
dimensional weight (or dim, weight).  – A value computed by dividing the object’s volume by a conversion factor; 
it may be used for the calculation of charges when the value is greater than the actual weight. [5.58]  
(Added 2004)  
 
direct sale.  – A sale in which both parties in the transaction are present when the quantity is being determined.  An 
unattended automated or customer -operated weighing or measuring system is considered to represent the 
device/business owner in transactions involving an unattended device. [1.10]  
(Amended 1993)  
 
discharge hose.  – A flexible hose connected to the discharge outlet of a measuring device or its discharge line. 
[3.30, 3.31, 3.32, 3.34, 3.37, 3.38]  
(Added 1987)  
 
discharge line.  – A rigid pipe connected to the outlet of a measuring device. [3.30, 3.31, 3.32, 3.34, 3.37]  
(Added 1987)  
 
discrimination (of an automatic -indicating scale).  – The value of the test load on the load -receiving element of 
the scale that will produce a specifi ed minimum change of the indicated or recorded value on the scale. [2.20, 2.22]  
 
dispenser.  – See motor -fuel device. [3.30, 3.37]  
 distributed- car test train.  – A train consisting of cars weighed first on a reference scale, cars coupled consecutively 
in gr oups at different locations within the train, then run over the coupled -in-motion railway track scale under test.  
The groups are typically placed at the front, middle, and rear of the train. [2.20]  
(Added 1990)  
 dry hose.  – A discharge hose intended to be  completely drained at the end of each delivery of product.  (Also see 
“dry-hose type.”) [3.30, 3.31]  
(Amended 2002)  
 
dry-hose type.  – A type of device in which it is intended that the discharge hose be completely drained following 
the mechanical operations involved in each delivery.  (Also see “dry hose.”) [3.30, 3.31, 3.34, 3.35]  
 
dynamic monorail weighing system . – A weighing system w hich employs hardware or software to compensate for 
dynamic effects from the load or the system that do not exist in static weighing, in order to provide a stable indication.  Dynamic factors may include shock or impact loading, system vibrations, oscillations, etc., and can 
occur even when the load is not moving across the load -receiving element. [2.20]  
(Added 1999)  
E 
e, value of verification scale division.  – See “verification scale division, value of (e).” [2.20]  Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
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Emax (maximum capacity).  – Largest value  of a quantity (mass) which may be applied to a load cell without 
exceeding the mpe. [2.20]  
(Added 2005)  
Emin (minimum dead load).  – Smallest value of a quantity (mass) which may be applied to a load cell during test or 
use without exceeding the mpe. [2.20 ] 
(Added 2006)  
emin (minimum verification scale division).  – The smallest scale division for which a weighing element complies 
with the applicable requirements. [2.20, 2.21, 2.24]  
(Added 1997)  
 electronic link.  – An electronic connection between the weighi ng/load -receiving or other sensing element and 
indicating element where one recognizes the other and neither can be replaced without calibration. [2.20]  
(Added 2001)  
 
element.  – A portion of a weighing or measuring device or system which performs a specific function and can be 
separated, evaluated separately, and is subject to specified full or partial error limits.  
(Added 2002)  
 
equal -arm scale.  – A scale having only a single lever with equal arms (that is, with a multiple of one), equipped 
with two  similar or dissimilar load -receiving elements (pan, plate, platter, scoop, or the like), one intended to receive 
material being weighed and the other intended to receive weights.  There may or may not be a weighbeam. [2.20]  
 
equipment, commercial.  – Weights, measures, and weighing and measuring devices, instruments, elements, and 
systems or portion thereof, used or employed in establishing the measurement or in computing any basic charge or 
payment for services rendered on the basis of weight or measure.  As used in this definition, measurement includes 
the determination of size, quantity, value, extent, area, composition (limited to meat and poultry), constituent value 
(for grain), or measurement of quantities, things, produce, or articles for distribution  or consumption, purchased, 
offered, or submitted for sale, hire, or award. [1.10, 2.20, 2.21, 2.22, 2.24, 3.30, 3.31, 3.32, 3.33, 3.34, 3.35, 3.38, 
4.40, 5.51, 5.56.(a), 5.56.(b), 5.57, 5.58, 5.59]  
(Added 2008)  
 event counter.  – A non -resettable counter t hat increments once each time the mode that permits changes to sealable 
parameters is entered and one or more changes are made to sealable calibration or configuration parameters of a 
device. [2.20, 2.21, 3.30, 3.37, 5.54, 5.56(a), 5.56(b), 5.57]  
(Added 1993)  
 
event logger.  – A form of audit trail containing a series of records where each record contains the number from the event 
counter corresponding to the change to a sealable parameter, the identification of the parameter that was changed, the time 
and d ate when the parameter was changed, and the new value of the parameter. [2.20, 2.21, 3.30, 3.37, 5.54, 5.56(a), 
5.56(b), 5.57]  
(Added 1993)  
 
excess and deficiency . – When an instrument or device is of such a character that it has a value of its own that ca n 
be determined, its error is said to be “in excess” or “in deficiency,” depending upon whether its actual value is, 
respectively, greater or less than its nominal value.  (Also see “nominal.”)  Examples of instruments having errors 
“in excess” are:  a lin ear measure that is too long; a liquid measure that is too large; and a weight that is “heavy.”  
Examples of instruments having errors “in deficiency” are:  a lubricating -oil bottle that is too small; a vehicle tank 
compartment that is too small; and a wei ght that is “light.” [1.10]  
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 extras.  – Charges to be paid by a passenger in addition to the fare, including any charge at a flat rate for the 
transportation of passengers in excess of a stated number and any charge for the transportation of baggage. [5.54]  
F 
face.  – That side of a taximeter on which passenger charges are indicated. [5.54]  
 
face. – That portion of a computing- type pump or dispenser which displays the actual computation of price per unit, 
delivered quantity, and total sale price.  In the case of some electronic displays, this may not be an integral part of 
the pump or dispenser. [3.30]  
(Added 1987)  
 
fare.  – That portion of the charge for the hire of a vehicle that is automatically calculated by a taximeter through the 
operation of the distance  and/or time mechanism. [5.54]  
 
farm milk tank.  – A unit for measuring milk or other fluid dairy product, comprising a combination of (1)  a 
stationary or portable tank, whether or not equipped with means for cooling its contents, (2)  means for reading the 
level of liquid in the tank, such as a removable gauge rod or a surface gauge, and (3)  a chart for converting 
level -of-liquid readings to volume; or such a unit in which readings are made on a gauge rod or surface gauge 
directly in terms of volume.  Each compartment of a subdivided tank shall, for purposes of this code, be construed to 
be a “farm milk tank.” [4.43]  
 
feeding mechanism . – The means for depositing material to be weighed on the belt conveyor. [2.21]  
 
fifth wheel.  – A commercially -available distance -measuring device which, after calibration, is recommended for use 
as a field transfer standard for testing the accuracy of taximeters and odometers on rented vehicles. [5.53, 5.54]  
 
fifth-wheel test.  – A distance test similar to a road test, except th at the distance traveled by the vehicle under test is 
determined by a mechanism known as a “fifth wheel” that is attached to the vehicle and that independently measures 
and indicates the distance. [5.53, 5.54]  
 
flag.  – A plate at the end of the lever arm o r similar part by which the operating condition of a taximeter is 
controlled and indicated. [5.54]  
 fractional bar.  – A weighbeam bar of relatively small capacity for obtaining indications intermediate between 
notches or graduations on a main or tare bar. [2.20]  
 
ft
3/h. – Cubic feet per hour. [3.33]  
G 
gasoline gallon equivalent (GGE).  – Gasoline gallon equivalent (GGE) means 5.660  pounds of natural gas. [3.37]  
(Added 1994)  
 gasoline liter equivalent (GLE).  – Gasoline liter equivalent (GLE) means 0.678  kilograms of natural gas. [3.37]  
(Added 1994)  
 
gauge pressure.  – The difference between the pressure at the meter and the atmospheric pressure (psi). [3.33]  
 gauge rod.  – A graduated, “dip -stick” type of measuri ng rod designed to be partially immersed in the liquid and to 
be read at the point where the liquid surface crosses the rod. [4.42]  
 gauging.  – The process of determining and assigning volumetric values to specific graduations on the gauge or 
gauge rod tha t serve as the basis for the tank volume chart. [4.42]  Handbook 44 – 2015 2016  Appendix D –  Definitions  
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graduated interval.  – The distance from the center of one graduation to the center of the next graduation in a series 
of graduations. –  (Also see “value of minimum graduated interval.”) [1.10]  
 
gradua tion.  – A defining line or one of the lines defining the subdivisions of a graduated series.  The term includes 
such special forms as raised or indented or scored reference “lines” and special characters such as dots.  (Also see 
“main graduation” and “subo rdinate graduation.”) [1.10]  
 
grain class.  – Different grains within the same grain type.  For example, there are six classes for the grain type 
“wheat:”  Durum Wheat, Hard Red Spring Wheat, Hard Red Winter Wheat, Soft Red Winter Wheat, Hard White 
Wheat, and Soft White Wheat. [5.56(a), 5.57]  
(Added 2007)  
 
grain hopper scale.  – One adapted to the weighing of individual loads of varying amounts of grain. [2.20]  
 
grain moisture meter.  – Any device indicating either directly or through conversion tables and/or correction tables 
the moisture content of cereal grains and oil seeds.  Also termed “moisture meter.” [5.56(a), 5.56(b)]  
 grain sample.  – That portion of grain or seed taken from a bulk quantity of grain or seed to be bought or sold and 
used to determine the moisture content of the bulk. [5.56(a), 5.56(b)]  
 grain -test scale.  – A scale adapted to weighing grain samples used in determining moisture content, dockage, 
weight per unit volume, etc. [2.20]  
 
grain type.  – See “kind of grain.” [5.56(a), 5.57]  
(Added 2007)  
 
gravity discharge.  – A type of device designed for discharge by gravity. [3.30, 3.31]  
H 
head pulley.  – The pulley at the discharge end of the belt conveyor.  The power drive to drive the belt is generally 
applied to the head pulley. [2.21]  
 
hexahedron.  – A geometric solid (i.e., box) with six rectangular or square plane surfaces. [5.58]  
(Added 2008)  
 
hired.  – A taximeter is “hired” when it is operative with respect to all applicable indications of fare or extras.  The 
indications of fare include time and distance where applicable unless qualified by another indication of “Time Not Recording” or an equivalent expression. [5.54]  
 hopper scale.  – A scale designed for weighing bulk commodities whose load -receiving element is a tank, box, or 
hopper mounted on a  weighing element.  (Also see “automatic hopper scale,” “grain hopper scale,” and 
“construction materials hopper scale.”) [2.20]  
I 
idler space.  – The center -to-center distance between idler rollers measured parallel to the belt. [2.21]  
 
idlers or idler rol lers. – Freely turning cylinders mounted on a frame to support the conveyor belt.  For a flat belt, 
the idlers consist of one or more horizontal cylinders transverse to the direction of belt travel.  For a troughed belt, the idlers consist of one or more h orizontal cylinders and one or more cylinders at an angle to the horizontal to lift 
the sides of the belt to form a trough. [2.21]  
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 in-service light indicator.  – A light used to indicate that a timing device is in operation. [5.55]  
 
increasing -load test.  – The normal basic performance test for a scale in which observations are made as increments 
of test load are successively added to the load -receiving element of the scale. [2.20, 2.22]  
 
increment.  – The value of the smallest change in value that can be ind icated or recorded by a digital device in 
normal operation. [1.10]  
 
index of an indicator.  – The particular portion of an indicator that is directly utilized in making a reading. [1.10]  
 indicating element . – An element incorporated in a weighing or measuring device by means of which its 
performance relative to quantity or money value is “read” from the device itself as, for example, an index -and-graduated -scale combination, a weighbeam -and-poise combination, a digital indicator, and the like.  
(Also see “primary indicating or recording element.”) [1.10]  
 indicator, balance.  – See “balance indicator.” [2.20]  
 
initial distance or time interval.  – The interval corresponding to the initial money drop. [5.54]  
 
initial zero -setting mechanism.  – See “initial zero -setting mechanism” under “zero -setting mechanism.” [2.20]  
(Added 1990)  
 integrator. – A device used with a belt -conveyor scale that combines conveyor belt load (e.g., lb/ft) and belt travel 
(e.g., feet) to pr oduce a total weight of material passing over the belt -conveyor scale.  An integrator may be a 
separate, detached mechanism or may be a component within a totalizing device.  (Also see “master weight totalizer.”) [2.21]  
(Added 2013)  
 
interval, clear, between graduations.  – See “clear interval between graduations.” [1.10]  
 
interval, graduated.  – See “graduated interval.” [1.10]  
 irregularly -shaped object.  – Any object that is not a hexahedron shape. [5.58]  
(Added 2008)  
J 
jewelers’ scale.  – One adapted to weighing gems and precious metals. [2.20]  
 
K 
kind of grain.  – Corn as distinguished from soybeans as distinguished from wheat, etc. [5.56(a), 5.56(b)]  
L 
label.  – A printed ticket, to be attached to a package, produced by a printer that is a part of a prepackaging scale or 
that is an auxiliary device. [2.20]  
 
large -delivery device.  – Devices used primarily for single deliveries greater than 200  gallons, 2000 pounds, 
20 000 cubic feet, 2000  liters, or 2000  kilograms. [3.34, 3.38]  
 
laundry -drier timer.  – A timer used in conjunction with a coin -operated device to measure the period of time that a 
laundry drier is in operation. [5.55]  
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 liquefied petroleum gas.  – A petroleum product composed predominantly of any of the following hydrocarbons or 
mixtures thereof:  propane, propylene, butanes (normal butane or isobutane), and butylenes. [3.31, 3.32, 3.33, 3.34, 
3.37]  
 
liquefied petroleum gas liquid- measuring device.  – A system including a mechanism or machine of the meter type 
designed to measure and deliver liquefied petroleum gas in the liquid state by a definite quantity, whether installed 
in a permanent location or mounted on a vehicle.  Means may or may not be provided to indicate automatically, for 
one of a series of unit prices, the total money value of the liquid measured. [3.33]  
(Amended 1987)  
 liquefied petroleum gas vapor -measuring device.  – A system including a mechanism or device of the meter type, 
equipped with a totalizing index, designed to measure and deliver liquefied petroleum gas in the vapor state by 
definite volumes, and generally installed in a permanent location.  The meters are similar in construction and 
operation to the conventional natural - and manufactured -gas meters. [3.33]  
 
liquid fuel.  – Any liquid used for fuel purposes, that is, as a fuel, including motor -fuel. [3.30, 3.31]  
 liquid volume correction factor.  – A correction factor used to adjust the liquid volume of a cryogenic product at 
the time of measurement to the liquid volume at NB P. [3.34]  
 
liquid- fuel device.  – A device designed for the measurement and delivery of liquid fuels. [3.30]  
 
liquid- measuring device.  – A mechanism or machine designed to measure and deliver liquid by definite volume.  
Means may or may not be provided to indicate automatically, for one of a series of unit prices, the total money value of the liquid measured, or to make deliveries correspo nding to specific money values at a definite unit price. [3.30]  
 livestock scale.  – A scale equipped with stock racks and gates and adapted to weighing livestock standing on the 
scale platform. [2.20]  
(Amended 1989)  
 
load cell.  – A device, whether electric, hydraulic, or pneumatic, that produces a signal (change in output) 
proportional to the load applied. [2.20, 2.21, 2.23]  
 
load cell verification interval (v).  – The load cell interval, expressed in units of mass, used in the test of the load 
cell for accu racy classification. [2.20, 2.21]  
(Added 1996)  
 
loading point.  – A location on a conveyor where the material is received by the belt.   The location of the discharge 
from a hopper, chute, or pre -feed device used to supply material to a conveyor . [2.21]  
(Ame nded 2013)  
 
load-receiving element.  – That element of a scale that is designed to receive the load to be weighed; for example, 
platform, deck, rail, hopper, platter, plate, scoop. [2.20, 2.21, 2.23]  
 
low-flame test.  – A test simulating extremely low -flow r ates such as caused by pilot lights. [3.33]  
 lubricant device.  – A device designed for the measurement and delivery of liquid lubricants, including, but not 
limited to, heavy gear lubricants and automatic transmission fluids (automotive). [3.30]  
M 
m3/h. – Cubic meters per hour.[3.33]  
 
main bar.  – A principal weighbeam bar, usually of relatively large capacity as compared with other bars of the same 
weighbeam.  (On an automatic -indicating scale equipped with a weighbeam, the main weighbeam bar is frequently  
called the “capacity bar.”) [2.20]    Handbook 44 – 2015 2016  
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main graduation.  – A graduation defining the primary or principal subdivisions of a graduated series.  (Also see 
“graduation.”) [1.10]  
 
main -weighbeam elements.  – The combination of a main bar and its fractional bar, or  a main bar alone if no 
fractional bar is associated with it. [2.20]  
 manual zero -setting mechanism . – See “manual zero -setting mechanism” under “zero -setting mechanism.” [2.20]  
 manufactured device.  – Any commercial weighing or measuring device shipped as  new from the original 
equipment manufacturer. [1.10]  
(Amended 2001)  
 mass flow meter.  – A device that measures the mass of a product flowing through the system.  The mass 
measurement may be determined directly from the effects of mass on the sensing unit or may be inferred by measuring the properties of the product, such as the volume, density, temperature, or pressure, and displaying the 
quantity in mass units. [3.37]  
 master meter test method.  – A method of testing milk tanks that utilizes an approved ma ster meter system for 
measuring test liquid removed from or introduced into the tank. [4.42]  
 master weight totalizer.  – A primary indicating element used with a belt -conveyor scale that incorporates the 
function of an integrator to indicate the totalized weight of material passed over the scale.  (Also see “integrator.”) 
[2.21]  
(Amended 2013)  
 
material test.  – The test of a belt- conveyor scale using material (preferably that for which the device is normally 
used) that has been weighed to an accuracy of 0.1  %. [2.21]  
(Amended 1989)  
 maximum capacity.  – The largest load that may be accurately weighed. [2.20, 2.24 ] 
(Added 1999)  
 maximum cargo load.  – The maximum cargo load for trucks is the difference between the manufacturer’s rated 
gross vehicle weight and the actual weight of the vehicle having no cargo load. [5.53]  
 measurement field.  – A region of space or the measurement pattern produced by the measuring instrument in which 
objects are placed or passed through, either singly or in groups, when being measured by a single device. [5.58]  
 measuring element.  – That portion of a complete multiple dimension measurin g device that does not include the 
indicating element. [5.58]  
 
meter register.  – An observation index for the cumulative reading of the gas flow through the meter.  In addition 
there are one or two proving circles in which one revolution of the test hand r epresents ½, 1, 2, 5, or 10 cubic feet, or 
0.025, 0.05, 0.1, 0.2, or 0.25 cubic meter, depending on meter size.  If two proving circles are present, the circle 
representing the smallest volume per revolution is referred to as the “leak -test circle.” [3.33]  
 
metrological integrity (of a device).  – The design, features, operation, installation, or use of a device that facilitates 
(1) the accuracy and validity of a measurement or transaction, (2)  compliance of the device with weights and 
measures requirements,  or (3) the suitability of the device for a given application. [1.10, 2.20]  
(Added 1993)  
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 minimum capacity.  – The smallest load that may be accurately weighed.  The weighing results may be subject to 
excessive error if used below this value. [2.20, 2.24]  
(Added 1999)  
 
minimum clear interval . – The shortest distance between adjacent graduations when the graduations are not 
parallel.  (Also see “clear interval.”) [3.30, 3.31, 3.32, 3.33, 3.34, 3.35, 3.36, 3.38, 5.50, 5.51, 5.56(b)]  
 
minimum delivery.  – The le ast amount of weight that is to be delivered as a single weighment by a belt -conveyor 
scale system in normal use. [2.21]  
 minimum tolerance.  – Minimum tolerances are the smallest tolerance values that can be applied to a scale.  
Minimum tolerances are determined on the basis of the value of the minimum graduated interval or the nominal or 
reading face capacity of the scale.  (Also see definition  for basic tolerances.) [2.20, 2.22, 2.24]  
 
minimum totalized load.  – The least amount of weight for which the scale is considered to be performing 
accurately. [2.21]  
 
moisture content (wet basis).  – The mass of water in a grain or seed sample (determined by the reference method) 
divided by the mass of the grain or seed sample expressed as a percentage (%). [5.56(a), 5.56(b)]  
 money drop.  – An increment of fare indication.  The “initial money drop” is the first increment of fare indication 
following activation of the taximeter. [5.54]  
 
money -operated type.  – A device designed to be released for service by the insertion of money, or to be actuated 
by the insertion of money to make deliveries of product. [1.10]  
 motor -fuel. – Liquid used as fuel for internal -combustion engines. [3.30]  
 motor -fuel device or motor- fuel dispenser or retail motor- fuel device.  – A device designed for the measurement 
and delivery of liquids used as fuel for internal -combustion engines.  The term “mo tor-fuel dispenser” means the 
same as “motor -fuel device”; the term “retail motor -fuel device” applies to a unique category of device.  (Also see 
definition of “retail device.”) [3.30, 3.32, 3.37]  
 multi -class.  – A description of a grouping of grain classe s, from the same grain type, in one calibration.  A 
multi -class grain calibration may include (1)  all the classes of a grain type (all -class calibration), or (2)  some of the 
classes of a grain type within the calibration. [5.56(a), 5.57.]  
(Added 2007)  
 multi-interval scale.  – A scale having one weighing range which is divided into partial weighing ranges (segments), 
each with different scale intervals, with each partial weighing range (segment) determined automatically according to the load applied, both on  increasing and decreasing loads. [2.20]  
(Added 1995)  
 multi -jet water meter.  – A water meter in which the moving element takes the form of a multiblade rotor mounted 
on a vertical spindle within a cylindrical measuring chamber.  The liquid enters the meas uring chamber through 
several tangential orifices around the circumference and leaves the measuring chamber through another set of tangential orifices placed at a different level in the measuring chamber.  These meters register by recording the 
revolutions  of a rotor set in motion by the force of flowing water striking the blades. [3.36]  
(Added 2003)  
 
multi -revolution scale.  – An automatic -indicating scale having a nominal capacity that is a multiple of the 
reading -face capacity and that is achieved by more than one complete revolution of the indicator. [2.20]  
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 multiple.  – An integral multiple; that is, a result obtained by multiplying by a whole number.  (Also see “multiple of 
a scale.”) [1.10]  
 
multiple cell application load cell.  – A load cell intended fo r use in a weighing system which incorporates more 
than one load cell.  A multiple cell application load cell is designated with the letter “M” or the term “Multiple.”  
(Also see “single cell application load cell.”) [2.20]  
(Added 1999)  
 
multiple of a scale.  – In general, the multiplying power of the entire system of levers or other basic weighing 
elements.  (On a beam scale, the multiple of the scale is the number of pounds on the load -receiving element that 
will be counterpoised by one  pound applied to th e tip pivot of the weighbeam.) [2.20]  
 
multiple range scale.  – A scale having two or more weighing ranges with different maximum capacities and 
different scale intervals for the same load receptor, each range extending from zero to its maximum capacity. [2 .20] 
(Added 1995)  
 
multiple -tariff taximeter.  – One that may be set to calculate fares at any one of two or more rates. [5.54]  
 
N 
 natural gas.  – A gaseous fuel, composed primarily of methane, that is suitable for compression and dispensing into 
a fuel sto rage container(s) for use as an engine fuel. [3.37]  
(Added 1994)  
 
NBP.  – Normal Boiling Point of a cryogenic liquid at 14.696  lb/in
2 absolute. [3.34]  
 
nmax (maximum number of scale divisions).  – The maximum number of scale divisions for which a main element 
or load cell complies with the applicable requirements.  The maximum number of scale divisions permitted for an 
installation is limited to the lowest n max marked on the scale indicating elemen t, weighing element, or load cell. 
[2.20, 2.21, 2.24]  
(Added 1997)  
 
no-load reference value.  – A positive weight value indication with no load in the load -receiving element (hopper) 
of the scale.  (Used with automatic bulk -weighing systems and certain single -draft, manually- operated receiving 
hopper scales installed below grade and used to receive grain.) [2.20]  
 
nominal.  – Refers to “intended” or “named” or “stated,” as opposed to “actual.”  For example, the “nominal” value of 
something is the value th at it is supposed or intended to have, the value that it is claimed or stated to have, or the value by 
which it is commonly known.  Thus, “1 -pound weight,” “1 -gallon measure,” “1 -yard indication,” and “500 -pound scale” 
are statements of nominal values; cor responding actual values may be greater or lesser.  (Also see nominal capacity of a 
scale.) [1.10]  
 
nominal capacity.  – The nominal capacity of a scale is (a)  the largest weight indication that can be obtained by the 
use of all of the reading or recording elements in combination, including the amount represented by any removable 
weights furnished or ordinarily furnished wi th the scale, but excluding the amount represented by any extra 
removable weights not ordinarily furnished with the scale, and excluding also the capacity of any auxiliary weighing 
attachment not contemplated by the original design of the scale, and exclud ing any fractional bar with a capacity less 
than 2½  % of the sum of the capacities of the remaining reading elements, or (b)  the capacity marked on the scale by 
the manufacturer, whichever is less.  (Also see “nominal capacity, batching scale”; “nominal capacity, hopper 
scale.”) [2.20]  
 Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 nominal capacity, batching scale.  – The nominal capacity of a batching scale is the capacity as marked on the scale 
by the scale manufacturer, or the sum of the products of the volume of each of the individual hoppers, in te rms of 
cubic feet, times the weight per cubic foot of the heaviest material weighed in each hopper, whichever is less. [2.20]  
 
nominal capacity, hopper scale.  – The nominal capacity of a hopper scale is the capacity as marked on the scale by 
the scale manu facturer, or the product of the volume of the hopper in bushels or cubic feet times the maximum 
weight per bushel or cubic foot, as the case may be, of the commodity normally weighed, whichever is less. [2.20]  
 
non- automatic checkweigher.  – A weighing inst rument that requires the intervention of an operator during the weighing 
process, used to subdivide items of different weights into one or more subgroups, such as identifying packages that have 
acceptable or unacceptable fill levels according to the value of the difference between their weight and a pre -determined set 
point. [2.24]  
 
Notes:  Determining the weighing result includes any intelligent action of the operator that affects the result, 
such as deciding and taking an action when an indication is stable or adjusting the weight of the weighed load.  
 
Deciding the weighing result is acceptable means making a decision regarding the acceptance of each weighing 
result on observing the indication or releasing a print -out.  The weighing process allows the operator to take an 
action which influences the weighing result in the case where the weighing result is not acceptable.  
(Added 2004)  
 
non- automatic weighing instrument.  – A weighing instrument or system that requires the intervention of an 
operator during  the weighing process to determine the weighing result or to decide that it is acceptable. [2.20, 2.24]  
 
Notes:  Determining the weighing result includes any intelligent action of the operator that affects the result, 
such as deciding and taking an action when an indication is stable or adjusting the weight of the weighed load.  
 
Deciding the weighing result is acceptable means making a decision regarding the acceptance of each weighing 
result on observing the indication or releasing a print -out.  The weighing process allows the operator to take an 
action which influences the weighing result in the case where the weighing result is not acceptable.  
(Added 2004) (Amended 2005)  
 
nonretroactive.  – “Nonretroactive” requirements are enforceable after the effective date for:  
 
1. devices manufactured within a state after the effective date;  
 
2. both new and used devices brought into a state after the effective date; and  
 
3. devices used in noncommercial applications which are placed into commercial use after the effective date.  
 
Nonretroactive requirements are not enforceable with respect to devices that are in commercial service in the state as 
of the effective date or to new equipment in the stock of a manufacturer or a dealer in the state as of the effective 
date.  (Nonretroactive requirements are printed in italic type.) [1.10]  
(Amended 1989)  
 
nose -iron.  – A slide -mounted, manually -adjustable pivot assembly for changing the multiple of a lever. [2.20]  
 notes.  – A section included in each of a number of codes, containing instructions, pertinent directives, and other 
specific information pertaining to the testing of devices.  Notes are primarily directed to weights and measures 
officials.  
 
NTP.  – Normal Temperature and Pressure of a cryogen at a temperature of 21  °C (70  °F) and a pressure of 
101.325 kPa (14.696  lb/in
2 absolute). [3.34]  
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 NTP density and volume correction factor.  – A correction factor used to adjust the liquid volume of a cryogenic 
product at the time of measurement to the gas equivalent at NTP. [3. 34] 
O 
odometer.  – A device that automatically indicates the total distance traveled by a vehicle.  For the purpose of this 
code, this definition includes hub odometers, cable -driven odometers, and the distance -indicating or odometer 
portions of “speedometer” assemblies for automotive vehicles. [5.53]  
 
official grain samples . – Grain or seed used by the official as the official transfer standard from the reference 
standard method to test the accuracy and precision of grain moisture meters. [5.56(a ), 5.56(b)]  
 
official with statutory authority.  – The representative of the jurisdiction(s) responsible for certifying the accuracy 
of the device. [2.20, 2.21, 2.22]  
(Added 1991)  
 
operating tire pressure.  – The pressure in a tire immediately after a vehicl e has been driven for at least 5  miles or 
8 kilometers. [5.53, 5.54]  
 
over -and- under indicator.  – An automatic -indicating element incorporated in or attached to a scale and comprising 
an indicator and a graduated scale with a central or intermediate “zero” graduation and a limited range of weight 
graduations on either side of the zero graduation, for indicating weights greater than and less than the predetermined values for which other elements of the scale may be set.  (A scale having an over -and-under ind icator is classed as 
an automatic -indicating scale.) [2.20]  
 
overregistration and underregistration.  – When an instrument or device is of such a character that it indicates or 
records values as a result of its operation, its error is said to be in the direction of overregistration or underregistration, depending upon whether the indications are, respectively, greater or less than they should be.  
Examples of devices having errors of “overregistration” are:  a fabric- measuring device that indicates more than the 
true length of material passed through it; and a liquid -measuring device that indicates more than  the true amount of 
the liquid delivered by the device.  Examples of devices having errors of “underregistration” are:  a meter that indicates less than the true amount of product that it delivers; and a weighing scale that indicates or records less than the true weight of the applied load. [1.10]  
 
P 
parallax.  – The apparent displacement, or apparent difference in height or width, of a graduation or other object 
with respect to a fixed reference, as viewed from different points. [1.10]  
 parking meter.  – A coin-operated device for measuring parking time for vehicles. [5.55]  
 
passenger vehicles.  – Vehicles such as automobiles, recreational vehicles, limousines, ambulances, and hearses. 
[5.53]  
 
performance requirements.  – Performance requirements include all to lerance requirements and, in the case of 
nonautomatic -indicating scales, sensitivity requirements (SR).  (Also see definitions for “tolerance” and “sensitivity 
requirement.”) [1.10]  
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 point -of-sale system.  – An assembly of elements including a weighing or measuring element, an indicating element, 
and a recording element (and may also be equipped with a “scanner”) used to complete a direct sales 
transaction .[2.20, 3.30, 3.32, 3.37] .  The system components, whe n operated together, must be capable of the 
following:  
 
1. determining the weight or measure of a product or service offered;  
 
2. calculating a charge for the product or service based on the weight or measure and an established price/rate 
structure;  
 
3. determining  a total cost that includes all associated charges involved with the transaction; and  
 
4. providing a sales receipt.  
[2.20, 3.30, 3.32, 3.37]  
(Added 1986) (Amended 1997 and 2015)  
 
poise.  – A movable weight mounted upon or suspended from a weighbeam bar and us ed in combination with 
graduations, and frequently with notches, on the bar to indicate weight values.  (A suspended poise is commonly called a “hanging poise.”) [2.20]  
 
postal scale.  – A scale (usually a computing scale) designed for use to determine ship ping weight or delivery 
charges for letters or parcels delivered by the U.S. Postal Service or private shipping companies.  A weight classifier may be used as a postal scale. [2.20]  
(Added 1987)  
 
prepackaging scale.  – A computing scale specially designed f or putting up packages of random weights in advance 
of sale. [2.20]  
 
prescription scale.  – A scale or balance adapted to weighing the ingredients of medicinal and other formulas 
prescribed by physicians and others and used or intended to be used in the ordinary trade of pharmacists. [2.20]  
 
pressure type (device).  – A type of device designed fo r operation with the liquid under artificially produced 
pressure. [3.30, 3.31]  
 
primary indicating or recording elements.  – The term “primary” is applied to those principal indicating (visual) 
elements and recording elements that are designed to, or may, b e used by the operator in the normal commercial use 
of a device.  The term “primary” is applied to any element or elements that may be the determining factor in arriving 
at the sale representation when the device is used commercially.  (Examples of primary  elements are the visual 
indicators for meters or scales not equipped with ticket printers or other recording elements and both the visual 
indicators and the ticket printers or other recording elements for meters or scales so equipped.)  The term “primary”  
is not applied to such auxiliary elements as, for example, the totalizing register or predetermined -stop mechanism on 
a meter or the means for producing a running record of successive weighing operations, these elements being 
supplementary to those that a re the determining factors in sales representations of individual deliveries or weights.  
(Also see “indicating element” and “recording element.”) [1.10]  
 
prover method.  – A method of testing milk tanks that utilizes approved volumetric prover(s) for measu ring the test 
liquid removed from or introduced into the tank. [4.42]  
 
prover oil.  – A light oil of low vapor pressure used as a sealing medium in bell provers, cubic -foot bottles, and 
portable cubic -foot standards. [3.33]  
 
proving indicator.  – The test hand or pointer of the proving or leak- test circle on the meter register or index. [3.33, 
3.36.]    Handbook 44 – 2015 2016  
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 R 
“r” factor.  – A computation for determining the suitability of a vehicle scale for weighing vehicles with varying 
axle configurations.  The factor was derived by dividing the weights in FHWA Federal Highway Bridge Gross 
Weight Table  B by 34 000 lbs.  (The resultant factors are contained in Table UR.3.2.1.) [2.20]  
 
radio frequency interference (RFI).  – Radio frequency interference is a type of electri cal disturbance that, when 
introduced into electronic and electrical circuits, may cause deviations from the normally expected performance. [1.10]  
 
random error(s).
 – The sample standard deviation of the error (indicated values) for a number of consecutive  
automatic weighings of a load, or loads, passed over the load receptor, shall be expressed mathematically as:  
 
()()22
21
11
1  or  iX
X
nnXXiinss −
− −
∑= −= ∑ ∑ 
 
where:  X = error of a load indication  
   n = the number of loads  
[2.24]  
 
ranges, weight . – See “weight ranges.” [2.20]  
 rated capacity.
 – The rate of flow in cubic meters per hour of a hydrocarbon gas vapor -measuring device as 
recommended by the manufacturer.  This rate of flow should cause a pressure drop across the meter not exceeding 
½-inch water column. [3.33]  
 
rated scale capacity.  – That value representing the weight that can be delivered by the device in one hour. [2.21]  
 
ratio test.  – A test to determine the accuracy with which the actual multiple of a scale agrees with its designed 
multiple.  This test is used for scales employing counterpoise weights and is made with standard test weights 
substituted in all cases for the weights commercially used on the scale.  (It is appropriate to use this test for some 
scales not employing counterpoi se weights.) [2.20]  
 reading face.
 – That portion of an automatic -indicating weighing or measuring device that gives a visible indication 
of the quantity weighed or measured.  A reading face may include an indicator and a series of graduations or may 
present values digitally, and may also provide money- value indications. [1.10, 2.20]  
(Amended 2005)  
 
reading -face capacity.  – The largest value that may be indicated on the reading face, exclusive of the application or 
addition of any supplemental or acces sory elements. [1.10]  
 recorded representation.  – The printed, embossed, or other representation that is recorded as a quantity by a 
weighing or measuring device. [1.10]  
 
recording element.  – An element incorporated in a weighing or measuring device by means of which its 
performance relative to quantity or money value is permanently recorded on a tape, ticket, card, or the like, in the 
form of a printed, stamped, punched, or perforated representation. [1.10, 2.21]  
 
recording scale.  – One on which the weight s of applied loads may be permanently recorded on a tape, ticket, card, 
or the like in the form of a printed, stamped, punched, or perforated representation. [2.20]  
 
reference weight car.  – A railcar that has been statically weighed for temporary use as a mass standard over a short 
period of time, typically the time required to test one scale.  
 Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 Note :  A test weight car that is representative of the types of cars typically weighed on the scale under test may 
be used wherever reference weight cars are specifi ed. [2.20]  
(Added 1991) (Amended 2012)  
 
remanufactured device.  – A device that is disassembled, checked for wear, parts replaced or fixed, reassembled 
and made to operate like a new device of the same type. [1.10]  
(Added 2001)  
 
remanufactured element.  – An element that is disassembled, checked for wear, parts replaced or fixed, 
reassembled and made to operate like a new element of the same type. [1.10]  
(Added 2001)  
 
remote configuration capability.  – The ability to adjust a weighing or measuring device or change its sealable 
parameters from or through some other device that is not itself necessary to the operation of the weighing or 
measuring device or is not a permanent part of that device. [2.20, 2. 21, 2.24, 3.30, 3.37, 5.56(a)]  
(Added 1993)  
 
repaired device.  – A device to which work is performed that brings the device back into proper operating condition. 
[1.10]  
(Added 2001)  
 
repaired element . – An element to which work is performed that brings the element back into proper operating 
condition. [1.10]  
(Added 2001)  
 
retail device.  – A measuring device primarily used to measure product for the purpose of sale to the end user. [3.30, 
3.32, 3.37]  
(Amended 1987 and 2004)  
 
retroactive.  – “Retroactive” requi rements are enforceable with respect to all equipment.  Retroactive requirements 
are printed herein in upright roman type.  (Also see “nonretroactive.”) [1.10]  
 road test.  – A distance test, over a measured course, of a complete taximeter assembly when installed on a vehicle, 
the mechanism being actuated as a result of vehicle travel. [5.53, 5.54]  
 
rolling circumference.  – The rolling circumference is the straight line distan ce traveled per revolution of the wheel 
(or wheels) that actuates the taximeter or odometer.  If more than one wheel actuates the taximeter or odometer, the 
rolling circumference is the average distance traveled per revolution of the actuating wheels. [5.5 3, 5.54]  
S 
scale.  – See specific type of scale. [2.20]  
 
scale area, belt -conveyor . – See belt -conveyor scale systems area. [2.21]  
(Added 2001)  
 
scale division, number of (n).  – Quotient of the capacity divided by the value of the verification scale divisio n. 
[2.20]  
  
eCapacityn    =  
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 scale division, value of (d).  – The value of the scale division, expressed in units of mass, is the smallest subdivision 
of the scale for analog indication or the difference between two consecutively indicated or printed values for digital 
indication or printing.  (Also see “verificatio n scale division.”) [2.20, 2.22]  
 
scale section.  – A part of a vehicle, axle -load, livestock, or railway track scale consisting of two main load supports, 
usually transverse to the direction in which the load is applied. [2.20]  
 seal. – See “approval seal, ” “security seal.” [1.10]  
 section capacity.  – The section capacity of a scale is the maximum live load that may be divided equally on the load 
pivots or load cells of a section. [2.20]  
(Added 2001)  
 section test.  – A shift test in which the test load is a pplied over individual sections of the scale.  This test is 
conducted to disclose the weighing performance of individual sections, since scale capacity test loads are not always available and loads weighed are not always distributed evenly over all main lo ad supports. [2.20]  
 
security means.  – A method used to prevent access by other than qualified personnel, or to indicate that access has 
been made to certain parts of a scale that affect the performance of the device. [2.21]  
 
security seal.  – A uniquely id entifiable physical seal, such as a lead -and-wire seal or other type of locking seal, a 
pressure -sensitive seal sufficiently permanent to reveal its removal, or similar apparatus attached to a weighing or 
measuring device for protection against or indicati on of access to adjustment.  (Also see “approval seal.”) [1.10]  
(Amended 1994)  
 
selector- type.  – A system of indication or recording in which the mechanism selects, by means of a 
ratchet -and-pawl combination or by other means, one or the other of any two s uccessive values that can be indicated 
or recorded. [1.10]  
 semi -automatic zero -setting mechanism.  – See “semi -automatic zero -setting mechanism” under “zero -setting 
mechanism.” [2.20]  
 sensitivity (of a nonautomatic -indicating scale).  – The value of the test load on the load -receiving element of the 
scale that will produce a specified minimum change in the position of rest of the indicating element or elements of 
the scale. [2.20]  
 
sensitivity requirement (SR).  – A performance requiremen t for a non automatic -indicating scale; specifically, the 
minimum change in the position of rest of the indicating element or elements of the scale in response to the increase 
or decrease, by a specified amount, of the test load on the load -receiving eleme nt of the scale. [2.20]  
 
shift test.  – A test intended to disclose the weighing performance of a scale under off -center loading. [2.20]  
 
side.  – That portion of a pump or dispenser which faces the consumer during the normal delivery of product. [3.30]  
(Added 1987)  
 
simulated -road test.  – A distance test during which the taximeter or odometer may be actuated by some means 
other than road travel.  The distance traveled is either measured by a properly calibrated roller device or computed 
from rolling circ umference and wheel -turn data. [5.53, 5.54]  
 simulated test.  – A test using artificial means of loading the scale to determine the performance of a belt -conveyor 
scale. [2.21]  
 Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 single cell application load cell. –  A load cell intended for use in a weighing  system which incorporates one or 
more load cells.  A single cell application load cell is designated with the letter “S” or the term “Single.”  (Also see 
“multiple cell application load cell.”) [2.20]  
(Added 1999)  
 
single -tariff taximeter. –  One that calc ulates fares at a single rate only. [5.54]  
 skirting. – Stationary side boards or sections of belt conveyor attached to the conveyor support frame or other 
stationary support to prevent the bulk material from falling off the side of the belt. [2.21]  
 slow -flow  meter. –  A retail device designed for the measurement, at very slow rates (less than 40  L (10  gal) per 
hour), of liquid fuels at individual domestic installations. [3.30]  
 small -delivery device. –  Any device other than a large -delivery device. [3.34,  3.38]  
 
span (structural).  The distance between adjoining sections of a scale. [2.20]  
(Added 1988)  
 
specification. – A requirement usually dealing with the design, construction, or marking of a weighing or measuring 
device.  Specifications are directed pr imarily to the manufacturers of devices. [1.10]  
 static monorail weighing system. – A weighing system in which the load being applied is stationary during the 
weighing operation. [2.20]  
(Added 1999)  
 
strain -load test.  – The test of a scale beginning with t he scale under load and applying known test weights to 
determine accuracy over a portion of the weighing range.  The scale errors for a strain -load test are the errors 
observed for the known test loads only.  The tolerances to be applied are based on the k nown test load used for each 
error that is determined. [2.20, 2.22]  
 
subordinate graduation.  – Any graduation other than a main graduation.  (Also see “graduation.”) [1.10]  
 
subsequent distance or time intervals . – The intervals corresponding to money drop s following the initial money 
drop. [5.54]  
 substitution test.  – A scale testing process used to quantify the weight of material or objects for use as a known test load. 
[2.20]  
(Added 2003)  
 substitution test load. –  The sum of the combination of field standard test weights and any other applied load used 
in the conduct of a test using substitution test methods. [2.20]  
(Added 2003)  
 
surface gauge. –  A combination of (1)  a stationary indicator, and (2)  a movable, graduated element designed to be 
brought i nto contact with the surface of the liquid from above. [4.42]  
systematic (average) error 
()X. – The mean value of the error (of indication) for a number of consecutive 
automatic weighings of a load, or loads, passed over the load -receiving element (e.g., weigh -table), shall be 
expressed mathematically as:    Handbook 44 – 2015 2016  
Markup Copy  
Agency No. 209.02 
  
  
 where:  x = error of a load indication  
 n = the number of loads  
 [2.24]  
T 
tail pulley.  – The pulley at the opposite end of the conveyor from the head pulley. [2.21]  
 take-up. – A device to provide sufficient tension in a conveyor belt so that the belt will be positively driven by the 
drive pulley. –  A counter -weighted take -up consists of a pu lley free to move in either the vertical or horizontal 
direction with dead weights applied to the pulley shaft to provide the tension required. [2.21]  
 tare mechanism.  – A mechanism (including a tare bar) designed for determining or balancing out the weight of 
packaging material, containers, vehicles, or other materials that are not intended to be included in net weight 
determinations. [2.20]  
 tare- weighbeam elements.  – The combination of a tare bar and its fractional bar, or a tare bar alone if no fraction al 
bar is associated with it. [2.20]  
 
taximeter.  – A device that automatically calculates, at a predetermined rate or rates, and indicates the charge for 
hire of a vehicle. [5.54]  
 
test chain.  – A device used for simulated tests consisting of a series of r ollers or wheels linked together in such a manner 
as to assure uniformity of weight and freedom of motion to reduce wear, with consequent loss of weight, to a minimum. 
[2.21]  
 
test liquid.  – The liquid used during the test of a device. [3.30, 3.31, 3.34, 3.35, 3.36, 3.37, 3.38]  
 
test object.  – An object whose dimensions are verified by appropriate reference standards and intended to verify 
compliance of the device under test with certain metrological requirements. [5.58]  
 test puck.  – A metal, plastic, or other suitable object that remains stable for the duration of the test, used as a test load to 
simulate a package.  Pucks can be made in a variety of dimensions and have different weights to represent a wide range of package sizes.  M etal versions may be covered with rubber cushions to eliminate the possibility of damage to weighing 
and handling equipment.  The puck mass is adjusted to an accuracy specified in N.1.2. Accuracy of Test Pucks or 
Packages. [2.24]  
(Amended 2004)  
 
test train . – A train consisting of or including reference weight cars and used to test coupled -in-motion railway 
track scales.  The reference weight cars may be placed consecutively or distributed in different places within a train. [2.20]  
(Added 1990) (Amended 1991)  
 test weight car.  – A railroad car designed to be a stable mass standard to test railway track scales.  The test weight 
car may be one of the following types:  a self -contained composite car, a self -propelled car, or a standard rail car. 
[2.20]  
(Added 1991)  
 X
X
n=∑Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 testing.  – An operation consisting of a series of volumetric determinations made to verify the accuracy of the 
volume chart that was developed by gauging. [4.42]  
 
time recorder.  – A clock -operated mechanism designed to record the time of day.  Examples of time recorders are 
those used in parking garages to record the “in” and “out” time of day for parked vehicles. [5.55]  
 
timing device.  – A device used to measure the time during which a particular paid -for service is dispensed.  
Examples of timi ng devices are laundry driers, car -wash timers, parking meters, and parking- garage clocks and 
recorders. [5.55]  
 
tolerance.  – A value fixing the limit of allowable error or departure from true performance or value.  (Also see 
“basic tolerances.”) [1.10]  
 training idlers.  – Idlers of special design or mounting intended to shift the belt sideways on the conveyor to assure 
the belt is centered on the conveying idlers. [2.21]  
 transfer standard.  – A measurement system designed for use in proving and testing cryogenic liquid- measuring 
devices. [3.38]  
 
tripper.  – A device for unloading a belt conveyor at a point between the loading point and the head pulley. [2.21]  
U 
uncoupled- in-motion railroad weighing system.  – A device and related installation characteristics consisting of 
(1) the associated approach trackage, (2)  the scale (i.e., the weighing element, the load -receiving element, and the 
indicating element with its software), and (3)  the exit trac kage, which permit the weighing of railroad cars 
uncoupled in motion. [2.20]  
(Added 1993)  
 
underregistration . – See “overregistration” and “underregistration.” [1.10]  
 unit price.  – The price at which the product is being sold and expressed in whole units of measurement. [1.10, 3.30]  
(Added 1992)  
 
unit train.  – A unit train is defined as a number of contiguous cars carrying a single commodity from one consignor 
to one consignee.  The number of cars is determined by agreement among the consignor, consignee, and the operating railroad. [2.20]  
 
unit weight.  – One contained within the housing of an automatic -indicating scale and mechanically applied to and 
removed from the mechanism.  The application of a unit weight will increase the range of automatic indication, 
normally in increments equal to the reading -face capacity. [2.20]  
 
user requirement.  – A requirement dealing with the selection, installation, use, or maintenance of a weighing or 
measuring device.  User requirements are directed primarily to t he users of devices.  (Also see Introduction, 
Section  Q.) [1.10]  
 usual and customary.  – Commonly or ordinarily found in practice or in the normal course of events and in 
accordance with established practices. [1.10]  
 
utility -type water meter.  – 1) A device used for the measurement of water, generally applicable to meters installed 
in residences or business establishments. excluding batching meters. [3.36]  
(Added 2011)    Handbook 44 – 2015 2016  
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 V 
value of minimum graduated interval . – (1) The value represented by the interval from the center of one 
graduation to the center of the succeeding graduation.  (2) The increment between successive recorded values.  (Also 
see “graduated interval.”) [1.10]  
 
vapor equalization credit.  – The quantity deducted from the metered quantity  of liquid carbon dioxide when a 
vapor equalizing line is used to facilitate the transfer of liquid during a metered delivery. [3.38]  
 
vapor equalization line.  – A hose or pipe connected from the vapor space of the seller’s tank to the vapor space of 
the b uyer’s tank that is used to equalize the pressure during a delivery. [3.38]  
 
vehicle on -board weighing system.  – A weighing system designed as an integral part of or attached to the frame, 
chassis, lifting mechanism, or bed of a vehicle, trailer, industria l truck, industrial tractor, or forklift truck. [2.20]  
(Amended 1993)  
 vehicle scale.  – A scale adapted to weighing highway, farm, or other large industrial vehicles (except railroad 
freight cars), loaded or unloaded. [2.20]  
 
verification scale division, value of  (e). – A value, expressed in units of weight (mass) and specified by the 
manufacturer of a device, by which the tolerance values and the accuracy class applicable to the device are 
determined.  The verification scale division is applied to all scales, in particu lar to ungraduated devices since they 
have no graduations.  The verification scale division (e) may be different from the displayed scale division  (d) for 
certain other devices used for weight classifying or weighing in pre- determined amounts, and certain other Class  I 
and II scales. [2.20]  
 visible type.  – A type of device in which the measurement takes place in a see -through glass measuring chamber. 
[3.30]  
 
v
min (minimum load cell verification interval).  – The smallest load cell verification interval, exp ressed in units of 
mass*  into which the load cell measuring range can be divided. [2.20, 2.24]  
[*Nonretroactive as of January  1, 2001]  
(Added 1996) (Amended 1999)  
W 
weighbeam . – An element comprising one or more bars, equipped with movable poises or means for applying 
counterpoise weights or both. [2.20]  
 
weigh -belt system.  – A type of belt -conveyor scale system designed by the manufacturer as a self -contained 
conveyor system and that is installed as a unit.  A unit is comprised of integral components and, at minimum, 
includes a:  conveyor belt; belt drive; conveyor frame; a nd weighing system.  A weigh- belt system may 
operate at single or multiple flow rates and may use variable -speed belt drives. [2.21]  
(Added 2015)  
 
weighing element. –  That portion of a scale that supports the load -receiving element and transmits to the ind icating 
element a signal or force resulting from the load applied to the load -receiving element. [2.20, 2.21, 2.22]  
(Added 1988)  
 Handbook 44 – 2015 2016  Appendix D –  Definitions  
  Markup Copy  
 Agency No. 209.02  
 weigh -labeler . – An automatic weighing system that determines the weight of a package and prints a label or other 
document bea ring a weight declaration for each discrete item (usually a label also includes unit and total price 
declarations).  Weigh -labelers are sometimes used to weigh and label standard and random packages (also called 
“Prepackaging Scales”). [2.24]  
(Amended 2004)  
 
weigh module  – The portion of a load- receiving element supported by two sections.  The length of a module is the 
distance to which load can be applied. [2.20]  
(Added 2013)  
 
weighment. – A single complete weighing operation. [2.20, 2.21]  
(Added 1986)  
 
weight, unit. –  See “unit weight.” [2.20]  
 
weight classifier. –  A digital scale that rounds weight values up to the next scale division.  These scales usually 
have a verification scale division  (e) that is smaller than the displayed scale division. [2.20]  
(Added 1987)  
 
weight ranges. –  Electrical or electro -mechanical elements incorporated in an automatic indicating scale through the 
application of which the range of automatic indication of the scale is increased, normally in increments equal to the 
reading -face capacity. [2.20]  
 wet basis. –  See “moisture content (wet basis).” [5.56(a), 5.56(b)]  
 
wet hose. –  A discharge hose intended to be full of product at all times.  (Also see “wet -hose type.”) [3.30, 3.31, 
3.38]  
(Amended 2002)  
 
wet-hose type. –  A type of device designed to be operated with the discharge hose full of product at all times.  (Also 
see “wet hose.”) [3.30, 3.32, 3.34, 3.37, 3.38]  
(Amended 2002)  
 wheel -load weighers. – Compact, self -contained, portable weighing elements specially adapted to d etermining the 
wheel loads or axle loads of vehicles on highways for the enforcement of highway weight laws only. [2.20]  
 
wholesale device. –  Any device other than a retail device.  (Also see “retail device.”) [3.30, 3.32]  
 
wing pulley. –  A pulley made of widely spaced metal bars in order to set up a vibration to shake loose material off 
the underside (return side) of the belt. [2.21]  
Z 
zero-load balance . – A correct weight indication or representation of zero when there is no load on the 
load-receiving element.  (Also see “zero -load balance for an automatic -indicating scale,” “zero -load balance for a 
nonautomatic -indicating scale,” “zero -load balance for a recording scale.”) [2.20]  
 
zero-load balance, automatic -indicating scale. –  A condition in which th e indicator is at rest at, or oscillates 
through approximately equal arcs on either side of, the zero graduation. [2.20]  
 
zero-load balance, nonautomatic -indicating scale. –  A condition in which (a)  the weighbeam is at rest at, or 
oscillates through approx imately equal arcs above and below, the center of a trig loop; (b)  the weighbeam or lever 
system is at rest at, or oscillates through approximately equal arcs above and below, a horizontal position or a   Handbook 44 – 2015 2016  
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 position midway between limiting stops; or (c)  the indicator of a balance indicator is at rest at, or oscillates through 
approximately equal arcs on either side of, the zero graduation. [2.20]  
 
zero-load balance for a recording scale. –  A condition in which the scale will record a representation of zero load . 
[2.20]  
 
zero-load reference (belt -conveyor scales).  – A zero -load reference value represents no load on a moving 
conveyor belt.  This value can be either; a number representing the electronic load cell output, a percentage of full scale capacity, or other reference value that accurately represents the no load condition of a moving conveyor belt.  
The no load reference value can only be updated after the completion of a zero load test.[2.21]  
(Added 2002)  
 
zero-setting mechanism.  – Means provided to attain a zero balance indication with no load on the load -receiving 
element.  The types of zero -setting mechanisms are:  [2.20, 2.22, 2.24]  
 
automatic zero -setting mechanism (AZSM). –  Automatic means provided to set the zero -balance indication 
without the intervention of an operator. [2.22]  
(Added 2010)  
 
automatic zero-tracking (AZT) mechanism. –  See “automatic zero -tracking (AZT) mechanism.” (NOTE:  
AZT maintains zero with specified limits.  “Zero -setting sets/establishes zero with limits based on scale 
capacity.) [2.20, 2.22, 2.24]  
 
initial zero -setting mechanism.  – Automatic means provided to set the indication to zero at the time the 
instrument is switched on and before it is ready for use. [2.20]  
(Added 1990)  
 
manual zero -setting mechanism.  – Nonautomatic means provided to attain a zero balance indication by the 
direct operation of a control. [2.20]  
 
semiautomatic zero -setting mechanism.  – Automatic means provided to attain a direct zero balance 
indication requiring a single initiation by an o perator. [2.20]  
(Amended 2010)  
 
zero-setting mechanism (belt -conveyor scale).  – A mechanism enabling zero totalization to be obtained over a 
whole number of belt revolutions. [2.21, 2.23]  
(Added 2002)  
 
zero-tracking mechanism . – See “automatic zero -tracking mechanism” under “zero -setting mechanism.” [2.20, 
2.22, 2.24]  
 zone of uncertainty.  – The zone between adjacent increments on a digital device in which the value of either of the 
adjacent increments may be displayed. [2.20]  
  
 
 
 
  
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 1.10.  General Code   Handbook 44 –  20152016  
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Section 1.10.  General Code  
 
 
G-A. Application  
 
G-A.1. Commercial and Law -Enforcement Equipment.  – These specifications, tolerances, and other technical 
requirements apply as follows:  
 
(a) To commercial weighing and measuring equipment; that is, to weights and measures and weighing and 
measuring devices commercially used or employed in establishing the size, quantity, extent, area, 
composition (limited to meat and poultry), constituent values (limited to grain), or measurement of 
quantities, things, produce, or articles for distribution or consumption, purchased, offered, or submitted for 
sale, hire, or award, or in computing any basic charge or payment for services rendered on the basis of 
weight or measure.  
(Amended 2008)  
 (b) To any accessory attached to or us ed in connection with a commercial weighing or measuring device when 
such accessory is so designed that its operation affects the accuracy of the device.  
 (c) To weighing and measuring equipment in official use for the enforcement of law or for the collection of 
statistical information by government agencies.  
 
(These requirements should be used as a guide by the weights and measures official when, upon request, courtesy 
examinations of noncommercial equipment are made.)  
 
G-A.2. Code Application.  – This General Code shall apply to all classes of devices as covered in the specific 
codes.  The specific code requirements supersede General Code requirements in all cases of conflict.  
(Amended 1972)  
 
G-A.3. Special and Unclassified Equipment.  – Insofar as th ey are clearly appropriate, the requirements and 
provisions of the General Code and of specific codes apply to equipment failing, by reason of special design or otherwise, to fall clearly within one of the particular equipment classes for which separate co des have been 
established.  With respect to such equipment, code requirements and provisions shall be applied with due regard to the design, intended purpose, and conditions of use of the equipment.  
 
G-A.4. Metric Equipment.  – Employment of the weights and  measures of the metric system is lawful throughout 
the United States.  These specifications, tolerances, and other requirements shall not be understood or construed as in any way prohibiting the manufacture, sale, or use of equipment designed to give resu lts in terms of metric units.  
The specific provisions of these requirements and the principles upon which the requirements are based shall be 
applied to metric equipment insofar as appropriate and practicable.  The tolerances on metric equipment, when not  
specified herein, shall be equivalent to those specified for similar equipment constructed or graduated in the U.S. customary system.  
 
G-A.5. Retroactive Requirements.  – “Retroactive” requirements are enforceable with respect to all equipment.  
Retroactiv e requirements are printed herein in upright roman type.  
 
G-A.6. Nonretroactive Requirements.  – “Nonretroactive” requirements are enforceable on or after the effective 
date for devices:  
 
(a) manufactured within a state after the effective date;  
 (b) both new and used, brought into a state after the effective date;  Handbook 44 –  20152016   1.10.  General Code  
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(c) used in noncommercial applications which are placed into commercial use after the effective date; and  
 (d) undergoing type evaluation, including devices that have been modified to the extent that a new NTEP 
Certificate of Conformance (CC) is required.  
 
Nonretroactive requirements are not enforceable with respect to devices that are in commercial service in the state as 
of the effective date or to new equipment in the stock of a manufact urer or a dealer in the state as of the effective 
date.  
[Nonretroactive requirements are printed in italic type.]  
(Amended 1989 and 2011)  
 
G-A.7. Effective Enforcement Dates of Code Requirements.  – Unless otherwise specified, each new or amended 
code requi rement shall not be subject to enforcement prior to January  1 of the year following the adoption by the 
National Conference on Weights and Measures and publication by the National Institute of Standards and 
Technology.  
 
G-S. Specifications  
 
G-S.1. Identification.  – All equipment, except weights and separate parts necessary to the measurement process 
but not having any metrological effect, shall be clearly and permanently marked for the purposes of identification 
with the following information:  
 
(a) the name, initials, or trademark of the manufacturer or distributor;  
 
(b) a model identifier that positively identifies the pattern or design of the device;  
 
(1) The model identifier shall be prefaced by the word “Model,” “Type,” or “Pattern.”  These terms  may 
be followed by the word “Number” or an abbreviation of that word.  The abbreviation for the word 
“Number” shall, as a minimum, begin with the letter “N” (e.g., No or No.).  The abbreviation for the 
word “Model” shall be “Mod” or “Mod.”  Prefix letteri ng may be initial capitals, all capitals, or all 
lower case.  
[Nonretroactive as of January  1, 2003]  
(Added 2000) (Amended 2001)  
 
(c) a nonrepetitive serial number, except for equipment with no moving or electronic component parts and not -
built- for-purpose,  software -based devices;  
[Nonretroactive as of January  1, 1968]  
(Amended 2003)  
 
(1) The serial number shall be prefaced by words, an abbreviation, or a symbol, that clearly identifies the 
number as the required serial number.  
[Nonretroactive as of January  1, 1986]  
 
(2) Abbreviations for the word “Serial” shall, as a minimum, begin with the letter “S,” and abbreviations 
for the word “Number” shall, as a minimum, begin with the letter “N” (e.g., S/N, SN, Ser.  No., and 
S. No.).  
[Nonretroactive as of Januar y 1, 2001]  
 
(d) the current software version or revision identifier for not -built- for-purpose, software -based devices;  
[Nonretroactive as of January  1, 2004]  
(Added 2003)  
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 (1) The version or revision identifier shall be prefaced by words, an abbreviation, or a symbol, that 
clearly identifies the number as the required version or revision.  
[Nonretroactive as of January  1, 2007]  
(Added 2006)  
 
(2) Abbreviations for the word “Version” shall, as a minimum, begin with the letter “V” and may be 
followed by the word “Numbe r.”  Abbreviations for the word “Revision” shall, as a minimum, begin 
with the letter “R” and may be followed by the word “Number.”  The abbreviation for the word “Number” shall, as a minimum, begin with the letter “N” (e.g., No or No.).  
 [Nonretroactive as of January  1, 2007]  
(Added 2006)  
 (e) an National Type Evaluation Program (NTEP) Certificate of Conformance (CC) number or a 
corresponding CC Addendum Number for devices that have a CC.  The CC Number or a corresponding CC 
Addendum Number shall be prefaced by the terms “NTEP CC,” “CC,” or “Approval.”  These terms may be followed by the word “Number” or an abbreviation of that word.  The abbreviation for the word 
“Number” shall, as a minimum, begin with the letter “N” (e.g.,  No or No.).  
[Nonretroacti ve as of January  1, 2003]  
 
The required information shall be so located that it is readily observable without the necessity of the disassembly of 
a part requiring the use of any means separate from the device.  
(Amended 1985, 1991, 1999, 2000, 2001, 2003, a nd 2006)  
 
G-S.1.1.  Location of Marking Information for Not -Built- For- Purpose, Software -Based Devices.  – For not -
built- for-purpose, software -based devices either:  
 
(a) The required information in G -S.1 Identification. (a), (b), (d), and (e) shall be permanently marked or 
continuously displayed on the device; or  
 
(b) The Certificate of Conformance (CC) Number shall be:  
 
(1) permanently marked on the device;  
 
(2) continuously displayed; or  
 
(3) accessible through an easily recognized menu and, if necessary, a submenu.  Examples of menu 
and submenu identification include, but are not limited to, “Help,” “System Identification,” 
“G-S.1. Identification,” or “Weights and Measures Identification.”  
 
Note:   For (b), clear instructions for accessing the information required in G -S.1. (a), (b), and (d) shall be listed on the 
CC, including information necessary to identify that the software in the device is the same type that was evaluated.  
[Nonretroactive as of January  1, 2004]  
(Added 2003) (Amended 2006)  
 
G-S.1.2. Devices and Main Elements  Rem anufactured as of January 1, 2002.  – All devices and main 
elements remanufactured as of January  1, 2002, shall be clearly and permanently marked for the purposes of 
identification with the following information:  
 
(a) the name, initials, or trademark of the last remanufacturer or distributor; and  
 
(b) the remanufacturer’s or distributor’s model designation, if different than the original model designation.  
(Added 2001)  (Amended 2011)  
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 Note:   Definitions for “manufactured device,” “repaired device,” and “repaired element” are  included (along with definitions 
for “remanufactured device” and “remanufactured element”) in Appendix  D, Definitions.  
 
G-S.2. Facilitation of Fra ud. – All equipment and all mechanisms, software, and devices attached to or used in 
conjunction therewith shall be so designed, constructed, assembled, and installed for use such that they do not 
facilitate the perpetration of fraud.  
(Amended 2007)  
 
G-S.3. Permanence.  – All equipment shall be of such materials, design, and construction as to make it probable 
that, under normal service conditions:  
 
(a) accuracy will be maintained;  
 
(b) operating parts will continue to function as intended; and  
 (c) adjustments will remain reasonably permanent.  
 Undue stresses, deflections, or distortions of parts shall not occur to the extent that accuracy or permanence is 
detrimentally affected.  
 
G-S.4. Interchange or Reversal of Parts.  – Parts of a device that may readily be interchanged or reversed in the 
course of field assembly or of normal usage shall be:  
 
(a) so constructed that their interchange or reversal will not affect the performance of the device; or  
 
(b) so marked as to show their proper positions.  
 
G-S.5. Indicating and Recording Elements.  
 
G-S.5.1. General.  – All weighing and measuring devices shall be provided with indicating or recording 
elements appropriate in design and adequate in amount.  Primary indications and recorded representations shall 
be clear, definite, accurate, and easily read under any conditions of normal operation of the device.  
 
G-S.5.2. Graduations, Indications, and Recorded Representations.  
 
G-S.5.2.1.  Analog Indication and Representation.  – Graduations and a suitable indicator  shall be 
provided in connection with indications designed to advance continuously.  
 
G-S.5.2.2.  Digital Indication and Representation.  – Digital elements shall be so designed that:  
 
(a) All digital values of like value in a system agree with one another.  
 
(b) A digital value coincides with its associated analog value to the nearest minimum graduation.  
 
(c) A digital value “rounds off” to the nearest minimum unit that can be indicated or recorded.  
 (d) A digital zero indication includes the display of a zero for all places that are displayed to the right 
of the decimal point and at least one place to the left.  When no decimal values are displayed, a 
zero shall be displayed for each place of the displayed scale division.  
[Nonretroactive as of January  1, 1986]  
(Amended 1973 and 1985)  
 
G-S.5.2.3.  Size and Character.  – In any series of graduations, indications, or recorded 
representations, corresponding graduations and units shall be uniform in size and character.  Graduations, 1.10.  General Code   Handbook 44 –  20152016  
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 indications, or recorded representations that are subordinate to, or of a lesser value than  others with which 
they are associated, shall be appropriately portrayed or designated.  
[Made retroactive as of January  1, 1975]  
 
G-S.5.2.4.  Values.  – If graduations, indications, or recorded representations are intended to have 
specific values, these shal l be adequately defined by a sufficient number of figures, words, symbols, or 
combinations thereof, uniformly placed with reference to the graduations, indications, or recorded 
representations and as close thereto as practicable, but not so positioned as t o interfere with the accuracy of 
reading.  
 
G-S.5.2.5.  Permanence. – Graduations, indications, or recorded representations and their defining 
figures, words, and symbols shall be of such character that they will not tend easily to become obliterated 
or ille gible.  
 
G-S.5.3. Values of Graduated Intervals or Increments.  – In any series of graduations, indications, or 
recorded representations, the values of the graduated intervals or increments shall be uniform throughout the 
series.  
 
G-S.5.3.1.  On Devices That Indicate or Record in More Than One Unit. –  On devices designed 
to indicate or record in more than one unit of measurement, the values indicated and recorded shall be 
identified with an appropriate word, symbol, or abbreviation.  
(Amended 1978 and 1986)  
 
G-S.5.4. Repeatability of Indications.  – A device shall be capable of repeating, within prescribed tolerances, 
its indications and recorded representations.  This requirement shall be met irrespective of repeated manipulation of any element of the device in a manner approximating normal usage (including displacement of 
the indicating elements to the full extent allowed by the construction of the device and repeated operation of a 
locking or relieving mechanism) and of the repeated performance of steps or operations that are embraced in the 
testing procedure.  
 G-S.5.5. Money Values, Mathematical Agreement.  – Any recorded money value and any digital 
money -value indication on a computing- type weighing or measuring device used in retail trade shall be in 
mathematical agreement with its associated qu antity representation or indication to the nearest 1  cent of money 
value.  This does not apply to auxiliary digital indications intended for the operator’s use only, when these 
indications are obtained from existing analog customer indications that meet th is requirement.  
(Amended 1973)  
 G-S.5.6. Recorded Representations.  – Insofar as they are appropriate, the requirements for indicating and 
recording elements shall also apply to recorded representations.  All recorded values shall be printed digitally.  
In applications where recorded representations are required, the customer may be given the option of not 
receiving the recorded representation.  For systems equipped with the capability of issuing an electronic receipt, 
ticket, or other recorded representatio n, the customer may be given the option to receive any required 
information electronically (e.g., via cell phone, computer, etc.) in lieu of or in addition to a hard copy.  
(Amended 1975 and 2014)  
 
G-S.5.6.1.  Indicated and Recorded Representation of Units.  – Appropriate abbreviations.  
 
(a) For equipment manufactured on or after January  1, 2008, the appropriate defining symbols are 
shown in NIST Special Publication  SP 811 “Guide for the Use of International System of Units 
(SI)” and Handbook  44 Appendix  C – Gene ral Tables of Units of Measurement.  
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 Note:   SP 811 can be viewed or downloaded at http://physics.nist.gov/cuu/pdf/sp811.pdf  or by going to 
http://www.nist.gov/pml/wmd/index.cfm  and selecting Weights and Measures Publications and the link to 
Special Publications (SP 811), “Guide for the Use of the International System of Units  (SI).”  
(Added 2007)  
 
(b) The appropriate defining symbols on equipment manufactured prior to January  1, 2008, with 
limited character sets are shown in Table 1. Representation of SI Units on Equipment 
Manufactured Prior to January  1, 2008, with Limited Character Sets.  
(Added 1977) (Amended 2007)  
 
Table 1.  
Representation of SI Units on Equipment Manufactured Prior to January  1, 2008,  
with Limited Character Sets  
  Representation  
  Form I  Form II  
Name of Unit  International 
Symbol (common 
use symbol)  (double case)  (single case lower)  (single case upper)  
Base SI Units  
meter  m m m M 
kilogram  kg kg kg KG 
Derived SI Units  
newton  N N n N 
pascal  Pa Pa pa PA 
watt W W w W 
volt V V v V 
degree Celsius  °C °C °c °C 
Other Units  
liter l or L  L l L 
gram  g g g G 
metric  ton t t tne TNE  
bar bar bar bar BAR  
 (Table Amended 2007)  
 
G-S.5.7. Magnified Graduations and Indications.  – All requirements for graduations and indications apply 
to a series of graduations and an indicator magnified by an optical system or as magnified and projected on a screen.  
 G-S.6. Marking Operational Controls, Indications, and Features.  – All operational controls, indications, and 
features, including switches, lights, displays, push buttons, and other means, shall be clearly and definitely 
identified.  The use of approved pictograms or symbols shall be acceptable.  
[Nonretroactive as of Jan uary 1, 1977]  
(Amended 1978 and 1995)  
 
G-S.7. Lettering.  – All required markings and instructions shall be distinct and easily readable and shall be of 
such character that they will not tend to become obliterated or illegible.  
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 G-S.8. Provision for Sealing  Electronic Adjustable Components.  – A device shall be designed with provision(s) 
for applying a security seal that must be broken, or for using other approved means of providing security (e.g., data 
change audit trail available at the time of inspection),  before any change that detrimentally affects the metrological 
integrity of the device can be made to any electronic mechanism.  
[Nonretroactive as of January  1, 1990]  
 A device may be fitted with an automatic or a semi -automatic calibration mechanism.  This mechanism shall be 
incorporated inside the device.  After sealing, neither the mechanism nor the calibration process shall facilitate fraud.  
(Added 1985) (Amended 1989 and 1993)  
 
G-S.8.1.  Multiple Weighing or Measuring Elements that Share a Common Provis ion for Sealing.  – A 
change to any metrological parameter (calibration or configuration) of any weighing or measuring element 
shall be individually identified.  
[Nonretroactive as of January  1, 2010]  
 
Note:  For devices that utilize an electronic form of sealing, in addition to the requirements in G -S.8.1., any appropriate audit 
trail requirements in an applicable specific device code also apply.  Examples of identification of a change to the metrological parameters of a weighing or m easuring element include, but are not limited to:  
 
(1) a broken, missing, or replaced physical seal on an individual weighing, measuring, or indicating element or active 
junction box;  
 
(2) a change in a calibration factor or configuration setting for each weighing or measuring element ; 
 
(3) a display of the date of calibration or configuration event for each weighing or measuring element; or  
 
(4) counters indicating the number of calibration and/or configuration events for each weighing or measuring element.  
(Added 2007)  
 
G-N. Notes  
 
G-N.1. Conflict of Laws and Regulations.  – If any particular provisions of these specifications, tolerances, and 
other requirements are found to conflict with existing state laws, or with existing regulations or local ordinances relating to health, safety, or fire prevention, the enforcement of such provisions shall be suspended until conflicting 
requirements can be harmonized.  Such suspension shall not affect the validity or enforcement of the remaining provisions of these specifications, tolerances, and other requirements.  
 
G-N.2. Testing With  Nonassociated Equipment.  – Tests to determine conditions, such as radio frequency 
interference (RFI) that may adversely affect the performance of a device shall be conducted with equipment and under conditions that are usual and customary with respect to the location and use of the device.  
(Added 1976)  
 
G-T. Tolerances  
 
G-T.1. Acceptance Tolerances.  – Acceptance tolerances shall apply to equipment:  
 
(a) to be put into commercial use for the first time;  
 (b) that has been placed in commercial service within  the preceding 30  days and is being officially tested for 
the first time;  
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 (c) that has been returned to commercial service following official rejection for failure to conform to 
performance requirements and is being officially tested for the first time within 30  days after corrective 
service;  
 
(d) that is being officially tested for the first time within 30  days after major reconditioning or overhaul; and  
 
(e) undergoing type evaluation.  
(Amended 1989)  
 G-T.2. Maintenance Tolerances.  – Maintenance tolerances shall apply to equipment in actual use, except as 
provided in  G-T.1. Acceptance Tolerances.  
 G-T.3. Application.  – Tolerances “in excess” and tolerances “in deficiency” shall apply to errors in excess and to 
errors in deficiency, respectively.  Tolerances “on overregistration” and tolerances “on underregistration” shall apply to errors in the direction of overregistration and of underregistration, respectively.  (Also see Appendix  D, 
Definitions.)  
 G-T.4. For Intermediate Values.  – For a capacity, indication, load, value, etc., intermediate between two 
capacities, indications, loads, values, etc., listed in a table of tolerances, the tolerances prescribed for the lower 
capacity, indication, load, value, etc., shall be applied.  
G-UR. User Requirements  
 
G-UR.1.  Selection Requirements.  
 
G-UR.1.1.  Suitability of Equipment.  – Commercial equipment shall be suitable for the service in which it is 
used with respect to elements of its design, including but not limited to its weighing capacity  (for weighing 
devices), its computing capability (for computing devices), its rate of flow (for liquid -measuring devices), the 
character, number, size, and location of its indicating or recording elements, and the value of its smallest unit 
and unit price s. 
(Amended 1974)  
 G-UR.1.2.  Environment.  – Equipment shall be suitable for the environment in which it is used including, but 
not limited to, the effects of wind, weather, and RFI.  
(Added 1976)  
 G-UR.1.3.  Liquid -Measuring Devices.  – To be suitable for its application, the minimum delivery for 
liquid -measuring devices shall be no less than 100  divisions, except that the minimum delivery for retail analog 
devices shall be no less than 10  divisions.  Maximum division values and tolera nces are stated in the specific 
codes.  
(Added 1995)  
 
G-UR.2.  Installation Requirements.  
 
G-UR.2.1.  Installation.  – A device shall be installed in accordance with the manufacturer’s instructions, 
including any instructions marked on the device.  A device in stalled in a fixed location shall be installed so that 
neither its operation nor its performance will be adversely affected by any characteristic of the foundation, 
supports, or any other detail of the installation.  
 
G-UR.2.1.1.  Visibility of Identification.  – Equipment shall be installed in such a manner that all 
required markings are readily observable.  
(Added 1978)  
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 G-UR.2.2.  Installation of Indicating or Recording Element.  – A device shall be so installed that there is no 
obstruction betwee n a primary indicating or recording element and the weighing or measuring element; 
otherwise there shall be convenient and permanently installed means for direct communication, oral or visual, 
between an individual located at a primary indicating or record ing element and an individual located at the 
weighing or measuring element.  (Also see G -UR.3.3. Position of Equipment.)  
 G-UR.2.3.  Accessibility for Inspection, Testing, and Sealing Purposes.  – A device shall be located, or such 
facilities for normal access thereto shall be provided, to permit:  
 
(a) inspecting and testing the device;  
 
(b) inspecting and applying security seals to the device; and  
 (c) readily bringing the testing equipment of the weights and measures official to the device by customary 
means and in the amount and size deemed necessary by such official for the proper conduct of the test.  
 
Otherwise, it shall be the responsibility of the device owner or operator to supply such special facilities, 
including such labor as may be needed to in spect, test, and seal the device, and to transport the testing 
equipment to and from the device, as required by the weights and measures official.  
(Amended 1991)  
 
G-UR.3.  Use Requirements.  
 
G-UR.3.1.  Method of Operation.  – Equipment shall be operated only in the manner that is obviously 
indicated by its construction or that is indicated by instructions on the equipment.  
 
G-UR.3.2.  Associated and Nonassociated Equipment.  – A device shall meet all performance requirements 
when associated or nonassociated equipment is operated in its usual and customary manner and location.  
(Added 1976)  
 
G-UR.3.3.  Position of Equipment.  – A device or system equipped with a primary indicating element and 
used in direct sales, except for prescr iption scales, shall be positioned so that its indications may be accurately 
read and the weighing or measuring operation may be observed from some reasonable “customer” and 
“operator” position.  The permissible distance between the equipment and a reasonable customer and operator 
position shall be determined in each case upon the basis of the individual circumstances, particularly the size and character of the indicating element.  
(Amended 1974 and 1998)  
 G-UR.3.4.  Responsibility, Money -Operated Devices.  – Money- operated devices, other than parking meters, 
shall have clearly and conspicuously displayed thereon, or immediately adjacent thereto, adequate information 
detailing the method for the return of monies paid when the product or service cannot be obtain ed.  This 
information shall include the name, address, and phone number of the local responsible party for the device.  This requirement does not apply to devices at locations where employees are present and responsible for 
resolving any monetary discrepan cies for the customer.  
(Amended 1977 and 1993)  
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 G-UR.4.  Maintenance Requirements.  
 
G-UR.4.1.  Maintenance of Equipment.  – All equipment in service and all mechanisms and devices attached 
thereto or used in connection therewith shall be continuously maintained in proper operating condition 
throughout the period of such service.  Equipment in service at a single place of bus iness found to be in error 
predominantly in a direction favorable to the device user (also see the Introduction, Section  Q) shall not be 
considered “maintained in a proper operating condition .”” if: 
 
(a) predominantly, equipment of all types or applications are found to be in error in a direction favorable 
to the device user; or  
 
(b) predominantly, equipment of the same type or application is found to be in error in a direction 
favorable to the device user.  
(Amended 1973, 1991,  and 19912015)  
 G-UR.4.2.  Abnormal P erformance.  – Unstable indications or other abnormal equipment performance 
observed during operation shall be corrected and, if necessary, brought to the attention of competent service personnel.  
(Added 1976)  
 G-UR.4.3.  Use of Adjustments.  – Weighing eleme nts and measuring elements that are adjustable shall be 
adjusted only to correct those conditions that such elements are designed to control, and shall not be adjusted to 
compensate for defective or abnormal installation or accessories or for badly worn or  otherwise defective parts 
of the assembly.  Any faulty installation conditions shall be corrected, and any defective parts shall be renewed 
or suitably repaired, before adjustments are undertaken.  Whenever equipment is adjusted, the adjustments shall 
be so made as to bring performance errors as close as practicable to zero value.  
 
G-UR.4.4.  Assistance in Testing Operations.  – If the design, construction, or location of any device is such 
as to require a testing procedure involving special equipment or accessories or an abnormal amount of labor, such equipment, accessories, and labor shall be supplied by the owner or operator of the device as required by 
the weights and measures official.  
 
G-UR.4.5.  Security Seal.  – A security seal shall be appropriately affixed to any adjustment mechanism 
designed to be sealed.  
 
G-UR.4.6.  Testing Devices at a Central Location.  
 
(a) When devices in commercial service require special test facilities, or must be removed from service for 
testing, or are routinely transported for the purpose of use (e.g., vehicle -mounted devices and devices 
used in multiple locations), the official with statutory authority may require that the devices be brought 
to a central location for testing.  The d ealer or owner of these devices shall provide transportation of 
the devices to and from the test location.  
 
(b) When the request for removal and delivery to a central test location involves devices used in submetering (e.g., electric, hydrocarbon vapor, or  water meters), the owner or operator shall not 
interrupt the utility service to the customer or tenant except for the removal and replacement of the device.  Provisions shall be made by the owner or operator to minimize inconvenience to the customer 
or te nant.  All replacement or temporary meters shall be tested and sealed by a weights and measures 
official or bear a current, valid approval seal prior to use.  
(Added 1994)  
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Section 2.20.  Scales  
 
 
A. Application  
 
A.1. General.  – This code applies to all types of weighing devices other than automatic bulk -weighing systems, 
belt-conveyor scales , and automatic weighing systems.  The code  comprises requirements that generally apply to all 
weighing devices, and specific requirements that are applicable only to certain types of weighing devices.  
(Amended 1972 and 1983)  
 
A.2. Wheel -Load Weighers, Portable Axle -Load Weighers, and Axle -Load Sca les. – The requirements for 
wheel -load weighers,  portable axle -load weighers,  and axle- load scales  apply only to such scales in official use for 
the enforcement of traffic and highway laws or for the collection of statistical information by government agencies.  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, devices covered by the 
Scales code shall meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Zero Indication.  
 
(a) On a scale equipped with indicating or recording elements , provision shall be made to either indicate 
or record a zero -balance condition . 
 
(b) On an automatic -indicating scale or balance indicator , provision shall be made to indicate or record an 
out-of-balance condition  on both sides of zero.  
 
(c) A zero-balance condition  may be indicated by other than a continuous digital zero indication , provided 
that an effective automatic means is provided to inhibit a weighing operation or to return to a 
continuous digi tal indication when the scale is in an out -of-balance condition.  
(Added 1987) (Amended 1993)  
(Amended 1987)  
 
S.1.1.1.  Digital Indicating Elements.  
 
(a) A digital zero indication  shall represent a balance condition  that is within ±  ½ the value of the 
scale division.  
 
(b) A digital indicating device shall either automatically maintain a “center -of-zero” condition to 
± ¼ scale  division or less, or have an auxiliary or supplemental “center -of-zero” indicator  that 
defines a zero -balance condition to ± ¼ of a scale division or less.   A “center -of-zero” indication 
may operate when zero is indic ated for gross and/or net mode(s).  
[Nonretroactive as of January  1, 1993]  
(Amended 1992 and 2008)  
 
S.1.1.2.  No-Load Reference Value.  – On a single draft manually operated receiving hopper scale 
installed below grade, used to receive grain, and utilizing a no -load reference value,  provision shall be 
made to indicate and record the no -load reference value pri or to the gross load value.  
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S.1.2.  Value of Scale Division Units.  – Except for batching scales and weighing systems used 
exclusively for weighing in predetermined amounts, the value of a scale division “d” expressed in a unit of 
weight shall be equal to:  
 
(a) 1, 2, or 5; or  
  
(b) a decimal multiple or submultiple of 1, 2, or 5; or  
 
 Examples:  scale divisions may be 10, 20, 50, 100; or 0.01, 0.02, 0.05; or 0.1, 0.2, 0.5, etc.  
 
(c) a binary submultiple of a specific unit of weight.  
 
 Examples:  scale divisions may be ½, ¼, 1/8, 1/16, etc.  
[Nonretroactive as of January  1, 1986]  
 S.1.2.1.  Digital Indicating Scales, Units.  – Except for postal  scales, a digital- indicating scale shall 
indicate weight values using only a single unit of measure.  Weight values shall be presented in a decimal format with the value  of the scale division expressed as 1,  2, or  5, or a decimal multiple or submultiple o f 
1, 2, or  5. 
 
The requirement that the value of the scale division be expressed only as 1,  2, or  5, or a decimal multiple or 
submultiple of only 1,  2, or  5 does not apply to net weight indications and recorded representations that 
are calculated from gros s and tare weight indications where the scale division of the gross weight is 
different from the scale division of the tare weight(s) on multi- interval or multiple range scales.  For 
example, a multiple range or multi -interval scale may indicate and record tare weights in a lower weighing 
range (WR) or weighing segment (WS), gross weights in the higher weighing range or weighing segment, 
and net weights as follows:  
 
55 kg Gross Weight (WR2  d = 5  kg) 10.05  lb Gross Weight (WS2  d = 0.05  lb) 
– 4 kg Tare Weight   (WR1  d = 2  kg) – 0.06 lb Tare Weight   (WS1  d = 0.02  lb) 
= 51  kg Net Weight     (Mathematically Correct)  = 9.99  lb Net Weight     (Mathematically Correct)  
[Nonretroactive as of January  1, 1989]  
(Added 1987) (Amended 2008)  
 
S.1.2.2.  Verification Scale Interval.  
 
S.1.2.2.1.  Class I and  II Scales and Dynamic Monorail Scales.  If e  ≠ d, the verification scale 
interval  “e” shall be determined by the expression:  
 
d < e <  10 d 
 
If the displayed division  (d) is less than the verification division  (e), then the verification division shall 
be less than or equal to 10 times the displayed division.  
 The value of e must satisfy  the relationship, e  = 10
k of the unit of measure, where k is a positive or 
negative whole number or zero.  This requirement does not apply to a Class  I device with d  < 1 mg 
where e = 1 mg.  If e  ≠ d, the value of “d” shall be a decimal submultiple of “e,” and the ratio shall not 
be more than 10:1.  If e  ≠ d, and both “e” and “d” are continuously displayed during normal operation, 
then “d” shall be differentiated from “e” by size, shape, color, etc. throughout the range of weights 
displayed as “d.”  
(Added 1999)  
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 S.1.2.2.2.  Class III and  IIII Scales.   The value of “e” is specified by the manufacturer as marked 
on the device.  Except for dynamic monorail scales , “e” must be less than or equal to “d.”  
(Added 1999)  
 
S.1.2.3.  Prescription Scale with a Counting Feature.  – A Class I or Class II prescription scale with an 
operational counting feature shall not calculate a piece weight or total count unless the sample used to 
determine the individual piece weight meets the following conditions:  
 
(a) minimum individual piece weight is greater than or equal to 3  e; and  
 
(b) minimum sample piece count is greater than or equal to 10  pieces.  
(Added 2003)  
 
 S.1.3.  Graduations.  
 
S.1.3.1.  Length.  – Graduations  shall be so varied in length that they may be conveniently read.  
 
S.1.3.2.  Width.  – In any series of graduations,  the width of a graduation shall in no case be greater than 
the width of the clear space between graduations.  The width of main graduations shall be not more than 
50 % greater than the width of subordinate graduations.  Graduations shall be not less than 0.2  mm 
(0.008 in) wide.  
 S.1.3.3.  Clear Space Between Graduations.  – The clear space between graduations  shall be not less 
than 0.5 mm (0.02  in) for graduations representing money- values, and not less than 0.75  mm (0.03  in) for 
other graduations.  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations  at the end of the indicator ; or 
 
(b) if the indicator  is continuous, at the point of widest separation of the graduations . 
 
 S.1.4.  Indicators.  
 
S.1.4.1.  Symmetry.  – The index of an indicator  shall be of the same shape as the graduations , at least 
throughout that portion of its length associated with the graduations.  
 
S.1.4.2.  Length.  – The index of an indicator  shall reach to the finest graduations  with which it is used, 
unless the indicator  and the graduations are in the same plane, in which case, the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations,  shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.4.3.  Width.  – The width of the index of an indicator  in relation to the series of graduations  with 
which it is used shall be not greater than:  
 
(a) the width of the narrowest graduation;  
[Nonretroactive as of January  1, 2002]  
 
(b) the width of the clear space between weight graduations ; and  
 
(c) three -fourths of the width of the clear space between money -value graduations . 
 
When the index of an indicator  extends along the entire length of a graduation, that portion of the index of 
the indicator  that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
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 S.1.4.4.  Clearance.  – The clearance between the index of an indicator  and the graduations  shall in no 
case be mo re than 1.5  mm (0.06  in). 
 
S.1.4.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
 S.1.5.  Weighbeams.  
 
S.1.5.1.  Normal Balance Position.  – The normal balance position  of the weighbeam of a beam scale 
shall be horizontal.  
 
S.1.5.2.  Travel.  – The weighbeam of a beam scale shall have equal travel  above and below the 
horizontal.  The total travel of the weighbeam of a beam scale in a trig loop or between other limiting stops 
near the weighbeam tip shall be not less than the minimum travel shown in Tables  1M and  1.  When such 
limiting stops are not provided, the total travel at the weighbeam tip shall be not less than 8  % of the 
distance from the weighbeam fulcru m to the weighbeam tip.  
 
Table 1M.  
Minimum Travel  of Weighbeam of Beam Scale  
Between Limiting Stops   Table 1.  
Minimum Travel of Weighbeam of Beam Scale  
Between Limiting Stops  
Distance From 
Weighbeam Fulcrum to 
Limiting Stops  
(centimeters)  Minimum Travel 
Between  
Limiting Stops  
(millimeter)   Distance From 
Weighbeam Fulcrum to 
Limiting Stops  
(inches)  Minimum Travel 
Between  
Limiting Stops  
(inch)  
30 or less  10  12 or less  0.4 
30+ to 50, inclusive  13  12+ to 20, inclusive  0.5 
50+ to 100, inclusive  18  20+ to 40, inclusive  0.7 
Over 100  23  Over 40  0.9 
 
S.1.5.3.  Subdivision.  – A subdivided weighbeam bar shall be subdivided by scale division graduations,  
notches, or a combination of both.  Graduations on a particular bar shall be of uniform width and perpendicular to the top edge of the bar.  Notches on a particular bar shall be uniform in shape and 
dimensions and perpendicular to the face of the bar.  Wh en a combination of graduations and notches is 
employed, the graduations shall be positioned in relation to the notches to indicate notch values clearly and 
accurately.  
 
S.1.5.4.  Readability.  – A subdivided weighbeam bar shall be so subdiv ided and marked, and a 
weighbeam poise  shall be so constructed, that the weight corresponding to any normal poise position can 
easily and accurately be read directly from the beam, whether or not provision is made for the optional recording of r epresentations of weight.  
 
S.1.5.5.  Capacity.  – On an automatic -indicating scale having a nominal capacity  of 15 kg (30  lb) or less 
and used for direct sales  to retail customers:  
 
(a) the capacity  of any weighbeam bar shall be a multiple of the reading -face capacity;  
 
(b) each bar shall be subdivided throughout or shall be subdivided into notched intervals, each equal 
to the reading -face capacity ; and  
 
(c) the value of a ny turnover poise  shall be equal to the reading -face capacity . 
 
S.1.5.6.  Poise Stop.  – Except on a steelyard with no zero graduation, a shoulder or stop shall be 
provided on each weighbeam bar to prevent a poise  from tra veling and remaining back of the zero 
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S.1.6.  Poises.  
 
S.1.6.1.  General.  – No part of a poise  shall be readily detachable.  A locking screw shall be 
perpendicular to the longitudinal axis of the weighbeam and shall not be removable.  Except on a steelyard 
with no zero graduation, the poise shall not be readily removable from a weighbeam.  The knif e-edge of a 
hanging poise shall be hard and sharp and so constructed as to allow the poise to swing freely on the bearing surfaces in the weighbeam notches.  
 
S.1.6.2.  Adjusting Material.  – The adjusting material in a poise  shall be securely enclosed and firmly 
fixed in position; if softer than brass, it shall not be in contact with the weighbeam.  
 
S.1.6.3.  Pawl.  – A poise,  other than a hanging poise, on a notched weighbeam bar shall have a pawl that 
will seat the  poise in a definite and correct position in any notch, wherever in the notch the pawl is placed, 
and hold it there firmly and without appreciable movement.  The dimension of the tip of the pawl that is 
transverse to the longitudinal axis of the weighbeam shall be at least equal to the corresponding dimension 
of the notches.  
 
S.1.6.4.  Reading Edge or Indicator.  – The reading edge or indicator  of a poise  shall be sharply defined, 
and a reading edge shall be parallel to the graduatio ns on the weighbeam.  
 
S.1.7.  Capacity Indication, Weight Ranges, and Unit Weights . 
 
(a) Gross Capacity.  – An indicating or recording element shall not display nor record any values when 
the gross load (not counting the initial dead load that has been canceled by an initial zero -setting 
mechanism ) is in excess of 105 % of scale capacity . 
 
(b) Capacity Indication . – Electronic computing scales (excluding postal  scales and weight classifiers)  
shall neither display nor record a gross or net weight  in excess of scale capacity plus 9 d. 
[Nonretroactive as of January  1, 1993]  
 
The total value of weight ranges  and of unit weights  in effect or in place at any time shall automatically be 
accounted for on  the reading face and on any recorded representation.  
 
This requirement does not apply to:   (1) single -revolution dial scales, (2)  multi -revolution dial scales not 
equipped with unit weights , (3) scales equipped with two or more weighbeam s, nor (4) devices that indicate 
mathematically derived totalized values.  
(Amended 1990, 1992, and 1995)  
 
S.1.8.  Computing Scales.  
 
S.1.8.1.  Money -Value Graduations, Metric Unit Prices.  – The value of the graduated intervals 
representing money- values on a computing scale with analog indications shall not exceed:  
 
(a) 1 cent at all unit prices of 55  cents per kilogram and less;  
 
(b) 2 cents at unit prices of 56  cents per kilogram through $2.75 per kilogram (special graduations  
defining 5 -cent intervals may be employed but not in the spaces between regular graduations);  
 
(c) 5 cents at unit prices of $2.76 per kilogram through $7.50 per kilogram; or  
 
(d) 10 cents at unit pr ices above $7.50 per kilogram.  
 
Value figures and graduations  shall not be duplicated in any column or row on the graduated chart.  (Also 
see S.1.8.2. Money -Value Computation.)  
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 S.1.8.2.  Money -Value  Graduations,  U.S. Customary  Unit Prices.  – The value of  the graduated 
intervals representing money- values on a computing scale with analog indications shall not exceed:  
 
(a) 1 cent at all unit prices  of 25 cents per pound and less;  
 (b) 2 cents at unit prices  of 26 cents per pound through $1.25 per pound (special graduations  defining 
5-cent intervals may be employed but not in the spaces between regular graduations);  
 
(c) 5 cents at unit prices  of  $1.26  per pound through $3.40 per pound; or  
 
(d) 10 cents at unit prices  above $3.40 per pound.  
 
Value figures and graduations  shall not be duplicated in any column or row on the graduated chart.  (Also 
see S.1.8.2. Money -Value Computation.)  
 
S.1.8.3.  Money -Value Computation.  – A computing scale with analog quantity indications used in 
retail trade may compute and present digital money -values to the nearest quantity graduation when the 
value of the minimum graduated interval is 0.005  kg (0.01  lb) or less.  (Also see Sec.  1.10.  General Code 
G-S.5.5. Money -Values, Mathematical Agreement.)  
 S.1.8.4.  Customer’s Indications.  – Weight indications shall be shown on the customer’s side of 
computing scales when these are used for direct sales  to retail customers.  Com puting scales  equipped on 
the operator’s side with digital indications, such as the net weight, unit price, or total price, shall be similarly equipped on the customer’s side.  Unit price displays visible to the customer shall be in t erms of 
single whole units of weight and not in common or decimal fractions of the unit.  Scales indicating in 
metric units may indicate price per 100  g. 
(Amended 1985 and 1995)  
 
S.1.8.4.1.  Scales that will function as either a normal round off scale or as  a weight classifier  shall 
be provided with a sealable means for selecting the mode of operation and shall have a clear indication (annunciator), adjacent to the weight display on both the operator’s and customer’s side whenever the scale is operating as a weight classifier . 
[Nonretroactive as of January  1, 2001]  
(Added 1999)  
 
S.1.8.5.  Recorded Representations, Point -of-Sale Systems.  – The sales information recorded by cash 
registers when interfaced with a weighing element shall contain the following information for items weighed at the checkout stand:  
 
(a) the net weight;
27 
 
(b) the unit price;1 
 
                                                           
27 For devices interfaced with scales indicating in metric units, the unit price may be expressed in price per 
100 grams.  Weight values shall be identified by kilograms, kg, grams, g, ounces, oz, pounds, or lb.  The “#” symbol 
is not acceptable.  
[Nonretroactive as of January  1, 2006]  
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 (c) the total price; and  
 
(d) the product class or, in a system equipped with price look -up capability, the product name or code 
number.  
 
S.1.9.  Prepackaging Scales.  
 
S.1.9.1.  Value of the Scale Division.  – On a prepackaging scale, the value of the intervals representing 
weight values shall be uniform throughout the entire reading face.  The recorded weight values shall be 
identical with those on the indicator . 
 
S.1.9.2.  Label Printer.  – A prepackaging scale or a device that produces a printed ticket to be used as 
the label for a package shall print all values digitally and of such size, style of type, and color as to be clear 
and conspicuous on the label.  
 
S.1.10.  Adjustable Components.  – An adjustable component such as a pendulum, spring, or 
potentiometer shall be held securely in adjustment  and, except for a zero -load balance  mechanism, shall be 
located within the housing of the ele ment.  
(Added 1986)  
 
S.1.11.  Provision  for Sealing.  
 
(a) Except on Class  I scales, provision shall be made for applying a security seal  in a manner that 
requires the security seal to be broken before an adjustment  can be made to any component affecting 
the performance of an electronic device.  
[Nonretroactive as of January  1, 1979]  
 
(b) Except on Class  I scales, a device shall be designed with provision(s) for applying a security seal  that 
must be broken, or for using other approved means of providing security (e.g., data change audit trail  
available at the time of inspection), before any change that detrimentally affects the metrological integrity of the device can be made to any electronic mechanism.  
[Nonretroactive as of January  1, 1990]  
 
(c) Except on Class  I scales, audit trails  shall use the format set forth in Table  S.1.11. Categories of 
Device and Methods of Sealing.  
[Nonretroactive as of January  1, 1995]  
 
A device may be fitted with an automatic or a semi -automatic calibration mechanism.  This mechanism shall be 
incor porated inside the device.  After sealing , neither the mechanism nor the calibration process shall facilitate 
fraud.  
(Amended 1989, 1991, and 1993)  
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S.1.12.  Manual Weight Entries.  – A device when being used for direct sale shall accept an entry of a 
manual gross or net weight value only when the scale gross or net* weight indication is at zero.  Recorded manual weight entries, except those on labels generated for packages of standard weights, shall identify the 
weight value as a manual weight entry by one of the following terms:  “Manual Weight,” “Manual Wt,” or “MAN WT.”  The use of a symbol to identify multiple manual weight entries on a single document is permitted, 
provided that t he symbol is defined on the same page on which the manual weight entries appear and the 
definition of the symbol is automatically printed by the recording element as part of the document.  
[Nonretroactive as of January  1, 1993] [*Nonretroactive as of Januar y 1, 2005]  
(Added 1992) (Amended 2004)  
 
S.1.13.  Vehicle On -Board Weighing Systems:  Vehicle in Motion.  – When the vehicle is in motion, a 
vehicle on -board weighing system  shall either:  
 
(a) be accurate; or  
 
(b) inhibit the weighing operation.  
(Added 1993)  
 
S.2. Design of Balance, Tare, Level, Damping, and Arresting Mechanisms.  
 
S.2.1.  Zero -Load Adjustment.  
 
S.2.1.1.  General.  – A scale shall be equipped with means by which the zero -load balance may be 
adjusted.  Any loose material used for this purpose shall be enclosed so that it cannot shift in position and 
alter the balance condition  of the scale.  
 Table S.1.11. Categories of Device and Methods of Sealing  
Categories of Device  Methods of Sealing  
Category  1:  No remote configuration 
capability.  Seal by physical seal or two event counters:  one for calibration 
parameters and one for configuration parameters.  
Category  2:  Remote configuration capability, 
but access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in 
the remote configuration mode and record 
such message if capable of printing in this 
mode.  The hardware enabling access for remote communication must be 
at the device and sealed using a physical seal or two event 
counters:   one for calibration parameters and one for 
configuration parameters.  
Category  3:  Remote configuration capability 
access may be unlimited or controlled through 
a software switch (e.g., password).  An event logger is required in the device; it must include an event 
counter (000 to 999), the parameter ID, the date and time of the 
change, and the new value of the parameter.  A printed copy of the 
information must be available through the device or through 
another on- site device.  The event logger shall have a capacity  to 
retain records equal to 10 times the number of sealable 
parameters in the device, but not more than 1000 records are 
required.   (Note:   Does not require 1000  changes to be stored for 
each pa rameter.)  
[Nonretroactive as of January  1, 1995]  
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 Except for an initial zero -setting mechanism, an automatic zero adjustment outside the limits specified in 
S.2.1.3. Scales Equipped with an Automatic Zero -Tracking Mechanism is prohibited.  
(Amended 2010)  
 
S.2.1.2.  Scales used in Direct  Sales.  – A manual zero -setting mechanism (except on a digital scale with 
an analog zero -adjustment  mechanism with a range of not greater than one scale division) shall be operable 
or accessible only by a tool outside of a nd entirely separate from this mechanism, or it shall be enclosed in 
a cabinet.  Except on Class  I or II scales, a balance ball shall either meet this requirement or not itself be 
rotatable.  
 
A semiautomatic zero -setting mechanism shall be operable or accessible only by a tool outside of and 
separate from this mechanism or it shall be enclosed in a cabinet, or it shall be operable only when the 
indication is stable within plus or minus:  
 
(a) 3.0 scale divisions for scal es of more than 2000 kg (5000 lb) capacity  in service prior to 
January  1, 1981, and for all axle load, railway track, and vehicle scales ; or 
 
(b) 1.0 scale division for all other scales.  
 S.2.1.3.  Scales Equipped with an Automatic Zero -Tracking Mechanism.  
 
S.2.1.3.1.  Automatic Zero -Tracking Mechanism for Scales Manufactured Between 
January 1, 1981, and January 1, 2007.  – The maximum load that can  be “rezeroed,” when either 
placed on or removed from the platform all at once under normal operating conditions, shall be for:  
 
(a) bench, counter, and livestock scales :  0.6  scale division;  
 (b) vehicle, axle load, and railway track  scales:   3.0 scale divisions; and  
 
(c) all other scales:  1.0  scale division.  
 (Amended 2005)  
 
  S.2.1.3.2.  Automatic Zero -Tracking Mechanism for Scales Manufactured on or after 
January 1, 2007.  – The maximum load that can be “rezeroed,” when either placed on or removed from 
the platform all at once under normal operating conditions, shall be:  
 
(a) for vehicle, axle load, and railway track scales :  3.0  scale divisions; and  
 
(b) for all other scales:  0.5  scale division.  
 (Added 2005)  
 
S.2.1.3.3.  Means to Disable Automatic Zero -Tracking Mechanism on Class  III L Devices.  – 
Class  III L devices equipped with an automatic zero- tracking mechanism shall be designed with a 
sealable means that would allow zero tracking to be disabled during the inspection and test of the 
device.  
[Nonretroactive as of January  1, 2001]  
(Added 1999) (Amended 2005)  
 
S.2.1.4.  Monorail Scales.  – On a static monorail scale  equipped with digital indications, means shall be 
provided for setting the zero -load balance to within 0.02 % of scale capacity .  On a dynamic monorail 
weighing system, means shall be provided to automatically maintain these conditions.  
(Amended 1999)  
 
S.2.1.5.  Initial Zero -Setting Mechanism. –  Scales of accuracy  Classes  I, II, and  III may be equipped 
with an initial zero -setting device.  2.20. Scales   Handbook 44 –  20152016  
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 (a) For weighing, load- receiving, and indicating elements in the same housing or covered on the same 
CC, an initial zero -setting mechanism  shall not zer o a load in excess of 20 % of the maximum 
capacity  of the scale unless tests show that the scale meets all applicable tolerances  for any amount 
of initial load compensated by this device within the specified range.  
 (b) For indicating elements not permanently attached to weighing and load -receiving elements 
covered on a separate CC, the maximum initial zero- setting mechanism range of electronic 
indicators shall not exceed 20 % of the configured capacity.  
[Nonretroactive as of  January  1, 2009]  
(Added 2008)  
(Added 1990) (Amended 2008)  
 
S.2.1.6.  Combined Zero -Tare ( “0/T”) Key. –  Scales not intended to be used in direct sales  applications 
may be equipped with a combined zero and tare function key, provi ded that the device is clearly marked as 
to how the key functions.  The device must also be clearly marked on or adjacent to the weight display with 
the statement “Not for Direct Sales.”  
(Added 1998)  
 
S.2.2.  Balance Indicator.  – On a balance indicator  consisting of two indicating edges, lines, or points, 
the ends of the indicators shall be sharply defined.  When the scale is in balance, the ends shall be separated by 
not more than 1.0  mm (0.04 in). 
 
S.2.2.1.  Dairy -Product Test, Grain -Test, Prescription, and Class  I and  II Scales.  – Except on digital 
indicating devices, a dairy -product test , grain -test, prescription , or Class  I or II scale shall be equipped with 
a balance indicator .  If an indicator  and a graduated scale are not in the same plane, the clearance between 
the indicator and the gradua tions  shall be not more than 1.0  mm (0.04 in). 
 
S.2.2.2.  Equal -Arm Scale . – An equal -arm scale shall be equipped with a balance indicator .  If the 
indicator  and balance graduation are not in the same plane, the clearance  between the indicator and the 
balance graduation shall be not more than 1.0 mm (0.04  in). 
[Nonretroactive as of January  1, 1989]  
(Added 1988)  
 
S.2.3.  Tare.  – On any scale (except a monorail scale  equipped with digital indications and multi -interval 
scales or multiple range scales when the value of tare is determined in a lower weighing range or weighing 
segment), the value of the tare  division shall be equal to the value of the scale div ision.*   The tare mechanism 
shall operate only in a backward direction (that is, in a direction of underregistration) with respect to the 
zero-load balance condition  of the scale.   A device designed to automati cally clear any tare value shall also be 
designed to prevent the automatic clearing of tare until a complete transaction has been indicated.*  
[*Nonretroactive as of January  1, 1983]  
(Amended 1985 and 2008)  
 
Note :  On a computing scale, this requires the input of a unit price, the display of the unit price, and a 
computed positive total price at a readable equilibrium.  Other devices require a complete weighing operation, 
including tare , net, and gross weight determination*  
[*Nonretroactive as of  January  1, 1983]  
 
S.2.3.1.  Monorail Scales Equipped with Digital Indications.  – On a static monorail weighing system 
equipped with digital indications, means shall be provided for setting any tare  value of less than 5  % of t he 
scale capacity  to within 0.02  % of scale capacity.  On a dynamic monorail weighing system, means shall be 
provided to automatically maintain this condition.  
(Amended 1999)  
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 S.2.4.  Level -Indicating Means.  – Except for portable wheel -load we ighers  and portable axle load 
scales , a portable scale shall be equipped with level -indicating means  if its weighing performance is changed by 
an amount greater than the appropriate acceptance tolerance when it is tilted up to and including 5  % rise over 
run in any direction from a level position and rebalanced.  The level -indicating means shall be readable without 
removing any scale parts requiring a tool.  
[This requirement is nonretroactive as of January  1, 1986, for prescription, jewelers’ , and dairy -product test  
scales and scales marked Class  I and II.] 
 
Note:   Portable wheel -load weighers  and portable axle- load scales  shall be accurate when tilted up to and including 5 % 
rise over run in any direction from a level position and rebalanced.  
(Amended 1991 and 2008)  
 
S.2.4.1.  Vehicle On -Board Weighing Systems.  – A vehicle on -board weighing system  shall operate 
within tolerance when the weighing system is tilted up to and including 5  % rise over run in any direction 
from a level position and rebalanced.  If the accuracy  of the system is affected by out -of-level conditions  
normal to the use of the device, the system shall be equipped with an out -of-level sensor that inhibits the 
weighing operation when the system is out of level to the extent that the accuracy limits are exceeded.  
(Added 1992) (Amended 2008)  
 
S.2.5.  Damping Means.  – An automatic -indicating scale and a balance indicator  shall be equipped with 
effective means to damp oscillations and to bring the indicating elements  quickly to rest.  
 
S.2.5.1.  Digital Indicating Elements.  – Digital indicating elements  equipped with recording elements  
shall be equipped with effective means to permit the recording of weight values only when the indication is 
stable within plus or minus:  
 
(a) 3.0 scale divisions for scales of more than 2000 kg (5000 lb) capacity  in service prior to 
January  1, 1981, hopper (other than grain hopper) scales with a capacity exceeding 22 000 kg 
(50 000 lb), and for all vehicle, axle load, livestock, and railway track scales ; and  
 
(b) 1.0 scale division for all other scales.  
 
The values recorded shall be within applicable tolerances . 
(Amended 1995)  
 
S.2.5.2.  Jewelers’, Prescription, and Class  I, and Class  II Scales.  – A jewelers’, prescription , Class  I, 
or Class II scales shall be equipped with appropriate means for arresting the oscillation of the mechanism.  
 
S.2.5.3.  Class  I and Class II Prescription Scales with a Counting Feature.  – A Class  I or Class  II 
prescription scale shall indicate to the operator when the piece weight computation is complete by a stable 
display of the quantity placed on the load- receiving element.  
(Add ed 2003)  
 
S.3. Design of Load -Receiving Elements.  
 
S.3.1.  Travel of Pans of Equal -Arm Scale.  – The travel  between limiting stops of the pans of a 
nonautomatic -indicating equal -arm scale not equipped with a balance indicator  shall be not less than the 
minimum travel shown in Table  2M. and Table 2. 
 2.20. Scales   Handbook 44 –  20152016  
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 Table 2M.  
Minimum Travel  of Pans of  
Nonautomatic Indicating Equal -Arm Scale  
Without without  Balance Indicator   Table 2.  
Minimum Travel of Pans of  
Nonautomatic Indicating Equal -Arm Scale  
Without without  Balance Indicator  
Nominal Capacity  
(kilograms)  Minimum Travel of Pans  
(millimeters)   Nominal Capacity  
(pounds)  Minimum Travel of Pans  
(inch)  
2 or less  9  4 or less  0.35 
2+ to 5, inclusive  13  4+ to 12, inclusive  0.5 
5+ to 12, inclusive  19  12+ to 26, inclusive  0.75 
Over 12  25  Over 26  1.0 
 S.3.2.  Drainage.  – A load -receiving element intended to receive wet commodities shall be so 
constructed as to drain effectively.  
 
S.3.3.  Scoop Counterbalance.  – A scoop on a scale used for direct sales  to retail customers shall not be 
counterbalanced by a removable weight.  A permanently attached scoop -counterbalance shall indicate clearly on 
both the operator’s and customer’s sides of the scale whether it is positioned for the scoop to be on or off the  
scale.  
 
S.4. Design of Weighing Elements.  
 
S.4.1.  Antifriction Means.  – Frictional effects shall be reduced to a minimum by suitable antifriction 
elements.  Opposing surfaces and points shall be properly shaped, finished, and hardened.  A platform scale 
having a frame around the platform shall be equipped with means to prev ent interference between platform and 
frame.  
 
S.4.2.  Adjustable Components.  – An adjustable component such as a nose -iron or potentiometer shall 
be held securely in adjustment .  The position of a nose -iron on a sc ale of more than 1000 kg (2000 lb) capacity , 
as determined by the factory adjustment, shall be accurately, clearly, and permanently defined.  
(Amended 1986)  
 
S.4.3.  Multiple Load -Receiving Elements.  – Except for mechanical bench and counter scales, a scale 
with a single indicating or recording element, or a combination indicating -recording element, that is coupled to 
two or more load- receiving elements with independent weighing systems, shall be provided with means to 
prohibit the activation of  any load -receiving element (or elements) not in use, and shall be provided with 
automatic means to indicate clearly and definitely which load -receiving element (or elements) is in use.  
 
S.5. Design of Weighing Devices, Accuracy Class.  
 
S.5.1.  Designation of Accuracy Class.  – Weighing devices are divided into accuracy  classes and shall 
be designated as I , II, III, III L, or IIII . 
[Nonretroactive as of January  1, 1986]  
 
S.5.2.  Parameters for Accuracy Class.  – The accuracy  class  of a weighing device is designated by the 
manufacturer and shall comply with parameters shown in Table  3. 
[Nonretroactive as of January  1, 1986]  
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 S.5.3.  Multi -Interval and Multiple Range Scales, Division Value.  – On a multi -interval  scale and 
multiple range scale, the value of “e” shall be equal to the value of “d.”28 
(Added 1986) (Amended 1995)  
 
S.5.4.  Relationship of Load Cell Verification Interval Value to the Scale Division.  – The relationship of 
the value for the load cell  verification scale interval, v min, to the scale division,  d, for a specific scale installation 
using National Type Evaluation Program (NTEP) load cells shall comply with the fol lowing formulae where N 
is the number of load cells  in the scale (such as hopper or vehicle scale weighing/load- receiving elements):  
 
 
 (a)     for scales without lever systems; and  
   
 (b) for scales with lever systems.  
 
 
[*When the value of the scale division,  d, is different from the verification scale division,  e, for the 
scale, the value of e must be used in the formulae above.]  
 
This requirement does not apply to complete weighing/load- receiving elements or scales,  which satisfy all the 
following criteria:  
 
- the complete weighing/load- receiving element or scale has been evaluated for compliance with 
T.N.8.1. Temperature  under the NTEP;  
   
- the complete weighing/load- receiving element or scale has received an NTEP Certificate of 
Conformance ; and 
 
- the complete weighing/load -receiving element or scale is equipped with an automatic 
zero-tracking mechanism  which cannot be made inoperative in the normal weighing mode.  (A test 
mode which permits the disabling of the automatic zero- tracking mechanism is permissible, 
provided the scale cannot function normally while in this mode.  
[Nonretroactive as of January  1, 1994]  
(Added 1993) (Amended 1996)  
  
                                                           
28  Footnote  1 to Table  3 Parameters for Accuracy  Classes.  ) (*
minmultiple scale Ndv
×≤Ndv*
min≤2.20. Scales   Handbook 44 –  20152016  
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  Table 3.  
Parameters for Accuracy Classes  
Class  Value of the Verification Scale Division  
(d or e1) Number  of Scale4 Divisions (n)  
Minimum  Maximum  
SI Units  
I equal to or greater than 1 mg  50 000  -- 
II 1 to 50 mg, inclusive  100 100 000  
 equal to or greater than 100 mg  5 000  100 000  
III2,5 0.1 to 2 g, inclusive  100 10 000  
 equal to or greater than 5 g  500 10 000  
III L3 equal to or greater than 2 kg  2 000  10 000  
IIII equal to or greater than 5 g  100 1 200  
U.S. Customary Units  
III5 0.0002 lb to 0.005 lb, inclusive  100 10 000  
 0.005 oz to 0.125 oz, inclusive  100 10 000  
 equal to or greater than 0.01 lb  500 10 000  
 equal to or greater than 0.25 oz  500 10 000  
III L3 equal to or greater than 5 lb  2 000  10 000  
IIII greater than 0.01 lb  100 1 200  
 greater than 0.25 oz  100 1 200  
1 For Class  I and II devices equipped with auxiliary reading means (i.e., a rider, a vernier, or a least significant 
decimal differentiated by size, shape, or color), the value of the verification scale division “e” is the v alue of the 
scale division immediately preceding the auxiliary means.  
 
2 A Class III scale marked “For prescription  weighing only” may have a verification scale division (e) not less than 
0.01 g. 
(Added 1986) (Amended 2003)  
 
3 The value of a scale division for crane and hopper (other than grain hopper)  scales shall be not less than 0.2 kg 
(0.5 lb).  The minimum number of scale divisions shall be not less than 1000.  
 
4 On a multiple range or multi -interval scale, the number of divisions for each range independently shall not exceed 
the maximum specified for the accuracy  class .  The number of scale divisions,  n, for each weighing range is 
determined by dividing the scale capacity  for each range by the verification scale division,  e, for each range.  On a 
scale system with multiple load -receiving elements and multiple indications, each element considered shall not 
independently e xceed the maximum specified for the accuracy class.  If the system has a summing indicator,  the n max 
for the summed indication shall not exceed the maximum specified for the accuracy class.  
(Added 1997)  
 
5 The minimum number of scale divisions for a Class  III Hopper Scale used for weighing grain shall be 2000. ) 
[Nonretroactive as of January  1, 1986 ] 
(Amended  1986, 1987, 1997, 1998, 1999, 2003, and 2004)  Handbook 44 –  20152016   2.20.  Scales  
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  Agency No. 209.02  
 S.6. Marking Requirements.  – (Also see G -S.1. Identification, G -S.4. Interchange or Reversal of Parts, 
G-S.6. Marking Operational Controls, Indications, and Features, G -S.7. Lettering, G -UR.2.1.1. Visibility of 
Identification, and UR.3.4.1.  Use in Pairs.)  
 
S.6.1.  Nominal Capacity; Vehicle and Axl e-Load Scales.  – For all vehicle and axle -load scales , the 
marked nominal capacity  shall not exceed the concentrated load capacity  (CLC ) times the quantity of the 
number of sections in the scale minus  0.5. 
 
As a formula, this is stated as:  nominal capacity  < CLC × (N − 0.5)  
  where N = the number of sections in the scale.  
[Nonretroactive as of January  1, 1989]  
 
Note:   When the device is used in a combination railway track and vehicle weighing application, the above formula shall 
apply only to the vehicle scale application.  
(Added 1988) (Amended 1999 and 2002)  
 
S.6.2.  Location of Marking Information . – Scales that are not permanently attached to an indicating 
element , and for which the load -receiving element is the only part of the weighing/load -receiving element 
visible after installation, may have the marking information req uired in G-S.Section 1. of the 10. General Code, 
G-S.1. Identification  and S.6. of the Section 2.20.  Scales Code, S.6. Marking Requirements  located in an area 
that is accessible only through the use of a tool; provided that the information is easily accessib le (e.g., the 
information may appear on the junction box under an access plate).  The identification information for these 
scales shall be located on the weighbridge (load -receiving element) near the point where the signal leaves the 
weighing element or be neath the nearest access cover.  
(Added 1989)  
 
S.6.3.  Scales, Main Elements, and Components of Scales or Weighing Systems.  – Scales, main 
elements  of scales when not contained in a single enclosure for the entire scale, load cells  for which Certificates 
of Conformance (CC) have been issued under the National Type Evaluation  Program (NTEP), and other 
equipment necessary to a weighing system, but having no metrological effect on the weighing system, shall be 
marked as specified in Table S.6.3.a. Marking Requirements and explained in the accompanying notes in 
Table  S.6.3.b.  Notes for Table  S.6.3.a.  
(Added 1990)  
 
  2.20. Scales   Handbook 44 –  20152016  
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Table S.6.3.a.  
Marking Requirements  
 Weighing Equipment  
 
To Be Marked With ⇓ 
 
 
 
 Weighing, 
Load -
Receiving, and 
Indicating 
Element  in 
Same Housing 
or Covered on 
the Same CC1 Indicating 
Element not 
Permanently 
Attached to 
Weighing and 
Load -Receiving 
Element or 
Covered by a 
Separate CC  Weighing and 
Load -Receiving 
Element Not 
Permanently 
Attached to 
Indicating 
Element or 
Covered by a 
Separate CC  Load Cell 
with CC  
(11) Other 
Equipment 
or Device  
(10) 
Manufacturer’s ID  (1) X X X X  X 
Model Designation and Prefix  (1) X X X X  X 
Serial Number and Prefix  (2) X X X X  X (16)  
Certificate of Conformance Number 
(CC)  (23) X X X X  X (23)  
Accuracy  Class  (17) X  X (8)   X (19)  X  
Nominal Capacity  (3)(18)(20)  X X X   
Value of Scale Division, “d”  (3) X X    
Value of “e”  (4) X X    
Temperature  Limits  (5) X X X X  
Concentrated Load Capacity  (CLC)
 (12)(20)(22)   X  X (9)    
Special Application  (13) X X X   
Maximum Number of Scale 
Divisions (n max) (6)   X (8)   X (19)  X  
Minimum Verification Scale 
Division (e min)    X (19)    
“S” or “M”  (7)    X  
Direction of Loading  (15)    X  
Minimum Dead Load     X  
Maximum Capacity     X  
Safe Load Limit     X  
Load Cell  Verification Interval  
(vmin) (21)    X  
Section Capacity  and Prefix
 (14)(20)(22)(24)   X X   Handbook 44 –  20152016   2.20.  Scales  
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 Table S.6.3.a.  
Marking Requirements  
Note:   For applicable notes, Table S.6.3.b.  
1 Weighing/load -receiving elements and indicators which are in the same housing or which are permanently attached 
will generally appear on the same CC.  If not in the same housing, elements shall be hard -wired together or sealed 
with a physical seal or an electronic link.  This requirement does not apply to peripheral equipmen t that has no input 
or effect on device calibrations or configurations.  
(Added 2001)  
(Added 1990) (Amended 1992, 1999, 2000, 2001, 2002, and 2004)  
 
Table S.6.3.b.  
Notes for Table S.6.3.a. Marking Requirements  
1. Manufacturer's identification and model designation and model designation prefix.*  
[*Nonretroactive as of January  1, 2003 ] 
(Also see G -S.1. Identification.)  [Prefix lettering may be initial capitals, all capitals or all lower case]  
(Amended 2000)  
 
2. Serial number [Nonretroactive as of January  1, 1968] and prefix [Nonretroactive as of January  1, 1986].  (Also see 
G-S.1. Identification.)  
 
3. The device shall be marked with the nominal capacity.   The nominal capacity shall be shown together with the value of 
the scale division (e.g., 15  × 0.005  kg, 30 × 0.01 lb, or capacity  = 15 kg, d  = 0.005 kg) in a clear and conspicuous 
manner and be readily apparent when viewing the reading face of the scale indicator unless  already apparent by the 
design of the device.  Each scale division value or weight unit shall be marked on multiple range or multi -interval  
scales.   
 [Nonretroactive as of January  1, 1983]  
(Amended 2005)  
 4. Required only if different fr om “d.”   
 [Nonretroactive as of January  1, 1986]  
 
5. Required only on Class  III, III L, and  IIII devices if the temperature range on the NTEP CC is narrower than and 
within −  10 °C to 40 °C (14  °F to 104 °F).  [Nonretroactive as of January  1, 1986]  
(Amended 1999)  
 
6. This value may be stated on load cells  in units of 1000; e.g., n:  10 is 10  000 divisions.   
[Nonretroactive as of January  1, 1988]  
 
7. Denotes compliance for single or multiple load cell  applications.  It is acceptable to use a load cell with the “S” or 
Single Cell designation in multiple load cell applications as long as all other parameters meet applicable 
requirements.  A load cell  with the “M” or Multiple Cell designation can be used only in multiple load cell 
applications.  
 [Nonretroactive as of January  1, 1988]  
(Amended 1999)  
 
8. An indicating element  not permanently attached to a weighing element shall be clearly and permanently marked with 
the accuracy Class  of I, II, III, III L, or IIII, as appropriate, and the maximum number of scale divisions, n max, for 
which the indicator  complies with the applicable requirement.  Indicating elements that qualify for use in both 
Class  III and III L applications may be marked III/III  L and shall be marked with the maximum number of scale 
divisions for whic h the device complies with the applicable requirements for each accuracy class .   
 [Nonretroactive as of January  1, 1988]  
 
 2.20. Scales   Handbook 44 –  20152016  
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 Table S.6.3.b.  
Notes for Table S.6.3.a. Marking Requirements  
 
9. For vehicle and axle -load scales  only.  The CLC  shall be added to the load- receiving element of any such scale not 
previously marked at the time of modification.   
 [Nonretroactive as of January  1, 1989]  
(Amended 2002)  
 
10. Necessary to the weighing system but having no metrological effect, e.g., auxiliary  remote display, keyboard, etc.  
 
11. The markings may be either on the load cell  or in an accompanying document; except that, if an accompanying 
document is provided, the serial number shall appear both on the load cell and in the document.  [Nonretroactive as of 
January  1, 1988]  The manufacturer’s name or trademark, the model designation, and identifying symbols for the 
model and serial numbers as required by paragraph  G-S.1. Identification shall also be marked both on the load cell 
and in any accompanying document.  
 [Nonretroactive as of January  1, 1991]  
 12. Required on the indicating element  and the load- receiving element  of vehicle and axle -load scales .  Such marking 
shall be ide ntified as “concentrated load capacity”  or by the abbreviation “CLC.” *   
 [*Nonretroactive as of January  1, 1989]  
(Amended 2002)  
 
13. A scale designed for a special application rather than general use shall be conspicuously marked with suitable words, 
visible to the operator and to the customer, restricting its use to that application, e.g., postal  scale, prepack scale, 
weight classifier , etc.*   When a scale is installed with an operational count ing feature, the scale shall be marked on 
both the operator and customer sides with the statement “The counting feature  is not legal for trade,” except when a 
Class  I or Class  II prescription  scale complies with all Handbook  44 requirements applicable to counting features.  
[*Nonretroactive as of 1986]   
(Amended 1994 and 2003)  
 
14. Required on livestock*  and railway track scales.   When marked on vehic le and axle- load scales  manufactured before 
January  1, 1989, it may be used as the CLC .  For livestock scales manufactured between January  1, 1989, and 
January  1, 2003, required markings may be either CLC or section capacity.   
 [*Nonretroactive as of January  1, 2003]  
(Amended 2002)  
 
15. Required if the direction of loading the load cell  is not obvious.  
 [Nonretroactive as of January  1, 1988]  
 
16. Serial number [Nonretroactive as of January  1, 1968] and prefix [Nonretroactive as of January  1, 1986].   (Also see 
G-S.1. Identification.)  Modules without “intelligence” on a modular syste m (e.g., printer, keyboard module, cash 
drawer, and secondary display in a point -of-sale system) are not required to have serial numbers.  
 
17. The accuracy class  of a device shall be marked on the device with the appropriate designation as I,  II, III, III L, or 
IIII. 
[Nonretroactive as of January  1, 1986]  
 18. The nominal capacity  shall be conspicuously marked as follows:  
(a) on any scale equipped with unit weights or weight ranges ; 
(b) on any scale with which counterpoise or equal -arm weights are intended to be used;  
(c) on any automatic -indicating or recording scale so constructed that the capacit y of the indicating or recording 
element, or elements, is not immediately apparent;  
(d) on any scale with a nominal capacity  less than the sum of the reading elements; and  
(e) on the load- receiving element (weighbridge) of vehicle, axle -load, and livestock scales .* 
[*Nonretroactive as of January  1, 1989]  
(Amended 1992)  Handbook 44 –  20152016   2.20.  Scales  
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  Agency No. 209.02  
 Table S.6.3.b.  
Notes for Table S.6.3.a. Marking Requirements  
 
19. For weighing and load- receiving elements not permanently attached to indicat ing element or covered by a separate 
CC. 
[Nonretroactive as of January,  1, 1988]  
(Amended 1992)  
 
20. Combination vehicle/railway track scales  must be marked with both the nominal capacity  and CLC  for vehicle 
weighing and the nominal capacity  and section capacity for railway weighing.  All other requirements relating to 
these markings will apply.  
[Nonretroactive as of January  1, 2000]  
(Added 1999)  
 
21. The value of the load cell  verification interval  (vmin) must be stated in mass units.  In addition to this information, a 
device may be marked with supplemental representations of v min. 
[Nonretroactive as of January  1, 2001]  
(Added 1999)  
 
22. Combination vehicle/livestock scales  must be marked with both the CLC for vehicle weighing and the section capacity 
for livestock weighing.  All other requirements relative to these markings will apply.   
 [Nonret roactive as of January  1, 2003]  
(Added 2002) (Amended 2003)  
 
Note:  The marked section capacity for livestock weighing may be less than the marked CLC for vehicle weighing.  
(Amended  2003)  
 
23. Required only if a CC has been issued for the device or equipment.   
[Nonretroactive as of January  1, 2003]  
(G-S.1. Identification (e) Added 2001)  
 
24. The section capacity shall be prefaced by the words “Section Capacity” or an abbreviation of that term.  
Abbreviations shall be “Sec Cap” or “Sec  C.”  All capital letters and periods may be used.  
[Nonretroactive as of January  1, 2005]  
(Added 2004)  
 
 
S.6.4.  Railway Track Scales.  – A railway track scale shall be marked with the maximum capacity  of 
each section of the load -receiving element of the scale.  Such marking shall be accurately and conspicuously 
presented on, or adjacent to, the identification or nomenclatur e plate that is attached to the indicating element  of 
the scale.  The nominal capacity marking shall satisfy the following:  
(a) For scales manufactured from January 1, 2002, through December 31, 2013:  
 
(1) the nominal capacity of a scale wi th more than two sections shall not exceed twice its rated section 
capacity; and  
(2) the nominal capacity of a two section scale shall not exceed its rated section capacity.  
(b) For scales manufactured on or after January 1, 2014, the nominal scale capacity shall not exceed the 
lesser of:  
(1) the sum of the Weigh Module Capacities as shown in Table S.6.4.M. and Table S.6.4.; or  2.20. Scales   Handbook 44 –  20152016  
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 (2) the Rated Section Capacity (RSC) multiplied by the Number of Sections (Ns) minus the Number 
of Dead Spaces (Nd) minus 0.5.  As a formula this i s stated as:  
RSC × (Ns –  Nd – 0.5);  or 
(3) 290 300 kg (640 000  lb). 
(Amended 1988, 2001, 2002, and 2013)  
 
Table S.6.4.M.  
Railway Track Scale – Weigh Module Capacity  
Weigh Module Length  
(meters)  Weigh Module Capacity  
(kilograms)  
< 1.5  36 300  
1.5 to < 3.0  72 600 
3.0 to < 4.5  108 900  
4.5 to < 7.0  145 100  
7.0 to < 9.0  168 700  
9.0 to < 10.5  192 300  
10.5 to < 12.0  234 100  
12.0 to < 17.0  257 600  
Note:  The capacity of a particular module is based on its length as shown above.  To determine the “sum of 
the weigh module capacities” referenced in paragraph S.6.4.(b)(1):   (1) determine the length of each 
individual weigh module in the scale; (2) find its corresponding “weigh module capacity” in the table above; 
and (3) add all of the individual weigh module capacities.”  
(Table Added 2013)  
Table S.6.4.  
Railway Track Scale – Weigh Module Capacity  
Weigh Module Length  
(feet)  Weigh Module Capacity  
(pounds)  
< 5 80 000  
5 to < 10  160 000  
10 to < 15  240 000  
15 to < 23  320 000  
23 to < 29  372 000  
29 to < 35  424 000 
35 to < 40  516 000  
40 to < 56  568 000  
Note:  The capacity of a particular module is based on its length as shown above.  To determine the “sum of 
the weigh module capacities” referenced in paragraph S.6.4.(b)(1):   (1) determine the length of each 
individual weigh module in the scale; (2) find its corresponding “weigh module capacity” in the table above; 
and (3) add all of the individual weigh module capacities.”  
(Table Added 2013)  
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 S.6.5.  Livestock Scales.  – A livestock scale manufactured prior to January  1, 1989, or after 
January  1, 2003, shall be marked with the maximum capacity of each section of the load -receiving element of 
the scale.  Livestock scales  manufactured between January  1, 1989, and January  1, 2003, shall be marked with 
either the Concentrated Load Capacity (CLC) or the Section Capacity.  Such marking shall be accurately and 
conspicuously presented on, or adjacent to the identification or nomenclature plate that is attache d to the 
indicating element  of the scale.  The nominal capacity of a scale with more than two sections shall not exceed 
twice its rated section capacity.  The nominal capacity of a two- section scale shall not exceed its rated sectio n 
capacity. * 
[*Nonretroactive as of January  1, 2003]  
(Added 2002)  
 
Also see Note  14 in Table  S.6.3.b. Notes for Table  S.6.3.a.  
 
S.6.6.  Counting Feature, Minimum Individual Piece Weight, and Minimum Sample Piece Count. –  
A Class  I or Class  II prescription  scale with an operational counting feature shall be marked with the minimum 
individual piece weight and minimum number of pieces used in the sample to establish an individual piece weight.  
(Added 2003)  
 
N. Notes  
 
N.1. Test Procedures.  
 N.1.1.  Increasing -Load Test.  – The increasing -load test shall be conducted on all scales with the test 
loads  approximately centered on the load -receiving element of the scale, except on a scale having a nominal 
capacity  greater than the total available known test load.  When the total test load is less than the nominal 
capacity , the test load is used to greatest advantage by concentrating it, within prescribed load limits, over the 
main load supports  of the scale.  
 
N.1.2.  Decreasing -Load Test (Automatic Indicating Scales).  – The decreasing -load test shall be 
conducted with the test load approximately centered on the load -receiving element of the scale.  
 
N.1.2.1.  Scales Marked I, II, III, or IIII.  – Except for portable wheel load weighers, decreasing -load 
tests shall be conducted on scales marked I, II, III or IIII and with “n” equal to or greater than 1000 with 
test loads  equal to the maximum test load at each tolerance value.  For example, on a Class  III scale, at test 
loads equal to 4000 d, 2000  d, and 500 d; for scales with n less than 1000, the test load sh all be equal to 
one-half of the maximum load applied in the increasing -load test.  (Also see Table  6. Maintenance 
Tolerances.)  
(Amended 1998)  
 
N.1.2.2.  All Other Scales.  – On all other scales, except for portable wheel load weighers, the 
decreasing -load te st shall be conducted with a test load equal to one -half of the maximum load applied in 
the increasing -load test.  
(Amended 1998)  
 
N.1.3.  Shift Test.  
 
N.1.3.1.  Dairy -Product Test Scales.  – A shift test  shall be conducted with a test load of 18 g 
successively positioned at all points on which a weight might reasonably be placed in the course of normal use of the scale.  
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 N.1.3.2.  Equal -Arm Scales.  – A shift test shall be conducted with a half -capacity  test load centered 
successively at four points positioned equidistance between the center and the front, left, back, and right edges of each pan as shown in the diagrams below.  An equal test load shall be centered on the other pan.  
 
 
N.1.3.3.  Vehicle Scales, Axle -Load Scales, and Livestock Scales.  
 
N.1.3.3.1.  Vehicle Scales, Axle- Load Scales, and Combination Vehicle/Livestock Scales.  
 
(a) Minimum Shift Test.  – At least one shift test shall be conducted with a minimum test load of 
12.5 % of scale capacity, which may be performed anywhere on the load -receiving element 
using the prescribed test patterns  and maximum test loads  specified below.  (Combination 
Vehicle/Livestock Scales shall also be tested consistent with N.1.3.3.2. Prescribed Test 
Pattern and Test Loads for Livestock Scales with More Than Two Sections and Combination 
Vehicle/Livestock Scales.)  
(Amended 1991, 2000, and 2003)  
 
(b) Prescribed Test Pattern and Loading for Vehicle Scales, Axle- Load Scales, and 
Combination Vehicle/Livestock Scales.  – The normal prescribed test pattern  shall be an area 
of 1.2 m (4  ft) in length and 3.0 m (10  ft) in width or the width of the scale platf orm, 
whichever is less.  Multiple test patterns may be utilized when loaded in accordance with paragraph  (c), (d), or  (e) as applicable.  An example of a possible test pattern is shown in the 
diagram below.  
(Amended 1997, 2001, and 2003)  
 
4’  4’  4’  4’  4’ 
             
             
Section  
1   Midway between 
sections 1 and 2   Section  
2  Midway between 
sections 2 and 3   Section 
3 
 
(c) Loading Precautions for Vehicle Scales, Axle- Load Scales, and Combination 
Vehicle/Livestock Scales.  – When loading the scale for testing, one side of the test pattern  
shall be loaded to no more than half of the concentrated load capacity  or test load before 
loading the other side.  The area covered by the test load may be less than 1.2  m (4 ft) × 3.0 m 
(10 ft) or the width of the scale platform, whichever is less; for test patterns less than 1.2  m 
(4 ft) in length the maximum loading shall meet the formula:  [(wheel base of test cart or 
length of test load divided by 48 in) × 0.9 × CLC ].  The maximum test load applied to each 
test pattern shall not exceed the concentrated lo ad capacity of the scale.  When the test pattern 
exceeds 1.2  m (4  ft), the maximum test load applied shall not exceed the concentrated load 
capacity times the largest “r” factor in Table UR.3.2.1.  Span Maximum Load for the length of 
the area covered by the test load.  For load- receiving elements  installed prior to 
January  1, 1989, the rated section capacity may be substituted for concentrated load capacity 
to determine maximum loading.  An example of a possible test pattern is shown a bove.  
(Amended 1997 and 2003)  
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 (d) Multiple Pattern Loading.  – To test to the nominal capacity,  multiple patterns may be 
simultaneously loaded in a manner consistent with the method of use.  
 
(e) Other Designs.  – Special design scales and those that are wider than 3.7  m (12  ft) shall be 
tested in a manner consistent with the method of use but following the principles described 
above.  
(Amended 1988, 1991, 1997, 2000, 2001, and 2003)  
(Amended 2003)  
 
N.1.3.3.2.  Prescribed Test Pattern and Test Loads for Livestock Scales with More Than Two 
Sections and Combination Vehicle/Livestock Scales.  – A minimum test load of 5 000 kg (10  000 lb) 
or one -half of the rated section capacity, whichever is less, shall be placed, as nearly as possible, 
successively over each main load support as shown in the diagram below.  For livestock scales  
manufactured between January  1, 1989, and January  1, 2003, the required loading shall be no greater 
than one -half CLC.  (Two -section livestock scales  shall be tested consistent with N.1.3.7.  All Other 
Scales Except Crane Scales, Hanging Scales, Hopper Scales, Wheel -Load Weighers, and Portable 
Axle -Load Weighers.)  
 
     
  
 
Position 1    
 
Position 2     
 
Position 3   
       
           
Position 6  
 
 
  Position 5  
 
  
  Position 4  
 
 
     
 
 = Load Bearing Point  
(Added 2003)  
 
N.1.3.3.3.  Prescribed Test Patterns and Test Loads for Two -Section Livestock Scales. –  A shift 
test shall be conducted using the following prescribed test loads and test patterns, provided the shift 
test load does not exceed one -half the rated section capacity or one -half the rated concentrated load 
capacity whichever is applicable, using either:  
 
(a) A one -half nominal capacity test load centered as nearly as possible, su ccessively at the center 
of each quarter of the load -receiving element as shown in N.1.3.7.  All Other Scales Except 
Crane Scales, Hanging Scales, Hopper Scales, Wheel -Load Weighers, and Portable 
Axle -Load Weighers Figure  1; or 
 (b) A one -quarter nominal capacity test load centered as nearly as possible, successively over 
each main load support as shown in N.1.3.7.  All Other Scales Except Crane Scales, Hanging 
Scales, Hopper Scales, Wheel -Load Weighers, and Portable Axle -Load Weighers Figure  2. 
 (Added 2007)  
 
N.1.3.4.  Railway Track Scales Weighing Individual Cars in Single Drafts.  – A shift test shall be 
conducted with at least two different test loads , if available, distributed over, to the right and left of, each 
pair of main levers or other weighing elements  supporting each section of the scale.  
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 N.1.3.5.  Monorail Scales, Static Test.  – A shift test shall be conducted with a test load equal to the 
largest load that can be anticipated to be weighed in a given installation, but never less than one -half scale 
capacity .  The load shall be placed successively on the right end, the left end, and the center of the live rail.  
(Added 198 5) 
 
N.1.3.5.1.  Dynamic Monorail Weighing Systems.  – Dynamic tests with livestock carcasses or 
portions of carcasses shall be conducted during normal plant production.  No less than 20 test loads 
using carcasses or portions of carcasses of the type normally  weighed shall be used in the dynamic test.  
If the plant conveyor chain does not space or prevent the carcasses or portions of carcasses from 
touching one another, dynamic tests shall not be conducted until this condition has been corrected.  
 
All carcasse s or portions of carcasses shall be individually weighed statically on either the same scale 
being tested dynamically or another monorail scale with the same or smaller divisions and in close 
proximity.  (The scale selected for static weighing of the carcasses or portions of carcasses shall first 
be tested statically with certified test weights that have been properly protected from the harsh 
environment of the packing plant to ensure they maintain accuracy.)  
 
If the scale being tested is used for weighing freshly slaughtered animals (often referred to as a “hot 
scale”), care must be taken to get a static weighment as quickly as possible before or following the dynamic weighment to avoid loss due to shrink.  If multiple dynamic tests are conducted using the 
same carcasses or portions of carcasses, static weights shall be obtained before and after multiple 
dynamic tests.  If the carcass or portion of a carcass changes weight between static tests, the amount of 
weight change shall be taken into account, or the carcass or portion of a carcass shall be disregarded 
for tolerance purposes.  
 
Note:   For a dynamic monorail test, the reference scale shall comply with the principles in the Fundamental 
Considerations paragraph 3.2. Tolerances for Standards . 
(Added 1996) (Amended 1999 and 2007)  
 
N.1.3.6.  Vehicle On -Board Weighing Systems.  – The shift test  for a vehicle on -board weighing system  
shall be conducted in a manner consistent with its normal use.  For systems that weigh as part of the lifting 
cycle, the center of gravity of the load may be shifted in the vertical direction as well as from side to side.  
In other cases, the center of gravity may be moved to the extremes of the load -receiving element  using 
loads of a magnitude that reflect normal use (i.e., the load for the shift test may exceed one -half scale 
capacity ), and may, in some cases, be equal to the capacity of the scale.  The shift test may be conducted 
when the weighing syst em is out of level  to the extent that the weighing system remains operational.  
(Added 1992)  
 
N.1.3.7.  All Other Scales Except Crane Scales, Hanging Scales, Hopper Scales, Wheel -Load 
Weighers, and Portable Axle- Load Weighers.  – A shift test shall be conducted using the following 
prescribed test loads and test patterns.  A single field standard weight used as the prescribed test load shall 
be applied centrally in the prescribed test pattern.  When  multiple field standard weights are used as the 
prescribed test load, the load shall be applied in a consistent pattern in the  shift test positions throughout the 
test and applied in a manner that does not concentrate the load in a test pattern that is less than when that 
same load is a single field standard weight on the load- receiving element.  
 
(a) For scales with a nominal capacity of 500  kg (1000 lb) or less, a shift test shall be conducted using 
a one -third nominal capacity test load (defined as test weights in amounts of at least 30  % of scale 
capacity, but not to exceed 35  % of scale capacity) centered as nearly as possi ble at the center of 
each quadrant of the load -receiving element using the prescribed test pattern as shown in Figure  1. 
 
(b) For scales with a nominal capacity greater than 500  kg (1000 lb), a shift test may be conducted by 
either using a one -third nomina l capacity test load (defined as test weights in amounts of at least 
30 % of scale capacity, but not to exceed 35  % of scale capacity) centered as nearly as possible at 
the center of each quadrant of the load -receiving element using the prescribed test pat tern as Handbook 44 –  20152016   2.20.  Scales  
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 shown in Figure  1, or by using a one -quarter nominal capacity test load centered as nearly as 
possible, successively, over each corner of the load -receiving element using the prescribed test 
pattern as shown in Figure  2. 
 
Figure 1                                                                   Figure 2  
  
  
  
   
  
 Position 
1 
  Position 
2  
 
 Position 
1  Position 
2  
 
 
 
    
 
   
 
 
  
  
  
  
  
  
 
 Position 
4  Position 
3  
 
 
 
 Position 
4  Position 
3  
 
   
 
 
   
(Added 2003)  
(Amended 1987, 2003, and 2007)  
 
N.1.4.  Sensitivity Test.  – A sensitivity test  shall be conducted on nonautomatic -indicating (weighbeam) 
scales only, with the weighing device in equilibrium at zero -load and at maximum test load.  The test shall be 
conducted by increasing or decreasing the test load in an amount equal to the applicable value specified in 
T.2. Sensitivity Requirement (SR) or T.N.6.  Sensitivity.  
 N.1.5.  Discrimination Test.  – A discrimination test shall be conducted on all automatic indicating scales  
with the weighing device in equilibrium at or near zero load and at or near maximum test load, and under 
controlled conditions in which environmental factors  are reduced to the extent that they will not affect the 
results obtained.  F or scales equipped with an Automatic Zero- Tracking Mechanism  (AZT), the discrimination 
test may be conducted at a range outside of the AZT range.  
[Nonretroactive as of January  1, 1986]  
(Added 1985) (Amended 2004)  
 
N.1.5.1.  Digital Device.  – On a digital device, this test is conducted from just below the lower edge of 
the zone of uncertainty for increasing load tests, or from just above the upper edge of the zone of 
uncertainty for decreasing -load tests.  
 
N.1.6.  RFI Susceptibility Tests, Field Evaluation.  – An RFI test shall be conducted at a given 
installation when the presence of RFI has been verified and characterized if those conditions are considered 
“usual and customary.”  
(Added 1986)  
 
N.1.7.  Ratio Test.  – A ratio test shall be conducted on all scales employing counterpoise weights and on 
nonautomatic -indicating equal -arm scales.  
 
N.1.8.  Material Tests.  – A material test shall be conducted on all customer -operated bulk weighing 
systems for recycled materials using bulk material for which the device is used.  Insert into the device, in a 
normal manner, several accurately pre- weighed samples (free of foreign material) in varying amounts 
approximating average drafts.  
 
N.1.9.  Zero -Load Balance Change.  – A zero -load balance change test shall be conducted on all scales 
after the removal of any test load.  The zero -load balance should not change by more tha n the minimum 
tolerance applicable.  (Also see G -UR.4.2. Abnormal Performance.)  2.20. Scales   Handbook 44 –  20152016  
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N.1.10.  Counting Feature Test.  – A test of the counting function shall be conducted on all Class  I and 
Class  II prescription  scales having an active counting feature used in “legal for trade” applications.  The test 
should verify that the scale will not accept a sample with less than either the minimum sample piece count or 
the minimum sample weight of 30  e.  Counting feature accuracy should be verified at a minimum of two test 
loads.  Verification of the count calculations shall be based upon the weight indication of the test load.  
 
Note:  
(1) The minimum sample weight is equal to the marked minimum individual piece weight times the marked minimum 
sample piece count.  
(2) Test load as used in this section refers to actual calibration test weights selected from an appropriate test weight class.  
(Added 2003)  
 
N.1.11.  Substitution Test.  – In the substitution test procedure, material or objects are substituted for 
known test weights, or a combination of known test weights and previously quantified material or objects, using the scale under test as a comparator.  Additional test weights or other known test load s may be added to the 
known test load to evaluate higher weight ranges on the scale.  
(Added 2003)  
 
N.1.12.  Strain- Load Test.  – In the strain -load test procedure, an unknown quantity of material or objects 
are used to establish a refer ence load or tare to which test weights or substitution  test loads are added.  
(Added 2003)  
 
N.2. Verification (Testing) Standards.  – Field standard  weights used in verifying weighing devices shall comply 
with requireme nts of NIST Handbook  105-Series standards (or other suitable and designated standards) or the 
tolerances  expressed in Fundamental Considerations, paragraph  3.2. (i.e., one -third of the smallest tolerance 
applied).  
(Amended 1986)  
 
N.3. Minimum Test Weights and Test Loads.  – The minimum test weights  and test loads  for in -service tests 
(except railway track scales ) are shown in Table 4. (Also see Footnote  2 in Table  4. Minimum Test Weights and 
Test Loads.)  
(Added 1984) (Amended 1988)  
 
N.3.1.  Minimum Test -Weight Load and Tests for Railway Track Scales.  
(Amended 1990 and 2012)  
 
N.3.1.1.  Initial and Subsequent Tests.  – The test -weight load shall be not less than 35  000 kg 
(80 000 lb).  A strain -load test  conducted up to the used capacity  of the weighing system is recommended.  
(Added 1990) (Amended 2012)  
 
N.3.1.2.  Interim Test.  – An Interim Test may be used to return a railway track scale into temporary 
service following repairs that could affect the accuracy of the weighing system providing all of the following conditions are met:  
 
(a) a test weight load of not less than 13 500 kg (30 000 lb) shall be used;  
 
(b) a shift (section) test shall be conducted using a test -weight load of not less than 13 500 kg 
(30 000 lb); 
 
(c) a strain -load test shall be conducted up to at least 25 % of scale capacity;  
 
(d) all test results shall be withi n applicable tolerances; and  Handbook 44 –  20152016   2.20.  Scales  
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(e) the official with statutory authority shall be immediately notified when scales are repaired and 
placed in temporary service with an Interim Test.  The length of temporary service following 
repair is at the discretion of the official with statutory authority.  
  (Added 1990) (Amended 2012)  
 
N.3.1.3.  Enforcement Action for Inaccuracy.  – To take enforcement action on a scale that is found to 
be inaccurate, a minimum test load of 13  500 kg (30  000 lb) must be used.  
(Added 1990)  
 
Table 4.  
Minimum Test Weights  and Test Loads1 
Devices in Metric Units  
 Devices in U.S. Customary Units  
Device Capacity  
(kg)  Minimums  
(in terms of device capacity)  Device Capacity  
(lb) Minimums  
(in terms of device capacity)  
Test Weights 
(greater of)  Test 
Loads2 Test Weights  
(greater of)  Test  
Loads2 
0 to 150  kg 100 %   0 to 300  lb 100 %  
151 to 1  500 kg 25 % or 150  kg 75 %  301 to 3  000 lb 25 % or 300  lb 75 % 
1 501 to 20  000 kg 12.5 % or 500  kg 50 %  3001 to 40  000 lb 12.5 % or 1  000 lb 50 % 
20 001 kg+ 12.5 % or 5  000 kg 25 %3  40 001 lb+  12.5 % or 10  000 lb 25 %3 
Where practicable:  
 
• Test weights to dial face capacity, 1000  d, or test load to used capacity, if greater than minimums specified.  
• During initial verification,  a scale should be tested to capacity.  
1 If the amount of test weight in Table 4 combined with the load on the scale would result in an unsafe condition, 
then the appropriate load w ill be determined by the official with statutory authority.  
 
2 The term “test load” means the sum of the combination of field standard  test weights and any other applied load 
used in the conduct of a test using substitution  test methods.  Not more than three substitutions shall be used during 
substitution testing, after which the tolerances  for strain load tests shall be applied to each set of test loads . 
 
3 The scale shall be tested from  zero to at least 12.5  % of scale capacity  using known test weights and then to at least 
25 % of scale capacity using either a substitution or strain load test that utilizes known test weights of at least 12.5  % 
of scale capacity.  Whenever p ractical, a strain load test should be conducted to the used capacity of the scale.  When 
a strain load test is conducted, the tolerances apply only to the test weights or substitution  test loads.  
(Amended 1988, 1989, 1994, and 2003)  
 
Note:  GIPSA requires devices subject to their inspection to be tested to at least “used capacity,” which is calculated 
based on the platform area of the scale and a weight factor assigned to the species of animal weighed on the scale.  “Used capacity” is cal culated using the formula:  
 
Used Scale Capacity  = Scale Platform Area x Species Weight Factor  
 
Where species weight factor  = 540 kg/m2 (110 lb/ft2) for cattle, 340  kg/m2 (70 lb/ft2) for calves and hogs, and 
240 kg/m2 (50 lb/ft2) for sheep and lambs.  
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 N.3.2.  Field Standard Weight Carts.  – Field Standard  Weight Carts that comply with the tolerances 
expressed in Fundamental Considerations, paragraph  3.2. (i.e., one -third of the smallest tolerance applied) may 
be included as part of the minimum required test load (Also see Table  4. Minimum Test Weights and Test 
Loads.) for shift tests  and other test procedures.  
(Added 2004)  
 
N.4.  Coupled- in-Motion Railroad Weighing Systems.29 
 
N.4.1.  Weighing Systems Used to Weigh Trains of Less Than Ten Cars.  – These weighing systems 
shall be tested using a consecutive- car test  train consisting of the number of cars weighed in the normal 
operation run over the weighing system a minimum of five times in each mode of operation following the final 
calibration.  
(Added 1990) (Amended 1992)  
 
N.4.2.  Weighing Systems Placed in Service Prior to January  1, 1991, and Used to Weigh Trains of 
Ten or More Cars.  – The minimum test tra in shall be a consecutive -car test  train of no less than ten cars run 
over the scale a minimum of five times in each mode of operation following final calibration.  
(Added 1990) (Amended 1992)  
 
N.4.3.  Weighing Systems Placed in Ser vice on or After January  1, 1991, and Used to Weigh Trains 
of Ten or More Cars.  
 
(a) These weighing systems shall be tested using a consecutive -car test  train of no less than ten cars run 
over the scale a minimum of five times in each mode of operation following final calibration; or  
 
(b) if the official with statutory authority determines it necessary, the As -Used Test Procedures outlined in 
N.4.3.1. shall be used.  
 (Added 1990) (Amended 1992)  
 
N.4.3.1.  As-Used Test Procedures  – A weighing system shall be tested in a manner that represents the 
normal method of operation and length(s) of trains normally weighed.  The weighing systems may be tested using either a:  
 
(a) consecutive -car test  train of a len gth typical of train(s) normally weighed; or  
 
(b) distributed -car test  train of a length typical of train(s) normally weighed.  
 
However, a consecutive -car test  train of a shorter length may be used, provided that initial verification  test 
results for the shorter consecutive -car test train agree with the test results for the distributed -car or 
full-length consecutive -car test train as sp ecified in N.4.3.1.1. Initial Verification.  
 The official with statutory authority shall be responsible for determining the minimum test train length to 
be used on subsequent tests.  
(Added 1990) (Amended 1992)  
 
                                                           
29 A test weight car that is representative of one of the types of cars typically weighed on the scale under test may 
be used wherever reference weight cars are specified.  
(Added 1991)  
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 N.4.3.1.1.  Initial Verification.  – Initial verification tests should be performed on any new weighing 
system and whenever either the track structure or the operating procedure changes.  If a 
consecutive -car test  train of length shorter than trains normally weighed is to be used for subsequent 
verification,  the shorter consecutive -car test train results shall be compared either to a distributed -car 
or to a consecutive -car test train of length(s) typical of train(s) normall y weighed.  
 
The difference between the total train weight of the train(s) representing the normal method of 
operation and the weight of the shorter consecutive -car test  train shall not exceed 0.15  %.  If the 
difference in test res ults exceeds 0.15  %, the length of the shorter consecutive -car test train shall be 
increased until agreement within 0.15  % is achieved.  Any adjustments to the weighing system based 
upon the use of a shorter consecutive -car test train shall be offset to co rrect the bias that was observed 
between the full -length train test and the shorter consecutive -car test train.  
(Added 1990) (Amended 1992 and 1993)  
 
N.4.3.1.2.  Subsequent Verification.  – The test train may consist of either a consecutive -car test  
train with a length not less than that used in initial verification,  or a distributed -car test  train 
representing the number of cars used in the normal operation.  
(Added 1990)  
 
N.4.3.1.3.  Distributed- Car Test Trains.  
 
(a) The length of the train shall be typical of trains that are normally weighed.  
 
(b) The reference weight cars shall be split into three groups, each group consisting of ten cars or 
10 % of the  train length, whichever is less.  
(Amended 1991)  
 
(c) The test groups shall be placed near the front, around the middle, and near the end of the train.  
 (d) Following the final adjustment , the distributed -car test  train shall be run over the scale at least 
three times or shall produce 50  weight values, whichever is greater.  
 
(e) The weighing system shall be tested in each mode of operation.  
(Added 1990) (Amended 1992)  
 
N.4.3.1.4.  Consecutive -Car Test Trains.  
 
(a) A consecutive -car test  train shall consist of at least ten cars.  
 
(b) If the consecutive -car test  train consists of between ten and twenty cars, inclusive, it shall be 
run over the scale a minimum of five times in each mode of operation following the final 
calibration.  
 
(c) If the consecutive -car test  train consists of more than twenty cars, it shall be run over the scale 
a minimum of three times in each mode of operation.  
(Added 1990) (Amended 1992)  
 
N.5. Uncoupled- in-Motion Railroad Weighing System.  – An uncoupled -in-motion  scale shall be tested statically 
before being tested in motion by passing railroad reference weight cars over the scale.  When an uncoupled -in-motion 
railroad weighing system is tested, the car speed and the direction of travel  shall be the same as when the scale is in 
normal use.  The minimum in -motion test shall be three reference weight cars passed over the scale three times.  The 
cars shall be selected to cover the range of weights that are normally weighed on the system and  to reflect the types of 
cars normally weighed.  
(Added 1993)  2.20. Scales   Handbook 44 –  20152016  
Markup Copy 
Agency No. 209.02  
  
N.6. Nominal Capacity of Prescription Scales.  – The nominal capacity  of a prescription  scale shall be assumed 
to be one -half apothecary ounce, unless otherwise marked.  (Applicable only to scales not marked with an accuracy  
class .) 
 
T. Tolerances Applicable to Devices not  Marked  I, II, III, III L, or  IIII  
 
T.1. Tolerance Values.  
 
T.1.1.  General.  – The tolerances  applicable to devices not marked with an accuracy  class  shall have the 
tolerances applied as specified in Table T.1.1. Tolerances for Unmarked Scales.  
(Amended 1990)  
 
T.1.2.  Postal and Parcel Post Scales.  – The tolerances  for postal and parcel post scales  are given in 
Table  T.1.1. Tolerances for Unmarked Scales and Table 5. Maintenance and Acceptance Tolerances for 
Unmarked Postal and Parcel Post Scales.  
(Amended 1990)Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 (Table Added 1990; Amended 1992, 1993, and 2012)  
 Table T.1.1. Tolerances for Unmarked Scales  
Type of Device Subcategory  Minimum 
Tolerance Acceptance  
Tolerance Maintenance 
Tolerance Decreasing -
Load  
Multiplier1 Other Applicable 
Requirements  
Vehicle, axle- load, livestock, 
railway track (weighing statically), crane, and hopper (other than grain hopper)   Class  III L, T.N.3.1 (Table  6) and T.N.3.2.  1.0 T.N.2., T.N.3., T.N.4.1., 
T.N.4.2., T.N.4.3., 
T.N.4.4., T.N.5., 
T.N.7.2., T.N.8.1.4.4, 
T.N.9.  
Grain test scales  n ≤ 10 000 
n > 10  000 Class  III, T.N.3.1. (Table  6) and T.N.3.2.  
Class  II, T.N.3.1. (Table  6) and T.N.3.2.  1.0 T.N.8.1.4.4, T.N.9. 
Railway track scales  
weighing in motion   T.N.3.6. except that for T.N.3.6.2.  (a), no 
single error shall exceed four times the 
maintenance  tolerance.  1.0 T.N.8.1.4.4, T.N.9. 
Monorail scales , in-motion   T.N.3.8.  1.0 T.N.8.1.4.4, T.N.9.  
Customer -operated 
bulk-weighing systems for 
recycled materials   ± 5 % of applied material test  load.  
Average error on 10 or more test loads  ≤ 
2.5 %. 1.0 T.N.8.1.4.4, T.N.9. 
Wheel -load weighers and 
portable axle- load scales  Tested 
individually or 
in pairs2 0.5 d or 50 
lb, 
whichever is 
greater  1 % of test 
load 2 % of test load  1.53 T.N.8.1.4.4, T.N.9. 
Prescription  scales   0.1 grain (6 
mg) 0.1 % of test 
load 0.1 % of test 
load 1.5 T.N.8.1.4.4, T.N.9. 
Jewelers’ scales  Graduated  0.5 d 
0.05 % of test 
load 0.05 % of test 
load 1.5  
 Ungraduated  Sensitivity 
or smallest 
weight, 
whichever is 
less  T.N.8.1.4.4, T.N.9. 
Dairy -product test  scale  Loads < 18 g  
18 g load  0.2 grain  
0.2 grain  0.2 grain  
0.3 grain  0.2 grain  
0.5 grain  1.5 T.N.8.1.4.4, T.N.9. 
Postal  and parcel post scales  
designed/used to weigh  
loads <  2 lb Loads < 2 lb 15 grain, 
1 g, 1/32 oz, 
0.03 oz, or 
0.002  lb 15 grain, 1  g, 
1/32 oz, 
0.03 oz, or 
0.002  lb 15 grain, 1  g, 
1/32 oz, 0.03 oz, 
or 0.002 lb 1.5 T.N.8.1.4.4, T.N.9. 
 Loads ≤ 2 lb Table 5  Table 5  Table 5    
Other postal  and parcel post 
scales   Table 5  Table 5  Table 5  1.5 T.N.8.1.4.4, T.N.9. 
All other scales (including grain hopper)  n > 5000  0.5 d or 
0.05 % of 
scale 
capacity,  
whichever is 
less 0.05 % of test 
load 0.1 % of test 
load 1.5 T.N.2.5., T.N.4.1., T.N.4.2., T.N.4.3., 
T.N.5., T.N.7.2.,   
T.N.8.1.4.
4, T.N.9. 
n ≤ 5000  Class III, T.N.3.1., Table  6 and T.N.3.2. 1.0 T.N.2., T.N.3., T.N.4.1., 
T.N.4.2., T.N.4.3., 
T.N.5., T.N.7.2., 
T.N.8.1.4.4, T.N.9. 
1 The decreasing load test  applies only to automatic indicating 
scales . 
2 If marked and tested as a pair, the tolerance shall be applied to 
the sum of the indication.  3 The decreasing load test  does not apply to portable wheel load 
weighers.  
4 T.N.8.1.4. Operating Temperature. is nonretroactive and 
effective for unmarked devices manufactured as of 
January  1, 1981.                                                                                                                                          
  
 
 
T.2. Sensitivity Requirement (SR).  
 
T.2.1.  Application.  – The sensitivity requirement  (SR) is applicable to all nonautomatic -indicating 
scales not marked I , II, III, III L, or IIII, and is the same whether acceptance or maintenance  tolerances  apply.  
 
T.2.2.  General.  – Except for scales specified in paragraphs  T.2.3. Prescription Scales through T.2.8. 
Railway Track Scales:  2  d, 0.2 % of the scale capacity , or 40  lb, whichever is least.  
 
T.2.3.  Prescription Scales.   6 mg (0.1  grain).  
 T.2.4.  Jewelers’ Scales.  
 
T.2.4.1.  With One -Half Ounce Capacity or Less.  – 6  mg (0.1  grain).  
 
T.2.4.2.  With More Than One -Half Ounce Capacity.  – 1 d or 0.05 % of the scale capacity , whichever 
is less.  
 
T.2.5.  Dairy -Product Test Scales.  
 
T.2.5.1.  Used in Determining Butterfat Content.  – 32 mg (0.5  grain).  
 
T.2.5.2.  Used in Determining Moisture Content.  – 19 mg (0.3  grain).  
 
T.2.6.  Grain Test Scales.  – The sensitivity shall be as stated in T.N.6. Sensitivity.  
(Amended 1987)  
 
T.2.7.  Vehicle, Axle -Load, Livestock, and Animal Scales.  
 
T.2.7.1.  Equipped With Balance Indicators.  – 1 d. 
 
T.2.7.2.  Not Equipped With Balance Indicators.  – 2 d or 0.2 % of the scale capacity , whichever is 
less. Table 5.  
Maintenance and Acceptance Tolerances for Unmarked  
Postal and Parcel Post Scales  
Scale Capacity  Test Loads  Maintenance Tolerance  
(±) Acceptance Tolerance  
(±) 
(lb) (lb) (oz) (lb) (oz) (lb) 
0 to 4, inclusive*  0 to 1, inclusive  1/32 0.002  1/32 0.002  
 over 1  1/8 0.008  1/16 0.004  
over 4*  0 to 7, inclusive  3/16 0.012  3/16 0.012  
 7+ to 24, inclusive  3/8 0.024  3/16 0.012  
 24+ to 30, inclusive  ½ 0.030  ¼ 0.015  
 over 30  0.1 % of Test Load  0.05 % of Test Load  
*Also see Table  T.1.1. Tolerances for Unmarked Scales for scales designed and/or used to weigh loads less than 
2 lb. Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
  
T.2.8.  Railway Track Scales.  – 3 d or 100 lb, whichever is less.  
 
T.3. Sensitivity Requirement, Equilibrium Change Required.  
 
The minimum change in equilibrium with test loads  equal to the values specified in T.2. Sensitivity Requirements 
(SR) shall be as follows:  
 
(a) Scale with a Trig Loop but without a Balance Indicator.  – The position of rest of the weighbeam shall 
change from the center of the trig loop to the top or bottom, as the case may be.  
 
(b) Scale with a Single Balance Indicator and Having a Nominal Capacity of Less Than 250  kg (500 lb).  
– The position of rest of the indicator  shall change 1.0  mm (0.04  in) or one division on the graduated scale, 
whichever is greater.  
 
(c) Scale with a Single Balance Indicator and Having a Nominal Capacity of 250 kg (500 lb) or Greater.   
– The position of rest of the indicator  shall change 6.4  mm (0.25  in) or one division on the graduated scale 
or the width of th e central target area, whichever is greater.  However, the indicator on a batching scale 
shall change 3.2  mm (0.125 in) or one division on the graduated scale, whichever is greater.  
 (d) Scale with Two  Opposite -Moving Balance Indicators.  – The position of rest of the two indicators 
moving in opposite directions shall change 1.0  mm (0.04  in) with respect to each other.  
 
(e) Scale with Neither a Trig Loop nor a Balance Indicator.  – The position of rest of the weighbeam or 
lever system shall change from the horizontal, or midway between limiting stops, to either limit of motion.  
 
 
T.N.  Tolerances Applicable to Devices Marked  I, II, III, III L, and  IIII.  
 
T.N.1. Principles.  
 
T.N.1.1.  Design.  – The tolerance for a weighing device is a performance requirement independent of the 
design principle used.  
 
T.N.1.2.  Accuracy Classes.  – Weighing devices are divided into accuracy  classes  according to the number of 
scale divisions  (n) and the value of the scale division  (d). 
 
T.N.1.3.  Scale Division.  – The tolerance for a weighing device is related to th e value of the scale division  (d) 
or the value of the verification scale division  (e) and is generally expressed in terms of d or e.  
 
T.N.2. Tolerance Application.  
 
T.N.2.1.  General.  – The tolerance values are positive (+) and negative (−) with the weighing device adjusted 
to zero at no load.  When tare  is in use, the tolerance values are applied from the tare zero reference (zero net 
weight indication); the tolerance values  apply to the net weight indication for any possible tare load using 
certified test loads . 
(Amended 2008)  
 
T.N.2.2.  Type Evaluation Examinations.  – For type evaluation  examinations, the tolerance values apply to 
increas ing and decreasing load tests  within the temperature , power supply, and barometric pressure  limits 
specified in  T.N.8. 
 
T.N.2.3.  Subsequent Verification Examinations.  – For subsequent verification  examinations, the tolerance 
values apply regardless of the influence factors  in effect at the time of the conduct of the examination.  (Also 
see G -N.2. Testing with Nonassoc iated Equipment.)   
  
T.N.2.4.  Multi -Interval and Multiple Range (Variable Division -Value) Scales.  – For multi -interval  and 
multiple range scales, the tolerance values are based on the value of the scale division of the range in use.  
 T.N.2.5.  Ratio Tests.  – For ratio tests , the tolerance values are 0.75 of the applicable tolerances . 
 
T.N.3. Tolerance Values.  
 
T.N.3.1.  Maintenance Tolerance Values.  – The maintenance  tolera nce values are as specified in Table 6. 
Maintenance Tolerances.  
 
T.N.3.2.  Acceptance Tolerance Values.  – The acceptance tolerance values shall be one -half the ma intenance  
tolerance values.  
 T.N.3.3.  Wheel -Load Weighers and Portable Axle -Load Weighers of Class  IIII. – The tolerance values 
are two times the values specified in T.N.3.1. Maintenance Tolerance Values and T.N.3.2. Acceptance 
Tolerance Values.  
(Amended 1986)  
 
T.N.3.4.  Crane and Hopper (Other than Grain Hopper) Scales.  – The maintenance  and acceptance  
tolerances  shall be as specified in T.N.3.1. Maintenance Tolerance Values and T.N.3.2. Acceptance Tolerance 
Values for Class III L, except that the tolerance for crane and construction materials hopper scales  shall not be 
less than 1  d or 0.1  % of the scale capacity , whichever is less.  
(Amended 1986)  
 
Table 6.  
Maintenance Tol erances  
(All values in this table are in scale divisions)  
Tolerance in Scale Divisions  
 1 2 3 5 
Class  Test Load  
 I       0 - 50 000 50 001 - 200 000 200 001 +   
 II       0 -   5 000 5 001 - 20 000 20 001 +   
 III       0 -      500 501 - 2 000  2 001 - 4 000 4 001 + 
 IIII       0 -        50 51 - 200 201 - 400 401 + 
 III L    0 -      500 501 - 1 000 (Add 1 d for each  additional 500  d or fraction thereof)  
 
T.N.3.5.  Separate Main Elements:  Load Transmitting Element, Indicating Element, Etc.  – If a main 
element separate from a complete weighing device is submitted for laboratory type evaluation , the tolerance for 
the main  element is 0.7 that for the complete weighing device.  This fraction includes the tolerance attributable 
to the testing devices used.  
(Amended 2015)  
 
T.N.3.6.  Coupled- In-Motion Railroad Weighing Systems.  – The maintenance  and acceptance  tolerance 
values for the group of weight values appropriate to the application must satisfy the f ollowing conditions:  
(Amended 1990 and 1992)  
 
T.N.3.6.1. – For any group of weight values, the difference in the sum of the individual in- motion car 
weights of the group as compared to the sum of the individual static weights shall not exceed  0.2 %. 
(Amend ed 1990)  
 Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 T.N.3.6.2.  – If a weighing system is used to weigh trains of five or more cars, and if the individual car 
weights are used, any single weight value within the group must meet the following criteria:  
 
(a) no single error may exceed three times the static maintenance  tolerance;  
 
(b) not more than 5  % of the errors may exceed two times the static maintenance tolerance ; and  
 
(c) not more than 35  % of the errors may  exceed the static maintenance tolerance.  
(Amended 1990 and 1992)  
 
T.N.3.6.3. – For any group of weight values wherein the sole purpose is to determine the sum of the group, 
T.N.3.6.1. alone applies.  
(Amended 1990)  
 T.N.3.6.4. – For a weighing system used to weigh trains of less than five cars, no single car weight within 
the group may exceed the static maintenance tolerance.  
(Amended 1990 and 1992)  
 
T.N.3.7.  Uncoupled- in-Motion Railroad Weighing Systems.  – The maintenance  and acceptance tolerance  
values for any single weighment within a group of non -interactive (i.e., uncoupled) loads, the weighment er ror 
shall not exceed the static maintenance tolerance.  
(Amended 1992)  
 T.N.3.8.  Dynamic Monorail Weighing System.  – Acceptance tolerance shall be the same as the 
maintenance  tolerance  shown in Table  6. Maintenance Tolerances.  On a dynamic test of twenty or more 
individual test loads , 10 % of the individual test loads may be in error, each not to exceed two times the 
tolerance.  The error on t he total of the individual test loads shall not exceed ±  0.2 %.  (Also see Note in 
N.1.3.5.1. Dynamic Monorail Weighing Systems.)  For equipment undergoing type evaluation, a tolerance equal to one -half the maintenance tolerance values  shown in Table  6. Maintenance Tolerances shall apply.  
[Nonretroactive January  1, 2002]  
(Added 1986) (Amended 1999 and 2001)  
 T.N.3.9.  Materials Test on Customer -Operated Bulk Weighing Systems for Recycled Materials.  – The 
maintenance  and acceptance tolerance shall be ±  5 % of the applied materials test load except that the average 
error on ten or more test materials test loads  shall not exceed ±  2.5 %. 
(Added 1986)  
 
T.N.3.10.  Prescription Scales with a Counting Feature.  – In addition to Table  6. Maintenance Tolerances 
(for weight), the indicated piece count value computed by a Class  I or Class II prescription  scale counting 
feature shall comply with the tolerances in Table T.N.3.10. Maintenance and Acceptance Tolerances in Excess 
and in Deficiency for Count.  
 
Table T.N.3.10.  
Maintenance and Acceptance Tolerances  
in Excess and in Deficiency  for Count  
Indication of Count  Tolerance  
(piece  count)  
0 to 100  0  
101 to 200  1  
201 or more         0.5 % 
(Added 2003)  
  
 T.N.3.11.  Tolerances for Substitution Test.  – Tolerances are applied to the scale based on the substitution 
test load.  
(Added 2003)  
 
T.N.3.12.  Tolerances for Strain -Load Test.  – Tolerances apply only to the test weights or substitution  test 
loads.  
(Added 2003)  
 
T.N.4. Agreement of Indications.  
 
T.N.4.1.  Multiple Indicating/Recording Elements.  – In the case of a scale or weighing system equipped 
with more than one indicating element  or indicating element and recording element combination, where the 
indicators  or indicator/ recorder combination are intended to be used independently of one another, tolerances  
shall be applied independently to each indicator or indicator/recorder combination.  
(Amended 1986)  
 
T.N.4.2.  Single Indicating/Recording Element.  – In the case of a scale or weighing system with a single 
indicating element  or an indicating/recording element combination, and equipped with component parts such as 
unit weights , wei ghbeam and weights, or multiple weighbeams that can be used in combination to indicate a 
weight, the difference in the weight value indications of any load shall not be greater than the absolute value of 
the applicable tolerance for that load, and shall be within tolerance limits.  
(Amended 1986)  
 
T.N.4.3.  Single Indicating Element/Multiple Indications.  – In the case of an analog indicating element  
equipped with two or more indicating means within the same element, the difference in t he weight indications 
for any load other than zero shall not be greater than one- half the value of the scale division  (d) and be within 
tolerance limits.  
(Amended 1986)  
 
T.N.4.4.  Shift or Section Tests.  – The range of the results obtained during the conduc t of a shift test or a 
section test shall not exceed the absolute value of the maintenance tolerance  applicable and each test result shall 
be within applicable tolerances . 
(Added 1986)  
 
T.N.4.5.  Time Dependence.  – A time dependence test shall be conducted during type evaluation  and may be 
conducted during field verification, provided test conditions remain constant.  
(Amended 1989 and 2005)  
 
T.N.4.5.1.  Time Dependence:  Class  II, III, and  IIII Non -automatic Weighing Instruments.  – A 
non-automatic weighing instrument of Classes  II, III, and  IIII shall meet the following requirements at 
constant test conditions.  During type evaluation, this test shall be conducted at 20  °C ± 2 °C (68  °F ± 4 °F): 
 
(a) When any load is kept on an instrument, the difference between the indication obtained 
immediately after placing the load and the indication observed during the following 30 minutes 
shall not exceed 0.5  e.  However, the difference between the indication obtained at 15  minutes and 
the indication obtained at 30  minutes shall not exceed 0.2  e. 
 
(b) If the conditions in (a) are no t met, the difference between the indication obtained immediately 
after placing the load on the instrument and the indication observed during the following 
4four hours shall not exceed the absolute value of the maximum permissible error at the load 
applied.  
 (Added 2005) (Amended 2006 and 2010)  
 Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 T.N.4.5.2.  Time Dependence: Class  III L Non -automatic Weighing Instruments.  – A non -
automatic weighing instrument of Class  III L shall meet the following requirements:  
 
(a) When any load is kept on an instrument, the difference between the indication obtained 
immediately after placing the load and the indication observed during the following 30 minutes 
shall not exceed  1.5 e.  However, the difference between the indication o btained at 15  minutes and 
the indication obtained at 30  minutes shall not exceed 0.6  e. 
 
(b) If the conditions in (a) are not met, the difference between the indication obtained immediately 
after placing the load on the instrument and the indication observ ed during the following 
4four hours shall not exceed the absolute value of the maximum permissible error at the load 
applied.  
 (Added 2005) (Amended 2010)  
 
T.N.4.5.3. Zero Load Return: Non -automatic Weighing Instruments.  – A non -automatic weighing 
instrument shall meet the following requirements at constant test conditions.  During type evaluation, this 
test shall be conducted at 20  °C ± 2 °C (68  °F ± 4 °F).  The deviation on re turning to zero as soon as the 
indication has stabilized, after the removal of any load which has remained on the instrument for 
30 minutes shall not exceed:  
 
(a)  0.5  e for Class II and IIII devices,  
 (b)  0.5  e for Class III devices with 4000 or fewer di visions,  
 (c)  0.83 e for Class III devices with more than 4000 divisions, or  
 
(d)  one -half of the absolute value of the applicable tolerance for the applied load for Class  III L 
devices.  
 
For a multi -interval instrument, the deviation shall not exceed 0. 83 e
1 (where e 1 is the interval of the first 
weighing segment of the scale).  
 
On a multiple range instrument, the deviation on returning to zero from Max i (load in the applicable 
weighing range) shall not exceed 0.83 ei (interval of the weighing range).  Furthermore, after returning to 
zero from any load greater than Max 1 (capacity of the first weighing range) and immediately after 
switching to the lowest weighing range, the indication near zero shall not vary by more th an e 1 (interval of 
the first weighing range) during the following five  minutes.  
(Added 2010)  
 
T.N.4.6.  Time Dependence (Creep) for Load Cells during Type Evaluation.  – A load cell (force 
transducer) marked with an accuracy class shall meet the following requirements at constant test conditions:  
 
(a) Permissible Variations of Readings . – With a constant maximum load for the measuring range 
(Dmax) between 90  % and 100 % of maximum capacity (E max), applied to the load cell, the 
difference between the initial reading and any reading obtained during the next 30  minutes shall 
not exceed the absolute value of the maximum permissible error (mpe)  for the applied load. (Also 
see Table T.N.4.6. Maximum Permissible Error (mpe) for Load Cells During Type Evaluation.)  
The difference between the reading obtained at 20  minutes and the reading obtained at 30  minutes 
shall not exceed 0.15  times the abs olute value of the mpe.  (Also see Table T.N.4.6. Maximum 
Permissible Error (mpe) for Load Cells During Type Evaluation) 
  
 (b) Apportionment Factors.  – The mpe for creep  shall be determ ined from Table  T.N.4.6. Maximum 
Permissible Error (mpe) for Load Cells  During Type Evaluation using the following 
apportionment factors (p LC): 
 
pLC = 0.7 for load cells  marked with S (single load cell applications),  
pLC = 1.0 for load cells marked with M (multiple load cell applications), and  
pLC = 0.5 for Class  III L load cells marked with S or M.  
 (Added 2005, Amended 2006)  
 
Table T.N.4.6. 
Maximum Permissible Error (mpe) * for Load Cells During Type Evaluation  
mpe in Load Cell Verifications Divisions (v) =  pLC x Basic Tolerance in v  
Class  pLC x 0.5 v  pLC x 1.0 v  pLC x 1.5 v  
 I       0 -  50 000 
v 50 001 v -  200 000 
v 200 001 v +  
 II       0 -    5 000 
v 5 001 v -  20 000 v  20 001 v +  
 III       0 -       500 
v 501 v -  2 000 v  2 001 v +  
 IIII       0 -         50 
v 51 v -  200 v  201 v +  
 III L       0 -       500 
v 501 v -  1 000 v  (Add 0.5 v to the basic tolerance for each additional 500 
v or fraction thereof up to a maximum load of 10  000 v)  
v represents the load cell verification interval  
pLC represents the apportionment factor s applied to the basic tolerance 
pLC = 0.7 for load cells marked with S (single load cell applications)  
pLC = 1.0 for load cells marked with M (multiple load cell applications)  
pLC = 0.5 for Class  III L load cells marked with S or  M 
* mpe  = p LC x× Basic Tolerance in load cell verifications divisions (v)  
(Table Added 2005) (Amended 2006)  
 
T.N.4.7.  Creep Recovery for Load Cells During Type Evaluation.  – The difference between the initial 
reading of the minimum load of the measuring range (D min) and the reading after returning to minimum load 
subsequent to the maximum load (D max) having been applied for 30 minutes shall not exceed:  
 
(a) 0.5 times the value of the load cell verification interval (0.5  v) for Class   II and  IIII load cells;  
 
(b) 0.5 times the value of the load cell verification interval (0.5  v) for Class  III load cells with 4000 or 
fewer divisions;  
 
(c) 0.83 times the value of the  load cell verification interval (0.83  v) for Class  III load cells with more than 
4000 divisions; or  
 
(d) 2.5 times the value of the load cell verification interval (2.5  v) for Class  III L load cells.  
(Added 2006) (Amended 2009 and 2011)  
 
T.N.5. Repeatability.  – The results obtained from several weighings of the same load under reasonably static test 
conditions shall agree within the absolute value of the maintenance  tolerance for that load, and sha ll be within 
applicable tolerances . 
 Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 T.N.6. Sensitivity.  – This section is applicable to all nonautomatic -indicating scales marked I , II, III, III L, or IIII.  
 
T.N.6.1.  Test Load.  
 
(a) The test load for sensitivity for nonautomatic -indicating vehicle , axle -load, livestock , and animal 
scales shall be 1  d for scales equipped with balance indicator , and 2  d or 0.2 % of the scale capacity , 
whichever is less, for scales not equipped with balance indicators.  
 
(b) For all other nonautomatic -indicating scales, the test load for sensitivity shall be 1  d at zero and 2  d at 
maximum test load.  
 
T.N.6.2.  Minimum Change of Indications.  – The addition or removal of the test load for sensitivity shall 
cause a minimum permanent change as follows:  
 
(a) for a scale with trig loop but without a balance indicator , the position of the weighbeam shall change 
from the center to the outer limit of the trig loop; 
 
(b) for a scale with balance indicator , the position of the indicator  shall change one divis ion on the 
graduated scale, the width of the central target area, or the applicable value as shown below, whichever 
is greater:  
 
Scale of Class  I or II:  1  mm (0.04 in), 
Scale of Class  III or IIII with a maximum capacity  of 30 kg (70 lb) or less:  2  mm (0.08 in), 
Scale of Class  III, III L, or IIII with a maximum capacity  of more than 30 kg (70  lb):  5  mm (0.20 in); 
 
(c) for a scale without a trig loop or balance indicator , the position of rest of the weighbeam or lever 
system shall change from the horizontal or midway between limiting  stops to either limit of motion.  
(Amended 1987)  
 
T.N.7. Discrimination.  
 
T.N.7.1.  Analog Automatic Indicating (i.e., Weighing Device with Dial, Drum, Fan, etc.).  – A test load 
equivalent to 1.4  d shall cause a change in the indication of at least 1.0  d.  (Also see N.1.5. Discrimination Test.)  
 
T.N.7.2.  Digital Automatic Indicating.  – A test load equivalent to 1.4  d shall cause a change in the indicated 
or recorded  value of at least 2.0  d.  This requires the zone of uncertainty to be not greater than three -tenths of 
the value of the scale division.  (Also see N.1.5.1. Digital Device.)  
 
T.N.8. Influence Factors.  – The following factors are appl icable to tests conducted under controlled conditions 
only, provided that:  
 
(a) types of devices approved prior to January  1, 1986, and manufactured prior to January  1, 1988, need not 
meet the requirements of this section;  
 
(b) new types of devices submitt ed for approval after January  1, 1986, shall comply with the requirements of 
this section; and  
 
(c) all devices manufactured after January  1, 1988, shall comply with the requirements of this section.  
(Amended 1985)  
 
T.N.8.1.  Temperature.  – Devices shall satisfy the tolerance requirements under the following temperature  
conditions:  
  
 T.N.8.1.1.  If not specified in the operating instructions for Class  I or II scales, or if not marked on 
the device for Class  III, III L, or IIII scales, the temperature limits shall be:  −  10 °C to 40  °C (14  °F to 
104 °F). 
 
T.N.8.1.2.  If temperature  limits are specified for the device, the range shall be at least that specified 
in Table  T.N.8.1.2. Temperature Range by Class.  
 
Table T.N.8.1.2. 
Temperature Range by Class  
Class  Temperature Range  
I 5 ºC (9  °F) 
II 15 ºC (27  °F) 
III, III L, and IIII  30 ºC (54  °F) 
 
T.N.8.1.3.  Temperature Effect on Zero -Load Balance.  – The zero -load indication shall not vary 
by more than:  
 
(a) three divisions per 5  °C (9 °F) change in temperature for Class III L devices; or  
 
(b) one division per 5  °C (9 °F) change in temperature for all other devices.  
(Amended 1990)  
 
T.N.8.1.4.  Operating Temperature.  – Except for Class  I and II devices, an indicating or recording 
element shall not display nor record any usable values until th e operating temperature necessary for 
accurate weighing and a stable zero balance condition  have been attained.  
 
T.N.8.2.  Barometric Pressure.  – Except for Class  I scales, the zero indication  shall not vary by more than 
one scale division for a change in barometric pressure of 1 kPa over the total barometric pressure range of 
95 kPa to 105 kPa (28  in to 31  in of Hg).  
 
T.N.8.3.  Electric Power Supply.  
 
T.N.8.3.1.  Power Supply, Voltage and Frequency.  
 
(a) Weighing devices that operate using alternating current must perform within the conditions 
defined in paragraphs  T.N.3. Tolerance Values through T. N.7. Discrimination, inclusive, when 
tested over the range of −  15 % to +  10 % of the marked nominal line voltage(s) at 60  Hz, or the 
voltage range marked by the manufacturer, at 60  Hz. 
(Amended 2003)  
 
(b) Battery operated instruments shall not indicate no r record values outside the applicable tolerance 
limits when battery power output is excessive or deficient.  
 
T.N.8.3.2.  Power Interruption.  – A power interruption  shall not cause an indicating or recording 
element to display or record any values outside the applicable tolerance limits.  
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 T.N.9. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility.  – The 
difference between  the weight indication due to the disturbance and the weight indication without the disturbance 
shall not exceed one scale division  (d); or the equipment shall: 
 
(a) blank the indication; or  
 
(b) provide an error message; or  
 (c) the indication shall be so  completely unstable that it cannot be interpreted, or transmitted into memory or to 
a recording element, as a correct measurement value.  
 
The tolerance in T.N.9. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility is 
to be applied independently of other tolerances .  For example, if indications are at allowable basic tolerance error 
limits when the disturbance occurs, then it is acceptable for the indication to exceed the applicable basic tolerances 
durin g the disturbance.   
(Amended 1997)  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  – Equipment shall be suitable for the service in which it is used with respect to 
elements of its design, including but not limited to, its capacity , number of scale divisions, value of the scale 
division or verification scale division, minimum capacity, and computing capability.30 
 
UR.1.1.  General.  
 
(a) For devices marked with a class designation, the typical class or type of device for particular weighing 
applications is shown in Table  7a. Typical Class or Type of Device for Weighing Applications.  
 
(b) For devices not marked with a class designation, Table 7b. Applicable to Devices not Marked with a 
Class Designation applies.  
 
                                                           
30 Purchasers and users of scales such as railway track, hopper, and vehicle scales  should be aware of possible 
additional requirements for the design and installation of such devices.  
(Footnote Added 1995)  
  
 Table 7a.  
Typical Class  or Type of Device for Weighing Applications  
Class  Weighing Application or Scale Type  
I Precision laboratory weighing  
II Laboratory weighing, precious metals and gem weighing, grain test scales  
III All commercial weighing not otherwise specified, grain test scales, retail precious metals and semi -
precious gem weighing, grain -hopper scales, animal scales, postal scales , vehicle on-board weighing 
systems with a capacity less than or equal to 30  000 lb, and scales used to determine laundry charges  
III L Vehicle scales , vehicle on -board weighin g systems with a capacity greater  than 30  000 lb, axle -load 
scales , livestock scales , railway track scales,  crane scales, and hopper (other than grain hopper) scales  
IIII Wheel -load weighers and portable axle -load weighers  used for highway weight enforcement  
Note :  A scale with a higher accuracy  class  than that specified as “typical” may be used.  
 (Amended 1985, 1986, 1987, 1988, 1992, 1995, and 2012)  
 
Table 7b.  
Applicable to Devices not Marked with a Class  Designation  
Scale Type or Design  Maximum Value of d  
Retail Food Scales, 50  lb capacity  and less  1 oz 
Animal Scales  1 lb 
Grain Hopper Scales  
 Capacity up to and including 50 000 lb 
 Capacity over 50  000 lb  
10 lb (not greater than 0.05  % of capacity)  
20 lb 
Crane Scales  not greater than 0.2  % of capacity  
Vehicle and Axle -Load Scales  Used in Combination  
 Capacity up to and including 200 000 lb 
 Capacity over 200  000 lb  
20 lb 
50 lb 
Railway Track Scales  
 With weighbeam  
 Automatic indicating   
20 lb 
100 lb 
Scales with capacities greater than 500  lb except 
otherwise specified  0.1 % capacity (but not greater than 50  lb) 
Wheel -Load Weighers  0.25 % capacity (but not greater than 50  lb) 
Note :  For scales not specified in this table, G -UR.1.1. and UR.1. apply.  
(Added 1985) (Amended 1989)  
 
UR.1.2.  Grain Hopper Scales.  –  Hopper scales manufactured as of January 1, 1986, that are used to weigh 
grain shall be Class III and have a minimum of 2000 scale divisions.  
(Amended 2012)  
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  Agency No. 209.02  
 UR.1.3. Value of the Indicated and Recorded Scale Division.  – The value of the scale division as recorded 
shall be the same as the division value indicated.  
[Nonretroactive as of January  1, 1986]  
(Added 1985) (Amended 1999)  
 
UR.1.3.1.  Exceptions.  – The provisions of UR.1.3. Value of the Indicated and Recorded Scale 
Division shall not apply to: 
 
(a) Class  I scales, or  
 
(b) Dynamic monorail weighing systems when the value of d is less than the value of  e. 
(Added 1999)  
 
UR.1.4.  Grain -Test Scales:  Value of the Scale Divisions.  – The scale division for grain -test scales shall not 
exceed 0.2  g for loads through 500 g, and shall not exceed 1  g for loads above 500 g through 1000 g. 
(Added 1992)  
 UR.1.5. Recording Element, Class  III L Railway Track Scales.  – Class III L Railway Track Scales must be 
equipped with a recording element.  
[Nonretroactive as of January  1, 1996]  
(Added 1995)  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Supports.  – A scale that is portable and that is being used on a counter, table, or the floor shall be so 
positioned that it is firmly and securely supported.  
 
UR.2.2.  Suspension of Hanging Scale.  – A hanging scale  shall be freely suspended from  a fixed support 
when in use.  
 
UR.2.3.  Protection From Environmental Factors.  – The indicating elements,  the lever system or load cells,  
and the load -receiving element of a permanently installed scale, and the indicating elements of a scale not 
intended to be permanently installed, shall be adequately protected from environmental factors  such as wind, 
weather, an d RFI  that may adversely affect the operation or performance of the device.  
 
UR.2.4.  Foundation, Supports, and Clearance.  – The foundation and supports  of any scale installed in a 
fixed location shall be such as to pr ovide strength, rigidity, and permanence of all components, and clearance  
shall be provided around all live parts to the extent that no contacts may result when the load -receiving element 
is empty, nor throughout the weighing range of the sc ale.  An in -motion railway track scale is not required to 
provide clearance using rail gaps to separate the live rail portion of the weighing/load -receiving element from 
that which is not live if the scale is designed to be installed and operated using con tinuous rail.  On vehicle and 
livestock scales,  the clearance between the load -receiving elements and the coping at the bottom edge of the  
platform shall be greater than at the top edge of the platform.* 
[*Nonretroactive as of January  1, 1973]  
(Amended 2014)  
 UR.2.5.  Access to Weighing Elements.  – Adequate provision shall be made for ready access to the pit of a 
vehicle, livestock, animal, axle -load, or railway track scale for the purpose of inspection and maintenance .  Any 
of these scales without a pit shall be installed with adequate means for inspection and maintenance of the weighing elements . 
(Amended 1985)  
  
 UR.2.6.  Approaches.  
 
UR.2.6.1.  Vehicle Scales.  – On the entrance and exit end(s) of a vehicle scale, there shall be a 
straight approach as follows:  
 
(a) the width at least the width of the platform,  
 
(b) the length at least one -half the length of the platform but not required to be  more than 12 m 
(40 ft), and  
 (c) not less than 3 m (10  ft) of any approach adjacent to the platform shall be in the same plane as the 
platform.  Any slope in the remaining portion of the approach shall ensure (1)  ease of vehicle 
access, (2)  ease for testi ng purposes, and (3)  drainage away from the scale.  
 In addition to (a), (b), and (c),  scales installed in any one location for a period of six months or more shall 
have not less than 3 m (10 ft) of any approach adjacent to the platform constructed of concr ete or similar 
durable material to ensure that this portion remains smooth and level  and in the same plane as the 
platform; however, grating of sufficient strength to withstand all loads equal to the concentrated load 
capacity  of the scale may be installed in this portion.  
[Nonretroactive as of January  1, 1976]  
(Amended 1977, 1983, 1993, 2006, and 2010)  
 
UR.2.6.2.  Axle -Load Scales.  – At each end of an axle -load scale there shall be a straight paved 
approach in the same plane as the platform.  The approaches  shall be the same width as the platform and of 
sufficient length to insure the level  positioning of vehicles during weight determinations.  
 
UR.2.7.  Stock Racks.  – A livestock or animal scale shall be equipped with a suitable stock rack, with gates 
as required, which shall be securely mounted on the scale platform.  Adequate clearances shall be maintained 
around the outside of the rack.  
 
UR.2.8.  Hoists.  – On vehicle scales  equipped with means for raising the load- receiving element from the 
weighing element for vehicle unloading, means shall be provided so that it is readily apparent to the scale 
operator when the load -receiving element i s in its designed weighing position.  
 
UR.2.9. Provision for Testing Dynamic Monorail Weighing Systems . – Provisions shall be made at the time 
of installation of a dynamic monorail weighing systems for testing in accordance with N.1.3.5.1. Dynamic Monorail Weighing Systems (a rail around or other means for returning the test carcasses to the scale being 
tested).  
[Nonretroactive as of January  1, 1998]  
(Added 1997) (Amended 1999)  
 
UR.3.  Use Requirements.  
 
UR.3.1.  Recommended Minimum Load.  – A recommended minimum load is specified in Table  8 since the 
use of a device to weigh light loads is likely to result in relatively large errors.  
 Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 Table 8.  
Recommended Minimum Load 
Class  Value of Scale Division  
(d or e*)  Recommended Minimum Load  
(d or e*)  
I equal to or greater than 0.001  g 100 
II 0.001  g to 0.05  g, inclusive  20 
 equal to or greater than 0.1  g 50 
III    All**  20 
   III L All 50 
IIII All 10 
*For Class  I and II devices equipped with auxiliary reading means (i.e., a rider, a vernier, or a least 
significant decimal differentiated by size, shape or color), the value of the verification scale division “e” 
is the value of the scale division immediately preceding the auxiliary means.  For Class  III and IIII 
devices the value of “e” is specified by the manufacturer as marked on the device; “e” must be less than or equal to “d.”  
 
**A minimum load  of 10 d is recommended for a weight classifier  marked in accordance with a 
statement identifying its use for special applications.  
(Amended 1990)  
 
UR.3.1.1.  Minimum Load, Grain Dockage Determination.  – When deter mining the quantity of 
foreign material (dockage) in grain, the weight of the sample shall be equal to or greater than 500  scale 
divisions.  
(Added 1985)  
 
UR.3.2.  Maximum Load.  – A scale shall not be used to weigh a load of more than the nominal capacity  of 
the scale.  
 
UR.3.2.1.  Maximum Loading for Vehicle Scales.  – A vehicle scale shall not be used to weigh 
loads exceeding the maximum load capacity  of its span as specified in Table  UR.3.2.1. Span Maximum 
Load.  
(Added 1996)  
 
Table UR.3.2.1.  
Span Maximum Load  
Distance in Feet 
Between the 
Extremes of any 
Two or More 
Consecutive Axles  Ratio of CLC to Maximum Load (“r” factor ) Carried on Any  
Group of Two or More Consecutive Axles.  
2 axles  3 axles  4 axles  5 axles  6 axles  7 axles  8 axles  9 axles  
41 1.000   INSTRUCTIONS:  
1. Determine the scale’s CLC . 
2. Count the number of axles on the vehicle in a given span and determine 
the distance in feet between the first and last axle in the span.  
3. Multiply the CLC by the corresponding multiplier in the table.*  
4. The resulting number is the scale’s maximum concentrated load for a 
single span based on the vehicle configuration.  
* note and formula on next page.  51 1.000   
61 1.000   
71 1.000   
8 and less1 1.000  1.000  
More than 81 1.118  1.235  
9 1.147  1.257  
10 1.176  1.279  
11 1.206  1.301  
12 1.235  1.324  1.471  1.632       
 Table UR.3.2.1.  
Span Maximum Load  
Distance in Feet 
Between the 
Extremes of any 
Two or More 
Consecutive Axles  Ratio of CLC to Maximum Load (“r” factor ) Carried on Any  
Group of Two or More Consecutive Axles.  
2 axles  3 axles  4 axles  5 axles  6 axles  7 axles  8 axles  9 axles  
13 1.265  1.346  1.490  1.651      
14 1.294  1.368  1.510  1.669      
15 1.324  1.390  1.529  1.688  1.853     
16 1.353  1.412  1.549  1.706  1.871     
17 1.382  1.434  1.569  1.724  1.888     
18 1.412  1.456  1.588  1.743  1.906     
19 1.441  1.478  1.608  1.761  1.924     
20 1.471  1.500  1.627  1.779  1.941     
21 1.500  1.522  1.647  1.798  1.959     
22 1.529  1.544  1.667  1.816  1.976     
23 1.559  1.566  1.686  1.835  1.994     
24 1.588  1.588  1.706  1.853  2.012  2.176    
25 1.618  1.610  1.725  1.871  2.029  2.194    
26  1.632  1.745  1.890  2.047  2.211    
27  1.654  1.765  1.908  2.065  2.228    
28  1.676  1.784  1.926  2.082  2.245  2.412   
29  1.699  1.804  1.945  2.100  2.262  2.429   
30  1.721  1.824  1.963  2.118  2.279  2.445   
31  1.743  1.843  1.982  2.135  2.297  2.462   
32  1.765  1.863  2.000  2.153  2.314  2.479  2.647  
33   1.882  2.018  2.171  2.331  2.496  2.664  
34   1.902  2.037  2.188  2.348  2.513  2.680  
35   1.922  2.055  2.206  2.365  2.529  2.697  
36   2.0002 2.074  2.224  2.382  2.546  2.713  
37   2.0002 2.092  2.241  2.400  2.563  2.730  
38   2.0002 2.110  2.259  2.417  2.580  2.746  
39   2.000  2.129  2.276  2.434  2.597  2.763  
40   2.020  2.147  2.294  2.451  2.613  2.779  
41   2.039  2.165  2.312  2.468  2.630  2.796  
42   2.059  2.184  2.329  2.485  2.647  2.813  
43   2.078  2.202  2.347  2.502  2.664  2.829  
44   2.098  2.221  2.365  2.520  2.681  2.846  
45   2.118  2.239  2.382  2.537  2.697  2.862  
46   2.137  2.257  2.400  2.554  2.714  2.879  
47   2.157  2.276  2.418  2.571  2.731  2.895  
48   2.176  2.294  2.435  2.588  2.748  2.912  
49   2.196  2.313  2.453  2.605  2.765  2.928  
50   2.216  2.331  2.471  2.623  2.782  2.945  
51   2.235  2.349  2.488  2.640  2.798  2.961  
52    2.255  2.368  2.506  2.657  2.815  2.978  
53   2.275  2.386  2.524  2.674  2.832  2.994  
54   2.294  2.404  2.541  2.691  2.849  3.011  
55   2.314  2.423  2.559  2.708  2.866  3.028  
56   2.333  2.441  2.576  2.725  2.882  3.044  
57   2.3533 2.460  2.594  2.742  2.899  3.061  
58    2.478  2.612  2.760  2.916  3.077  Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 Table UR.3.2.1.  
Span Maximum Load  
Distance in Feet 
Between the 
Extremes of any 
Two or More 
Consecutive Axles  Ratio of CLC to Maximum Load (“r” factor ) Carried on Any  
Group of Two or More Consecutive Axles.  
2 axles  3 axles  4 axles  5 axles  6 axles  7 axles  8 axles  9 axles  
59    2.496  2.629  2.777  2.933  3.094  
60    2.515  2.647  2.794  2.950  3.110  
*Note:   This table was developed based upon the following formula.  Values may be rounded in some cases for ease of 
use. 
                     
++


−×= 36    12    1 500 NNLNr W  
 
1 Tandem Axle Weight.  
2 Exception – These values in the third column correspond to the maximum loads in which the inner bridge dimensions of 
36, 37, and 38  ft are considered to be equivalent to 39 ft.  This allows a weight of 68  000 lb on axles 2 through  5. 
3 Corresponds to the Interstate Gross Weight Limit.  
 
UR.3.3.  Single -Draft Vehicle Weighing.  – A vehicle or a coupled -vehicle combination shall be 
commercially weighed on a vehicle scale only as a single draft.  That is, the total weight of such a ve hicle or 
combination shall not be determined by adding together the results obtained by separately and not 
simultaneously weighing each end of such vehicle or individual elements of such coupled combination.  
However, the weight of:  
 
(a) a coupled combination may be determined by uncoupling the various elements (tractor, semitrailer, 
trailer), weighing each unit separately as a single draft, and adding together the results; or  
  
(b) a vehicle or coupled -vehicle combination may be determined by adding together the weights obtained 
while all individual elements are resting simultaneously on more than one scale platform.  
 
Note:   This paragraph does not apply to highway -law-enforcement scales and scales used for the collection of statistical 
data.  
(Added 1992)  
 
UR.3.4.  Wheel -Load Weighing.  
 
UR.3.4.1.  Use in Pairs.  – When wheel -load weighers  or portable axle -load weighers  are to be 
regularly used in pairs, both weighers of each such pair shall be appropriately marked to identify them as 
weighers intended to be used in combination.  
 UR.3.4.2.  Level Condition.  – A vehicle of which either an axle -load det ermination or a gross -load 
determination is being made utilizing wheel -load weighers  or portable axle -load weighers , shall be in a 
reasonably level  position at the time of such determination.  
  
 UR.3.5.  Special Designs.  – A scale designed and marked for a special application (such as a prepackaging 
scale or prescription  scale with a counting feature)  shall not be used for other  than its intended purpose31. 
(Amended 2003)  
 
UR.3.6.  Wet Commodities.  – Wet commodities not in watertight containers shall be weighed only on a scale 
having a pan or platform that will drain properly.  
(Amended 1988)  
 UR.3.7.  Minimum Load on a Vehicle Scale.  – A vehicle scale shall not be used to weigh net loads smaller 
than:  
 
(a) 10 d when weighing scrap material for recycling or weighing refuse materials at landfills and transfer 
stations; and  
 (b) 50 d for all other weighing.  
 
As used in this paragraph, scrap materials for recycling shall be limited to ferrous metals, paper (including cardboard), textiles, plastic, and glass.  
(Amended 1988, 1992, and 2006)  
 UR.3.8.  Minimum Load for Weighing Livestock.  – A scale with scale divisions greater than 2  kg (5  lb) 
shall not be used for weighing net loads smaller than 500 d. 
(Amended 1989)  
 
UR.3.9.  Use of Manual Weight Entries.  – Manual gross or net weight entries are permitted  for use in the 
following applications only when:  
 
(a) a point -of-sale system interfaced with a scale is giving credit for a weighed item;  
 
(b) an item is pre -weighed on a legal for trade scale and marked with the correct net weight;  
 
(c) a device or system is generating labels for standard weight packages;  
 
(d) postal scales  or weight classifier s are generating manifests for packages to be picked up at a later time; 
or 
 
(e) livestock  and vehicle scale systems generate weight tickets to correct erroneous tickets.  
(Added 1992) (Amended 2000 and 2004)  
 
                                                           
31 Prepackaging scales and prescription scales with a counting feature (and other commercial devices) used for 
putting up packages in advance of sale are acceptable for use in commerce only if all appro priate provisions of 
NIST Handbook 44 are met.  Users of such devices must be alert to the legal requirements relating to the 
declaration of quantity on a package.  Such requirements are to the effect that, on the average, the contents of the 
individual pa ckages of a particular commodity comprising a lot, shipment, or delivery must contain at least the 
quantity declared on the label.  The fact that a prepackaging scale  may overregister, but within established 
tolerances , and is approved for commercial service is not a legal justification for packages to contain, on the 
average, less than the labeled quantity.  
(Amended 2003)  Handbook 44 – 2015 2016  2.20.  Scales  
  Markup Copy  
  Agency No. 209.02  
 UR.3.10.  Dynamic Monorail Weighing Systems.  – When the value of d is different from the value of  e, 
the commercial transaction must be based on  e. 
(Added 1999)  
 
UR.3.11.  Minimum Count.  – A prescription  scale with an operational counting feature shall not be used to 
count a quantity of less than 30  pieces weighing a minimum of 90  e. 
(Added 2003)  
 
Note:  The minimum count as defined in this paragraph refers to the use of the device in the filling of prescriptions and is 
different from the minimum sample piece count as defined in S.1.2.3. and as required to be marked on the scale by  S.6.6.  
(Note Added 2004)  
 
UR.3.12.  Correct Stored Piece Weight.  – For prescription  scales  with a counting feature , the user is 
responsible for maintaining the correct stored piece weight.  This is especi ally critical when a medicine has been 
reformulated or comes from different lots.  
(Added 2003)  
 
UR.4.  Maintenance Requirements.  
 
UR.4.1.  Balance Condition.  – The zero -load adjustment  of a scale shall be maintained so that, with no load 
on the load -receiving element and with all load -counterbalancing elements of the scale (such as poises, drop 
weights, or counterbalance weights) set to zero, the scale shall indicate or record a zero balance condition .  A 
scale not equipped to indicate or record a zero -load balance shall be maintained in balance under any no -load 
condition.  
 
UR.4.2.  Level Condition.  – If a scale is equipped with a level -condition indicator , the scale shall be 
maintained in level.  
 
UR.4.3.  Scale Modification.  – The dimensions (e.g., length, width, thickness, etc.) of the load receiving 
elemen t of a scale shall not be changed beyond the manufacturer’s specifications, nor shall the capacity  of a 
scale be increased beyond its design capacity by replacing or modifying the original primary indicating or 
recording element with one of a  higher capacity, except when the modification has been approved by a 
competent engineering authority, preferably that of the engineering department of the manufacturer of the scale, and by the weights and measures authority having jurisdiction over the sc ale. 
(Amended 1996)  
 
UR.5.  Coupled- in-Motion Railroad Weighing Systems.  – A coupled -in-motion weighing system placed in 
service on or after January  1, 1991, should be tested in the manner in which it is operated, wit h the locomotive either 
pushing or pulling the cars at the designed speed and in the proper direction.  The cars used in the test train should 
represent the range of gross weights that will be used during the normal operation of the weighing system.  Excep t 
as provided in N.4.2. Weighing Systems Placed in Service Prior to January  1, 1991, and Used to Weigh Trains of 
Ten or More Cars and N.4.3.(a) Weighing Systems Placed in Service on or After January  1, 1991, and Used to 
Weigh Trains of Ten or More Cars, no rmal operating procedures should be simulated as nearly as practical.  
Approach conditions for a train length in each direction of the scale site are more critical for a weighing system used 
for individual car weights than for a unit -train-weights -only fac ility, and should be considered prior to installation.  
(Added 1990) (Amended 1992)  
 
 
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 Section 2.21.  Belt-Conveyor Scale Systems 
 
 
A. Application  
 
A.1. General.  – This code applies to belt -conveyor scale systems and weigh -belt systems used for the weighing of 
bulk materials.  
(Amended 2015)  
 
A.2. Exceptions.  – The code does not apply to:  
 
(a) devices used for discrete weighing while moving on conveyors;  
 
(b) devices that measure quantity on a time basis;  
 
(c) checkweighers; or  
 
(d) controllers or other auxiliary devices except as they may affect the weighing performance of the belt-conveyor scale.  
 A.3. Additional Code Requirements.  – In addition to the requirements of this code, Belt- Conveyor Scale 
Systems shall meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements.  
 
S.1.1.  General. – A belt -conveyor scale shall be equipped with a primary indicating element in the form 
of a master weight totalizer and shall also be equipped with a recording element, and a rate of flow indicator 
and recorder (which may be analog).*  An auxiliary indicator shall not be considered part of the master weight totalizer.  
[*Nonretroactive as of January  1, 1986]  
(Amended 1986)  
 
S.1.2.  Units. – A belt -conveyor scale shall indicate and record weight units in terms of pounds, tons, 
long tons, metric tons, or kilograms.  The value of a scale division (d) expressed in a unit of weight shall be 
equal to: 
 
(a) 1, 2, or  5; or 
 
(b) a decimal multiple or submultiples of  1, 2, or  5. 
 
S.1.3.  Value of the Scale Division.  
 
S.1.3.1.  For Scales Installed After January  1, 1986. – The value of the scale division shall not be 
greater than 0.125 % (
1/800) of the minimum totalized load.  
[Nonretroactive as of January  1, 1986]  
(Added 1985)(Amended 2009)  
 
S.1.3.2.  For Scales Installed Before January  1, 1986. – The value of the scale division shall not be 
greater than 1/1200 of the rated capacity of the device.  However, provision shall be made so that compliance 
with the requirements o f the zero -load test as prescribed in N.3.1. Zero Load Tests may be readily and 
accurately determined in 20  minutes of operation.  
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 S.1.4.  Recording Elements and Recorded Representations. –  The value of the scale division of the 
recording element shall be the same as that of the indicating element.  
 
a) The belt -conveyor scale system shall record the unit of measurement (i.e.,  kilograms, tonnes, pounds, 
tons,  etc.), the date, and the time.  
 
b) The belt-conveyor scale system shall record the initial indication and the final indication of the master 
weight totalizer and the quantity.* 
 
All of the information in  (a) and (b) must be recorded for each delivery.*  
[Nonretroactive as of January  1, 1986]  
[*Nonretroactive as of January  1, 1994]  
(Amended 1993)  
 
S.1.4.1.  The belt -conveyor scale system shall be capable of recording the results of automatic or semi -
automatic zero load tests.**  
[**Nonretroactive as of January  1, 2004]  
(Added 2002)  
 
S.1.5.  Rate of Flow Indicators and Recorders.  - A belt- conveyor scale shall be equipped with a rate of 
flow indicator and an analog or digital recorder.  Permanent means shall be provided to produce an audio or 
visual signal when the rate of flow is equal to or less than 20 % and when the rate of flow is equal to or greater 
than 100 % of the rated capacity of the scale.  The type of alarm (audio or visual) shall be determined by the 
individual installation.  
[Nonretroactive as of January  1, 1986]  
(Amended 1989 and 2004)  
 
S.1.6. Advancement of Primary Indicating or Recording Elements. –  The master weight totalizer 
shall advance only when the belt conveyor is in operation and under load.  
(Amended 1989)  
 
S.1.7.  Master Weight Totalizer. –  The master weight totalizer shall not b e resettable without breaking a 
security means.  
[Nonretroactive as of January  1, 1986]  
 S.1.8.  Power Loss. –  In the event of a power failure of up to 24 hours, the accumulated measured 
quantity on the master weight totalizer of an electronic digital indicator shall be retained in memory during the 
power loss.  
[Nonretroactive as of January  1, 1986]  
(Amended 1989)  
 
S.1.9.  Zero -Ready Indicator.  – A belt- conveyor scale shall be equipped with a zero- ready indicator 
that produces an audio or visual signal when the zero balance is within ±  0.12 % of the rated capacity of the 
scale during an unloaded belt condition.  The type of indication (audio or visual) shall be determined by the 
individual installation.  
[Nonretroactive as of January 1, 2014]   
(Added 2012)  
 
S.2. Design of Weighing Elements.  – A belt -conveyor scale system shall be designed to combine automatically 
belt travel with belt load to provide a determination of the weight of the material that has passed over the scale.  
 
S.2.1.  Speed Measurement. –  A belt -conveyor scale shall be equipped with a belt speed or travel sensor 
that will accurately sense the belt spe ed or travel whether the belt is empty or loaded.  
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 S.2.2.  Adjustable Components. –  An adjustable component that can affect the performance of the 
device (except as prescribed in S.3.1. Design of Zero -Setting Mechanism) shall be held securely in adjustment.  
(Amended 1998)  
 
S.2.3.  Overload Protection. –  The load -receiving elements shall be equipped with means for overload 
protection of not less than 150 % of rated capacity.  The accuracy of the scale in its normal loading range shall 
not be affected by overloading.  
 
S.3. Zero Setting.  
 
S.3.1.  Design of Zero -Setting Mechanism. –  Automatic and semiautomatic zero -setting mechanisms 
shall be so constructed that the resetting operation is carried out only after a whole number of belt revolutions 
and the completion of the setting or the whole operation is indicated.  An audio or visual signal shall be given 
when the automatic and semiautomatic zero- setting mechanisms reach the limit of adjustment of the zero- setting 
mechanism.*  
(Amended 1999 and 2002)  
 Except for systems that record the zero load reference at the beginning and end of a delivery,  the range of the 
zero-setting mechanism shall not be greater than ±  2 % of the rated capacity of the scale without breaking the 
security means.  For systems that record the zero -load reference at the beginning and end of a delivery, the 
range of zero- setting mechanism shall not be greater than 
± 5 % without breaking the security means.**  
[*Nonretroactive as of January  1, 1990]  
[**Nonretroactive as of January  1, 2004]  
(Amended 1989 and 2002)  
 
S.3.1.1.  Automatic Zero -Setting Mechanism. –  The automatic zero- setting mechanism shall indicate or 
record any change in the zero reference.  
[Nonretroactive as of January  1, 2010]  
(Add ed 2009)  
 
S.3.2.  Sensitivity at Zero Load (For Type Evaluation). –  When a system is operated for a time period 
equal to the time required to deliver the minimum test load and with a test load calculated to indicate two scale divisions applied directly to the weighing element, the totalizer shall advance not less than one  or more than 
three scale divisions.  An alternative test of equivalent sensitivity, as specified by the manufacturer, shall also 
be acceptable.  
[Nonretroactive as of January  1, 1986]  
 
S.4. Marking Requirements.  – A beltBelt- conveyor scale  systems and weigh -belt systems  shall be marked with 
the following:  (Also see also G -S.1. Identification.)  
 
(a) the rated capacity in units of weight per hour (minimum and maximum);  
 
(b) the value of the scale division;  
 
(c) the belt speed in terms of feet (or meters) per minute at which the belt will deliver the rated capacity , 
or the maximum and minimum belt speeds at which the conveyor system will be operated for variable 
speed belts ; 
 
(d) the load in terms of pounds per foot or kilograms per meter (determined by  materials material  tests); 
and 
 
(e) the operational temperature range if other than −  10 °C to 40 °C (14  °F to 104  °F). 
[Nonretroactive as of January  1, 1986]  
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S.5. Provision for Sealing.  – A device shall be designed using the format set forth in Table  S.5. with provision(s) 
for applying a security seal that must be broken, or for using other approved means of providing security (e.g. data 
change audit trail available at the time of inspection), before any change that affects the metrological integrity of 
the device can be made to any electronic mechanism.  
[Nonretroactive as of January  1, 1999]  
(Added 1998)  
 
Table S.5.  
Categories of Device and Methods of Sealing 
Categories of Devices  Methods  of Sealing  
Category  1:  No remote configuration 
capability.  Seal by physical seal or two event counters:  one for calibration 
parameters and one for configuration parameters.  
Category  3:  Remote configuration capability.  An event logger is required in the device; it must include an event 
counter (000 to 999), the parameter ID, the date and time of the 
change, and the new value of the parameter.  A printed copy of the 
information must be available through the device or through 
another on -site device.  The event logger shall have a capacity to 
retai n records equal to 10 times the number of sealable 
parameters in the device, but not more than 1000 records are 
required.  ( Note:   Does not require 1000 changes to be stored for 
each parameter.)  
[Nonretroactive as of January  1, 1999]  
(Table Added 1998)  
 
N. Notes  
 
N.1. General.  – Belt-conveyor scales are capable of weighing bulk material accurately.  (Also see Tolerances.)  
However, their performance can be detrimentally affected by the conditions of the installation.  (Also see User 
Requirements.)  The pe rformance of the equipment is not to be determined by averaging the results of the individual 
tests.  The results of all tests shall be within the tolerance limits.  
(Amended 2002)  
 
N.1.1.  Official Test.  – An official test of a belt- conveyor scale system sh all include tests specified in 
N.3.1. Zero Load Tests, N.3.2.  Material Tests, and, if applicable, N.3.3.  Simulated Load Tests.  
(Amended 2006)  
 N.1.2.  Simulated Test.  – Simulated loading conditions as recommended by the manufacturer and 
approved by the offi cial with statutory authority may be used to properly monitor the system operational 
performance between official tests, but shall not be used for official certification.  
(Amended 1991)  
 
N.2. Conditions of Tests.  – A belt -conveyor scale shall be tested after it is installed on the conveyor system with 
which it is to be used and under such environmental conditions as may normally be expected.  Each test shall be 
conducted with test loads no less than the minimum test load.  Before each test run, the inspector shall check the 
zero setting and adjust as necessary.  
(Amended 1986, 2004, and 2009)  
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 N.2.1.  Initial Verification. –  A belt -conveyor scale system or a weigh- belt system shall be verified 
withtested using  a minimum of two test runs  at each of the following flow rates:as indicated in Table N.2.1. 
Initial Verification.  
 
(a) normal use flow rate;  
 
(b) 35 % of the maximum rated capacity; and  
 
(c) an intermediate flow rate between these two points.  
 
Results of the individual test runs in each pair of tests shall not differ by more than the absolute value of the 
tolerance as specified in T.2. Tolerance Values, Repeatability Tests.  All tests shall be within the tolerance as 
specified in T.1. Tolerance Values.  
Test runs may also be conducted at any other rate of flo w that may be used at the installation.  A minimum of 
four test runs may be conducted at only one flow rate if evidence is provided that the system is used at a single 
flow rate constant speed/constant loading setting  and that rate does not vary in either d irection by an amount 
more than 10  % of the normal flow rate that can be developed at the installation for at least 80  % of the time.  
(Added 2004) (Amended 2009 and 2015)  
 Table N.2.1.  
Initial Verification  
Device Configuration  Minimum of Two Test Runs at Each of the Following Settings  Total Tests  
(Minimum)  
Constant Belt Speed and  
Variable Loading  - Belt Loading:  high (normal)  
- Belt Loading:  medium (intermediate)  
- Belt Loading:  low (35  %) 6 
Variable Belt Speed and  
Constant Loading - Belt Speed:  maximum  
- Belt Speed:  medium  
- Belt Speed:  minimum  6 
Variable Belt Speed and  
Variable Loading  
 - Belt Speed:  maximum;  Belt Loading:  high (normal)  
- Belt Speed:  maximum;  Belt Loading:  medium (intermediate)  
- Belt Speed:  maximum; Belt Loading:  low (35  %) 
- Belt Speed:  minimum;  Belt Loading:  high (normal)  
- Belt Speed:  minimum;  Belt Loading:  medium (intermediate)  
- Belt Speed:  minimum; Belt Loading:  low (35  %) 12 
1. Use the device configurations in the left -hand column to identify the scale being tested.   
2. Perform two test runs (minimum) at each of the settings shown in the center column.  
3. The following terminology applies to “Belt Loading”:  
• Low:  35  % of the maximum rated capacity of the system.  
• Medium:  an intermediate rate between the high and low settings.  
• High:  maximum (normal use) operational r ate. 
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 N.2.2.  Subsequent Verification.  – Subsequent testing shall include testing at the normal use flow rate 
and other flow rates used at the installation.  The official with statutory authority may determine that testing only at the normal use flow rate is necessary for subsequent verificati ons if evidence is provided that the system 
is used to operate:  
 
(a) at no less than 70  % of the maximum rated capacity for at least 80  % of the time (excluding time that 
the belt is unloaded); or  
 
(b) with a normal use flow rate that does not vary by more than 10 % of the maximum rated capacity.  
 
Example:  If a belt -conveyor scale system has a maximum rated capacity of 200  tons per hour (tph), and the 
normal use flow rate is 150  tph (75 % of the maximum rated capacity), no testing at additional flow rates is 
required provided the flow rates remain above 140 tph for more than 80 % of the time.  If the same device were 
operating with a normal use flow rate of 130  tph, it is operating at 65  % of the maximum rated capacity.  In this 
case, testing at flow rates in add ition to the normal use flow rate would be required if the normal use flow rate 
varies by more than 20  tph (10  % of the maximum rated capacity).  
(Added 2004)  
 
N.2.3.  Minimum Test Load.   
 
N.2.3.1.  Minimum Test Load, Weigh -Belt Systems. –  The minimum test load shall not be less than the 
largest of the following values: 
 
(a) 800 scale divisions;  
 
(b) the load obtained at maximum flow rate in one revolution of the belt; or  
 
(c) at least one minute of operation.  
(Amended 2015)  
 
N.2.3.2.  Minimum Test Load, All Other Belt-Conveyor Scale Systems.  – Except for applications 
where a normal weighment is less than 10  minutes, the minimum test load shall not be less than the largest 
of the following values .: 
 
(a) 800 scale divisions;  
 
(b) the load obtained at maximum flow rate in one revolution of the belt; or  
 
(c) at least 10  minutes of operation.  
 
For applications where a normal weighment is less than 10  minutes (e.g., belt -conveyor scale systems used 
exclusively to issue net weights for material conveyed by individual vehicles and railway track cars) the 
minimum test load shall be the normal weighment that also complies with N.2.3.2.(a) and  (b). 
 
The official with statutory authority may determine that a smaller minimum totalized load down to 2  % of 
the load totalized in one  hour at  the maximum flow rate may be used for subsequent tests, provided that:  
 
1. the smaller minimum totalized load is greater than the quantities specified in N.2.3.2.(a) and  (b); 
and 
 
2. consecutive official testing with the minimum totalized loads described in N.2.3.2.(a), (b), or  (c) 
and the smaller minimum test load has been conducted that demonstrates the system complies 
with applicable tolerances for repeatability, acceptance, and maintenance.  
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 N.3. Test Procedures.  
 
N.3.1 . Zero -Load Tests.  – A zero -load test shall be conducted to establish that the belt scale system 
(including the conveyor) is capable of holding a stable, in- service zero.  
(Amended 1989 and 2002)  
 
N.3.1.1.  Determination of Zero. –  A zero -load test is a determination of the error in zero, expressed as 
an internal reference, a percentage of the full -scale capacity, or a change in a totalized load over a whole 
number of complete belt revolutions.  A zero -load test shall be performed a s follows:  
 
(a) For belt -conveyor scales with electronic integrators, the test must be performed over a period of at 
least three  minutes and with a whole number of complete belt revolutions.   
 
(b) For belt -conveyor scales with mechanical integrators, the test shall be performed with no less than 
three complete revolutions or 10  minutes of operation, whichever is greater.  
 
(c) For weigh belt systems, the test must be performed over a period of at least one minute and at least 
one complete revolution of the belt.  
(Added 2002)  (Amended 2015)  
 
N.3.1.2.  Test of Zero Stability.  – The conveyor system shall be operated to warm up the belt and the 
belt scale shall be zero adjusted as required.  A series of zero -load tests shall be carried out immediately 
before conducting the simulated load or materials test until the three consecuti ve zero -load tests each 
indicate an error which does not exceed ±  0.06 % of the totalized load at full scale capacity for the duration 
of the test.  No adjustments can be made during the three consecutive zero -load test readings.  
(Added 2002) (Amended 2004 and 2009)  
 
N.3.1.3.  Check for Consistency of the Conveyor Belt along Its Entire Length.  – During a zero -load 
test with any operational low -flow lock -out disabled, the absolute value of the difference between the 
maximum and minimum totalizer readings indicated on the totalizer during any complete revolution of the 
belt shall not exceed 0.12  % of the minimum test load.  
 
Note:   The end value of the zero- load test must meet the ± 0.06 % requirement referenced in the “Test for Zero 
Stability.” 
(Added 2002) (Amended 2004 and 2011)  
 
N.3.2.  Material Tests.  – Material tests should be conducted using actual belt loading conditions.  These 
belt loading conditions shall include, but are not limited to conducting materials tests using different belt 
loading points, all types and sizes of products weighed on the scale, at least one other belt speed, and in both 
directions of weighing.  
 On subsequent verifications, at least two individual tests shall be conducted.  The results of all these tests shall 
be within the tolerance limits.  
 
Either pass a quantity of pre- weighed material over the belt -conveyor scale in a manner as similar as feasible to 
actual loading conditions, or weigh all material that has passed over the belt -conveyor scale.  Means for 
weighing the material test load will depend on the capacity of the belt -conveyor scale and availability of a 
suitable scale for the test.  To assure that the test load is accurately weighed and determined, the following 
precautions shall be observed:  
 
(a) The containers, whether railroad cars, trucks, or boxes, must not leak,  and shall not be overloaded to 
the point that material will be lost.  
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 (b) The actual empty or tare weight of the containers shall be determined at the time of the test.  Stenciled 
tare weight of railway cars or trucks shall not be used.  Gross and tare weight s shall be determined on 
the same scale.  
 (c) When a pre -weighed test load is passed over the scale, the belt -loading hopper shall be examined 
before and after the test to assure that the hopper is empty and that only the material of the test load has passed o ver the scale.  
 (d) Where practicable, a reference scale should be tested within 24  hours preceding the determination of 
the weight of the test load used for a belt- conveyor scale material test.  
 
A reference scale which is not “as found” within maintenance tol erance should have its accuracy 
re-verified after the belt -conveyor test with a suitable known weight load if the “as found” error of the 
belt-conveyor scale material test exceeds maintenance tolerance values.*  
 
(e) If any suitable known weight load other than  a certified test weight load is used for re -verification of 
the reference scale accuracy, its weight shall be determined on the reference scale after the reference 
scale certification and before commencing the belt scale material test.*  
 
(f) The test shall no t be conducted if the weight of the test load has been affected by environmental 
conditions.  
 
*Note:  Even if the reference scale is within maintenance tolerance it may require adjusting to be able to meet paragraph N.3.2.1. Accuracy of Material.  
(Amended 1986, 1989, 1998, 2000, 2002, and 2009)  
 
N.3.2.1.  Accuracy of Material. – The quantity of material used to conduct a material test shall be 
weighed on a reference scale to an accuracy within 0.1  %.  Scales typically used for this purpose include 
Class  III and III L scales or a scale without a class designation as described in Handbook  44, Section  2.20., 
Table  T.1.1. Tolerances for Unmarked Scales.  
(Added 1989) (Amended 1991, 1993, 1998 and 2000)  
 
N.3.3.  Simulated Load Tests.  
 
(a) As required by the official wit h statutory authority, simulated load tests as recommended by the 
manufacturer are to be conducted between material tests to monitor the system’s operational performance, but shall not be used for official certification.  
(Amended 1991)  
 
(b) A simulated load test consisting of at least three consecutive test runs shall be conducted as soon as possible, but not more than 12 hours after the completion of the material test, to establish the factor to 
relate the results of the simulated load test to the results of  the material tests.  
(Added 1990)  
 
(c) The results of the simulated load test shall repeat within 0.1  %. 
(Added 1990)  
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 T. Tolerances  
 
T.1. Tolerance Values.32 – Maintenance and acceptance tolerances on materials tests, relative to the weight of the 
material, shall be ±  0.25 % of the test load.  
(Amended 1993)  
 
T.1.1.  Tolerance Values –  Test of Zero Stability.  – Immediately after material has been weighed over 
the belt -conveyor scale during the conduct of any material test run, the zero -load test shall be repeated.  The 
change in the accumulated or subtracted weight during the zero -load test shall not exceed 0.12  % of the 
totalized load at full scale capacity for the duration of that test.   If the range of zero adjustments during a 
complete (official) verification test exceeds 0.18  % of the totalized load at full scale capacity for the duration of 
the zero -load test, the official with statutory authority may establish an interval for zero -load testing during 
normal operation.  
(Added 2004) (Amended 2009)  
 
T.2. Tolerance Values, Repeatability Tests.  – The variation in the values obtained during the conduct of 
materials tests shall not be greater than 0.25  % (1/400). 
 
T.3. Influence Factors.  – The following factors are applicable to tests conducted under controlled conditions 
only, provided that:  
 
(a) types of devices approved prior to January  1, 1986, and manufactured prior to January  1, 1988, need not 
meet the requirements of this section;  
 (b) new types of devices submitted for approval after January  1, 1986, shall comply with the requirements of 
the se ction; and  
 
(c) all devices manufactured after January  1, 1988, shall comply with the requirements of this section.  
 
T.3.1.  Temperature.  – Devices shall satisfy the tolerance requirements at temperatures from 
− 10 °C to 40 °C (14  °F to 104 °F). 
 
T.3.1.1.  Effect on Zero -Load Balance.  – The zero -load indication shall not change by more than 
0.035  % of the rated capacity of the scale (without the belt) for a change in temperature of 10  °C (18  °F) at 
a rate not to exceed 5  °C (9 °F) per hour.  
(Amended 2004)  
 
T.3.1.2.  Temperature Limits. –  If a temperature range other than −  10 
°C to 40 °C (14  °F to 104 °F) is 
specified for the device, the range shall be at least 30 °C (54  °F). 
[Nonretroactive as of January  1, 1990]  
                                                           
32 The variables and uncertainties included in the relative tolerance represent only part of the  variables 
that affect the accuracy of the material weighed on belt- conveyor scales.  If this tolerance was based on 
an error analysis beginning with mass standards through all of the test processes and following the 
principle expressed in Section  3.2. of the Fundamental Considerations in Appendix  A, the tolerance 
would be 0.5  %. 
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 (Added 1989)  
 
T.3.2.  Power Supply, Voltage, and Frequency.  – A belt -conveyor scale system shall satisfy the 
tolerance requirements over a range of 100  V to 130 V or 200 V to 250  V as appropriate and over a frequency 
range of 59.5 Hz to 60.5 Hz. 
 
UR. User Requirements  
 
UR.1.  Installation Requirements .  
 
UR.1.1.  Protection from Environmental Factors.  – The indicating elements, the lever system or load cells, 
and the load -receiving element of a belt -conveyor scale shall be adequately protected from environmental 
factors such as wind, moisture, dust, weather, and radio frequency interference (RFI) and electromagnetic 
interference (EMI) that may adversely affect the operation or performance of the device.  
 
UR.1.2.  Conveyor Installation.  – The design and installation of the conveyor leading to and from the 
belt-conveyor scale is critical with respect to scale performance.  Installation shall be in accordance with the 
scale manufacturer’s instructions and the following:  
 
(a) Installation - General. – A belt -conveyor scale shall be so installed that neither its 
performance nor operation will be adversely affected  by any characteristic of the 
installation, including but not limited to, the foundation, supports, covers, or any other 
equipment.  
(Amended 2002)  
 
(b) Live Portions of Scale. –  All live portions of the scale shall be protected with 
appropriate guard devices and clearances, as recommended by the scale manufacturer, to 
prevent accidental interference with the weighing operation.  (Also see UR.3.1. Scale 
and Conveyor Maintenance.)  
(Amended 2004)  
 
(c) Storage of Simulated Load Equipment. –  Suitable protection shall be  provided for 
storage of any simulated load equipment.  
 
(d) Take -up Device. –  Any take -up device shall provide constant and consistent tension for 
the belt under all operating conditions.  
(Amended 2014)  
(e) Scale Location and Training Idlers. –  The scale shall be so installed that the first 
weigh idler of the scale is at least 6  m (20  ft) or five idler spaces, whichever is greater, 
from loading point, skirting, head or tail pulley, or convex curve in the conveyor.  Any training idler shall be located at least 18  m (60 ft) from the centerline of the weigh span 
of the scale.  Training idlers shall not be restrained at any time in order to force belt 
alignment.  
(Amended 1998)  
 
(f) Concave Curve. – If there is a concave curve in the conveyor, before or after the scale, 
the scale shall be installed so that the belt is in contact with all the idler rollers at all 
times for at least 6  m (20  ft) or five idler spaces, whichever is greater, before and after Handbook 44 –  20152016   2.21.  Belt -Conveyor Scale Systems  
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 the scale.33  A concave curve shall start no closer than 12  m (40  ft) from the scale to the 
tangent point of the concave curve.  
(Amended 1998)  
 
(g) Tripper and Movable Pulleys. –  There shall be no tripper or movable head pulleys in the conveyor.  
 
(h) Conveyor Orientation. –  The conveyor may be horizontal or inclined, but, if inclined, the angle shall be 
such that slippage of material along the belt does not occur.  
  
(i) Conveyor Stringers. –  Conveyor stringers at the scale and for not less than 6  m (20  ft) before and 
beyond the scale shall be continuous or securely joined and of s ufficient size and so supported as to 
eliminate relative deflection between the scale and adjacent idlers when under load.  The conveyor 
stringers should be so designed that the deflection between any two adjacent idlers within the weigh area 
does not exceed 0.6 mm (0.025  in) under load.  
 
(j) Identification of Scale Area. –  The scale area and five idlers on both ends of the scale shall be of a 
contrasting color, or other suitable means shall be used to distinguish the scale from the remainder of the 
conveyor installation, and the scale shall be readily accessible.  
(Amended 1998)  
 
(k) Belt Composition and Maintenance. –  Conveyor belting shall be no heavier than is required for normal 
use. – In a loaded or unloaded condition, the belt shall make constant contact wit h horizontal and wing 
rollers of the idlers in the scale area.  Splices shall not cause any undue disturbance in scale operation.  
(Also see N.3. Test Procedures.)  
(Amended 1998, 2000, 2001, and 20012015 ) 
 
(l) Uniformity of Belt Loading and Flow. –  The conveyo r loading mechanism shall be designed to 
provide uniform belt loading.  The distance from the loading point to the scale shall allow for adequate 
settling time of the material on the belt before it is weighed.  Feeding mechanisms shall have a positive 
closing or stopping action so that material leakage does not occur.  Feeders shall provide an even flow 
over the scale through the full range of scale operation.  Sufficient impact idlers shall be provided in the 
conveyor under each loading point to prevent de flection of the belt during the time material is being 
loaded.  
 
(m) Belt Alignment. –  The belt shall not extend beyond the edge of the outermost roller of any carry side 
(top) roller in any area of the conveyor nor touch the conveyor structure on the return (b ottom) side of 
the conveyor.  
(Amended 1998 and 2008)  
(Amended 2002, 2012, 2013, 2014, and 20142015)  
 
UR.1.3. Material Test.  – A belt- conveyor scale shall be installed so that a material test can be conveniently 
conducted.  
[Nonretroactive as of January  1, 1981]  
                                                           
33 Installing the belt scale five -idler spaces from the tail pulley or the infeed skirting will be in the area of least belt 
tension on the conveyor and should produce the best accuracy.  The performance of a belt -conveyor scale may be 
adversely affected by a concave curve in the conveyor that is located between the loading point and the scale.  
Therefore, whenever possible, a belt -conveyor scale should not be installed with a concave curve in the conveyor 
between the loading point and the scale.  
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UR.1.4.  Belt Travel (Speed or Velocity).  – The belt travel sensor shall be so positioned that it accurately 
represents the travel of the belt over the scale for all flow rates between the maximum and minimum values.  
The belt travel senso r shall be so designed and installed that there is no slip.  
(Amended 2012)  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Rate of Operation. –  A belt -conveyor scale system shall be operated between 20  % and 100 % of 
its rated capacity.  
 (Amended 2004)  
 
UR.2.2.  Minimum Totalized Load.  – Delivered quantities of less than the minimum test load shall not be 
considered a valid weighment.  
 
UR.2.3.  Security Means.  – When a security means has been broken, it shall be reported to the official with 
statutory authority.  
(Amended 1 991) 
 
UR.2.4.  Loading.  – The feed of material to the scale shall be controlled to assure that, during normal 
operation, the material flow is in accordance with the manufacturer’s recommendation for rated capacity.  
 UR.2.5.  Diversion or Loss of Measured Pro duct.  – There shall be no operation(s) or condition(s) of use 
that result in loss or diversion that adversely affects the quantity of measured product.  
(Added 2005)  
 
UR.2.6.  Retention of Maintenance, Test, and Analog or Digital Recorder Information.  – Records of 
calibration and maintenance, including conveyor alignment, analog or digital recorder, zero -load test, and 
material test data shall be maintained on site for at least the three concurrent years as a history of scale 
performance.  Copies of any r eport as a result of a test or repair shall be mailed to the official with statutory 
authority as required.  The current date and correction factor(s) for simulated load equipment shall be recorded 
and maintained in the scale cabinet.  
(Added 2002)  
(Amende d 2012)  
 
UR.3.  Maintenance Requirements . 
 
UR.3.1.   – Scale and Conveyor Maintenance.  – Belt- conveyor scales – Weighing systems  and idlers shall be 
maintained and serviced in accordance with manufacturer’s instructions and the following:  
 
(a) Zero Balance.  – The zero balance condition of a belt -conveyor scale shall be maintained such that, 
prior to beginning any commercial transaction, with no load on the belt, the zero balance condition is 
within ± 0.12 % of the scale’s rated capacity.  
(Added 2012)  
 
(b) Scale Clearance. – The scale and area surrounding the scale shall be kept clean of debris or other 
foreign material that can detrimentally affect the performance of the system.  
 (c) Weighed Material. –  There shall be provisions to ensure that weighed material does not adhere to the 
belt and return to the scale system area.  
(Added 2004)  
 (d) Simulated and Zero -Load Test Intervals. –  Zero -load tests and simulated load or material tests  shall 
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 the conveyor system  in order to provide reasonable assurance that the device is performing correctly.  
The minimum interval for periodic zero -load tests and simulated load tests shall be established by the 
official with statuto ry authority or according to manufacturer recommendations.  
 
The actions to be taken as a result of the zero -load test are shown in the following table.  
 
Change in Zero (∆ 0)  Actions to be Taken  
If the change in zero is less than ±  0.25 % 
(∆ 0 < 0.25  %) Perform zero adjustment and proceed to simulated load test.  
If the change in zero is ± 0.25  % to ± 0.5  % 
(0.25  % ≤ ∆ 0 ≤ 0.5  %) Inspect the conveyor and weighing area for compliance with 
UR.1. Installation Requirements and repeat the zero -load test.  
If the change in zero is greater than ±  0.5 % 
(∆ 0 > 0.5  %) Inspect the conveyor and weighing area for compliance with 
UR.1. Installation Requirements, repeat the zero -load test, 
and reduce the interval between zero -load tests.  
 
The action to be taken as a result of the simulated load or material tests is shown in the following 
table.  
 
Change in Factor (Reference) Established in 
N.3.3.(b)  
[∆ N.3.3.(b)]  Action to be Taken  
If the error is less than 0.25  % 
(∆ N.3.3.(b) < 0.25  %) No Action  
If the error is at least 0.25  % but not more than 
0.6 % 
(0.25  % ≤ ∆ N.3.3.(b) ≤ 0.6  %) Inspect the conveyor and weighing area for compliance with 
UR.1. Installation Requirements and , after compliance is 
verified, repeat the test.  
 
If the result of that test remains greater than ± 0.25 %, a span 
correction shall be made and the official with statutory 
authority notified.  
(Amended 1991)  
If the error is greater than 0.6  % but does not exceed 
0.75 % 
(0.6 % < ∆ N.3.3.(b) ≤ 0.75  %) Inspect the conveyor and weighing area for compliance with 
UR.1. Installation Requirements and , after compliance is 
verified,  repeat the test.  
 If the result of that test remains greater than ±  0.25 %, a span 
correction shall be made, the official with statutory authority 
shall be notified, and an official test shall be conducted.  
(Amended 1991)  
If the error is greater than 0.75  % 
(∆ N.3.3.(b) > 0.75  %) An official test is required.  
(Amended 1987)  
(Amended 2002 and 2009)  
 
(e) Scale Alignment.  – Alignment checks shall be conducted in accordance with the manufacturer’s 
recommendation  when conveyor work is performed in the scale area. .  A material test is required after 
any realignment.  
(Amended 1986, 2000,  and 20002015)  
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 (f) Simulated Load Equipment.  – Simulated load equipment shall be clean and properly maintained.  
 
(g) Zero Load Reference Information.  – When zero load reference information is recorded for a 
delivery, the information must be based upon zero load tests performed as a minimum bot h 
immediately before and immediately after the totalized load.  
(Added 2002)  
(Amended 1986, 2000, 2002, 2004, 2009, 2012, and 2012)  
(Amended 20122015)  
 
UR.4.  Compliance.  – Prior to initial verification, the scale manufacturer or installer shall certify to the owner that 
the scale meets code requirements.  Prior to initial verification and each subsequent verification, the scale owner or 
his agent shall notify the official with statutory authority in writing that the belt -conveyor scale system is in 
complianc e with this specification and ready for material testing.  
(Amended 1991)  
 
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 Section 2.22.  Automatic Bulk Weighing Systems34 
 
 
A. Application  
 
A.1. General.  – This code applies to automatic bulk weighing systems, that is, weighing systems adapted to the 
automatic weighing of a commodity in successive drafts of predetermined amounts automatically recording the 
no-load and loaded weight values and accumulating the net weight of each draft.  
(Amended 1987)  
 
A.2. Additional Code Requirements . – In addition to the requirements of this code, Automatic Bulk Weighing 
Systems shall meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and Recorded Representations.  
 
S.1.1.  Zero Indication.  – Provisions shall be made to indicate and record a no -load reference value and, 
if the no -load reference value is a zero value indication, to indicate and record an out -of-balance condition on 
both sides of zero.  
 
S.1.1.1.  Digital Zero Indication.  – A digital zero indication shall represent a balance condition that is 
within ±  ½ the value of the scale division.  
 
S.1.2.  Value of Scale Division  (d). – The value of the s cale division  (d), expressed in a unit of weight, 
shall be equal to:  
 
(a) 1, 2, or  5; or  
 
(b) a decimal multiple or submultiple of 1, 2, or  5; or  
 (c)  a binary  submultiple of a unit of weight.  
 
Examples:  Scale divisions may be 0.01, 0.02, or  0.05; 0.1, 0.2, or  0.5; 1, 2, or  5; 10, 20, or  50; or ½, ¼, 
⅛, 1/16, etc.  
[Nonretroactive as of January  1, 1986]  
(Amended 1987)  
 
S.1.3.  Capacity Indication and Recorded Representation.  – An indicating or recording element shall 
not indicate or record any values when the gross load is in excess of 105  % of the capacity of the system.  
 
S.1.4.  Weighing Sequence.  – For systems used to receive (weigh in), the no -load reference value shall 
be determined and recorded only at the beginning of each weighing cycle.  For systems used to deliver (weigh 
out), the no -load reference value shall be determined and recorded only after the gross load reference value for 
each weighing cycle has been indicat ed and recorded.  
 
                                                           
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 S.1.5.  Recording Sequence.  – Provision shall be made so that all weight values are indicated until the 
completion of the recording of the indicated value.  
 
S.1.6.  Provision for Sealing Adjustable Components on Electronic Devices.  – Provis ion shall be 
made for applying a security seal in a manner that requires the security seal to be broken before an adjustment can be made to any component affecting the performance of the device.  
 
S.2. Design of Balance and Damping Mechanism.  
 
S.2.1.  Zero -Load Adjustment.  – The weighing system shall be equipped with manual or semiautomatic 
means by which the zero -load balance or no -load reference value indication may be adjusted.  Automatic 
zero-tracking and automatic zero -setting mechanisms are prohibited.  
(Amended 2010)  
 
S.2.1.1.  Manual.  – A manual zero -load or no- load reference value setting mechanism shall be operable 
or accessible only by a tool outside of or entirely separate from this mechanism or enclosed in a cabinet.  
 
S.2.1.2.  Semiautomatic.  – A semiautomatic zero -load or no- load reference value setting mechanism 
shall meet the provisions of S.2.1.1. or shall be operable only when:  
 
(a) the indication is stable within ±  3 scale divisions; and  
 
(b) cannot  be operated during a weighing operation.  
 
S.2.2.  Damping Means.  – A system shall be equipped with effective means necessary to bring the 
indications quickly to a readable, stable equilibrium.  Effective means shall also be provided to permit the 
recording  of weight values only when the indication is stable within plus or minus three scale divisions for 
devices with 10  000 scale divisions, or plus or minus one division for devices with less than 10 000 scale 
divisions.  
 
S.3. Interlocks and Gate Control.  
 
S.3.1.  Gate Position.  – Provision shall be made to clearly indicate to the operator the position of the 
gates leading directly to and from the weigh hopper.  
 
S.3.2.  Interlocks.  – Each automatic bulk weighing system shall have operating interlocks to provid e for 
the following:  
 
(a) Product cannot be cycled and weighed if the weight recording element is disconnected or subjected to 
a power loss.  
 (b) The recording element cannot print a weight if either of the gates leading directly to or from the weigh 
hoppe r is open.  
 
(c) A “low paper” sensor, when provided, is activated.  
 (d) The system will operate only in the proper sequence in all modes of operation.  
 (e) When an overfill alarm is activated, the system shall indicate and record an overfill condition.  
(Amended  1993)  
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 S.3.3.  Overfill Sensor.  
 
(a) The weigh hopper shall be equipped with an overfill sensor which will cause the feed gate to close, 
activate an alarm, and inhibit weighing until the overfill condition has been corrected.  
(Added 1993)  
 (b) If the system is equipped with a lower garner or surge bin, that garner shall also be equipped with an 
overfill sensor  which will cause the gate of the weigh hopper to remain open, activate an alarm, and 
inhibit weighing until the overfill condition has been c orrected.  
[Nonretroactive as of January  1, 1998]  
(Amended  1997)  
 
S.4. Design of Weighing Elements.  
 
S.4.1.  Antifriction Means.  – At all points at which a live part of the mechanism may come into contact 
with another part in the course of normal usage, frictional effects shall be reduced to a minimum by means of 
suitable antifriction means, opposing surfaces and points being prope rly shaped, finished, and hardened.  
 
S.4.2.  Adjustable Components.  – An adjustable component, such as a potentiometer, shall be held 
securely in adjustment and, except for a component for adjusting level or a no -load reference value, shall not be 
adjustabl e from the outside of the device.  
 
S.4.3.  Multiple Load -Receiving Elements.  – A system with a single indicating or recording element, or 
a combination indicating recording element, that is coupled to two or more load- receiving elements with 
independent wei ghing systems, shall be provided with means to prohibit the activation of any load -receiving 
element (or elements) not in use, and shall be provided with automatic means to indicate clearly and definitely which load -receiving element (or elements) is in us e. 
 
S.4.4.  Venting.  – All weighing systems shall be vented so that any internal or external pressure will not 
affect the accuracy or operation of the system.  
 S.5. Marking Requirements.   (Also see Section 1.10. General Code paragraph G -S.1. Identification.)  
 
S.5.1.  Capacity and Value of the Scale Division.  – The capacity of the weighing system and the value 
of the scale division shall be clearly and conspicuously marked on the indicating  element near the weight value 
indications.  
 S.5.2.  Weighing Elements.  – On a weighing element not permanently attached to an indicating element, 
there shall be clearly and permanently marked for the purposes of identification, the name, initials, or trademark 
of the manufacturer, the manufacturer’s designation that positively identifies the pattern or design, and the 
nominal capacity.  
 
S.5.3.  Temperature Limits.  – Unless the temperature range is −  10 °C to +  40 °C (14  °F to 104 °F), the 
temperature range shall be marked on the device.  
[Nonretroactive as of January  1, 1986]  
(Added 1985)  
 
S.5.4.  Accuracy Class.  
 
(a) All systems used to weigh grain shall be marked Class  III.* 
 (b) All other systems shall be marked either Class III or III L.* 
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 (*Also see Section  2.20. Scales Code for the parameters for these accuracy classes for scales.  The specific 
requirements for automatic bulk weighing systems apply to these devices  when there is a conflict between the 
Scales Code and the Automatic Bulk Weighing Systems Code.)  
[Nonretroactive as of January  1, 1986]  
(Added 1985) (Amended 1992)  
 
N. Notes  
 
N.1. Testing Procedures.  
 
N.1.1.  Test Weights.  – The increasing load test shall be conducted using test weights equal to at least 
10 % of the capacity of the system:  
 
(a) on automatic grain bulk -weighing systems installed after January 1, 1984; and  
 
(b) on other automatic bulk -weighing systems installed a fter January  1, 1986.  
(Amended 1987)  
 
N.1.2.  Increasing -Load Test.  – An increasing -load test consisting of substitution  and strain -load tests 
shall be conducted up to the used capacity of the weighing system.  
(Amended 1987)  
 N.1.3.  Decreasing -Load Test.  – A decreasing -load test shall be conducted on devices used to weigh out.  
(Added 1986)  
 N.1.4.  Zero -Balance or No -Load Reference Value Change Test.  – A test for change of zero -balance or 
no-load reference value shall be conducted on all scales after the r emoval of any test load.  The change shall not 
be more than the minimum tolerance applicable . 
 
N.1.5.  Discrimination Test.  – A discrimination test shall be conducted on all automatic indicating scales 
with the weighing device in equilibrium at zero- load and at maximum test load, and under controlled conditions 
in which environmental factors are reduced to the extent that they w ill not affect the results obtained.  
[Nonretroactive as of January  1, 1986]  
 
N.1.5.1.  Digital Device.  – On a digital device, this test is conducted from just below the lower edge of the 
zone of uncertainty for increasing -load tests, or from just above the upper edge of the zone of uncertainty 
for decreasing -load tests.  
(Added 1987)  
 
N.2. Verification (Testing) Standards.  – Standard weights and masses used in verifying weighing devices shall 
comply with requirements of NIST Handbook  105-1 (Class  F) or the to lerances expressed in Appendix  A, 
Fundamental Considerations, paragraph  3.2. (i.e., one-third of the smallest tolerance applied).  
 
T. Tolerances  
 T.1. Tolerance Application.  – Tolerance values shall be applied to all indications and recorded representations of 
a weighing system.  
 
T.1.1.  To Errors of Underregistration  and Overregistration.  – The tolerances hereinafter prescribed 
shall be applied equally to errors of underregis tration  and errors of overregistration . 
 
T.1.2.  To Increasing -Load Tests.  – Basic tolerances shall be applied.  
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 T.1.3.  To Decreasing -Load Tests.  – Basic tolerances shall be applied to systems used to weigh out.  
(Added 1986)  
 
T.1.4.  To Tests Involving Digital Indications or Representations.  – To the tolerances that would 
otherwise be applied, there shall be added an amount equal to one -half the value of the scale division.  This does 
not apply to digital indications or recorded represen tations that have been corrected for rounding using error 
weights.  
(Added 1986)  
T.2. Minimum Tolerance Values.  – The minimum tolerance value shall not be less than half the value of the 
scale division.  
 
T.2.1.  For Systems Used to Weigh Construction Materials.  – The minimum maintenance and 
acceptance tolerance shall be 0.1  % of the weighing capacity of the system, or the value of the scale division, 
whichever is less.  
(Added 1986)  
 
T.3. Basic Tolerance Values.  
 
T.3.1.  Acceptance Tolerance.  – The basic acceptance tolerance shall be one- half the basic maintenance 
tolerance.  
 
T.3.2.  For Systems Used to Weigh Grain.  – The basic maintenance tolerance shall be 0.1  % of test 
load. 
 
T.3.3.  For All Other Systems.  – The basic maintenance tolerance shall be 0.2  % of test load . 
(Amended 1986)  
 
T.4. Time Dependence.  – At constant test conditions, the indication 20  seconds after the application of a load and 
the indication after one  hour shall not differ by more than the absolute value of the applicable tolerance for the 
applied load.  
[Nonretroactive  and enforceable as of January  1, 1987]  
(Added 1986)  
 
T.5. Repeatability . – The results obtained by several weighings of the same load under reasonably static test 
conditions shall agree within the absolute value of the maintenance tolerance for that load, and shall be within  
applicable tolerances.  
(Added 1986)  
 
T.6. Discrimination, Digital Automatic Indicating Scales.  – A test load equivalent to 1.4  d shall cause a change 
in the indicated or recorded value of at least 2.0  d.  This requires the zone of uncertainty to be not gr eater than 
0.3 times the value of the scale division.  
(Added 1985)  
 
T.7. Influence Factors.  – The following factors are applicable to tests conducted under controlled conditions 
only, provided that:  
 
(a) types  of devices approved prior to January  1, 1986, and manufactured prior to January  1, 1988, need not 
meet the requirements of this section; and  
 
(b) new types of devices submitted for approval after January  1, 1986, shall comply with the requirements of 
this section; and  
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 (c) all devices manufactured after January  1, 1988, shall comply with the requirements of this section.  
[Nonretroactive  as of January  1, 1986]  
 
T.7.1.  Temperature.  – Devices shall satisfy the tolerance requirements under the following temperature 
conditions:  
 
T.7.1.1.  If not marked on the device, the temperature limits shall be:   − 10 °C to 40 °C (14 °F to 
104 °F). 
 
 T.7.1.2.  If temperature limits are specified for the device, the range shall be at least 30 °C (54  °F). 
 T.7.1.3.  Temperature Effect on Zero -Load Balance.  – The zero -load indicator shall not vary by more 
than one  division per 5 °C (9  °F) change in temperature . 
 T.7.1 .4. Operating Temperature.  – An indicating or recording element shall not display or record any 
usable values until the operating temperature necessary for accurate weighing and a stable zero- balance 
condition has been attained.  
[Nonretroactive  as of January  1, 1986]  
 
T.7.2.  Barometric Pressure.  – The zero indication shall not vary by more than one scale division for a 
change in barometric pressure of 1 kPa over the total barometric range of 95 kPa to 105  kPa (28 in to 31  in of 
mercury).  
[Nonretroactive  as of January  1, 1986]  
 
T.7.3.  Electric Power Supply.  
 
T.7.3.1.  Power Supply, Voltage, and Frequency.  
 
(a) Weighing devices that operate using alternating current must perform within the conditions 
defined in paragraphs  T.2. through T.7., inclusive over the line voltage range of 100  V to 130 V or 
200 V to 250 V rms as appropriate and over the frequency range of 59.5  Hz to 60.5  Hz. 
 
(b) Battery -operated instruments shall not indicate nor record values outside the applicable tolerance 
limits when  battery power output is excessive or deficient.  
 
T.7.3.2.  Power Interruption.  – A power interruption shall not cause an indicating or recording element 
to display or record any values outside the applicable tolerance limits.  
[Nonretroactive  as of January  1, 1986]  
(Added 1985)  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1. For Systems used to Weigh  Grain. – The number of scale divisions of a weighing system shall not 
be less than 2 000 nor greater than 10 000 divisions.  
[Nonretroactive  as of January  1, 1984]  
(Amended 1986 and 1992)  
 
U.R.1.2.  For Systems used to Weigh  Commodities other than Grain.  – The number of scale divisions shall 
not be less than 500 nor greater than 10 000. 
[Nonretroactive  as of January  1, 1987]  
(Adde d 1986)  
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 UR.2.  Installation Requirements.  
 
UR.2.1.  Protection from Environmental Factors.  – The indicating elements, the lever system or load cells, 
the load -receiving element, and any permanently installed test weights shall be adequately protected from 
environmental factors such as wind, weather, and RFI that may adversely affect the operation or performance of 
the system.  
 
UR.2.2.  Foundation, Supports, and Clearance.  – The foundation and supports of any system shall be such 
as to provide strength, rigidity, and permanence  of all components, and clearance shall be provided around all 
live parts so that no contact can result before or during operation of the system.  
 
UR.3. Loading Requirements.  
 
UR.3.1.  For Systems Used to Weigh Grain.  – A system shall not be used to weigh drafts less than 40  % of 
the weighing capacity of the system except for a final partial draft.  Loads shall not normally be retained on the 
weighing e lement for a period longer than a normal weighing cycle.  
(Amended 1986)  
 
UR.3.2. For Systems Used to Weigh Commodities Other than Grain.  – A system shall not be used to weigh 
drafts less than 20 % of the weighing capacity of the system except for a final partial draft.  Loads shall not 
normally be retained on the weighing element for a period longer than a normal weighing cycle.  
[Nonretroactive as of January  1, 1987]  
(Added 1986)  
 UR.4.  System Modification.  – The weighing system shall not be modified except  when the modification has been 
approved by a competent engineering authority, preferably that of the engineering department of the manufacturer of 
the scale, and the official with statutory authority having jurisdiction over the scale.  
(Amended 1991)  
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 Section 2.23. Weights  
 
 
A. Application  
 
A.1. General.  – This code applies to commercial weights; that is, weights used in connection with commercial 
weighing devices.  
 
A.2. Exceptions.  – This code does not apply to test weights or to other “standards” of mass.  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, Weights shall meet the 
requirements of Section 1.10. General Code.  
 
S. Specifications  
 S.1. Material.  – The material used for weights shall be as follows:  
 
(a) Weights of 6  g or 100 gr and larger shall be made of a metal, or a metal alloy, not softer than brass.  
 
(b) Weights of less than 6  g or 100 gr may be made of aluminum, but shall not be made of iron or of unplated 
steel, except stainless steel.  
 
S.2. Design.  
 
S.2.1.  Surface.  – The surface of a weight shall be smooth and shall not be coated with thick, soft, or brittle 
material.  A weight of more than 2  g or 30 gr or shall not have sharp edges, points, or corners.  
 
S.2.2.  Ring.  – A ring on a weight shall not be split or remova ble. 
 
S.3. Adjusting Material.  – Adjusting material shall be securely positioned and shall not project beyond the 
surface of the weight.  
 
S.4. Marking Requirements.  
 
S.4.1.  General.  – A weight shall be marked to show clearly its nominal value, which shall include 
identification of the unit; however, the nominal value of a weight of 30  gr or 2  g, or less, may be designated by 
dots, lines, figures, distinctive shape, or other appropria te means.  
 
S.4.2.  Apothecaries’ Weights.  – On apothecaries’ dram, ounce, and pound weights, the letters “ap” shall be 
used in combination with the nominal value and the appropriate abbreviation of or symbol for the unit.  
 
S.4.3.  Troy Weights.  – On troy ounce and pound weights, the letter “t” shall be used in combination with the 
nominal value and the appropriate symbol of the unit.  
 S.4.4.  Metric Weights.  – On metric weights, the symbols “kg,” “g,” and “mg” shall be used in combination 
with th e nominal value of kilograms, grams, and milligrams, respectively.  
 
S.4.5.  Carat Weights.  – On carat weights, the letter “c” shall be used in combination with the nominal value.  
 
S.4.6.  Counterpoise Weight.  – A counterpoise weight shall be marked to show c learly both its nominal 
value and the value it represents when used on the multiplying -lever scale for which it is intended.  
 2.23.  Weights  Handbook 44 –  20152016  
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 N. Notes  
 
N.1. Testing Procedures.  – Commercial weights should be tested on a precision balance using standard weights, 
the errors  of which, when used without correction, do not exceed 1/3 of the smallest tolerance to be applied.  (Also 
see Appendix  A, Fundamental Considerations, paragraphs  3.2. Tolerance for Standards Standars  and 3.3. Accuracy 
of Standards.)  
 
T. Tolerances  
 
T.1. In Excess and In Deficiency.  – The tolerances hereinafter prescribed shall be applied equally to errors in 
excess and errors in deficiency.  
 T.2. On Avoirdupois Weights.  – The maintenance tolerances shall be as shown in Table 1. Maintenance 
Tolerance for Avoi rdupois Weights.  Acceptance tolerances shall be one -half the maintenance tolerances.  
   Handbook 44 –  20152016  2.23.  Weights  
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 Agency No. 209.02  
 Table 1.  
Maintenance Tolerance for Avoirdupois Weights  
Maintenance Tolerance 
Nominal 
Value  Equal -Arm  
Weights  Counterpoise Weights  
For scales with multiples of 
less than 1000  For scales with multiples of 
1000 or over  
oz Grains  mg grains  mg grains  mg 
1/64 0.1 6     
1/32 0.3 19     
1/16 0.4 26     
1/8 0.5 32     
¼ 1.0 65     
½ 1.5 97 1.0 65   
1 1.7 110 1.0 65   
2 2.0 130 1.0 65   
3 2.0 130 1.5 97   
4 3.0 190 1.5 97 1.0 65 
5 3.5 230 1.5 97 1.0 65 
6 3.5 230 1.5 97   
8 4.0 260 2.0 130 1.5 97 
10 4.0 260 2.5 160 2.0 130 
12 5.0 320 2.5 160 2.0 130 
Lb Grains  mg grains  mg grains  mg 
1 5.0 320 3.0 190 2.5 160 
2 7.0 450 6.0 390 4.0 260 
3 9.0 580 9.0 580 5.0 320 
4 11.0 710 11.0 710 6.0 390 
5 15.0 970 12.0 780 6.5 420 
6 17.0 1190      
7 19.0 1200      
8 21.0 1400  15.0 970 9.0 580 
9 23.0 1500      
10 25.0 1600  18.0 1160  10.0 650 
15 28.0 1800      
20 30.0 1900      
25 35.0 2300      
30 40.0 2600      
40 45.0 2900      
50 50.0 3200      2.23.  Weights  Handbook 44 –  20152016  
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 T.3. On Metric Weights.  – The maintenance tolerances shall be as shown in Table 2. Maintenance Tolerances for 
Metric Weights.  Acceptance tolerances shall be one- half the maintenance tolerances.  
 
T.4. On Carat Weights.  – The maintenance tolerances shall be as shown in Table 2. Maintenance Tolerances for 
Metric Weights.  Acceptance tolerances shall be one- half the maintenance tolerances.  
 
Table 2.  
Maintenance Tolerances for Metric Weights  
Nominal  
Value  
(mg)  Maintenance  
Tolerance 
(mg)  Nominal  
Value  
(g) Maintenance  
Tolerance 
(mg)  
5 or less  
10 
20 
30 
50 
100 
200 
300 
500 
 
 
 0.1 
0.3 
0.4 
0.6 
0.8 
1.0 
1.5 
2.0 
3.0 
 
  1 
2 
3 
5 
10 
20 
30 
50 
100 
200 
300 
500 4 
6 
8 
10 
15 
20 
30 
40 
70 
100 
150 
175 
Nominal  
Value  
(kg) Maintenance  
Tolerance 
(mg)  Nominal  
Value  
(carats)  Maintenance  
Tolerance 
(mg)  
1 
2 
3 
5 
10 
20 
 250 
400 
500 
800 
   1000  
 1500  0.25*  
0.5** 1.0 
2.0 
3.0 
5.0 
10.0 
20.0 
30.0 
50.0 
100.0  0.6 
1.0 
1.5 
2.0 
3.0 
4.0 
6.0 
10.0 
12.0 
15.0 
25.0 
  *25 points or less  
**50 points   
 
T.5. On Apothecaries and Troy Weights.  – The maintenance tolerances shall be as shown in Table 3. 
Maintenance Tolerances for Apothecaries’ and Troy Weights.  Acceptance tolerances shall be one -half the 
maintenance tolerances.  
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 Table 3.  
Maintenance Tolerances  for Apothecaries’ and Troy Weights  
Nominal  
Value  Maintenance Tolerance Nominal  
Value  Maintenance Tolerance 
grains  grains  mg oz grains  mg 
1 
2 
3 
5 
10 
20 0.01 
0.02 
0.03 
0.03 
0.04 
0.06 0.6 
1.3 
2.0 
2.0 
2.5 
4.0 1 
2 
3 
4 
5 0.4 
0.6 
1.0 
1.5 
1.6 25.0 
40.0 
65.0 
100.0  
105.0  
scruples  grains  mg oz grains  mg 
1 
2 0.06 
0.10 4.0 
6.5 6 
7 
8 
9 
10 1.8 
1.9 
2.0 
2.1 
2.2 115.0  
125.0  
130.0  
135.0  
145.0  
dr grains  mg oz grains  mg 
0.5 
1.0 
2.0 
3.0 
4.0 
5.0 
6.0 0.07 
0.10 
0.20 
0.30 
0.40 
0.50 
0.60 4.5 
6.5 
13.0 
20.0 
25.0 
30.0 
40.0 11 
12 
20 
30 
50 2.4 
2.5 
2.9 
3.7 
5.4 155.0  
160.0  
190.0  
240.0  
350.0  
dwt grains  mg oz grains  mg 
1 
2 
3 
4 
5 
10 0.06 
0.10 
0.15 
0.20 
0.30 
0.40 4.0 
6.5 
10.0 
13.0 
20.0 
25.0 100 
200 
300 
500 
1 000  7.7 
12.3 
15.4 
23.1 
38.6 500.0  
800.0  
1 000.0  
1 500.0  
2 500.0  
 
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                                                                                                                                                            Agency No.209.02  
 Section 2.24.  Automatic Weighing Systems  
 
 
A. Application  
 
A.1. General.  – This code applies to devices used to automatically weigh pre -assembled discrete loads or single 
loads or loose materials in applications where automatic weighing systems35 are used or employed in the 
determination of quantities, things, prod uce, or articles for distribution, for purchase, offered or submitted for sale, 
for distribution, purchase, or in computing any basic charge or payment for services rendered on the basis of weight, and in packaging plants subject to regulation by the USDA.   Some weigh -labelers and checkweighers may also 
include a scale that is incorporated in a conveyor system that weighs packages in a static or non -automatic weighing 
mode
36. 
 This includes:  
 
(a) Automatic weigh -labelers;  
 
(b) Combination automatic and non -automatic  weigh -labelers;  
 
(c) Automatic checkweighers;  
 
(d) Combination automatic and non -automatic checkweighers; and  
 
(e) Automatic gravimetric filling machines that weigh discrete loads or single loads of loose materials and 
determine package and production lot compliance with net content representations.  
(Amended 1997 and 2004)  
 A.2. Exceptions.  - This code does not apply to:  
 
(a) Belt- Conveyor Scale Systems;  
 
(b) Railway Track Scales;  
 
(c) Monorail Scales ; 
 
(d) Automatic Bulk -Weighing Systems;  
                                                           
35 An automatic weighing system does not require the intervention of an operator during the weighing process.  
The necessity to give  instructions to start a process or to release a load or the function of the instrument (static, 
dynamic, set -up, etc.) is not relevant in deciding the category of automatic or non- automatic instruments.  
(Added 2004)  
 
36 Prepackaging scales (and other commercial devices) used for putting up packages in advance of sale are 
acceptable for use in commerce if all appropriate provisions of Handbook 44 are met.  Users of such devices must 
be alert to the legal requirements relating to the declaration of quant ity on a package.  Such requirements are to 
the effect that, on the average, the contents of the individual packages of a particular commodity comprising a lot, 
shipment, or delivery must contain at least the quantity declared on the label.  The fact that a scale or other 
commercial device may overregister, but within established tolerances, and is approved for commercial service is 
not a legal justification for packages to contain, on the average, less than the labeled quantity.  
(Added 2004)  2.24.  Automatic Weighing Systems   Handbook 44 –  20152016  
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(e) Devices that measure quantity on a time basis;  
 
(f) Controllers or other auxiliary devices except as they may affect the weighing performance; or  
 
(g) Automatic gravimetric filling machines and other automatic weighing systems employed in determining the 
weight of a commodity in a plant or business with a separate quantity control program (e.g., a system of 
statistical process control) using suitable weighing instruments and measurement standards traceable to 
national standards to determine production lot compliance with net co ntent representations.37 
(Added 2004)  
 
A.3. Additional Code Requirements . – In addition to the requirements of this code, Automatic Weighing 
Systems shall meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Zero Indication.  
 
(a) A weigh -labeler  shall be equipped with an indicating or recording element.  Additionally, a 
weigh -labeler  equipped with an indicating or recording  element shall either indicate or record a 
zero-balance condition and an out -of-balance condition on both sides of zero.  
(Amended 2004)  
 
(b) An automatic checkweigher  may be equipped with an indicating or recording element.  
 
(c) A zero -balance condition may be indicated by other than a continuous digital zero indication, provided 
that effective automatic means is provided to inhibit a weighing operation or to return to a continuous 
digital indication when the device is in an out -of-balance condition.  
 
S.1.1.1.  Digital Indica ting Elements.  
 
(a) A digital zero indication shall represent a balance condition that is within ±  ½ scale division.  
 
(b) A digital indicating device shall either automatically maintain a “center of zero” condition to 
± ¼ scale division or less, or have an  auxiliary or supplemental “center -of-zero” indicator that 
defines a zero -balance condition to ±  ¼ scale division or less.  
 
(c) Verification of the accuracy of the center of zero indication to ±  ¼ scale division or less during 
automatic operation is not requir ed on automatic checkweighers . 
(Amended 2004)  
 
                                                           
37 See NIST Han dbook 130, “Uniform Laws and Regulations in the Area of Legal Metrology and Engine Fuel 
Quality ,,” Interpretations and Guidelines, paragraph 2.6.11. Good Quantity Control Practices.  Handbook 44 –  20152016   2.24.  Automatic Weighing Systems  
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                                                                                                                                                            Agency No.209.02  
 S.1.2.  Value of Division Units.  – The value of a division d expressed in a unit of weight shall be equal 
to: 
 
(a) 1, 2, or  5; or 
 (b) a decimal multiple or submultiple of 1, 2, or  5. 
 
The requirement that the value of the scale division be expressed only as 1, 2, or  5, or a decimal multiple or 
submultiple of only 1, 2, or  5 does not apply to net weight indications and recorded representations that are 
calculated from gross and tare weight indications where the scale division of the gross weight is different from 
the scale division of the tare weight(s) on multi -interval or multiple range scales.  For example, a multiple range 
or multi -interval scale may indicate and record tare weights in a lower weighing range (WR) or weighing 
segment (WS), gross weights in the higher weighing range or weighing segment, and net weights as follows:  
 
55 kg Gross Weight (WR2  d = 5  kg) 10.05  lb Gross Weight (WS2 d = 0.05  lb) 
– 4 kg Tare Weight   (WR1  d = 2  kg) – 0.06 lb Tare Weight   (WS1 d = 0.02  lb) 
= 51 kg Net Weight     (Mathematically Correct)  = 9.99  lb Net Weight     (Mathematically Correct)  
(Amended 2008)  
 
S.1.2.1.  Weight Units.  – Except for postal scales, indicating and recording elements for shipping and 
postal applications, and scales used to print standard pack labels, a device shall indicate weight values 
using only a single unit of measure.  
(Amended 2004)  
 
S.1.3.  Provision for Sealing.  
 
(a) Automatic Weighing Systems, Except Automatic Checkweighers. – A device shall be designed 
with provision(s) as specified in Table  S.1.3. Categories of Device and Methods of Sealing for 
applying a security seal that must be broken, or for using other approved means of providing security 
(e.g., data change audit trail  available at the time of inspection), before any change that detrimentally 
affects the metrological integrity of the device can be made to any electronic mechanism.  
 
(b) For Automatic Checkweighers. –  Security seals are not required in applications where it would 
prohibit an authorized user from having access to the calibration functions of a device.  
 
Table S.1.3.  
Categories of Device and Methods of Sealing 
Categories of Device  Methods of Sealing  
Category  1:  No Remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for configuration 
parameters.  
Category  2:  Remote configuration capability, but 
access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the 
remote configuration mode and record such message 
if capable of printing in this mode.  The hardware enabling access for remote 
communication must be at the device and sealed using 
a physical seal or two event counters:  one for 
calibration parameter s and one for configuration 
parameters.  2.24.  Automatic Weighing Systems   Handbook 44 –  20152016  
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 Category  3:  Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password). An event logger is required in the device; it must 
include an event counter (000  to 999), the parameter 
ID, the date and time of the change, and the new value 
of the parameter.  A printed copy of the information 
must be available through the device or through 
another on -site device.  The event logger shall have a 
capacity to retain records eq ual to 10 times the 
number of sealable parameters in the device, but not 
more than 1 0001000 records are required.  ( Note:   
Does not require 1 0001000 changes to be stored for 
each parameter. ) 
 
S.1.4.  Automatic Calibration.  – A device may be fitted with an automatic or a semi -automatic 
calibration mechanism.  This mechanism shall be incorporated inside  the device.  After sealing, neither the 
mechanism nor the calibration process shall facilitate fraud.  
 
S.1.5.  Adjustable  Components.  – Adjustable components shall be held securely in adjustment and, 
except for a zero -load balance mechanism, shall be located within the housing of the element.  
 
S.2. Design of Zero and Tare Mechanisms.  
 
S.2.1.  Zero Load Adjustment.  
 
S.2.1.1.  Automatic Zero -Tracking Mechanism. –  Except for automatic checkweighers , under normal 
operating conditions the maximum load that can be “ rezeroed ,” when either placed on or removed from the 
platform all at once, shall be 1.0  scale division.  
 
Except for an initial zero -setting mechanism, an automatic zero adjustment outside these limits is 
prohibited.  
(Amended 2004 and 2010)  
 
S.2.1.2.  Initial Zero -Setting Mechanism. –  Except for automatic checkweighers , an initial zero -setting 
mechanism shall not zero a load  in excess of 20  % of the maximum capacity of the automatic weighing 
system unless tests show that the scale meets all applicable tolerances for any amount of initial load compensated by this device within the specified range.  
 
S.2.2.  Tare.  – On any automa tic weighing system (except for multi -interval scales or multiple range 
scales when the value of tare is determined in a lower weighing range or weighing segment) the value of the 
tare division shall be equal to the value of the scale division.  The tare m echanism shall operate only in a 
backward direction (i.e., in a direction of underregistration ) with respect to the zero -load balance condition of 
the automatic weighing system.  A device designed to automatically clear any tare value shall also be designed 
to prevent the automatic clearing of tare until a complete transaction has been indicated.  
(Amended 2008)  
 
Note:   On a computing automatic weighing system, this requires the input of a unit price, the display of the unit price, and a 
computed positive total price at a readable equilibrium.  Other devices require that a transaction or lot run be completed.  
(Note Amen ded 2004)  
 
S.3. Verification Scale Interval.  
 
S.3.1.  Multiple Range and Multi -Interval Automatic Weighing System.  – The value of  e shall be 
equal to the value of  d. 
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 Ndv≤minS.3.2.  Load Cell Verification Interval Value.  – The relationship of the value for the load cell 
verification scale interval, v min, to the scale division  d for a specific scale installation shall be:  
 
             , where N is the number of load cells in the scale.  
 
Note:   When the value of the scale division d differs from the verification scale division e for the scale, the value of  e must 
be used in the formula above.  
 
S.3.3. – For automatic checkweighers , the value of  e shall be specified by the manufacturer and may be larger 
than d, but in no case can  e be more than ten times the value of  d. 
 
S.4. Weight Indicators, Weight Displays, Reports, and Labels.  
 
S.4.1.  Additional Digits in Displays.  – Auxiliary digital displays that provide additional digits for use 
during performance evaluation  may be included on automatic checkweighers .  However, in cases where these 
indications are not valid for determining the actual weight of a package (e.g., onl y appropriate for use in 
statistical process control programs by users) they shall be clearly and distinctly differentiated from valid 
weight displays by indicating them to the user.  
 For example, the additional digits may be differentiated by color, partially covered by placing crosshatch 
overlays on the display, or made visible only after the operator presses a button or turns a key to set the device in a mode which enables the additional digits.  
 S.4.2.  Damping.  – An indicating element equipped with othe r than automatic recording elements shall 
be equipped with effective means to permit the recording of weight values only when the indication is stable 
within plus or minus one scale division.  The values recorded shall be within applicable tolerances.  
 S.4.3. Over Capacity Indication.  – An indicating or recording element shall not display nor record any 
values when the scale capacity is exceeded by nine scale divisions.  
 
S.4.4.  Label Printer.  – A device that produces a printed ticket to be used as the label  for a package shall 
print all values digitally and of such size, style of type, and color as to be clear and conspicuous on the label.  
 
S.4.4.1.  Label Printing. – If an automatic checkweigher prints a label containing weight information 
that will be used in a commercial transaction, it must conform to all of the requirements specified for weigh -labelers so that the printed ticket meets appropriate requirements.  
 
S.5. Accuracy Class.  
 
S.5.1.  Marking.  – Weigh- labelers and automatic checkweighers shall be Class III devices and shall be 
marked accordingly, except that a weigh -labeler marked Class  IIIS may be used in package shipping 
applications.  
(Amended 1997)  
 
S.6. Parameters for Accuracy Classes.  – The number of divisions for device capacity is designated  by the 
manufacturer and shall comply with parameters shown in Table S.6. Parameters for Accuracy Classes.  
  
 
 
 
Table S.6.  
Parameters for Accuracy Classes  
 Number of Divisions (n)  2.24.  Automatic Weighing Systems   Handbook 44 –  20152016  
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 Class  Value of the Verification Division (e)  Minimum  Maximum  
      SI Units  
III 0.1 to 2 g, inclusive  100 10 000 
equal to or greater than 5 g  500 10 000 
     U.S. Customary  Units  
III 0.0002 lb to 0.005 lb, inclusive  100 10 000 
0.005 oz to 0.125 oz, inclusive  100 10 000 
equal to or greater than 0.01 lb  500 10 000 
equal to or greater than 0.25 oz  500 10 000 
IIIS greater than 0.01 lb  100   1 000 
greater than 0.25 oz  100   1 000 
For Class  III devices, the value of  e is specified by the manufacturer as marked on the device; d shall not be 
smaller than 0.1  e.  e shall be differentiated from d by size, shape, or color.  
(Amended 2004)  
 S.7. Marking Requirements.   [Also see G -S.1. Identification, G -S.4. Interchange or Reversal of Parts, 
G-S.6. Marking Operational Controls, Indications, and Features, G -S.7. Lettering, G -UR.2.1.1. Visibility of 
Identification, and UR.3.3.  Special Designs]  
 
S.7.1.  Location of Marking Information.  – Automatic weighing systems which are not permanently 
attached to an indicating element, and for which the load -receiving eleme nt is the only part of the 
weighing/load -receiving element visible after installation, may have the marking information required in 
Section 1.10.  General Code, G-S.1. Identification  of the General Code,  and Section 2.24. Automatic Weighing 
Systems Code, Table S.7.a. Marking Requirements and Table  S.7.b. Notes for Table  S.7.a. of the Automatic 
Weighing Systems Code  located in an area that is accessible only through the use of a tool; provided that the 
information is easily accessible (e.g., the information may appear on the junction box under an access plate).  
The identification information for these automatic weighing systems shall be located on the weighbridge (load -
receiving element) near the point where the signal leaves the weighing element, or beneath  the nearest access 
cover.  Handbook 44 –  20152016   2.24.  Automatic Weighing Systems  
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                                                                                                                                                            Agency No.209.02  
 Table S.7.a. Marking Requirements  
 
To Be  
Marked With  ⇓ Weighing Equipment  
Weighing, load -
receiving, and 
indicating element 
in same housing  Indicating element 
not permanently 
attached to 
weighing and 
load-receiving 
element  Weighing and 
load-receiving 
element not 
permanently 
attached to 
indicating element  Load 
cell 
with 
CC 
(10) Other 
equipment 
or device 
(9) 
Manufacturer’s ID  
 (1) x  x x x  x 
Model Designation  
 (1) x  x x x  x 
Serial Number and Prefix  (2)  x  x x x  x (13)  
Certificate of Conformance 
(CC) Number        
(16) x  x x x  x (16)  
Accuracy Class        
(14) x  x (8)  x x  
Nominal Capacity
 (3)(15)  x  x x   
Value of Division, d  
 (3) x  x    
Value of e   
  (4) x  x    
Temperature Limits  
 (5) x  x x x  
Special Application       
(11) x  x x   
Maximum Number of  
Scale Divisions, n max        
(6)   x (8)  x x  
Minimum Verification  
Division, (e min)   x   
“S” or “M”   
  (7)    x  
Direction of Loading       
(12)    x  
Minimum Dead Load     x  
Maximum Capacity (Max)  x   x  
Minimum Capacity (Min ) x     
Safe Load Limit     x  
Load Cell Verification  
Interval (v min)    x  
Maximum Belt Speed  
(m/sec or m/min)  x  x   
Note:   Also see Table  S.7.b. for applicable parenthetical notes.  
 (Amended 1999)  
 2.24.  Automatic Weighing Systems   Handbook 44 –  20152016  
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 Table S.7.b.  
Notes for Table S.7.a.  
1. Manufacturer’s identification and model designation.  (Also s ee G-S.1. Identification)  
 
2. Serial number and prefix.  Also see G -S.1. Identification)  
 
3. The nominal capacity and value of the automatic weighing system division shall be shown together (e.g., 50 000 × 5 kg, or 30  × 0.01 lb
) adjacent to the weight display when the nominal capacity and value of the 
automatic weighing system division are not immediately apparent.  Each division value or weight unit shall be 
marked on variable -division va lue or division -unit automatic weighing systems.  
 
4. Required only if different from  d. 
 
5. Required only on automatic weighing systems if the temperature range on the NTEP CC is narrower than and within 
– 10 ºC to 40 ºC (14  ºF to 104  ºF). 
(Amended 2007)  
 
6. This value may be stated on load cells in units of 1000; (e.g., n max 10 is 10 000 divisions.)  
 
7. Denotes compliance for single or multiple load cell applications.  
 
8. An indicating element not permanently attached to a weighing element shall be clearly and perm anently marked with 
the accuracy Class  III, or IIIS and the maximum number of divisions,  nmax. 
 
9. Necessary to the weighing system but having no metrological effect (e.g.,  auxiliary remote display, keyboard, etc.).  
 
10. The markings may be either on the load cell or in an accompanying document; except that, if an accompanying 
document is provided, the serial number shall appear both on the load cell and in the document.  The manufacturer’s 
name or trademark, the model designation, and identifying symbol for th e serial number shall also be marked both on 
the load cell and in any accompanying document.  
 
11. An automatic weighing system designed for a special application rather than general use shall be conspicuously 
marked with suitable words visible to the operator and customer restricting its use to  that application.  
 
12. Required if the direction of loading the load cell is not obvious.  
 
13. Serial number and prefix (Also see G -S.1. Identification) modules without “intelligence” on a modular system 
(e.g., printer, keyboard  module, cash drawer, and secondary display in a point -of-sale system) are not required to 
have serial numbers.  
 
14. The accuracy class of a device shall be marked on the device with the appropriate designation.  
 
15. The nominal capacity shall be conspicuously mar ked on any automatic -indicating or recording automatic weighing 
system so constructed that the capacity of the indicating or recording element, or elements, is not immediately apparent.  
 
16. Required  only if a CC has been issued for the equipment.  
 Handbook 44 –  20152016   2.24.  Automatic Weighing Systems  
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 S.7.2.  Marking Required on Components of Automatic Weighing Systems.  – The following 
components of automatic weighing systems shall be marked as specified in Tables  S.7.a. Marking Requirements 
and S.7.b.  Notes for Table S.7.2.a.:  
 
(a) Main elements and components  when not contained in a single enclosure for the entire automatic weighing 
system;  
 
(b) Load cells for which Certificates of Conformance (CC) have been issued under the National Type 
Evaluation Program; and  
 
(c) Other equipment necessary to  a weighing system but having no metrological effect on the weighing 
system.  
 
N. Notes  
 
N.1. Test Requirements for Automatic Weighing Systems.  
 
N.1.1.  Test Pucks and Packages.  
 
(a) Test pucks  and packages shall be:  
 
(1) representative of the type, size, and weight ranges to be weighed on a device; and  
 
(2) stable  while in motion, hence the length and width of a puck or package should be greater than its 
height.  
 
(b) For type evaluation the manufacturer shall supply the test pucks  or pa ckages for each range of test 
loads.  
(Amended 1997)  
 
N.1.2.  Accuracy of Test Pucks or Packages.  – The error in any test puck or package shall not exceed 
one-fourth  (¼) of the acceptance tolerance.  If packages are used to conduct field tests on automatic w eighing 
systems, the package weights shall be determined on a reference scale or balance with an inaccuracy that does not exceed one -fifth (
1/5) of the smallest tolerance that can be applied to the device under test.  
 
N.1.3.  Verification (Testing) Standards.  – Field standard weights shall comply with requirements  of 
NIST Handbook  105-1, “Specifications and Tolerances for Field Standard Weights  (Class  F))” or the tolerances 
expressed in Fundamental Considerations, paragraph  3.2.  (i.e., one-third of the smallest tolerance applied).  
 
N.1.4.  Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility, 
Field Evaluation.  – An RFI test shall be conducted at a given installation when the presence of RFI has been 
verified and characterized if those conditions are considered “usual and customary.”  
(Added 2004)  
 
N.1.5.  Tests Loads.  – A performance test shall consist of four separate test runs conducted at different 
test loads according to Table  N.1.5. Test Loads.  
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 Table N.1.5.  
Test Loads  
At or near minimum capacity  
At or near maximum capacity  
At two  (2) critical points between minimum and maximum capacity  
Test may be conducted at other loads if the device is intended for use at other specific capacities  
 
N.1.6.  Influence Factor Testing.  – Influence factor testing shall be conducted statically.  
 
N.2. Test Procedures -  Weigh -Labelers.  – If the device is designed for use in a non- automatic weighing mode, it 
shall be tested in the non -automatic mode according to NIST Handbook  44, Section  2.20. Scales Code.  
 
Note:   If the device is designed for only automatic weighing, it shall only be tested in the automatic weighing mode.  
(Amended 2004)  
 
N.2.1.  Non-Automatic Tests.  
 
N.2.1.1.  Increasing -Load Test. – The increasing -load test shall be conducted with the test loads 
approximately centered on the load -receiving element of the scale.  
 
N.2.1.2.  Decreasing -Load Test. –  The decreasing -load test shall be conducted with the test loads 
approximately centered on the load -receiving element  of the scale.  
 
N.2.1.3.  Shift Test. –  To determine the effect of off -center loading, a test load equal to one -half (½) 
maximum capacity shall be placed in the center of each of the four points equidistant between the center 
and front, left, back, and right edges of the load receiver.  
 N.2.1.4.  Discrimination Test. – A discrimination test shall be conducted with the weighing device in 
equilibrium at zero -load and at maximum test load, and under controlled conditions in which environmental 
factors are reduced to the extent that they will not affect the results obtained.  This test is conducted from just below the lower edge of the zone of uncertainty for increasing -load tests, or from just above the upper 
edge of the zone of uncertainty for decreasing -load tests.  
 N.2.1.5.  Zero -Load Balance Change. –  A zero -load balance change test shall be conducted on all 
automatic weighing systems after the removal of any test load.  The zero -load balance should not change 
by more than the minimum tolerance applicable .  (Also see G -UR.4.2. Abnormal Performance)  
(Amended 2004)  
 
N.2.2.  Automatic Test Procedures.  
 
N.2.2.1.  Tests  Non-Automatic. – If the automatic weighing system is designed to operate 
non-automatically, and is used in that manner, during normal use operation, it shall be tested 
non-automatically using mass standards.  The device shall not be tested non -automatically if it is used only 
in the automatic mode.  
 
N.2.2.2.  Automatic Tests. –  The device shall be tested at the normal operating speed using packages.  
Test runs should be conducted using at least two test loads  distributed over its normal weighing range 
(e.g.,  near the lowest and highest ranges in which the device is typically o perated.)  Each test load should 
be run a minimum of ten consecutive times.  
(Amended 2004)  
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 N.3. Test Procedures -  Automatic Checkweigher.  
 
N.3.1.  Tests Non -Automatic.  – If the scale is designed to operate non -automatically during normal user 
operation, it shall be tested non -automatically according to paragraphs  N.2.1.1. Increasing Load Test through 
N.2.1.5. Zero -Balance Change.  
(Amended 2004)  
 
N.3.2.  Automatic Tests.  – The device shall be tested at the highest speed in each weight range using 
standardized  test pucks or packages.  Test runs shall be conducted using two test loads.  The number of 
consecutive test weighments shall be as specified in Table  N.3.2. Number of Sample Weights per Test for 
Automatic Checkweighers.  
(Amended  2004)  
 
Table N.3.2.   
Number of Sample Weights per Test for Automatic Checkweighers  
Weighing Range  
m = mass of test load  Number of Sample Weights per Test  
Field  Type 
Evaluation  
20 divisions < m < 10 kg  
20 divisions <  m < 22 lb  30 60 
10 kg < m < 25 kg  
22 lb < m <  55 lb  16 32 
25 kg < m < 100 kg  
55 lb < m <  220 lb  10 20 
100 kg (220 lb) < m  10 10 
 
T. Tolerances  
 
T.1. Principles.  
 
T.1.1.  Design.  – The tolerance for a weighing device is a performance requirement independent of the 
design principle used.  
 
T.1.2.  Scale Division.  – The tolerance for a weighing device is related to the value of the scale 
division  (d) or the value of the verification scale division  (e) and is generally expressed in terms of  d or e.  The 
random tolerance for automatic checkweighers is expres sed in terms of Maximum Allowable Variance (MAV).  
 
T.2. Tolerance Application.  
 
T.2.1.  General.  – The tolerance values are positive (+) and negative  (−) with the weighing device 
adjusted to zero at no load.  When tare is in use, the tolerance values are ap plied from the tare zero reference 
(zero net weight indication); the tolerance values apply to the net weight indication for any possible tare load 
using certified test loads.  
(Amended 2008)  
 T.2.2.  Type Evaluation Examinations.  – For type evaluation examinations, the tolerance values apply 
to increasing and decreasing load tests within the temperature and power supply limits specified in T.7. Influence Factors.  
(Amended  2004)  
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 T.2.3.  Subsequent Verification Examinations.  – For subsequent verification examinations, the 
tolerance values apply regardless of the influence factors in effect at the time of the conduct of the examination.  
(Also see G -N.2. Testing with Nonassociated Equipment ).) 
(Added 2007)  
 T.2.4.  Multiple Ran ge and Multi -Interval Automatic Weighing System.  – For multiple range and 
multi -interval devices, the tolerance values are based on the value of the scale division of the range in use.  
 
T.3. Tolerance Values.  
 
Table T.3.  
Class III - Tolerance in Divisions  (e) 
Test Load in Divisions  Tolerance in Divisions  
Class III  Acceptance  Maintenance  
0 - 500 ± 0.5  ± 1 
501 - 2000  ± 1.0  ± 2 
2001 - 4000  ± 1.5  ± 3 
4001 +  ± 2.5  ± 5 
 
T.3.1.  Tolerance Values –  Class III Weigh -Labeler.   (Also see Section  T.3.2. Class IIIS 
Weigh -Labelers ).) 
 
T.3.1.1.  Non-automatic  Tests.  – Tolerance values shall be as specified in 
Table  T.3. Class III - Tolerance in Divisions  (e). 
(Amended 2004)  
 
T.3.1.2.  Automatic Tests.  – Acceptance tolerance values shall be the same as maintena nce tolerance 
values specified in Table T.3. Class  III - Tolerance in Divisions  (e). 
(Amended 2004)  
 
T.3.2.  Tolerance Values -  Class IIIS Weigh -labelers in Package Shipping Applications.  
(Added 1997)  
 
T.3.2.1.  Non-automatic Tests.  – Tolerance values shall be as specified in Table T.3.2.1. Non-automatic 
Tolerances for Class IIIS Weigh -labelers.  
(Amended 2004)  
 
T.3.2.2.  Automatic Tests. –  Tolerance values specified in  Table  T.3.2.2.  Automatic Tolerances for 
Class  IIIS Weigh -labelers shall be applied.  
(Amended 2004)  
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 Table T.3.2.1.  
Non-automatic Tolerances  
for Class  IIIS Weigh -labelers   Table T.3.2.2.  
Automatic Tolerances  
for Class  IIIS Weigh -labelers  
Test Load in 
Divisions  Tolerance in Divisions   Test Load in 
Divisions  Tolerance in  Divisions  
Class IIIS  Acceptance  Maintenance   Class IIIS  Acceptance  Maintenance  
0 - 50 ± 0.5  ± 1  0 - 50 ± 1.5  ± 2 
51 - 200 ± 1.0  ± 2  51 - 200 ± 2.0  ± 3 
201 - 1000  ± 1.5  ± 3  201 - 1000  ± 2.5  ± 4 
(Added 1997) (Amended 2004)   (Added 1997) (Amended 2004)  
 
T.3.3.  Tolerance Values.  – Automatic Checkweighers.  
 
T.3.3.1.  Laboratory Tests for Automatic Checkweighers.  
 
T.3.3.1.1.  Non-Automatic  Tests.  – The acceptance tolerance values specified in 
Table  T.3. Class III - Tolerance in Divisions  (e), shall be applied.  
(Amended 2004)  
 
T.3.3.1.2.  Automatic Tests.  
 
(a) The systematic error for each test run shall be within the acceptance tolerances specified in 
Table  T.3. Class III - Tolerance in Divisions  (e) for the test loads specified in 
Table  N.1.5.  Test Loads.  
(Amended 2004)  
 
(b) The standard deviation of the results shall not exceed one- ninth (1/9) of the MAV for specific 
package weights (which means that three standard deviations cannot exceed one- third  (1/3) of 
the MAV value) as required in the latest edition of NIST Handbook  133, “Checking the Net 
Contents of Packaged Goods.”   This value does not change regardless of whether acceptance 
or maintenance tolerances are being applied to the device under test.  
(Amended 2004)  
 
(1) For U.S. Department of Agriculture (USD A) inspected meat and poultry products 
packaged at a plant subject to inspection by the USDA Food Safety and Inspection 
Service, use NIST Handbook  133, Appendix A. Tables,  Table  2-9, U.S. Department of 
Agriculture, Meat and Poultry, Groups and Lower Limits  for Individual Packages;  
 
(2) for all other packages with a labeled net quantity in terms of weight, use NIST 
Handbook  133, Appendix A. Tables,  Table  2-5, Maximum Allowable Variations  (MAVs)  
for Packages Labeled by Weight; or  
 
(3) for all packages with a labeled net quantity in terms of liquid or dry volume use NIST 
Handbook  133, Appendix A. Tables,  Table  2-6, Maximum Allowable Variations  (MAVs)  
for Packages Labeled by Liquid or Dry Volume.  
(Amended 2004)  
 
T.3.3.2.  Field Tests for Automatic Checkweighers.  
 
T.3.3.2.1.  Non-Automatic  Test.  – The tolerance values shall be as specified in 
Table  T.3. Class III – Tolerance in Divisions  (e). 
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T.3.3.2.2.  Automatic Test.  
 
(a) The systematic error requirement is not applied in a field test.  
 
(b) The standard deviation of the test results shall not exceed one -ninth (1/9) of the MAV for 
specific package weights (which means that three standard deviations cannot exceed 
one-third  (1/3) of the MAV value) as required in the latest Edition of NIST Handbook  133.  
This value does not change regardless of whether acceptance or maintenance tolerances are 
being applied to the device under test.  
(Amended 2004)  
 
(1) For USDA inspected meat and poultry products packaged at a plant subject to inspection by the USDA Food Safety  and Inspection Service, use NIST Handbook  133, Appendix 
A, Tables,  Table  2-9, U.S. Department of Agriculture, Meat and Poultry, Groups and 
Lower Limits for Individual Packages;  
 
(2) for all other packages with a labeled net quantity in terms of weight, us e NIST 
Handbook  133, Appendix A. Tables,  Table  2-5, Maximum Allowable Variations  (MAVs)  
for Packages Labeled by Weight; or  
 
(3) for all packages with a labeled net quantity in terms of liquid or dry volume use NIST 
Handbook  133, Appendix A. Tables,  Table  2-6. Maximum Allowable Variations  (MAVs)  
for Packages Labeled by Liquid or Dry Volume.  
 
T.4. Agreement of Indications.  – In the case of a weighing system equipped with more than one indicating 
element or indicating element and recording element combination,  the difference in the weight value indications of 
any load shall not be greater than the absolute value of the applicable tolerance for that load, and shall be within tolerance limits.  
 
T.5. Repeatability.  – The results obtained from several weighings of the same load under reasonably constant test 
conditions shall agree within the absolute value of the maintenance tolerance for that load, and shall be within 
applicable tolerances.  
(Amended 2004)  
 
T.6. Discrimination.  – A test load equivalent to 1.4  d shall cause a change in the indicated or recorded value of at 
least 2.0  d.  This requires the zone of uncertainty to be not greater than 0.3  d (See N.2.1.4. Discrimination Test).  
(Amended 2004)  
 T.7. Influence Factors.  – The following factors are applicable to tests conducted under controlled conditions 
only.  
 
T.7.1.  Temperature.  – Devices shall satisfy the tolerance requirements under the following temperature 
conditions:  
 
T.7.1.1.  if not specified in the operating instru ctions or if not marked on the device, the temperature limits 
shall be:  −  10 °C to 40 °C (14  °F to 104 °F). 
 
T.7.1.2.  if temperature limits are specified for the device, the range shall be at least 30  °C (54  °F). 
 
T.7.1.3.  Temperature Effect on Zero -Load Balance.  – The zero -load indication shall not vary by more 
than one division per 5  °C (9 °F) change in temperature.  
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 T.7.1.4.  Operating Temperature.  – The indicating or recording element shall not display nor record 
any usable values until the operating temperature necessary for accurate weighing and a stable zero balance 
condition have been attained.  
 
T.7.2.  Electric Power Supply.  
 
T.7.2.1.  Range of Voltages.  
 
(a) Automatic weighing systems that operate using alternating current must perform within the 
conditions defined in paragraphs  T.3. Tolerance Values through T.6 .,. Discrimination,  inclusive, 
when tested over the range of −  15 % to +  10  % of the  marked nominal line voltage(s) at 60  Hz, 
or the voltage range marked by the manufacturer, at 60  Hz. 
 
(b) Automatic weighing systems that operate using DC current must perform within the conditions 
defined in paragraphs  T.3. Tolerance Values through T.6., . Discrimination,  inclusive, when tested 
over the range from  minimum operating voltage38 to + 20 % of the voltage marked on the 
instrument (nominal voltage).  
 (c) Battery -operated electronic automatic weighing systems with external or plug -in power supply 
(AC or DC) shall either continue to function correctly or not indicate any weight values if the voltage is below the manufacturer’s specified value, the latter being larger than or equal to the 
minimum operating voltage.
4 
 Note:   This requirement applies only to metrologically significant voltage supplies.  
(Amended 2001)  
(Amended 2004)  
 
T.7.2.2.  Power Interruption. –  A power interruption shall not cause an indicating or recording element 
to display or record any values outside the applicable tolerance limits.  
 
T.8. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility.  – The 
differen ce between the weight indication with the disturbance and the weight indication without the disturbance 
(also see N.1.4. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility, Field 
Evaluation) shall not exceed one scale division  (d) or the equipment shall:  
 
(a) blank the indication;  
 
(b) provide an error message; or  
 
(c) the indication shall be so completely unstable that it could not be interpreted, or transmitted into memory or 
to a recording element, as a correct measurement value.  
(Amended 2004)  
 
                                                           
38 The minimum operating voltage is defined as the lowest possible operating voltage before the automatic 
weighing system no longer indicates nor records weight values.  
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 UR. User Requirements  
 
UR.1.  Selection Requirements.  – Equipment shall be suitable for the service in which it is used with respect to 
elements of its design, including but not limited to, its capacity, number of scale divisions, value of the scale 
division or verification scale division, minimum capacity, and computing capability.  
 
UR.1.1.  General.  – Automatic Weighing Systems shall be designated by the manufacturer for that service.  
 
UR.1.2.  Value of the Indicated and Recorded Scale Division.  – The value of the division as recorded shall 
be the same as the division value indicated.  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Protection from Environmental Factors.  – The indicating elements, the lever system or load cells, 
and the load -receiving element of a permanently installed scale, and the indicating elements of a scale not 
intended to be permanently installed, shall be adequately protected from environmental f actors such as wind, 
weather, and RFI that may adversely affect the operation or performance of the device.  
 
UR.2.2.  Foundation, Supports, and Clearance.  – The foundation and supports of any scale installed in a 
fixed location shall be such as to provide s trength, rigidity, and permanence of all components, and clearance 
shall be provided around all live parts to the extent that no contacts may result when the load -receiving element 
is empty, nor throughout the weighing range of the scale.  
 
UR.2.3.  Entry an d Departure from Weighing Area.  – The belt or other conveyance that introduces the 
weighed load to the weighing zone and that carries the weighed load away from the weighing zone shall be 
maintained per the manufacturer’s recommendations.  
 
UR.3.  Use Requir ements.  
 
UR.3.1.  Minimum Load.  – The minimum load shall be as specified by the manufacturer, but not less than 
twenty divisions since the use of a device to weigh light loads is likely to result in relatively large errors.  
 
UR.3.1.1.  Minimum Load for Class IIIS Weigh -Labelers. – The minimum load shall be as 
specified by the manufacturer, but not less than ten divisions since the use of a device to weigh light loads 
is likely to result in relatively large errors.  
(Added 1997)  
 
UR.3.2.  Maximum Load.  – An automatic weighing system shall not be used to weigh a load of more than its 
maximum capacity.  
(Amended 2004)  
 UR.3.3.  Special Designs.  – An automatic weighing system designed and marked for a special application 
shall not be used for oth er than its intended purpose.  
 
UR.3.4.  Use of Manual Gross Weight Entries.  – Manual entries are permitted only when a device or 
system is generating labels for standard weight packages.  
 
UR.4.  Maintenance Requirements.  
 
UR.4.1.  Balance Condition.  – If an automatic weighing system is equipped with a zero -load display, the 
zero-load adjustment of an automatic weighing system shall be maintained so that the device indicates or 
records a zero balance condition.  
 
UR.4.2.  Level Condition.  – If an automa tic weighing system is equipped with a level -condition indicator, 
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UR.4.3.  Automatic Weighing System Modification.  – The length or the width of the load -receiving 
element of an automatic weighing system shall not be increased beyond the manufacturer’s design dimension, 
nor shall the capacity of an automatic weighing system be increased beyond its design capacity by replacing or 
modifying the original primary indicating or recording element with one  of a higher capacity, except when the 
modification has been approved by competent engineering authority, preferably that of the engineering department of the manufacturer of the automatic weighing system, and by the weights and measures authority having j urisdiction over the automatic weighing system.  
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 2.25.  Weigh -In Motion Systems –  Tentative Code   Handbook 44 –  2016  
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 Section 2.25.  Weigh -In-Motion Systems  
Used for Vehicle Enforcement Screening –  Tentative Code  
This tentative code has a trial or experimental status and is not intended to be enforced.  The requirements are 
designed for study prior to the development and adoption of a final code.  Officials wanting to conduct an official 
examination of a device or system are advised to see paragraph G -A.3. Speci al and Unclassified Equipment.  
(Tentative Code Added 2015)  
A. Application  
A.1. General . – This code applies to systems used to weigh vehicles, while in motion, for the purpose of screening 
and sorting the vehicles based on the vehicle weight to determine i f a static weighment is necessary.  
A.2. Exception.  – This code does not apply to weighing systems intended for the collection of statistical traffic 
data.  
A.3. Additional Code Requirements.  – In addition to the requirements of this code, weigh- in-motion sc reening 
systems shall meet the requirements of Section 1.10. General Code.  
S. Specifications  
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Ready Indication.  – The system shall provide a means of verifying that the system is operational and 
ready for use.  
 
S.1.2.  Value of System Division Units. –  The value of a system division “d” expressed in a unit of weight 
shall be equal to:  
 
(b) 1, 2, or 5;  or  
  
(c) a decimal multiple or submultiple of 1, 2, or 5.  
 
Examples:  divisions may be 10, 20, 50, 100; or 0.01, 0.02, 0.05; or 0.1, 0.2, 0.5, etc.  
 
S.1.2.1.  Units of Measure.  – The system shall indicate weight values using only a single unit of 
measure.   
 
S.1.3.  Maximum Value of Division.  – The value of the system division “d” for a Class A, weight -in-motion 
system shall not be greater than 50  kg (100  lb). 
 
S.1.4.  Value of Other Units of Measure.  
 
S.1.4.1.  Speed.  – Vehicle speeds shall be measured in miles per hour or kil ometers per hour.  
 
S.1.4.2.  Axle -Spacing (Length).  – The center -to-center distance between any two successive axles shall 
be measured in:  
 
(a) meters and decimal submultiples of a meter;  Handbook 44 –  2016   2.25.  Weigh -In Motion Systems –  Tentative Code  
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 (b) feet and inches; or  
(c) feet and decimal submultiples of a foot.  
S.1.4.3.  Vehicle Length.  – If the system is capable of measuring the overall length of the vehicle, the 
length of the vehicle shall be measured in feet and/or inches, or meters.  
 
S.1.5.  Capacity Indication.  – An indicating or recording element shall not display nor record any values 
greater than 105  % of the specified capacity of the load receiving element.  
 
S.1.6.  Identification of a Fault.  – Fault conditions shall be presented to the operator in a clear and 
unambiguous means.  The following fault conditions shall be identified: 
 
(a) Vehicle speed is below the minimum or above the maximum speed as specified.  
(b) The maximum number of vehicle axles as specified has been exceeded.  
(d) A change in vehicle speed greater than that specified has been detected.  
S.1.7.  Recorded Representations.  
 
S.1.7.1.  Values to be Recorded.  – At a minimum, the following values shall be printed and/or stored 
electronically for each vehicle weighment:  
 
(a) transaction identification number; 
(b) lane identification (required if more than one lane at the site has the ability to weigh a vehicle in 
motion);  
(c) vehicle speed;  
(d) number of axles;  
(e) weight of each axle;  
(f) identification and weight of axle groups;  
(g) axle spacing;  
(h) total vehicle weight;  
(i) all fault conditions that occurred during the weighing of the vehicle ; 
(j) violations, as identified in paragraph S.2.1. Violation Parameters, which occurred during the 
weighing of the vehicle; and  
(k) time and date.  
S.1.8.  Value of the Indicated and Recorded System Division.  – The value of the system’s division “(d),” as 
recorded,  shall be the same as the division value indicated.  
 
S.2. System Design Requirements.  
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 S.2.1.  Violation Parameters.  – The instrument shall be capable of accepting user -entered violation 
parameters for the following items:  
 
(a) single axle weight limit;  
(b) axle group weight limit;  
(c) gross vehicle weight limit; and  
(d) bridge formula maximum.  
The instrument shall display and/or record violation conditions when these parameters have been exceeded.  
 
S.3. Design of Weighing Elements.  
 
S.3.1.  Multiple Load -Receiving Elements.  –An instrument with a single indicating or recording element, or 
a combination indicating -recording element, that is coupled to two or more load- receiving elements with 
independent weighing systems, shall be provided with means to prohibit the ac tivation of any load -receiving 
element (or elements) not in use, and shall be provided with automatic means to indicate clearly and definitely 
which load receiving element (or elements) is in use.  
 
S.4. Design of Weighing Devices, Accuracy Class.  
 
S.4.1.  Designation of Accuracy.  – Weigh -in-motion systems meeting the requirements of this code shall be 
designated as accuracy Class A.  
 
Note:   This does not preclude higher accuracy classes from being proposed and added to this Code in the future when it 
can be demonstrated that weigh- in-motion systems grouped within those accuracy classes can achieve the higher level of 
accuracy specified for those devices.  
 
S.5. Marking Requirements . – In addition to the marking requirements in G -S.1. Identification (except 
G.S.1.(e)), the system shall be marked with the following information:  
 
(a) accuracy class;  
(b) value of the system division “d”;  
(c) operational temperature limits; 
(d) number of instrumented lanes (not required if only one lane is instrumented);  
(e) minimum and maximum vehicle speed;  
(f) maximum number of axles per vehicle;  
(g) maximum change in vehicle speed during weighment; and  
(h) minimum and maximum load.  Handbook 44 –  2016   2.25.  Weigh -In Motion Systems –  Tentative Code  
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 S.5.1.  Location of Marking Information.  – The marking information required in Section 1.10. General 
Code, G -S.1. Identification and Section 2.25. Weigh -in-Motion Systems, S.5. Marking Requirements shall be 
visible after installation.   The information shall be marked on the system or recalled from an information screen.  
N. Notes  
N.1. Test Procedures.  
 
N.1.1.  Selection of Test Vehicles.  – All dynamic testing associated with the procedures described in each of 
the subparagraphs of N.1.5 shall be performed with a minimum of two test vehicles.  
 
(a) The first test vehicle may be a two -axle, six -tire, single -unit truck; that is, a vehicle with two axles 
with the rear axle having dual wheels.  The vehicle shall have a maximum gross vehicle weight of 
10 000 lb. 
 
(b) The second test vehicle shall be a five -axle, single -trailer truck with a maximum gross vehicle weight 
of 80 000 lb. 
 
Note :  Consideration should be made for testing the systems using vehicles which are typical to the system’s daily 
operation.  
 
N.1.1.1.  Weighing of Test Vehicles.  – All test vehicles shall be weighed on a reference scale before 
being used to conduct the dynamic tests.  
 
N.1.1.2.  Determining Reference Weights for Axle, Axle Groups, and Gross Vehicle Weight.  – The 
reference weights shall be the average weight value of a minimum of three static weighments of all single 
axles, axle groups, and gross vehicle weight.  
 
Note:   The axles within an axle group are not considered single axles.  
 
N.1.2.  Test Loads.  
 
N.1.2.1.  Static Test Loads.  – All static test loads shall use certified test weights.  
 
N.1.2.2.  Dynamic Test Loads.  – Test vehicles used for dynamic testing shall be loade d to 85 to 95% of 
their legal maximum Gross Vehicle Weight. The “load” shall be non -shifting and shall be positioned to 
present as close as possible, an equal side -to-side load.  
 
N.1.3.  Reference Scale.  – Each reference vehicle shall be weighed statically on a multiple platform vehicle 
scale comprised of three individual weighing/load -receiving elements, each an independent scale.  The three 
individual weighing/load receiving elements shall be of such dimen sion and spacing to facilitate:  
  
(a) the single -draft weighing of all reference test vehicles;  
 
(b) the simultaneous weighing of each single axle and axle group of the reference test vehicles on different 
individual elements of the scale; and  
 
(c) gross vehicle wei ght determined by summing the values of the different reference axle and reference 
axle groups of a test vehicle.  
 
The scale shall be tested immediately prior to using it to establish reference test loads and in no case more than 
24 hours prior.  To quali fy for use as a suitable reference scale, it must meet NIST Handbook 44, Class  III L 
maintenance tolerances.   
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 N.1.3.1.  Location of a Reference Scale.  – The location of the reference scale must be considered since 
vehicle weights will change due to fuel c onsumption.  
 
N.1.4.  Test Speeds.  – All dynamic tests shall be conducted within 20  % below or at the posted speed limit.  
 
N.1.5.  Test Procedures .  
 
N.1.5.1.  Dynamic Load Test.  – The dynamic test shall be conducted using the test vehicles defined in 
N.1.1. Selection of Test  Vehicles .  The test shall consist of a minimum of 20 runs for each test vehicle at 
the speed as stated in N.1.4. Test Speeds.  
 
At the conclusion of the dynamic test there will be a minimum of 20  weight readings for each single axle, 
axle group, and gross vehicle weight of the test vehicle.  The tolerance for each weight reading shall be 
based on the percentage values specified in Table T.2.2. Tolerances for Accuracy Class A.  
 
N.1.5.2.  Vehicle Position Test.  – During the conduct of the dynamic testing, ensure the vehicle stays 
within the defined roadway along the width of the sensor.  The test shall be conducted with 10  runs with the 
vehicle centered along the width of the sensor; 5  runs with the vehicle on the right side along the width of  
the sensor; and 5 runs with the vehicle on the left side along the width of the sensor.  Only gross vehicle 
weight is used for this test and the tolerance for each weighment shall be based on the tolerance value 
specified in T.2.3. Tolerance Value for Veh icle Position Test.  
 
N.1.5.3.  Axle Spacing Test.  – The axle spacing test is a review of the displayed and/or recorded axle 
spacing distance of the test vehicles.  The tolerance value for each distance shall be based on the tolerance 
value specified in T.2. 4. Tolerance Value for Axle Spacing.   
T. Tolerances  
T.1. Principles.  
 
T.1.1.  Design.  – The tolerance for a weigh -in-motion system is a performance requirement independent of 
the design principle used.   
 
T.2. Tolerance Values for Accuracy Class A.  
 
T.2.1. Tests Involving Digital Indications or Representations  – To the tolerances that would otherwise be 
applied in paragraphs T.2.2. Tolerance Value for Dynamic Load Test and T.2.3. Tolerance Value for Vehicle 
Position Test, there shall be added an amount equa l to one -half the value of the scale division to account for the 
uncertainty of digital rounding.  
 
T.2.2.  Tolerance Values for Dynamic Load Test . – The tolerance values applicable during dynamic load 
testing are as specified in Table T.2.2.  
 
Table T.2.2.  
Tolerances for Accuracy Class A  
Load Description*  Tolerance as a Percentage of Applied Test Load  
Axle Load  ± 20 % 
Axle Group Load  ± 15 % 
Gross Vehicle Weight  ± 10 % 
* No more than 5  % of the weighments in each of the load description subgroups shown in this table shall 
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T.2.3.  Tolerance Value for Vehicle Position Test . – The tolerance value applied to each gross vehicle 
weighment is ±  10 % of the applied test load.  
 
T.2.4.  Tolerance Value for Axle Spacing . – The tolerance value applied to each axle spacing measurement 
shall be ±  0.15 m (0.5  ft). 
 
T.3. Influence Factors.  – The following factor is applicable to tests conducted under controlled conditions only.  
 
T.3.1.  Temperature . – Systems shall satisfy the tolerance requirements under all operating temperature 
unless a limited operating temperature range is specified by the manufacturer.  
 
T.4. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility.  – The 
difference between the weight indication due to the disturbance and the weight indication without the disturbance 
shall not exceed the tolerance value as stated in Table T.2.2. Tolerances for Accuracy Class A.  
UR. User Requirements  
UR.1.  Selection R equirements . – Equipment shall be suitable for the service in which it is used with respect to 
elements of its design, including but not limited to, its capacity, number of scale divisions, value of the scale 
division, or verification scale division and minimum capacity.   
 
UR.1.1.  General.  – The typical class or type of device for particular weighing applications is shown in 
Table  1. Typical Class or Type of Device for Weighing Applications.  
 
Table 1.  
Typical Class or Type of Device for Weighing Applications  
Class  Weighing Application  
A Screening and sorting of vehicles based on axle, axle group, and gross vehicle weight.  
Note:  A WIM system with a higher accuracy class than that specified as “typical” may be used.  
 
UR.2.  User Location Conditions and Maintenance.  – The system shall be installed and maintained as defined in 
the manufacturer’s recommendation.  
 
UR.2.1.  System Modification.  – The dimensions (e.g., length, width, thickness, etc.) of the load receiving 
element of a system shall not be chang ed beyond the manufacturer’s specifications, nor shall the capacity of a 
scale be increased beyond its design capacity by replacing or modifying the original primary indicating or 
recording element with one of a higher capacity, except when the modificatio n has been approved by a 
competent engineering authority, preferably that of the engineering department of the manufacturer of the 
system, and by the weights and measures authority having jurisdiction over the system.  
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 UR.2.2.  Foundation, Supports, and Cle arance.  – The foundation and supports shall be such as to provide 
strength, rigidity, and permanence of all components.  
  
On load -receiving elements, which use moving parts for determining the load value, clearance shall be provided 
around all live parts to the extent that no contacts may result when the load -receiving element is empty, nor 
throughout the weighing range of the system.   
 
UR.2.3.  Access to Weighing Elements. –  If necessary, adequate provision shall be made for inspection and 
maintenance of the weighing elements.  
 
UR.3.  Maximum Load.  – A system shall not be used to weigh a load of more than the marked maximum load of 
the system.  
Appendix D.   Definitions  
The specific code to which the definition applies is shown in the [brackets] at the end of  the definition.  Definitions 
for the General Code [1.10] apply to all codes in NIST Handbook 44.  
 
A 
axle.  – The axis oriented transversely to the nominal direction of vehicle motion, and extending the full width of the 
vehicle, about which the wheel(s) at both ends rotate. [2.25]  
 
axle-group load.  – The sum of all tire loads of the wheels on a group of adjacent axles; a portion of the gross -
vehicle weight. [2.25]  
 
axle load.  – The sum of all tire loads of the wheels on an axle; a portion of the gross -vehicle weight. [2.25]  
 
axle spacing . – The distance between the centers of any two axles.  When specifying axle spacing, the axels used 
also need to be identified. [2.25]  
S 
single -axle load . – The load transmitted to the road surface by the tires lying on the same longitudinal axis (that axi s 
transverse to the movement of the vehicle and about which the wheels rotate). [2.25]  
T 
tandem -axle load.  – The load transmitted to the road surface by the tires of two single -axles lying on the same 
longitudinal axis (that axis transverse to the movement  of the vehicle and about which the wheels rotate). [2.25]  
 
triple -axle load.  – The load transmitted to the road surface by the tires of three single- axles lying on the same 
longitudinal axis (that axis transverse to the movement of the vehicle and about w hich the wheels rotate). [2.25]  
 
W 
weigh -in-motion (WIM).  – A process of estimating a moving vehicle’s gross weight and the portion of that weight 
that is carried by each wheel, axle, or axle group, or combination thereof, by measurement and analysis of dy namic 
vehicle tire forces. [2.25]  
weigh -in-motion screening scale. – A weigh -in-motion  system used to identify potentially overweight vehicles . 
[2.25]  
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 wheel weight.  – The weight value of any single or set of wheels on one side of a vehicle on a single axle. [2.25]  
 
WIM System.  – A set of sensors and supporting instruments that measure the presence of a moving vehicle and the 
related dynamic tire forces at specified l ocations with respect to time; estimate tire loads; calculate speed, axle 
spacing, vehicle class according to axle arrangement, and other parameters concerning the vehicle; and process, 
display, store, and transmit this information.  This standard applies only to highway vehicles. [2.25]  
 
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 Section 3.30.  Liquid -Measuring Devices  
 
 
A. Application  
 
A.1. General.  – This code applies to:  
 
(a) devices  used for the measurement of liquids, including liquid fuels and lubricants; and  
 
(b) wholesale  devices  used for the measurement and delivery of agri -chemical  liquids such as fertilizers, feeds, 
herbicides, pesticides, insecticides, fungicides, and defoliants.  
(Added 1985)  
 
A.2. Exceptions.  – This code does not apply to:  
 
(a) meters  mounted on vehicle tanks (Also see Section  3.31. Code for Vehicle- Tank Meters.);  
 
(b) devices  used for dispensing liquefied petroleum gases (Also see Section  3.32. Code for Liquefied 
Petroleum Gas and Anhydrous Ammonia Liquid- Measuring Devices.);  
 
(c) devices  used for dispensing other liquids that do not remain in a liquid state at atmospheric pressures and 
temperatures;  
 (d) water  meters;  
 
(e) devices  used solely for dispensing a product in connection with operations in which the amount dispensed 
does not affect customer charges; or  
 
(f) mass  flow meters.  (Also see Section  3.37. Code for Mass Flow Meters.)  
(Added 1994)  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, liquid -measuring devices 
shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Indicating and Recording Elements and Recorded Representations.  
 
S.1.1.  General.  – A liquid -measuring device:  
 
(a) shall  be equipped with a primary indicating element ; and  
 
(b) may be equipped with a primary recording element.  
 
S.1.2.  Units.  – A liquid -measuring device shall indicate, and record if the device is equipped to record, 
its deliveries in liters, gallons, quarts, pints, fluid ounces, or binary -submultiples  or decimal subdivisions of the 
liter or gallon.  
(Amended 1987, 1994, and 2006)  
 
S.1.2.1.  Retail Motor -Fuel Devices.  – Deliveries shall be indicated and recorded, if the device is 
equipped to record, in liters or gallons and decimal subdivisions or fractional equivalents there of. 
(Added 1979)  
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 S.1.2.2.  Agri -Chemical  Liquid Devices.  
 
S.1.2.2.1.  Liquid Measure.  – Deliveries shall be indicated and recorded in liters or gallons and 
decimal subdivisions or fractional equivalents thereof.  
 
S.1.2.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated delivery, and recorded 
delivery if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) 0.5 L (0.1  gal) on devices with a maximum rated flow rate of 750  L/min (200 gal/min) or less;  
 
(b) 5 L (1 gal) on devices with a maximum rated flow of more than 750  L/min (200 gal/min); or  
 (c) 5 L (1 gal) on meters with a rated maximum flow rate of 375 L/min (100 gal/min) or more used 
for jet fuel aviation refueling systems.  
(Added 2007)  
 This requirement does not apply to manually operated devices equipped with stops or stroke -limiting 
means.  
(Amended 1983, 1986, and 2007)  
 
S.1.3.  Advancement of Indicating and Recording Elements.  – It shall not be possible to advance 
primary indicating and recording elements  except by the mechanical operation of the device.  Clearing a device 
by advancing its elements to zero is permitted, but only if:  
 
(a) once  started, the advancement  movemen t cannot be stopped until zero is reached; and  
 (b) in the case of indicating elements  only, such elements are automatically obscured until the elements 
reach the correct zero position.  
 
S.1.4.  Graduations.  
 
S.1.4.1.  Length.  – Graduations  shall be varied in length so that they may be conveniently read.  
 
S.1.4.2.  Width.  – In a series of graduations , the width of:  
 
(a) every  graduation shall be at least 0.2  mm (0.008 in) but not greater than the minimum clear 
interval  between graduations ; and  
 (b) main  graduations  shall be not more than 50  % greater than the width of subordinate graduations . 
 
S.1.4.3.  Clear Interval Between Graduations.  – The clear interval  between graduations  shall be not 
less than 1.0  mm (0.04  in).  If the graduations are not parallel, the measurement shall be mad e: 
 
(a) along the line of movement of the tip of the index of the indicator as it passes over the 
graduations ; or 
 (b) if the indicator extends over the entire length of the graduations,  at the point of widest separation 
of the graduations.  
 
S.1.5.  Indicators.  
 
S.1.5.1.  Symmetry.  – The portion of the index of an indicator  associated with the graduations  shall be 
symmetrical with respect to the graduations.  
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 S.1.5.2.  Length.  
 
(a) If the indicator and the graduations  are in different planes, the index of the indicator shall extend 
to each graduation with which it is to be used.  
 
(b) If the indicator is in the same plane as the graduations , the distance between the index of the 
indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.5.3.  Width.  
 
(a) The index of an indicator  shall not be wider than the width of the narrowest graduation.  
[Nonretroactive  as of January  1, 2002]  
(Amended 2000)  
 
(b) If the index of an indicator  extends over the entire length of a graduation, it shall be of uniform 
width throughout the portion that coincides with the graduation.  
 
S.1.5.4.  Clearance.  – If the indicator and the graduations  are in different planes, the clearance between 
the index of an indicator  and the plane of the graduations shall be no greater than 1.5  mm (0.06  in). 
 S.1.5.5.  Parallax.  – Parallax effects shall be reduced to the practical minimum.  
 
S.1.6.  Additional Operating Requirements, Retail Devices (Except Slow -flow Meters).  
 
S.1.6.1.  Indication of Delivery.  – The device shall automatically show on its face the initial zero 
condition and the quantity  delivered (up to the nominal capacity).  However, the following requirements 
shall apply:  
 For electronic devices manufactured prior to January  1, 2006, the first 0.03 L (or 0.009 gal) of a delivery 
and its associated total sales price need not be indicated.  
 
For electronic devices manufactured on or after January  1, 2006, the measurement, indication of delivered  
quantity, and the indication of total sales price  shall be inhibited until the fueling position reaches 
conditions necessary to ensure that the delivery starts at zero.  
[Nonretroactive  as of January  1, 2006]  
(Added 2005)  
(Amended 1982 and 2005)  
 
S.1.6.2.  Provisions for Power Loss.  
 
S.1.6.2.1.  Transaction Information.  – In the event of a power loss,  the information needed to 
complete any transaction in progress at the time of the power loss (such as the quantity  and unit price , 
or sales price) shall be determinable for at least 15 minutes at the dispenser or at the console if the 
console is accessible to the customer.  
[Nonretroactive  as of January  1, 1983]  
 
S.1.6.2.2.  User Information.  – The device memory shall retain information on the quantity  of fuel 
dispensed and the sales price totals during power loss.  
[Nonretroactive  as of January  1, 1983]  
 
S.1.6.3.  Return to Zero.  
 
(a) The primary indicating elements , and primary recording elements  if the device is equipped to 
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 other self -operated device may be equipped with cumulative indicating or recording elements, 
provided that it is also equipped with a zero -return indicating element.  
 
(b) It shall not be possible to return primary indicating elements , or primary recording elements  
beyond the correct zero position.  
(Amended 1972)  
 
S.1.6.4.  Display of Unit Price  and Product Identity.  
 
S.1.6.4.1.  Unit Price.  
 
(a) A computing or money -operated device shall be able to display on each face the unit price  at 
which the device is set to compute or to dispense.  
 
(b) Except for dispensers used exclusively for fleet sales, other price contract  sales, and truck 
refueling (e.g., truck stop dispensers used only to refuel trucks), whenever a grade , brand, 
blend, or mixture is offered for sale from a device at more than one unit price , then all of the 
unit prices at which that product is offered for sale shall meet the following conditions:  
 
(1) For a system that applies a discount prior to the delivery, all unit prices shall be displayed or shall be capable of being displayed on the dispenser through a deliberate 
action of the customer prior to the delivery of the product.  It is not necessary that all of 
the unit prices for all grades, brands, blends,  or mixtures be simultaneously displayed 
prior to the delivery of the product.   
[Effective and Nonr etroactive  as of January  1, 1991]  
 
(2) For a system that offers post -delivery discounts on fuel sales, display of pre -delivery unit 
price information is exempt from (b)(1), provided the system complies with 
S.1.6.8.  Recorded Representations for Transactio ns Where a Post -Delivery Discount(s) 
is Provided.  
(Added 2012)  
 
Note : When a product is offered at more than one unit price, display of the unit price information may be 
through the deliberate action of the customer: 1) using controls on the device; 2) through the customer’s 
use of personal or vehicle- mounted electronic equipment communicating with the system; or 3) verbal 
instructions by the customer.  
(Added 2012)  
 (Amended 1989, 1997, and 2012)  
 
S.1.6.4.2.  Product Identity.  
 
(a) A device shall be able to conspicuously display on each side the identit y of the product being 
dispensed.  
 
(b) A device designed to dispense more than one grade,  brand, blend,  or mixture of product also 
shall be able to display on each side the identity of the grade, brand, blend, or mixture being 
dispe nsed.  
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 S.1.6.5.  Money -Value  Computations.  
 
(a) A computing device  shall compute the total sales price at any single -purchase unit price  
(i.e., excluding fleet sales,  other price contract sales,  and truck stop dispensers used only to refuel 
trucks) for which the product being measured is offered for sale at any delivery possible within 
either the measurement range of the device or the range of the computing elements, whichever is 
less. 
[Effective and Nonretroactive  as of January  1, 1991]  
 
(b) The analog sales price indicated for any delivered quantity  shall not differ from a mathematically 
computed price (quantity × unit price  = total sales price) by an amount greater than the value in 
Table  1. Money -Value Divisions and Maximum Allowable Variations for Money -Value 
Computations on Mechanical Analog Computers.  
(Amended 1984, 1989, and 1993)  
 
S.1.6.5.1.  Money -Value  Divisions,  Analog.  – The values of the graduated intervals representing 
money values on a computing type device shall be no greater than those in Table  1. Money -Value 
Divisions and Maximum Allowable Variations for Money -Value C omputations on Mechanical Analog 
Computers.  
(Amended 1991)  
 
Table 1.  
Money -Value Divisions  and 
Maximum Allowable Variations for Money- Value  
Computations on Mechanical Analog Computers  
Unit Price  
Money -Value  
Division  Maximum  
Allowable Variation  
From  To and including  Design  
Test Field  
Test 
                0  $0.25/liter or 
$1.00/gallon  1¢ ± 1¢ ± 1¢ 
$0.25/liter or  
$1.00/gallon  $0.75/liter or  
$3.00/gallon  1¢ or 2¢  ± 1¢ ± 2¢ 
$0.75/liter or  
$3.00/gallon  $2.50/liter or  
$10.00/gallon 1¢ or 2¢  ± 1¢ ± 2¢ 
    $0.75/liter or  
$3.00/gallon  $2.50/liter or  
$10.00/gallon 5¢ ± 2½¢  ± 5¢ 
 
S.1.6.5.2.  Money -Value Divisions,  Digital.  – A computing type device with digital indications 
shall comply with the requirements of paragraph  G.S.5.5. Money -Values, Mathematical Agreement , 
and the total price computation shall be based on quantities not exceeding 0.05 L for devices indicating 
in metric units and 0.01  gal intervals for devices indicating in U.S. customary units.  
(Added 1980)  
 
S.1.6.5.3.  Auxiliary Elements.  – If a system is equipped with auxiliary indications, all indicated 
money -value divisions  of the auxiliary element shall be identical with those of the primary element.  
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S.1.6.5.4.  Selection of Unit Price.  – A system shall not permit a change to the unit price during 
delivery of product.  When a product or grade  is offered for sale at more than one unit price through a 
computing device , the following conditio ns shall be met:   
 
Except for a system only capable of applying a post -delivery discount(s), the selection of the unit 
price shall be made prior to delivery through a deliberate action of the customer to select the 
unit price for the fuel delivery.  
 [Nonretroactive  as of January  1, 1991]  
 
For a system only capable of applying a post -delivery discount(s), the selection of the unit price 
shall be made through a deliberate action of the customer to select the unit price for the fuel 
delivery.   
 (Added 2012)  
 
Note:  When a product is offered at more than one unit price, selection of the unit price may be through the 
deliberate action of the customer:  1) using controls on the device; 2) through the customer’s use of personal or 
vehicle -mounted electronic equipment communicating with the system; or 3) verbal instructions by the customer .  
 (Added 2012)  
 
 The provisions in (a) and (b) do not apply to dispensers used exclusively for fleet sales , other price 
contract sales , and truck refueling (e.g., truck stop dispensers used only to refuel trucks).  
(Added 1989) (Amended 1991, 1992, 1993, 1996, and 2012)  
 
S.1.6.5.5.  Display of Quantity and Total Price. –  Except for aviation refueling applicati ons, when 
a delivery is completed, the total price and quantity for that transaction shall be displayed on the face of the dispenser for at least five  minutes or until the next transaction is initiated by using controls  on 
the device or other customer -activated controls.  
[Nonretroactive  as of January  1, 1994]  
(Added 1992) (Amended 1996 and 2007)  
 
S.1.6.5.6.  Display of Quantity and Total Price, Aviation Refueling Applications.  
 
(a) The quantity shall be displayed throughout the transaction.  
 
(b) The total price shall also be displayed under one of the following conditions:  
 
(1) The total price can appear on the face of the dispenser or through a controller adjacent to 
the device.  
 
(2) If a device is designed to con tinuously compute and display the total price, then the total 
price shall be computed and displayed throughout the transaction for the quantity 
delivered.  
 
(c) The total price and quantity shall be displayed for at least five  minutes or until the next 
transaction is initiated by using controls  on the device or other customer -activated controls.  
 (d) A printed receipt shall be available and shall include, at a minimum, the total price, quantity, 
and unit price.  
[Nonretroactive  as of January  1, 2008]  
(Added 2007)  
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 S.1.6.6.  Agreement  Between Indications.   
 
(a) When a quantity  value indicated or recorded by an auxiliary element is a derived or computed 
value based on data received from a retail motor fuel dispenser, the value may differ from the 
quantity value displayed on the dispenser, provided the following conditions are me t: 
 
(1) all total money -values for an individual sale that are indicated or recorded by the system 
agree; and  
 
(2) within  each element, the values indicated or recorded meet the formula (quantity  × unit  
price  = total sales price) to  the closest cent.  
[Nonretroactive  as of January  1, 1988]  
 
(b) When a system applies a post -delivery discount(s) to  a fuel’s  unit price through an auxiliary 
element, the following conditions shall apply for computed  values:  
 
(1) the total volume of the delive ry shall be in agreement between all elements in the system.  
(Added 2012)  
(Added 1985) (Amended 1987, 1988, and 2012)  
 
S.1.6.7.  Recorded Representations. –  Except for fleet sales  and other price contract sales  and for 
transactions where a post -delivery discount is provided , a printed receipt providing the following 
information shall be available through a built -in or separate recording element  for all transactions 
conducted with point -of-sale systems or devices activated by debit cards, credit cards, and/or cash:  
 
(a) the total volume of the delivery;  
 (b) the unit price ; 
 
(c) the total computed price; and  
 
(d) the product identity  by name, symbol, abbreviation, or code number.  
[Nonretroactive  as of January  1, 1986]  
(Added 1985) (Amended 1997, 2012, and 2014)  
 
S.1.6.8.  Recorded Representations for Transactions Where a Post -Delivery Discount(s) is 
Provide d. – Except for f leet sales and other price contract sales, a printed receipt providing the following 
information shall be available through a built -in or separate recording element that is part of the system for 
transactions involving a post -delivery discount:  
 
(a) the product identity  by name, symbol, abbreviation, or code number;  
 
(b) transaction  information as shown on the dispenser at the end of the delivery and prior to any post -
delivery discount(s), including the:  
 
(1) total volume of the delivery;  
 (2) unit price; and  
 
(3) total computed price of the fuel sale.  
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 (c) an itemization of the post -delivery discounts to the unit price; and  
 
(d) the final total price of the fuel sale after all post -delivery discounts are applied.  
 (Added 2012) (Amended 2014)  
 
S.1.6.9. Lubricant  Devices , Travel of Indicator.  – The indicator shall move at least 2.5  cm (1  in) in 
relation to the graduations , if provided, for a delivery of 0.5 L (1 pt). 
 
S.1.7.  Additional Operating Requirements,  Wholesale Devices Only.  
 
S.1.7.1.  Travel of Indicator.  – A wholesale device shall be readily operable to deliver accurately any 
quantity from 200 L (50  gal) to the  capacity of the device.  If the most sensitive element of the indicating 
system utilizes an indicator and graduations , the relative movement of these parts corresponding to a 
delivery of 4  L (1 gal) shall be not less than 5  mm (0.20  in). 
(Amended 1987)  
 
S.1.7.2.  Money -Values – Mathematical Agreement.  – Any digital money- value indication and any 
recorded money -value on a computing -type device shall be in mathematical agreement  with its associated 
quantity indication or representation to within 1  cent of money -value.  
 
S.2. Measuring Elements.  
 
S.2.1.  Vapor Elimination.  
 
(a) A liquid -measuring device shall  be equipped with a vapor or air eliminator or other automatic  means to 
prevent the passage of vapor and air through the meter.  
 
(b) Vent lines from the air or vapor eliminator shall be made of metal tubing or other rigid material.  
(Amended  1975)  
 
S.2.1.1.  Vapor Elimination on Loading Rack Metering Systems.  
 
(a) A loading rack metering system shall be equipped with a vapor or air eliminator or other automatic means to prevent the passage of vapor and a ir through the meter unless the system is designed or 
operationally controlled by a method, approved by the weights and measures jurisdiction having control over the device, such that air and/or vapor cannot enter the system.  
 
(b) Vent lines from the air o r vapor eliminator (if present) shall be made of metal tubing or other rigid 
material.  
(Added 1994)  
 
S.2.2.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security  
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before an adjustment or interchange can be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element  for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries; and  
 
(c) any metrological parameter that will affect the metrological integrity of the device or system.  
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 When applicable, the adjusting mechanism  shall be readily accessible for purposes of affixing a security  
seal. 
[Audit trails shall use the format set forth in Table  S.2.2. ]* 
[*Nonretroactive and Enforceable as of January  1, 1995]  
(Amended 1991, 1993, 1995, and 2006)  
 
 
Table S.2.2.  
Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal  or two event counters:  one for 
calibration parameters and one for configuration 
parameters.  
Category  2:  Remote configuration capability, but access 
is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable of printing in this mode or shall not operate while in this 
mode.  [The hardware enabling access for remote 
communication must be on- site.  The hardware must be 
sealed using a physical seal  or an event counter for 
calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or at 
the system controller; however, an adequate number of 
counters must be provided to monitor the calibration and 
configuration parameters of the individual devices at a 
location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of the 
informatio n through an on -site device.]*  
[*Nonretroactive as of January  1, 1996]  
Category  3:  Remote configuration capability access may 
be unlimited or controlled through a software switch 
(e.g., password) . 
[Nonretroactive as of January  1, 1995]  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  
[Nonretroactive  as of January  1, 2001]  An event logger is required in the device; it must incl ude 
an event counter (000 to 999), the parameter ID, the date 
and time of the change, and the new value of the 
parameter.  A printed copy of the information must be 
available on demand through the device or through 
another on- site device.   The information may also be 
available electronically.   The event logger shall have a 
capacity to retain records equal to 10 times the number 
of sealable parameters in the device, but not more than 
1000 records are required.  ( Note :  Does not require 
1000 changes to be sto red for each parameter.)  
[Nonretroactive as of January  1, 1995]  
(Table Added 1993) (Amended 1995, 1998, 1999, 2006, and 2006 2015)  
 
S.2.3.  Directional Flow Valves.  – Valves  intended to prevent reversal of flow shall be automatic  in 
operation.  
 
S.2.4.  Stop Mechanism.  
 
S.2.4.1.  Indication.  – The delivery for which the device is set shall be conspicuously indicated.  
(Amended 1983)  
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 S.2.4.2.  Stroke Limiting Elements.  – Stops or other stroke limiting elements subject to direct pressure 
or impact shall be:  
 
(a) made secure by positive, nonfrictional engagement of these elements; and  
 (b) adjustable  to provide for deliveries within tolerances.  
(Amended 1983)  
 
S.2.4.3.  Setting.  – If two or more stops or other elements may be selectively brought into operation to 
permit predetermined quantities of deliveries:  
 
(a) the position for the proper setting of each such element shall be accurately defined; and  
 (b) any inadvertent displacement from the proper setting shall be obstructed.  
(Amended 1983)  
 
S.2.5.  Zero -Set-Back Interlock, Retail Motor -Fuel Devices.  – A device shall be constructed so that:  
 
(a) after a delivery cycle has been completed by moving the starting lever to any position that shuts off the 
device, an automatic  interlock  prevents a subsequent delivery until the  indicating elements , and 
recording elements  if the device is equipped and activated to record, have been returned to their zero 
positions;  
 
(b) the discharge nozzle cannot be returned to its designed hangin g position (that is, any position where 
the tip of the nozzle is placed in its designed receptacle and the lock can be inserted) until the starting 
lever is in its designed shut -off position and the zero- set-back interlock  has been engaged; and  
 
(c) in a system with more than one dispenser supplied by a single pump, an effective automatic  control 
valve in each dispenser prevents product from being delivered until the indicating elements  on that 
dispenser are in a correct zero position.  
(Amended 1981 and 1985)  
 
S.2.6.  Temperature Determination –  Wholesale Devices.  – For test purposes, means shall be provided 
(e.g., thermometer well)  to determine the temperature of the liquid either:  
 
(a) in the liquid chamber of the meter; or  
 
(b) in the meter inlet or discharge line immediately adjacent to the meter.  
[Nonretroactive as of January  1, 1985]  
(Added 1984) (Amended 1986)  
 
S.2.7.  Wholesale Devices Equipped with Automatic Temperature Compensators.   
 
S.2.7.1.  Automatic Temperature Compensation.  – A device may be equipped with an automatic  
means for adjusting the indication and registration of the measured volume of product to the volume at 
15 °C (60  °F). 
 S.2.7.2.  Provision for Deactivating.  – On a device equipped with an automatic  temperature -
compensating mechanism that will indicate or record only in terms of gallons compensated to 15  °C 
(60 °F), provision shall be made for deactivating the automatic temperature -compensating mechanism so 
that the m eter can indicate and record, if it is equipped to record, in terms of the uncompensated volume.  
(Amended 1972)  
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 S.2.7.3.  Provision for Sealing Automatic Temperature -Compensating Systems.  – Provision shall be 
made for applying security  seals in such a manner that an automatic  temperature -compensating system 
cannot be disconnected and that no adjustment may be made to the system without breaking the seal.  
 
S.2.7.4.  Temperature Determination  with Automatic  Temperature -Compensation.  – For test 
purposes, means shall be provided (e.g., thermometer well) to determine the temperature of the liquid 
either:  
 
(a) in the liquid chamber of the meter; or  
 
(b) immediately adjacent to the meter in the meter inlet or discharge line.  
(Amended 1987)  
 
S.2.8.  Exhaustion of Supply, Lubricant Devices Other than Meter Types.  – When the level of the 
supply of lubricant becomes so low as to compromise the accuracy of measurement, the device shall:  
 
(a) automatically become inoperable; or  
 
(b) give a conspicuous and distinct warning.  
 
S.3. Discharge Lines and Valves.  
 
S.3.1.  Diversion of Measured Liquid.  – No means shall be provided by which any measured liquid can 
be diverted from the measuring chamber of the meter or its discharge line.  Two or more delivery outlets may 
be installed only if au tomatic means are provided to ensure that:  
 
(a) liquid can flow from only one outlet at a time; and  
 
(b) the direction of flow for which the mechanism may be set at any time is clearly and conspicuously 
indicated.  
 
An outlet that may be opened for purging or draining the measuring system or for recirculating,  if recirculation 
is required in order to maintain the  product in a deliverable state, shall be permitted only when the system is 
measuring food products, agri -chemicals, biodiesel, or biodiesel blends.  Effective automatic means shall be 
provided to prevent passage of liquid through any such outlet during normal operation of the measuring system 
and to inhibit meter indications (or advancement of indications) an d recorded representations while the outlet is 
in operation.  
(Amended 1991, 1995, 1996, and 2007)  
 
S.3.2.  Exceptions.  – The provisions of S.3.1. Diversion of Measured Liquid shall not apply to truck 
refueling  devices when diversion of  flow to other than the receiving vehicle cannot readily be accomplished and 
is readily apparent.  Allowable deterrents include, but are not limited to, physical barriers to adjacent driveways, visible valves,  or lighting systems that indicate  which outlets are in operation, and explanatory signs.  
(Amended 1982, 1990, 1991, and 2002)  
 
S.3.3.  Pump -Discharge Unit.  – A pump -discharge unit  equipped with a flexible discharge hose  shall be 
of the wet -hose type.  
 S.3.4.  Gravity- Discharge Unit.  – On a gravity- discharge unit : 
 
(a) the discharge hose  or equivalent pipe shall be of the dry -hose type with no shutoff valve at its outlet 
end unless the hose or pipe drains to the same level under all conditions of use;  
 (b) the dry -hose shall be sufficiently stiff and only as long as necessary to facilitate drainage;  
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 (c) an automatic  vacuum breaker, or equivalent mechanism, shall be incorporated to prevent siphoning 
and to ensure rapid and complete drainage; and  
 
(d) the inlet end of the hose or outlet pipe shall be high enough to ensure complete drainage.  
 
S.3.5.  Discharge Hose, Rein forcement.  – A discharge hose  shall be reinforced so that the performance 
of the device is not affected by the expansion or contraction of the hose.  
 
S.3.6.  Discharge Valve.  – A discharge valve may be installed in the discharge line only if the device is 
of the wet -hose type.  Any other shutoff valve on the discharge side of the meter shall be of the automatic or 
semiautomatic predetermined -stop type or shall be operable only:  
 
(a) by means of a tool (but not a pin) entirely separate from the device; or  
 
(b) by mutilation of a security  seal with which the valve is sealed open.  
 
S.3.7.  Anti -drain Means.  – In a wet -hose pressure -type device, means shall be incorporated to prevent 
the drainage of the discharge hose . 
(Amended 1990)  
 
S.4. Marking Requirements.  
 
S.4.1.  Limitation on Use.  – The limitations on its use shall be clearly and permanently marked on any device 
intended to measure accurately only:  
 
(a) products having particular properties;  
 
(b) under specific installation or operating conditions; or  
 (c) when used in conjunction with specific accessory equipment.  
 
S.4.2.  Air Pressure.  – If a device is operated by air pressure, the air pressure gauge shall show by 
special graduations  or other means the maximum and minimum working pressures recommended by the 
manufacturer.  
 
S.4.3.  Wholesale Devices.  
 
S.4.3.1.  Discharge Rates.  – A wholesale device shall be marked to show its designed maximum and 
minimum discharge rates.   However, the minimum discharge rate shall not exceed 20  % of the maximum 
discharge rate.  
 
S.4.3.2.  Temperature Compensation.  – If a device is equipped with an automatic  temperature 
compensation , the primary indicating elements,  recording elements,  and recorded representation shall be 
clearly and conspicuously marked to show that the volume delivered has been adjusted to the volume at 15 °C (60  °F). 
 
S.4.4.  Retail Devices.  
 
S.4.4.1.  Discharge Rates.  – On a retail device with a designed maximum discharge rate  of 115 L 
(30 gal) per minute or greater, the maximum and minimum discharge rates shall be marked in accordance 
with S.4.4.2.  Location of Marking Information; Retail Motor -Fuel Dispensers.  The marked minimum 
discharge rate shall not exceed 20 % of the mar ked maximum discharge rate.  
[Nonretroactive as of January  1, 1985]  
(Added 1984) (Amended 2003)  
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 Example:  With a marked maximum discharge rate of 230  L/min (60  gpm), the marked minimum discharge 
rate shall be 45  L/min (12  gpm) or less (e.g., 40  L/min [10 gpm] is acceptable).  A marked minimum 
discharge rate greater than 45  L/min (12  gpm) (e.g., 60  L/min [15  gpm]) is not acceptable.  
 
S.4.4.2.  Location of Marking Information; Retail Motor -Fuel Dispensers.  – The marking information 
required in the General  Code, paragraph G-S.1. Identification  shall appear as follows:  
 
(a) within 60  cm (24  in) to 150 cm (60  in) from the base of the dispenser;  
 
(b) either internally and/or externally provided the information is permanent and easily read; and  
 
(c) on a portion of the dev ice that cannot be readily removed or interchanged (i.e., not on a service 
access panel).  
 
Note:  The use of a dispenser key or tool to access internal marking information is permitted for retail 
liquid -measuring devices.  
[Nonretroactive as of January  1, 2003]  
(Added 2002) (Amended 2004)  
 
S.5. Totalizers for Retail Motor -Fuel Dispensers.  – Retail motor -fuel dispensers shall be equipped with a non-
resettable totalizer for the quantity  delivered through the metering device.  
[Nonretroactive  as of January  1, 1995]  
(Added 1993) (Amended 1994)  
 
N. Notes  
 
N.1. Test Liquid.  
 
N.1.1.  Type of Liquid.  – The liquid used for testing a liquid -measuring device shall be the type the 
device is used to measure, or another liquid with the same general physical characteristics.  
 
N.1.2.  Labeling.  – Following the completion of a successful examination of a wholes ale device, the 
weights and measures official should attach a label or tag indicating the type of liquid used during the test.  
 
N.2. Volume Change.  – Care shall be taken to minimize changes in volume of the test liquid due to temperature 
changes and evapor ation losses.  
 
N.3. Test Drafts.  
 
N.3.1.  Retail Piston -Type and Visible -Type Devices.  – Test drafts  shall include the full capacity 
delivery and each intermediate delivery for which the device is designed.  
 
N.3.2.  Slow -flow Meters.  – Test drafts shall be equal to at least four times the minimum volume that can 
be measured and indicated through either a visible indication or an audible signal.  
 
N.3.3.  Lubricant Devices.  – Test drafts shall be 1  L (1 qt).  Additional test drafts  may include 0.5  L 
(1 pt), 4 L (4 qt), and 6 L (6 qt). 
 N.3.4.  Other Retail Devices.  – On devices with a designed maximum discharge rate of: 
 
(a) less than 80  L (20  gal) per minute, tests shall include drafts of one or more amounts, including a draft 
of at least 19  L (5 gal). 
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 (b) 80 L (20  gal) per minute or greater, tests shall include drafts of one or more amounts, including a draft 
of at least the amount delivered by the device in one minute at the maximum flow rate of the 
installation.  
(Amended 1984)  
 N.3.5.  Wholesale Devices.  – The delivered quantity  should be equal to at least the amount delivered by 
the device in one  minute at its maximum discharge rate , and shall in no case be less than 200  L (50  gal). 
(Amended 1987 and 1996)  
 
N.4. Testing Procedures.  
 
N.4.1.  Normal Tests.  – The “normal” test of a device shall be made at the maximum discharge flow rate 
developed under the conditions of installation.  Any additional tests conducted at flow rates down to and 
including one -half of the sum of the maximum discharge  flow rate and the rated minimum discharge flow rate 
shall be considered normal tests.  
(Amended 1991)  
 
N.4.1.1.  Wholesale Devices Equipped with Automatic Temperature -Compensating Systems.  – On 
wholesale devices  equipped with automatic  temperature -compensating systems , normal tests  shall be 
conducted:  
 
(a) by comparing the compensated volume indicated or recorded to the actual delivered volume 
corrected to 15  °C (60  °F); and  
 (b) with the temperature -compensating system deactivated, comparing the uncompensated volume 
indicated or recorded to the actual deliver ed volume.  
 
The first test shall be performed with the automatic  temperature -compensating system operating in the “as 
found” condition.  
 
On devices that indicate or record both the compensated and uncompensated volume for each delivery, the  
tests in (a) and (b) may be performed as a single test.  
(Amended 1987)  
 
N.4.1.2.  Repeatability Tests. –  Tests for repeatability  should include a minimum of three consecutive 
test drafts  of approximately the same size and be conducted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2001)  
 
N.4.2.  Special Tests.  – “Speci al” tests shall be made to develop the operating characteristics of a device 
and any special elements and accessories attached to or associated with the device.  Any test except as set forth 
in N.4.1. Normal Tests shall be considered a special test.  
 
N.4.2.1.  Slow -Flow Meters.  – A “special” test shall be made at a flow rate:  
 
(a) not larger than twice the actual minimum flow rate; and  
 
(b) not smaller than the actual minimum flow rate of the installation.  
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 N.4.2.2.  Retail Motor -Fuel Devices.  
 
(a) Devices without a marked minimum flow -rate shall have a “special” test performed at the slower 
of the following rates:  
 
(1) 19 L (5 gal) per minute; or  
 
(2) the minimum discharge rate  at which the device will deliver when equipped with an automatic  
discharge nozzle set at its slowest setting.  
 
(b) Devices with a marked minimum flow -rate shall have a “special” test performed at or near the 
marked minimum flow rate.  
(Adde d 1984) (Amended 2005)  
 
N.4.2.3.  Other Retail Devices.  – “Special” tests of other retail devices shall be made at the slower of the 
following rates:  
 
(a) 50 % of the maximum discharge rate  developed under the conditions of installation; or  
 (b) the minimum discharge rate  marked on the device.  
 
N.4.2.4.  Wholesale Devices.  – “Special” tests shall be made to develop the operating characteristics of a 
measuring system and any special associated or attached elements and accessories.  “Special” tests shall include a test at or slightly above the slower of the following rates: 
 
(a) 20 % of the marked maximum discharge rate; or  
 (b) the minimum discharge rate  marked on the device.  
 
In no case shall the test be performed at a flow rate less than the minimum discharge rate marked on the device.  
(Amended 2014)  
 
N.4.3.  Money -Value Computation Tests.  
 
N.4.3.1.  Laboratory Tests.  – When testing the device in the laboratory:  
 
(a) compliance with paragraph  S.1.6.5. Money -Value Computations , shall be determined by using the 
cone gear as a reference for the total quantity delivered;  
 (b) the indicated quantity  shall agree with the cone gear representation with the index of the indicator 
within the width of the graduation; and  
 (c) the maximum allowable variation of the indicated sales price shall be as shown in Table 1. 
Money- Value Divisions and Maximum Allowable Variations for Money -Value Computations on 
Mechanical Analog Computers.  
(Amended 1984)  
 
N.4.3.2.  Field  Tests.  – In the conduct of field tests to determine compliance with 
paragraph  S.1.6.5. Money -Value Computations, the maximum allowable variation in the indicated sales 
price shall be as shown in Table 1. Money -Value Divisions and Maximum Allowable Variations for 
Money- Value Computations on Mechanical Analog Computers . 
(Add ed 1982) (Amended 1984)  
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 N.4.4.  Pour and Drain Times.  
 
N.4.4.1.  Pour and Drain Times for Hand -held Test Measures. – Hand -held test measures require a 
30-second (±  5 seconds) pour followed by a 10- second drain with the measure held at a 10 -degree to 
15-degree angle from vertical.  
 
N.4.4.2.  Drain Times for Bottom Drain Test Measures or Provers. –  Bottom drain field standard 
provers require a 30 -second drain time after main flow cessation.  
(Added 2009)  
 
N.5. Temperature Correction on Wholesale Devices.  – Corrections shall be made for any changes in volume 
resulting from the differences in liquid temperatures between time of passage through the meter and time of volumetric determination in the prover.  Whe n adjustments are necessary, appropriate petroleum measurement tables 
should be used.  
(Amended 1974)  
 
T. Tolerances  
 
T.1. Application to Underregistration and to Overregistration.  – The tolerances  hereinafter prescribed shall be 
applied to errors of underregistration and errors of overregistration, whether or not a device is equipped with an 
automatic  temperature compensator.  
 T.2. Tolerance Values.  – Maintenance, acceptance, and special test tolerances shall be as shown in 
Table  T.2. Accuracy Classes and Tolerances for Liquid Measuring Devices Covered in NIST Handbook  44, 
Section  3.30.  
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 Table T.2.  
Accuracy Classes and Tolerances for Liquid Measuri ng Devices Covered in  
NIST Handbook  44, Section  3.30.  
Accuracy 
Class  Application  Acceptance 
Tolerance Maintenance  
Tolerance Special Test 
Tolerance1 
0.3 - Petroleum products delivered from large capacity 
(flow rates greater than 115  L/min or 30 gpm)** 
devices, including motor -fuel devices  
- Heated products (other than asphalt) at 
temperatures greater than 50  °C (122 °F) 
- Asphalt at temperatures equal to or below 50 °C 
(122 °F) 
- All other liquids not shown in the table where the 
typical delivery is over 200  L (50  gal) 0.2 %  0.3 %  0.5 %  
0.3A  - Asphalt at temperatures greater than 50  °C (122 °F)  0.3 %  0.3 %  0.5 %  
0.5* - Petroleum products delivered from small capacity (at 4  L/min (1  gpm) through 115 
L/min or 
30 gpm) ** motor -fuel devices  
- Agri-chemical  liquids  
- All other applications not shown in the table where 
the typical delivery is ≤  200 L (50  gal) 0.3 %  0.5 %  0.5 %  
1.1 - Petroleum products and other normal liquids from 
devices  with flow rates** less than 1  gpm.  
- Devices designed to deliver less than 1  gal 0.75 %  1.0 %  1.25 %  
* For test drafts ≤  40 L or 10 gal, the tolerances specified for Accuracy Class  0.5 in the table above do not apply.  
For these test drafts, the following applies:  
(a) Maintenance tolerances on normal and special tests shall be 20  mL plus 4  mL per indicated liter or 1  in3 
plus 1  in3 per indicated gallon.  
(b) Acceptance tolerances on n ormal and special tests shall be one -half the maintenance tolerance values.  
1 Special test tolerances are not applicable to retail motor fuel dispensers.  
** Flow rate refers to designed or marked maximum flow rate.  
(Added 2002) (Amended 2006 and 2013)  
 
T.3. Repeatability . – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance  tolerance 
and the results of each test shall be within the applicable tolerance.  This tolerance does not apply to the test of the automatic  temperature- compensating system.  (Also see N.4.1.2. Repeatability Tests.)  
(Added 1992) (Amended 2001 and 2002)  
 T.4. Automatic Temperature -Compensating Systems.  – The difference between the meter error (expressed as a 
percentage) for results determined with and without the automatic  temperature -compensating system activated shall 
not exceed:  
 
(a) 0.2 % for mechanical automatic  temperature -compensating systems ; and  
 
(b) 0.1 % for electronic automatic  temperature -compensating systems.  
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 The delivered quantities for each test shall be approximately the same size.  The results of each test shall be within 
the applicable acceptance  or maintenance  tolerance.  
[Nonretroactive as of January  1, 1988]  
(Added 1987) (Amended 1992, 1996, and 2002)  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1.  Discharge Hose.  
 
UR.1.1.1.  Length.  – The length of the discharge hose  on a retail motor -fuel device:  
 
(a) shall be measured from its housing or outlet of the discharge line to the inlet of the discharge 
nozzle;  
 
(b) shall be measured with the hose fully extended if it is coiled or otherwise r etained or connected 
inside a housing; and  
 (c) shall not exceed 5.5  m (18  ft) unless it can be demonstrated that a longer hose is essential to 
permit deliveries to be made to receiving vehicles or vessels.  
 An unnecessarily remote location of a device shall not be accepted as justification for an abnormally long 
hose.  
(Amended 1972 and 1987)  
 
UR.1.1.2.  Marinas and Airports.  
 
UR.1.1.2.1.  Length.  – The length of the discharge hose  shall be as short as practicable, and shall 
not exceed  15 m (50  ft) unless it can be demonstrated that a longer hose is essential.  
 
UR.1.1.2.2.  Protection.  – Discharge hoses  exceeding 8  m (26  ft) in length shall be adequately 
protected from weather and other environmental factors when not  in use.  
(Made retroactive 1974 and Amended 1984)  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Manufacturer’s Instructions.  – A device shall be installed in accordance with the manufacturer’s 
instructions, and the installation shall be sufficiently secure and rigid to maintain this condition.  
(Added 1987)  
 
UR.2.2.  Discharge Rate.  – A device shall be installed so that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  Automatic  means for flow regulation shall be incorporated in the 
installation if necessary.  
 UR.2.3.  Suction Head.  – A piston -type device shall be installed so that the total effective suction head will 
not be great enough to cause vaporization of the liquid being dispensed under the highest temperature and lowest barometric pressure likely to occur . 
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 UR.2.4.  Diversion of Liquid Flow.  – A motor -fuel device  equipped with two delivery outlets used exclusively 
in the fueling of trucks shall be so installed that any diversion of flow to other than the receiving vehicle cannot be 
readily accomplished and is readily apparent.  Allowable deterrents include, but are not limited to, physical barriers 
to adjacent driveways, visible valves,  or lighting systems that indicate which outlets are in operation, and 
explanatory signs.  
(Amended 1991)  
 
UR.2.5.  Product Storage Identification.  
 
(a) The fill connection for any petroleum product storage tank or vessel supplying motor -fuel devices  shall 
be permanently, plainly, and visibly marked as to product contained.  
 
(b) When the fill connection device is marked by means of a color code, the color code key shall be conspicuously displayed at the place of business.  
(Added 1975) (Amended 1976)  
 
UR.3.  Use of Device.  
 
UR.3.1.  Return of Indicating and Recording Elements to Zero.  – On any dispenser used in making retail 
deliveries, the primary indicating element,  and recording element  if so equipped, shall be returned to zero 
before each delivery.  
 
Exceptions to this requirement are totalizers  on key- lock-operated or other self -operated dispensers and the 
primary recording element  if the device is equipped to record.  
 
UR.3.2.  Unit Price and Product Identity . 
 
(a) The following information shall be conspicuously displayed or posted on the face of a retail dispenser 
used in direct sale:  
 
(1) except for unit prices resulting from any post -delivery discount and dispensers used exclusively 
for fleet sales , other price contract sales , and truck refueling  (e.g., truck stop dispenser s used only 
to refuel trucks), all of the unit prices  at which the product is offered for sale; and  
 
(2) in the case of a computing type or money -operated type, the unit price at which the dispenser is set 
to compute.  
 
Provided that the dispenser complies with S.1.6.4.1. Display of Unit Price, it is not necessary that all the unit 
prices  for all grades, brands, blends , or mixtures be simultaneously displayed or posted.  
 
(b) The following info rmation shall be conspicuously displayed or posted on each side of a retail dispenser 
used in direct sale:  
 
(1) the identity of the product in descriptive commercial terms; and  
 
(2) the identity of the grade,  brand, blend,  or mixtur e that a multi- product dispenser is set to deliver.  
(Amended 1972, 1983, 1987, 1989, 1992, 1993, and 2012)  
 
UR.3.3.  Computing Device.  – Any computing device  used in an application where a product or grade  is 
offered for sale at one or more unit prices  shall be used only for sales for which the device computes and 
displays the sales price for the selected transaction.  
(Became retroactive 1999)  
(Added 1989) (Amended 1992)  
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 The following exceptions apply:  
 
(a) Fleet sales and other price contract sales are exempt from this requirement.  
 
(b) A truck stop dispenser used exclusively for refueling trucks is exempt from this requirement provided 
that: 
 
(1) all purchases of fuel are ac companied by a printed receipt of the transaction containing the 
applicable price per gallon, the total gallons delivered, and the total price  of the sale; and  
(Added 1993)  
 (2) unless  a dispenser complies with S.1.6.4.1. Display of Unit Price , the price posted on the dispenser 
and the price at which the dispenser is set to compute shall be the highest price for any transaction which may be conducted.  
(Added 1993)  
 
(c) A dispenser used in an application where a price per unit discount is offered following the delivery is exempt from this requirement, provided the following conditions are satisfied:  
 
(1) the unit price posted on the dispenser and the unit price at which the d ispenser is set to compute 
prior to the application of any discount shall be the highest unit price for any transaction;  
(Amended 2014)  
 
(2) all purchases of fuel are accompanied by a receipt recorded by the system.  The receipt shall 
contain:  
 
a.  the produc t identity  by name, symbol, abbreviation, or code number;  
 
b.  transaction  information as shown on the dispenser at the end of the delivery and prior to any 
post-delivery discount including the:  
 
1. total volume of the delivery;  
 
2. unit price; and  
 
3. total computed price of the fuel sale prior to post -delivery discounts being applied.  
 
c. an itemization of the post -delivery discounts to the unit price; and   
 
d. the final total price of the fuel sale.  
(Added 2012) (Amended 2014)  
(Added 1989) (Amended 1992, 1993, 2012, and 2014)  
 
UR.3.4.  Printed Ticket.  – The total price,  the total volume of the delivery, and the price per liter or gallon 
shall be shown, either printed by the device or in clear hand script, on any printed ticket  issued by a device and 
containing any one of these values.  
(Amended 2001)  
 UR.3.5.  Steps after Dispensing.  – After delivery to a customer from a retail motor -fuel device : 
 
(a) the starting lever shall be returned to its shutoff position and the zero -set-back interlock  engaged; and  
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 (b) the discharge nozzle shall be returned to its designed hanging position unless the primary indicating 
elements,  and recording elements,  if the device is equipped and activated to record, have been returned 
to a definite zero indication.  
 
UR.3.6.  Temperature Compensation, Wholesale.  
 
UR.3.6.1.  Automatic.  
 
UR.3.6.1.1.  When to be Used.  – If a device is equipped with a mechanical automatic temperature 
compensator, it shall be connected, operable, and in use at all times.  An electroni c or mechanical 
automatic temperature- compensating system may not be removed, nor may a compensated device be 
replaced with an uncompensated device, without the written approval of the responsible weights and 
measures jurisdiction.  
 
Note :  This requirement  does not specify the method of sale for product measured through a meter.  
(Amended 1989)  
 
UR.3.6.1.2.  Invoices.  
 
(a) A written invoice based on a reading of a device that is equipped with an automatic  
temperature compensator shall show that the volume delivered has been adjusted to the 
volume at 15 °C (60  °F). 
 
(b) The invoice issued from an electronic wholesale device equipped with an automatic  
temperature -compensating system shall als o indicate:  
 
(1) the API gravity, specific gravity or coefficient of expansion for the product;  
 
(2) product temperature; and  
 (3) gross reading.  
(Amended 1987)  
 
UR.3.6.2.  Nonautomatic . 
 
UR.3.6.2.1.  Temperature Determination.  – If the volume of the product delivered is adjusted to 
the volume at 15  °C (60  °F), the product temperature shall be taken during the delivery in:  
 
(a) the liquid chamber of the meter; or  
 
(b) the meter inlet or discharge lin e adjacent to the meter; or  
 
(c) the compartment of the receiving vehicle at the time it is loaded.  
 
UR.3.6.2.2.  Invoices.  – The accompanying invoice shall indicate that the volume of the product has 
been adjusted for temperature variations to a volume at 15  °C (60  °F) and shall also state the product 
temperature used in making the adjustment.  
 
UR.3.6.3.  Period of Use. –  When f uel is bought or sold on an automatic  or non-automatic  
temperature -compensated basis, it shall be bought or sold using this method over at least a consecutive 
12-month period, unless otherwise agreed to by both the buyer and seller in writi ng. 
(Added 2003)  
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 Section 3.31.  Vehicle -Tank Meters  
 
 
A. Application  
 
A.1. General.  – This code applies to meters mounted on vehicle tanks including those used for the measurement 
and delivery of petroleum products or agri -chemical liquids such as fertilizers, feeds, pesticides, defoliants, and bulk 
deliveries of water.  
(Amended 1985 and 1995)  
 A.2. Exceptions.  – This code does not apply to the following devices:  
 
(a) Devices used for dispensing liquefied petroleum gases, or other liquids that do not remain in a  liquid state 
at atmospheric pressures and temperatures. (Also see Section  3.32. Code for Liquefied Petroleum Gas and 
Anhydrous Ammonia Liquid- Measuring Devices.)  
 (b) Devices used solely for dispensing a product in connection with operations in which the amount dispensed 
does not affect customer charges.  
 
(c) Vehicle tanks used as measures.  (Also see Section  4.40. Code for Vehicle Tanks Used as Measures.)  
 
(d) Mass flow meters.  (Also see Section  3.37. Code for Mass Flow Meters.)  
(Added 1994)  
 
(e) Devices used to measure cryogenic liquids.  (Also see Section 3.34. Code for Cryogenic Liquid- Measuring 
Devices.)  
 
(f) Devices used to measure carbon dioxide liquids.  (Also see Section 3.38. Code for Carbon Dioxide Liquid -Measuring Devices.)  
 
A.3. Additional Code Requir ements.  – In addition to the requirements of this code, Vehicle -Tank Meters shall 
meet the requirements of 1.10. General Code requirements.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A meter shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  
 
Note:   Except for systems used solely for the sale of aviation fuel into aircraft and for aircraf t-related operations, 
vehicle -tank meters shall be equipped with a primary recording element as required by paragraph UR.2.2. Ticket 
Printer; Customer Ticket.  
(Amended 1993)  
 
S.1.1.2.  Units.  
 
(a) A meter shall indicate, and record if the meter is equipped to record, its deliveries in terms of liters 
or gallons.  Fractional parts of the liter or gallon shall be in terms of either decimal or binary 
subdivisions.  
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 (b) When it is an industry practice to purchase and sell milk by weight based upon 1.03 kg/L 
(8.6 lb/gal), the primary indicating element may indicate in kilograms or pounds and decimal 
kilograms or pounds.  The weight value division shall be a decimal multiple or submultiple of 1, 2, 
or 5.  (Also see  Section S.5.5. Conversion Factor.)  
 
S.1.1.3.  Valu e of Smallest Unit.  – The value of the smallest unit of indicated delivery, and recorded 
delivery if the meter is equipped to record, shall not exceed the equivalent of:  
 
(a) 0.5 L (0.1  gal) or 0.5  kg (1  lb) on milk -metering systems;  
 (b) 0.5 L (0.1  gal) on meters with a rated maximum flow rate of 750  L/min (200 gal/min) or less;  
 
(c) 5 L (1 gal) on meters with a rated maximum flow of 375  L/min (100 gal/min) or more used for jet 
fuel aviation refueling systems; or  
 (Added 2006)  
 
(d) 5 L (1 gal) on other meters . 
(Amended 1989, 1994 and 2006)  
 
S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only by the mechanical operation of the meter.  However, a 
meter may be cleared by advancing its elements to zero, but only if:  
 
(a) the advancing movement, once started, cannot be stopped until zero is reached; or  
 
(b) in the case of indicating elements only, such elements are automatically obscured until the 
elements reach the correct zero position.  
 
S.1.1.5.  Return to Zero.  – Primary indicating elements shall be readily returnable to a definite zero 
indication.  Means sh all be provided to prevent the return of primary indicating elements, and of primary 
recording elements if these are returnable to zero, beyond their correct zero position.  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the  width of main graduations shall be 
not more than 50  % greater than the width of subordinate graduations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) wide.  
 S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall be not les s than 2.5  mm 
(0.10  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the indicator is continuous, at the point of widest separ ation of the graduations.  
(Amended 1986)  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations at 
least throughout that portion of its length associated with the graduations.  
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 S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than:  
 
(a) the width of the narrowest graduation ;* and  
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 
(b) the width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 S.1.3.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.1.3.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
S.1.3.6.  Travel of Indicator.  – If the most sensitive element of the primary indicating element utilizes 
an indicator and g raduations, the relative movement of these parts corresponding to the smallest indicated 
value shall not be less than 5  mm (0.20 in). 
 
S.1.4.  Computing -Type Device.  
 
S.1.4.1.  Display of Unit Price.  – In a device of the computing type, means shall be provided for 
displaying, in a manner clear to the operator and an observer, the unit price at which the device is set to 
compute.  The unit price is not required to be displayed continuously.  
(Amended 1983 and 2005)  
 
S.1.4.2.  Printed Ticket.  – If a computing -type device issues a printed ticket which displays the total 
computed price, the ticket shall also have printed clearly thereon  the total quantity of the delivery, the 
appropriate fraction of the quan tity, and the price per unit of quantity.  
(Amended 1989)  
 
S.1.4.3.  Money -Value  Computations.  – Money- value computations shall be of the full- computing type 
in which the money- value at a single unit price, or at each of a series of unit prices, shall be computed for 
every delivery within either the range of measurement of the device or the range o f the computing 
elements, whichever is less.  Value graduations shall be supplied and shall be accurately positioned.  The 
value of each graduated interval shall be one cent.  On electronic devices with digital indications, the total 
price may be computed on the basis of the quantity indicated when the value of the smallest division 
indicated is equal to or less than 0.2  L (0.1  gal) or 0.2  kg (1  lb). 
(Amended 1979 and 1989)  
 
S.1.4.4.  Money -Values, Mathematical Agreement. – Any digital money -value indication  and any 
recorded money -value on a computing -type device shall be in mathematical agreement with its associated 
quantity indication or representation to within one  cent of money- value.  
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 S.2. Design of Measuring Elements.  
 
S.2.1.  Vapor Elimination.  – A mete ring system shall be equipped with an effective vapor or air eliminator 
or other automatic means to prevent the passage of vapor and air through the meter.  Vent lines from the air or 
vapor eliminator shall be made of metal tubing or some other suitable ri gid material.  
(Amended 1993)  
 
S.2.2.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before a change or an adjustment  or interchange m ay be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries; and  
 (c)  any metrological parameter that will affect the metrological integrity o f the device or system.  
 
When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
[Audit trails shall use the format set forth in Table  S.2.2. Categories of Device and Methods Sealing. ]* 
[*Nonretroactive as of January  1, 1995]  
(Amended 2006)  
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 Table S.2.2.  
Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for  configuration 
parameters.  
Category  2:  Remote configuration capability, but access 
is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  The hardware enabling access for remote communication 
must be on -site.  The hardware must be sealed using a 
physical seal or an event counter for calibration 
parameters an d an event counter for configuration 
parameters.  The event counters may be located either at the individual measuring device or at  
the system 
controller; however, an adequate number of counters 
must be provided to monitor the calibration and 
configuration parameters of the individual devices at a 
location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of the 
information through an on -site device.  
Category  3:  Remo te configuration capability access may 
be unlimited or controlled through a software switch 
(e.g., password) . 
 
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  
 An event logger is required in the device; it must include 
an event counter (000 to 999), the parameter ID, the date 
and time of the change, and the new value of the 
parameter.  A printed copy of the information must be 
available through the device or through another on -site 
device.  The event logger shall have a capacity to retain records equal to 10 times the number of sealable  
parameters in the device, but not more than 1000 records 
are required.  ( Note:   Does not r equire 1000 changes to 
be stored for each parameter.)  
[Nonretroactive  as of January  1, 1995]  
(Table Added 2006)  
 
S.2.3.  Directional Flow Valves.  – Valves intended to prevent reversal of flow shall be automatic in 
operation.  However, on equipment used exclusively for fueling aircraft, such valves may be manual in 
operation.  
 
S.2.4.  Zero -Set-Back Interlock, Vehicle -Tank Meters, Electronic.  – Except  for vehicle -mounted metering 
systems used solely for the delivery of aviation fuel, a device shall be so constructed that after an individual or multiple deliveries at one location have been completed, an automatic interlock system shall engage to prevent  
a subsequent delivery until the indicating and, if equipped, recording elements have been returned  to their zero 
position.  For individual deliveries, if there is no product flow for three  minutes the transaction must be 
completed before additional produc t flow is allowed.  The 3 -minute timeout shall be a sealable  feature on an 
indicator.  
[Nonretroactive  as of January  1, 2006]  
(Added 2005)  
 
S.2.5.  Automatic Temperature Compensation for Refined Petroleum Products.  
 
S.2.5.1.  Automatic Temperature Compensation for Refined Petroleum Products.  – A device may 
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 of product to the volume at 15 °C for liters  or the volume at 60 °F for gallons and decimal  subdivisions or 
fractional equivalents thereof where not prohibited by state law.  
 S.2.5.2.  Provision for Deactivating. –  On a device equipped with an automatic temperature-
compensating mechanism that will indicate or record only in terms of liters compen sated to 15°C or gallons 
compensated to 60 °F, provision shall be made for deactivating the automatic temperature -compensating 
mechanism so the meter can indicate and record, if it is equipped to record, in terms of the uncompensated 
volume.  
 
S.2.5.3.  Gros s and Net Indications.  – A device equipped with automatic temperature compensation 
shall indicate or record, if equipped to record, both the gross (uncompensated) and net (compensated) 
volume for testing purposes.  It is not necessary that both net and gross volume be displayed 
simultaneously.  
 S.2.5.4.  Provision for Sealing Automatic Temperature -Compensating Systems.  – Adequate 
provision shall be made for an approved means of security (e.g., data change audit trail) or physically 
applying security seals in  such a manner that an automatic temperature -compensating system cannot be 
disconnected and no adjustment may be made to the system.  
 
S.2.5.5.  Temperature Determination with Automatic Temperature Compensation.  – For test 
purposes, means shall be provided ( e.g., thermometer well) to determine the temperature of the liquid 
either:  
 
(a) in the liquid chamber of the meter; or  
 (b) immediately  adjacent to the meter in the meter inlet or discharge line.  
(Added 2007)  
 
S.2.6.  Thermometer Well, Temperature Determination.   For test purposes, means shall be provided 
(e.g., thermometer well) to determine the temperature of the liquid either in the:  
 
(a)  liquid  chamber of the meter; or  
 (b) meter  inlet or discharge line immediately adjacent to the meter.  
 [Nonretroactive  as of January 1, 2012)  
 (Added 2011)  
 
S.3. Design of Discharge Lines and Discharge Line Valves.  
(Not applicable to milk -metering systems.)  
 
S.3.1.  Diversion of Measured Liquid.  – Except on equipment used exclusively for fueling aircraft, no 
means shall be provided by which any measured liquid can be diverted from the measuring chamber of the 
meter or the discharge line thereof.  However, two or more delivery outlets may be insta lled if means is 
provided to insure that:  
 
(a) liquid  can flow from only one such outlet at one time; and  
 (b) the direction of flow for which the mechanism may be set at any time is definitely  and conspicuously 
indicated.  
 
S.3.2.  Pump -Discharge Unit.  – On a p ump-discharge unit, the discharge hose shall be of the wet -hose type 
with a shutoff valve at its outlet end.  However, a pump -discharge unit may be equipped also with a dry -hose 
without a shutoff valve at its outlet end, but only if:  
 
(a) the dry-hose is a s short as practicable; and  Handbook 44 –  20152016   3.31.  Vehicle -Tank Meters  
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(b) there  is incorporated in the discharge piping, immediately adjacent to the meter, effective means to 
insure that liquid  can flow through only one of the discharge hoses at any one time and that the meter 
and the wet -hose remain full of liquid at all times.  
 
S.3.3.  Gravity- Discharge Unit.  – On a gravity- discharge unit, the discharge hose or equivalent pipe shall be 
of the dry -hose type with no shutoff valve at its outlet end.  The dry- hose shall be of such stiffness and onl y of 
such length as to facilitate its drainage.  The inlet end of the hose or of an equivalent outlet pipe shall be of such 
height as to provide for proper drainage of the hose or pipe.  There shall be incorporated an automatic vacuum 
breaker or equivalent  means to prevent siphoning and to e nsure the rapid and complete drainage.  
 
S.3.4.  Discharge Hose.  – A discharge hose shall be adequately reinforced.  
 S.3.5.  Discharge Valve.  – A discharge valve may be installed in the discharge line only if the device is of the 
wet-hose type, in which case such valve shall be at the discharge end of the line.  Any other shutoff valve on the 
discharge side of the meter shall be of the automati c or semiautomatic predetermined -stop type or shall be 
operable only:  
 
(a) by means of a tool (but not a pin) entirely separate from the device; or  
 (b) by mutilation of a security seal with which the valve is sealed open.  
 
S.3.6.  Antidrain Valve.  – In a w et-hose, pressure -type device, an effective antidrain  valve shall be 
incorporated in the discharge valve or immediately adjacent thereto.  The antidrain  valve shall function so as to 
prevent the drainage of the discharge hose.  However, a device used exclu sively for fueling and defueling  
aircraft may be of the pressure type without an antidrain  valve.  
 
S.4. Design of Intake Lines (for Milk -Metering Systems).  
 
S.4.1.  Diversion of Liquid to be Measured.  – No means shall be provided by which any liquid can be 
diverted from the supply tank to the receiving tank without being measured by the device.  
 
S.4.2.  Intake Hose.  – The intake hose shall be:  
 
(a) of the dry- hose type;  
 (b) adequately  reinforced;  
 
(c) not more than 6  m (20  ft) in length, unless it can be demonstrated that a longer hose is essential to 
permit pickups from a supply tank; and  
 (d) connected  to the pump at horizontal or above, to permit complete drainage of the hose.  
 
S.5. Marking Requirements.  
 
S.5.1.  Limitation of Use.  – If a meter is intended to measure accurately only liquids having particular 
properties, or to measure accurately only under specific installation or operating conditions, or to measure 
accurately only when used in conjunction with specific accessory equ ipment, these limitations shall be clearly 
and permanently stated on the meter.  
 
S.5.2.  Discharge Rates.  – A meter shall be marked to show its designed maximum and minimum discharge 
rates.  However, the minimum discharge rate shall not exceed 20  % of the m aximum discharge rate.  
 
Note :  Also see example in Section  3.30. Liquid- Measuring Devices Code, paragraph  S.4.4.1. Discharge Rates.  
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S.5.3.  Measuring Components, Milk -Metering System.  – All components that affect the measurement of 
milk that are disassembled for cleaning purposes shall be clearly and permanently identified with a common 
serial number.  
 
S.5.4.  Flood Volume, Milk -Metering System.  – When applicable, the volume of product necessary to flood 
the system when dry shall be clearly, conspicuously, and permanently marked on the air eliminator.  
 
S.5.5.  Conversion Factor.  – When the conversion factor of 1.03 kg/L (8.6  lb/gal) is used to convert the 
volume of milk to weight, the con version factor shall be clearly marked on  the primary indicating element and 
recorded on the delivery ticket.  
(Added 1989)  
 
S.5.6.  Temperature Compensation for Refined Petroleum Products. –  If a device is equipped with an 
automatic temperature compensator, the primary indicating elements, recording elements, and recorded 
representations shall be clearly and conspicuously marked to show the volume delivered has been adjusted to 
the volume at  15 °C for liters or the volume at 60  °F for gallons and decimal subdivisions or fractional 
equivalents thereof.  
(Added 2007)  
 S.5.7.  Meter Size.  – Except for milk meters, if the meter model identifier does not provide a link to the meter 
size (in terms of  pipe diameter) on an NTEP Certificate of Conformance, the meter shall be marked to show 
meter size.  
[Nonretroactive as of January  1, 2009]  
(Added 2008)  
 
N. Notes  
 
N.1. Test Liquid.  
 
(a) A measuring system shall be tested with the liquid to be commercially  measured or with a liquid of the 
same general physical characteristics.  Following a satisfactory examination, the weights and measures 
official should attach a seal or tag indicating the product used during the test.  
(Amended 1975)  
 
(b) A milk -measuring system shall be tested with the type of milk to be measured when the accuracy of the 
system is affected by the characteristics of milk (e.g.,  positive displacement meters).  
(Added 1989)  
(Amended 1975 and 1989)  
 N.2. Evaporation and Volume Change.  – Care sh all be exercised to reduce to a minimum, evaporation losses 
and volume changes resulting from changes in temperature of the test liquid.  
 
N.3. Test Drafts.  – Test drafts should be equal to at least the amount delivered by the device in 1  minute at its 
maximum discharge rate, and shall in no case be less than 180  L (50  gal) or 225  kg (500  lb). 
(Amended 1989)  
 
N.4. Testing Procedures.  
 
N.4.1.  Normal Tests.  – The “normal” test of a measuring system shall be made at the maximum discharge 
rate that may be anticipated under the conditions of the installation.  Any additional tests conducted at flow 
rates down to and including one -half of the sum of the maximum disc harge flow rate and the rated minimum 
discharge flow rate shall be considered normal tests.  
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N.4.1.1.  Milk Measuring System.  – The “normal” test shall include a determination of the effectiveness 
of the air elimination system.  
 
N.4.1.2.  Repeatability  Tests. – Tests for repeatability  should include a minimum of three consecutive 
test drafts of approximately the same size and be conducted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not aff ect the 
results obtained.  
(Added 2001)  
 
N.4.1.3.  Automatic  Temperature- Compensating Systems for Refined Petroleum Products.  – On 
devices equipped with automatic temperature -compensating systems, normal tests shall be conducted:  
 
(a) by comparing the compensated volume indicated or recorded to the actual delivered volume 
corrected to 15  °C for liters or 60  °F for gallons and decimal subdivisions or fractional equivalents 
thereof; and  
 
(b) with the temperature -compensating system deactivated, comparing the uncompensated volume 
indicated or recorded to the actual delivered volume.  
 The first test shall be performed with the automatic temperature -compensating system operating in the 
“as-found” condition.  On devices that indicate or record both the compensated and uncom pensated volume 
for each delivery, the tests in (a) and (b) may be performed as a single test.  
(Added 2007)  
 
N.4.2.  Special Tests (Except Milk -Measuring Systems).  – “Special” tests shall be made to develop the 
operating characteristics of a measuring system and any special elements and accessories attached to or 
associated with the device.  Any test except as set forth in N.4.1. Normal Tests and N.4.5. Product Depl etion 
Test shall be considered a special test.  Special tests of a measuring system shall be made at a minimum 
discharge rate of 20  % of the marked maximum discharge rate or at the minimum discharge rate marked on the 
device, whichever is less.  
(Amended 1978 and 2005)  
 
N.4.3.  Antidrain Valve Test.  – The effectiveness of the antidrain  valve shall be tested after the pump 
pressure in the measuring system has been released and a valve between the supply tank and the discharge valve 
is closed.  
 
N.4.4.  System Ca pacity.  – The test of a milk -measuring system shall include the verification of the volume 
of product necessary to flood the system as marked on the air eliminator.  
 
N.4.5.  Product Depletion Test.  – Except for vehicle -mounted metering systems used solely f or the delivery 
of aviation fuel, the effectiveness of the vapor eliminator or vapor elimination means shall be tested by 
dispensing product at the normal flow rate until the product supply is depleted and continuing until the lack of 
fluid causes the meter indication to stop completely for at least 10  seconds.  If the meter indication fails to stop 
completely for at least 10  seconds, continue to operate the system for 3  minutes.  Finish the test by switching to 
another compartment with sufficient product to complete the test on  a multi -compartment vehicle or by adding 
sufficient product to complete the test to  a single compartment vehicle.  When adding product to a single 
compartment vehicle, allow appropriate time for any entrapped vapor to disperse before  continuing the test.  
Test drafts shall be of the same size and run at approximately the same flow rate.  
(Added 2005)  
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 N.5. Temperature Correction for Refined Petroleum Products.  – Corrections shall be made for any changes in 
volume resulting from the dif ferences in liquid temperatures between the time of passage through the meter and the 
time of volumetric  determination in the prover.  When adjustments are necessary, appropriate petroleum 
measurement tables should be used.  
(Added 2007)  
 
T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Underregistration and to Overregistration.  – The tolerances hereinafter prescribed shall be 
applied to errors of underregistration and errors of overregistration.  
 
T.2. Tolerance Values.  – Tolerances shall be as shown in Table 1. Accuracy Classes and Tolerances for Vehicle -
Tank Meters and Table 2. Tolerances for Vehicle -Mounted Milk Meters.  
(Amended 1995)  
 
 
Table 1.  
Accuracy Classes and Tolerances for Vehicle -Tank Meters  
Accuracy 
Class  Application  Acceptance 
Tolerance  Maintenance 
Tolerance  Special Test 
Tolerance  
0.3 - Petroleum products delivered from large capacity (flow 
rates over 115  L/min or 30 gpm)** devices, including 
motor -fuel devices  
- Heated products (other than asphalt) at temperatures 
greater than 50  °C (122 °F) 
- Asphalt at temperatures equal to or below 50  °C 
(122 °F) 
- All other liquids not shown in the table where the 
typical delivery is greater than 200  L (50  gal) 0.15 %  0.3 %  0.45 %  
0.3A  - Asphalt at temperatures greater than 50  °C (122  °F) 0.3 %  0.3 %  0.5 %  
0.5* - Petroleum products delivered from small capacity (at 
4 L/min (1  gpm) through 115 L/min or 30 gpm)** 
motor -fuel devices  
- Agri-chemical liquids  
- All other applications not shown in the table where the 
typical delivery is ≤  200 L (50  gal) 0.3 %  0.5 % 0.5 %  
1.1 - Petroleum products and other normal liquids from 
devices with flow rates** less than 4  L/min (1  gpm) 
and 
- Devices designed to deliver less than 4  L (1 gal) 0.75 %  1.0 %  1.25 %  
1.5 - Water  Overregistration  1.5 %  1.5 %  1.5 %  
Underregistration  1.5 %  1.5 %  5.0 %  
*  For 5  gal and 10  gal test drafts, the tolerances specified for Accuracy Class  0.5 in the table above do not apply.  For 
these test drafts, the maintenance tolerances on normal and special tests for 5  gal and 10  gal test drafts are 6  in3 and 
11 in3, respectively.  Acceptance tolerances on normal and special tests are 3  in3 and 5.5 in3. 
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 Table 1.  
Accuracy Classes and Tolerances for Vehicle -Tank Meters  
Accuracy 
Class  Application  Acceptance 
Tolerance  Maintenance 
Tolerance  Special Test 
Tolerance  
(Added 2002) (Amended 2013)  
 
Table 2.   
Tolerances for Vehicle -Mounted Milk Meters  
Indication  
(gallons)  Maintenance Tolerance  
(gallons)  Acceptance  Tolerance  
(gallons)  
100 0.5 0.3 
200 0.7 0.4 
300 0.9 0.5 
400 1.1 0.6 
500 1.3 0.7 
Over 500  Add 0.002  gallon  per indicated gallon 
over 500  Add 0.001  gallon  per indicated gallon over 
500 
 (Added 1989)  
 
T.2.1.  Automatic Temperature- Compensating Systems. –  The difference between the meter error 
(expressed as a percentage) for results determined with and without the automatic temperature- compensating 
system activated shall not exceed:  
 
(a) 0.2 % for mechanical automatic temperature -compensating systems; and  
 
(b) 0.1 % for electronic automatic temperature -compensating systems.  
 
The delivered quantities for each test shall be approximately the same size.  The results of each test shall be 
within the applicable acceptance or maintenance tolerance.  
(Added 2007) (Amended 2010)  
 
T.3. Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within the applicable tolerance.  (Also see N.4.1.2. Repeatability Tests.)  
(Added 1992) (Amended 2001 and 2002)  
 
T.4. Product Depletion Test.  – The difference between the test result for any normal test and the product 
depletion test shall not exceed 0.5  % of the volume delivered in one minute at the maximum flow rate marked on the 
meter for meters rated higher than 380  Lpm (100 gpm) or 0.6  % of the volume delivered in one minute at the 
maximum flow rate marked on the meter for meters rated 380 Lpm (100  gpm) or lower.  Test drafts shall be of the 
same size and run at approximately the same flow rate.  
 
Note:   The result of the product depletion t est may fall outside of the applicable test tolerance as specified in Table 1. Accuracy 
Classes and Tolerances for Vehicle- Tank Meters.  
(Amended 2013)  
 
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 UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Discharge Rate.  – A meter shall be so installed that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  If necessary, means for flow regulation shall be incorporated in the 
installation, in which case this shall be fully effective and au tomatic in operation.  
 UR.1.2.  Unit Price.  – There shall be displayed on the face of a device of the computing type the unit price at 
which the device is set to compute.  
 UR.1.3.  Intake Hose.  – The intake hose in a milk -metering system shall be installed to permit complete 
drainage and ensure that all available product is measured following each pickup.  
 
UR.1.4.  Liquid Measured.  – A vehicle -tank meter shall continue to be used to measure the s ame liquid or 
one with the same general physical properties as that used for calibration and weights and measures approval 
unless the meter is recalibrated with a different product and tested by a registered service agency or a weights 
and measures official and approved by the weights and measures jurisdiction having statutory authority over the 
device.  
(Added 2003)  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements 
(visual), and the prim ary recording elements, when these are returnable to zero, shall be returned to zero 
immediately before each delivery is begun and after the pump has been activated and the product to be 
measured has been supplied to the measuring system.  
(Amended 1981)  
 UR.2.2.  Ticket Printer, Customer Ticket.  – Vehicle -Mounted metering systems shall be equipped with a 
ticket printer which shall be used for all sales where product is delivered through the meter.  A copy of the 
ticket issued by the device shall be left wit h the customer at the time of delivery or as otherwise specified by the 
customer.  
(Added 1993) (Amended 1994)  
 
UR.2.2.1.  Exceptions for the Sale of Aviation Fuel.  – The provisions of UR.2.2. Ticket Printer, 
Customer Ticket shall not apply to vehicle -mounte d metering systems used solely for the delivery of 
aviation fuel into aircraft and for aircraft -related operations.  
(Added 1999)  
 
UR.2.3.  Ticket in Printing Device.  – A ticket shall not be inserted into a device equipped with a ticket 
printer until immedia tely before a delivery is begun, and in no case shall a ticket be in the device when the 
vehicle is in motion while on a public street, highway, or thoroughfare.  
 
UR.2.4.  Credit for Flood Volume.  – The volume of product necessary to flood the system as marked on the 
air eliminator shall be individually recorded on the pickup ticket of each seller affected.  
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 UR.2.5.  Automatic Temperature Compensation for Refined Petroleum Products.  
 
UR.2.5.1.  When to be Used. –  In a state that does not prohibit, by law or regulation, the sale of 
temperature -compensated product, a device equipped with an activated automatic- temperature compensator 
shall be connected, operable, and in use at all times.  An electronic or mechanical automatic 
temperature -compensating device or system may not be removed or deactivated, nor may a compensated 
device be replaced with an uncompensated device or system, without the written approval of the 
responsible weights and measures juris diction.  
 
Note:   This requirement does not specify the method of sale for products measured through a meter.  
(Amended 2009)  
 
UR.2.5.2.  Period  of Use. –  When fuel is bought or sold on an automatic temperature compensation 
basis, it shall be bought or sold using this basis over at least a consecutive 12- month period unless 
otherwise agreed to by both the buyer and seller in writing.  
(Added 2009)  
 UR.2.5.3.  Invoices.  – An invoice based on a reading of a device that is equipped with an automatic 
temperature compensator shall show that the volume delivered has been adjusted to the volume at 15  °C for 
liters or the volume at 60  °F for gallons and decimal subdiv isions or fractional equivalents thereof.  
(Added 2007)  
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 Section 3.32.  Liquefied Petroleum Gas and Anhydrous Ammonia  
Section 3.32.  Liquefied Petroleum Gas and Anhydrous Ammonia  
Liquid -Measuring Devices39 
 
 
A. Application.  
 
A.1. General.  – This code applies to devices used for the measurement of liquefied petroleum gas and anhydrous 
ammonia in the liquid state, whether such devices are installed in a permanent location or mounted on a vehicle.  
 
A.2. Devices Used to Measure Other Liquid Products not Covered in Specific Codes.  – Insofar as they are 
clearly appropriate, the requirements and provisions of the code may be applied to devices used for the measurement of other liquids that do not remain in a liquid state at atmospheric pressures a nd temperatures.  
 
A.3. Exceptions . – This code does not apply to mass flow meters.  (Also see Section 3.37. Code for Mass Flow 
Meters.)  
(Added 1994)  
 A.4. Additional Code Requirements.  – In addition to the requirements of this code, LPG and Anhydrous 
Ammon ia Liquid -Measuring Devices shall meet the requirements of Section 1.10. General Code.  
 
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A device shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  
 
Note :  Vehicle -mounted metering systems shall be equipped with a primary recording element as required by 
paragraph UR.2.6. Ticket P rinter; Customer Ticket.  
 S.1.1.2.  Units.  – A device shall indicate, and record if the device is equipped to record, its deliveries in 
terms of liters, gallons, quarts, pints, or binary -submultiple or decimal subdivisions of the liter or gallon.  
(Amended 1 987) 
 S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated delivery, and recorded 
delivery if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) 0.5 L (1 pt) on retail devices; or  
 (b) 5 L (1 gal) on wholesale devices.  
(Amended 1987)  
 
                                                           
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 S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only by the mechanical operation of the device.  However, a 
device may be cleared by advancing its elements to zero, but only if:  
 
(a) the advancing movement, once started, cannot be stopped until zero is reached; or  
 
(b) in the case of indicating elements only, such elements are automatically obscured until the 
elements reach the correct zero position.  
 
S.1.1.5.  Money -Values, Mathematical Agreement.  – Any digital money -value indication and any 
recorded money -value on a computing -type device shall be in mathematical agreement with its associated 
quantity indication or representation  to within 1  cent of money- value; except that a stationary retail 
computing -type device must compute and indicate to the nearest 1  cent of money- value.  (Also see 
Section  1.10.  General Code, G -S.5.5. Money -Values, Mathematical Agreement.)  
(Amended 1984 and 1988)  
 
S.1.1.6.  Printed Ticket.  – Any printed ticket issued by a device of the computing type on which there is 
printed the total computed price, shall have printed clearly thereon the total volume of the delivery in terms 
of liters or gallons, and the ap propriate decimal fraction of the liter or gallon, and the corresponding price 
per liter or gallon.  
(Added 1979) (Amended 1987)  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 
S.1.2.2.  Width.  – In any series of graduations:  
 
(a) the width of a graduation shall in no case be greater than the width of the minimum clear interval 
between graduations;  
 
(b) the width of main graduations shall be not more than 50  % greater than the width of subordinate  
graduations .  Graduations ;  and  
 
(b)(c)  graduations  shall in no case be less than 0.2  mm (0.008 in) in width.  
 
S.1.2.3.  Clear Interval between Graduations.  – The clear interval shall be not less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 
(b) if the indicator is co ntinuous, at the point of widest separation of the graduations.  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the gra duations.  
 
S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of graduations, shall be not more 
than 1.0  mm (0.04  in). 
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 S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than:  
 
(a) the width of the narrowest graduation;* and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 
(b) the width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 
S.1.3.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 S.1.3.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
S.1.4.  For Retail Devices Only.  
 
S.1.4.1.  Indication of Delivery.  – A retail device shall be constructed to show automatica lly its initial 
zero condition and the amounts delivered up to the nominal capacity of the device.  
 
S.1.4.2.  Return to Zero.  
 
(a) Primary indicating elements shall be readily returnable to a definite zero indication.  
 
(b) Primary recording elements on a stationary retail device shall be readily returnable to a definite 
zero indication if the device is equipped to record.  
 
(c) Means shall be provided to prevent the return of primary indicating elements and of primary recording elements if these are returnable to zero, beyond their correct zero position.  
(Amended 1990)  
 
S.1.5.  For Stationary Retail Devices Only.  
 
S.1.5.1.  Display of Unit Price and Product Identity.  – In a device of the computing type, means shall 
be provided for displaying on each face of the device the unit price at which the device is set to compute or 
to deliver as the case may be, and there shall be conspicuously displayed on each side of the device the 
identity of the product that is being dispensed.  If a device is so designed as to dispense more than one grade, brand, blend, or mixture of product, the identity of the grade, brand, blend, or mixture being 
dispensed shall also be displayed on ea ch face of the device.  
 
S.1.5.2.  Money -Value Computations.  – A computing device shall compute the total sales price at any 
single -purchase unit price (excluding fleet sales and other price contract sales) for which the product is 
offered for sale at any de livery possible within either the measurement range of the device or the range of 
the computing elements, whichever is less.  The analog money- value indication shall not differ from the 
mathematically computed money -value (quantity × unit price = sales pri ce), for any delivered quantity, by 
an amount greater than the values shown in Table  1. Money -Value Divisions and Maximum Allowable 
Variations for Money -Value Computations on Mechanical Analog Computers.  
(Amended 1995)  
 
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 Table 1.  
Money -Value Divisions and  
Maximum Allowable Variations for Money- Value  
Computations on Mechanical Analog Computers  
Unit Price  Money - 
Value  
Division  Maximum  
Allowable Variation  
From  To and Including  Design  
Test Field  
Test 
0 $0.25/liter or  
$1.00/gallon  1¢ ± 1¢ ± 1¢ 
$0.25/liter or 
$1.00/gallon   $0.75/liter or  
 $3.00/gallon 1¢ or 2¢  ± 1¢ ± 2¢ 
$0.75/liter or  
$3.00/gallon        $2.50/liter or  
    $10.00/gallon 1¢ or 2¢  ± 1¢ ± 2¢ 
$0.75/liter or  
$3.00/gallon        $2.50/liter or  
    $10.00/gallon 5¢ ± 2½¢  ± 5¢ 
 
S.1.5.2.1.  Money -Value Divisions, Analog.  – The value of the graduated intervals representing 
money -values on a computing -type device with analog indications shall be as follows:  
 
(a) Not more than 1  cent at all unit prices up to and including $0.25 per liter or $1.00  per gallon.  
 
(b) Not more than 2  cents at unit prices greater than $0.25  per liter or $1.00 per gallon up to and 
including $0.75 per liter or $3.00 per gallon.  
 (c) Not more than 5  cents at all unit prices greater than $0.75  per liter or $3.00  per gallon . 
(Amended 1984)  
 
S.1.5.2.2.  Money -Value Divisions, Digital.  – A computing -type device with digital indications 
shall comply with the requirements of paragraph  G.-S.5.5. Money -Values, Mathematical Agreement, 
and the total price computation shall be based o n quantities not exceeding 0.01 gal intervals for devices 
indicating in U.S. customary units and 0.05  L for devices indicating in metric units.  
 
S.1.5.2.3.  Money- Value Divisions, Auxiliary Indications.  – In a system equipped with auxiliary 
indications, all  indicated money -value divisions shall be identical.  
[Nonretroactive as of January  1, 1985.]  
 
S.1.5.3.  Recorded Representations, Point -of-Sale Systems.  – Except for fleet sales and other price 
contract sales, a printed receipt providing the following information shall be available through a built -in or 
separate recording element for all transactions conducted with point -of-sale systems or devices activat ed by 
debit cards, credit cards, and/or cash:  
 
(a) the total volume of the delivery;  
 
(b) the unit price;  
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 (c) the total computed price; and  
 
(d) the product identity by name, symbol, abbreviation, or code number.  
(Added 2014)  
 
S.1.6.  For Wholesale Devices  Only.  
 
S.1.6.1.  Travel of Indicator.  – A wholesale device shall be readily operable to deliver accurately any 
quantity from 180  L (50  gal) to the capacity of the device.  If the most sensitive element of the indicating 
system uses an indicator and graduations, the relative movement of these parts corresponding to a delivery 
of 5 L (1 gal) shall be not less than 5  mm (0.20  in). 
(Amended 1987)  
 
S.2. Design of Measuring Elements.  
 
S.2.1.  Vapor Elimination.  – A device shall be equipped with an effective vapor eliminator or other 
effective means t o prevent the passage of vapor through the meter.  
 
S.2.2.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before an adjustment or interchange may be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element for controlling delivery rate, when such rate tends to affect the accuracy of deliveries; and  
 
(c) any metrological parameter that will affect the metrological integrity of the device or system.  
 
When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 
[Audit trails shall use the format set forth in Tab le S.2.2. Categories of Device and Methods of Sealing.]*  
[*Nonretroactive as of January  1, 1995]  
(Amended 2006)  
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 Table S.2.2.  
Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two  event counters:  one for 
calibration parameters and one for configuration 
parameters.  
Category  2:  Remote configuration capability, but access 
is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable of printing in this mode or shall not operate while in this 
mode.  The hardware enabling access for remote 
communication must be on- site.  The hardware must be 
sealed using a phy sical seal or an event counter for 
calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or at 
the system controller; however, an adequate number of 
counters m ust be provided to monitor the calibration 
and configuration parameters of the individual devices at a location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of t he 
information through an on -site device.  
Category  3:  Remote configuration capability access may 
be unlimited or controlled through a software switch 
(e.g., password) . 
 The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  
 An event logger is required in the device; it must 
include an event counter (000 to 999), the parameter 
ID, the date and time of the change, and the new value  
of the parameter.  A printed copy of the information 
must be available through the device or through 
another on- site device.  The event logger shall have a 
capacity to retain records equal to 10 times the number of sealable parameters in the device, but not more than 
1000 records are required.  ( Note:   Does not require 
1000 changes to be stored for each parameter.)  
[Nonretroactive as of January  1, 1995]  
(Table Added 2006)  
 S.2.3.  Directional Flow Valves.  – A measuring system shall be equipped with a valve or other effective 
means, automatic in operation and installed in or adjacent to the measuring element, to prevent reversal of flow of the product being measured.  
(Amended 1982)  
 
S.2.4.  Maintenance of Li quid State.  – A device shall be so designed and installed that the product 
being measured will remain in a liquid state during the passage through the meter.  
 
S.2.5.  Thermometer Well.  – For test purposes, means shall be provided to determine the temperatur e of 
the liquid either:  
 
(a) in the liquid chamber of the meter; or  
 (b) in the meter inlet or discharge line and immediately adjacent to the meter.  
(Amended 1987)  
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 S.2.6.  Automatic Temperature Compensation.  – A device may be equipped with an adjustable 
automatic means for adjusting the indication and registration of the measured volume of product to the volume 
at 15  °C (60  °F). 
 
S.2.6.1.  Provision for Deactivating.  – On a device equipped with an automatic temperature-
compensating mechanism that will indicate or record only in terms of liters or gallons adjusted to 15  °C 
(60 °F), provision shall be made to facilitate the deactivation of the automatic temperature- comp ensating 
mechanism so that the meter may indicate, and record if it is equipped to record, in terms of the 
uncompensated volume.  
(Amended 1972)  
 
S.2.6.2.  Provision for Sealing.  – Provision shall be made for applying security seals in such a manner 
that an automatic temperature -compensating system cannot be disconnected and that no adjustment may be 
made to the system.  
 
S.3. Design of Discharge Lines and Discharge Line Valves.  
 
S.3.1.  Diversion of Measured Liquid.  – No means shall be provided by which any me asured liquid can 
be diverted from the measuring chamber of the meter or the discharge line therefrom.  However, two or more 
delivery outlets may be permanently installed if means are provided to insure that:  
 
(a) liquid can flow from only one such outlet at one time; and  
 
(b) the direction of flow for which the mechanism may be set at any time is definitely and conspicuously indicated.  
 
In addition, a manually controlled outlet that may be opened for the purpose of emptying a portion of the system 
to allow  for repair and maintenance operations shall be permitted.  Effective means shall be provided to prevent 
the passage of liquid through any such outlet during normal operation of the device and to indicate clearly and 
unmistakably when the valve controls ar e so set as to permit passage of liquid through such outlet.  
(Amended 1975)  
 
S.3.2.  Delivery Hose.  – The delivery hose of a retail device shall be of the wet -hose type with a shutoff 
valve at its outlet end.  
 
S.4. Marking Requirements.  
 
S.4.1.  Limitation of Use.  – If a device is intended to measure accurately only products having particular 
properties, or to measure accurately only under specific installation or operating conditions, or to measure 
accurately only when used in conjunction with specific accessory equipment, these limitations shall be clearly and permanently stated on the device.  
 S.4.2.  Discharge Rates.  – A device shall be marked to show its designed maximum and minimum 
discharge rates.  The marked minimum discharge rate shall not exceed:  
 
(a) 20 L (5 gal) per minute for stationary retail devices; or  
 (b) 20 % of the marked maximum discharge rate for other retail devices and for wholesale devices.  
(Amended 1987)  
 
Note :  Also see example in Section 3.30. Liquid- Measuring Devices Code, paragraph S.4.4.1. Discharge Rates.  
(Added 2003)  
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 S.4.3.  Location of Marking Information; Retail Motor -Fuel Dispensers.  – The marking information 
required in General Code, paragraph G-S.1. Identification shall appear as follows:  
 
(d) within 60  cm (24  in) to 150 cm (60 in) from the base of the dispenser;  
 
(e) either internally and/or externally provided the information is permanent and easily read; and  
 
(f) on a portion of the device that cannot be readily removed or interchanged (i.e.,  not on a service access 
panel).  
 
Note:   The use of a dispenser key or tool to access internal marking information is permitted for retail motor -fuel dispensers.  
[Nonretroactive as of January  1, 2003]  
(Added 2006)  
 
S.4.4.  Temperature Compensation.  – If a device is equipped with an automatic temperature 
compensator, the primary indicating elements, recording elements, and recorded representation shall be clearly and conspicuously marked to show that the volume delivered has been adjusted to the volu me at 15  °C (60  °F). 
 
N. Notes  
 
N.1. Test Liquid.  – A device shall be tested with the liquid to be commercially measured or with a liquid of the 
same general physical characteristics.  
 
N.2. Vaporization and Volume Change.  – Care shall be exercised to reduce to a minimum, vaporization and 
volume changes.  
 
N.3. Test Drafts.  – Test drafts should be equal to at least the amount delivered by the device in one minute at its 
normal discharge rate.  
(Amended 1982)  
 
N.4. Testing Procedures.  
 
N.4.1.  Normal Tests.  – The “normal” test of a device shall be made at the maximum discharge flow rate 
developed under the conditions of the installation.  Any additional tests conducted at flow rates down to and 
including one -half the sum of the maximum discharge flow rate an d the rated minimum discharge flow rate 
shall be considered normal tests.  
(Amended 1998)  
 
N.4.1.1.  Automatic Temperature Compensation.  – On devices equipped with automatic 
temperature -compensating systems, normal tests shall be conducted as follows:  
 
(a) by comparing the compensated volume indicated or recorded to the actual delivered volume 
adjusted to 15  °C (60  °F); and  
 
(b) with the temperature -compensating system deactivated, comparing the uncompensated volume 
indicated or recorded to the actual delivered volume.  
 
The first test shall be performed with the automatic temperature -compensating system operating in the “as 
found” condition.  On devices that indicate or record both the compensated and uncompensated volume for 
each delivery, the tests in  (a) and (b) may be performed as a single test.  
(Amended 1987)  
 
N.4.1.2.  Repeatability Tests. –  Tests for repeatability should include a minimum of three consecutive 
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 factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2001)  
 
N.4.2.  Special Tests.  – “Special” tests shall be made to develop the operating characteristics of  a device 
and any special elements and accessories attached to or associated with the device.  Any test except as set forth in N.4.1. Normal Tests shall be considered a special test.  
 
N.4.2.1.  For Motor -Fuel Devices.  – A motor -fuel device shall be so tested at a minimum discharge rate 
of: 
 
(a) 20 L (5 gal) per minute; or  
 
(b) the minimum discharge rate marked on the device, whichever is less.  
 
N.4.2.2.  For Other Retail Devices.  – A retail device other than a motor -fuel device shall be tested at a 
minimum discharge rate of the:  
 
(a) minimum discharge rate that can be developed under the conditions of installation; or  
 
(b) minimum discharge rate marked on the device, whichever is greater.  
(Amended 1973)  
 
N.4.2.3.  For Wholesale Devices.  – A wholesale device shall be so tested at a minimum discharge rate 
of: 
 
(a) 40 L (10  gal) per minute for a device with a rated maximum discharge less than 180  L (50  gal) per 
minute.  
 
(b) 20 % of the  marked maximum discharge rate for a device with a rated maximum discharge of 
180 L (50  gal) per minute or more, or  
 
(c) the minimum discharge rate marked on the device, whichever is least.  
(Amended 1987)  
 
N.4.3.  Money -Value Computation Tests.  
 
N.4.3.1.  Laboratory Design Evaluation Tests.  – In the conduct of laboratory design evaluation tests, 
compliance with paragraph  S.1.5.2. Money -Value Computations shall be determined by using the cone gear 
as a reference for the total quantity delivered.  The indicat ed delivered quantity shall agree with the cone 
gear representation with the index of the indicator within the width of the graduation.  The maximum 
allowable variation of the indicated sales price shall be as shown in Table 1. Money -Value Divisions and 
Maximum Allowable Variations for Money -Value Computations on Mechanical Analog Computers.  
 N.4.3.2.  Field Tests.  – In the conduct of field tests to determine compliance with 
paragraph  S.1.5.2. Money -Value Computations the maximum allowable variation in the indicated sales 
price shall be as shown in Table 1. Money -Value Divisions and Maximum Allowable Variations for 
Money- Value Computations on Mechanical Analog Computers.  
(Added 1984)  
 N.5. Temperature Correction.  – Adjustments shall be made for any changes in volume resulting from the 
differences in liquid temperatures between time of passage through the meter and ti me of volumetric determination 
in the prover.  When adjustments are necessary, appropriate petroleum measurement tables should be used.  
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 T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Underregistration and to Overregistration.  – The tolerances hereinafter prescribed shall be 
applied to errors of underregistration and errors of overregistration, whether or not a device is equipped with an 
automatic temperature compensator.  
 T.2. Tolerance Values.  – The maintenance and acceptance tolerances for normal and special tests shall be as 
shown in Table  T.2. Accuracy Classes and Tolerances for LPG and Anhydrous Ammonia Liquid -Measuring 
Devices.  
(Amended 2003)  
 
Table T.2.  
Accuracy Classes and Tolerances for LPG and Anhydrous Ammonia Liquid -Measuring Devices  
Accuracy 
Class  Application  Acceptance 
Tolerance  Maintenance 
Tolerance  Special Test 
Tolerance  
1.0 Anhydrous ammonia, LPG  
(including vehicle -mounted meters)  0.6 % 1.0 % 1.0 % 
(Added 2003)  
 
T.3. Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within applicable tolerance.  This tolerance does not apply to the test of the 
automatic temperature- compensating system.  (Also see N.4.1.2. Repeatability Tests).  
(Added 1992) (Amended 1997 and 2001)  
 
T.4. Automatic Temperature- Compensating Systems.  – The differe nce between the meter error (expressed as a 
percentage) for results determined with and without the automatic temperature -compensating system activated shall 
not exceed:  
 
(a) 1.0 % for mechanical automatic temperature -compensating systems; and  
 
(b) 0.5 % for electronic automatic temperature -compensating systems.  
 
The delivered quantities for each test shall be approximately the same size.  The results of each test shall be within 
the applicable acceptance or maintenance tolerance.  
(Added 1991) (Amended 1992, 1996, and 1997)  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Discharge Rate.  – A device shall be so installed that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  If necessary, means for flow regulation shall be incorporated in the 
installation, in which case this shall be fully effective and automatic in operation.  
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 UR.1.2.  Length of Discharge Hose.  – The length of the discharge hose on a stationary motor -fuel device 
shall not exceed 5.5  m (18  ft), measured from the outside of the housing of the device to the inlet end of the 
discharge nozzle, unless it can be demonstrated that a longer hose is essential to permit deliveries to be made to 
receiving vehicles or vessels.  Unnecessarily remote location of a device shall not be accepted as justification 
for an abnormally long hose.  
(Amended 1991)  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Return of Indication and Recording Elements to Zero.  – The primary indicating elements 
(visual), and the primary recording elements when these are returnable to zero, shall be returned to zero before 
each delivery.  
 UR.2.2.  Condition of Fill of Discharge Hose.  – The discharge hose shall be completely filled  with liquid 
before the “zero” condition is established prior to the start of a commercial delivery, whether this condition is 
established by resetting the primary indicating elements to zero indication or by recording the indications of the 
primary indica ting elements.  (Also see UR.2.1. Return of Indication and Recording Elements to Zero.)  
 UR.2.3.  Vapor -Return Line.  – During any metered delivery of liquefied petroleum gas from a supplier’s 
tank to a receiving container, there shall be no vapor -return lin e from the receiving container to the supplier’s 
tank:  
 
(a) in the case of any receiving container to which normal deliveries can be made without the use of such 
vapor -return line; or  
 
(b) in the case of any new receiving container when the ambient temperature is below 90  °F. 
 
UR.2.4.  Temperature Compensation.  
 
UR.2.4.1.  Use of Automatic Temperature Compensators.  – If a device is equipped with an 
automatic temperature compensator, this shall be connected, operable, and in use at all times.  Such 
automatic temperature compensator may not be removed, nor may a compensated device be replaced with 
an uncompensated device, without the written approval of the weights and measures authority having jurisdiction over the device.  
 
UR.2.4.2.  Temperature Compensa ted Sale.  – All sales of liquefied petroleum gas in a liquid state, 
when the quantity is determined by an approved measuring system equipped with a temperature -
compensating mechanism, or by weight and converted to liters or gallons, or by a calibrated container, sh all 
be in terms of liters or the U.S. gallon of 231  in
3 at 15  °C (60  °F). 
(Added 1984)  
 UR.2.4.3.  Invoices.  – Any invoice based on a reading of a device that is equipped with an 
automatic temperature compensator or based on a weight converted to gallons, o r based on the volume of a 
calibrated container, shall have shown thereon that the volume delivered has been adjusted to the volume at 15 °C (60  °F). 
(Amended 1984)  
 UR.2.4.4.  Automated Temperature- Compensating Systems.  – Means for determining the 
temperature of measured liquid in an automatic temperature -compensating system shall be so designed and 
located that, in any “usual and customary” use of the system, the resulting indications and/or recorded representations are within applicable tolerances.  
(Added 1987)  
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 UR.2.5.  Ticket in Printing Device.  – A ticket shall not be inserted into a device equipped with a ticket 
printer until immediately before a delivery is begun, and in no case shall a ticket be in the device when the 
vehicle is in motion while on a public street, highway, or thoroughfare.  
 
UR.2.6.  Ticket Printer; Customer Ticket.  – Vehicle -mounted metering systems shall be equipped with a 
ticket printer.  The ticket printer shall be used for all sales; a copy of th e ticket issued by the device shall be left 
with the customer at the time of delivery or as otherwise specified by the customer.  
(Added 1992)  
 
 
 
 
 
 
 
 
 
 
  
 
 
 
  
 
 
 
  
  
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
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 Section 3.33.  Hydrocarbon Gas Vapor -Measuring Devices40 
 
 
A. Application  
 
A.1. General.  – This code applies to devices used for the measurement of hydrocarbon gas in the vapor state, such 
as propane, propylene, butanes, butylenes , ethane, methane, natural gas, and any other hydrocarbon gas/air mix.  
(Amended 1984, 1986, 1988, and 1991)  
 A.2. Exceptions.  – This code does not apply to:  
 
(a) Liquid -measuring devices used for dispensing liquefied petroleum gases in liquid form. (Also see  
Section  3.32.  Code for Liquefied Petroleum Gas and Anhydrous Ammonia Liquid -Measuring Devices.)  
 (b) Natural, liquefied petroleum, and manufactured -gas-vapor meters when these are operated  in a public 
utility system.  
 
(c) Mass flow meters. (Also see Section  3.37. Code for Mass Flow Meters.)  
(Added 1994)  
 
A.3. Additional Code Requirements. – In addition to the requirements of this code, Hydrocarbon Gas Vapor -
Measuring Devices shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A device shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  
 
S.1.1.2.  Units.  – A volume -measuring device shall indicate, and record if equipped to record, its 
deliveries in terms of cubic meters or cubic feet, or multiple or decimal subdivisions of cubic meters or cubic feet.  
(Amended 1972 and 1991)  
 
S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated delivery, and recorded 
delivery if the device is equipped to record, shall not exceed:  
 
(a) 1 m
3 (1000 dm3) (100  ft3) when the maximum rated gas capacity is less than 280  m3/h 
(10 000 ft3/h); 
 
(b) 10 m3 (1000 ft3) when the maximum rated gas capacity is 280  m3/h (10  000 ft3/h) up to, but not 
including, 1700 m3/h (60  000 ft3/h); and  
 
                                                           
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 (c) 100 m3 (10 000 ft3) when the maximum rated gas capacity is 1700  m3/h (60  000 ft3/h) or more.  
(Amended 1972, 1988, and 1991)  
 
S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall advance digitally or continuously and be susceptible to advancement only by the mechanical 
operation of the device.  
 
S.1.1.5.  Provin g Indicator.  – Devices rated less than 280  m3/h (10  000 ft3/h) gas capacity shall be 
equipped with a proving indicator measuring 0.025, 0.05, 0.1, 0.2, or 0.25 m3 per revolution, (1, 2, 5, or 
10 ft3 per revolution) for testing the meter.  Devices with larg er capacities shall be equipped as follows:  
 
(a) Devices rated 280  m3 (10 000 ft3) up to but not including 1700 m3/h (60 000 ft3/h) gas capacity 
shall be equipped with a proving indicator measuring not greater than 1  m3 (100 ft3) per 
revolution.  
 
(b) Devices rated 1700  m3/h (60  000 ft3/h) gas capacity or more shall be equipped with a proving 
indicator measuring not more than 10  m3 (1000 ft3) per revolution.  
 
The test circle of the proving indicator shall be divided into ten equal parts.  Additional sub divisions of 
one or more of such equal parts may be made.  
(Amended 1973 and 1988)  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 
S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and in no case should it exceed 1.0  mm 
(0.04  in) for indicating elements and 0.5  mm (0.02  in) for provi ng circles.  
 
S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall be not less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the indicator is continuous, at the point of widest separation of the graduations.  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 
S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used.  
 S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than the:  
 
(a) width  of the narrowest graduation; * and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 (b) width  of the minimum clear interval between graduations.  
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 When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 
S.1.3.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.1.3.5 . Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
S.2. Design of Measuring Elements.  
 
S.2.1.  Pressure Regulation.  – The vapor should be measured at a normal gauge pressure (psig) of:  
(Amended 1991)  
 
(a) 2740 Pa ±  685 Pa (11  in of  water column (0.40 psig) ± 2.75 in of water column (0.10 psig)) for 
liquefied petroleum gas vapor; or  
 
(b) 1744 Pa ±  436 Pa (7  in of water column (0.25 psig) ± 1.75 in of water column (0.06 psig)) for natural 
and manufactured gas.  
 When vapor  is measured at a pressure other than what is specified above for the specific product, a volume 
multiplier shall be applied within the meter or to the billing invoice based on the following equation:  
 
AAP + GP  
VPM  =  
AAP + NGP  
 
Where:  
VPM  = Volume pressure multiplier  
AAP  = Assumed atmospheric pressure in Pa or psia  
GP = Gauge pressure in Pa or psig  
NGP  = Normal gauge pressure in Pa or psig  
 
The assumed atmospheric pressure is to be taken from Tables  2 and  2M. 
 
When liquefied petroleum gas vapor is measured at a pressu re of 6900  Pa (1  psig) or more, the delivery pressure 
shall be maintained within ±  1725 Pa (±  0.25 psig). 
 
Pressure variations due to regulator lock off shall not increase the operating pressure by more than 25  %. 
(Amended 1980, 1984, and 1991)  
 
S.2.2.  Provision for Sealing.  – Adequate provision shall be made for applying security seals in such a 
manner that no adjustment or interchange may be made of any measurement element.  
 
S.2.3.  Maintenance of Vapor State.  – A device shall be so designed and installed that the product being 
measured will remain in a vapor state during passage through the meter.  
 S.2.4.  Automatic Temperature Compensation.  – A device may be equipped with an adjustable 
automatic means for adjusting the indication and registration of the measured volume of vapor product to the volume at 15 °C (60  °F). 
 
S.3. Design of Discharge Lines.  
 
S.3.1.  Diversion of Measured Vapor.  – No means shall be provided by which any measured vapor can 
be diverted from the measuring chamber of the meter or the discharge line therefrom.  
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 S.4. Marking Requirements.  
 S.4.1.  Limitations of Use.  – If a device is intended to measure accurately only products having 
particular properties, or to measure accurately only under specific installation or operating conditions, or to 
measure accurately only when used in conjunction with specific accessory equipment, these limitations shall be 
clearly and perma nently stated on the device.  
 
S.4.2.  Discharge Rates.  – A device shall be marked to show its rated gas capacity in cubic meters per 
hour or cubic feet per hour.  
 
S.4.3.  Temperature Compensation.  – If a device is equipped with an automatic temperature 
compe nsator, this shall be indicated on the badge or immediately adjacent to the badge of the device and on the 
register.  
 S.4.4.  Badge.  – A badge affixed in a prominent position on the front of the device shall show the 
manufacturer’s name, serial number and m odel number of the device, and capacity rate of the device for the 
particular products that it was designed to meter as recommended by the manufacturer.  
 
N. Notes  
 N.1. Test Medium.  – The device shall be tested with air or the product to be measured.  
(Amended 1991)  
 N.2. Temperature and Volume Change.  – Care should be exercised to reduce to a minimum any volume 
changes.  The temperature of the air, bell -prover oil, and the meters under test should be within 1 °C (2  °F) of one 
another.  The devices shou ld remain in the proving room for at least 16  hours before starting any proving operations 
to allow the device temperature to approximate the temperature of the proving device.  
 
N.3. Test Drafts.  – Except for low -flame tests, test drafts shall be at least equal to one complete revolution of the 
largest  capacity proving indicator, and shall in no case be less than 0.05  m
3 or 2 ft3.  All flow rates shall be 
controlled by suitable outlet orifices.  
(Amended 1973 and 1991)  
 
Table 1.  
Capacity of Low -Flow Test Rate Orifices  w ith Respect to Device Capacity  
Metric Units  U.S. Customary Units  
Rated Capacity  Low -Flow Test Rate  Rated Capacity  Low -Flow Test Rate  
Up to and including 7  m3/h 0.007  m3/h Up to and including 250 ft3/h 0.25 ft3/h 
Over 7  m3/h up to and including 
14 m3/h 0.014  m3/h Over  250 ft3/h up to and 
including 500  ft3/h 0.50 ft3/h 
Over 14  m3/h 0.1 % of capacity rate  Over  500 ft3/h 0.1 % of capacity rate  
 
N.4. Test Procedures.  – If a device is equipped with an automatic temperature compensator, the proving device 
reading shall be corrected to 15  °C (60  °F), using an approved table.  
(Amended 1972)  
 
N.4.1.  Normal Tests.  – The normal test of a device shall be made at a rate not to  exceed the capacity rate 
given on the badge of the meter.  
(Amended 1988)  
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 N.4.1.1.  Automatic Temperature Compensation.  – If a device is equipped with an automatic 
temperature compensator, the quantity of the test draft indication of the standard shall be corrected to 15  °C 
(60 °F). 
 
N.4.1.2.  Repeatability  Tests. – Tests for repeatability  should include a minimum of three consecutive 
test drafts of approximately the same size and be conducted under controlled conditions where variations in factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2002)  
 
N.4.2.  Special Tests.  – “Special” tests shall be made to develop the operating characteristics of a device 
and any special elements and accessories attached to or associated with the device.  Any test except as set forth 
in N.4.1. Normal Tests shall b e considered a special test.  
 
N.4.2.1.  Slow Test.  – The device shall be tested at a rate not less than 20  % of the marked capacity rate, 
or (at the check rate) not less than the minimum flow rate if marked on the device, whichever is less.  
(Amended 1988)  
 
N.4.2.2.  Low -Flame Test.  – The device shall be tested at an extremely low -flow rate as given in 
Table  1.  The test shall consist of passing air at a pressure of 375  Pa (1.5  in water column) through the 
meter for not less than 60  minutes.  The meter shall continue to advance at the conclusion of the test period.  
(Amended 1990 and 1991)  
 
N.4.2.3.  Pressure Regulation  Test.  – On devices operating at a pressure of 6900 Pa (1  psig) or more, a 
pressure regulation test shall be made at both the minimum and maximum use load to determine the proper 
operation of the regulator and the proper sizing of the piping and dispensing equipment.  These tests may 
include a test of 24  hours during which the pressure is recorded.  
(Added 1984)  
 
N.5. Temperature Correction.  – Correc tions shall be made for any changes in volume resulting from the 
difference in air temperatures between time of passage through the device and time  of volumetric  determination in 
the proving  device.  
 N.6. Frequency of Test.  – A hydrocarbon gas vapor -measur ing device shall be tested before installation and 
allowed to remain in service for 10  years from the time last tested without being retested, unless a test is requested 
by: 
 
(a) the purchaser of the product being metered;  
 (b) the seller of the product being metered; or  
 
(c) the weights and measures official.  
 
T. Tolerances  
 
T.1. Tolerance Values on Normal Tests and on Special Tests Other Than Low -Flame Tests.  – Maintenance 
and acceptance tolerances for normal and special tests for hydrocarbon gas vapor -measuring devices shall be as 
shown in Table  T.1. Accuracy Classes and Tolerances for Hydrocarbon Gas Vapor -Measuring Devices.  
(Amended 1981 and 2003)  
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 Table T.1.  
Accuracy Classes and Tolerances for Hydrocarbon Gas Vapor -Measuring Devices  
Accuracy Class  Application  Acceptance 
Tolerance Maintenance 
Tolerance 
3.0 Gases at low pressure 
(for example, LPG vapor)  Overregistration  1.5 % 1.5 % 
Underregistration  3.0 % 3.0 % 
(Added 2003)  
 T.2. Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 0.9  % and the results of each test shall be within the 
applicable tolerance.  ( Also see N.4.1.2. Repea tability Test.)  
(Added 2002)  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Capacity Rate.  – A device shall be so installed that the actual maximum flow rate will not exceed 
the capacity rate except for short durations.  If necessary, means for flow regulation shall be incorporated in the 
installation, in which case this shall be fully effectiv e and automatic in operation.  
 
UR.1.2.  Leakage.  – The metering system shall be installed and maintained as a pressure- tight and leak -free 
system.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Automatic Temperature Compensation.  – A compensated device may not be replac ed with an 
uncompensated device without the written approval of the weights and measures authority having jurisdiction 
over the device.  
 
UR.2.2.  Invoices.  – A customer purchasing hydrocarbon gas measured by a vapor meter shall receive from 
the seller an in voice for each billing period.  The invoice shall clearly and separately show the following:  
 
(a) The opening and closing meter readings and the dates of those readings.  
 
(b) The altitude correction factor.  
 (c) The total cubic meters (cubic feet) billed, corrected for elevation.  
 (d) The charge per cubic meter (cubic foot) after correction for elevation.  
 
(e) All periodic charges independent of the measured gas, such as meter charges, meter reading fees, 
service charges or a minimum charge for a minimum nu mber of cubic meters (cubic feet).  
 
(f) The total charge for the billing period.  
 
If the vapor meter is equipped with an automatic temperature compensator, or any other means are used to 
compensate for temperature, the invoice shall show that the volume has been adjusted to the volume at 15  °C 
(60 °F). 
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UR.2.3.  Correction for Elevation.  – The metered volume of gas shall be corrected for changes in the 
atmospheric pressure with respect to elevation to the standard pressure of 101.56 kPa (14.73 psia).  The 
appropriate altitude correction factor from Table 2M. Corrections for Altitude, Metric Units 
or Table  2. Corrections for Altitude, U.S. Customary Units shall be used.  (The table is modified from NIST 
Handbook  117.)  
(Amended 1 988) 
 
Elevation correction factors (ACF) were obtained by using the following equation:  
 
GP of gas + AAP  
ACF  =  
base pressure  
 
Where:  
GP = gauge pressure  
AAP  = assumed atmospheric pressure  
base pressure  = 101.560 kPa = 14.73 psia 
 
2740 Pa  = 11 in of water column = 0.397 psig  
 
1744 Pa  = 7 in of water column = 0.253 psig 
(Added 1988)  
 UR.2.4. Valves and Test Tee.  – All gas meter installations shall be provided with a shut -off valve located 
adjacent to and on the inlet side of the meter.  In the  case of a single meter installation utilizing a liquefied 
petroleum gas tank, the tank service valve may be used in lieu of the shut -off valve.  All gas meter installations 
shall be provided with a test tee located adjacent to and on the outlet side of the meter.  
[Nonretroactive  as of January  1, 1990]  
(Added 1989)  
 
UR.2.5.  Use of Auxiliary Heated Vaporizer Systems.  – Automatic temperature compensation shall be used 
on hydrocarbon gas vapor meters equipped with an auxiliary heated vaporizer system unless there is sufficient 
length of underground piping to provide gas at a uniform temperature to the meter inlet.  When required by 
weights and measures officials, a thermometer well (appropriately protected against freezing) shall be installed immediately up -stream of the meter.  
(Added 1990)  
 3.33.  Hydrocarbon Gas Vapor -Measuring Devices   Handbook 44 –  20152016  
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 Table 2M.  
Corrections for Altitude, Metric Units  
Elevation  
(meters)  Altitude  
Correction  
Factor  Assumed  
Atmospheric  
Pressure  Assumed Atmospheric  
Pressure Plus  
Gauge Pressure  
2.74 kPa 
Gauge  
Pressure  1.74 kPa 
Gauge  
Pressure  (kPa) 2.74 kPa 
Gauge  
Pressure  1.74 kPa 
Gauge  
Pressure  
 
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  − 50  to  
120  to  
300  to  
470  to  
650  to  
830  to  
1020  to  
1210  to  
1400  to  
1590  to  
1790  to  
2000  to  
2210  to  
2420  to  
2640  to  
2860  to  
3080  to  
3320  to  
3560  to  
3800  to  
4050  to  
4310  to  120 
300 
470 
650 
830 
1020  
1210  
1400  
1590  
1790  
2000  
2210  
2420  
2640  
2860  
3080  
3320  
3560  
3800  
4050  
4310  
4580  1.02 
1.00 
0.98 
0.96 
0.94 
0.92 
0.90 
0.88 
0.86 
0.84 
0.82 
0.80 
0.78 
0.76 
0.74 
0.72 
0.70 
0.68 
0.66 
0.64 
0.62 
0.60 1.01 
0.99 
0.97 
0.95 
0.93 
0.91 
0.89 
0.87 
0.85 
0.83 
0.81 
0.79 
0.77 
0.75 
0.73 
0.71 
0.69 
0.67 
0.65 
0.63 
0.61 
0.59 100.85  
98.82  
96.79  
94.76  
92.73  
90.70  
88.66  
86.63  
84.60  
82.57  
80.54  
78.51  
76.48  
74.45  
72.41  
70.38  
68.35  
66.32  
64.29  
62.26  
60.23  
58.20  103.59  
101.56  
99.53  
97.50  
95.47  
93.44  
91.40  
89.37  
87.34  
85.31  
83.28  
81.25  
79.22  
77.19  
75.15  
73.12  
71.09  
69.06  
67.03  
65.00  
62.97  
60.94  102.58  
100.54  
98.51  
96.48  
94.45  
92.42  
90.39  
88.36  
86.33  
84.29  
82.26  
80.23  
78.20  
76.17  
74.15  
72.12  
70.08  
68.05  
66.01  
63.98  
61.95  
59.92  
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 Table 2.  
Corrections for Altitude, U.S. Customary Units  
Elevation  
(feet)  Altitude  
Correction  
Factor  Assumed  
Atmospheric  
Pressure  Assumed Atmospheric 
Pressure Plus Gauge 
Pressure  
11 inch 
WC 7 inch 
WC (psia)  11 inch WC  
(psia)  7 inch WC  
(psia)  
 
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  
above  − 150  to  
400  to  
950  to  
1 550  to  
2 100  to  
2 700  to  
3 300  to  
3 950  to  
4 550  to  
5 200  to  
5 850  to  
6 500  to  
7 200  to  
7 900  to  
8 600  to  
9 350  to  
10 100  to  
10 850  to  
11 650  to  
12 450  to  
13 250  to  
14 100  to  400 
950 
1 550  
2 100  
2 700  
3 300  
3 950  
4 550  
5 200  
5 850  
6 500  
7 200  
7 900  
8 600  
9 350  
10 100  
10 850  
11 650  
12 450  
13 250  
14 100  
14 950  1.02 
1.00 
0.98 
0.96 
0.94 
0.92 
0.90 
0.88 
0.86 
0.84 
0.82 
0.80 
0.78 
0.76 
0.74 
0.72 
0.70 
0.68 
0.66 
0.64 
0.62 
0.60 1.01 
0.99 
0.97 
0.95 
0.93 
0.91 
0.89 
0.87 
0.85 
0.83 
0.81 
0.79 
0.77 
0.75 
0.73 
0.71 
0.69 
0.67 
0.65 
0.63 
0.61 
0.59 14.64  
14.35  
14.05  
13.76  
13.46  
13.17  
12.87  
12.58  
12.28  
11.99  
11.69  
11.40  
11.10  
10.81  
10.51  
10.22  
9.92 
9.63 
9.33 
9.04 
8.75 
8.45 15.04  
14.74  
14.45  
14.15  
13.86  
13.56  
13.27  
12.97  
12.68  
12.38  
12.09  
11.79  
11.50  
11.20  
10.91  
10.61  
10.32  
10.03  
9.73 
9.44 
9.14 
8.85 14.89  
14.60  
14.30  
14.01  
13.71  
13.42  
13.12  
12.83  
12.53  
12.24  
11.94  
11.65  
11.35  
11.06  
10.76  
10.47  
10.17  
9.88 
9.58 
9.29 
9.00 
8.70 
 
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 Section 3.34.  Cryogenic Liquid -Measuring Devices  
 
 
A. Application  
 
A.1. General.  – This code applies to devices used for the measurement of cryogenic liquids such as, but not 
limited to oxygen, nitrogen, hydrogen, and argon.  
(Amended 1986 and 1995)  
 A.2. Exceptions.  – This code does not apply to the following:  
 
(a) Devices used for dispensing liquefied petroleum gases (for which see Section  3.32. Code for Liquefied 
Petroleum Gas and Anhydrous Ammonia Liquid- Measuring Devices).  
 (b) Devices used solely for dispensing a product in connection with operations in which the amount dispensed does not affect customer charges.  
 
(c) Devices used solely for dispensing liquefied natural g as. 
 (d) Mass flow meters.  (Also see Section  3.37. Code for Mass Flow Meters.)  
(Added 1994)  
 A.3. Additional Code Requirements.  – In addition to the requirements of this code, Cryogenic Liquid - 
Measuring Devices shall meet the requirements of Section 1.10 . General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A device shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  
 
S.1.1.2.  Units.  – A device shall indicate and record, if equipped to record, its deliveries in terms of:  
kilograms or pounds; liter s or gallons of liquid at the normal boiling point of the specific cryogenic 
product; cubic meters (cubic feet) of gas at a normal temperature of 21  °C (70  °F) and an absolute pressure 
of 101.325 kPa (14.696 psia); or decimal subdivisions or multiples of the measured units cited above.  
(Amended 2002)  
 S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated delivery, and recorded 
delivery, if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) for small delivery devices:  
 
(1) 1 L; 
 
(2) 0.1 gal; 
 
(3) 1 kg; 
 (4) 1 lb; 
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 (5) 0.1 m3 of gas; or  
 
(6) 10 ft3 of gas.  
 
(b) for large delivery devices:  
 
(1) 10 L; 
 (2) 1 gal; 
 
(3) 10 kg; 
 
(4) 10 lb; 
 
(5) 1 m
3 of gas; or  
 
(6) 100 ft3 of gas.  
(Amended 2002)  
 
S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only by the normal operation of the device.  However, a device may be cleared by advancing its elements to zero, but only if: 
 
(a) the advancing movement, once started, cannot be stopped until zero is reached; or  
 
(b) in the case of indicating elements only, such elements are automatically obscured until the 
elements reach the correct zero position.  
 
S.1.1.5.  Return to Zero.  – Primary indicating and recording elements shall be readily returnable to a 
definite zero indication.  Means shall be provided to prevent the return of primary indicating elements and 
of primary recording elements beyond their correct zero position.  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 
S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the width of main graduations shall be 
not more than 50  % greater than the width of subordinate gra duations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall be no less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the indicator is continuous, at the point of widest separation of the graduations.  
(Also see S.1.3.6. Travel of Indicator.)  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
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 S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than the:  
 
(a) width of the narrowest graduation;* and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 
(b) width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduatio n shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 
S.1.3.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.1.3.5.  Paralla x. – Parallax effect shall be reduced to the practicable minimum.  
 
S.1.3.6.  Travel of Indicator.  – If the most sensitive element of the primary indicating element uses an 
indicator and graduations, the relative movement of these parts corresponding to the smallest indicated 
value shall be not less than 0.5  mm (0.20 in). 
 
S.1.4.  Computing -Type Device.  
 
S.1.4.1.  Printed Ticket.  – Any printed ticket issued by a device of the computing type on which there is 
printed the total computed price shall have printed clearly thereon also the total quantity of the delivery and 
the price per unit.  
 S.1.4.2.  Money -Value Computations.  – Money- value computations shall be of the full- computing type 
in which the money- value at a single unit price, or at each of a series of unit prices, shall be computed for 
every delivery within either the range of measurement of the device or the range of the co mputing 
elements, whichever is less.  Value graduations shall be supplied and shall be accurately positioned.  The 
total price shall be computed on the basis of the quantity indicated when the value of the smallest division 
indicated is equal to or less th an the values specified in S.1.1.3. Value of Smallest Unit.  
 
S.1.4.3.  Money -Values, Mathematical Agreement.  – Any digital money -value indication and any 
recorded money -value on a computing type device shall be in mathematical agreement with its associated 
quantity indication or representation to within 1  cent of money -value.  
 
S.2. Design of Measuring Elements.  
 
S.2.1.  Vapor Elimination.  – A measuring system shall be equipped with an effective vapor eliminator 
or other effective means to prevent the measurem ent of vapor that will cause errors in excess of the applicable 
tolerances.  (Also see Section  T. Tolerances.)  
 
S.2.2.  Directional Flow Valves.  – A valve or valves or other effective means, automatic in operation, to 
prevent the reversal of flow shall be i nstalled in or adjacent to the measuring device.  
(Amended 1978)  
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 S.2.3.  Maintenance of Liquid State.  – A device shall be so designed that the product being measured 
will remain in a liquid state during passage through the device.  
 
S.2.4.  Automatic Temperature or Density Compensation.  – A device shall be equipped with 
automatic means for adjusting the indication and/or recorded representation of the measured quantity of the 
product, to indicate and/or record in terms of:  kilograms or pounds; or lite rs or gallons of liquid at the normal 
boiling point of the specific cryogenic product; or the equivalent cubic meters (cubic feet) of gas at a normal 
temperature of 21  C (70  F) and an absolute pressure of 101.325  kPa (14.696  lb/in2 absolute).  When a 
compensator system malfunctions , the indicating and recording elements may indicate and record in 
uncompensated volume if the mode of operation is clearly indicated, e.g., by a marked annunciator, recorded 
statement, or other obvious means .* 
[*Nonre troactive as of January  1, 1992]  
(Amended 1991 and 2002)  
 S.2.5.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before an adjustment or interchange may be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries;  
 
(c) any automatic temperature or density compensating system; and  
 
(d) any metrological parameter that will affect the metrological integrity of the device or system.  
 When applicable, any adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 
[Audit trails shall use the format set forth in Table  S.2.5. Categories of Device and Methods of Sealing ]* 
[*Nonretroactive as of January  1, 1995]  
(Amended 2006)  
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 Table S.2.5.  
Categories of Device and Methods of Sealing 
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for  configuration 
parameters.  
Category  2:  Remote configuration capability, but access 
is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  The hardware enabling access for remote 
communication must be on- site.  The hardware must 
be sealed using a physical seal or an event counter 
for calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or  
at the system controller; however, an adequate 
number of counters must be provided to monitor the 
calibration and configuration parameters of the 
individual devices at a location.  If the counters are 
located in the system controller rather than at the 
individual device, means must be provided to 
generate a hard copy of the information through an 
on-site device.  
Category  3:  Remote configuration capability access may 
be unlimited or controlled through a software switch 
(e.g., password) . 
 The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  
 An event logger is required in the device; it must 
include an event counter (000 to 999), the  parameter 
ID, the date and time of the change, and the new 
value of the parameter.  A printed copy of the 
information must be available through the device or 
through another on -site device.  The event logger 
shall have a capacity to retain records equal t o 10 
times the number of sealable  parameters in the 
device, but not more than 1000 records are required.  
(Note:   Does not require 1000 changes to be stored 
for each parameter.)  
[Nonretroactive  as of January  1, 1995 ] 
(Table Added 2006)  
 
S.3. Design of Discharge Lines and Discharge Line Valves.  
 
S.3.1.  Diversion of Measured Liquid.  – No means shall be provided by which any measured liquid can 
be diverted from the measuring chamber of the device or the discharge line therefrom, except that a manually 
controlled outlet that may be opened for purging or draining the measuring system shall be permitted.  Effective 
means shall be provided to prevent the passage of liquid through any such outlet during normal operation of the device and to indicate clearly and unmistakably when the valve controls are so set as to permit passage of liquid 
through such outlet.  
 
S.3.2.  Discharge Hose.  – The discharge hose of a measuring system shall be of the completely draining 
dry-hose type.  
 
S.4. Marking Requirements.  
 
S.4.1.  Limitation of Use.  – If a measuring system is intended to measure accurately only liquids having 
particular properties, or to measure accurately only under specific installation or operating conditions, or to 3.34. Cryogenic Liquid- Measuring Devices   Handbook 44 –  20152016  
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 measure accurately only when used in conjunction with specific accessory equipment, these limitations shall be 
clearly and permanently marked on the device.  
 
S.4.2.  Discharge Rates.  – A meter shall be marked to show its designed maximum and minimum 
discharge rates.  
 
S.4.3.  Temperature or Density Compensa tion.  – Devices equipped with an automatic temperature or 
density compensator, shall be clearly and conspicuously marked on the primary indicating elements, recording elements, and recorded representations to show that the quantity delivered has been adjus ted to the conditions 
specified in S.2.4. Automatic Temperature or Density Compensation.  
 
N. Notes  
 
N.1. Test Liquid.  – A meter shall be tested with the liquid to be commercially measured except that, in a type 
evaluation examination, nitrogen may be used.  
 N.2. Vaporization and Volume Change.  – Care shall be exercised to reduce to a minimum vaporization and 
volume changes.  When testing by weight, the weigh tank and transfer systems shall be pre -cooled to liquid 
temperature prior to the start of the test to avoid the venting of vapor from the vessel being weighed.  
 
N.3. Test Drafts.  
 
N.3.1.  Gravimetric Test.  – Weight test drafts shall be equal to at least the amount delivered by the 
device in 2  minutes at its maximum discharge rate, and shall in no case be less than 907  kg (2000  lb). 
 
N.3.2.  Transfer Standard Test.  – When comparing a meter with a calibrated transfer standard, the test 
draft shall be equal to at least the amount delivered by the device in two  minutes at its maximum discharge rate, 
and shall i n no case be less than 180  L (50  gal) or equivalent thereof.  When testing uncompensated volumetric 
meters in a continuous recycle mode, appropriate corrections shall be applied if product conditions are 
abnormally affected by this test mode.  
(Amended 1976)  
 N.4. Density.  – Temperature and pressure of the metered test liquid shall be measured during the test for the 
determination of density or volume correction factors when applicable.  For Liquid Density and Volume Correction 
Factors (with respect to temperature and press ure) the publications shown in Table  N.4. Density or Volume 
Correction Factors shall apply.  
(Amended 1986 and 2004)  Handbook 44 –  20152016    3.34.  Cryogenic Liquid- Measuring Devices  
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 Table N.4.  
Density or Volume Correction Factors  
Cryogenic Liquid  Publication  
Argon  Tegeler , Ch., Span, R., Wagner, W.  “A New Equation of  State for Argon Covering 
the Fluid Region for Temperatures from the Melting Line to 700 K at Pressures up to 
1000 Mpa.”   J. Phys. Chem. Ref. Data , 28(3):779-850, 1999.  
Ethylene  Smukala , J., Span, R., Wagner, W.  “New Equation of State for Ethylene Covering the 
Fluid Region for Temperatures from the Melting Line to 450  k at Pressures up to 
300 Mpa.”  J. Phys. Chem. Ref. Data , 29(5):1053- 1122, 2000.  
Nitrogen  Span, R., Lemmon, E.W., Jaco bsen, R.T, Wagner, W., and Yokozeki, A.  “A 
Reference Thermodynamic Property Formulation for Nitrogen.”  J. Phys. Chem. Ref. 
Data , Volume  29, Number  6, pp.  1361- 1433, 2000.  
Oxygen  Schmidt, R., Wagner, W.  “A New Form of the Equation of State for Pure Subs tances 
and its Application to Oxygen.”  Fluid Phase Equilib. , 19:175- 200, 1985  
Hydrogen Leachman, J.  W., Jacobsen, R.  T., Lemmon, E.W., and Penoncello, S.G. 
“Fundamental Equations of State for Parahydrogen, Normal Hydrogen, and 
Orthohydrogen”  J. Phys. Ch em. Ref. Data , Volume 38, Number 3, pp. 565, 2009.  
Note:   A complete database program containing all of the most recent equations for calculating density for various 
cryogenic liquids is available at www. nist.gov/srd/nist23.cfm .  There is a fee for  download of this database.  
(Added 2004)  
 
N.5. Testing Procedures.  
 
N.5.1.  Normal Tests.  – The “normal” tests of a device shall be made over a range of discharge rates that 
may be anticipated under the conditions of installation.  
 
N.5.1.1.  Repeatability  Tests. – Tests for repeatability  should include a minimum of three consecutive 
test drafts  of approximately the same size and be conducted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2001)  
 
N.5.2.  Special Tests.  – Any test except as set forth in N.5.1. Normal Tests shall be considered a “special” 
test.  Tests shall be conducted, if possible, to evaluate any special elements or accessories attached to or 
associated with the device.  A device shall be tested at a minimum discharge rate of:  
 
(a) 50 % of the maximum discharge rate developed under the conditions of installation, or the minimum 
discharge rate marked on the device, whichever is less; or  
 
(b) the lowest discharge rate practicable under conditions of  installation.  
 Special tests may be conducted to develop any characteristics of the device that are not normally anticipated 
under the conditions of installation.  
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 N.6. Temperature Correction.  – Corrections shall be made for any changes in volume resulting from the 
differences in liquid temperature between time of passage through the meter and time of volumetric  determination of 
test draft.  
 
N.7. Automatic Temperature or Density Compensation.  – When a device is equipped with an automatic 
temperature or density compensator, the compensator shall be tested by comparing the quantity indicated or 
recorded by the device (with the compensator connected and operating) with the actual delivered quantity  corrected 
to the normal boiling point of the cryogenic product being measured or to the normal temperature and pressure as applicable.  
 
T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Underregistration  and to Overregistration.  – The tolerances hereinafter prescribed shall be 
applied to errors of under registration and errors of over registration.  
 
T.2. Tolerance Values.  – The maintenance and acceptance tolerances for normal and special tests shall be as 
shown in Table  T.2. Accu racy Classes and Tolerances for Cryogenic Liquid -Measuring Devices.  
(Amended 2003)  
 
Table T.2.  
Accuracy Classes and Tolerances for Cryogenic Liquid -Measuring Devices  
Accuracy 
Class  Application  Acceptance 
Tolerance Maintenance 
Tolerance Special Test 
Tolerance 
2.5 Cryogenic products; liquefied compressed gases 
other than liquid carbon dioxide  1.5 %  2.5 %  2.5 %  
(Added 2003)  
 
T.3. On Tests Using Transfer Standards.  – To the basic tolerance values that would otherwise be applied, there 
shall be added an amount equal to two times the standard deviation of the applicable transfer standard when 
compared to a basic reference standard.  
(Added 1976)  
 
T.4. Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within the applicable tolerance.  Also see N.5.1.1. Repeatability Tests.  
(Added 2001)  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Discharge Rate.  – A device shall be so installed that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  If necessary, means for flow regulation shall be incorporated in the 
installation.  
 
UR.1.2.  Length of Discharge Hose.  – The discharg e hose shall be of such a length and design as to keep 
vaporization of the liquid to a minimum.  
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 UR.1.3.  Maintenance of Liquid State.  – A device shall be so installed and operated that the product being 
measured shall remain in the liquid state during pass age through the meter.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements (visual) 
and the primary recording elements shall be returned to zero immediately before each delivery.  
 
UR.2.2.  Condition of Discharge System.  – The discharge system, up to the measuring element, shall be 
precooled to liquid temperatures before a “zero” condition is established prior to the start of a commercial 
delivery.  
 
UR.2.3.  Vapor Return Line.  – A vapor return line shall not be used during a metered delivery.  
(Amended 1976)  
 
UR.2.4.  Drainage of Discharge Line.  – On a dry- hose system, upon completion of a delivery, the vendor 
shall leave the discharge line connected to the receiving container with the valve adjacent to the meter in the 
closed position and the valve at the discharge line outlet in the open position for a period of at least:  
 
(a) 1 minute for small delivery devices; and  
 
(b) 3 minutes for large delivery devices  
 
to allow vaporization of some product in the discharge line to force the remainder of the product in the line to flow into the receiving c ontainer.  
(Amended 1976)  
 UR.2.5.  Conversion Factors.  – Established conversion values (Also see references in Table N.4. Density or 
Volume Correction Factors.) shall be used whenever metered liquids are to be billed in terms of:  
 
(a) kilograms or pounds based on a meter indication of liters, gallons, cubic meters of gas, or cubic feet of 
gas;  
 
(b) cubic meters or cubic feet of gas based on a meter indication of liters or gallons, kilograms, or pounds; 
or 
 (c) liters or gallons based o n a meter indication of kilograms or pounds, cubic meters of gas or cubic feet 
of gas.  
 
All sales of cryogenics shall be based on either kilograms or pounds, liters or gallons of liquid at NBP
41, cubic 
meters of gas or cubic feet of gas at NTP1. 
(Amended 1986)  
 
UR.2.6.  Temperature or Density Compensation.  
 
UR.2.6.1.  Use of Automatic Temperature or Density Compensators.  – If a device is equipped 
with an automatic temperature or density compensator, this shall be connected, operable, and in use at all 
times.  Such automatic temperature or density compensator may not be removed, nor may a compensated 
device be replaced wit h an uncompensated device, without the written approval of the weights and 
measures authority having jurisdiction over the device.  
                                                           
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UR.2.6.2.  Tickets or Invoices.  – Any written invoice or printed ticket based on a reading of a 
device that is equipped with an automatic temperature or density compensator shall have shown thereon 
that the quantity delivered has been adjusted to the quantity at the NBP of the specific cryogenic product or 
the equivalent volume of gas at NTP.  
 
UR.2.6.3.  Printed Ticket.  – Any pri nted ticket issued by a device of the computing type on which 
there is printed the total computed price, the total quantity of the delivery, or the price per unit, shall also show the other two values (either printed or in clear hand script).  
 
UR.2.6.4.  Ticket in Printing Device.  – A ticket shall not be inserted into a device equipped with a 
ticket printer until immediately before a delivery is begun, and in no case shall a ticket be in the device 
when the vehicle is in motion while on a public street, high way, or thoroughfare.  
 
UR.2.7.  Pressure of Tanks with Volumetric Metering Systems without Temperature Compensation.  – 
When the saturation pressure of the product in the vendor’s tank exceeds 240  kPa (35  psia), a correction shall be 
applied to the written invoice or printed ticket using the appropriate tables as listed in Table  N.4. Density or 
Volume Correction Factors; or the saturation pressure shall be reduced to 207  kPa (30  psia) (if this can be safely 
accomplished) prior to making a delivery.  
(Added 197 6) 
 
 
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 Section 3.35.  Milk Meters  
 
 
A. Application  
 
A.1. General.  – This code applies to devices used for the measurement of milk; generally applicable to, but not 
limited to, meters used in dairies, milk processing plants, and cheese factories, to measure incoming bulk milk.  
 A.2. Exceptions.  – This code does not apply to mass flow meters.  (Also see Section  3.37. Code for Mass Flow 
Meters.)  
(Added 1994)  
 
A.3. Additional Code Requirements. –  In addition to the requirements of this code, Milk Meters shall meet the 
requirements of Section  1.10. General Code.  
 
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A meter shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  
 
S.1.1.2.  Units.  
 
(a) A meter shall indicate, and record if the meter is equipped to record, its deliveries in terms of liters 
or gall ons.  Fractional parts of the liter shall be in terms of decimal subdivisions.  Fractional parts 
of the gallon  shall be in terms of either decimal or binary subdivisions.  
 (b) When it is an industry practice to purchase and sell milk by weight based upon 1 .03 kg/L 
(8.6 lb/gal), the primary indicating element may indicate in kilograms or pounds.  The weight 
value division shall be a decimal multiple or submultiple of 1, 2, or  5.  Fractional parts of the 
kilogram or pound shall be in decimal subdivisions.  (A lso see S.4.5. Conversion Factor.)  
 
S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated quantity and recorded 
quantity, if the meter is equipped to record, shall not exceed the equivalent of:  
 
(a) 0.5 L or 0.5 kg (1  pt or 1 lb) when measuring quantities less than or equal to 4000  L or 4000 kg 
(1000 gal or 8600 lb); or 
 
(b) 5 L or 5  kg (1  gal or 10  lb) when measuring quantities in excess of 4000  L or 4000 kg (1000  gal or 
8600 lb). 
(Amended 1989)  
 
S.1.1.4.  Advancement of Indicating  and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only by the mechanical operation of the meter.  However, a 
meter may be cleared by advancing its elements to zero, but only if:  
 
(a) the advancing move ment, once started, cannot be stopped until zero is reached; or  
 
(b) in the case of indicating elements only, such elements are automatically obscured until the 
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S.1.1.5.  Return to Zero.  – Primary indicating elements and primary recording elements, if the device is 
equipped to record, shall be readily returnable to a definite zero indication.  Means shall be provided to 
prevent the return of the primary indicating elements and the primary recording elements, if the device is so 
equipped, beyond their correct zero position.  
 
S.1.1.6.  Indication of Measurement.  – A meter shall be constructed to show automatically its initial 
zero condition and the volume measured up to the nominal capacity o f the device.  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the  minimum clear interval between graduations, and the width of main graduations shall be 
not more than 50  % greater than the width of subordinate graduations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 S.1.2.3.  Clear Interval between Graduations.  – The clear interval shall be not less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the indicator is continuous, at the point of widest separation of the graduations.  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length ass ociated with the graduations.  
 S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indic ator and the ends of the graduations, measured along the line of graduations, shall be not more 
than 1.0  mm (0.04  in). 
 
S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not gre ater than:  
 
(a) the width of the narrowest graduation ;* and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 (b) the width of the minimum clear interval between graduations.  
 When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 S.1.3.4.  Clearance.  – The clearance between t he index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 S.1.3.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
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 S.1.3.6.  Travel of Indicator.  – If the most sensitive element of the primary indicating element utilizes 
an indicator and graduations, the relative movement of these parts corresponding to the smallest indicated 
value shall be not less than 5  mm (0.20 in). 
 
S.1.4.  Computing -Type Devices.  
 
S.1.4.1.  Display of Unit Price.  – In a device of the computing type, means shall be provided for 
displaying on the outside of the device, and in close proximity to the display of the total computed price, 
the price per unit at which the device is set to compute.  
 
S.1.4.2.  Printed Ticket.  – If a computing -type device issues a printed ticket which displays the total 
computed price, the ticket also shall have printed clearly thereon  the total quantity of the delivery, the 
appropriate fraction of the quant ity, and the price per unit of quantity.  
(Amended 1989)  
 
S.1.4.3.  Money -Value  Computations.  – Money- value computations shall be of the full- computing type 
in which the money- value at a single unit price, or at each of a series of unit prices, shall be computed for 
every delivery within either the range of measurement of the device or the range o f the computing 
elements, whichever is less.  Value graduations shall be supplied and shall be accurately positioned.  The 
value of each graduated interval shall be 1  cent.  
 
S.1.4.4.  Money -Values, Mathematical Agreement.  – Any digital money -value indicatio n and any 
recorded money -value on a computing -type device shall be in mathematical agreement with its associated 
quantity indicating or representation to within 1  cent of money -value.  
 
S.2. Design of Measuring Elements.  
 
S.2.1.  Vapor Elimination.  – A metering system shall be equipped with an effective vapor eliminator or 
other effective means automatic in operation to prevent the passage of vapor and air through the meter.  Vent 
lines from the air (or vapor) eliminator shall be made of metal tubin g or some other suitably rigid material.  
 
S.2.2.  Maintaining Flooded Condition.  – The vent on the vapor eliminator shall be positioned or 
installed in such a manner that the vapor eliminator cannot easily be emptied between uses.  
 S.2.3.  Provision for Seal ing. – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before an adjustment or interchange may be made of any:  
 
(a) measuring  element or indicating element;  
 
(b) adjustable  element for controlling delivery rate, when such rate tends to affect the accuracy of 
deliveries; and  
 
(c) metrological parameter that will affect the metrological integrity of the device or system.  
 
When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 
[Audit trails shall use the format set forth in Table  S.2.3. Categories of Device and Methods of Sealing ]* 
[*Nonretroactive as of January  1, 1995]  
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 Table S.2.3.  
Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for  configuration 
parameters.  
Category  2:  Remote configuration capability, but access 
is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  The hardware enabling access for remote communication 
must be on -site.  The hardware must be sealed using a 
physical seal or an event counter for calibration 
parameters an d an event counter for configuration 
parameters.  The event counters may be located either at 
the individual measuring device or at  the system 
controller; however, an adequate number of counters 
must be provided to monitor the calibration and 
configuration parameters of the individual devices at a 
location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of the 
information through an on -site device.  
Category  3:  Remo te configuration capability access may 
be unlimited or controlled through a software switch 
(e.g., password) . 
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if capable 
of printing in this mode or shall not operate while in this 
mode.  
 An event logger is required in the device; it must include 
an event counter (000 to 999), the parameter ID, the date 
and time of the change, and the new value of the 
parameter.  A printed copy of the information must be 
available through the device or through another on -site 
device.  The event logger shall have a capacity to retain 
records equal to 10 times the number of sealable  
parameters in the device, but not more than 1000 records 
are required.  ( Note:   Does not r equire 1000 changes to 
be stored for each parameter.)  
[Nonretroactive  as of January  1, 1995]  
(Table Added 2006)  
 
S.2.4.  Directional Flow Valves.  – Valves intended to prevent reversal of flow shall be automatic in 
operation.  
 
S.3. Design of Intake Lines.  
 
S.3.1.  Diversion of Liquid to be Measured.  – No means shall be provided by which any liquid can be 
diverted from the supply tank to the receiving tank without being measured by the device.  A manually 
controlled outlet that may be opened for purging or dr aining the measuring system shall be permitted.  Effective 
means shall be provided to prevent passage of liquid through any such outlet during normal operation of the measuring system.  
(Amended 1994)  
 
S.3.2.  Intake Hose.  – The intake hose shall be:  
 
(a) of the dry- hose type;  
 
(b) adequately  reinforced;  
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 (c) not more than 6  m (20  ft) in length unless it can be demonstrated that a longer hose is essential to 
permit transfer from a supply tank; and  
 
(d) connected  to the pump at horizontal or above to permit complete drainage of the hose.  
(Amended 1991)  
 
S.4. Marking Requirements.  
 
S.4.1.  Limitation of Use.  – If a meter is intended to measure accurately only liquids having particular 
properties, or to measure accurately only under specific installation or operating conditions, or to measure 
accurately only when used in conjunction with specific accessory equ ipment, these limitations shall be clearly 
and permanently stated on the meter.  
 
S.4.2.  Discharge Rates.  – A meter shall be marked to show its designed maximum and minimum 
discharge rates.  The marked minimum discharge rate shall not exceed 20  % of the mar ked maximum discharge 
rate. 
 
Note:  Also see example in Section 3.30. Liquid- Measuring Devices Code, paragraph S.4.4.1. Discharge Rates.  
(Added 2003)  
 
S.4.3.  Measuring Components.  – All components that affect the measurement of milk that are 
disassembled fo r cleaning purposes shall be clearly and permanently identified with a common serial number.  
 
S.4.4.  Flood Volume.  – When applicable, the volume of product (to the nearest minimum division of the 
meter) necessary to flood the system when dry shall be clear ly, conspicuously, and permanently marked on the 
air eliminator.  
 
S.4.5.  Conversion Factor.  – When the conversion factor of 1.03 kg/L (8.6  lb/gal) is used to convert the 
volume of milk to weight, the conversion factor shall be clearly marked on  the primary  indicating element and 
recorded on the delivery ticket.  
 
N. Notes  
 
N.1. Test Liquid.  
 
(a) A meter shall be tested with the liquid to be commercially measured or with a liquid of the same general 
physical characteristics.  Following a satisfactory examination, the weights and measures official should 
attach a seal or tag indicating the product used during the test.  
(Amended 1989)  
 (b) A milk measuring system shall be tested with the type of milk to be measured when the accuracy of the 
system is affe cted by the characteristics of milk (e.g., positive displacement meters).  
(Added 1989)  
 
N.2. Evaporation and Volume Change.  – Care shall be exercised to reduce to a minimum, evaporation losses 
and volume changes resulting from changes in temperature of the  test liquid.  
 
N.2.1.  Temperature Correction.  – Corrections shall be made for any changes in volume resulting from 
the differences in liquid temperatures between time of passage through the meter and time of volumetric  
determination in the test  measure.  W hen adjustments are necessary, appropriate tables should be used.  
 
N.3. Test Drafts.  – Test drafts should be equal to at least the amount delivered by the device in one minute at its 
maximum discharge rate, and shall in no case be less than 400  L or 400 kg (100  gal or 1 000 lb). 
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N.4. Testing Procedures.  
 
N.4.1.  Normal Test s. – The “normal” test of a meter shall be made at the maximum discharge rate that 
may be anticipated under the conditions of the installation.  The “normal” test shall include a determination of 
the effectiveness of the air elimination system.  
 
N.4.1.1.  Repeatability  Tests. – Tests for repeatability  should include a minimum of three consecutive 
test drafts of approximately the same size and be conducted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2002)  
 N.4.2.  Special Tests.  – “Special” tests shall be made to develop the operating characteristics of a device 
and any special elements and accessories attached to or associat ed with the device.  Any test except as set forth 
in N.4.1. Normal Tests shall be considered a special test.  
 
N.4.3.  System Capacity.  – The test of a milk -metering system shall include the verification of the 
volume of product necessary to flood the system  as marked on the air eliminator.  
 
T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Underregistration  and to Overregistration.  – The tolerances hereinafter prescribed shall be 
applied to errors of underregistration  and errors of overregistration . 
 
T.2. Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table 1. Tolerances for 
Milk Meters.  
(Amended 1989)  
 
  Table 1.  
Tolerances for Milk Meters  
Indication  Maintenance  Acceptance  
gallons  gallons  gallons  
100 0.5 0.3 
200 0.7 0.4 
300 0.9 0.5 
400 1.1 0.6 
500 1.3 0.7 
Over 500  Add 0.002  gallon  per indicated 
gallon over 500  Add 0.001  gallon  per indicated 
gallon over 500  
(Added 1989)  
 
T.3. Repeatability . – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within the applicable tolerance.  (Also s ee N.4.1.1. Repeatability  Tests.)  
(Added 200 2) 
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 UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Plumb and Level Condition.  – A device installed in a fixed location shall be installed plumb and 
level, and the installation shall be sufficiently strong and rigid to maintain this condition.  
 
UR.1.2.  Discharge Rate.  – A meter shall be so installed that the actual maximum discharge  rate will not 
exceed the rated maximum discharge rate.  If necessary, means for flow regulation shall be incorporated in the 
installation, in which case this shall be fully effective and automatic in operation.  
 
UR.1.3.  Unit Price.  – There shall be displa yed on the face of a device of the computing type the unit price at 
which the device is set to compute.  
 
UR.1.4.  Intake Hose.  – The intake hose shall be so installed as to permit complete drainage and that all 
available product  is measured following each transfer.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements 
(visual), and the primary recording elements when these are returnable to zero, shall be returned to zero before 
each transfer . 
 
UR.2.2.  Printed Ticket.  – Any printed ticket issued by a device of the computing type on which there is 
printed the total computed price, the total quantity, or the price per unit of quantity, shall also show the other 
two values (either printed or in c lear script).  
(Amended 1989)  
 
UR.2.3.  Ticket in Printing Device.  – A ticket shall not be inserted into a device equipped with a ticket 
printer until immediately before a transfer is begun.  If the meter is mounted on a vehicle, in no case shall a ticket be in the device when the vehicle is in motion while on a public s treet, highway, or thoroughfare.  
 UR.2.4.  Credit for Flood Volume.  – The volume of product necessary to flood the system as marked on the 
air eliminator shall be individually recorded on the ticket of each transfer affected.  
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 Section 3.36.  Water Meters  
 
 
A. Application  
 
A.1. General . – This code applies to devices used for the measurement of water; generally applicable to, but not 
limited to, utilities type meters installed in residences or business establishments and meters installed in batching 
systems.  
(Amended 2002)  
 A.2. Exceptions . – This code does not apply to:  
 
(a) water  meters mounted on vehicle tanks (for which see Section 3.31. Vehicle- Tank Meters); or  
 
(b) mass  flow meters.  (Also see Section 3.37. Mass Flow Meters.)  
(Added 1994)   
 A.3. Additional Code Requirements . – In addition to the requirements of this code, Water Meters shall meet the 
requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A water meter shall be equipped with a primary indicating element and may also be 
equipped with a primary recording element.  Such elements shall be visible at the point of measurement or 
be stored in non- volatile and non -resettable  mem ory.  The display may be remotely located provided it is 
readily accessible to the customer.  
(Amended 2002)  
 
S.1.1.2.  Units.  – A water meter shall indicate and record, if the device is equipped to record, its 
deliveries in terms of liters, gallons or cubic feet or binary or decimal subdivisions thereof except batch 
plant meters , which shall indicate deliveries in terms of liter s, gallons or decimal subdivisions of the liter or 
gallon only.  
 S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated delivery and recorded 
delivery, if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) 50 L (10  gal or 1 ft
3) on utility type meters,  sizes 1  in and smaller; or  
 (b) 500 L (100 gal or 10  ft
3) on utility -type meters , sizes 1½  in and 2  in; or  
 (c) 0.2 L (
1/10 gal or 1/100 ft3) on batching meters delivering less than 375  L/min (100 gal/min  or 
13 ft 3/min); or 
 
(d) 5 L (1 gal or 1/10 ft3) on batching meters delivering 375  L/min (100 gal/min  or 13 ft3/min) or more.  
 (Amended 2009)  
 
S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only by the mechanical operation of the device.  
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 S.1.1.5.  Return to Zero.  – If the meter is so designed that the primary indicating elements are readily 
returnable to a defini te zero indication, means shall be provided to prevent the return of these elements 
beyond their correct zero position.  
 
S.1.1.6.  Proving indicator. –  Utility -type meters shall be equipped with a proving indicator.  The 
individual graduations on a mechanic al (analog) proving indicator shall indicate volumes no larger than 1/100 
of the value of the smallest unit of indicated delivery required in S.1.1.3.  Value of Smallest Unit.  For electronic (digital) proving indications, the smallest unit of volume displayed shall be no larger than 
1/1000 of 
the value of the smallest unit of indicated delivery required in S.1.1.3.  
(Added 2009)  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 
S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the width of main graduations shall be 
not more than 50  % greater than the width of subordina te graduations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 
S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall not be less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall b e made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the indicator is continuous, at the point of widest separation of the graduations.  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 
S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with whic h it is used, 
the width of the minimum clear interval between graduations, and the width of main graduations shall be 
not more than 50  % greater than the width of subordinate graduations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in widt h. 
 
S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall not be greater than:  
 
(a) the width of the narrowest graduation ;* and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 (b) the width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 S.1.3.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 S.1.3.5.  Parallax.  – Parall ax effects shall be reduced to the practicable minimum.  
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 S.2. Design of Measuring Elements.  
 
S.2.1.  Provision for Sealing.  – Adequate provision shall be made for applying security seals in such a 
manner that no adjustment or interchange may be made of:  
 
(a) any measurement elements; and  
 
(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries.  
 
The adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 
S.2.2.  Batching  Meters Only.  
 
S.2.2.1.  Air Elimination.  – Batching meters shall be equipped with an effective air eliminator.  
 
S.2.2.2.  Directional Flow Valves.  – Valves intended to prevent reversal of flow shall be automatic in 
operation.  
 
S.2.3.  Multi -Jet Meter Identification.  – Multi- Jet water meters shall be clearly and permanently 
marked as such on the device or identified on the Certificate of Conformance.  
(Added 2003)  
 
S.3. Markings  
 
S.3.1.  Location of Marking Information; Utility Type Meters.  – All required markings, including those 
required by G -S.1. Identification, shall be either on the meter body or primary indicator.  
[Nonretroactive  as of January 1, 2013]  
(Added 2012)  
 
N. Notes  
 
N.1. Test Liquid.  – A meter shall be tested with water.  
 
N.2. Evaporation and Volume Change.  – Care shall be exercised to reduce to a minimum, evaporation losses 
and volume changes resulting from changes to  temperature of the test liquid.  
 N.3. Test Drafts.  – Test drafts should be equal to at least the amount delivered by the device in two  minutes and in 
no case less than the amount delivered by the device in one minute at the actual maximum flow rate developed by 
the installation.  The test draft sizes show n in Table  N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests, 
shall be followed as closely as possible.  
(Amended 2003)  
 
N.4. Testing Procedures.  
 
N.4.1.  Normal Tests.  – The normal test of a meter shall be made at the maximum discharge rate 
deve loped by the installation.  Meters with maximum gallon per minute ratings higher than the values specified 
in Table  N.4.1. Flow Rate and Draft Size for Water Meters Normal Tests may be tested up to the meter rating, 
with meter indications no less than thos e shown.  
(Amended 1990, 2002, and 2003)  
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 Table N.4.1.  
Flow Rate and Draft Size for Water Meters Normal Tests  
Meter Size 
(inches)  Rate of Flow  
(gal/min)  Maximum Rate  
Meter Indication/Test Draft  
gal ft3 
Less than 5/8    8   50    5 
    5/8  15   50    5 
    ¾  25   50    5 
1  40  100  10 
   1½  80  300  40 
2 120  500  40 
3 250  500  50 
4 350 1000  100 
6 700 1000  100 
(Table Added 2003)  
 
N.4.1.1.  Repeatability Tests. –  Tests for repeatability should include a minimum of three consecutive 
test drafts of approximately the same size and be conducted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the results obtained.  
(Added 2002)  
 
N.4.2.  Speci al Tests.  – Special tests to develop the operating characteristics of meters may be made 
according to the rates and quantities shown in Table  N.4.2.a. Flow Rate and Draft Size for Water Meters Special 
Tests  and Table N.4.2.b.  Flow Rate and Draft Size for Utility Type Water Meters Special Tests . 
(Amended 2003 and 2010)  
 
Table N.4.2.a.  
Flow Rate and Draft Size for Batching Water Meters Special Tests  
Meter Size 
(inches)  Intermediate Rate  Minimum Rate  
Rate of Flow  
(gal/min)  Meter Indication/Test Draft  Rate  of Flow  
(gal/min)  Meter Indication/Test Draft  
gal ft3 gal ft3 
Less than or 
equal to 5/8   2  10   1     ¼   5 1 
    ¾   3  10   1     ½   5 1 
1   4  10   1     ¾   5 1 
   1½   8  50   5    1½ 10 1 
2 15  50   5 2 10 1 
3 20  50   5 4 10 1 
4 40 100 10 7 50 5 
6 60 100 10 12 50 5 
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Table N.4.2.b.  
Flow Rate and Draft Size for Utility Type Water Meters Special Tests  
Meter Size 
(inches)  Intermediate Rate Minimum Rate  
Rate of Flow  
(gal/min)  Meter Indication/Test Draft  Rate of Flow  
(gal/min)  Meter Indication/Test Draft  
gal ft3 gal ft3 
Less than 5/8 2 10 1 ¼ 5 1 
5/8 2 10 1 ¼ 5 1 
5/8 x ¾ 2 10 1 ¼ 5 1 
¾ 3 10 1 ½ 5 1 
1 4 10 1 ¾ 5 1 
1½ 8 100 10 1½ 100 10 
2 15 100 10 2 100 10 
(Table Added 2010)  
 
N.4.3.  Batching Meter Tests.  – Tests on batching meters should be conducted at the maximum and 
intermediate rates only.  
 
T. Tolerances  
 T.1. Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table T.1. Accuracy 
Classes and Tolerances for Water Meters.  
(Amended 2003)  
 
Table T.1.  
Accuracy Classes and Tolerances for Water Meters  
Accuracy 
Class  Application  Acceptance 
Tolerance Maintenance 
Tolerance Tolerance for Special 
Tests Conducted at the 
Minimum Flow Rate  
1.5 Water, Other 
Than Multi -Jet 
Water Meters  Overregistration  1.5 %  1.5 %  1.5 %  
Underregistration  1.5 %  1.5 %  5.0 %  
1.5 Water, Multi-
Jet Water 
Meters  Overregistration  1.5 %  1.5 %  3.0 %  
Underregistration  1.5 %  1.5 %  3.0 %  
(Table Added 2003)  
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 T.1.1.  Repeatability . – When multiple tests are conducted at approximately the same flow rate, each test 
shall be within the applicable tolerances and the range of test results shall not exceed the values shown in Table T.1.1. Repeatability . 
 (Added 2002) (Amended 2010)  
 
 
Table T.1.1.  
Repeatability  
 Batching Meters  Utility -Type Meters  
Normal Flow Rates  0.6 % 0.6 % 
Intermediate Flow Rates  0.6 % 2.0 % 
Minimum Flow Rate  1.3 % 4.0 % 
 (Table Added 2010)  
 
UR. User Requirements  
 
UR.1.  Batching Meters Only.  
 
UR.1.1.  Strainer.  – A filter or strainer shall be provided if it is determined that the water contains excessive 
amounts of foreign material.  
 
UR.1.2.  Siphon Breaker.  – An automatic siphon breaker or other effective means shall be installed in the 
discharge piping at the highest point of outlet, in no case below the top of the meter, to prevent siphoning of the meter and permit rapid drainage of the pipe or hose.  
 
UR.1.3.  Provision for Testing.  – Acceptable provisions for testing shall be incorporated into all meter 
systems.  Such provisions shall include a two -way valve, or manifold valving, and a pipe or hose installed in the 
discharge line accessible to the proper positioning of the test meas ure. 
 
UR.2.  Accessibility of Customer Indication.  – An unobstructed standing space of at least 76 cm (30  in) wide, 
91 cm (36  in) deep, and 198 cm (78  in) high shall be maintained in front of an indication intended for use by the 
customer to allow for readi ng the indicator.  The customer indication shall be readily observable to a person located 
within the standing space without necessity  of a separate tool or device.  
(Added 2008)  
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 Section 3.37.  Mass Flow Meters 
 
 
A. Application  
 
A.1. Liquids.  – This code applies to devices that are designed to dynamically measure the mass, or the mass and 
density of liquids.  It also specifies the relevant examinations and tests that are to be conducted.  
(Amended 1997)  
 A.2. Vapor (Gases).  – This code applies to devices that are designed to dynamically measure the mass of 
hydrocarbon gas in the vapor state.  Examples of these products are propane, propylene, butanes, butylenes , ethane, 
methane, natural gas and any other hydrocarbon gas/air mix.  
 A.3. Additional  Code Requirements . – In addition to the requirements of this code, Mass Flow Meters shall meet 
the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Indicating and Recording Elements.  
 
S.1.1.  Indicating Elements.  – A measuring assembly shall include an indicating element.  Indications 
shall be clear, definite, accurate, and easily read under normal conditions of operation of the instrument.  
 
S.1.2.  Natural Gas Dispensers.  – Except for fleet sales and other price contract sales, a natural gas 
dispenser used to refuel vehicles shall be of the computing type and shall indicate the quantity, the unit price, and the total price of each delivery.  The dispenser shall display the mass measured for each transaction either continuously on an external or internal display accessible during the inspection and test of the dispenser, or 
display the quantity in mass units by using controls  on the device.  
 
(Added 1994)(Amended 2013)  
 
S.1.3.  Units.  
 
S.1.3.1.  Units of Measurement.  – Deliveries shall be indicated and recorded in grams, kilograms, 
metric tons, pounds, tons, and/or liters, gallons, quarts, pints and decimal subdivisions thereof.  The 
indication of a delivery shall be on the basis of apparent mass versus a density of 8 .0 g/cm
3.  The volume 
indication shall be based on the mass measurement and an automatic means to determine and correct for changes in product density.  
(Amended 1993 and 1997)  
 
S.1.3.1.1.  Natural Gas Used as an Engine Fuel. –  When natural gas is dispensed as an engine 
fuel, the delivered quantity shall be indicated  in “gasoline liter equivalent (GLE) units” or “gasoline gallon 
equivalent (GGE) units , 
 
(b)  “diesel liter equivalent (DLE) units” or “diesel gallon equivalent (DGE) units: ( .” (Also see 
definitions.)  
(Added 1994)  (Amended 2013)  
 
S.1.3.2.  Numerical Value of Quantity -Value Divisions.  – The value of a scale interval shall be 
equal  to: 
 
(a) 1, 2, or  5; or 
 
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S.1.3.3.  Maximum Value of Quantity- Value Divisions.  
 
(a) The maximum value of the quantity- value division for liquids shall not be greater than 0.2  % of 
the minimum measured quantity.  
 
(b) For dispensers of compressed natural gas used to refuel vehicles, the value of the division for the 
gasoline liter e quivalent shall not exceed 0.01  GLE; the division for gasoline gallon equivalent 
(GGE) shall not exceed 0.001  GGE.  The maximum value of the mass division shall not exceed 
0.001  kg or 0.001  lb. 
(Amended 1994)  
 
S.1.3.4.  Values Defined.  – Indicated values sh all be adequately defined by a sufficient number of 
figures, words, symbols, or combinations thereof.  A display of “zero” shall be a zero digit for all displayed 
digits to the right of the decimal mark and at least one to the left.  
 
S.2. Operating Requirements.  
 
S.2.1.  Return to Zero.  – Except for measuring assemblies in a pipeline:  
 
(a) One indicator and the primary recording elements, if the device is equipped to record, shall be 
provided with a means for readily returning the indication to zero either automatically or manually.  
 
(b) It shall not be possible to return primary indicating elements, or primary recording elements, beyond 
the correct zero position.  
(Amended 1993)  
 
S.2.2.  Indicator Reset Mechanism.  – The reset mechanism for the indicating element shall not be 
operable during a delivery.  Once the zeroing operation has begun, it shall not be possible to indicate a value other than the latest measurement, or “zeros” when the zeroing operation has been completed.  
 
S.2.3.  Non-resettable Indicator.  – An instrument may also be equipped with a non -resettable  indicator 
if the indicated values cannot be construed to be the indicated values of the resettable  indicator for a delivered 
quantity.  
 
S.2.4.  Provisions for Power Loss.  
 
S.2.4.1.  Transaction Information.  – In the event of a power loss, the information needed to complete 
any transaction in progress at the time of the power loss (such as the quantity and unit price, or sales price) 
shall be determinable for at least 15  minutes at the disp enser or at the console if the console is accessible to 
the customer.  
(Added 1993)  
 
S.2.4.2.  User Information.  – The device memory shall retain information on the quantity of fuel 
dispensed  and the sales price totals during power loss.  
(Added 1993)  
 
S.2.5.  Display of Unit Price and Product Identity.  
 
S.2.5.1.  Unit Price.  – A computing or money- operated device shall be able to display on each face the 
unit price at which the device is set to compute or to dispense.  
(Added 1993)  
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 S.2.5.2.  Product Identity.  – A device shall be able to conspicuously display on each side the identity of 
the product being dispensed.  
(Added 1993)  
 
S.2.5.3.  Selection of Unit Price. –  Except for dispensers used exclusively for fleet sales, other price 
contract sales, and truck refueling (e.g., truck stop dispensers used only to refuel trucks), when a product or grade is offered for sale at more than one unit price through a computing device, the selection of the unit price shall be made prior to delivery using controls  on the device or other customer -activated controls.  A 
system shall not permit a change to the unit price during delivery of a product.  
[Nonretroactive  as of January  1, 1998]  
(Added 1997)  
 
S.2.5.4.  Agreement Between Indications. –  When a quantity value indicated or recorded by an auxiliary 
element is a derived or computed value based on data received from a retail motor -fuel dispenser, the 
value may differ from the quantity value displayed on the dispenser, provided the following conditions are 
met: 
 
(a) all total money -values for an individual sale that are indicated or recorded by the system agree; 
and 
 
(b) within  each element the values indicated or recorded meet the formula (quantity x unit price = 
total sales price) to the closest cent.  
[Nonretroactive  as of January  1, 1998]  
(Added 1997)  
 
S.2.6.  Money -Value  Computations.  – A computing device shall compute the to tal sales price at any 
single -purchase unit price (i.e., excluding fleet sales, other price contract sales, and truck stop dispensers used 
only to refuel trucks) for which the product being measured is offered for sale at any delivery possible within 
eithe r the measurement range of the device or the range of the computing elements, whichever is less.  
(Added 1993)  
 
S.2.6.1.  Auxiliary Elements.  – If a system is equipped with auxiliary indications, all indicated money -
value and quantity divisions of the auxili ary element shall be identical with those of the primary element.  
(Added 1993)  
 
S.2.6.2.  Display of Quantity and Total Price.  – When a delivery is completed, the total price and 
quantity for that transaction shall be displayed on the face of the dispenser for at least 5  minutes or until the 
next transaction is initiated by using controls  on the device or other user -activated con trols.  
(Added 1993)  
 
S.2.7.  Recorded Representations, Point -of-Sale Systems.  – The sales information recorded by  cash 
registers when interfaced with a retail motor -fuel dispenser shall contain the following information for products 
delivered by the dispens er: 
 
(a) the total volume of the delivery;  
 
(b) the unit price;  
 
(c) the total computed price; and  
 
(d) the product identity  by name, symbol, abbreviation, or code number.  
[Nonretroactive  as of January  1, 1986]  
(Added 1993)  
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 S.2.8.  Indication of Delivery.  – The device shall automatically show on its face the initial zero condition 
and the quantity delivered (up to the nominal capacity).  However, the first 0.03 L (0.009 gal) of a delivery and 
its associated total sales price need not be indicated.  
[Nonretroactive  as of January  1, 1998]  
(Added 1997)  
 
S.3. Measuring Elements and Measuring Systems.  
 
S.3.1.  Maximum and Minimum Flow -Rates.  
 
(a) The ratio of the maximum to minimum flow -rates specified by the manufacturer for devices 
measuring liquefied gases shall be 5:1 or greater.  
 
(b) The ratio of the maximum to minimum flow -rates specified by the manufacturer for devices 
measuring other than liquefied gases shall be 10:1 or greater.  
 
S.3.2.  Adjustment  Means.  – An assembly shall be provided with the means to change the ratio between 
the indicated quantity and the quantity of liquid measured by the assembly.  A bypass on the measuring assembly shall not be used for these means.  
 
S.3.2.1.  Discontinuous Adjusting  Means.  – When the adjusting means changes  the ratio between the 
indicated quantity and the quantity of measured liquid  in a discontinuous manner, the consecutive values of 
the ratio shall not differ by more than  0.1 %. 
 
S.3.3.  Vapor Elimination.  – A liqui d-measuring instrument or measuring system shall be equipped with 
an effective vapor or air eliminator or other effective means, automatic in operation, to prevent the measurement 
of vapor and air.  Vent lines from the air or vapor eliminator shall be made of metal tubing or some other 
suitable rigid material.  
(Amended 1999)  
 
S.3.3.1.  Vapor Elimination on Loading Rack Liquid Metering Systems.  
 
(a) A loading rack liquid metering system shall be equipped with a vapor or air eliminator or other 
automatic means to prevent the passage of vapor and air through the meter unless the system is 
designed or operationally controlled by a method, approved by the weights and measures 
jurisdiction having statutory authority over the device, such that neither air nor vapor can enter the 
system.  
 
(b) Vent lines from the air or vapor eliminator (if present) shall be made of metal tubing or other rigid material.  
(Added 1995)  
 
S.3.4.  Maintenance of Liquid State.  – A liquid -measuring device shall be installed so that the measured 
product  remains in a liquid state during passage through the instrument.  
 
S.3.5.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or physically applying security seals in such a manner that no adjustment or 
interchange may be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries;  
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 (c) the zero adjustment mechanism; and  
 
(d) any metrological parameter that will affect the metrological integrity of the device or system.  
 
When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 [Audit trails shall use the format set forth in Table  S.3.5. Categories of Device and Methods of Sealing ]* 
[*Nonretroactive as of January  1, 1995]  
(Amended 1992, 1995, and 2006)  
 
Table S.3.5.  
 Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for  configuration 
parameters.  
Category  2:  Remote configuration capability, but 
access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the 
remote configuration mode and record such message 
if capable of printing in this mode or shall not 
operate while in this mode.  [The hardware enabling access for remote 
communication must be on- site.  The hardware must be 
sealed using a ph ysical seal or an event counter for 
calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or at  
the system controller; however, an adequate number of 
counters must be provided to monitor the calibration and 
configuration parameters of the individual devices at a 
location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of the 
information through an on -site device. ]* 
[*Nonretroactive as of January  1, 1996]  
Category  3:  Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password).  
[Nonretroactive  as of January  1, 1995]  
 
The device shall clearly indicate that it is in the 
remote configuration mode and record such message 
if capable of printing in this mode or shall not 
operate while in this mode.  
[Nonretroactive  as of January  1, 2001]  An event logger is required in the device; it must include 
an event counter (000 to 999), the parameter ID, the date 
and time of the change, and the new value of the 
parameter.  A printed copy of the information must be 
available through the device or through another on- site 
device.  The event logger shall have a capacity to retain 
records equal to 10 times the number of sealable  
parameters in the device, but not more than 1000 records 
are required.  (Note:   Does not require 1000 changes to 
be stored for each parameter.)  
[Nonretroactive  as of January  1, 1995]  
(Table Added 1995) (Amended 1995, 1998, 1999, and 2006)  
 
S.3.6.  Automatic Density Correction.  
 
(a) An automatic means to determine and correct for changes in product density shall be incorporated in  
any mass flow metering system that is affected by changes in the density of the product being 
measured.  
 
(b) Volume -measuring devices with automatic temperature compensation used to measure natural gas as a 
motor vehicle engine fuel shall be equipped with an automatic means to determine and correct for 3.37.  Mass Flow Meters   Handbook 44 –  20152016  
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 changes in product density due to changes in the temperature, pressure, and composition of the 
product.  
(Amended 1994 and 1997)  
 
S.3.7.  Pressurizing the Discharge Hose.  – The discharge hose for compressed natural gas shall 
automatically pressurize prior to the device beginning to register the delivery.  
(Added 1993)  
 
S.3.8.  Zero -Set-Back Interlock, Retail Motor -Fuel Devices.  – A device shall be constructed so that:  
 
(a) after a delivery cycle has been completed by moving the starting lever to any position that 
shuts off the device, an automatic interlock prevents a subsequent delivery until the indicating 
elements, and recording elements if the device is equipped and activated  to record, have been 
returned to their zero positions; 
 
(b) the discharge nozzle cannot be returned to its designed hanging position (that is, any position 
where the tip of the nozzle is placed in its designed receptacle and the lock can be inserted) 
until th e starting lever is in its designed shut -off position and the zero- set-back interlock has 
been engaged; and  
 
(c) in a system with more than one dispenser supplied by a single pump, an effective automatic 
control valve in each dispenser prevents product from be ing delivered until the indicating 
elements on that dispenser are in a correct zero position.  
(Added 1993)  
 
S.4. Discharge Lines and Valves.  
 
S.4.1.  Diversion of Measured Product.  – No means shall be provided by which any measured product 
can be diverted f rom the measuring instrument.  However, two or more delivery outlets may be permanently 
installed and operated simultaneously, provided that any diversion of flow to other than the intended receiving 
receptacle cannot be readily accomplished or is readily apparent.  Such means include physical barriers, visible valves, or indications that make it clear which outlets are in operation, and explanatory signs if deemed 
necessary.  
 
An outlet that may be opened for purging or draining the measuring system, or for  recirculating product  if 
recirculation  is required in order to maintain the product in a deliverable state shall be permitted.  Effective 
automatic means shall be provided to prevent the passage of liquid through any such outlet during normal 
operation of  the measuring system and to inhibit meter indications (or advancement of indications) and recorded 
representations while the outlet is in operation.  
(Amended 2002 and 2006)  
 S.4.2.  Pump -Discharge Unit.  – A pump -discharge unit for liquids equipped with a flexible discharge 
hose shall be of the wet -hose type.  
(Added 1993)  
 S.4.3.  Directional Flow Valves.  – If a reversal of flow could result in errors that exceed the tolerance for 
the minimum measured quan tity, a valve or valves or other effective means, automatic in operation (and 
equipped with a pressure limiting device, if necessary) to prevent the reversal of flow shall be properly installed 
in the system.  (Also s ee N.1. Minimum Measured Quantity.)  
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 S.4.4. Discharge Valves.  – A discharge valve may be installed on a discharge line only if the system is a 
wet-hose type.  Any other shutoff valve on the discharge side of the instrument shall be of the automatic or 
semiautomatic predetermined -stop type or sh all be operable only:  
 
(a) by means of a tool (but not a pin) entirely separate from the device; or  
 
(b) by means of a security seal with which the valve is sealed open.  
 S.4.5.  Antidrain Means.  – In a wet -hose type device, effective means shall be provided to prevent the 
drainage of the hose between transactions.  
 
S.4.6.  Other Valves.  – Check valves and closing mechanisms that are not used to define the measured 
quantity shall have relief valves (if necessary) to dissipate any abnormally high pressure that  may arise in the 
measuring assembly.  
 
S.5. Markings.  – A measuring system shall be legibly and indelibly marked with the following information:  
 
(a) pattern  approval mark (i.e., type approval number);  
 
(b) name  and address of the manufacturer or his trademark and, if required by the weights and measures 
authority, the manufacturer’s identification mark in addition to the trademark;  
 
(c) model  identifier or product name selected by the manufacturer;  
 
(d) nonrepetitive  serial number;  
 
(e) the accuracy class of the meter as specified by the manufacturer consistent with Table  T.2. Accuracy 
Classes for Mass Flow Meter Applications Covered in NIST Handbook  44, Section 3.37 Mass Flow 
Meters ;* 
[*Nonretroactive as of January  1, 1995]  
(Added 1994)  
 
(f) maximum and minimum flow rates in pounds per unit of time;  
 
(g) maximum working pressure;  
 
(h) applicable  range of temperature if other than −  10 °C to +  50 °C; 
 
(i) minimum measured quantity; and  
 
(j) product  limitations, if applicable.  
 
S.5.1.  Location of  Marking Information; Retail Motor -Fuel Dispensers.  – The marking information 
required in General Code, paragraph G-S.1. Identification  shall appear as follows:  
 
(a) within  60 cm (24  in) to 150 cm (60  in) from the base of the dispenser;  
 
(b) either  internally and/or externally provided the information is permanent and easily read; and  
 
(c) on a portion of the device that cannot be readily removed or interchanged (i.e., not on a service 
access panel).  
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 Note:   The use of a dispenser key or tool to access internal marking information is permitted for retail liquid- measuring 
devices.  
[Nonretroactive  as of January  1, 2003]  
(Added 2006)  
 
S.5.2.  Marking of Diesel and Gasoline Volume Equivalent Conversion Factor.  – A device dispensing 
natural gas shall have  
  
(a) either the statement “1  Gasoline Liter Equivalent (GLE) is Equal to 0.678  kg of Natural Gas” or 
“1 Gasoline Gallon Equivalent (GGE) is Equal to 5.660  lb of natural Gas”,  
 
(b) either ther statement “1 Diesel Liter Equivalent (DLE) is Equal to 0.756 kg of Natura l Gas” or “1 
Diesel Gallon Equivalent (DGE) is Equal to 6.22 lb of Natural Gas”  
 
permanently and conspicuously marked on the face of the dispenser according to the method of sale used.  
(Added 1994)(Amended 2013)  
 S.6. Printer.  – When an assembly is equippe d with means for printing the measured quantity, the following 
conditions apply:  
 
(a) the scale interval shall be the same as that of the indicator;  
 
(b) the value of the printed quantity shall be the same value as the indicated quantity;  
 
(c) a quantity for a delivery (other than an initial reference value) cannot be recorded until the measurement 
and delivery has been completed;  
 
(d) the printer is returned to zero when the resettable  indicator is returned to zero; and  
 
(e) the printed values shall mee t the requirements applicable to the indicated values.  
 
S.6.1.  Printed Receipt.  – Any delivered, printed quantity shall include an identification number, the 
time and date, and the name of the seller.  This information may be printed by the device or pre- printed on the 
ticket.  
 
S.7. Totalizers  for Retail Motor -Fuel Devices.  – Retail motor -fuel dispensers shall be equipped with a 
nonresettable  totalizer  for the quantity delivered through the metering device.  
[Nonretroactive  as of January  1, 1998]  
(Added 1997)  
N. Notes  
 
N.1. Minimum Measured Quantity.  – The minimum measured quantity shall be specified by the manufacturer.  
 
N.2. Test Medium.  
 
N.2.1.  Liquid -Measuring Devices.  – The device shall be tested with the liquid that the device is 
intended to measure or another  liquid with the same general physical characteristics.  
 
N.2.2.  Vapor -Measuring Devices.  – The device shall be tested with air or the product to be measured.  
 
N.3. Test Drafts.  – The minimum test shall be one test draft at the maximum flow rate of the installation and one 
test draft at the minimum flow rate.  More tests may be performed at these or other flow rates.  (Also s ee 
T.3. Repeatability .) 
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 N.4. Minimum Measured Quantity.  – The device shall be tested for a delivery equal to the declared minimum 
measured quantity when the device is likely to be used to make deliveries on the order of the minimum measured 
quantity.  
 
N.5. Motor -Fuel Dispenser.  – When a device is intended for use as a liquid motor -fuel dispenser, the type 
evaluation test shall include a test for accuracy using five starts and stops during a delivery to simulate the operation of the automatic shut -off nozzle.  This test may be conducted as part  of the normal inspection and test of the meter.  
 
N.6. Testing Procedures.  
 
N.6.1.  Normal Tests.  – The normal test of a meter shall be made at the maximum discharge rate 
developed by the installation.  Any additional tests conducted at flow rates down to a nd including the rated 
minimum discharge flow rate shall be considered normal tests.  
(Added 1999)  
 
N.6.1.1.  Repeatability  Tests. – Tests for repeatability  should include a minimum of three consecutive 
test drafts of approximately the same size and be condu cted under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the 
results obtained.  
(Added 2001)  
 
N.6.2.  Special Tests.  – “Special” tests shall be made to develop the operating characteristics of a device 
and any special elements and accessories attached to or associated with the device.  Any test except as set forth in N.6.1. Normal Tests shall be considered a special tes t.  Special tests of a measuring system shall be made to 
develop operating characteristics of the measuring systems during a split compartment delivery.  (Also s ee 
Table  T.2. Accuracy Classes and Tolerances for Mass Flow Meters.)  
(Added 1999)  
 
T. Tolerances  
 
T.1. Tolerances, General.  
 
(a) The tolerances apply equally to errors of underregistration and errors of overregistration . 
 
(b) The tolerances apply to all products at all temperatures measured at any flow rate within the rated 
measuring range of the meter.  
(Amended 1999)  
 T.2. Tolerances.  – The tolerances for mass flow meters for specific liquids, gases, and applications are listed in 
Table  T.2. Accuracy Classes and Tolerances for Mass Flow Meters.  
(Amended 1994 and 1999)  
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 Table T.2.  
Accuracy Classes and Tolerances for Mass Flow Meters  
Accuracy 
Class  Application or Commodity  
Being Measured  Acceptance 
Tolerance  Maintenance 
Tolerance  Special 
Tolerance  
0.3 - Large capacity motor -fuel dispensers (maximum 
discharge flow rates greater than 100  L/min or 
25 gal/min)  
- Heated products (other than asphalt) at 
temperatures greater than 50  °C (122 °F) 
- Asphalt at temperatures equal to or below 50  °C 
(122 °F) 
- Loading rack meters  
- Vehicle -tank meters  
- Home heating oil  
- Milk and other food products  
- All other liquid applications not shown in the table 
where the minimum delivery is at least 700  kg 
(1500  lb) 0.2 %  0.3 %  0.5 %  
   0.3A  - Asphalt at temperatures greater than 50  °C 
(122 °F) 0.3 %  0.3 %  0.5 %  
0.5 - Small capacity (retail) motor -fuel dispensers  
- Agri-chemical liquids  
- All other liquid applications not shown in the table 
where the minimum delivery is less than 700 kg or 
1500 lb 0.3 %  0.5 %  0.5 %  
1.0 - Anhydrous ammonia  
- LP Gas (including vehicle -tank meters)  0.6 %  1.0 %  1.0 %  
2.0 - Compressed natural gas as a motor -fuel 1.5 %  2.0 %  2.0 %  
2.5 - Cryogenic liquid meters  
- Liquefied compressed gases other than LP Gas  1.5 %  2.5 %  2.5 %  
(Added 1994) (Amended 1999, 2001, and 2013)  
 T.3. Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within the applicable tolerance.  (Also see N.6.1.1. Repeatability Tests.)  
(Amended 1992, 1994, and 2001)  
 T.4. Type Evaluation Examinations for Liquid -Measuring Devices.  – For type evaluation examinations, the 
tolerance values shall apply under the following conditions:  
 
(a) with any one liquid within the range of liquids;  
 (b) at any one liquid temperature and pressure within the operating range of the meter; and  
 (c) at all flow rates within the range of flow rates.  
(Added 1993) (Amended 1994)  
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 UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1. Discharge Hose -Length.  – The length of the discharge hose on a retail motor -fuel device shall not 
exceed 4.6  m (15  ft) unless it can be demonstrated that a longer hose is essential to permit deliveries to be made 
to receiving vehicles or vessels.  
[Nonretroactive as of January  1, 1998]  
(Added 1997)  
 
UR.1.2.  Minimum Measured Quantity.  
 
(a) The minimum measured quantity shall be specified by the manufacturer.  
 
(b) The minimum measured quantity appropriate for a transaction may be specified by the 
weights and measures authority.  A  device may have a minimum measured quantity smaller 
than that specified by the weights and measures authority; however, the device must perform 
within the performance requirements for the declared minimum measured quantity.  
 
UR.2.  Installation Requirement s. 
 
UR.2.1.  Manufacturer’s Instructions.  – A device shall be installed in accordance with the manufacturer’s 
instructions, and the installation shall be sufficiently secure and rigid to maintain this condition.  
(Added 1997)  
 
UR.2.2.  Discharge Rate.  – A dev ice shall be installed so that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  Automatic means of flow regulation shall be incorporated in the 
installation if necessary.  
(Added 1997)  
 
UR.2.3.  Low -Flow Cut -Off Valve.  – If a metering system is equipped with a programmable or adjustable 
“low -flow cut -off” feature:  
 
(a) the low -flow cut -off value shall not be set at flow rates lower than the minimum operating flow rate 
specified by the manufacturer on the meter; and  
 
(b) the system  shall be equipped with flow control valves which prevent the flow of product and stop the 
indicator from registering product flow whenever the product flow rate is less than the low -flow 
cut-off value.  
(Added 1992)  
 
UR.3.  Use of Device.  
 
UR.3.1.  Unit Price and Product Identity for Retail Dispensers.  – The following information shall be 
conspicuously displayed or posted on the face of a retail dispenser used in direct sale:  
 
(a) except for dispensers used exclusively for fleet sales, other price contract sales, and truck refueling 
(e.g., truck stop dispensers used only to refuel trucks), all of the unit prices at which the product is 
offered for sale; and  
 
(b) in the case of a computing type or money -operated type, the unit price at which the dispenser is set to  
compute.  
(Added 1993)  
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 UR.3.2.  Vapor -Return Line.  – During any metered delivery of liquefied petroleum gas and other liquids 
from a supplier’s tank to a receiving container, there shall be no vapor -return line from the receiving container 
to the supplier’ s tank:  
 
(a) in the case of any receiving container to which normal deliveries can be made without the use of such vapor -return line; or  
 
(b) in the case of any new receiving container when the ambient temperature is below 90  °F. 
(Added 1993)  
 
UR.3.3.  Ticket Printer; Customer Ticket.  – Vehicle -mounted metering systems shall be equipped with a 
ticket printer which shall be used for all sales where product is delivered through the meter.  A copy of the ticket issued by the device shall be left with the customer at the time of delivery or as otherwise specified by the 
customer.  
(Added 1994)  
 
UR.3.4.  Printed Ticket.  – The total price, the total quantity of the delivery, and the price per unit shall be 
printed on any ticket issued by a device of the computing type and containing any one of these values.  
(Added 1993)  
 UR.3.5.  Ticket in Printing Device.  – A ticket shall not be inserted into a device equipped with a ticket 
printer until immediately before a delivery is begun, and in no case shall a ticket be in the device when the 
vehicle is in motion while on a public street, highway, or thoroughfare.  
(Added 1993)  
 UR.3.6.  Steps After Dispensing.  – After delivery to a customer from a retail motor -fuel device:  
 
(a) the starting lever shall be returned to its shutoff position  and the zero -set-back interlock engaged; and  
 
(b) the discharge nozzle shall be returned to its designed hanging position unless the primary indicating 
elements, and recording elements, if the device is equipped and activated to record, have been returned 
to a definite zero indication.  
(Added 1993)  
 UR.3.7.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements 
(visual), and the primary recording elements when these are returnable to zero, shall be returned to zero 
immediately b efore each delivery.  Exceptions to this requirement are totalizers on key -lock-operated or other 
self-operated dispensers and the primary recording element if the device is equipped to record.  
(Added 1995) (Amended 1997)  
 UR.3.8.  Return of Product to Stor age, Retail Compressed Natural Gas Dispensers.  – Provisions at the 
site shall be made for returning product to storage or disposing of the product in a safe and timely manner during or following testing operations.  Such provisions may include return lines , or cylinders adequate in size 
and number to permit this procedure.  
(Added 1998)  
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 Section 3.38.  Carbon Dioxide Liquid -Measuring Devices  
 
 
A. Application  
 
A.1. General.  – This code applies to liquid -measuring devices used for the measurement of liquid carbon dioxide.  
 
A.2. Exceptions.  – This code does not apply to devices used solely for dispensing a product in connection with 
operations in which the amount dispensed does not affect customer charges.  
 
A.3. Additional Code Requirements . – In addition to the requirements of this code, Ca rbon Dioxide Liquid -
Measuring Devices shall meet the requirements of Section 1.10. General Code.  
 
A.4. Type Evaluation.  – The National Type Evaluation Program will accept for type evaluation only those 
devices that comply with all requirements of this code . 
(Added 1998)  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General. – A device shall be equipped with a primary indicating element and may also be 
equipped with a  primary recording element.  
 
S.1.1.2.  Units. – A device shall indicate and record, if equipped to record, its deliveries in terms of 
pounds or kilograms or decimal subdivisions or multiples thereof.  
 
S.1.1.3.  Value of Smallest Unit. – The value of the smal lest unit of indicated delivery, and recorded 
delivery, if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) for small delivery devices:  
 
(1) 1 kilogram; or  
 
(2) 1 pound  
 
(b) for large delivery devices:  
 
(1) 10 kilograms; or  
 (2) 10 pounds  
 
S.1.1.4.  Advancement of Indicating and Recording Elements. – Primary indicating and recording 
elements shall be susceptible to advancement only by the normal operation of the device.  However, a 
device may be cleared by advancing its elements to  zero, but only if:  
 
(a) the advancing movement, once started, cannot be stopped until zero is reached; or  
 
(b) in the case of indicating elements only, such elements are automatically obscured until the elements reach the correct zero position.  
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 S.1.1.5.  Return to Zero. –  Primary indicating and recording elements shall be readily returnable to a 
definite zero indication.  Means shall be provided to prevent the return of primary indicating elements and of primary recording elements beyond their correct zero  position.  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length. – Graduations shall be so varied in length that they may be conveniently read.  
 
S.1.2.2.  Width. – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the mi nimum clear interval between graduations.  The width of main graduations shall be not 
more than 50 % greater than the width of subordinate graduations.  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall be not less than 1.0  mm 
(0.04  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 (b) if the ind icator is continuous, at the point of widest separation of the graduations.  
(Also see S.1.3.6. Travel of Indicator.)  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry. – The index of an indicator shall be of the same shape as the graduations at least 
throughout that portion of its length associated with the graduations.  
 
S.1.3.2.  Length. – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 S.1.3.3.  Width. – The width of the index of the indicator in relation to the series of graduations with 
which it is used shall be not greater than:  
 
(a) the width of the narrowest graduation;* and 
[*Nonretroactive as of January  1, 2002]  
(Amended 2001)  
 
(b) the width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduation shall be of the same width 
throughout the length of the index that coincides with the graduation.  
 
S.1.3.4.  Clearan ce. – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.1.3.5.  Parallax. – Parallax effects shall be reduced to the practicable minimum.  
 
S.1.3.6.  Travel of Indicator. –  If the most sensi tive element of the primary indicating element utilizes 
an indicator and graduations, the relative movement of these parts corresponding to the smallest indicated 
value shall be no less than 5  mm (0.20  in). 
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 S.1.4.  Computing -Type Devices.  
 
S.1.4.1.  Printed  Ticket. – Any printed ticket issued by a device of the computing type on which there is 
printed the total computed price shall have printed clearly thereon also the total quantity of the delivery and 
the price per unit.  
 
S.1.4.2.  Money -Value Computations.  – Money- value computations shall be of the full- computing type 
in which the money- value at a single unit price, or at each of a series of unit prices, shall be computed for 
every delivery within either the range of measurement of the device or the range o f the computing 
elements, whichever is less.  
 
The total price shall be computed on the basis of the quantity indicated when the value of the smallest 
division indicated is equal to or less than the value specified in S.1.1.3. Value of Smallest Unit.  
 
S.1.4.3.  Money -Values, Mathematical Agreement. – Any digital money -value indication and any 
recorded money -value on a computing -type device shall be in mathematical agreement with its associated 
quantity indication or representation to within 1  cent of money -value.  
 
S.2. Design of Measuring Elements.  
 
S.2.1. Vapor Elimination. –  A measuring system shall be equipped with an effective vapor eliminator 
or other effective means to prevent the measurement of vapor that will cause errors in excess of the applicable 
tolerances.  
 
S.2.2.  Reverse Flow Measurement.  – Effective means, automatic in operation, shall be installed to 
prevent reverse flow measurement.  
 
S.2.3.  Maintenance of Liquid State. –  A device shall be so designed that the product being measured 
will remain in a liquid state during passage through the device.  
 S.2.4.  Automatic Temperature or Density Compensation. – A volumetric device shall be equipped 
with automatic means for adjusting the indication and recorded representation of the measured quantity of the product to indicate or record the quantit y of the product measured in terms of pounds.  
 
S.2.5.  Provision for Sealing. – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or for physically applying a security seal in such a manner that requires the 
security seal to be broken before an adjustment or interchange may be made of:  
 
(a) any measuring or indicating element;  
 
(b) any adjustable element for controlling delivery rate when such rate tends to affect the accuracy of 
deliveries;  
 
(c) any automatic temperature or density compensating system; and  
 
(d) any metrological parameter that will affect the metrological integrity of the device or system.  
 
When applicable any adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
 
[Audit trails shall use the format set forth in Table  S.2.5. Provision for Sealing]*  
[*Nonretroactive as of January  1, 1995]  
(Amended 2006)  
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 Table S.2.5.  
Categories of Device and Methods of Sealing  
Categories of Device Methods of Sealing 
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for configuration 
parameters.  
Category  2:  Remote configuration capability, but 
access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode or shall not operate 
while in this mode.  The hardware enabling access for remote 
communication must be on- site.  The hardw are must be 
sealed using a physical seal or an event counter for 
calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or at 
the system controller; however, an  adequate number of 
counters must be provided to monitor the calibration 
and configuration parameters of the individual devices 
at a location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provide d to generate a hard copy of the 
information through an on -site device.  
Category  3:  Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password) . 
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode or shall not operate while in this mode.  
 An event logger is required in the device; it must 
include an event counter (000 to 999), the parameter 
ID, the date and time of  the change, and the new value 
of the parameter.  A printed copy of the information 
must be available through the device or through 
another on- site device.  The event logger shall have a 
capacity to retain records equal to 10 times the number of sealable parameters in the device, but not more than 
1000 records are required.  ( Note:   Does not require 
1000 changes to be stored for each parameter.)  
[Nonretroactive as of January  1, 1995]  
(Table Added 2006)  
 
S.3. Design of Discharge Lines and Discharge Line Valves.  
 
S.3.1.  Diversion of Measured Liquid. –  No means shall be provided by which any measured liquid can 
be diverted from the measuring chamber of the device or the discharge line therefrom, except that a manually 
controlled outlet that may be opened fo r purging or draining the measuring system shall be permitted.  Effective 
means shall be provided to prevent the passage of liquid through any such outlet during normal operation of the 
device and to indicate clearly and unmistakably when the valve control s are so set as to permit passage of liquid 
through such outlet.  
 
S.3.2.  Discharge Hose. –  The discharge hose of a measuring system shall be of a wet hose type with a 
shutoff valve at its outlet end.  
 
S.4. Marking Requirements.  
 
S.4.1.  Limitation of Use. –  If a measuring system is intended to measure accurately only liquids having 
particular properties, or to measure accurately only under specific installation or operating conditions, or to measure accurately only when used in conjunction with specific acce ssory equipment, these limitations shall be 
clearly and permanently marked on the device.  
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 S.4.2.  Discharge Rates. –  A meter shall be marked to show its designed maximum and minimum 
discharge rates.  The marked minimum discharge rate shall not exceed 20  % of the marked maximum discharge 
rate. 
 
Note :  Also see example in Section 3.30. Liquid- Measuring Devices Code, paragraph S.4.4.1. Discharge Rates.  
(Note Added 2003)  
 
N. Notes  
 
N.1. Test Liquid. –  The test liquid shall be carbon dioxide in a compressed liquid state.  
 N.2. Vaporization and Volume Change. –  Care shall be exercised to reduce vaporization and volume changes to 
a minimum.  When testing by weight, the weigh tank and transfer systems shal l be pre -cooled to liquid temperature 
prior to the start of the test to avoid the venting of vapor from the vessel being weighed.  
 
N.3. Test Drafts.  
 
N.3.1.  Gravimetric Test. –  Weight test drafts shall be equal to at least the amount delivered by the 
device in 2  minutes at its maximum discharge rate.  
 
N.3.2.  Transfer Standard Test. –  When comparing a meter with a calibrated transfer standard, the test 
draft shall be equal to at least the amount delivered by the device in two  minutes at its maximum discharge rate.  
 N.3.3.  Volumetric Prover Test Drafts. –  Test drafts shall be equal to at least the amount delivered in 
1 minute at its normal discharge rate.  
 
N.4. Testing Procedures.  
 
N.4.1.  Normal Tests. –  The “normal” test of a device shall be made at the maximum discharge flow rate 
developed under the conditions of installation.  Any additional tests conducted at flow rates down to and 
including one -half of the sum of the maximum di scharge flow rate and the rated minimum discharge flow rate 
shall be considered normal tests.  
 
N.4.1.1.  Repeatability Tests.  – Tests for repeatability should include a minimum of three consecutive 
test drafts of approximately the same size and be conducted  under controlled conditions where variations in 
factors such as temperature, pressure, and flow rate are reduced to the extent that they will not affect the results obtained.  
(Added 2002)  
 
N.4.2.  Special Tests. – Any test except as set forth in N.4.1. Nor mal Tests shall be considered a special 
test.  Tests shall be conducted, if possible, to evaluate any special elements or accessories attached to or 
associated with the device.  A device shall be tested at a minimum discharge rate of:  
 
(a) not less than the marked minimum discharge rate or 20  % of the maximum rated discharge rate of the 
device, whichever is less; or  
 (b) the lowest discharge rate practicable under the conditions of installation.  
 “Special” tests may be conducted to develop any characteristics of the device anticipated under the conditions 
of installation.  
 
N.4.3.  Density. – Temperature and pressure of the metered test liquid shall be measured during the test 
for the determination of density or volume correction when applicable.  The appropriate correction values shall 
apply as specified in Table N.4.4.  
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 N.4.4.  Automatic Temperature or Density Compensation. –  If a device is equipped with an automatic 
temperature or density compensator, the compensator shall be tested by comparing the quantity indicated or 
recorded by the device (with the compensator connected and operating) with the actual delivered quantity.  The 
appropriate correction values shall apply as specified in Table N.4.4.  
 
Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
− 30.00  177.89  163.19  9.127  9 - 2.0 1.989  0.266  2.9 
− 29.75  178.75  164.05  9.122  9 - 2.0 1.999  0.267  2.9 
− 29.50  179.62  164.92  9.117  9 - 1.9 2.008  0.268  2.9 
− 29.25  180.49  165.79  9.113  9 - 1.8 2.018  0.270  3.0 
− 29.00  181.36  166.67  9.108  9 - 1.7 2.028  0.271  3.0 
− 28.75  182.24  167.54  9.103  9 - 1.7 2.038  0.272  3.0 
− 28.50  183.12  168.42  9.098  9 - 1.6 2.048  0.274  3.0 
− 28.25  184.00  169.31  9.094  9 - 1.5 2.058  0.275  3.0 
− 28.00  184.89  170.19  9.089  9 - 1.4 2.067  0.276  3.0 
− 27.75  185.78  171.08  9.084  9 - 1.3 2.077  0.278  3.1 
− 27.50  186.67  171.98  9.080  9 - 1.3 2.087  0.279  3.1 
− 27.25  187.57  172.87  9.075  9 - 1.2 2.098  0.280  3.1 
− 27.00  188.47  173.77  9.070  9 - 1.1 2.108  0.282  3.1 
− 26.75  189.37  174.67  9.065  9 - 1.0 2.118  0.283  3.1 
− 26.50  190.28  175.58  9.061  9 - 1.0 2.128  0.284  3.1 
− 26.25  191.18  176.49  9.056  9 - 0.9 2.138  0.286  3.2 
− 26.00  192.10  177.40  9.051  9 - 0.8 2.148  0.287  3.2 
− 25.75  193.01  178.32  9.046  9 - 0.7 2.159  0.289  3.2 
− 25.50  193.93  179.23  9.041  9 - 0.7 2.169  0.290  3.2 
− 25.25  194.85  180.16  9.037  9 - 0.6 2.179  0.291  3.2 
− 25.00  195.78  181.08  9.032  9 - 0.5 2.190  0.293  3.2 
− 24.75  196.70  182.01  9.027  9 - 0.4 2.200  0.294  3.3 
− 24.50  197.64  182.94  9.022  9 - 0.4 2.211  0.296  3.3 
− 24.25  198.57  183.87  9.017  9 - 0.3 2.221  0.297  3.3 
− 24.00  199.51  184.81  9.013  9 - 0.2 2.232  0.298  3.3 
− 23.75  200.45  185.75  9.008  9 - 0.1 2.243  0.300  3.3 
− 23.50  201.39  186.70  9.003  9 - 0.0 2.253  0.301  3.3 
− 23.25  202.34  187.64  8.998  9 - 0.0 2.264  0.303  3.4 
− 23.00  203.29  188.60  8.993  8 - 15.9 2.275  0.304  3.4 
− 22.75  204.25  189.55  8.989  8 - 15.8 2.286  0.306  3.4 
− 22.50  205.20  190.51  8.984  8 - 15.7 2.296  0.307  3.4 
− 22.25  206.16  191.47  8.979  8 - 15.7 2.307  0.308  3.4 Handbook 44 –  20152016   3.38.  Carbon Dioxide Liquid -Measuring Devices  
  Markup Copy 
  Agency No. 209.02  
 
 Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
− 22.00  207.13  192.43  8.974  8 - 15.6 2.318  0.310  3.5 
− 21.75  208.09  193.40  8.969  8 - 15.5 2.329  0.311  3.5 
− 21.50  209.06  194.37  8.964  8 - 15.4 2.340  0.313  3.5 
− 21.25  210.04  195.34  8.959  8 - 15.4 2.351  0.314  3.5 
− 21.00  211.02  196.32  8.955  8 - 15.3 2.362  0.316  3.5 
− 20.75  212.00  197.30  8.950  8 - 15.2 2.374  0.317  3.5 
− 20.50  212.98  198.28  8.945  8 - 15.1 2.385  0.319  3.6 
− 20.25  213.97  199.27  8.940  8 - 15.0 2.396  0.320  3.6 
− 20.00  214.96  200.26  8.935  8 - 15.0 2.407  0.322  3.6 
− 19.75  215.95  201.26  8.930  8 - 14.9 2.419  0.323  3.6 
− 19.50  216.95  202.25  8.925  8 - 14.8 2.430  0.325  3.6 
− 19.25  217.95  203.25  8.920  8 - 14.7 2.441  0.326  3.7 
− 19.00  218.95  204.26  8.915  8 - 14.6 2.453  0.328  3.7 
− 18.75  219.96  205.27  8.911  8 - 14.6 2.464  0.329  3.7 
− 18.50  220.97  206.28  8.906  8 - 14.5 2.476  0.331  3.7 
− 18.25  221.99  207.29  8.901  8 - 14.4 2.488  0.333  3.7 
− 18.00  223.01  208.31  8.896  8 - 14.3 2.499  0.334  3.8 
− 17.75  224.03  209.33  8.891  8 - 14.3 2.511  0.336  3.8 
− 17.50  225.05  210.36  8.886  8 - 14.2 2.523  0.337  3.8 
− 17.25  226.08  211.38  8.881  8 - 14.1 2.534  0.339  3.8 
− 17.00  227.11  212.42  8.876  8 - 14.0 2.546  0.340  3.8 
− 16.75  228.15  213.45  8.871  8 - 13.9 2.558  0.342  3.9 
− 16.50  229.18  214.49  8.866  8 - 13.9 2.570  0.344  3.9 
− 16.25  230.23  215.53  8.861  8 - 13.8 2.582  0.345  3.9 
− 16.00  231.27  216.58  8.856  8 - 13.7 2.594  0.347  3.9 
− 15.75  232.32  217.62  8.851  8 - 13.6 2.606  0.348  3.9 
− 15.50  233.37  218.68  8.846  8 - 13.5 2.618  0.350  4.0 
− 15.25  234.43  219.73  8.841  8 - 13.5 2.630  0.352  4.0 
− 15.00  235.49  220.79  8.836  8 - 13.4 2.643  0.353  4.0 
− 14.75  236.55  221.86  8.831  8 - 13.3 2.655  0.355  4.0 
− 14.50  237.62  222.92  8.826  8 - 13.2 2.667  0.357  4.0 
− 14.25  238.69  223.99  8.821  8 - 13.1 2.680  0.358  4.1 
− 14.00  239.76  225.07  8.816  8 - 13.1 2.692  0.360  4.1 
− 13.75  240.84  226.14  8.811  8 - 13.0 2.704  0.362  4.1 
− 13.50  241.92  227.22  8.806  8 - 12.9 2.717  0.363  4.1 3.38.  Carbon Dioxide Liquid -Measuring Devices   Handbook 44 –  20152016  
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 Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
− 13.25  243.00  228.31  8.801  8 - 12.8 2.729  0.365  4.1 
− 13.00  244.09  229.39  8.796  8 - 12.7 2.742  0.367  4.2 
− 12.75  245.18  230.49  8.791  8 - 12.7 2.755  0.368  4.2 
− 12.50  246.28  231.58  8.786  8 - 12.6 2.767  0.370  4.2 
− 12.25  247.37  232.68  8.781  8 - 12.5 2.780  0.372  4.2 
− 12.00  248.48  233.78  8.776  8 - 12.4 2.793  0.373  4.3 
− 11.75  249.58  234.89  8.771  8 - 12.3 2.806  0.375  4.3 
− 11.50  250.69  236.00  8.765  8 - 12.2 2.819  0.377  4.3 
− 11.25  251.80  237.11  8.760  8 - 12.2 2.832  0.379  4.3 
− 11.00  252.92  238.22  8.755  8 - 12.1 2.845  0.380  4.3 
− 10.75  254.04  239.34  8.750  8 - 12.0 2.858  0.382  4.4 
− 10.50  255.16  240.47  8.745  8 - 11.9 2.871  0.384  4.4 
− 10.25  256.29  241.60  8.740  8 - 11.8 2.884  0.386  4.4 
− 10.00  257.42  242.73  8.735  8 - 11.8 2.897  0.387  4.4 
− 9.75 258.56  243.86  8.730  8 - 11.7 2.911  0.389  4.5 
− 9.50 259.70  245.00  8.725  8 - 11.6 2.924  0.391  4.5 
− 9.25 260.84  246.14  8.719  8 - 11.5 2.937  0.393  4.5 
− 9.00 261.98  247.29  8.714  8 - 11.4 2.951  0.394  4.5 
− 8.75 263.13  248.44  8.709  8 - 11.3 2.964  0.396  4.5 
− 8.50 264.29  249.59  8.704  8 - 11.3 2.978  0.398  4.6 
− 8.25 265.44  250.75  8.699  8 - 11.2 2.991  0.400  4.6 
− 8.00 266.60  251.91  8.694  8 - 11.1 3.005  0.402  4.6 
− 7.75 267.77  253.07  8.688  8 - 11.0 3.019  0.404  4.6 
− 7.50 268.93  254.24  8.683  8 - 10.9 3.032  0.405  4.7 
− 7.25 270.11  255.41  8.678  8 - 10.8 3.046  0.407  4.7 
− 7.00 271.28  256.59  8.673  8 - 10.8 3.060  0.409  4.7 
− 6.75 272.46  257.76  8.668  8 - 10.7 3.074  0.411  4.7 
− 6.50 273.64  258.95  8.662  8 - 10.6 3.088  0.413  4.8 
− 6.25 274.83  260.13  8.657  8 - 10.5 3.102  0.415  4.8 
− 6.00 276.02  261.32  8.652  8 - 10.4 3.116  0.417  4.8 
− 5.75 277.21  262.52  8.647  8 - 10.3 3.130  0.418  4.8 
− 5.50 278.41  263.72  8.641  8 - 10.3 3.144  0.420  4.9 
− 5.25 279.61  264.92  8.636  8 - 10.2 3.159  0.422  4.9 
− 5.00 280.82  266.12  8.631  8 - 10.1 3.173  0.424  4.9 
− 4.75 282.03  267.33  8.626  8 - 10.0 3.187  0.426  4.9 Handbook 44 –  20152016   3.38.  Carbon Dioxide Liquid -Measuring Devices  
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 Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
− 4.50 283.24  268.55  8.620  8 - 9.9 3.202  0.428  5.0 
− 4.25 284.46  269.76  8.615  8 - 9.8 3.216  0.430  5.0 
− 4.00 285.68  270.98  8.610  8 - 9.8 3.231  0.432  5.0 
− 3.75 286.90  272.21  8.604  8 - 9.7 3.245  0.434  5.0 
− 3.50 288.13  273.44  8.599  8 - 9.6 3.260  0.436  5.1 
− 3.25 289.37  274.67  8.594  8 - 9.5 3.275  0.438  5.1 
− 3.00 290.60  275.91  8.589  8 - 9.4 3.289  0.440  5.1 
− 2.75 291.84  277.15  8.583  8 - 9.3 3.304  0.442  5.1 
− 2.50 293.09  278.39  8.578  8 - 9.2 3.319  0.444  5.2 
− 2.25 294.33  279.64  8.573  8 - 9.2 3.334  0.446  5.2 
− 2.00 295.58  280.89  8.567  8 - 9.1 3.349  0.448  5.2 
− 1.75 296.84  282.14  8.562  8 - 9.0 3.364  0.450  5.3 
− 1.50 298.10  283.40  8.556  8 - 8.9 3.379  0.452  5.3 
− 1.25 299.36  284.67  8.551  8 - 8.8 3.395  0.454  5.3 
− 1.00 300.63  285.93  8.546  8 - 8.7 3.410  0.456  5.3 
− 0.75 301.90  287.21  8.540  8 - 8.6 3.425  0.458  5.4 
− 0.50 303.18  288.48  8.535  8 - 8.6 3.440  0.460  5.4 
− 0.25 304.46  289.76  8.530  8 - 8.5 3.456  0.462  5.4 
0.00 305.74  291.74  8.524  8 - 8.4 3.471  0.464  5.4 
0.25 307.03  292.33  8.519  8 - 8.3 3.487  0.466  5.5 
0.50 308.32  293.62  8.513  8 - 8.2 3.503  0.468  5.5 
0.75 309.61  294.92  8.508  8 - 8.1 3.518  0.470  5.5 
1.00 310.91  296.21  8.502  8 - 8.0 3.534  0.472  5.6 
1.25 312.21  297.52  8.497  8 - 8.0 3.550  0.475  5.6 
1.50 313.52  298.82  8.491  8 - 7.9 3.566  0.477  5.6 
1.75 314.83  300.13  8.486  8 - 7.8 3.582  0.479  5.6 
2.00 316.15  301.45  8.480  8 - 7.7 3.598  0.481  5.7 
2.25 317.46  302.77  8.475  8 - 7.6 3.614  0.483  5.7 
2.50 318.79  304.09  8.469  8 - 7.5 3.630  0.485  5.7 
2.75 320.11  305.42  8.464  8 - 7.4 3.646  0.487  5.8 
3.00 321.45  306.75  8.458  8 - 7.3 3.662  0.490  5.8 
3.25 322.78  308.08  8.453  8 - 7.2 3.679  0.492  5.8 
3.50 324.12  309.42  8.447  8 - 7.2 3.695  0.494  5.8 
3.75 325.46  310.77  8.442  8 - 7.1 3.712  0.496  5.9 
4.00 326.81  312.11  8.436  8 - 7.0 3.728  0.498  5.9 3.38.  Carbon Dioxide Liquid -Measuring Devices   Handbook 44 –  20152016  
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Agency No. 209.02  
 Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
4.25 328.16  313.46  8.431  8 - 6.9 3.745  0.501  5.9 
4.50 329.52  314.82  8.425  8 - 6.8 3.761  0.503  6.0 
4.75 330.88  316.18  8.420  8 - 6.7 3.778  0.505  6.0 
5.00 332.24  317.54  8.414  8 - 6.6 3.795  0.507  6.0 
5.25 333.61  318.91  8.408  8 - 6.5 3.812  0.510  6.1 
5.50 334.98  320.28  8.403  8 - 6.4 3.829  0.512  6.1 
5.75 336.35  321.66  8.397  8 - 6.4 3.846  0.514  6.1 
6.00 337.73  323.04  8.392  8 - 6.3 3.863  0.516  6.2 
6.25 339.12  324.42  8.386  8 - 6.2 3.880  0.519  6.2 
6.50 340.51  325.81  8.380  8 - 6.1 3.897  0.521  6.2 
6.75 341.90  327.20  8.375  8 - 6.0 3.915  0.523  6.3 
7.00 343.30  328.60  8.369  8 - 5.9 3.932  0.526  6.3 
7.25 344.70  330.00  8.363  8 - 5.8 3.949  0.528  6.3 
7.50 346.10  331.41  8.358  8 - 5.7 3.967  0.530  6.3 
7.75 347.51  332.82  8.352  8 - 5.6 3.984  0.533  6.4 
8.00 348.92  334.23  8.346  8 - 5.5 4.002  0.535  6.4 
8.25 350.34  335.65  8.341  8 - 5.4 4.020  0.537  6.4 
8.50 351.76  337.07  8.335  8 - 5.4 4.038  0.540  6.5 
8.75 353.19  338.49  8.335  8 - 5.4 4.038  0.540  6.5 
9.00 354.62  339.92  8.323  8 - 5.2 4.073  0.545  6.5 
9.25 356.06  341.36  8.318  8 - 5.1 4.091  0.547  6.6 
9.50 357.49  342.80  8.312  8 - 5.0 4.110  0.549  6.6 
9.75 358.94  344.24  8.306  8 - 4.9 4.128  0.552  6.6 
10.00  360.38  345.69  8.300  8 - 4.8 4.146  0.554  6.7 
10.25  361.84  347.14  8.295  8 - 4.7 4.164  0.557  6.7 
10.50  363.29  348.60  8.289  8 - 4.6 4.183  0.559  6.7 
10.75  364.75  350.06  8.283  8 - 4.5 4.201  0.562  6.8 
11.00  366.22  351.52  8.277  8 - 4.4 4.220  0.564  6.8 
11.25  367.68  352.99  8.271  8 - 4.3 4.238  0.567  6.8 
11.50  369.16  354.46  8.266  8 - 4.2 4.257  0.569  6.9 
11.75  370.64  355.94  8.260  8 - 4.2 4.276  0.572  6.9 
12.00  372.12  357.42  8.254  8 - 4.1 4.295  0.574  7.0 
12.25  373.60  358.91  8.248  8 - 4.0 4.314  0.577  7.0 
12.50  375.09  360.40  8.242  8 - 3.9 4.333  0.579  7.0 
12.75  376.59  361.89  8.236  8 - 3.8 4.352  0.582  7.1 Handbook 44 –  20152016   3.38.  Carbon Dioxide Liquid -Measuring Devices  
  Markup Copy 
  Agency No. 209.02  
 
 Table N.4.4.  
Automatic Temperature or Density C ompensation  
Temp  °F Pressure  Liquid Density  Vapor Density  Vapor 
Displacement  % PSIA  PSIG  lb/gal  (lb-oz)/gal  lb/cu ft  lb/gal  
13.00  378.09  363.39  8.230  8 - 3.7 4.371  0.584  7.1 
13.25  379.59  364.89  8.224  8 - 3.6 4.390  0.587  7.1 
13.50  381.10  366.40  8.219  8 - 3.5 4.410  0.589  7.2 
13.75  382.61  367.91  8.213  8 - 3.4 4.429  0.592  7.2 
14.00  384.13  369.43  8.207  8 - 3.3 4.449  0.595  7.2 
14.25  385.65  370.95  8.201  8 - 3.2 4.468  0.597  7.3 
14.50  387.17  372.48  8.195  8 - 3.1 4.488  0.600  7.3 
14.75  388.70  374.01  8.189  8 - 3.0 4.508  0.603  7.4 
15.00  390.24  375.54  8.183  8 - 2.9 4.527  0.605  7.4 
15.25  391.78  377.08  8.177  8 - 2.8 4.547  0.608  7.4 
15.50  393.32  378.62  8.171  8 - 2.7 4.567  0.611  7.5 
15.75  394.87  380.17  8.165  8 - 2.6 4.587  0.613  7.5 
16.00  396.42  381.72  8.159  8 - 2.5 4.608  0.616  7.5 
16.25  397.98  383.28  8.153  8 - 2.4 4.628  0.619  7.6 
16.50  399.54  384.84  8.147  8 - 2.3 4.648  0.621  7.6 
16.75  401.10  386.41  8.141  8 - 2.2 4.669  0.624  7.7 
17.00  402.67  387.98  8.134 8 - 2.2 4.689  0.627  7.7 
17.25  404.25  389.55  8.128  8 - 2.1 4.710  0.630  7.7 
17.50  405.82  391.13  8.122  8 - 2.0 4.731  0.632  7.8 
17.75  407.41  392.71  8.116  8 - 1.9 4.751  0.635  7.8 
18.00  409.00  394.30  8.110  8 - 1.8 4.772  0.638  7.9 
18.25  410.59  395.89  8.104  8 - 1.7 4.793  0.641  7.9 
18.50  412.19  397.49  8.098  8 - 1.6 4.814  0.644  7.9 
18.75  413.79  399.09  8.092  8 - 1.5 4.835  0.646  8.0 
19.00  415.39  400.70  8.085  8 - 1.4 4.857  0.649  8.0 
19.25  417.00  402.31  8.079  8 - 1.3 4.878  0.652  8.1 
19.50  418.62  403.92  8.073  8 - 1.2 4.900  0.655  8.1 
19.75  420.24  405.54  8.067  8 - 1.1 4.921  0.658  8.2 
20.00  421.86  407.17  8.061  8 - 1.0 4.943  0.661  8.2 3.38.  Carbon Dioxide Liquid -Measuring Devices   Handbook 44 –  20152016  
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T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Underregistration and to Overregistration. – The tolerances hereinafter prescribed shall be 
applied to errors of underregistration and errors of overregistration.  
 
T.2. Tolerance Values. –  The maintenance and acceptance tolerances for normal and special tests shall be as 
shown in Table  T.2. Accuracy Classes and Tolerances for Carbon Dioxide Liquid -Measuring Devices.  
 
Table T.2.  
Accuracy Classes and Tolerances for Carbon Dioxide Liquid -Measuring Devices  
Accuracy 
Class  Application  Acceptance 
Tolerance Maintenance 
Tolerance Special Test 
Tolerance 
2.5 Liquid carbon dioxide  1.5 % 2.5 % 2.5 % 
(Table Added 2003) (Amended 2003)  
 
T.2.1.  Repeatability.  – When multiple tests are conducted at approximately the same flow rate and draft 
size, the range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance 
tolerance and the results of each test shall be within the  applicable tolerance. (Also see N.4.1.1 . Repeatability 
Tests.)  
(Added 2002)  
 
T.3. On Tests Using Transfer Standards. –  To the basic tolerance values that would otherwise be applied, there 
shall be added an amount equal to two times the standard deviation of the applicable transfer standard when 
compared to a basic reference standard.  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Discharge Rate. –  A device shall be so installed that the actual maximum discharge rate will not 
exceed the rated maximum discharge rate.  If necessary, means for flow regulation shall be incorporated in the 
installation.  
 
UR.1.2.  Length of Discharge Hose. –  The discharge hose shall be of such a length and design as to keep 
vaporization of the liquid to a minimum.  
 
UR.1.3.  Maintenance of Liquid State. –  A device shall be so installed and operated that the product being 
measured shall remain in the liquid state during passag e through the meter.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Return of Indicating and Recording Elements to Zero. –  The primary indicating elements (visual) 
and the primary recording elements shall be returned to zero immediately before each delivery.  
 
UR.2.2.  Condition of Discharge System. –  The discharge hose, up to the valve at the end of the discharge 
hose, shall be completely filled and pre- cooled to liquid temperatures before a “zero” condition is established Handbook 44 –  20152016   3.38.  Carbon Dioxide Liquid -Measuring Devices  
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  Agency No. 209.02  
 
 and prior to the start of a commercial delivery.   Means shall be provided to fill the discharge hose with liquid 
prior to the start of a delivery.  
 
UR.2.3.  Vapor Equalization Line. –  A vapor equalization line shall not be used during a metered delivery 
unless the quantity of vapor displaced from the buyer’s tank to the seller’s tank is deducted from the metered 
quantity.  The appropriate correction values shall apply as specified in Table N.4.4.  
 
UR.2.4.  Temperature or Density Compensation.  
 
UR.2.4.1.  Use of Automatic Temperature or Density Compensators. –  Devices equipped with an 
automatic temperature or density compensator shall have the compensator connected, operable, and in use 
at all times.  Such automatic temperature or density compensator may no t be removed.  
 UR.2.4.2.  Tickets or Invoices. –  Any written invoice or printed ticket based on a reading of a 
device that is equipped with an automatic temperature or density compensator shall have shown thereon 
that the quantity delivered has been temperature or density compensated.  
 
UR.2.5.  Ticket in Printing Device. –  A ticket shall not be inserted into a device equipped with a ticket 
printer until immediately before a delivery is begun, and in no case shall a ticket be in the device when the vehicle is in motion while on a public street, highway, or thoroughfare.  
 
UR.2.6.  Sale by Weight. –  All quantity determinations shall be made by means of an approved and sealed 
weighing or measuring device.  All sales shall be stated in kilograms or pounds.  
  3.38.  Carbon Dioxide Liquid -Measuring Devices   Handbook 44 –  20152016  
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 Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
  Markup Copy 
  Agency No. 209.02  
 Section 3.39.  Hydrogen Gas-Measuring Devices – Tentative Code  
 
This tentative code has  only a trial or experimental status and is not intended to be enforced.  The requirements are 
designed for study prior to the development and adoption of a final code .  Requirements  that apply to wholesale 
applications are under study and development by  the U. S. National Work Group for the Development of 
Commercial Hydrogen Measurement Standards.  Officials wanting to conduct an official examination of a device or 
system are advised to see paragraph G -A.3. Special and Unclassified Equipment.  
(Tentative Code Add ed 2010)  
A. Application  
A.1. General.  – This code applies to devices that are used for the measurement of hydrogen gas in the vapor state 
used as a vehicle fuel.  
 
A.2. Exceptions.  – This code does not apply to:  
 
(a) Devices used solely for dispensing a product  in connection with operations in which the amount dispensed 
does not affect customer charges.  
 
(b) The wholesale delivery of hydrogen gas.  
 
(c) Devices used for dispensing a hydrogen gas with a hydrogen fuel index lower than 99.97 % and 
concentrations of specified impurities that exceed level limits.  
 (d) Systems that measure pressure, volume, and temperature with a calculating device to determine the mass of 
gas accumulated in or discharged from a tank of known volume.  
 
A.3. Additional Code Requirements. –  In additio n to the requirements of this code, Hydrogen Gas -Measuring 
Devices shall meet the requirements of Section 1.10. General Code.  
 A.4. Type Evaluation. –  The National Type Evaluation Program (NTEP) will accept for type evaluation only 
those devices that comply with all requirements of this code.  
 
S. Specifications  
 
S.1. Indicating and Recording Elements.  
 
S.1.1.  Indicating Elements . – A measuring assembly shall include an indicating element that 
continuously displays measurement results relative to quantity  and total price. Indications shall be clear, definite, 
accurate, and easily read under normal conditions of operation of the device.  
 
S.1.2.  Vehicle Fuel Dispensers . – A hydrogen gas dispenser used to fuel vehicles shall be of the 
computing type a nd shall indicate the mass, the unit price, and the total price of each delivery.  
 
S.1.3.  Units.  
 
S.1.3.1.  Units of Measurement.  – Deliveries shall be indicated and recorded in kilograms and decimal 
subdivisions thereof.  
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 S.1.3.2.  Numerical Value of Quantity -Value Divisions. –  The value of an interval (i.e., increment or 
scale division) shall be equal to:  
(a) 1, 2, or 5; or  
 (b) a decimal multiple or submultiple of 1, 2, or 5.  
 
Examples:  quantity- value divisions may be 10, 20, 50,  100; or 0.01, 0.02, 0.05; or 0.1, 0.2, or 0.5 
etc. 
 
S.1.3.3.  Maximum Value of Quantity- Value Divisions. –  The maximum value of the quantity- value 
division shall not be greater than 0.5% of the minimum measured quantity.  
 
S.1.3.4.  Values Defined.  – Indicat ed values shall be adequately defined by a sufficient number of 
figures, words, symbols, or combinations thereof. A display of “zero” shall be a zero digit for all displayed 
digits to the right of the decimal mark and at least one to the left.  
 
S.1.4.  Value of Smallest Unit . – The value of the smallest unit of indicated delivery, and recorded 
delivery if the device is equipped to record, shall not exceed the equivalent of:  
 
(a) 0.001 kg on devices with a marked maximum flow rated of 30 kg/min or less; or  
(b) 0.01 kg on devices with a marked maximum flow rate of more than 30 kg/min.  
S.2. Operating Requirements.  
 
S.2.1.  Return to Zero.  
 
(a) The primary indicating and the primary recording elements, if the device is equipped to record, shall be 
provided with a means for readily returning the indication to zero either automatically or manually.  
 
(b) It shall not be possible to return primary indicating elements, or primary recording elements, beyond 
the correct zero position.  
 
S.2.2.  Indicator Reset Mechanism.  – The reset mechanism for the indicating element shall not be 
operable during a delivery. Once the zeroing operation has begun, it shall not be possible to indicate a value 
other than the latest measurement, or “zeros” when the zeroing operation has been completed.  
 
S.2.3.  Provision for Power Loss.  
 
S.2.3.1.  Transaction Information.  – In the event of a power loss, the information needed to complete 
any transaction in progress at the time of the power loss (such as the quantity and unit price, or sales pri ce) 
shall be determinable for at least 15 minutes at the dispenser or at the console if the console is accessible to 
the customer.  
 
S.2.3.2.  User Information.  – The device memory shall retain information on the quantity of fuel 
dispensed and the sales price totals during power loss.  
 
S.2.4.  Display of Unit Price and Product Identity.  
 
S.2.4.1.  Unit Price . – A computing or money- operated device shall be able to display on each face the 
unit price at which the device is set to compute or to dispense.  
 
S.2.4.2.  Product Identity.  – A device shall be able to conspicuously display on each side the identity of 
the product being dispensed.  Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
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 S.2.4.3.  Selection of Unit Price.  – When a product is offered for sale at more than on unit price through 
a computing device, the selection of the unit price shall be made prior to delivery using controls on the 
device or other customer -activated controls. A system shall not permit a change to the unit price during 
delivery of a product.  
 
S.2.4.4.  Agreement Between Indications.  – All quantity , unit price, and total price indications within a 
measuring system shall agree for each transaction.  
 
S.2.5.  Money -Value  Computations. – A comp uting device shall compute the total sales price at any 
single -purchase unit price for which the product being measured is offered for sale at any delivery possible 
within either the measurement range of the device or the range of the computing elements, w hichever is less.  
 
S.2.5.1.  Auxiliary Elements.  – If a system is equipped with auxiliary indications, all indicated money 
value and quantity divisions of the auxiliary element shall be identical with those of the primary element.  
 
S.2.5.2.  Display of Quantity and Total Price.  – When a delivery is completed, the total price and 
quantity for that transaction shall be displayed on the face of the dispenser for at least 5 minutes or until the 
next transaction is initiated by using controls  on the device or  other user -activated controls.  
 
S.2.6.  Recorded Representations, Point of Sale Systems. –  A printed receipt shall be available through 
a built -in or separate recording element for transactions conducted with point -of-sale systems or devices 
activated by debit cards, credit cards, and/or cash. The printed receipt shall contain the following information 
for products delivered by the dispenser:  
 
(a) the total mass of the delivery;  
 
(b) the unit price;  
 
(c) the total computed price; and  
 
(d) the product identity  by name, symbol, abbreviation, or code number.  
 
S.2.7.  Indication of Delivery. –  The device shall automatically show on its face the initial zero 
condition and the quantity delivered (up to the nominal capacity).  
 
S.3. Design of Measuring Elements and Mea suring Systems.  
 
S.3.1.  Maximum and Minimum Flow -Rates.  – The ratio of the maximum to minimum flow -rates 
specified by the manufacturer for devices measuring gases shall be 10:1 or greater.  
 
S.3.2.  Adjustment  Means.  – An assembly shall be provided with means  to change the ratio between the 
indicated quantity and the quantity of gas measured by the assembly.  A bypass on the measuring assembly shall not be used for these means.  
 
 S.3.2.1. Discontinuous Adjusting Means.  – When the adjusting means changes  ratio between the 
indicated quantity and the quantity of measured gas  in a discontinuous manner, the consecutive values of 
the ratio shall not differ by more than 0.1 %.  
 
S.3.3.  Provision for Sealing.  – Adequate provision shall be made for an approved me ans of security 
(e.g., data change audit trail) or physically applying security seals in such a manner that no adjustment may be made of:  
 
(a) each individual measurement element;  
 
(b) any adjustable element for controlling delivery rate when such rate ten ds to affect the accuracy of 
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(c) the zero adjustment mechanism; and  
 
(d) any metrological parameter that detrimentally affects the metrological integrity of the device or 
system.  
When applicable, the adjusting mechanism shall be readily access ible for purposes of affixing a security seal. Audit 
trails shall use the format set forth in Table S.3.3. Categories of Device and Methods of Sealing.  
 
Table S.3.3.  
Categories of Device and Methods of Sealing  
Categories of Device  Method of Sealing  
Category 1:   No remote configuration capability.  Seal by physical seal or two event counters: one for 
calibration parameters and one for  configuration 
parameters.  
Category 2:   Remote configuration capability, but 
access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode or shall not operate while in this  mode.  The hardware enabling access for remote 
communication must be on -site.  The hardware must be 
sealed using a physical seal or an event counter for 
calibration parameters and an event counter for 
configuration parameters.  The event counters may be 
located either at the individual measuring device or at  
the system controller; however, an adequate number of 
counters must be provided to monitor the calibration 
and configuration parameters of the individual devices 
at a location.  If the counters are located in the system 
controller rather than at the individual device, means 
must be provided to generate a hard copy of the 
information through an on- site device.  
Category 3:   Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password). 
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode or shall not operate while in this mode.  An event logger is required in the device; it must 
include an event counter (000 to 999), the parameter 
ID, the date and time of the change, and the new value 
of the parameter.  A printed copy of the information 
must  be available through the device or through 
another on- site device.  The event logger shall have a 
capacity to retain records equal to 10 times the number 
of sealable parameters in the device, but not more than 
1000 records are required.  (Note:   Does not require 
1000 changes to be stored for each parameter.)  
 
S.3.4.  Automatic Density Correction.  
 
(a) An automatic means to determine and correct for changes in product density shall be incorporated in 
any hydrogen gas -measuring system where measurements are affected by changes in the density of the 
product being measured.  
 
(b) Volume -measuring devices with automatic temperature compensation used to measure hydrogen gas 
as a vehicle fuel shall be equipped with an automatic means to determine and correct for changes in product density due to changes in the temperature, pressure, and composition of the product.  
 
S.3.5.  Pressurizing the Discharge Hose.  – The discharge hose for hydrogen gas shall automatically 
pressurize to a pressure equal to or greater than the receiving vessel prior to the device beginning to register the 
delivery.  The indications shall not advance as a result of the initial pressurization or the purging/bleeding of the discharge hose.  Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
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S.3.6.  Zero -Set-Back Interlock, Retail Vehicle Fuel Devices.  
 
(a) A device shall be constructed so that:  
 
(1) when  the device is shut -off at the end of a delivery an automatic interlock prevents a subsequent 
delivery until the indicating element and recording elements, if the device is equipped and ac -
tivated  to record, have been returned to their zero positions; and  
 
(2) it shall not be possible to return the discharge nozzle to its start position unless the zero set back 
interlock is engaged or becomes engaged.  
 
(b) For systems with more than one:  
 
(1) dispenser  supplied by a single measuring element, an effective automatic control valve in each 
dispenser prevents product from being delivered until the indicating elements on that dispenser are 
in a correct zero position; or  
 
(2) hose supplied by a single measuring eleme nt, effective automatic means must be provided to 
prevent product from being delivered until the indicating element(s) corresponding to each hose 
are in a correct zero position.  
 
S.4. Discharge Lines and Valves.  
 
S.4.1.  Diversion of Measured Product.  – No means shall be provided by which any measured product 
can be diverted from the measuring device.   
 S.4.2.  Directional Flow Valves.  – If a reversal of flow could result in errors that exceed the tolerance for 
the minimum measured quantity, a valve or  valves or other effective means, automatic in operation (and 
equipped with a pressure limiting device, if necessary) to prevent the reversal of flow shall be properly installed in the system. (Also see N.1. Minimum Measured Quantity.)  
 
S.4.3.  Other Valves . – Check valves and closing mechanisms that are not used to define the measured 
quantity shall have relief valves (if necessary) to dissipate any abnormally high pressure that may arise in the 
measuring assembly.  
 
S.5. Markings.  – A measuring system shall  be conspicuously, legibly, and indelibly marked with the following 
information:  
 
(a) pattern  approval mark (i.e., type approval number);  
 
(b) name  and address of the manufacturer or his trademark and, if required by the weights and measures 
authority, the manufac turer's identification mark in addition to the trademark;  
 
(c) model  designation or product name selected by the manufacturer;  
 
(d) nonrepetitive  serial number;  
 (e) the accuracy class of the device as specified by the manufacturer consistent with Table T.2. Accuracy 
Classes and Tolerances for Hydrogen -Gas Measuring Devices;  
 (f) maximum and minimum flow rates in kilograms per unit of time;  
 (g) maximum working pressure;  
 
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(i) minimum measured quantity; and  
 
(j) product  limitations (such as fuel quality), if applicable.  
 
S.5.1.  Location of Marking Information; Hydrogen -Fuel Dispensers.  – The ma rking information 
required in General Code, paragraph G S.1. Identification  shall appear as follows:  
 
(a) within  60 cm (24 in) to 150 cm (60 in) from the base of the dispenser;  
 (b) either  internally and/or externally provided the information is permanent and easily read; and 
accessible for inspection; and  
 
(c) on a portion of the device that cannot be readily removed or interchanged (i.e., not on a service access 
panel).  
 
Note:   The use of a dispenser key or tool to access internal marking information is permitted for retail hydrogen- measuring 
devices.  
 
S.6. Printer.  – When an assembly is equipped with means for printing the measured quantity, the printed 
information must agree with the indications on the dispenser for the transaction and the printed values shall be 
clearly defined.  
 
S.6.1.  Printed Receipt.  – Any delivered, printed quantity shall include an identification number, the 
time and date, and the name of the seller.  Th is information may be printed by the device or pre -printed on the 
ticket.  
 
S.7. Totalizers  for Vehicle Fuel Dispensers.  – Vehicle fuel dispensers shall be equipped with a nonresettable  
totalizer  for the quantity delivered through each separate measuring de vice.  
 
S.8. Minimum Measured Quantity.  – The minimum measured quantity shall satisfy the conditions of use of the 
measuring system as follows:  
 
(a) Measuring systems having a maximum flow rate less than or equal to 4  kg/min shall have a minimum 
measured quanti ty not exceeding 0.5 kg.  
 
(b) Measuring systems having a maximum flow rate greater than 4 kg/min but not greater than 12  kg/min shall 
have a minimum measured quantity not exceeding 1.0  kg. 
N. Notes  
N.1. Minimum Measured Quantity.  – The minimum measured quantity shall be specified by the manufacturer.  
 
N.2. Test Medium.  – The device shall be tested with the product commercially measured except that, in a type 
evaluation examination, hydrogen gas as specified in NIST Handbook 130 sh all be used.  
 Note:   Corresponding requirements are under development and this paragraph will be revisited.  
 
N.3. Test Drafts.  – The minimum test shall be one test draft at the declared minimum measured quantity and one 
test draft at approximately ten time s the minimum measured quantity or 1 kg, whichever is greater.  More tests may 
be performed over the range of normal quantities dispensed.  (Also s ee T.3. Repeatability. ) 
 
The test draft shall be made at  flows representative of that during normal delivery.   The pressure drop between the 
dispenser and the proving system shall not be greater than that for normal deliveries.  The control of the flow (e.g., Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
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 pipework or valve(s) size, etc.) shall be such that the flow of the measuring system is maintained within  the range 
specified by the manufacturer.  
 
N.4. Tests.  
 
N.4.1.  Master Meter (Transfer) Standard Test.  – When comparing a measuring system with a 
calibrated transfer standard, the minimum test shall be one test draft at the declared minimum measured 
quantit y and one test draft at approximately ten times the minimum measured quantity or 1 kg, whichever is 
greater.  More tests may be performed over the range of normal quantities dispensed.  
 
N.4.1.1.  Verification of Master Metering Systems. – A master metering system used to verify a 
hydrogen gas -measuring device shall be verified before and after the verification process.  A master 
metering system used to calibrate a hydrogen gas -measuring device shall be verified before starting the 
calibration and after the calibration process.  
 
N.4.2.  Gravimetric Tests.  – The weight of the test drafts shall be equal to at least the amount delivered 
by the device at the declared minimum measured quantity and one test draft at approximately ten times the 
minimum measured quanti ty or 1 kg, whichever is greater.  More tests may be performed over the range of 
normal quantities dispensed.    N.4.3.  PVT Pressure Volume Temperature Test.  – The minimum test with a calibrated volumetric  
standard shall be one test draft at the declared m inimum measured quantity  and one test draft at approximately 
ten times the minimum measured quantity or 1 kg, whichever is greater.  More tests may be performed over the range of normal quantities dispensed.  
 
N.5. Minimum Measured Quantity.  – The device sh all be tested for a delivery equal to the declared minimum 
measured quantity when the device is likely to be used to make deliveries on the order of the declared minimum measured quantity.  
 
N.6. Testing Procedures.  
 
N.6.1.  General.  – The device or system s hall be tested under normal operating conditions of the 
dispenser.  
 
The test draft shall be made at  flows representative of that during normal delivery.  The pressure drop between 
the dispenser and the proving system shall not be greater than that for norm al deliveries.  The control of the 
flow (e.g., pipework or valve(s) size, etc.) shall be such that the flow of the measuring system is maintained 
within the range specified by the manufacturer.  
 
N.6.1.1.  Repeatability  Tests. – Tests for repeatability  shoul d include a minimum of three consecutive 
test drafts of approximately the same size and be conducted under controlled conditions where variations in 
factors are reduced to minimize the effect on the results obtained.  
 
N.7. Density.  – Temperature and pressure of hydrogen gas shall be measured during the test for the determination 
of density or volume correction factors when applicable.  For the thermophysical properties of hydrogen the 
following publications shall apply:  for density  calculations at temperatures above 255 K and pressures up to 120 
MPa, a simple relationship may be used that is given in the publication of Lemmon et al., J. Res. NIST, 2008.  
Calculations for a wider range of conditions and additional thermophysical properties of hydrogen are available free 
of charge online at the “NIST Chemistry WebBook” http://webbook.nist.gov/chemistry , or available for purchase 
from NIST as the computer program NIST Standard Reference Database 23 “NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP): Version 8.0” http://www.nist.gov/srd/nist23.cfm .  
These calculations are based on the reference Leachman, J.W., Jacobsen, R.T, Lemmon, E.W., and Penoncello, S.G. 
“Fundamental Equations of State for Parahydrogen, Normal Hydrogen, and Orthohydrogen" to be published in the 
Journal of Physical and Chemical Reference Data ( http://www.nist.gov/manuscript -publication-
search.cfm?pub_id=832374).   More information may be obtained from NIST online at 
http://www.boulder.nist.go v/div838/Hydrogen/Index.htm . 3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  Handbook 44 –  20152016  
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T. Tolerances  
T.1. Tolerances, General.  
 
(a) The tolerances apply equally to errors of underregistration and errors of overregistration . 
 
(b) The tolerances apply to all products at all temperatures measured at any flow rate within the rated 
measuring range of the device.  
 
T.2. Tolerances.  – The tolerances for hydrogen gas measuring devices are listed in Table T.2. Accuracy Classes 
and Tolerances for Hydrogen Gas -Measuring Devices.  ( Proposed tolerance values are based on previous w ork with 
compressed gas products and will be confirmed based on performance data evaluated by the U.S. National Work 
Group.)  
 
Table T.2.  
Accuracy Classes and Tolerances for Hydrogen Gas -Measuring Devices  
Accuracy Class  Application or Commodity Being 
Measured  Acceptance 
Tolerance Maintenance 
Tolerance 
2.0 Hydrogen gas as a vehicle fuel  1.5 % 2.0 % 
 
T.3. Repeatability . – When multiple tests are conducted at approximately the same flow rate and draft size, the 
range of the test results for the flow rate shall not exceed 40  % of the absolute value of the maintenance tolerance 
and the results of each test shall be within th e applicable tolerance.  (Also see N.6.1.1. Repeatability  Tests.)  
 
T.4. Tolerance Application on Test Using Transfer Standard Test Method.  – To the basic tolerance values 
that would otherwise be applied, there shall be added an amount equal to two times th e standard deviation of the 
applicable transfer standard when compared to a basic reference standard.  
 T.5. Tolerance Application in Type Evaluation Examinations for Devices.  – For type evaluation examinations, 
the tolerance values shall apply under the fo llowing conditions:  
 
(a) at any temperature and pressure within the operating range of the device, and  
 
(b) for all quantities greater than the minimum measured quantity.  
UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1.  Computing -Type Device; Retail Dispenser.  – A hydrogen gas dispenser used to refuel vehicles 
shall be of the computing type and shall indicate the mass, the unit price, and the total price of each delivery.  
 
UR.1.2.  Discharge Hose- Length.  – The length of the discharge hose on a retail f uel dispenser:  Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
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(a) shall  not exceed 4.6  m (15  ft) unless it can be demonstrated that a longer hose is essential to permit 
deliveries to be made to receiving vehicles or vessels;  
 
(b) shall  be measured from its housing or outlet of the discharge line to the inlet of the discharge nozzle; 
and 
 
(c) shall  be measured with the hose fully extended if it is coiled  or otherwise retained or connected inside 
a housing.  
 An unnecessarily remote location o f a device shall not be accepted as justification for an abnormally long hose.  
 
UR.1.3.  Minimum Measured Quantity.  
 
(a) The minimum measured quantity shall be specified by the manufacturer.   
 
(b) The minimum measured quantity appropriate for a transaction  may be specified by the weights and 
measures authority.  A device may have a declared minimum measured quantity smaller than that specified by the weights and measures authority; however, the device must perform within the 
performance requirements for the  declared or specified minimum measured quantity up to  deliveries at 
the maximum measurement range.  
 
(c) The minimum measured quantity shall satisfy the conditions of use of the measuring system as 
follows:  
 
(1) measuring  systems having a maximum flow rate less than or equal to 4  kg/min shall have a 
minimum measured quantity not exceeding 0.5  kg; and  
 
(2)  measuring  systems having a maximum flow rate greater than 4 kg/min but not greater than 
12 kg/min shall have a minimum  measured quantity not exceeding 1.0 kg.  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Manufacturer’s Instructions.  – A device shall be installed in accordance with the manufacturer’s 
instructions, and the installation shall be sufficiently secure and rigid to maintain this condition.  
 
UR.2.2.  Discharge Rate.  – A device shall be installed so that after initial equaliza tion the actual maximum 
discharge rate will not exceed the rated maximum discharge rate.  Automatic means of flow regulation shall be 
incorporated in the installation if necessary.  
 
UR.2.3.  Low -Flow Cut-Off Valve.  – If a measuring system is equipped with a  programmable or adjustable 
"low -flow cut-off" feature:  
 
(a) the low-flow cut-off value shall not be set at flow rates lower than the minimum operating flow rate 
specified by the manufacturer on the measuring device; and  
 
(b) the system shall be equipped with flow control valves which prevent the flow of product and stop 
the indicator from registering product flow whenever the product flow rate is less than the low -
flow cut-off value.  
 
UR.3.  Use of Device.  
 
UR.3.1.  Unit Price and Product Identity for Retail Dispensers.  – The unit price at which the dispenser is 
set to compute shall be conspicuously displayed or posted on the face of a retail dispenser used in direct sale.  
 
UR.3.2.  Vehicle -mounted Measuring Systems Ticket Printer.   3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  Handbook 44 –  20152016  
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UR.3.2.1.  Customer Ticket. –  Vehicle -mounted measuring systems shall be equipped with a ticket printer 
which shall be used for all sales where product is delivered through the device.  A copy of the ticket issued 
by the device shall be left with the custo mer at the time of delivery or as otherwise specified by the 
customer.  
 
UR.3.2.2.  Ticket in Printing Device. –  A ticket shall not be inserted into a device equipped with a ticket 
printer until immediately before a delivery is begun, and in no case shall a ticket be in the device when the vehicle is in motion while on a public street, highway, or thoroughfare.  
 
UR.3.3.  Printed Ticket.  – The total price, the total quantity of the delivery, and the price per unit shall be 
printed on any ticket issued by a device of the computing type and containing any one of these values.  
 
UR.3.4.  Steps After Dispensing.  – After delivery to a customer f rom a retail dispenser:  
 
(a) the device shall be shut -off at the end of a delivery, through an automatic interlock that prevents a 
subsequent delivery until the indicating elements and recording elements, if the device is equipped and 
activated to record, have been returned to their zero positions; and  
 
(b) the discharge nozzle shall not be returned to its start  position unless the zero set- back interlock is 
engaged or becomes engaged by  the act of disconnecting the nozzle or the act of returning the 
discharge nozzle.   
 
UR.3.5.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements 
(visual), and the primary recording elements shall be returned to zero immediately before each delivery.   
 
UR.3.6.  Return of Product to Storage, Retail H ydrogen Gas Dispensers.  – Provisions at the site shall be 
made for returning product to storage  or disposing of the product in a safe and timely manner during or 
following testing operations.  Such provisions may include return lines, or cylinders adequate  in size and 
number to permit this procedure.  
 
UR.3.7.  Conversion Factors.  – Established correction values.  (Also see references in N.7. Density.) shall be 
used whenever measured hydrogen gas is billed.  All sales shall be based on kilograms.  
 
Appendix D.   Definitions  
The specific code to which the definition applies is shown in [brackets] at the end of the definition.  Definitions for 
the General Code [1.10] apply to all codes in Handbook 44.  
 
A 
 
audit  trail.  – An electronic count and/or information  record of the changes to the values of the calibration or 
configuration parameters of a device. [1.10, 2.20, 2.21, 2.24, 3.30, 3.37, 3.39, 5.56( a)]   
 
automatic  temperature or density compensation . – The use of integrated or ancil lary equipment to obtain  from 
the output of a volumetric  meter an equivalent mass, or an equivalent liquid volume at the assigned reference 
temperature below and a pressure of 14.696 lb/in2 absolute.  
 
Cryogenic liquids  21 °C (70  °F) [3.34]  
Hydrocarbon gas vapor  15 °C (60  °F) [3.33]  
Hydrogen gas  21 °C (70 °F) [3.39]  
Liquid carbon dioxide  21 °C (70 ° F) [3.38]  Handbook 44 –  20152016  3.39.  Hydrogen Gas -Measuring Devices –  Tentative Code  
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 Liquefied petroleum gas (LPG) and Anhydrous ammonia  15 °C (60  °F) [3.32]  
Petroleum liquid fuels and lubricants  15 °C (60  °F) [3.30]  
[3.39]  
C 
 
calibration  parameter.  – Any adjustable parameter that can affect measurement or performance accuracy and, due 
to its nature, needs to be updated on an ongoing basis to maintain device accuracy (e.g., span adjustments, 
linearization  factors, and coarse zero adjustments) . [2.20, 2 .21, 2.24, 3.30, 3.37, 3.39, 5.56( a)]   
 
D 
 
discharge  hose.  – A flexible hose connected to the discharge outlet of a measur ing device or its discharge line . 
[3.30, 3.31, 3.32, 3.34, 3.37, 3.38, 3.39]  
 
discharge  line. – A rigid pipe connected to the outlet of a measuring device. [3.30, 3.31, 3.32, 3.34, 3.37, 3.39]  
 
E 
 
event  counter . – A non-resettable counter that increments once each time the mode that permits changes to sealable  
parameters is entered and one or more changes are made to sealable calibration or configuration parameters of a 
device. [2.20, 2.21, 3.30, 3.37, 3.39, 5.54, 5.56 (a), 5.56 (b), 5.57]   
 
event  logger.  – A form of audit trail containing a series of records wh ere each record contains the number from the 
event counter corresponding to the change to a sealable parameter, the identification of the parameter that was 
changed, the time and date when the parameter was changed, and the new value of the parameter . [2.20, 2.21, 3.30, 
3.37, 3.39, 5.54, 5.56( a), 5.56 (b), 5.57]  
 
I 
 
indicating  element.  – An element incorporated in a weighing or measuring device by means of which its 
performance relative to quantity or money  value is "read" from the device itself as, for example, an 
index -and-graduated -scale combination, a weigh beam -and-poise combi nation , a digital indicator, and the like .  
(Also see "primary indicating or recording element." ) [1.10]  
 
M 
 
minimum measured quantity (MMQ).  – The smallest quantity delivered for which the measurement is to within 
the applicable tolerances for  that system . [3.37, 3.39]  
 
N 
 
Non-resettable totalizer . – An element interfaced with the measuring or weighing element that indicates the 
cumulative registration of the measured quantity with no means to return to zero . [3.30, 3.37, 3.39]  
 
P 
 
point -of-sale system.  – An assembly of elements including a weighing or measuring element, an indicating element, 
and a recording element (and may also be equipped with a “scanner”) used to complete a direct sales transaction . 
[2.20, 3.30, 3.32, 3.37, 3.39]  
 
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remote  configuration capability.  – The ability to adjust a weighing or measuring device or change its sealable 
parameters from or through some other device that is not itself necessary to the operation of the weighing or 
measuring device or is not a permanent part of that device . [2.20, 2.21, 2.24, 3.30, 3.37, 3.39, 5.56( a)] 
 
retail  device.  – A measuring device primarily used to measure product for the purpose of sale to the end user . [3.30, 
3.32, 3.37, 3.39]  
 
W 
 
wet hose.  – A discharge hose intended to be full o f product at all times.  (Also see "wet -hose type." ) [3.30, 3.31, 
3.38, 3.39]  
 
wet-hose type . – A type of device designed to be operated with the discharge hose full of product at all times.  (Also 
see "wet hose." ) [3.30, 3.32, 3.34, 3.37, 3.38, 3.39]  Handbook 44 –  2016   3.40.  Electric Vehicle Fueling Systems –  Tentative Code  
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 Section 3.40.  Electric Vehicle Fueling Systems –  Tentative Code  
 
This tentative code has a trial or experimental status and is not intended to be enforced.  The requirements are 
designed for study prior to the development and adoption of a final code.  Officials wanting  to conduct an official 
examination of an Electric Vehicle Supply Equipment (EVSE) or system are advised to see paragraph 
G-A.3. Special and Unclassified Equipment.  
(Tentative Code Added 2015)  
A. Application  
A.1. General.  – This code applies to devices, accessories, and systems used for the measurement of electricity 
dispensed in vehicle fuel applications wherein a quantity determination or statement of measure is used wholly or 
partially as a basis for sale or upon which a charge for service is based.  
 
A.2. Exceptions.  – This code does not apply to:  
 
(e) The use of any measure or measuring device owned, maintained, and used by a public utility or 
municipality only in connection with measuring electricity subject to the authority having jurisdiction such 
as the Public Utilities Commission.  
 
(f) Electric Vehicle Supply Equipment (EVSEs) used solely for dispensing electrical energy in connection 
with operations in which the amount dispensed does not affect customer charges or compensation.  
 
(g) The wholesale delivery of electricity.  
 
A.3. Additional Code Requirements. –  In addition to the requirements of this code, Electric Fueling Systems 
shall meet the requirements of Section 1.10. General Code.  
 
A.3.1.  Electric Vehicle Supply Equ ipment (EVSE) with Integral Time -Measuring Devices.  – An EVSE 
that is used for both the sale of electricity as vehicle fuel and used to measure time during which services 
(e.g., vehicle parking) are received.  These devices shall also meet the requirements  of Section 5.55. Timing 
Devices.  
 
A.4. Type Evaluation. –  The National Type Evaluation Program (NTEP) will accept for type evaluation only 
those EVSEs that comply with all requirements of this code and have received safety certification by a nationally 
recognized testing laboratory (NRTL).  
S. Specifications  
S.1. Primary Indicating and Recording Elements.  
 
S.1.1.  Electric Vehicle Supply Equipment (EVSE) . – An EVSE used to charge electric vehicles shall 
be of the computing type and shall indicate the elect rical energy, the unit price, and the total price of each 
transaction.  
 
(a) EVSEs capable of applying multiple unit prices over the course of a single transaction shall also be 
capable of indicating the start and stop time, the total quantity of energy deliver ed, the unit price, and 
the total price for the quantity of energy delivered during each discrete phase corresponding to one of 
the multiple unit prices.  
 
(b) EVSEs capable of applying additional fees for time -based and other services shall also be capable of 
indicating the total time measured; the unit price(s) for the additional time based service(s); the total 3.40.  Electric Vehicle Fueling Systems –  Tentative Code   Handbook 44 –  2016  
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 computed price(s) for the time measured; and the total transaction price, including the total price for 
the energy and all additional fees.  
 
S.1.2.  EVSE Indicating Elements . – An EVSE used to charge electric vehicles shall include an indicating 
element that accumulates continuously and displays, for a minimum of 15  seconds at the activation by the user 
and at the start and end of the transactio n, the correct measurement results relative to quantity and total price.  
Indications shall be clear, definite, accurate, and easily read under normal conditions of operation of the device.  
All indications and representations of electricity sold shall be clearly identified and separate from other time-
based fees indicated by an EVSE that is used for both the sale of electricity as vehicle fuel and the sale of other 
separate time -based services (e.g., vehicle parking).   
 
S.1.2.1.  Multiple EVSEs Associated w ith a Single Indicating Element.  – A system with a single 
indicating element for two or more EVSEs shall be provided with means to display information from the 
individual EVSE(s) selected or displayed, and shall be provided with an automatic means to indic ate 
clearly and definitely which EVSE is associated with the displayed information.  
 
S.1.3.  EVSE Units.    
 
S.1.3.1.  EVSE Units of Measurement.  – EVSE units used to charge electric vehicles shall be indicated 
and recorded in megajoules (MJ) or kilowatt -hours (kWh) and decimal subdivisions thereof.  
 
S.1.3.2.  EVSE Value of Smallest Unit. – The value of the smallest unit of indicated delivery by an 
EVSE, and recorded delivery if the EVSE is equipped to record, shall be 0.005 MJ or 0.001 kWh.  
 
S.1.3.3.  Values Defined.  – Indicated values shall be adequately defined by a sufficient number of 
figures, words, symbols, or combinations thereof.  An indication of “zero” shall be a zero digit for all 
displayed digits to the right of the decimal mark and at least one to  the left.  
 
S.2. EVSE Operating Requirements.  
 
S.2.1.  EVSE Return to Zero.  
 
(c) The primary indicating and the primary recording elements of an EVSE used to charge electric 
vehicles, if the EVSE is equipped to record, shall be provided with a means for readil y returning the 
indication to zero either automatically or manually.  
 
(d) It shall not be possible to return primary indicating elements, or primary recording elements, beyond 
the correct zero position.  
 
S.2.2.  EVSE Indicator Zero Reset Mechanism.  – The reset mechanism for the indicating element of an 
EVSE used to charge electric vehicles shall not be operable during a transaction.  Once the zeroing operation 
has begun, it shall not be possible to indicate a value other than: the latest measurement; “all zeros;” blank the 
indication; or provide other indications that cannot be interpreted as a measurement during the zeroing 
operation.  
 
S.2.3.  EVSE Provision for Power Loss.  
 
S.2.3.1.  Transaction Information.  – In the event of a power loss, the information needed to complete 
any transaction (i.e., delivery is complete and payment is settled) in progress at the time of the power loss  
(such as the quantity and unit price, or sales price) shall be determinable t hrough one of the means listed 
below or the transaction shall be terminated without any charge for the electrical energy transfer to the 
vehicle:  
 
(a) at the EVSE;  
 
(b) at the console, if the console is accessible to the customer;  Handbook 44 –  2016   3.40.  Electric Vehicle Fueling Systems –  Tentative Code  
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(c) via on site internet access; or  
 
(d) through toll -free phone access.  
 
For EVSEs in parking areas where vehicles are commonly left for extended periods, the information 
needed to complete any transaction in progress at the time of the power loss shall be determinable through 
one of the above  means for at least eight hours.  
 
S.2.3.2.  Transaction Termination. –  In the event of a power loss, either:   
 
(a) the transaction shall terminate at the time of the power loss; or  
 
(b) the EVSE may continue charging without additional authorization if th e EVSE is able to 
determine it is connected to the same vehicle before and after the supply power outage.   
 
In either case, there must be a clear indication on the receipt provided to the customer of the interruption, 
including the date and time of the in terruption along with other information required under S.2.6. EVSE 
Recorded Representations.  
 
S.2.3.3.  User Information.  – The EVSE memory, or equipment on the network supporting the EVSE, 
shall retain information on the quantity of fuel dispensed and the  sales price totals during power loss.  
 
S.2.4.  EVSE Indication of Unit Price and Equipment Capacity and Type of Voltage.  
 
S.2.4.1.  Unit Price.  – An EVSE shall be able to indicate on each face the unit price at which the EVSE 
is set to compute or to dispense at any point in time during a transaction.  
S.2.4.2.  Equipment Capacity and Type of Voltage.  – An EVSE shall be able to conspicuously indicat e 
on each face the maximum rate of energy transfer (i.e., maximum power) and the type of current associated 
with each unit price offered (e.g., 7  kW AC, 25  kW DC, etc.).  
 
S.2.4.3.  Selection of Unit Price.  – When electrical energy is offered for sale at mor e than one unit price 
through an EVSE, the selection of the unit price shall be made prior to delivery through a deliberate action 
of the purchaser to select the unit price for the fuel delivery.  Except when the conditions for variable price 
structure have been approved by the customer prior to the sale, a system shall not permit a change to the 
unit price during delivery of electrical energy.  
Note:  When electrical energy is offered at more than one unit price, selection of the unit price may be through t he 
deliberate action of the purchaser:  1) using controls on the EVSE; 2) through the purchaser’s use of personal or 
vehicle -mounted electronic equipment communicating with the system; or 3) verbal instructions by the customer.  
S.2.4.4.  Agreement Between I ndications.  – All quantity, unit price, and total price indications within a 
measuring system shall agree for each transaction.  
 
S.2.5.  EVSE Money -Value Computations. –  An EVSE shall compute the total sales price at any 
single -purchase unit price for which the electrical  energy being measured is offered for sale at any delivery 
possible within either the measurement range of the EVSE or the range of the computing elements, whichever is 
less. 
 
S.2.5.1.  Money -Value Divisions Digital.  – An EVSE with digital in dications shall comply with the 
requirements of paragraph  G-S.5.5. Money -Values, Mathematical Agreement, and the total price 
computation shall be based on quantities not exceeding 0.5  MJ or 0.1 kWh.  
 
S.2.5.2.  Auxiliary Elements.  – If a system is equipped w ith auxiliary indications, all indicated money 
value and quantity divisions of the auxiliary element shall be identical to those of the primary element.  3.40.  Electric Vehicle Fueling Systems –  Tentative Code   Handbook 44 –  2016  
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S.2.6.  EVSE Recorded Representations. –  A receipt, either printed or electronic, providing the 
following information shall be available at the completion of all transactions:  
 
(e) the total quantity of the energy delivered with unit of measure; 
 
(f) the total computed price of the energy sale;  
 
(g) the unit price of the energy, and for systems capable of applying mult iple unit prices for energy during 
a single transaction, the following additional information is required: 
 
a. the start and stop time of each phase  during which one of the multiple unit prices was applied;  
 
b. the unit price applied during each pha se; 
 
c. the total quantity of energy delivered during each phase;  
 
d. the total purchase price for the quantity of energy delivered during each phase;  
 
(h) the maximum rate of energy transfer (i.e., maximum power) and type of current (e.g., 7  kW AC, 
25 kW DC, etc.);  
 
(i) any additional separate charges included in the transaction (e.g., charges for parking time) including:  
 
a. the time and date when the service begins and the time and date when the service ends; or the total 
time interval purchased, and the time and date th at the service either begins or ends;  
 
b. the unit price applied for the time -based service;  
 
c. the total purchase price for the quantity of time measured during the complete transaction;  
 
(j) the final total price of the complete transaction including all items;  
 
(k) the unique EVSE identification number;  
 
(l) the business name; and  
 
(m) the business location.  
 
S.2.7.  Indication of Delivery. –  The EVSE shall automatically show on its face the initial zero condition 
and the quantity delivered (up to the capacity of the indicat ing elements).  
 
S.3. Design of Measuring Elements and Measuring Systems.  
 
S.3.1.  Metrological Components.  – An EVSE measuring system shall be designed and constructed so 
that metrological components are adequately protected from environmental conditions li kely to be detrimental 
to accuracy.  The system shall be designed to prevent undetected access to adjustment mechanisms and terminal 
blocks by providing for application of a physical security seal or an audit trail.  
 
S.3.2.  Terminals.  – The terminals of th e EVSE system shall be arranged so that the possibility of short 
circuits while removing or replacing the cover, making connections, or adjusting the system, is minimized.  
 
S.3.3.  Provision for Sealing.  – Adequate provision shall be made for an approved means of security 
(e.g., data change audit trail) or physically applying security seals in such a manner that no adjustment may be 
made of:  
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 (a) each individual measurement element;  
 
(b) any adjustable el ement for controlling voltage or current when such control tends to affect the accuracy 
of deliveries;  
 
(c) any adjustment mechanism that corrects or compensates for energy loss between the system and 
vehicle connection; and  
 
(d) any metrological parameter  that detrimentally affects the metrological integrity of the EVSE or 
system.  
 
When applicable, the adjusting mechanism shall be readily accessible for purposes of affixing a security seal.  
Audit trails shall use the format set forth in Table S.3.3. Categ ories of Device and Methods of Sealing.  
 
Table S.3.3.  
Categories of Device and Methods of Sealing  
Categories of Device  Method of Sealing  
Category 1:   No remote configuration capability.  Seal by physical seal or two event counters: one for 
calibration parameters and one for configuration 
parameters.  
Category 2:   Remote configuration capability, but 
access is controlled by physical hardware.  
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capabl e of printing in this mode or shall not operate 
while in this mode.  The hardware enabling access for remote 
communication must be on -site.  The hardware must be 
sealed using a physical seal or an event counter for 
calibration parameters and an event counte r for 
configuration parameters.  The event counters may be 
located either at the individual measuring EVSE or at 
the system controller; however, an adequate number of 
counters must be provided to monitor the calibration 
and configuration parameters of the individual EVSEs 
at a location.  If the counters are located in the system 
controller rather than at the individual EVSE, means 
must be provided to generate a hard copy of the 
information through an on- site device.  
Category 3:   Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password). 
 
The device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode or shall not operate 
while in this mode.  An event logger is required in the device; it must 
include an event counter (000 to 999), the parameter 
ID, the date and time of the change, and the new value 
of the parameter.  A printed copy of the information 
must  be available through the EVSE or through another 
on-site device.  The event logger shall have a capacity 
to retain records equal to 10  times the number of 
sealable parameters in the EVSE, but not more than 
1000 records are required.  ( Note:   Does not requ ire 
1000 changes to be stored for each parameter.)  
 
S.3.4.  Data Storage and Retrieval.  
 
(a) EVSE data accumulated and indicated shall be unalterable and accessible.  
 
(b) Values indicated or stored in memory shall not be affected by electrical, mechanical, or temperature 
variations, radio -frequency interference, power failure, or any other environmental influences to the 
extent that accuracy is impaired.  
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 (c) Memory and/or display shall be recallable for a minimum of three years.  A replaceable battery shall 
not be used for this purpose.  
 
S.3.5.  Temperature Range for System Components.  – EVSEs shall be accurate and correct over the 
temperature range of –  40 °C to +  85 °C (−  40 °F to 185  °F).  If the system or any measuring system 
components are not capable of meeting these requirements, the temperature range over which the system is 
capable shall be stated on the NTEP CC, marked on the EVSE, and installations shall be limited to the narrower 
temperature limits.  
 
S.4. Connections.  
 
S.4.1.  Diversion of Measured Electricity.  – No means shall be provided by which any measured 
electricity can be diverted from the measuring device.  
 
S.4.1.1.  Unauthorized Disconnection.  – Means shall be provided to automatically terminate the 
transaction in the event that there is an  unauthorized break in the connection with the vehicle.  
 
S.4.2.  Directional Control.  – If a reversal of energy flow could result in errors that exceed the tolerance 
for the minimum measured quantity, effective means, automatic in operation to prevent or account for the 
reversal of flow shall be properly installed in the system.  (See N.3. Minimum Test Draft [Size])  
 
S.5. Markings.  – The following identification and marking requirements are in addition to the requirements of 
Section 1.10. General Code, parag raph G -S.1. Identification.  
 
S.5.1.  Location of Marking Information; EVSE.  – The marking information required in General Code, 
paragraph G -S.1. Identification shall appear as follows:  
 
(a) within 60  cm (24  in) to 150  cm (60  in) from ground level; and  
 
(b) on a portion of the EVSE that cannot be readily removed or interchanged (e.g., not on a service access 
panel).  
 
S.5.2.  EVSE Identification and Marking Requirements.  – In addition to all the marking requirements 
of Section 1.10. General Code, paragraph G -S.1. Identification, each EVSE shall have the following 
information conspicuously, legibly, and indelibly marked:  
 
(a) voltage rating;  
 
(b) maximum current deliverable;  
 
(c) type of current (AC or DC or, if capable of both, both shall be listed);  
 
(d) minimum measured quantity (MMQ); and  
 
(e) temperature limits, if narrower than and within –  20 °C to +  50 °C (−  4 °F to 122  °F). 
 
S.5.3.  Abbreviations and Symbols.  – The following abbreviati ons or symbols may appear on an EVSE 
system.  
 
(a) VAC = volts alternating current;  
 
(b) VDC = volts direct current;  
 
(c) MDA = maximum deliverable amperes;  
 
(d) J = joule.  Handbook 44 –  2016   3.40.  Electric Vehicle Fueling Systems –  Tentative Code  
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S.6. Printer.  – When a system is equipped with means for printing the measured quantity, the printed information 
must agree with the indications on the EVSE for the transaction and the printed values shall be clearly defined.  
 
S.6.1.  Printed Receipt.  – Any delivered, printed quantity shall include an EVSE identification number 
that uniquely identifies the EVSE from all other EVSEs within the seller’s facility, the time and date, and the 
name of the seller.  This information may be printed by the EVSE system or pre -print ed on the ticket.  
 
S.7. Totalizers for EVSE Systems.  – EVSE systems shall be designed with a nonresettable totalizer for the 
quantity delivered through each separate measuring device.  Totalizer information shall be adequately protected and 
unalterable.  T otalizer information shall be provided by the system and readily available on site or via on site 
internet access.  
 
S.8. Minimum Measured Quantity (MMQ).  – The minimum measured quantity shall satisfy the conditions of 
use of the measuring system as follows:  
 
(c) Measuring systems shall have a minimum measured quantity not exceeding 2.5  MJ or 0.5  kWh.  
N. Notes  
N.1. No Load Test.  – A no load test may be conduct ed on an EVSE measuring system by applying rated voltage 
to the system under test and no load applied.  
 
N.2. Starting Load Test.  – A system starting load test maybe conducted by applying rated voltage and 
0.5-ampere load.  
 
N.3. Minimum Test Draft (Size).  – Full and light load tests shall require test of the EVSE System for a delivery 
of the minimum measured quantity as declared by the manufacturer.  
 
N.4. EVSE System Test Loads.  – EVSE measuring system testing shall be accomplished by connecting the test 
load and test standard at the point where the fixed cord is connected to the vehicle.  Losses in the cord between the 
EVSE under test and the test standard should be automatically corrected for in the EVSE quantity indication for 
direct comparison to the te st standard and also while the EVSE is in normal operation.  For EVSEs that require a 
customer - supplied cord, system testing shall be accomplished by connecting the test load and test standard at the 
point where the customer’s cord is connected to the EVS E. 
 
N.5. Test of an EVSE System.  
 
N.5.1.  Performance Verification in the Field . – Testing in the field is intended to validate the transactional 
accuracy of the EVSE system.  The following testing is deemed sufficient for a field validation.  
 
N.5.2.  Accuracy Testing.  – The testing methodology compares the total energy delivered in a transaction 
and the total cost charged as displayed/reported by the EVSE with that measured by the measurement standard.  
 
(a) For AC systems:  
 
(1)  Accuracy test of the EVSE s ystem at a load of not less than 85  % of the maximum deliverable 
amperes (expressed as MDA) as determined from the pilot signal for a total energy delivered of at 
least twice the minimum measured quantity (MMQ).  If the MDA would result in maximum 
delivera ble power of greater than 7.2  kW, then the test may be performed at 7.2  kW. 
 
(2) Accuracy test of the EVSE system at a load of not greater than 10  % of the maximum deliverable 
amperes (expressed as MDA) as determined from the pilot signal for a total energ y delivered of at 
least the minimum measured quantity (MMQ).  
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 (d) For DC systems (see note):  
 
(1)  Accuracy test of the EVSE system at a load of not less than 85  % of the maximum deliverable 
amperes current (expressed as MDA) as determined from the digital communication message from 
the DC EVSE to the test standard for a total energy delivered of at least twice the minimum 
measured quantity (MMQ).  
 
(2) Accuracy test of the EVSE system at a load of not more than 10  % of the maximum deliverable 
amperes (expres sed as MDA) as determined from the digital communication message from the DC 
EVSE to the test standard for a total energy delivered of at least the minimum measured quantity 
(MMQ).  
 
Note:  For DC systems it is anticipated that an electric vehicle may be use d as the test load.  Under that 
circumstance, testing at the load presented by the vehicle shall be sufficient.  
 
N.6. Repeatability Tests.  – Tests for repeatability shall include a minimum of three consecutive tests at the same 
load, similar time period, e tc., and be conducted under conditions where variations in factors are reduced to 
minimize the effect on the results obtained.  
T. Tolerances  
T.1. Tolerances, General.  
 
(c) The tolerances apply equally to errors of underregistration and errors of overregistration.  
 
(d) The tolerances apply to all deliveries measured at any load within the rated measuring range of the EVSE.  
 
(e) Where instrument transformers or other components are used, the provisions of this section shall apply to 
all system components.  
 
T.2. Load Test Tolerances.  
 
T.2.1.  EVSE Load Test Tolerances .  – The tolerances for EVSE load tests are:  
  
(a) Acceotance Tolerance:  1.0  %; and  
 
(b) Maintenance Tolerance:  2.0  %. 
 
T.3. Repeatability.  – When multiple load tests are conducted at the same load condition, the range of the load test 
results shall not exceed 25  % of the absolute value of the maintenance tolerance and the results of each test shall be 
within the applicable tolerance.  
 
T.4. Tolerance Application in Type Evaluation Examinations for EV SEs.  – For type evaluation examinations, 
the acceptance tolerance values shall apply under the following conditions:  
 
(c) at any temperature, voltage, load, and power factor within the operating range of the EVSE, and  
 
(d) regardless of the influence factors in ef fect at the time of the conduct of the examination, and  
 
(e) for all quantities greater than the minimum measured quantity.  
 
T.5. No Load Test.  – An EVSE measuring system shall not register when no load is applied.   
 
T.6. Starting Load.  – An EVSE measuring system shall register a starting load test at a 0.5  ampere (A) load.  Handbook 44 –  2016   3.40.  Electric Vehicle Fueling Systems –  Tentative Code  
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 UR.  User Requirements  
UR.1.  Selection Requirements.  
 
UR.1.1.  Computing -Type Device; Retail EVSE.  – An EVSE used to charge electric vehicles shall be of the 
computing type and shall indicate the electrical energy, the unit price, and the total price of each delivery.  
 
UR.1.2.  Connection Cord- Length.  – An adequate means for cord management shall be in use when the cord 
exceeds 25  ft in length.  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Maximum Deliverable Current.  – The marked maximum deliverable current shall not exceed the 
total capacity in amperes of the EVSE or the thermal overload protectors of the installation site.  
 
UR.2.2.  Manufacturer’s Instructions.  – An EVSE shall be installed in accordance with the manufacturer’s 
instructions, and the installation shall be sufficiently secure and rigid to maintain this condition.  
 
UR.2.3.  Load Range.  – An EVSE shall be installed so that the current and voltage will not exceed the rated 
maximum values over which the EVSE is designed to operate continuously within the specified accuracy.  
Means to limit current and/or voltage shall be incorporated in th e installation if necessary.  
 
UR.2.4.  Regulation Conflicts and Permit Compliance.  – If any provision of Section UR.2.  Installation 
Requirements is less stringent than that required of a similar installation by the serving utility, the installation 
shall be  in accordance with those requirements of the serving utility.  
 
 The installer of any EVSE shall obtain all necessary permits.  
 
 UR.2.5.  Responsibility, Unattended EVSE.  – An unattended EVSE shall have clearly and conspicuously 
displayed thereon, or immediately adjacent thereto, adequate information detailing the name, address, and 
phone number of the local responsible party for the device.  
 
UR.3.  Use of EVSE.  
 
UR.3.1.  Unit Price for Retail EVSE Devices.  – The unit price at which the EVSE is set to compute shall be 
conspicuously displayed or posted on the face of the retail EVSE used in direct sale.  
UR.3.2.  Return of Indicating and Recording Elements to Zero.  – The primary indicating elements (visual) 
and the primary recording elements shall be returned to zero immediately before each transaction.   
 
UR.3.3.  EVSE Recorded Representations.  – A receipt, either printed or electronic, providing the following 
infor mation shall be available at the completion of all transactions:  
 
(a) the total quantity of the energy delivered with unit of measure; 
 
(b) the total computed price of the energy sale;  
 
(c) the unit price of the energy; and for systems capable of applying mult iple unit prices for 
energy during a single transaction, the following additional information is required: 
 
(1) the start and stop time of each phase  during which one of the multiple unit prices was applied;  
 
(2) the unit price applied during each phase;  
 
(3) the total qua ntity of energy delivered during each phase;  3.40.  Electric Vehicle Fueling Systems –  Tentative Code   Handbook 44 –  2016  
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(4) the total purchase price for the quantity of energy delivered during each phase;  
 
(d) the maximum rate of energy transfer (i.e., maximum power) and type of current (e.g., 
7 kW AC, 25  kW DC, etc.);  
 
(e) any additional separate charges included in the transaction (e.g., charges for parking time) 
including:  
 
(1) the time and date when the service begins and the time and date when the service ends; or the total 
time interval purchased, and the time and date that the service ei ther begins or ends;  
 
(2) the unit price applied for the time -based service;  
 
(3) the total purchase price for the quantity of time measured during the complete transaction;  
 
(f) the final total price of the complete transaction including all items;  
 
(g) the unique EVSE identification number;  
 
(h) the business name; and  
 
(i) the business location.  
 
UR.3.4.  EVSE in Operation.  – The EVSE shall be permanently, plainly, and visibly identified so that it is 
clear which EVSE and connector is in operation.  
 
UR.3.5.  Steps After Charging.  – After delivery to a customer from a retail EVSE: 
 
(c) the EVSE shall be shut -off at the end of a charge, through an automatic interlock that prevents 
subsequent charging until the indicating elements and recording elements, if the EVSE is equipped and 
activ ated to record, have been returned to their zero positions; and  
 
(d) the vehicle connector shall not be returned to its starting position unless the zero set -back interlock is 
engaged or becomes engaged by the act of disconnecting from the vehicle or the act o f returning the 
connector to the starting position.  
Appendix D.  Definitions  
The following includes new definitions to address Electric Vehicle Fueling Systems. Also included are those 
definitions currently found in Appendix D that are intended to apply to these systems.  The specific code(s) to which 
each definition applies is shown in [brackets] at the end of the definition.  Definitions for the General Code [1.10] 
apply to all codes in Handbook 44.  
 
A 
 
alternating current (AC).  – An electric current that reverses direction in a circuit at regular intervals. [3.40]  
 
ampere.  – The practical unit of electric current. It is the quantity of current caused to flow by a potential difference 
of one volt through a resistance of one ohm.  One ampere (A) is equal to the flow of one coulomb of charge per 
second.  One coulomb (C) is the unit of electric charge equal in magnitude to the charge of 6.24 × 1018 electrons. 
[3.40]  
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 audit trail.  – An electronic count and/or information record of the  changes to the values of the calibration or 
configuration parameters of a device. [1.10, 2.20, 2.21, 2.24, 3.30, 3.37, 3.39, 3.40, 5.56(a)]  
(Added 1993)  
 
C 
 
calibration parameter.  – Any adjustable parameter that can affect measurement or performance accuracy and, due 
to its nature, needs to be updated on an ongoing basis to maintain device accuracy (e.g., span adjustments, 
linearization factors, and coarse zero adjustments). [2.20,  2.21, 2.24, 3.30, 3.37, 3.39, 3.40, 5.56(a)]  
(Added 1993)  
 
configuration parameter.  – Any adjustable or selectable parameter for a device feature that can affect the accuracy 
of a transaction or can significantly increase the potential for fraudulent use of the device and, due to its nature, 
needs to be updated only during device installation or upon replacement of a component (e.g., division value 
[increment], sensor range, and units of measurement). [2.20, 2.21, 2.24, 3.30, 3.37, 3.40, 5.56(a)]  
(Added 1993)  
 
creep.  – A continuous apparent measurement of energy indicated by a system with operating voltage applied and no 
power consumed (load terminals open circuited). [3.40]  
 
current.  – The rate of the flow of electrical charge past any one point in a circu it.  The unit of measurement is 
amperes (A) or coulombs (C) per second. [3.40]  
 
D 
 
direct current (DC).  – An electric current that flows in one direction. [3.40]  
 
E 
 
electric vehicle, plug -in. – A vehicle that employs electrical energy as a primary or secondary mode of propulsion .  
Plug-in electric vehicles may be all- electric vehicles (EV’s) or plug -in hybrid electric vehicles (PHEV’s).  All-
electric vehicles are powered by an electric motor and battery at all times.  All -electric vehicles may also be called 
battery -electric vehicles (BEV’s).  Plug -in hybrid electric vehicles employ both an electric motor and an internal 
combustion engine that consumes either conventional or alternative fuel or a fuel cell.  In a parallel type hybrid -
electric vehicle, either the electric motor or the engine may propel the vehicle.  In a series type hybrid -electric 
vehicle, the engine or fuel cell generates electricity that is then used by the electric motor to propel the vehicle.  
EV’s, BEV’s, and PHEV’s are capable of r eceiving and storing electricity via connection to an external electrical 
supply.  Not all hybrid- electric vehicles are of the plug -in type.  Hybrid -electric vehicles that do not have the 
capability to receive electrical energy from an external supply (HEV ’s) generate electrical energy onboard with the 
internal combustion engine, regenerative braking, or both. [3.40]  
 
electric vehicle supply equipment (EVSE).  – A device or system designed and used specifically to transfer 
electrical energy to an electric ve hicle, either as charge transferred via physical or wireless connection, by loading a 
fully charged battery, or by other means . [3.40]  
 
electricity as vehicle fuel.  – Electrical energy transferred to and/or stored onboard an electric vehicle primarily for 
the purpose of propulsion . [3.40]  
 
energy.  – The integral of active power with respect to time. [3.40]  
 
energy flow.  – The flow of energy between line and load terminals (conductors) of an electricity system.  Flow from 
the line to the load terminals is co nsidered energy delivered.  Energy flowing in the opposite direction (i.e.,  from the 
load to line terminals) is considered as energy received. [3.40]  
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 equipment, commercial.  – Weights, measures, and weighing and measuring devices, instruments, elements, and 
systems or portion thereof, used or employed in establishing the measurement or in computing any basic charge or 
payment for services rendered on the basis of weight or me asure.  As used in this definition, measurement includes 
the determination of size, quantity, value, extent, area, composition (limited to meat and poultry), constituent value 
(for grain), or measurement of quantities, things, produce, or articles for dist ribution or consumption, purchased, 
offered, or submitted for sale, hire, or award. [1.10, 2.20, 2.21, 2.22, 2.24, 3.30, 3.31, 3.32, 3.33, 3.34, 3.35, 3.38, 
3.40, 4.40, 5.51, 5.56.(a), 5.56.(b), 5.57, 5.58, 5.59]  
(Added 2008)  
 
event counter.  – A nonresettable counter that increments once each time the mode that permits changes to sealable 
parameters is entered and one or more changes are made to sealable calibration or configuration parameters of a 
device. [2.20, 2.21, 3.30, 3.37, 3.39, 3. 40, 5.54, 5.56(a), 5.56(b), 5.57]  
(Added 1993)  
 
event logger.  – A form of audit trail containing a series of records where each record contains the number from the event 
counter corresponding to the change to a sealable parameter, the identification of the pa rameter that was changed, the time 
and date when the parameter was changed, and the new value of the parameter. [2.20, 2.21, 3.30, 3.37, 3.39, 3. 40, 5.54, 
5.56(a), 5.56(b), 5.57]  
(Added 1993)  
 
EVSE field reference standard.  – A portable apparatus that is t raceable to NIST and is used as a standard to test 
EVSEs in commercial applications.  This instrument is also known as a portable standard or working standard. 
[3.40] 
 
F 
 
face.  – That portion of a computing- type pump or dispenser which displays the actual computation of price per unit, 
delivered quantity, and total sale price.  In the case of some electronic displays, this may not be an integral part of 
the pump or dispenser. [3.30, 3. 40] 
(Added 1987)  
 
H 
 
hertz (Hz).  – Frequency or cycles per second.  One cycle of an alternating current or voltage is one complete set of 
positive and negative values of the current or voltage. [3.40]  
 
J 
 
megajoule (MJ).  – An SI unit of energy equal to 1  000 000 joules (J). [3.40]  
 
K 
 
kilowatt (kW).  – A unit of power equal to 1000 watts (W). [3.40]  
 
kilowatt -hour (kWh).   – A unit of energy equal to 1000 watthours (W  h). [3.40]  
 
L 
 
load, full. –  A test condition with rated voltage, current at 100  % of test amps level, and power factor of 1.0. [3.40]  
 
load, light. –  A test condition with rated voltage, current at 10  % of test amps level, and power factor of 1.0. [3.40]  
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 M 
 
master meter, electric. –  An electric watthour meter owned, maintained, and used for commercial billing purposes 
by the  serving utility.  All the electric energy served to a submetered service system is recorded by the master meter. 
[3.40]  
 
meter, electricity. –  An electric watthour meter. [3.40]  
 
metrological components. –  Elements or features of a measurement device or system that perform the measurement 
process or that may affect the final quantity determination or resulting price determinations.  This includes 
accessories that can affect the validity of transactions based upon the measurement process.  The measurement 
process includes determination of quantities; the transmission, processing, storage, or other corrections or 
adjustments of measurement data or values; and the indication or recording of measurement values or other derived 
values such as price or worth or charges. [3.40]  
 
N 
 
nationally recognized testing laboratory (NRTL).  – A laboratory that conducts testing and certification that is 
recognized by the Occupational Safety and Health Administration (OSHA). [3.40]  
 
nonresettable totalizer. –  An element interfaced with the measuring or weighing element that indicates the 
cumulative registration of the measured quantity with no means to return to zero. [3.30, 3.37, 3.39, 3.40]  
O 
 
ohm (Ω). – The practical unit of electric resistance that allows one ampere of current to flow when the impressed 
potential is one volt. [3.40]  
 
P 
 
percent registration.  – Percent registration is calculated as follows:  
 
100 Re xEVSEby measuredWhgistration PercentTANDARDSby measured Wh=
 
[3.40] 
 
power factor. –  The ratio of the active power to the apparent power in  an AC circuit.  The power factor is a number 
between 0 and 1 that is equal to 1 when the voltage and current are in phase (load is entirely resistive). [3.40]  
 
primary indicating or recording elements. –  The term “primary” is applied to those principal in dicating (visual) 
elements and recording elements that are designed to, or may, be used by the operator in the normal commercial use 
of a device.  The term “primary” is applied to any element or elements that may be the determining factor in arriving 
at th e sale representation when the device is used commercially.  (Examples of primary elements are the visual 
indicators for meters or scales not equipped with ticket printers or other recording elements and both the visual 
indicators and the ticket printers o r other recording elements for meters or scales so equipped.)  The term “primary” 
is not applied to such auxiliary elements as, for example, the totalizing register, or predetermined -stop mechanism 
on a meter or the means for producing a running record of successive weighing operations, these elements being 
supplementary to those that are the determining factors in sales representations of individual deliveries or weights.  
(See “indicating element” and “recording element.”). [1.10, 3.40]  
 
R 
 
recorded representation.  – The printed, electronically recorded, or other representation that retains a copy of the 
quantity and any other required information generated by a weighing or measuring device. [1.10, 3.40]  3.40.  Electric Vehicle Fueling Systems –  Tentative Code   Handbook 44 –  2016  
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recording element.  – An element incorporated, conne cted to, or associated with a weighing or measuring device by 
means of which its performance relative to quantity or money value is permanently recorded in a printed or 
electronic form. [1.10, 3.40]  
 
remote configuration capability.  – The ability to adjust a weighing or measuring device or change its sealable 
parameters from or through some other device that is not itself necessary to the operation of the weighing or 
measuring device or is not a permanent part of that device. [2.20, 2. 21, 2.24, 3.30, 3.37, 3.39, 3.40, 5.56(a)]  
(Added 1993)  
 
retail device.  – A measuring device primarily used to measure electrical energy for the purpose of sale to the end 
user. [3.40]  
 
S 
 
serving utility.  – The utility distribution company that owns the master meter and sells electric energy to the owner 
of a submeter system. [3.40]  
 
starting load.  – The minimum load above which the device will indicate energy flow continuously. [3.40]  
 
submeter.  – A system furnished, owned, installed, and maintained by the customer who is served through a utility 
owned master meter. [3.40]  
 
T 
 
test accuracy –  in-service.  – The device accuracy determined by a test made during the period that the system is in 
service.  It may be made on the customer’s premises without removing the system from its mounting or by removing 
the EVSE for testing either on the premises or in a labo ratory or shop. [3.40]  
 
test amperes (TA).  – The full load current (amperage) specified by the EVSE manufacturer for testing and 
calibration adjustment.  (Example:  TA  30). [3.40]  
 
thermal overload protector.  – A circuit breaker or fuse that automatically limits the maximum current in a circuit. 
[3.40]  
 
U 
 
unit price.  – The price at which the electrical energy is being sold and expressed in whole units of measurement. 
[1.10, 3.30, 3.40]  
(Added 1992)  
 
V 
 
vehicle connector.  – A device that by insertion into a vehicle inlet, establishes an electrical connection to the 
electric vehicle for the purpose of providing power and information exchange, with means for attachment of an 
electric vehicle cable.  This device is a part of th e vehicle coupler. [3.40]  
   
vehicle coupler.  – A means enabling the connection, at will, of an electric vehicle cable to the equipment.  It 
consists of a vehicle connector and a vehicle inlet. [3.40]  
 
vehicle inlet. –  The part incorporated in, or fixed to  the vehicle, which receives power from a vehicle connector. 
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 volt.  – The practical unit of electromotive force.  One volt will cause one ampere to flow when impressed across a 
resistance of one ohm. [3.40]  
W 
 
watt.  – The practical unit of electric power. In an alternating -current (AC) circuit, the power in watts is volts times 
amperes multiplied by the circuit power factor. [3.40]  
 
watthour (Wh).  – The practical unit of electric energy that is expended in one hour w hen the average power 
consumed during the hour is one watt. [3.40]  
 
 
 
 
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 Handbook 44 –  20152016   4.40.  Vehicle Tanks Used as Measures  
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 Section 4.40.  Vehicle Tanks Used as Measures  
 
A. Application  
 
A.1. General.  – This code applies to vehicle tanks when these are used as commercial measures.  
 
A.2. Exceptions.  – This code does not apply to the following devices:  
 
(a) Devices used solely for dispensing a product in connection with operations in which the amount dispensed 
does not affect customer charges.  
 (b) Meters mounted on vehicle tanks (for which see Section  3.31. Code for Vehicle -Tank Meters).  
 A.3. Additional Code Requirements.  – In addition to the requirements of this code, Vehicle Tanks Used as 
Measures shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Compartments.  
 
S.1.1.  Compartment Distortion.  – The shell and bulkheads of a vehicle tank shall be so constructed that 
under any condition of liquid lading they w ill not become distorted sufficiently to cause a change in the capacity 
of any compartment (as determined by volumetric test) equal to more than 0.25  L per 750 L (0.5  pt per 200 gal), 
or fraction thereof, of the nominal compartment capacity, or to more tha n 0.5  L (1 pt), whichever is greater.  
(This specification prescribes a limit on permissible distortion only, and is not to be construed as setting up a 
secondary tolerance on compartment capacities to be added to the values given in tolerance paragraph  T.2. Tolerance Values.)  
 
S.1.2.  Venting.  – During filling operations, effective venting of a compartment shall be provided to 
permit air to escape from all spaces designed to be filled with liquid and to permit the influx of air to the 
compartment during the discharge of liquid therefrom.  Venti ng shall prevent any formation of air pockets.  
 
S.1.3.  Completeness of Delivery.  – A tank shall be so constructed that, when it is standing on a level 
surface, complete delivery can be made from any compartment through its delivery faucet or valve whether 
other compartments are full or empty, and whether or not the delivery is through a manifold.  
 
S.1.4.  Fill or Inspection Opening.  – The fill or inspection opening of a compartment shall be of such 
size and location that it can readily be determined by visual inspection that the compartment has been properly 
filled or completely emptied and shall be so positioned with respect to the ends of the compartment that the 
indicator may be positioned as required.  In no case shall the opening, if circular, have a dia meter of less than 
20 cm (7
5/8 in), or, if other than circular, have an effective area of less than 290  cm2 (45 in2). 
 
S.1.5.  Dome Flange and Baffle Plates.  – Any dome flange extending into a compartment shall be 
provided with sufficient perforations or openings flush with the compartment shell to prevent any trapping of 
air.  All baffle plates in a compartment shall be so cut away at top and bottom, and else where as necessary, as to 
facilitate loading and unloading.  
 
S.1.6.  Compartment and Piping Capacities and Emergency Valve.  – If a compartment is equipped 
with an emergency (or safety) valve, this shall be positioned at the lowest point of outlet from the c ompartment, 
and the compartment capacity or capacities shall be construed as excluding the capacity of the piping leading 
therefrom.  However, the capacity of the piping leading from such a compartment shall be separately 
determined and reported, and may b e separately marked as specified in S.4. Marking of Compartments.  
 
S.1.6.1.  On Vehicle Tanks Equipped for Bottom Loading.  – On equipment designed for bottom 
loading, the compartment capacity shall include the piping of a compartment to the valve located on  the 4.40.  Vehicle Tanks Used as Measures   Handbook 44 –  20152016  
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 upstream side of the manifold and immediately adjacent thereto or, if not manifolded, to the outlet valve, 
provided that on or immediately adjacent to the marking as specified in S.4. Marking of Compartments the 
following words or a statement of similar meaning shall be affixed:  “Warning:  Emergency valves must be 
opened before checking measurement.”  
 
S.1.7.  Expansion Space.  – When a compartment is filled to the level of the highest indicator in the 
compartment, there shall remain an expansion space o f at least 0.75  % of the nominal compartment capacity as 
defined by that indicator.  
 
S.2. Design of Compartment Indicators.  
 
S.2.1.  General.  – An indicator shall be so designed that it will distinctly and unmistakably define a 
capacity point of its compartment when liquid is in contact with the lowest portion of the indicator.  
 
S.2.2.  Number of Indicators.  – In no case shall a compartment be p rovided with more than five 
indicators.  
(Amended 1972)  
 S.2.3.  Identification of Multiple Indicators.  – If a compartment is provided with multiple indicators, 
each such indicator shall be conspicuously marked with an identifying letter or number.  
 
S.2.4.  Location.  – An indicator shall be located:  
 
(a) midway between the sides of its compartment;  
 
(b) as nearly as practicable midway between the ends of its compartment, and in no case offset by more 
than 10  % of the compartment space or 15  cm (6  in), whicheve r is less;  
(Amended 1972)  
 
(c) so that it does not extend into, nor more than 15 cm (6  in) from that section of the compartment 
defined by a vertical projection of the fill opening;  
(Amended 1974)  
 (d) at a depth, measuring from the top of the dome opening, not lower than 46  cm (18  in) for fill openings 
of less than 38  cm (15  in) in diameter, or, if other than circular, an effective area of less than 1130  cm
2 
(175 in2), and not lower than 61  cm (24  in) for larger fill openings; and  
 
(e) to provide a clearance of not less than 5  cm (2  in) between indicators.  
 
S.2.5.  Permanence.  – Any indicator that is not intended to remain adjustable and all brackets or supports 
shall be securely welded in position.  
 
S.2.6.  Adjustable Indicators.  – Adequate provision shall be made for conveniently affixing a security 
seal or seals:  
 
(a) to any indicator intended to remain adjustable, so that no adjustment of the indicator can be made 
without mutilating or destroying the seal; and  
 (b) to any removable part to which an indicator may be attached, so that the part cannot be removed 
without mutilating or destroying the seal.  
 
S.2.7.  Sensitiveness.  – The position of any indicator in its compartment shall be such that at the level of 
the indicator a change of 1.0  mm (0.04 in) in the height of the liquid surface will represent a volume change of 
not more than the value of the tolerance for the nominal  compartment capacity as defined by that indicator.  
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 S.3. Design of Compartment Discharge Manifold.  – When two or more compartments discharge through a 
common manifold or other single outlet, effective means shall be provided to ensure that:  
 
(a) liquid ca n flow through the delivery line leading from only one compartment at one time and that flow of 
liquid from one compartment to any other is automatically prevented; or  
 
(b) all compartments will discharge simultaneously.  
 If the discharge valves from two or more compartments are automatically controlled so that they can only be 
operated together, thus effectively connecting these compartments to one another, such compartments shall, for 
purposes of this paragraph, be construed to be one compartment.  
 
S.4. Marking of Compartments.  
 
S.4.1.  Compartment Identification.  – Each compartment of a multiple -compartment tank shall be 
conspicuously identified by a letter or number marked on the dome or immediately below the fill opening.  
Such letters or numbers shall be in regular sequence from front to rear, and the delivery faucets or valves shall 
be marked to correspond with their respective compartments.  
 
S.4.2.  Compartment Capacity, Single Indicator.  – A compartment provided with a single indicator 
shall be clearly, permanently, and conspicuously marked with a statement of its capacity as defined by its 
indicator.  
 
S.4.3.  Compartment Capacity, Multiple Indicators.  – A compartment provided with two or more 
indicators shall be clearly, permanently, and conspicuously marked with a statement identifying:  
 
(a) each indicator by a letter or number;  and  
 
(b) immediately adjacent to each letter or number, the capacity of the compartment as defined by the 
particular indicator.  
 
N. Notes  
 
N.1. Test Liquid.  – Water or light fuel oil shall be used as the test liquid for a vehicle -tank compartment.  
 
N.2. Evaporation and Volume Change.  – Care shall be exercised to reduce to a minimum, evaporation losses 
and volume changes resulting from changes in temperature of the test liquid.  
 N.3. To Deliver.  – A vehicle -tank compartment shall be gauged “to deliver.”  If the compartment is gauged by  
measuring the test liquid into the tank, the inside tank walls shall first be thoroughly wetted.  
 N.4. Gauging of Compartments.  – When a compartment is gauged to determine the proper position for an 
indicator or to determine what a capacity marking should  be, whether on a new vehicle tank or following repairs or 
modifications that might affect compartment capacities, tolerances are not applicable, and the indicator shall be set 
and the compartment capacity shall be marked as accurately as practicable.  
 
N.5. Adjustment and Remarking.  – When a compartment is found upon test to have an error in excess of the 
applicable tolerance, the capacity of the compartment shall be adjusted to agree with its marked capacity, or its marked capacity shall be changed to agree with its capacity as determined by the test.  
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 T. Tolerances  
 
T.1. Application.  
 
T.1.1.  To Excess and to Deficiency.  – The tolerances hereinafter prescribed shall be applied to errors in 
excess and in deficiency.  
 
T.2. Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table 1. Maintenance and 
Acceptance Tolerances on Vehicle -Tank Compartments.  
 
Table 1.  
Maintenance and Acceptance Tolerances on Vehicle- Tank Compartments  
Nominal Capacity of Compartment  Maintenance and Acceptance Tolerances  
Gallons  Expressed in Quarts  Expressed in Gallons  
200 or less  2 0.5 
201 to 400, inclusive  3 0.75 
401 to 600, inclusive  4 1.0 
601 to 800, inclusive  5 1.25 
801 to 1000, inclusive  6 1.50 
over 1000  Add 1  quart per 200 gallons or 
fraction thereof  Add 0.25  gallon per 200  gallons or 
fraction thereof  
 
UR. User Requirements  
 
UR.1.  Conditions of Use.  
 
UR.1.1.  Filling.  – A vehicle shall stand upon a level surface during the filling of a compartment.  
 
UR.1.2.  Delivering.  – During a delivery, a vehicle shall be so positioned as to assure complete emptying of a 
compartment.  Each compartment shall be used for an individual delivery only; that is, an individual delivery 
shall consist of the entire contents of a compartment o r compartments.  
(Amended 1976)  
 Handbook 44 –  20152016   4.41.  Liquid Measures  
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 Section 4.41.  Liquid Measures 
 
 
A. Application  
 
A.1. General.  – This code applies to liquid measures; that is, to rigid measures of capacity designed for general 
and repeated use in the measurement of liquids.  
 A.2. Exceptions.  – The code does not apply to test measures or other volumetric standards.  
 A.3. Additional Code Requirements . – In addition to the requirements of this code, Liquid Measures shall meet 
the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Units.  
 
(a) The capacity of a liquid measure shall be 0.1  L, 0.2  L, 0.5  L, 1 L, 2 L, 5 L, or a multiple of 5  L, and the 
measure shall not be subdivided.  
 
(b) The capacity of a liquid measure shall be 1  gill, ½  liq pt, 1  liq pt, 1  liq qt, ½  gal, 1¼  gal, 1½  gal, or a 
multiple of 1  gal, and the measure shall not be subdivided.  However, 3  pt and 5 pt brick molds and 2½  gal 
(10 qt) cans shall be permitted when used exclusively for ice cream.  
 
S.2. Material.  – Measures shall be made of metal, glass, earthen ware, enameled ware, composition, or similar and 
suitable material.  If made of metal, the thickness of the metal shall not be less than the appropriate value given in 
Table  1. Minimum Thickness of Metal for Liquid Measures.  
 
 
S.3. Capacity Point.  – The capacity of a measure shall be determined to a definite edge, or to the lowest portion 
of a plate, bar, or wire, at or near the top of the measure, and shall not include the capacity of any lip or rim that may 
be provided.  
 
S.4. Reinforcing Rings.  – Reinforcing rings, if used, shall be attached to the outside of the measure and shall 
show no divisions or lines on the inside surface of the measure.  
 S.5. Discharge.  – A measure equipped with a discharge faucet or valve shall be susceptible to complete discharge 
through the faucet or valve when the measure is standing on a level surface.  
 
S.6. Marking Requirements.  – A measure shall be marked on its side with a statement of its capacity.  If the 
capacity is stated in terms of the pint or quart, the word “Liquid” or the abbreviation “Liq” shall be included.  
 Table 1.  
Minimum Thickness of Metal for Liquid Measures  
Nominal Capacity Minimum Thickness  
For Iron or Steel, Plated, or Unplated  
(inch)  For Copper or Aluminum  
(inch)  
1 pint or less  0.010  0.020  
1 quart, ½  gallon, 1  gallon  0.014  0.028  
Over 1  gallon  0.016  0.032  4.41.  Liquid Measures   Handbook 44 –  20152016  
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Agency No. 209.02  
 T. Tolerances  
 
T.1. – Maintenance tolerances in excess and in deficiency shall be as shown in Table 2. Maintenance Tolerances, in 
Excess and in Deficiency, for Liquid Measures.  Acceptance tolerances shall be one- half the maintenance tolerances.  
 
Table 2.  
Maintenance Toleran ces, in Excess and in Deficiency, for Liquid Measures  
Nominal Capacity Tolerance 
In Excess  In Deficiency  
fluid drams  cubic inches  fluid drams  cubic inches  
½ pt or less  2.0 0.4 1.0 0.2 
1 pt 3.0 0.7 1.5 0.3 
1 qt 4.0 0.9 2.0 0.5 
½ gal 6.0 1.4 3.0 0.7 
 fluid ounces  cubic inches  fluid drams  cubic inches  
1 and 1¼  gal 1.0 1.8 4.0 0.9 
1½ gal 1.5 2.7 6.0 1.4 
 fluid ounces  cubic inches  fluid ounces  cubic inches  
2 gal 2.0 3.5 1.0 1.8 
3 and 4  gal 4.0 7.0 2.0 3.6 
5 gal 6.0 11.0 3.0 5.4 
10 gal 10.0 18.0 5.0 9.0 
 Handbook 44 –  20152016   4.42.  Farm Milk Tanks  
  Markup Copy 
  Agency No. 209.02  
 Section 4.42.  Farm Milk Tanks 
 
 
A. Application  
 
A.1. General.  – This code applies to farm milk tanks on the premises of producers when these are used, or are to 
be used, for the commercial measurement of milk.  
 A.2. Exceptions.  – This code does not apply to tanks mounted on highway vehicles.  
 A.3. Additional Code Re quirements . – In addition to the requirements of this code, Farm Milk Tanks shall meet 
the requirements of Section  1.10. General Code.  
 
S. Specifications  
 S.1. Components.  – A farm milk tank, whether stationary or portable, shall be considered suitable for commercial 
use only when it comprises:  
 
(a) a vessel, whether or not it is equipped with means for cooling its contents;  
 (b) a means for reading the level of liquid in t he tank, such as a removable gauge rod or surface gauge; and  
 (c) a chart for converting level -of-liquid readings to volume.  
 
Each compartment of a subdivided tank shall, for the purposes of this code, be construed to be a farm milk tank.  
 
S.2. Design of T ank.  
 
S.2.1.  Level.  – A farm milk tank shall be designed to be in normal operating position when it is in level.  
The tank shall be so constructed that it will maintain its condition of level under all normal conditions of lading.  
 
S.2.2.  Level -Indicating Means.  – A tank shall be permanently equipped with sensitive means by which 
the level of the tank can be determined.  
 
S.2.2.1.  On a Stationary Tank.  – A stationary tank shall be provided with such level -indicating means 
as a two -way or circular level, a plumb bob, two- way leveling lugs, or the like; or the top edge or edges of 
the tank shall be so constructed throughout as to provide an accurate refer ence for level determinations; 
provided, that when leveling lugs or the top edge or edges of the tank are used as the reference for level determinations, there shall be supplied with the tank a sensitive spirit level of appropriate dimensions, and 
the posi tions where such level is intended to be used shall be permanently marked on the reference surface 
of the tank; and provided further, that when leveling lugs are used they shall be so designed, constructed, 
and installed at the factory that any alteration of the original position or condition, such as by hammering or 
filing, would be difficult and would become obvious.  A stationary tank with a nominal capacity of 2 000 L 
or 500  gal, or greater shall be provided with at least two similar level -indicating me ans, and these shall be 
located in opposite and distant positions from each other to facilitate an accurate level determination in both directions of the tank’s horizontal plane.  
(Amended 1980)  
 S.2.2.2.  On a Portable Tank.  – A portable tank shall be provi ded with either a two -way or a circular 
level.  
 
S.2.3.  Portable Tank.  – A portable tank shall be of the center -reading type; that is, it shall be so 
designed that the gauge rod or surface gauge, when properly positioned for use, will be approximately in th e 
vertical axis of the tank, centrally positioned with respect to the tank walls.  
 4.42.  Farm Milk Tanks   Handbook 44 –  20152016  
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Agency No. 209.02  
 S.2.4.  Capacity.  – A farm milk tank shall be clearly and permanently marked on a surface visible after 
installation with its capacity as determined by the manufacturer.  The  capacity shall not exceed an amount that 
can be agitated without overflowing and that can be measured accurately with the liquid at rest.  
[Nonretroactive as of January  1, 1979]  
 
S.3. Design of Indicating Means.  
 
S.3.1.  General.  – A tank shall include indicating means and shall be calibrated over the entire range of 
the volume of the tank from 5 % of capacity or 2  m3 (500 gal) whichever is less, to its maximum capacity.  
[Nonretroactive as of January  1, 1986]  
(Added 1985)  
 
S.3.2.  Gauge-Rod Bracket or Supports.  – If a tank is designed for use with a gauge rod, a substantial 
and rigid gauge -rod bracket or other suitable supporting elements for positioning the gauge rod shall be 
provided.  A gauge rod and its brackets or other supportin g elements shall be so constructed that, whenever the 
rod is placed in engagement with the bracket or supports and released, the rod will automatically seat itself at a fixed height and in a vertical position.  When a gauge rod is properly seated on its br ackets or supports, there 
shall be a clearance of at least 7.5  cm (3  in) between the graduated face of the rod and any tank wall or other 
surface that it faces.  
 
S.3.3.  Gauge Rod.  – When properly seated in position, a rod shall not touch the bottom of the tank 
unless this is required by the design of the supporting elements.  The rod shall be graduated throughout an 
interval corresponding to the volume range within which readings of liquid level are to be made.  
 S.3.4.  Surface -Gauge Bracket or Supports.  – If a tank is designed for use with a surface gauge, a 
substantial and rigid surface -gauge bracket or other suitable supporting elements for positioning the surface 
gauge shall be provided.  A surface gauge and its brackets or other supporting elements s hall be so constructed 
that, whenever the gauge assembly is placed in engagement with the bracket or supports, the indicator, if not 
permanently mounted on the tank, will automatically seat itself in correct operating position, and the graduated 
element will be vertically positioned and will be securely held at any height to which it may be manually set.  
 
S.3.5.  Surface Gauge.  – When properly engaged with its bracket and set to its lowest position, a surface 
gauge shall not touch the bottom of the tank.  The gauge shall be graduated throughout an interval 
corresponding to the volume range within which readings of liquid level are to be made.  
 
S.3.6.  External Gauge Assemblies.  
 
S.3.6.1.  Design and Installation.  – The gauge assembly shall be designed to meet sanitary requirements 
and shall be readily accessible for cleaning purposes.  The gauge assembly shall be mounted in a vertical 
position and equipped with a sliding mechanism to assist in determining the liqu id level.  
 
S.3.6.2.  Gauge Tube.  – The gauge tube shall be borosilicate glass or approved rigid plastic or rigidly 
supported flexible tubing with a uniform internal diameter not less than 2  cm (¾  in).  It shall be designed 
and constructed so that all produc t in the gauge can be discarded in such a manner that no product in the 
gauge tube will enter the discharge line or tank.  
(Amended 1983)  
 S.3.6.3.  Scale Plate.  – The scale plate shall be mounted adjacent to and parallel with the gauge tube and 
be no more t han 7  mm (¼  in) from the tube.  
 S.3.6.4.  Scale Graduations.  – The graduation lines shall be clear and easily readable and shall comply 
with the requirements of paragraphs included under S.3.7. Graduations.  
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  Agency No. 209.02  
 S.3.6.5.  Venting.  – An external gauge tube shall be adequately vented at the top, open to the 
atmosphere.  Any attachment to the gauge tube shall not adversely affect the operation of this vent.  
(Added 1984)  
(Added 1977)  
 
S.3.7.  Graduations.  
 
S.3.7.1.  Spacing and Width of Graduations.  – On a gauge rod or surface gauge, the spacing of the 
graduations, center to center, shall be not more than 1.6  mm (0.0625 in or 1/16 in) and shall not be less than 
0.8 mm (0.03125 in or 1/32 in).  The graduations shall not be less than 0.12 mm (0.005 in) in width, and the 
clear interval between adjacent edges of successive graduations shall be not less than 0.4  mm (0.015625 in 
or 1/64 in). 
 
S.3.7.2.  Values of Graduations.  – On a gauge rod or surface gauge, the graduations may be designated 
in inches or in centimeters and fractions thereof, or may be identified in a numerical series without 
reference to inches or centimeters or fractions thereof.  In either case, a volume chart shall be provided for 
each such rod or gauge and each tank with which it is asso ciated, showing values in terms of the graduation 
on the rod or gauge.  If a rod or gauge is associated with but one tank, in lieu of linear or numerical series 
graduations and volume chart, values in terms of volume of liquid in the tank may be shown dire ctly on the 
rod or gauge.  
 
S.3.7.3.  Value of Graduated Interval.  – The value of a graduated interval on a gauge rod or surface 
gauge (exclusive on the interval from the bottom of the tank to the lowest graduation) shall not exceed:  
 
(a) 2 L for a tank of a  nominal capacity of 1000 L or less; ½  gal for a tank of a nominal capacity of 
250 gal or less;  
 
(b) 4 L for a tank of a nominal capacity of 1001 L to 2000 L, inclusive; 1  gal for a tank of a nominal 
capacity of 251  gal to 500 gal, inclusive;  
 
(c) 6 L for a tank of a nominal capacity of 2001  L to 6000 L, inclusive; 1½  gal for a tank of a nominal 
capacity of 501  gal to 1500  gal, inclusive;  
 
(d) 8 L for a tank of a nominal capacity of 6001  L to 10  000 L, inclusive; 2  gal for a tank of a nominal 
capacity of 15 01 gal to 2500 gal, inclusive; or  
 (e) 8 L plus 4  L for each additional 10 000 L or fraction thereof, for tanks of nominal capacity above 
10 000 L or 2  gal plus 1  gal for each additional 2500  gal or fraction thereof, for tanks with 
nominal capacity above 2 500 gal. 
(Amended 1980)  
 
S.3.8.  Design of Indicating Means on Tanks with a Capacity Greater than 8000 Liters or 
2000 Gallons.  – Any farm milk tank with a capacity greater than 8000 L, or 2000 gal, shall be equipped with an 
external gauge assembly.  
[Nonretroactive and applicable only to tanks manufactured after January  1, 1981]  
(Added 1980)  
 4.42.  Farm Milk Tanks   Handbook 44 –  20152016  
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Agency No. 209.02  
 S.4. Design of Volume Chart.  
 
S.4.1.  General.  – A volume chart shall show volume values only, over the entire range of the volume of 
the tank from 5 % of capacity or 2  m3 (500 gal) whichever is less, to its maximum capacity.*  All letters and 
figures on the chart shall be distinct and easily readable.  The chart shall be substantially constructed, and the face of the chart shall be so protected that its lett ering and figures will not tend easily to become obliterated or 
illegible.  
[*Nonretroactive as of January  1, 1986]  
(Amended 1985)  
 
S.4.2.  For a Tank of 1 000 Liters, or 250  Gallons, or Less.  – The volume chart for a tank of nominal 
capacity of 1 0001000 L, or 250 gal, or less shall show values at least to the nearest 1  L, or ¼  gal. 
 
S.4.3.  For a Tank of 1 001 Liters to 2000  Liters, or 251 to 500 Gallons.  – The volume chart for a tank 
of nominal capacity of 1 0011001 L to 2 000 2000 L, or 251 gal to 500 gal, inclusive, shall show values at least 
to the nearest 2  L, or ½  gal. 
 
S.4.4.  For a Tank of Greater than 2 0002000 Liters, or 500  Gallons.  – The volume chart for a tank of 
nominal capacity of greater than 2 0002000 L, or 500  gal, shall show values at least to the nearest gallon, or 4  L. 
(Amended 1980)  
 
S.5. Gauging.  
 
S.5.1.  Level.  – A farm milk tank shall be level, as shown by the level -indicating means, during the 
original gauging operation.  
 
S.5.2.  To Deliver.  – A farm milk tank shall be originally gauged “to deliver.”  If the tank is gauged by 
measuring the test liquid into the tank, the inside tank walls shall first be thoroughly wetted and the tank shall 
then be drained for 30 seconds after the main drainage flow has ceased.  
 S.5.3.  Preparation of Volume Chart.  – When a tank is gauged for the purposes of preparing a volume 
chart, tolerances are not applicable, and the chart shall be prepared as accurately as practicable.  
 S.6. Identification.  – A tank and any  gauge rod, surface gauge, spirit level, and volume chart intended to be used 
therewith shall be mutually identified, as by a common serial number, in a prominent and permanent manner.  
 
N. Notes  
 
N.1. Test Liquid.  – Water shall be used as the test liquid for a farm milk tank.  
 
N.2. Evaporation and Volume Change.  – Care shall be exercised to reduce to a minimum, evaporation losses 
and volume changes resulting from changes in temperature of the test liquid.  
 N.3. To Deliver.  – A farm milk tank shall be tested “to deliver.”  If the tank is gauged by measuring the test liquid 
delivered into the tank, the inside tank walls shall first be thoroughly wetted and the tank then shall be drained for 30 seconds after the main d rainage flow has ceased.  
 
N.4. Level.  – A farm milk tank shall be level, as shown by the level -indicating means, during gauging and testing.  
 N.5. Test Methods.  – Acceptance tests of milk tanks may be of either the prover method or the master meter 
method provided that the master metering system is capable of operating within 25  % of the applicable tolerance 
found in T.3. Basic Tolerance Values.  Subsequent tests may be of either the prover method or the master meter method provided that the master metering  system is capable of operating within 25  % of the applicable tolerance 
found in T.4. Basic Tolerance Values, Master Meter Method.  
 Handbook 44 –  20152016   4.42.  Farm Milk Tanks  
  Markup Copy 
  Agency No. 209.02  
 N.5.1.  Verification of Master Metering Systems.  – A master metering system used to gauge a milk 
tank shall be verified before and after the gauging process.   A master metering system used to calibrate a milk 
tank shall be verified before starting the calibration and re- verified at least every quarter of the tank capacity, or 
every 2000 L (500 gal), whichever is greater. The above process of re- verifying the master metering system 
may be waived if the system is verified using a NIST traceable prover with a minimum of two tests immediately 
before and one test immediately after the gauging process and that each test result is within 25  % of T.3. Basic 
Tolerance Values.  
(Added 2001) (Amended 2012)   
 
N.5.2.  Temperature Changes in Water Supply.  – When using a master metering system to gauge or 
calibrate a milk tank, the official shall monitor the temperature of the water before an d after changing sources of 
supply.  If the water temperature of the new source changes by more than 2.8  °C (5  °F) from the previous 
supply, the official shall re -verify the accuracy of the master metering system as soon as possible after the 
system reache s temperature equilibrium with the new supply source.  
(Added 2001)  
 
N.6. Reading the Meniscus.  – When a reading or setting is to be obtained from a meniscus formed by milk or 
other opaque liquid, the index or reading line is the position of the highest poi nt of the center of the meniscus.  
When calibrating a device with water and the device is to be used with an opaque liquid, the reading should be obtained accordingly; that is, the position of the highest point of the center of the meniscus.  
(Added 1984)  
 
T. Tolerances  
 T.1. Application.  – The tolerances hereinafter prescribed shall be applied equally to errors in excess and errors in 
deficiency.  
 
T.2. Minimum Tolerance Values.  – On a particular tank, the maintenance and acceptance tolerance applied shall 
be not smaller than the volume corresponding to the graduated interval at the point of test draft on the indicating 
means or 2  L (½  gal), whichever is greater.  
(Amended 1980)  
 T.3. Basic Tolerance Values.  – The basic maintenance and acceptance tolerance shall be 0.2  % of the volume of 
test liquid in the tank at each test draft.  
(Amended 1975)  
 T.4. Basic Tolerance Values, Master Meter Method.  – The basic maintenance and acceptan ce tolerance for 
tanks tested by the master meter method shall be 0.4  % of the volume of test liquid in the tank at each test draft.  
(Added 1975)  
 
UR. User Requirements  
 
UR.1.  Installation.  – A stationary tank shall be rigidly installed in level without th e use of removable blocks or 
shims under the legs.  If such tank is not mounted permanently in position, the correct position on the floor for each 
leg shall be clearly and permanently defined.  
 
UR.2.  Level Condition.  
 
UR.2.1.  Stationary Tank.  – A stationary farm milk tank shall be maintained in level.  
 
UR.2.1.1.  Leveling Lugs.  – If leveling lugs are provided on a stationary tank, such lugs shall not be 
hammered or filed to establish or change a level condition of the tank.  
 4.42.  Farm Milk Tanks   Handbook 44 –  20152016  
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Agency No. 209.02  
 UR.2.2.  Portable Ta nk. – On a portable tank, measurement readings shall be made only when the tank is 
approximately level; that is, when it is not out of level by more than 5  % or approximately three degrees in any 
direction.  
 
UR.3.  Weight Chart.  – An auxiliary weight chart may be provided, on which shall be prominently displayed the 
weight per unit volume value used to derive the weight values from the official volume chart.  
 
UR.4.  Use. – A farm milk tank shall not be used to measure quantities greater than an amount that ca n be agitated 
without overflowing.  
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  Agency No. 209.02  
  
 
 
 
 
 
 
 
 
 
  
  
 
 
 
 
 
 
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 Handbook 44 –  20152016  4.43.  Measure- Containers  
 Markup Copy 
  Agency No. 209.02  
 Section 4.43.  Measure -Containers  
 
 
A. Application  
 A.1. General.  – This code applies to measure -containers, including lids or closures if such are necessary to 
provide total enclosure of the measured commodity, as follows:  
 
(a) Retail measure -containers intended to be used only once to determine at the time of retail sale, and from 
bulk supply, the quantity of commodity on the basis of liquid measure.  The retail measure -container serves 
as the container for the delivery of the commodit y. 
 
(b) Prepackaged measure- containers intended to be used only once to determine in advance of sale the quantity 
of a commodity (such as ice cream, ice milk, or sherbet) on the basis of liquid measure.  The prepackaged measure- container serves as the container for the delivery of the commodity, in either a wholesale or a 
retail marketing unit.  
 
A.2. Exceptions.  – This code does not apply to rigid containers used for milk, cream, or other fluid dairy products, 
which are covered by packaging requirements . 
 A.3. Additional Code Requirements.  – In addition to the requirements of this code, Measure -Containers shall 
meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 S.1. Units.  – The capacity of a measure -container shall be a multiple of  or a binary submultiple of a quart or a 
liter, and the measure shall not be subdivided.  However, for prepackaged measure -containers, any capacity less than 
¼ L or ½  liq pt shall be permitted.  
(Amended 1979)  
 
S.2. Capacity Point.  – The capacity of a measu re-container shall be sharply defined by:  
 
(a) the top edge;  
 
(b) a line near the top edge; or  
 
(c) the horizontal cross -sectional plane established by the bottom surface of the removable lid or cap when 
seated in the container.  
 S.3. Shape.  – A measure- container shall be designed as some suitable geometrical shape, and its capacity shall be 
determined without distortion from its normal assembled shape.  
 
S.4. Marking.  
 
S.4.1.  Capacity Point.  – If the capacity point of a measure- container is d efined by a line, the container 
shall be marked conspicuously on its side with a suitable statement clearly identifying this line as the capacity 
point.  
 
S.4.2.  Capacity Statement.  – A measure -container shall be clearly and conspicuously marked with a 
statement of its capacity in terms of one of the units prescribed in Section S.1. Units.  
 4.43.  Measure- Containers  Handbook 44 –  20152016  
Markup Copy 
Agency No. 209.02  
 N. Notes  
 
N.1. Test Liquid.  – Water shall be used as the test liquid for a measure -container.  
 
N.2. Preparation of Container for Test.  
 
N.2.1.  General.  – Before an actual test is begun, a measure -container shall, if necessary, be so restrained 
that it will maintain its normal assembled shape and that its sides will not bulge when it is filled with water.  
 
N.2.2.  Restraining Form for Test.  
 
N.2.2.1.  For R ectangular Containers of One Liter, One Quarter Less. – Bulging of the sides of a 
rectangular measure -container of 1  L (1 qt) capacity or less may be controlled by holding against each side 
of the container, with a cord, rubber bands, or tape, a metal plate or a piece of heavy cardboard slightly 
smaller than the side of the container.  
(Amended 1979)  
 
N.2.2.2.  For Rectangular Prepackaged Measure- container of Two Quarts or Two Liters or 
Greater.  – A rectangular prepackaged measure- container of 2  L (2  qt) capacity or greater shall be 
supported during a test by a rigid restraining form.  This form shall restrain not less than the entire area of 
the central two -thirds of each side of the container, measured from bottom to top.  The inside width 
dimension of any side panel of the restraining form shall be 1.6 mm (1/16 in) greater than the corresponding 
outside dimension of the container.  (The outside width dimension of any side panel of the container  shall 
be established by adding to the inner side center -of-score to center -of-score dimension two thicknesses of 
the board used, and the sum thus obtained shall be rounded off to the nearest 0.4 mm (1/64 in).) 
(Amended 1979)  
 
T. Tolerances  
 
T.1. Tolerances on an Individual Measure.  – The acceptance tolerances in excess and in deficiency on an 
individual measure shall be as shown in Table 1. Acceptance Tolerances, in Excess and in Deficiency, for Measure-
Containers.  
 
T.2. Tolerance on Average Capacity.  – The average capacity on a random sample of 10 measures selected from 
a lot of 25 or more shall be equal to or greater than the nominal capacity.  
(Amended 1979)  
 
UR. User Requirements  
 UR.1.  Limitation of Use.  – The use of a measure -container with a rectangular cross section of a capacity of 2  L 
(2 qt) or greater shall be limited to the packaging, in advance of sale, of ice cream, sherbet, or other similar frozen 
desserts.  
(Amended 1979)  
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  Agency No. 209.02  
 Table 1.  
Acceptance Tolerances, in Excess and in Deficiency, for Measure- Containers  
Nominal Capacity Tolerance 
 In Excess  In Deficiency  
 milliliters  milliliters  
¼ liter or less  10 5.0 
½ liter 15 7.5 
1 liter 20 10.0 
Over 1  liter 
 Add per liter  
10 milliliters  Add per liter 
5.0 milliliters  
 fluid drams  cubic inches  fluid drams  cubic inches  
½ pint or less  3 0.6 1.5 0.3 
1 pint 4 1.0 2.0 0.5 
1 quart  6 1.4 3.0 0.7 
2 quarts  9 2.0 4.5 1.0 
3 quarts  10 2.4 5.0 1.2 
4 quarts  12 2.8 6.0 1.2 
Over 4 quarts  Add per quart  
3 fluid drams  Add per quart  
0.7 cubic inch  Add per quart  
1.5 fluid drams  Add per quart  
0.35 cubic inch  
 
  4.43.  Measure- Containers  Handbook 44 –  20152016  
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Agency No. 209.02  
  
  
  
 
 
 
 
 
 
 
 
  
 
 
 
 
 
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 Handbook 44 –  20152016   4.44.  Graduates  
  Markup Copy 
  Agency No. 209.02  
 Section 4.44.  Graduates  
 
 
A. Application  
 
A.1. General.  – This code applies to subdivided glass measures of capacity, either cylindrical or conical in shape.  
 
A.2. Additional Code Requirements.  – In addition to the requirements of this code, Graduates shall meet the 
requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Units.  – Nominal capacities, graduation ranges, values of graduated  intervals, and numbered graduations 
applicable to single -scale graduates and to the appropriate portions of double scale graduates shall be as shown in 
Table  1. Design Details for Graduates.  
 
Table 1.  
Design Details for Graduates  
Nominal  
Capacity  To be Graduated Between  Value  of 
Graduated Intervals  Number at Each 
Graduation 
Divisible by  
milliliters  milliliters  milliliters  milliliters  
5 
10 
25 
50 
100 
500 
1000  1   and  
2   and  
5   and  
10   and  
20   and  
100   and  
200   and  5 
10 
25 
50 
100 
500 
1000  ½ 
1 
5 
5 
10 
25 
50 1 
2 
5 
10 
20 
50 
100 
minims  minims  minims  minims  
60 
120 15   and  
30   and  60 
120 5 
10 10a 
20b 
fluid  drams  fluid  drams  fluid  drams  fluid  drams  
4 
8 1   and  
2   and  4 
8 ½ 
1 1 
2 
fluid  ounces  fluid ounces  fluid ounces  fluid ounces  
2 
4 
8 
16 
32 ½   and  
1   and  
2   and  
4   and  
8   and  2 
4 
8 
16 
32 ¼ 
½ 
½ 
1 
2 ½ 
1 
1 
2 
4 
a And, in addition, at the first (15 -minim) graduation.  
b And, in addition, at the first (30 -minim) graduation.  
 
S.2. Initial Interval.  – A graduate shall have an initial interval that is not subdivided, equal to not less than 
one-fifth and not more than one -fourth of the capacity of the graduate.  
 
S.3. Shape.  – A graduate of a capacity of more than 15  mL (4 fl dr) may be of either the cylindrical or circular 
conical type.  A graduate of a capacity of 15  mL (4 fl dr) or less shall be of the single -scale cylindrical type.  4.44.  Graduates   Handbook 44 –  20152016  
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Agency No. 209.02  
  
S.4. Material.  – A graduate shall be made of good -quality, thoroughly annealed, clear, transparent glass, free 
from bubbles and streaks that might affect the accuracy of measurement.  The glass shall be uniform in thickness 
and shall not be excessively thick.  
 
S.5. Dimensional Proportions.  
 
S.5.1.  On a Circular Conical Graduate.  – The inside measurement from the bottom of a circular 
conical graduate to the capacity graduation shall be not less than two times the inside diameter at the capacity 
graduation.  The inside measurement from the bottom of the graduate to the point representing one -fourth of the 
capacity shall be not less than the inside diameter at that poin t. 
 
S.5.2.  On a Cylindrical Graduate.  – The inside measurement from the bottom of a cylindrical graduate 
to the capacity graduation shall be not less than five times the inside diameter at the capacity graduation.  
 
S.6. Base.  – The base of the graduate shall be perpendicular to the vertical axis of the graduate.  The diameter of 
the base shall be of such size that the empty graduate will remain standing on an inclined surface of 25  %, or 
approximately 15 degrees, from the horizontal.  
 
S.7. Design of Graduat ions.  
 
S.7.1.  General.  – Graduations shall be perpendicular to the vertical axis of the graduate and parallel to 
each other.  Graduations shall be continuous, of uniform thickness not greater than 0.4  mm (0.015 in), clearly 
visible, permanent, and indelible under normal conditions of use.  
(Amended 1977)  
 
S.7.2.  On a Single -Scale Graduate.  – On a single -scale graduate, the main graduations shall completely 
encircle the graduate and subordinate graduations shall extend at least one- half the distance around the graduate.  
 
S.7.3.  On a Double -Scale or a Duplex Graduate.  – On a double -scale or duplex graduate, there shall 
be a clear space between the ends of the main graduations on the two scales, and this space shall be 
approximately 90 degrees from the lip of the graduate and shall conform to the requirements of Table 2. Clear 
Space Between Ends of Main Graduations on Double Scale Graduates.  
 
Table 2.  
Clear Space Between Ends of Main Graduations on Double Scale Graduates  
Inside Diameter of Graduate at the Grad uations  
(inches ) Clear Space Between Ends of Main Graduations  
(inch) 
Less than 1.5  1/8 to ¼ 
1.5 to 3, inclusive  ¼ to ½  
Over 3  3/8 to 5/8 
 
S.8. Basis of Graduation.  – A graduate shall be graduated “to deliver” when the temperature of the graduate is 
20 °C (68  °F), and shall be marked accordingly in a permanent and conspicuous manner.  
 S.9. Marking Requirements.  – Each main graduation shall be marked to show its value.  Intermediate 
graduations shall not be marked.  Value figures shall be uniformly pos itioned either directly upon or immediately 
above the graduations to which they refer.  Figures placed upon graduations shall be set in from the ends of the graduations a sufficient distance to allow the ends of the graduations to be used in making a setting.  
 Handbook 44 –  20152016   4.44.  Graduates  
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  Agency No. 209.02  
 N. Notes  
 
N.1. Test Liquid.  – Water shall be used as the test liquid for graduates.  
 
N.2. Temperature Control.  – During the test of a graduate, appropriate precautions shall be exercised to reduce 
any detrimental temperature effects to the practicable minimum.  
 
T. Tolerances  
 
T.1. – Maintenance and acceptance tolerances in excess and in deficiency shall be as shown in Table 3. Maintenance 
and Acceptance Tolerances, in Excess and Deficiency, for Graduates for graduates that are graduated “to contain” or  
“to deliver.”  (The tolerance to be applied at any graduation is determined by the inside diameter of the graduate at the graduation in question.)  
 
Table 3.  
Maintenance and Acceptance Tolerances, in Excess and  
in Deficiency, for Graduates  
Inside Diameter of  
Graduate  
Tolerance Inside Diameter of 
Graduate  
Tolerance 
From  To But Not 
Including  From  To But Not  
Including  
millimeters  milliliters  inches  minims  
0 
16 
21 
26 
31 
36 
41 
46 
51 
56 
61 
66 
71 
76 
81 
86 
91 
96 16 
21 
26 
31 
36 
41 
46 
51 
56 
61 
66 
71 
76 
81 
86 
91 
96 
101 0.1 
0.2 
0.4 
0.6 
0.8 
1.1 
1.4 
1.8 
2.2 
2.8 
3.4 
4.1 
4.8 
5.6 
6.4 
7.2 
8.1 
9.0        0 
          9/16 
         13/16 
       11/16 
       15/16 
       19/16 
       113/16 
       21/16 
       25/16 
       29/16 
       213/16 
       31/16 
       35/16 
       39/16 
       33/16    9/16 
    13/16 
       11/16 
       15/16 
       19/16 
       113/16 
       21/16 
       25/16 
       29/16 
       213/16 
       31/16 
       35/16 
       39/16 
       313/16 
       41/16 2 
3 
6 
10 
15 
20 
30 
40 
50 
65 
80 
95 
110 
130 
150 
 
(Amended 1974)  
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 Handbook 44 –  20152016   4.45.  Dry Measures  
  Markup Copy 
  Agency No. 209.02  
 
 Section 4.45.  Dry Measures  
 
 
A. Application  
 
A.1. General.  – This code applies to rigid measures of capacity designed for general and repeated use in the 
measurement of solids, including the capacities of ½  bu or more.  
 
A.2. Exceptions.  
 
(a) This code does not apply to “standard containers” used for the measurement of fruits and vegetables and as 
shipping containers thereof.  
 
(b) This code does not apply to berry baskets and boxes.  (Also see Section  4.46. Code for Berry Baskets and 
Boxes.)  
  (Added 1976)  
 A.3. Additional Code Requirements.  – In addition to the requirements of this code, Dry Measures shall meet the 
requirements of Section  1.10. General Code.  
 
S. Specifications  
 S.1. Units.  – The capacity of a measure shall be 1  bu, a multiple of the bushel, or a binary submultiple  of the 
bushel, and the measure shall not be subdivided or double -ended.  
 S.2. Material.  – A dry measure shall be made of any suitable material that will retain its shape during normal 
usage.  
 S.3. Shape.  – A measure, other than a basket, of a capacity of ½  bu or less, shall be cylindrical or conical in shape.  
The top diameter shall in no case be less than the appropriate minimum diameter shown in Table 1. Minimum Top 
Diameters for Dry Measure other than B askets.  The bottom of a measure, other than a basket, shall be perpendicular 
to the vertical axis of the measure and shall be flat, except that a metal bottom may be slightly corrugated.  The 
bottom of a measure shall not be adjustable  or movable.  
 
Table 1. 
Minimum Top Diameters for Dry Measures other than Baskets  
Nominal Capacity Minimum Top Diameter Inches  
1 pint 4     
  1 quart  53/8 
    2 quarts  65/8 
 ½ peck  8½ 
  1 peck                                           107/8 
   ½ bushel                                           13¾  
 
S.3.1.  Conical Dry Measure.  – If conical, the top diameter shall exceed the bottom diameter by not 
more than 10  % of the bottom diameter.  4.45.  Dry Measures  Handbook 44 –  20152016  
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Agency No. 209.02  
  
S.4. Capacity Point.  – The capacity of a measure shall be determined by the top edge of the measure.  
 
S.5. Top Reinforcement.  – The top edge of a measure shall be reinforced.  On a wooden measure other than a 
basket, of a capacity of 1  qt or more, this reinforcement shall be in the form of a firmly attached metal band.  
 
S.6. Marking Requirements.  – A measure shall be conspicuous ly marked on its side with a statement of its 
capacity.  If the capacity is stated in terms of the pint or quart, the word “Dry” shall be included.  The capacity statement shall be in letters of the following dimensions:  
 
(a) At least ½  in high and ¼  in wi de on a measure of any capacity between ½  pt and 1 pk. 
 
(b) At least 1  in high and ½  in wide on a measure of a capacity of ½  bu or more.  
 
(c) On a measure of a capacity of ¼  pt or less, the statement shall be as prominent as practicable, considering 
the si ze and design of such measure.  
 
N. Notes  
 
N.1. Testing Medium.  
 
N.1.1.  Watertight Dry Measures.  – Water shall be used as the testing medium for watertight dry 
measures.  
 
N.1.2.  Non-Watertight Dry Measures.  – A dry measure shall be tested either volumetrically using 
rapeseed as a testing medium or geometrically through inside measurement and calculation.  
(Amended 1988)  
 
T. Tolerances  
 
T.1. – Maintenance tolerances in excess and in deficiency shall be as show n in Table  2. Maintenance Tolerances, in 
Excess and in Deficiency, for Dry Measure.  Acceptance tolerances shall be one- half the maintenance tolerances.  
 
Table 2.  
Maintenance Tolerances, in Excess and in Deficiency, for Dry Measures  
Nominal Capacity Tolerance 
In Excess  
Cubic Inches  In Deficiency  
Cubic Inches  
1/32 pint or less  0.1 0.05 
1/16 pint 0.15 0.1 
1/8 pint 0.25 0.15 
¼ pint 0.5 0.3 
½ pint 1.0 0.5 
1 pint 2.0 1.0 
1 quart  3.0 1.5 Handbook 44 –  20152016   4.45.  Dry Measures  
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  Agency No. 209.02  
 
 Table 2.  
Maintenance Tolerances, in Excess and in Deficiency, for Dry Measures  
Nominal Capacity Tolerance 
In Excess  
Cubic Inches  In Deficiency  
Cubic Inches  
2 quarts  5.0 2.5 
½ peck  10.0 5.0 
1 peck  16.0 8.0 
½ bushel  30.0 15.0 
1 bushel  50.0 25.0 
 
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  Handbook 44 –  20152016   4.46.  Berry Baskets and Boxes  
  Markup Copy 
  Agency No. 209.02  
 Section 4.46.  Berry Baskets and Boxes  
 
 
A. Application  
 
A.1. General.  – This code applies to baskets and boxes for berries and small fruits in capacities of 1  dry quart and 
less. 
 A.2. Additional Code Requirements.  – In addition to the requirements of this code, berry baskets and boxes shall 
meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Units.  – The capacity of a berry basket or box shall be ½  dry pint, 1  dry pint, or 1 dry quart.  
 
S.2. Materials.  – A berry basket or box shall be made of any suitable materials that will retain its shape during 
normal filling, storage, and handling.  
 
S.3. Capacity Point.  – The capacity of a berry basket or box shall be determined by its top edges.  
 
N. Notes  
 N.1. Method of Test.  – A berry basket or box may be tested either volumetrically, using rape seed as the testing 
medium, or geometrically through accurate inside dimension measurement and calculation.  
 
T. Tolerances  
 T.1. Tolerances on Individual Measures.  – Maintenance and acceptance tolerances in excess and deficiency on 
an individual measure shall be as shown in Table  1. Maintenance and Acceptance Tolerances in Excess and in 
Deficiency.  
 
T.2. Tolerances on Average Capacity.  – The average capacit y on a random sample of 10 measures selected from 
a lot of 25 or more shall be equal to or greater than the nominal capacity.  
(Amended 1979)  
 
Table 1.  
Maintenance and Acceptance Tolerances in Excess and in Deficiency  
Nominal Capacity Tolerance 
In Excess  
Cubic Inches  In Deficiency  
Cubic Inches  
½ pint  1 0.5 
1 pint  2 1.0 
1 quart  3 1.5 
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 Handbook 44 –  20152016   5.50.  Fabric -Measuring Devices  
  Markup Copy 
  Agency No. 209.02  
 Section 5.50.  Fabric -Measuring Devices 
 
 
A. Application  
 
A.1. General.  – This code applies only to mechanisms and machines designed to indicate automatically  (with or 
without value -computing capabilities) the length of fabric passed through the measuring elements.  
 A.2. Devices Used to Measure Other Similar Material in Sheet, Roll, or Bolt Form.  – Insofar as they are 
clearly appropriate, the requirements and p rovisions of this code apply also to devices designed for the commercial 
measurement of other material similar to fabrics, in sheet, roll, or bolt form.  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, Fabric -Measuring De vices 
shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Units.  – A fabric -measuring device shall indicate lengths as follows:   
(a) For devices indicating in metric units, lengths shall be indicated in terms of 5  cm; 10  cm; 25 cm; or 50 cm 
and meters.  
 In addition, lengths may be indicated in terms of any or all of the following subdivisions:  millimeters and centimeters.  
(b) For devices indicating in U.S. customary units, lengths shall be indicated in terms of 
1/8 yd; ¼  yd; or ½  yd; 
and yards.  
 In addition, lengths may be indicated in terms of any or all of the following subdivisions:  1/8 yd; 1/16 yd; 
inches and feet.  
Digital indicators may indicate values in decimal fractions.  
(Amended 1977)  
 
S.2. Design of Indicating Elements.  
 
S.2.1.  Graduations.  
 
S.2.1.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 
S.2.1.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the width of main graduations shall be not more than 50  % greater than the width of subordinate gra duations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 S.2.1.3.  Clear Interval between Graduations.  – The clear interval between graduations shall be at least 
6 mm for cm graduations (¼  in for 
1/8 yd graduations), and 3 mm for 20 cm graduations (1/8 in for 1  in 
graduations).  
 
S.2.2.  Indicator.  
 
S.2.2.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 5.50.  Fabric -Measuring Devices   Handbook 44 –  20152016  
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 S.2.2.2.  Length.  – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end of the indicator and the ends of the gradua tions, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 S.2.2.3.  Width.  – The index of an indicator shall not be wider than the narrowest graduations with 
which it is used, and shall in no case exceed 0.4  mm (0.015 in). 
 
S.2.2.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.2.2.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
S.2.3.  Money -Value Computations . 
 
S.2.3.1.  Full-Computing Type.  – In this type, the money value at  each of a series of unit prices shall be 
computed automatically for every length within the range of measurement of the fabric- measuring device.  
Value graduations shall be provided and shall be accurately positioned.  The value of each graduated interval shall be 1  cent at all prices per yard of 30  cents and less, and shall not exceed 2  cents at higher 
prices per yard.  Five- cent intervals may be represented in the two -cent range by special graduations, but 
these shall not be positioned in the clear intervals between graduations  of the regular series.  
 S.2.3.2.  Limited -Computing Type.  – In this type, the money value at each of a series of unit prices 
shall be computed automatically only for lengths corresponding to a definite series of length graduations.  
There shall be no value graduations .  At no position that the chart can assume shall two value figures at the 
same price per yard be completely and clearly exposed to view at one time.  Money values shown shall be 
mathematically accurate, except that a fraction of less than ½  cent shall be dropped and the next higher cent 
shall be shown in the case of a fraction of ½  cent or more.  One of the following requirements shall be met:  
 
(a) Ther e shall be a money -value computation for each length graduation within the range of 
measurement of the device.  
 
(b) No money -value computation shall be exposed to view except at such times as the device shows a 
length indication for which a corresponding s eries of value indications is computed.  
 
(c) Each column or row of money -value computations shall be marked to show the length to which 
the computations correspond, the device shall be marked to show the character and limitations of the computations, and there shall be computations corresponding to at least 10  cm (
1/8 yd) 
throughout the range of measurement of the device.  
 
S.2.4.  Return to Zero.  – Primary indicating elements shall be readily returnable to a definite zero 
indication.  Means shall be provided  to prevent the return of the indicating elements beyond their correct zero 
positions.  
 
S.3. Marking Requirements.  – If a device will not accurately measure all fabrics, it shall be marked to indicate 
clearly its limitations.  
 S.4. Design Accuracy.  – Indications of length and money value shall be accurate whether the values of the 
indications are being increased or decreased.  
 
N. Notes  
 
N.1. Testing Medium.  – A fabric -measuring device shall be tested with a suitable testing tape approximately 
7.62 cm (3  in) wide and with a graduated length of at least 11  m (12  yd), made from such material and having such 
surface finish as to provide dimensional stability and reduce slippage to the practicable minimum.  
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 T. Tolerances  
 
T.1. Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table 1. Maintenance and 
Acceptance Tolerances for Fabric- Measuring Devices.  
 
Table 1.  
Maintenance and Acceptance Tolerances for Fabric -Measuring Devices  
Indication of  
Device 
(yards)  Maintenance Tolerance Acceptance Tolerance 
On Under -
registration  
(inches)  On Over -
registration  
(inches)  On Under -
registration  
(inches)  On Over -
registration  
(inches)  
2 or less  3/8 ¼ ¼ 1/8 
3 3/8 5/16 ¼ 5/32 
4 ½ 5/16 ¼ 5/32 
5 5/8 3/8 5/16 3/16 
6 ¾ 3/8 3/8 3/16 
7 and 8  1 ½ ½ ¼ 
9 1¼ 5/8 5/8 5/16 
10 and 11  1½ ¾ ¾ 3/8 
12 and 13  1¾ 7/8 7/8 7/16 
14 and 15  2 1 1 ½ 
Over 15  Add 1/8 inch 
per indicated yard  Add 1/16 inch 
per indicated yard  Add 1/16 inch 
per indicated yard  Add 1/32 inch 
per indicated yard  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Installation.  – A fabric -measuring device shall be securely supported and firmly fixed in position.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Limitation of Use.  – A fabric -measuring device shall be used to measure only those fabrics that it 
was designed to measure, and in no case shall it be used to measure a fabric that a marking on the device 
indicates should not be measured.  
 UR.2.2.  Return of Indicating Elements to Zero.  – The primary indicating elements shall be ret urned to 
zero before each measurement.  
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 Handbook 44 –  20152016   5.51.  Wire - and Cordage -Measuring Devices  
  Markup Copy 
  Agency No. 209.02  
 Section 5.51.  Wire- and Cordage -Measuring Devices  
 
 
A. Application  
 
A.1. General. – This code applies to mechanisms and machines designed to indicate automatically the length of 
cordage, rope, wire, cable, or similar flexible material passed through the measuring elements.  
 A.2. Additional Code Requirements . – In addition to the requirements of this code, Wire - and Cordage -
Measuring Devices shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Unit s. – A wire - or cordage -measuring device shall indicate lengths in terms of feet, yards, or meters, or 
combinations of units of the same measurement system, and shall have minimum increments with values that do not 
exceed the equivalent of 0.1  meter or 0.1  yard.  
(Amended 1989)  
 
S.2. Design of Indicating Elements.  
 
S.2.1.  Graduations.  
 
S.2.1.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
  
S.2.1.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the width of main graduations shall be 
not more than 50  % greater than the width of subordinate gra duations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in), nor more than 1.0  mm (0.04  in), in width.  
 S.2.1.3.  Clear Interval between Graduations.  – The clear interval between graduations shall be at least 
as wide as the widest graduation, and  in no case less than 0.8  mm (0.03  in). 
 
S.2.2.  Indicator.  
 
S.2.2.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 
S.2.2.2.  Lengt h. – The index of an indicator shall reach to the finest graduations with which it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 S.2.2.3.  Width.  – The index of an indicator shall not be wider than the narrowest graduations with 
which it is used, and shall in no case exceed 0.4  mm (0.015 in). 
 S.2.2.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 S.2.2.5.  Parallax.  – Parallax effects shall be reduced to the practicable minimum.  
 
S.2.3.  Zero Indication.  – Primary indicating elements shall be readily returnable to a definite zero 
indication.  
 5.51. Wire - and Cordage -Measuring Devices   Handbook 44 –  20152016  
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 S.3. Design of Measuring Elements.  
 
S.3.1.  Sensitiveness.  – If the most sensitive element of the indicating system utilizes an indicator and 
graduations, the relativ e movement of these parts corresponding to a measurement of 30  cm (1  ft) shall be not 
less than 6  mm (¼  in). 
 
S.3.2.  Slippage.  – The measuring elements of a wire-  or cordage -measuring device shall be so designed 
and constructed as to reduce to the practicable minimum any slippage of material being measured and any lost 
motion in the measuring mechanism.  
 
S.3.3.  Accessibility.  – A wire - or cordage -measuring device shall be so constructed that the measuring 
elements are readily visible and accessible, without  disassembly of any supporting frame or section of the main 
body, for purposes of cleaning or removing any foreign matter carried into the mechanism by the material being 
measured.  
 
S.4.  Marking Requirements.  
 
S.4.1.  Limitation of Use.  – If a device will measure accurately only certain configurations, diameters, 
types, or varieties of materials, or with certain accessory equipment, all limitations shall be clearly and 
permanently stated on the device.  
 
S.4.2.  Operating Instructions.  – Any necessary operating instructions shall be clearly stated on the 
device.  
 
S.4.3.  Indications.  – Indicating elements shall be identified by suitable words or legends so that the 
values of the indications will be unmistakable.  
 
S.5.  Design Accuracy.  – Indications of length shall be accurate whether the values of the indications are being 
increased or decreased.  
 
N. Notes  
 
N.1.  Testing Medium.  – Wherever feasible, a wire-  or cordage -measuring device shall be tested with a steel tape 
not less than 10  mm (3/8 in) in width and at least 15  m (50  ft) in length.  When a device cannot be tested in this 
manner because of the design of the device, it shall be tested with a dimensionally stable material appropriately 
marked and compared at frequent periodic int ervals with a steel tape in order to assure that any marked interval is 
not in error by more than ⅓ of the tolerance of the device at that particular interval.  
(Amended 1981)  
 
N.2.  Minimum Test.  – Tests shall be conducted at a minimum initial increment of  5 m (20  ft) and appropriate 
increments up to at least 15  m (50  ft). 
 
T.  Tolerances  
 
T.1.  Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table 1. Maintenance and 
Acceptance Tolerances for Wire-  and Cordage -Measuring Devices.  
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  Agency No. 209.02  
  
 
UR.  User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Installation.  – A wire - or cordage -measuring device shall be securely supported and firmly fixed in 
position.  
 
UR.2.  Use Requirements.  
 
UR.2.1.  Limitation of Use.  – A wire - or cordage -measuring device shall be used to measure only those 
materials that it was designed to measure, and in no case shall it be used to measure a material that a marking on 
the device indicates should not be measured.  
 
UR.2.2.  Return to Zero.  – The primary indicating elements of a wire - or cordage -measuring device shall be 
returned to zero before each measurement.  
 
UR.2.3.  Operation of Device.  – A wire- or cordage -measuring device shall not be operated in such a manner 
as to cause slippage or inaccurate measurement.  
 UR.2.4.  Cleanliness.  – The measuring elements of a wire-  or cordage -measuring device shall be kept clean 
to prevent buildup of dirt and foreign material that would adversely affect the measuring capability of the 
device.  
   Table 1.  
Maintenance and Acceptance Tolerances for Wire - and Cordage -Measuring Devices  
Indication of Device  
(feet)  Acceptance and Maintenance Tolerances  
On Underregistration  
(inches)  On Overregistration  
(inches)  
20 
Over 20 to 30  
Over 30 to 40  
Over 40 to 50  
Over 50    6 
  8 
10 
12 
Add 2 inches per indicated 10  feet 3 
4 
5 
6 
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 Handbook 44 –  20152016   5.52.  Linear Measures  
  Markup Copy 
  Agency No. 209.02  
 
 Section 5.52.  Linear Measures  
 
 
A. Application  
 
A.1. General.  – This code applies to any linear measure or measure of length, whether flexible or inflexible, 
permanently installed or portable.  
 A.2. Additional Code Requirements.  – In addition to the requirements of this code, Linear Measures shall meet 
the requireme nts of Section  1.10. General Code.  
 
S. Specifications  
 
S.1.M. Units.  – A linear measure may be in total length, and the total length may be subdivided in any or all of the 
following:  
 
(a) centimeters and tenths of the centimeter;  
 
(b) meters; and  
 
(c) multiples of meters.  
 An one -meter measure may be graduated, in addition, to show 0.1  m and multiples of 0.1 m subdivisions.  
 
S.1. Units.  – A linear measure may be in total length, and the total length may be subdivided in any or all of the 
following:  
 
(a) inches and binary submultiples of the inch;  
 
(b) feet; 
 
(c) yards and multiples of yards.  
 A 1-yard measure may be graduated, in addition, to show ⅓  yd and ⅔  yd subdivisions.  A flexible tape may be 
graduated in tenths or hundredths of a foot, or both ten ths and hundredths of a foot.  (Any other subdivisions are 
allowable only on measures of special purposes and when required for such purposes.)  
 
S.2. Material.  
 
S.2.1.  Flexible Tape.  – A flexible tape shall be made of metal.  
 
S.2.2.  End Measure.  – If an end measure is made of material softer than brass, the ends of the measure 
shall be protected by brass (or other metal at least equally hard) securely attached.  
 
S.3. Finish.  – Measures shall be smoothly finished.  
 
S.4. Design.  
 
S.4.1.  Rigid Measu re. – A rigid measure shall be straight.  
 
S.4.2.  Folding Measure.  – A folding measure shall open to a definite stop, and when so opened shall be 
straight.  
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 S.5. Graduations.  
 
S.5.1.  General.  – Graduations shall be perpendicular to the edge of the measure.  
 
S.5.2.  Width.  – The width of the graduations on any measure shall not exceed one -half the width of the 
smallest graduated interval on the measure, and in no case shall be wider than 0.75  mm (0.03  in). 
(Amended 1982)  
 
T. Tolerances  
 
T.1. For Measures Except Metal Tapes.  – Maintenance tolerances in excess and in deficiency for measures 
except metal tapes shall be as shown in Table 1. Maintenance Tolerances, in Excess and in Deficiency, for Linear 
Measures Except Metal Tapes.  Acceptance tolerances shall be one -half the maintenance tolerances.  
 
Table 1.  
Maintenance Tolerances, in Excess and in Deficiency, for Linear Measures Except Metal Tapes  
Nominal Interval from Zero  Tolerance 
Feet Inch  
½ or less  
1 
2 
3 
4 
5 
6 1/64 
1/32 
1/16 
3/32 
1/8 
5/32 
3/16 
 
T.2. For Metal Tapes.  – Maintenance and acceptance tolerances in excess and in deficiency for metal tapes shall 
be as shown in Table  2. Maintenance and Acceptance Tolerances, in Excess and in Deficiency, for Metal Tapes.  
Tapes of 10 m (25  ft) or over shall be tested at a tension resulting from a load of 5  kg (10 lb).  Tapes less than 10  m 
(25 ft) shall be tested at a tension resulting from a load of 2.5  kg (5  lb).  However, flexible metal tapes  of 10 m 
(25 ft) or less that are not normally used under tension shall be tested with no tension applied.  All tapes shall be 
supported throughout on a horizontal flat surface whenever tested.  
(Amended 1972)  
 
Table 2.  
Maintenance and Acceptance Tolerances, in Excess and in Deficiency, for Metal Tapes  
Nominal Interval from Zero  Tolerance 
Feet Inch  
6 or less  
7 to 30, inclusive  
31 to 55, inclusive  
56 to 80, inclusive  
81 to 100, inclusive  1/32 
1/16 
1/8 
3/16 
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 Section 5.53.  Odometers  
 
 
A. Application  
 
A.1. General.  – This code applies to odometers that are used or are to be used to determine the charges for rent or 
hire of passenger vehicles and trucks and buses.  (When official examinations are undertaken on odometers that 
form the basis for the payment of fees or taxes to, or the preparation of reports for, governmental agencies, and in similar cases, the requirements of this code shall be applied insofar as they are applicable and appropriate to the 
conditions of such special uses.)  
(Amended 1977)  
 
A.2. Exceptions . – This code does not apply to taximeters (for which see Section 5.54. Code for Taximeters).  
(Amended 1977)  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, Odometers shall meet the 
requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating Elements.  
 
S.1.1.  General.  – The primary indicating element of an odometer may be:  
 
(a) the distance -traveled portion of the “speedometer” assembly of a motor vehicle;  
 
(b) a special cable- driven distance -indicating device; or  
 (c) a hub odometer attached to the hub of a wheel on a motor vehicle.  
(Amended 1977)  
 
S.1.2.  Units.  – An odometer shall indicate in terms of miles or kilometers.  
(Amended 1977)  
 S.1.3.  Minimum Indicated Value.  – The value of the int erval of indicated distance shall be:  
 
(a) for odometers indicating in kilometers, 0.1 kilometer km; or 
 
(b) for odometers indicating in miles, 0.1  milemi. 
(Amended 1977)  
 
S.1.4.  Advancement of Indicating Elements.  – The most sensitive indicating elements of an odometer 
may advance continuously or intermittently; all other elements shall advance intermittently.  Except when the 
indications are being returned to zero, the indications of an installed odometer shall be  susceptible to 
advancement only by the rotation of the vehicle wheel or wheels.  
(Amended 1977)  
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 S.1.5.  Readability.  – Distance figures and their background shall be of sharply contrasting colors.  
Figures indicating tenth units shall be differentiated from other figures with different colors, or with a decimal point, or by other equally effective means.  Except during the period of advance of any decade to the next 
higher indication, only one figure in each decade shall be exposed to view.  Any protective covering intended to 
be transparent shall be in such condition that it can be made transparent by ordinary cleaning of its exposed 
surface.  
(Amended 1977)  
 S.1.6.  Digital Indications and Representation.  – Digital indicating odometers (discontinuous 
registration) shall “round off” indications to the nearest minimum division or truncate indications to the lower  
minimum division . 
(Added 1990)  
 
N. Notes  
 
N.1. Testing Procedures.  
 
N.1.1.  Test Methods.  – To determine compliance with distance tolerances, a distance test of an odometer 
shall be conducted using one or more of the following test methods:  
 
(a) Road Test. –  A road test consists of driving the vehicle over a precisely measured road course.  
 
(b) Fifth -Wheel Test. –  A fifth -wheel test consists of driving the vehicle over any reasonable road course 
and determining the distance actually  traveled through the use of a mech anism known as a “fifth 
wheel” that is attached to the vehicle and that independently measures and indicates the distance.  
 
(c) Simulated -Road Test. –  A simulated -road test consists of determining the distance traveled by use of a 
roller device, or by comp utation from rolling circumference and wheel -turn data.  
(Amended 1977)  
 N.1.2.  Test Runs.  – Not less than two test runs shall be conducted.  Acceleration and deceleration shall 
be carefully controlled to avoid spinning or skidding the wheels.  
(Amended 1977)  
 
N.1.2.1.  For Devices Indicating in Miles.  – The test runs shall be 2  mi in length, shall start from, and 
finish at, a dead stop with a minimum of 80 % of the run between 30 mi/h and 45  mi/h. 
(Added 1977)  
 
N.1.2.2.  For Devices Indicating in Kilometers.  – The test runs shall be 3  km in length, shall start from, 
and finish at, a dead stop with a minimum of 80 % of the run between 50  km/h and 75 km/h.  
(Added 1977)  
 
N.1.3.  Test Conditions.  
 
N.1.3.1.  Tire Stabilization.  – Road tests or fifth -wheel tests shal l be preceded by a run of at least 8  km 
or 5 mi, for the purpose of stabilizing tire pressures.  Simulated road tests on a roller device shall be made 
at stable tire pressures.  
(Amended 1977)  
 
N.1.3.2.  Tire Pressure.  – At the completion of the test run or runs, the tires of the vehicle under test 
shall be checked to determine that the tire pressure is that operating tire pressure posted in the vehicle.  If 
not, the tire pressure should be adjusted to the posted tire pressure and further tests may be conduct ed to 
determine the operating characteristics of the odometer.  
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N.1.3.3.  Vehicle Loading.  
 
(a) Passenger Load.  – During the distance test of an odometer, the vehicle may carry two persons.  
 
(b) Truck Cargo Load.  – Truck odometers shall be tested by one of the following methods:  
 
(1) the truck is loaded with one -half of the maximum cargo load; or  
 
(2) unloaded  if unloaded test tolerances are applied.  
(Amended 1977 and 1987)  
 
T. Tolerances  
 
T.1. To Underregistration  and to Overregistration.  – The tolerances hereinafter prescribed shall be applied to 
errors of underregistration  and errors of overregistration . 
 
T.2. Tolerance Values.  – Except for unloaded trucks, maintenance and acceptance tolerances o n odometers shall 
be 4 % of the interval under test.  
(Amended 1977and 1987)  
 
T.2.1.  Tolerances for Unloaded Trucks.  – Maintenance and acceptance tolerances on truck odometers 
shall be 5  % for underregistration  and 3  % for overregistration  of the interval u nder test.  
(Added 1987)  
 
UR.  User Requirements  
 UR.1.  Inflation of Vehicle Tires.  – The operational tire pressure of passenger vehicle and truck tires shall be 
posted in the vehicle and tires shall be maintained at the posted pressure.  
(Amended 1977)  
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 Handbook 44 –  20152016   5.54.  Taximeters  
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 Section 5.54.  Taximeters  
 
 
A. Application  
 
A.1. General.  – This code applies to taximeters; that is, to devices that automatically calculates at a predetermined 
rate or rates and indicate the charge for hire of a vehicle.  
 A.2. Exceptions.  – This code does not apply to odometers on vehicles that are rented on a distance basis (for 
which see Section  5.53. Code for Odometers).  
(Amended 1977)  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, Taximeters shall m eet the 
requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements.  
 
S.1.1.  General.  – A taximeter shall be equipped with a primary indicating element and may be equipped 
with a recording element. . 
(Amended 1988 and 2015)  
 
S.1.1.1.  Recording Elements.  – A receipt providing information as required in S.1.9. Recorded 
Representations shall be available from a taximeter or taximeter system through an integral or separate 
recording element for all transactions conducted.  
[Nonretroactive January 1, 2016]  
(Added 2015)  
 
S.1.2.  Advancement of Indicating Elements.  – Except when a taximeter is being cleared, the primary 
indicating and recording elements shall be susceptible of advancement only by the move ment of the vehicle or 
by the time mechanism.  
(Amended 1988)  
 S.1.3.  Visibility of Indications.  – The indications of fare, including extras, and the mode of operation, 
such as “time” or “hired,” shall be constantly displayed whenever the meter is in operat ion.  All indications of 
passenger interest shall be easily read from a distance of 1.2  m (4 ft) under any condition of normal operation.  
(Amended 1977, 1986, and 1988)  
 
S.1.3.1.  Minimum Height of Figures, Words, and Symbols.  – The minimum height of the fi gures used 
to indicate the fare shall be 10  mm and for extras, 8  mm.  The minimum height of the figures, words, or 
symbols used for other indications, including those used to identify or define, shall be 3.5 mm. 
(Added 1986)  
 S.1.3.2.  Lighting of Indications.  – Integral lighting shall be provided to illuminate the fare, extras, the 
rate or rate code, and the taximeter status (i.e., vacant, hired, and time off).  
[Nonretroactive as of January  1, 1989]  
(Added 1988) (Amended 1990)  
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 S.1.3.3. Passenger’s  Indications . – A supplementary indicating element installed in a taxi to provide 
information regarding the taxi service to the passenger, shall clearly display the current total of all charges 
incurred for the transaction.  The accruing total of all charges must remain clearly visible on the 
passenger’s display (unless disabled by the passenger) at all times during the transaction.  
[Nonretroactive as of January 1, 2016]  
(Added 2015)  
 
S.1.3.3.1.  Additional Information.  – Additional information shall be displayed or made available 
through a passenger’s indicating element (as described in S.1.3.3. Passenger’s Indications) and shall 
be current and reflect any charges that have accrued.  This additional information shall include:  
 
(a) an itemized account of all charges incurred including fare, extras, and other additional 
charges; and  
 
(b) the rate(s) in use at which any fare is calculated.  
 
Any additional information made available must not obscure the accruing total of charges for  the taxi 
service.  This additional information may be made accessible through clearly identified operational 
controls (e.g., keypad, button, menu, touch- screen).  
[Non retroactive as of January 1, 2016]  
(Added 2015)  
 
S.1.3.3.2.  Fare and Extras Charges.  –  The indication of fare and extras charges on a passenger’s 
indicating element shall agree with similar indications displayed on all other indicating elements in 
the system.  
[Nonretroactive as of January 1, 2016]  
(Added 2015)  
 
S.1.4.  Actuation of Fare -Indic ating Mechanism.  – When a taximeter designed to calculate fares upon 
the basis of a combination of distance traveled and time elapsed is operative with respect to fare indication, the 
fare-indicating mechanism shall be actuated by the distance mechanism wh enever the vehicle is in motion at 
such a speed that the rate of distance revenue equals or exceeds the time rate, and may be actuated by the time 
mechanism whenever the vehicle speed is less than this and when the vehicle is not in motion.  Means shall be  
provided for the vehicle operator to render the time mechanism either operative or inoperative with respect to 
the fare -indicating mechanism.  
(Amended 1977)  
 
S.1.5.  Operating Condition.  
 
S.1.5.1.  General.  – When a taximeter is cleared, the indication “Not Registering,” “Vacant,” or an 
equivalent expression shall be shown.  Whenever a taximeter is set to register charges, it shall indicate 
“Registering,” “Hired,” or an equivalent expression and the rate at which it is set shall be automatically 
indicated (Rate  1 or Rate  A, for example).  
(Amended 1988)  
 
S.1.5.2.  Time not Recording.  – When a taximeter is set for fare  registration with the time mechanism 
inoperative, it shall indicate “Time Not Recording” or an  equivalent expression.  
(Amended 1988)  
 
S.1.6.  Fare Identification.  – Fare indications shall be identified by the word “Fare” or by an equivalent 
expression.  Values shall be defined by suitable words or monetary signs.  
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 S.1.7.  Extras.  – Extras shall be indicated as a separate item and shall not be included in the fare 
indication.  They shall be identified by the word “Extras” or by an equivalent expression.  Values shall be 
defined by suitable words or monetary signs.  Means may be pro vided to totalize the fare and extras if the 
totalized amount returns to separate indications of fare and extras within 5  seconds or less.  
(Amended 1988)  
 
S.1.7.1.  Nonuse  of Extras.  – If and when taximeter extras are prohibited by legal authority or are 
discontinued by a vehicle operator, the extras mechanisms shall be rendered inoperable or the extras 
indications shall be effectively obscured by permanent means.  
 
S.1.8.  Protection of Indications.  – Indications All indications  of fare and extras shall be displayed 
through and entirely protected by glass from unauthorized alteration  or other suitable transparent material 
securely attached to the housing of the taximeter manipulation . 
(Amended 2015)  
 
S.1.9.  Recorded Representation.  – A printed receipt issued f rom a taximeter , whether through an 
integral or separate recording element, shall include as a minimum, the following  information when processed 
through the taximeter system : 
 
(a) date; 
 
(b) unique  vehicle identification number, such as the medallion number, taxi number, vehicle 
identification number (VIN ) or), permit number , or other identifying information as specified by the 
statutory authority ;* 
 
(c) start and end time of the trip;* 
 
(d) distanc e traveled, maximum increment  of 0.1 kilometer km (0.1 milemi);* 
 (e) fare in $; 
 
(f) for multi- rate taximeters, each rate at which the fare was computed and the associated fare at that 
rate;* 
 
(g) additional  charges (in $) where permitted such as extras, surcharge, telephone use, tipany surcharges, 
telecommunication charges,  and taxtaxes  shall be identified and itemized ;* and 
 
(h) total charge for service in  $ (inclusive of fare  in $ (, extras, and all additional charges) ;* 
 
(i) trip number, if available;** and 
 
(j) telephone number (or other contract information) for customer assistance.**  
 
Note:  When processed through the taximeter or taximeter system, any adjustments (in $) to the total charge for service 
including discounts, credits, and tips shall also be included on the receipt.**  
 
[Nonretroactive  as of January  1, 1989] * [Nonretroactive as of January  1, 2000]   
**[Nonretroactive  as of January  1, 2016]  
(Added 1988) (Amended 1999 and 2015)  
 
S.1.9.1.  Multiple Recorded Representations.  
 
S.1.9.1.1.  Duplicate Receipts.  – A recording element may produce a duplicate receipt for the previous 
transaction provided the information printed is identical to the original with the exception of time 5.54.  Taximeters   Handbook 44 –  20152016  
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 issued.  The duplicate receipt shall include the words “duplicate” or “copy.”  The feature to print a 
duplicate receipt shall be deactivated at the time the meter is hired for the next fare . 
[Nonretroactive  as of January  1, 2000]  
(Added 1999)  
 
S.1.10.  Non-fare Information.  – The fare and extras displays may be used to display auxiliary 
information provided the meter is in the vacant condition and such information is only displayed for10 seconds, 
or less.  If the information consists of a list of information, the  list may be displayed one item after another, 
provided that each item is displayed for 10 seconds, or less.  
[Nonretroactive  as of January  1, 2002]  
(Added 2000)  
 
S.2. Basis of Fare Calculations.  – A taximeter shall calculate fares only upon the basis of:  
 
(a) distance  traveled; 
 
(b) time elapsed; or  
 
(c) a combination of distance traveled and time elapsed.  
(Amended 1977)  
 
S.2.1.  Initial Time and Distance Intervals.  – The time and distance intervals of a taximeter shall be 
directly proportional as expressed in the following formula:  
Interval Mileage Initial Nonpercen DistaInterval Mileage Initialof ancetDis
Interval Time Initial Nonper SecondsInterval Time Initialof Seconds
        
        
−=− 
(Added 1990)  
 
S.3. Design of Operating  Control.  
 
S.3.1.  Positions of Control.  – The several positions of the operating controls shall be clearly defined and 
shall be so constructed that accidental or inadvertent changing of the operating condition of the taximeter is 
improbable.  Movement of the operating controls to an operating position immediately following movement to 
the cleared position shall be delayed enough to permit the taximeter to come to a complete rest in the cleared 
position.  
(Amended 1988)  
 S.3.2.  Flag.  – If the control for  the operating condition is a lever -arm and flag, the flag shall be at its 
highest position when the taximeter is cleared, and in this position the whole of the flag shall be above the level 
of the taximeter housing.  
 S.3.3.  Control for Extras Mechanism.  – The knob, handle, or other means provided t o actuate the 
extras mechanism shall be inoperable whenever the taximeter is cleared.  
 
S.4. Interference.  – The design of a taximeter shall be such that there will be no interference between the time 
and the distance portions of the mechanism  device at any  speed of operation.  
(Amended 1977 and 1988)  
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 S.5. Provision for Security Seals.  – Adequate provision shall be made to provide security for a taximeter.  
Security may be provided either by:  
 
(a) Affixing security seals to the taximeter and to all other com ponents required for service operation of a 
complete installation on a vehicle, so that no adjustments, alterations, or replacements affecting accuracy or 
indications of the device or the assembly can be made without mutilating the seal or seals; or  
 (b) Using a combination of security seals described in paragraph  (a) and, in the case of a component that may 
be removed from a vehicle (e.g., slide mounting the taximeter), providing a physical or electronic link 
between components affecting accuracy or indications of the device to ensure that its performance is not 
affected and operation is permitted only with those components having the same unique properties.  
 
The sealing means shall be such that it is not necessary to disassemble or remove any part of the device or of the vehicle to apply or inspect the seals.  
(Amended 1988 and 2000)  
 
S.6. Power Interruption, Electronic Taximeters.  
 
(a) After a power interruption of 3 seconds or less, the fare and extras indications shall return to the previously 
displayed indications and may be susceptible to advancement without the taximeter being cleared.  
 
(b) After a power interruption exceeding 3  seconds, the fare and extras indications shall return to the 
previously displayed indications and shall not be susceptible to  advancement until the taximeter is cleared.  
 
After restoration of power following an interruption exceeding 3 seconds, the previously displayed fare shall be 
displayed for a maximum of 1 minute at which time the fare shall automatically clear and the taxi meter shall return 
to the vacant condition. * 
[*Nonretroactive as of January  1, 2002]  
(Added 1988) (Amended 1989, 1990, and 2000)  
 S.7. Anti -Fraud Provisions, Electronic Taximeters.  – An electronic taximeter may have provisions to detect 
and eliminate distance input that is inconsistent with output of the vehicle’s distance sensor.  When a taximeter 
equipped with this feature detects input inconsistent with the distance sensor:  
 
(a) The meter shall either filter out the inconsistent distance input signals or cease to increment fare based on 
distance until the distance input signal returns to normal.  If the meter ceases to increment fare based on 
distance, the taximeter may continue to increment fare based on elapsed time;  
 
(b) The taximeter shall provide a visible or audible signal that inconsistent input signals are being detected; and  
 
(c) The taximeter shall record the occurrence in an event logger.  The event logger shall include an  event 
counter (000 to 999), the date, and the time of at least the last 1000 occurrences.  
(Added 2001)  
 
N. Notes  
 
N.1. Distance Tests.  
 
N.1.1.  Test Methods.  – To determine compliance with distance tolerances, a distance test of a taximeter 
shall be conducted utilizing one or more of the following test methods:  
 
(a) Road Test.  – A road test consists of driving the vehicle over a precisely measured road course.  
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 (b) Fifth -Wheel Test.  – A fifth -wheel test consists of driving the vehicle over any reasonable road course 
and determining the distance actually traveled through the use of a mechanism known as a “fifth wheel” that is attached to the vehicle and that ind ependently measures and indicates the distance.  
 
(c) Simulated- Road Test.  – A simulated road test consists of determining the distance traveled by use of 
a roller device, or by computation from rolling circumference and wheel -turn data.  
(Amended 1977)  
 
N.1.2.  Test Procedures.  – The distance test of a taximeter, whether a road test, a simulated -road test, or 
a fifth -wheel test, shall include at least duplicate runs of sufficient length to cover at least the third money drop 
or 1 mi, whichever is greater, and shall be at a speed approximating the average speed traveled by the vehicle in 
normal service.  In the case of metric -calibrated taximeters, the test should cover at least the third money drop 
or 2 km, whichever is greater.  
(Amended 1977)  
 
N.1.3.  Test Conditions.  
 
N.1.3.1.  Vehicle Lading.  – During the distance test of a taximeter, the vehicle shall carry two persons, or 
in the case of a simulated -road test, 70 kg or 150 lb of test weights may be substituted in lieu of the second 
person.  
 
N.1.3.2.  Tire Pressure.  – At the completion of test run or runs, the tires of the vehicle under test shall be 
checked to determine that the tire pressure is that operating tire pressure posted in the vehicle.  If not, the 
tire pressure should be adjusted to the posted t ire pressure and further tests may be conducted to determine 
the operating characteristics of the odometer taximeter . 
(Amended 1977)  
 
N.2. Time Test.  – If a taximeter is equipped with a timing device through which charges are made for time 
intervals, the ti mer shall be tested at the initial interval, four separate subsequent intervals, and an average time test 
of at least four consecutive subsequent time intervals.  
(Amended 1988)  
 
N.3. Interference Test.  – If a taximeter is equipped with a timing device thro ugh which charges are made for time 
intervals, a test shall be conducted to determine whether there is interference between the time and distance 
elements.  During the interference test, the vehicle’s operating speed shall be 3  km/h or 4 km/h, or 2 mi/h or  3 mi/h 
faster than the speed at which the basic distance rate equals the basic time rate.  The basic rate per hour divided by 
the basic rate per mile is the speed (km/h or mi/h) at which the basic time rate and basic distance rate are equal.  
(Amended 1988)  
 
T. Tolerances  
 
T.1. Tolerance Values.  
 
T.1.1.  On Distance Tests.  – Maintenance and acceptance tolerances for taximeters shall be as follows:  
 
(a) On Overregistration:  1  % of the interval under test.  
 
(b) On Underregistration:  4  % of the interval under  test, with an added tolerance of 30  m or 100 ft 
whenever the initial interval is included in the interval under test.  
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 T.1.2.  On Time Tests.  
 
T.1.2.1.  On Individual Time Intervals.  – Maintenance and acceptance tolerances on individual time 
intervals shall be as follows:  
 
(a) On Overregistration:  3  seconds per minute (5 %). 
 
(b) On Underregistration:  9  seconds per minute (15 %) on the initial interval, and 6  seconds per 
minute (10  %) on subsequent intervals.  
 T.1.2.2.  On Average Time Interval Computed After the Initial Interval.  – Except for the initial 
interval, maintenance and acceptance tolerances on the average time interval shall be as follows:  
 
(a) On Overregistration:  0.2  second per minute (0.33 %). 
 
(b) On Underregistration:  3  seconds per minu te (5 %). 
(Amended 1991)  
 
T.1.3.  On Interference Tests.  
 
T.1.3.1.  The registration of a taximeter in the “time on” position shall agree within 1  % of its 
performance in the “time off” position.  
(Added 1988)  
 
UR. User Requirements  
 
UR.1.  Inflation of Vehicle Tires.  – The operational tire pressure of passenger vehicles and truck tires shall be 
posted in the vehicle and shall be maintained at the posted pressure.  
(Amended 1977)  
 
UR.2.  Position and Illumination of Taximeter.  – A taximeter shall be so positioned and illuminated that its 
indications, operational markings, and controls of passenger interest can be conveniently read by a passenger seated in the back seat of the vehicle.  
(Amended 1985 and 1986)  
 UR.3.  Statement of Rates.  – The distance and time rates for which a taximeter is set, including the initial 
distance interval and the initial time interval, the local tax rate, and the schedule of extras when an extras indication 
is provided shall be conspicuously displayed inside the front and rear passenger compartments.  The words “Rate,” 
“Rates,” or “Rates of Fare” shall precede the rate statement.  The rate statement shall be fully informative, self -
explanatory, and readily understandable by the ordinary passenger, and shall either be of a permanent character or be protected by glass or other suitable transparent material.  
(Amended 1977, 1988, 1990, and 1999)  
 
 
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 Section 5.55.  Timing Devices  
 
 
A. Application  
 
A.1. General.  – This code applies to devices used to measure time  during which services are being dispensed 
(such as vehicle parking, laundry drying, and car washing).   This code also applies to Electric Vehicle Supply 
Equipment (EVSE) when used to assess charges for time -based services in addition to those charged for electrical 
energy.  
(Amended 2015)  
 A.2. Additional Code Requirements.  – In addition to the requirements of this code, Timing Devices shall meet 
the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements.  
 
S.1.1.1.  General.  – A timing device shall be equipped with a primary indicating element, and may also 
be equipped with a primary recording element.  A timing device incorporated into an Electric Vehicle 
Supply Equipment system for use in assessing charges for timing separate from charges for electrical 
energy shall be equipped with the capability to provide a recorded representation of the transaction through 
a built- in or separate recording element.  A readily observable in -service light or other equally effective 
means that automatically indicates when laundry driers, vacuum cleaners, and car washes are in operation 
shall be deemed an appropriate prim ary indicating element.  
(Amended 1979 and 2015)  
 
S.1.1.2.  Units.  – A timing device shall indicate and record, if the device is equipped to record, the time 
in terms of minutes for time intervals of 60  minutes or less and in hours and minutes for time intervals 
greater than 60  minutes.  
 
S.1.1.3.  Value of Smallest Unit.  – The value of the smallest unit of indicated time and recorded time, if 
the device is equipped to record, shall not exceed the equivalent of:  
 
(a) one-half hour on parking meters i ndicating time in excess of two  hours;  
 
(b) six minutes on parking meters indicating time in excess of one but not greater than two  hours; or  
 (c) five minutes on all other devices, except those equipped with an in -service light.  
(Amended 1975)  
 
S.1.1.4.  Advancement of Indicating and Recording Elements.  – Primary indicating and recording 
elements shall be susceptible to advancement only during the mechanical operation of the device, except 
that clocks may be equipped to manually reset the time.  
 
S.1.1.5.  Operation of In -Service Indicator Light.  – TheFor devices equipped with an  in--service 
indicator light, the  indicator shall be operative only during the time the device is in operation.  
(Amended 2015)  
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 and not more than two  minutes for times of one  hour or more.  Convenient means shall be provided to 
indic ate to the purchaser the unexpired time.  
(Added 1975) (Amended 1976)  
 
S.1.2.  Graduations.  
 
S.1.2.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 S.1.2.2.  Width.  – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations and the width of main graduations shall be 
not more than 50  % greater than the width of subordinate grad uations .  Graduations shall in no case be less 
than 0.2  mm (0.008 in) in width.  
 S.1.2.3.  Clear Interval Between Graduations.  – The clear interval shall be not less than 0.75  mm 
(0.03  in).  If the graduations are not parallel, the measurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 
(b) if the indicator is continuous, at the point of widest separation of the graduations.  
 
S.1.3.  Indicators.  
 
S.1.3.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 S.1.3.2.  Length.  – The index of an indicator shall reach to the finest graduations with whic h it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.3.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than:  
 
(a) the width of the widest graduation; and  
 
(b) the width of the minimum clear interval between the gradua tions.  
 
S.1.3.4.  Parallax.  – Parallax effect shall be reduced to a practicable minimum.  
 
S.1.4.  Printed Tickets Recorded Representations.  
 
S.1.4.1.  Recorded Representations, Electric Vehicle Supply Equipment (EVSE) Timing Devices. –  A 
timing device incorporated into an EVSE for use in assessing charges for timing separate from charges for 
electrical energy shall issue a recorded representation itemizing the charges for these services as defined in 
Section 3.40. Electric Vehicle Fueling Systems.  
(Adde d 2015)  
 
S.1.4.1.1.  Duplicate Receipts. –  Duplicate receipts are permissible, provided the word “duplicate” 
or “copy” is included on the receipt.  
(Added 2015)  
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 S.1.4.2.  Recorded Representations, All Other Timing Devices . – A printed ticket issued or stamped by a 
timing device shall have printed clearly thereon:  
 
(a) the time and day when the service ends and the time and day when the service begins, except that 
a self -service money -operated device that clearly displays the time of day need not record the time 
and day when the service begins; or  
 
(b) the time interval purchased, and the time and day that the service either begins or ends.  
(Added 2015)  
(Amended 1983 and 2015)  
 
S.2. Marking Requirements, Operating Instructions.  – Operating instructions shall be clearly stated on the 
device.  
 
S.3. Interference.  – The design of the EVSE shall be such that there will be no interference between the time and 
electrical energy measurement elements of the system.  
(Added 2015)  
 
S.4. Provisions for Sealing.  – Adequate provisions shall be made to provide security for the timing element.  
(Added 2015)  
 
S.5. Power Interruption.  – In the event of a power loss, the information needed to complete any transaction 
(i.e., delivery is complete and p ayment is settled) in progress at the time of the power loss (such as the quantity and 
unit price, or sales price) shall be determinable through one of the means listed below or the transaction shall be 
terminated without any charge for the electrical ener gy transfer to the vehicle:  
 
(a) at the EVSE;  
 
(b) at the console, if the console is accessible to the customer;  
 
(c) via on site Internet access; or  
 
(d) through toll -free phone access.  
 
For EVSEs in parking areas where vehicles are commonly left for extended periods, th e information needed to 
complete any transaction in progress at the time of the power loss shall be determinable through one of the above 
means for at least eight hours.  
(Added 2015)  
 
S.5.1.  Transaction Termination.  – In the event of a power loss, either:  
 
(a) the transaction shall terminate at the time of the power loss; or  
 
(b) the EVSE may continue charging without additional authorization if the EVSE is able to determine it is 
connected to the same vehicle before and after the supply power outage.  
 
In either case, there must be a clear indication on the receipt provided to the customer of the interruption, 
including the date and time of the interruption along with other information required under S.1.4.2. Recorded 
Representations, All Other Timing Devices.  
(Added 2015)  
 
S.5.2.  User Information.  – The EVSE memory, or equipment on the network supporting the EVSE, 
shall retain information on the quantity of time and the sales price totals during a power loss.  
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N. Notes  
 
N.1. Test Method.  – A timing device shall be tested with a timepiece with an error of not greater than plus or 
minus 15 seconds per 24- hour period.  In the test of timing devices with a nominal capacity of 1  hour or less, 
stopwatches with a minimum division of not greater than one -fifth second shall be used.  In the test of timing 
devices with a nominal capacity of more than one hour, the value of the minimum division on the timepiece shall be 
not greater than one  second.  Time pieces  and stopwatches shall be calibrated with standard time signals as 
described in National Institute of Standards and Technology Special Publication  432, NIST Time and Frequency 
Dissemination Services, or any superseding publication.  
(Amended 1978)  
 
N.2. Broadcast Times and Frequencies.  – Time and frequency standards are broadcast by the stations listed in 
Table  N.2. Broadcast Times and Frequencies.  
 
Table N .2.* 
Broadcast Times and Frequencies  
Station  Location,  
Latitude,  
Longitude  Frequency  
(MHz) Times  of 
Transmission  
(UTC)  
WWV  Fort Collins,  Colorado  
4041' N  
105 02' W  2.5 
5.0 
10.0 
15.0 
20.0 Continuous  
WWVH  Kauai, Hawaii  
2159' N  
159 46' W  2.5 
5.0 
10.0 
15.0 Continuous  
CHU  Ottawa, Canada  
4518' N  
7545' W  3.330  
7.335  
14.670  
14.670  Continuous  
*From NIST Special Publication  559, “Time and Frequency Users’ Manual,” 1990.  
(Added 1988)  
 
N.3. Interference Tests, EVSE.  – On an EVSE equipped with a timing device used to calculate time -based 
charges in addition to any charges assessed for electrical energy, a test shall be conducted to ensure that there is no 
interference between time and electrical energy measuring elements.  
(Added 2015)  
 
 
T. Tolerances  
 
T.1. Tolerance Values.  – Maintenance and acceptance tolerances for timing devices shall be as follows:  
 
T.1.1.  For Timing Devices Other Than Those Specified in T.1.2.  For Time Clocks and Time 
Recorders and T.1.3.  On Parki ng Meters.  – The maintenance and acceptance tolerances shall be:  
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 (a) On Overregistration:  five  seconds for any time interval of one minute or more; and  
(Amended 1986)  
 
(b) On Under registration:  six  seconds per indicated minute.  
(Amended 1975)  
 T.1.2.  For Time Clocks and Time Recorders.  – The maintenance and acceptance tolerances on over -
registration  and under registration shall be three  seconds per hour, but not to exceed one  minute per day.  
(Amended 1975)  
 
T.1.3.  On Parking Meters  and Other Timing Devices Used to Assess Charges for Parking . – The 
maintenance and acceptance tolerances are shown in Table T.1.3.  Maintenance and Acceptance Tolerances for 
Parking Meters  and Other Timing Devices Used to Assess Charges For Parking.  
(Amend ed 2015)  
 
(Amended 2015)  
 
T.2. Tests Involving Digital Indications or Representations.  – To the tolerances that would otherwise be 
applied, there shall be added an amount equal to one- half the minimum value that can be indicated or recorded.  
 
UR. User  Requirements  
 
UR.1.  Statement of Rates.  – The price in terms of money per unit or units of time for the service dispensed and 
the number of coins the device will accept and be activated by at one time, following information  shall be clearly, 
prominently, a nd conspicuously displayed. :   
 
(a) the price in terms of money per unit or units of time for the service dispensed; and  
 
(b) for a timing device other than an EVSE, the number of coins the device will accept and be activated by at 
one time.  
(Amended 1976 and 2015)  
 
UR.2.  Time Representations.  – Any time representation shall be within plus or minus two  minutes of the correct 
time in effect in the area, except on an individual clock used only for “time out”; in addition, the time indication of 
the “time -out” clock s hall be the same as or less than that of the “time -in” clock.  
(Amended 1975)  
  Table T.1.3.  
Maintenance and Acceptance Tolerances for Parking Meters and  
Other Timing Devices Used to Assess Charges for Parking  
Maintenance and Acceptance Tolerances  
Nominal Time Capacity  On Overregistration  On Underregistration  
30 minutes or less  No tolerance 10 seconds per minute,  
but not less than 2 minutes  
Over 30 minutes to and 
including 1 hour  No tolerance 5 minutes plus 4 seconds  
per minute over 30 minutes  
Over 1 hour  No tolerance 7 minutes plus 2 minutes  
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  Handbook 44 –  20152016   5.56.(a)  Grain Moisture Meters  
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 Section 5.56. (a) Grain Moisture Meters  
 
 
Section 5.56. was reorganized into two sections beginning with the 1997 Edition of NIST Handbook  44.  This 
Section, 5.56. (a), applies to all NTEP grain moisture meters.  It also applies to any grain moisture meter 
manufactured or placed into service after January  1, 1998.   
(Code reorganized and renumbered 1996)  
 
A. Application  
 
A.1. General Code.  – This code applies to grai n moisture meters, that is, devices used to indicate directly the 
moisture content of cereal grain and oil seeds.  The code consists of general requirements applicable to all moisture 
meters and specific requirements applicable only to certain types of moi sture meters.  Requirements cited for “test 
weight per bushel” indications or recorded representations are applicable only to devices incorporating an automatic 
test weight per bushel measuring feature.  
(Amended 2003)  
 A.2. Exceptions.  – This code does not  apply to devices used for in -motion measurement of grain moisture content 
or seed moisture content.  
 A.3. Type Evaluation. –  The National Type Evaluation Program (NTEP) will accept for type evaluation only 
those devices that comply with this code.  State enforcement will be based upon the effective dates identified with each requirement when specific dates are shown.  
(Added 1993)  
 A.4. Additional Code Requirements.  – In addition to the requirements of this code, 5.56. (a) Grain Moisture 
Meters shall meet the requirements of Section 1.10.  General Code.  
 
S. Specifications  
 
S.1. Design of Indicating, Recording, and Measuring Elements.  
 
S.1.1.  Digital Indications and Recording Elements.  
 
(a) Meters shall be equipped with a digital indicating element.  
 
(b) The minimum height for  the digits used to display moisture content shall be 10  mm. 
 
(c) Meters shall be equipped with a communication interface that permits interfacing with a recording 
element and transmitting the date, grain type, grain moisture results, tes t weight per volume results, 
and calibration version identification.  
 
(d) A digital indicating element shall not display, and a recording element shall not record, any moisture 
content values or test weight per volume values before the end of the measurement c ycle.  
 
(e) Moisture content results shall be displayed and recorded as percent moisture content, wet basis.  Test 
weight per bushel results shall be displayed and recorded as pounds per bushel.  Subdivisions of these 
units shall be in terms of decimal subdivisions (not fractions).  
 
(f) A meter shall not display or record any moisture content or test weight per volume values when the 
moisture content of the grain sample is beyond the operating range of the device, unless the moisture 
and test weight represen tations include a clear error indication (and recorded error message with the 
recorded representation).  
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 (g) On multi -constituent meters (e.g., meters which also measure grain protein), provision shall be made 
for displaying and recording the constituent label  (such as moisture, protein, etc.) to make it clear 
which constituent is associated with each of the displayed and recorded values.  
(Added 1995)  
(Amended 1993, 1994, 1995, 1996, and 2003)  
 
S.1.2.  Selecting or Recording Grain or Seed Type and Class.  – Provision shall be made for selecting 
and recording the type and class or multi -class group (as appropriate) of grain or seed to be measured.  The 
means to select the type and class or multi -class group  of grain or seed shall be readily visible and the type and 
class or multi -class group  of grain or seed selected shall be clearly and definitely identified.  Abbreviations for 
grain types and multi -class groups indicated on the meter must meet the minimum acceptable abbreviations 
listed in Table  S.1.2. Gra in Types and Multi -Class Groups Considered for Type Evaluation and Calibration and 
Their Minimum Acceptable Abbreviations.  
(Amended 1993, 1995, and 2007)  
 
Table S.1.2.  
 Grain Types and Multi -Class Groups Considered for Type Evaluation and Calibration and T heir 
Minimum Acceptable Abbreviations  
Grain Type  Grain Class  Minimum Acceptable Abbreviation  
Barley  All-Class Barley*  BARLEY  
Six-Rowed Barley  SRB 
Two-Rowed Barley  TRB 
Corn  --- CORN  
Grain Sorghum  --- SORG or MILO  
Oats  --- OATS  
Rice All-Class Rough  Rice*  RGHRICE  
Long Grain Rough Rice  LGRR  
Medium Grain Rough Rice  MGRR  
Small Oil Seeds  
(under consideration)  --- --- 
Soybeans  --- SOYB  
Sunflower seed (Oil)  --- SUNF  
Wheat  All-Class Wheat*  WHEAT  
Durum Wheat  DURW  
Hard Red Spring Wheat  HRSW  
Hard  Red Winter Wheat  HRWW  
Hard White Wheat  HDWW  
Soft Red Winter Wheat  SRWW  
Soft White Wheat  SWW  
Wheat Excluding Durum*  WHTEXDUR  
Note:   Grain Types marked with an asterisk (*) are “Multi -Class Calibrations.”  
[Nonretroactive as of January  1, 1998]  
(Table Added 1993) (Amended 1995, 1998, and 2007)  
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 S.1.3.  Operating Range.  – A meter shall automatically and clearly indicate when the operating range of 
the meter has been exceeded.  The operating range shall specify the following:  
 
(a) Temperature Range  of the Meter.  – The temperature range over which the meter may be 
used and still comply with the applicable requirements shall be specified.  The minimum 
temperature range shall be 10  °C to 30 °C.  No moisture value may be displayed when the 
temperature r ange is exceeded.  An appropriate message shall be displayed when the 
temperature of the meter is outside its specified operating range.  
 
(b) Temperature Range of each Grain or Seed.  – The temperature range for each grain or seed for 
which the meter is to be used shall be specified.  The minimum temperature range for each grain shall 
be 0 °C to 40 °C.  No moisture value may be displayed when the temperature range is exceeded.  An 
appropriate error message shall be displayed when the temperature of the grain  sample exceeds the 
specified temperature range for the grain.  
 
(c) Moisture Range of the Grain or Seed.  – The moisture range for each grain or seed for which the 
meter is to be used shall be specified.  Moisture and test weight per bushel values may be displayed 
when the moisture range is exceeded if accompanied by a clear indication that the moisture range has 
been exceeded.  
(Amended 2003)  
 
(d) Maximum Allowable Meter/Grain Temperature Difference.  – The maximum allowable difference 
in temperature between the meter and the sample for which an accurate moisture determination can be 
made shall be specified.  The minimum temperature difference shall be 10  °C.  No moisture value may 
be displayed when th e maximum allowable temperature difference is exceeded.  An appropriate error 
message shall be displayed when the difference in temperature between the meter and the sample 
exceeds the specified difference.  
(Added 1993) (Amended 1995)  
 
S.1.4.  Value of Smal lest Unit. –  The display shall permit moisture value determination to both 0.01  % 
and 0.1 % resolution.  The 0.1  % resolution is for commercial transactions; the 0.01  % resolution is for type 
evaluation and calibration purposes only, not for commercial pur poses.  Test weight per bushel values shall be 
determined to the nearest 0.1  pound  per bushel.  
(Amended 2003)  
 
S.1.5.  Operating Temperature.  
 
(a) Warm -up period:  When a meter is turned on it shall not display or record any usable values until the 
operating temperature necessary for accurate determination has been attained, or the meter shall bear a conspicuous statement adjacent to the indication stating that the meter shall be turned on for a time 
period specified by the manufacturer prior to use.  
 (b) A meter shall meet the requirements of T.2. Tolerances when operated in the temperature range of 
10 °C to 30 °C (50  °F to 86  °F) or within the range specified by the meter manufacturer.  
 
(c) If the manufacturer specifies a temperature range, the rang e shall be at least 20  °C (36  °F). 
(Added 1993) (Amended 1995 and 1996)  
 
S.2. Design of Grain Moisture Meters.  
 
S.2.1.  Minimum Sample Size.  – Meters shall be designed to measure the moisture content of 
representative -size grain samples.  The minimum allowable sample size used in analysis shall be 100  g or 
400 kernels or seeds, whichever is smaller.  
(Added 1993) (Amended 1995)  
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 S.2.2.  Electric Power Supply.  
 
S.2.2.1.  Power Supply, Voltage and Frequency.  
 
(a) A meter that operates using alternating curr ent must perform within the tolerances defined in 
Section  T.2. Tolerances over the line voltage range 100  V to 130 V, or 200 V to 250 V rms as 
designed, and over the frequency range of 59.5 Hz to 60.5  Hz. 
 (b) Battery -operated instruments shall not indicate or record values outside the applicable tolerance 
limits when battery power output is excessive or deficient.  
 S.2.2.2.  Power Interruption.  – A power interruption shall not cause an indicating or recording element 
to display or record any values outside the applicable tolerance limits.  
(Added 1988)  
 
S.2.3.  Level Indicating Means. –  A meter shall be equipped with a level indicator and leveling 
adjustments if its performance is changed  by an amount greater than the applicable tolerance when the meter  is 
moved from a level position to a position that is out of level in any upright direction by up to 5  % 
(approximately three degrees).  The level -indicating means shall be readable without removing any meter parts 
requiring a tool.  
(Added 1988) (Amended 1994)  
 
S.2.4.  Calibration Integrity.  
 
S.2.4.1.  Calibration Version.  – A meter must be capable of displaying either calibration constants, a 
unique calibration name, or a unique calibration version number for use in verifying that the latest version 
of the calibration is being used to make moisture content and test weight per bushel determinations.  
(Added 1993) (Amended 1995 and 2003)  
 
S.2.4.2.  Calibration Corruption.  – If calibration constants are digitally stored in an electronically 
alterable form, the meter shall be designed to make automatic checks to detect corruption  of calibration 
constants.  An error message must be displayed if calibration constants have been electronically altered.  
(Added 1993) (Amended 1995)  
 
S.2.4.3.  Calibration Transfer. –  The instrument hardware/software design and calibration procedures 
shall permit calibration development and the transfer of calibrations  between instruments of like models 
without requiring user slope or bias adjustments.  
 
[Note :  Only the manufacturer or  the manufacturer’s designated service agency may make standardization 
adjustments on moisture meters.  This does not preclude the possibility of the operator installing 
manufacturer -specified calibration constants under the instructions of the manufacture r or its designated 
service agency.]  Standardization adjustments (not to be confused with grain calibrations) are those physical adjustments or software parameters which make meters  of like type respond identically to the 
grain(s) being measured.  
[Nonretroactive  as of January  1, 1999]  
(Added 1994) (Amended 1998)  
 
S.2.5.  Provision for Sealing. – Provision shall be made for applying a security seal in a manner that 
requires the security seal to be broken, or for using other approved means of providing  security (e.g., audit trail 
available at the time of inspection as defined in Table  S.2.5. Categories of Device and Methods of Sealing) 
before any change that affects the metrological integrity of the device can be made to any mechanism.  
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 Table S.2.5.  
Categories of Device and Methods of Sealing  
Categories of Device  Methods of Sealing  
Category  1:  No remote configuration capability.  Seal by physical seal or two event counters:  one for 
calibration parameters (000 to 999) and one for 
configuration parameters (000 to 999).  If equipped 
with event counters, the device must be capable of 
displaying, or printing through the device or through 
another on -site device, the contents of the counters.  
Category  2:  Remote configuration capability, but 
access is controlled by physical hardware.  
 
A device shall clearly indicate that it is in the remote 
configuration mode and shall not be capable of 
operating in the measure  mode while enabled for 
remote configuration.  The hardware enabling access for remote 
communication must be at the device and sealed using 
a physical seal or two event counters:  one for  
calibration parameters (000 to 999) and one for 
configuration parameters  (000 to 999).  If equipped 
with event counters, the device must be capable of 
displaying, or printing through the device or through 
another on -site device, the contents of the counters.  
Category  3:  Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password).  
 
When accessed for the purpose of modifying sealable  
parameters, the device shall clearly indicate that it is 
in the configuration mode and shall not be capable of 
operating in the measuring mode.  An event logger is required in the device; it must 
include an eve nt counter (000 to 999), the parameter 
ID, the date and time of the change, and the new value of the parameter (for calibration changes consisting of 
multiple constants, the calibration version number 
may be used rather than the calibration constants).  A 
printed copy of the information must be available 
through the device or through another on- site device.  
The event logger shall have a capacity to retain 
records equal to 25 times the number of sealable  
parameters in the device, but not more than 
1000 records are required.  ( Note:  Does not require 
1000 changes to be stored for each parameter.)  
Category  3a:  No remote capability, but operator  is 
able to make changes that affect the metrological  
integrity of the device (e.g., slope, bias, etc.) in normal operation.  
 
*When accessed for the purpose of modifying sealable parameters, the device shall clearly indicate that it is 
in the configuration mode and shall not be capable of 
operating in the measuring mode.  Same as Category  3 
Category  3b:  No remote capability, but access to 
metrological  parameters is controlled through a 
software switch (e.g., password).  
 
*When accessed for the purpose of modifying sealable parameters, the device shall clearly indicate that it is 
in the configuration mode  and shall not be capable of 
operating in the measuring mode.  Same as Category  3 
[Nonretroactive  as of January  1, 1999]  
[*Nonretroactive as of January 1, 2014]  
(Amended 1998 and 2013)  
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 Note :  Zero -setting and test point adjustments are considered to affect metrological  characteristics and must be sealed.  
(Added 1993) (Amended 1995 and 1997)  
 
S.2.6.  Determination of Quantity and Temperature.  – The moisture meter system shall not require the 
operator to judge the precise volume or weight and temperature needed to make an accurate moisture 
determination.  External grinding, weighing, and temperature measurement operations are not permitted.  In 
addition, if the meter is capable of measuring test  weight per bushel, determination of sample volume and 
weight for this measurement shall be fully automatic and means shall be provided to ensure that measurements 
of test weight per volume are not allowed to be displayed or printed when an insufficient sample volume is 
available to provide an accurate measurement. [ Nonretroactive  as of January 1, 2004]  
(Added 1994) (Amended 1995 and 2003)  
 
S.3. Accessory Equipment.  – When the operating instructions for a moisture meter require accessory equipment 
separate from and external to the moisture meter, such equipment shall be appropriate and complete for the 
measurement.  
 
S.4. Operating Instructions and Use Limitations.  – The manufacturer shall furnish operating instructions for 
the device and accessories that include complete information concerning the accuracy, sensitivity, and use of accessory equipment necessary in obtaining a moisture content.  Operating instructions shall include the following 
information:  
 
(a) name  and address or trademark of the manufacturer;  
 
(b) the type or design of the device with which it is intended to be used;  
 
(c) date of issue;  
 
(d) the kinds or classes of grain or seed for which the device is designed to measure moisture content and test 
weight per bushel; and  
(Amended 2003)  
 
(e) the limitations of us e, including but not confined to the moisture measurement range, grain or seed 
temperature, maximum allowable temperature difference between grain sample and meter, kind or class of 
grain or seed, moisture meter temperature, voltage and frequency ranges, electromagnetic interferences, 
and necessary accessory equipment.  
(Added 1984)  
 
N. Notes  
 N.1. Testing Procedures.  – Field evaluation of grain moisture meters shall be performed by one of the following 
methods:  
 
N.1.1.  Air Oven Reference Method Transfer Standards.  – Official grain samples shall be used as the 
official transfer standards with moisture content and test weight per bushel values assigned by the reference methods.  The reference methods for moisture shall be the oven drying methods as specified by the USDA 
GIPSA.  The test weight per bushel value assigned to a test weight transfer standard shall be the average of 
10 test weight per bushel determinations using the quart kettle test weight per bushel apparatus as specified by 
the USDA GIPSA.  Tol erances shall be applied to the average of at least three measurements on each official 
grain sample.  Official grain samples shall be clean and naturally moist, but not tempered (i.e.,  water not added).  
(Amended 1992, 2001, and 2003)  
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 N.1.2.  Minimum Test.  – A minimum test of a grain moisture meter shall consist of tests using samples 
(need not exceed three) of each grain or seed type for which the device is used, and for each grain or seed type 
shall include the following:  
 
(a) tests of moisture indication s, using samples having at least two different moisture content values 
within the operating range of the device; and  
 (b) if applicable, tests of test weight per volume indications, with at least the lowest moisture samples used 
in (a) above.  
(Added 2003)  
(Amended 1986, 1989, and 2003)  
 
N.1.3.  Meter to Like- Type Meter Method Transfer Standards. –  Properly standardized reference 
meters using National Type Evaluation Program approved calibrations shall be used as transfer standards.  A 
reference meter shall b e of the same type as the meter under test.  Tests shall be conducted side- by-side using, 
as a comparison  medium, grain samples that are clean and naturally moist, but not tempered (i.e.,  water not 
added).  
(Added 2001)  
 
T. Tolerances  
 
T.1. To Underregistration  and to Overregistration.  – The tolerances hereinafter prescribed shall be applied to 
errors of underregistration and errors of over registration.  
 
T.2. Tolerances.  
 
T.2.1.  Air Oven Reference Method.  – Maintenance and acceptance tolerances shall be as shown in 
Table  T.2.1. Acceptance and Maintenance Tolerances Air Oven Reference Method.  Tolerances are expressed 
as a fraction of the percent moisture content of the official grain sample, together with a minimum tolerance.  
(Amended 2001)  
 
Table T.2.1.  
Acceptance and Maintenance Tolerances Air Oven Reference Method  
Type of Grain, Class, or Seed  Tolerance Minimum Tolerance  
Corn, oats, rice, sorghum, 
sunflower  0.05 of the percent  
moisture  content  0.8 % 
in moisture content  
All other cereal grains and oil 
seeds  0.04 of the percent  
moisture  content  0.7 % 
in moisture content  
(Amended 2001)  
 
T.2.2.  Meter to Like- Type Meter Method. – Maintenance and acceptance tolerances shall be as shown 
in Table  T.2.2. Acceptance and Maintenance Tolerances Meter to Like -Type Meter Method.  The tolerances 
shall apply to all types of grain and seed.  
(Added 2001)  
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 Table T.2.2.  
Acceptance and Maintenance Tolerances Meter to Like -Type Meter Method  
Sample Reference Moisture Tolerance 
Up to 22 % 0.5 % 
in moisture content  
(Added 2001)  
 T.3. For Test Weight Per Bushel Indications or Recorded Representations. –  The maintenance and acceptance 
tolerances on test weight per bushel indications or recorded representations shall be as shown in 
Table  T.3. Acceptance and Maintenance Tolerances Test Weight per Bushel.  Tolerances are (+)  positive or 
(−) negative with res pect to the value assigned to the official grain sample.  
(Amended 1992 and 2003)  
 
Table T.3.  
Acceptance and Maintenance Tolerances Test Weight per Bushel  
Type of Grain  
or Seed  Tolerance  
(Pounds Per Bushel)  
Corn, oats  0.8 
All wheat classes  0.5 
Soybeans, all barley classes, all rice 
classes, sunflower, sorghum  0.7 
(Added 2003)  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1.  Value of the Smallest Unit on Primary Indicating and Recording Elements.  – The resolution of 
the moisture meter display shall be 0.1  % moisture and 0.1 pounds per bushel test weight during commercial 
use. 
(Amended 2003)  
 UR.1.2.  See G -UR.1.2.  Environment.  
 
UR.2.  Installation Requirements. – The grain moisture meter shall be ins talled in an environment within the 
range of temperature and/or other environmental factors specified in the operating instructions.  
 
UR.3.  Use Requirements.  
 
UR.3.1.  Operating Instructions.  – The operating instructions for the use of the grain moisture meter shall be 
readily available to the user, service technician, and weights and measures official at the place of installation.  It 
shall include a list of accessory equipment and the kinds of  grain or seed to be measured with the moisture 
meter.  
(Amended 1988)  
 UR.3.2.  Other Devices Not Used for Commercial Measurement.  – If there are other moisture meters on 
the premises not used for trade or determining other charges for services, these devices shall be clearly and conspicuously marked “Not for Use in Trade or Commerce.”  
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 UR.3.3.  Maintaining Integrity of Grain Samples.  – Whenever there is a time lapse (temperature change) 
between taking the sample and testing the sample, means to prevent conde nsation of moisture or loss of 
moisture from grain samples shall be used.  For example, a cold grain sample may be kept in a closed container 
in order to permit the cold grain to come to the operating temperature range of the meter before the grain 
moistur e measurements are made.  
 
UR.3.4.  Printed Tickets.  
 
(a) Printed tickets shall be free from any previous indication of moisture content or type of grain or seed 
selected.  
 
(b) The customer shall be given a printed ticket at the time of the transaction or as  otherwise specified by 
the customer.  The printed ticket shall include the date, grain type, grain moisture results, test weight 
per bushel, and calibration version identification.  The ticket information shall be generated by the 
grain moisture meter sys tem. 
(Amended 1993, 1995, 2003, and 2013)  
 
UR.3.5.  Accessory Devices.  – Accessory devices, if necessary in the determination of a moisture content 
value, shall be in close proximity to the moisture meter and allow immediate use.  
 UR.3.6.  Sampling.  – A grai n sample shall be obtained by following appropriate sampling methods and 
equipment.  These include, but are not limited to grain probes of appropriate length used at random locations in 
the bulk, the use of a pelican sampler, or other techniques and equipm ent giving equivalent results.  The grain 
sample shall be taken such that it is representative of the lot.  
 UR.3.7.  Location.  – Also see G -UR.3.3. Position of Equipment.  
 
UR.3.8.  Level Condition.  – If equipped with a level indicator, a meter shall be maintained in a level 
condition.  
(Added 1988)  
 
UR.3.9.  Current Calibration Data.  – Grain moisture determinations shall be made using only the most 
recently published calibration data.  
(Added 1988)  
 UR.3 .10. Posting of Meter Operating Range.  – The operating range of the grain moisture meter shall be 
clearly and conspicuously posted in the place of business such that the information is readily visible from a reasonable customer position.  The posted inform ation shall include the following:  
 
(a) The temperature range over which the meter may be used and still comply with the applicable requirements.  If the temperature range varies for different grains or seed, the range shall be specified 
for each.  
 
(b) The moisture range for each grain or seed for which the meter is to be used.  
 
(c) The temperature range for each grain or seed for which the meter is to be used.  
 (d) The maximum allowable difference in temperature that may exist between the meter and the sam ple 
for which an accurate moisture determination can be made.  
(Added 1988)  
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 Handbook 44 –  20152016   5.56.(b)  Grain Moisture Meters  
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 Section 5.56. (b) Grain Moisture Meters  
 
 
Section  5.56. was reorganized into two sections beginning with the 1997  Edition of NIST Handbook  44.  This 
Section, 5.56. (b), applies to all  non- NTEP grain moisture meters manufactured or placed into service before 
January 1, 1998.  
(Code reorganized and renumbered 1996)  
 
A. Application  
 
A.1. General.  – This code applies to grain moisture meters; that is, devices used to indicate directly or th rough 
conversion and/or correction tables the moisture content of cereal grain and oil seeds.  The code consists of general 
requirements applicable to all moisture meters and specific requirements applicable only to certain types of moisture 
meters.  
 A.2. Exceptions . – This code does not apply to devices used for in -motion measurement of grain moisture content 
or seed moisture content.  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, 5.56. (b) Grain Moisture 
Meters shall meet the requirements of Section  1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Primary Elements, General.  – A meter shall be equipped with a primary indicating element and 
may also be equipped with a primary recording element.  If the meter indicates directly and/or is equipped to 
record, the meter shall indicate and/or record its measurements in terms of per cent moisture content, wet basis.  
Subdivisions of this unit shall be in terms of decimal subdivisions (not fractions).  If the meter indicates in the conventional scale and requires conversion or correction tables, the resulting values after use  of such t ables 
shall be in terms of percent moisture content, wet basis.  Subdivisions of this unit shall be in terms of decimal 
subdivisions (not fractions).  
 
S.1.2.  Digital Indications.  
 
S.1.2.1.  Measurement Completion.  – A digital indicating element shall not di splay any values (either 
moisture content or conventional scale) before the end of the measurement cycle.  
 
S.1.3.  Graduations.  
 
S.1.3.1.  Length.  – Graduations shall be so varied in length that they may be conveniently read.  
 S.1.3.2.  Width. – In any series of graduations, the width of a graduation shall in no case be greater than 
the width of the minimum clear interval between graduations, and the width of the main graduations shall 
be not more than 50 % greater than the width of subordinate graduations .  Graduations shall in no case be 
less than 0.2  mm (0.008 in) in width.  
 
S.1.3.3.  Clear Interval between Graduations.  – The clear interval shall be not less than 0.75  mm 
(0.03  in) between graduations.  If the graduations are not parallel, the m easurement shall be made:  
 
(a) along the line of relative movement between the graduations at the end of the indicator; or  
 
(b) if the indicator is continuous, at the point of widest separation of the graduations.  
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 S.1.4.  Indicators.  
 S.1.4.1.  Symmetry.  – The index of an indicator shall be symmetrical with respect to the graduations, at 
least throughout that portion of its length associated with the graduations.  
 S.1.4.2.  Length.  – The index of an indicator shall reach to the finest graduations with whic h it is used, 
unless the indicator and the graduations are in the same plane, in which case the distance between the end 
of the indicator and the ends of the graduations, measured along the line of the graduations, shall be not 
more than 1.0  mm (0.04  in). 
 
S.1.4.3.  Width.  – The width of the index of an indicator in relation to the series of graduations with 
which it is used shall be not greater than:  
 
(a) the width of the widest graduation; nor  
 
(b) the width of the minimum clear interval between graduations.  
 
When the index of an indicator extends along the entire length of a graduation, that portion of the index of 
the indicator that may be brought into coincidence with the graduation shall be of the s ame width as the 
graduation throughout the length of the index that coincides with the graduation.  
 
S.1.4.4.  Clearance.  – The clearance between the index of an indicator and the graduations shall in no 
case be more than 1.5  mm (0.06  in). 
 
S.1.4.5.  Parallax . – Parallax effects shall be reduced to the practicable minimum.  
 
S.1.5.  Recording Elements.  
 
S.1.5.1.  General.  – If a meter is equipped with a recording element, it shall record in terms of percent 
moisture content, wet basis only, and not in terms of conventional scale.  
 
S.1.5.2.  Measurement Completion.  – A recording element shall not record any values before the  end of 
the measurement cycle.  
 S.1.5.3.  Range of Moisture Content.  – A recording element shall not record any values when the 
moisture content of the grain sample is beyond the operating range of the device.  
 
S.1.6.  Design of Direct Reading Grain Moisture Meters.  
 
S.1.6.1.  Grain or Seed Kind and Class Selection and Recording.  – Provision shall be made for 
selecting and recording, if equipped to record, the kind and class (as appropriate) of grain or seed to be measured.  The means to select the kind and cl ass of grain or seed shall be readily visible and the kind and 
class of grain or seed selected shall be clearly and definitely identified in letters (such as Wheat or WHT, 
HRWW, etc.).  
 
S.1.6.2.  Operating Range.  – A meter shall automatically and clearly in dicate when the operating range 
of the meter has been exceeded or the manufacturer shall:  
 
(a) clearly  and conspicuously mark the operating ranges on the meter; or  
 
(b) furnish  the operating ranges  of the meter and the means to clearly and conspicuously display this 
information on or immediately adjacent to the device.  
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 The operating range shall specify the following:  
 
(a) the temperature range over which the meter may be used and still comply with the applicable 
requirements;  
 
(b) the moisture range for each grain or seed for which the meter is to be used;  
 
(c) the temperature range for each grain or seed for which the meter is to be used; and  
 
(d) the maximum allowable difference in temperature between the meter and the sample for which an 
accurate moisture determination can be made.  
 
Examples of clearly indicating these conditions include an error indication, flashing the displayed moisture 
value, or blanking the display.  
[Nonretroactive  as of January  1, 1989]  
(Amended 1986 and 1988)  
 S.1.6.3.  Value of Smallest Unit. –  The value of the minimum indicated or recorded moisture indication 
shall not be greater than 0.1  %. 
 
S.1.7.  Electric Power Supply.  
 
S.1.7.1.  Power Supply, Voltage and Frequency.  
 
(a) A meter that operates using alternating current must perform within the tolerances defined in 
Section  T.2. Tolerance Values over the line voltage range 100 V to 130 V, or 200  V to 250 V rms 
as designed, and ov er the frequency range of 59.5 Hz to 60.5 Hz. 
 
(b) Battery -operated instruments shall not indicate or record values outside the applicable tolerance 
limits when battery power output is excessive or deficient.  
[Nonretroactive  as of January  1, 1989]  
 
S.1.7.2.  Power Interruption.  – A power interruption shall not cause an indicating or recording element 
to display or record any values outside the applicable tolerance limits.  
[Nonretroactive  as of January  1, 1989]  
(Added 1988)  
 
S.1.8.  Level Indicating Means.  – A meter shall be equipped with a level indicator and leveling 
adjustments if its performance is changed by an amount greater than the applicable tolerance when the meter is 
moved from a level position to a position that is out of level in any upright dire ction by up to 5 % 
(approximately 3 degrees).  
 
The level -indicating means shall be readable without removing any meter parts requiring a tool.  
[Nonretroactive  as of January  1, 1989]  
(Added 1988) (Amended 1994)  
 
S.1.9.  Operating Temperature.  
 
(a) A meter shall not display or record any usable values until the operating temperature necessary 
for accurate determination has been attained, or the meter shall bear a conspicuous statement 
adjacent to the indication stating that the meter shall be turned on for a time period specified by 
the manufacturer prior to use.  
 
(b) A meter shall meet the requirements of T.2. Tolerance Values when operated in the temperature range of 2  °C to 40 °C (35  °F to 104 °F) or within the range specified by the meter manufacturer.  5.56.(b)  Grain Moisture Meters   Handbook 44 –  20152016  
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(c) If the manufacturer specifies a temperature range, the range shall be at least 10 °C (20  °F) and 
shall be marked on the device.  
[Nonretroactive  as of January  1, 1989]  
(Added 1988)  
 
S.2. Design of Measuring Elements.  
 
S.2.1.  Design of Zero -Setting and Test Point Mechanisms.  – If a grain moisture meter is equipped 
with a zero setting and/or test point mechanism(s), this (these) mechanism(s) shall be adjustable  only with a tool 
outside and entirely separate from this mechanism or enclosed in a cabinet.  This requirement shall not apply to 
manual operations that the operator must make (following operating instructions) in order to obtain a meter 
reading on a grain sample.  
 S.2.2.  Provision for Sealing.  – Provision shall be made for applying a security seal in a manner  that 
requires the security seal to be broken before an adjustment can be made to any component of the grain 
moisture meter that is set by the manufacturer or authorized service representative and not intended to be 
adjusted by the user.  
 
S.3. Accessory Eq uipment.  – When the operating instructions for a moisture meter require accessory equipment 
separate from and external to the moisture meter, such equipment shall be appropriate and complete for the 
measurement.  
 
S.3.1.  Grain -Test Scale.  – If the moisture meter requires the weighing of the grain sample, the weighing 
device shall meet the requirements of the General Code and those applicable portions of the Scales Code.  
 
S.3.2.  Thermometers or Other Temperature Sensing Equipment.  
 
(a) The temperature sensing equipment or thermometer shall be designed to be in direct contact with a 
grain sample in a closed container.  It is acceptable to insert thermometer  through a small hole in the 
lid of the container used to hold the grain sample.  
 
(b) A separate thermometer or other temperature sensing equipment shall have temperature divisions not 
greater than the temperature increments used by the manufacturer in the correction table.  
(Amended 1988)  
 S.3.3.  Conversion and Correction Tables.  – Conversio n and correction tables, charts, graphs, slide 
rules, or other apparatus to convert  the conventional scale values read from a moisture meter to moisture content 
values, if such apparatus is required, shall be appropriate and correct for the moisture meter being used and shall 
be marked with the following information:  
 
(a) name  and address or trademark of the manufacturer;  
 
(b) the type or design of the device with which it is intended to be used;  
 
(c) date of issue;  
 
(d) the kinds or classes of grain or seed for which the device is designed to measure moisture 
content;  
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 (e) the limitations of use, including but not confined to the moisture measurement range, grain or 
seed temperature, kind or class of grain or seed, moisture meter temperature, voltage and 
frequency ranges, electro magnetic  interferences, and necessary accessory equipment; but  
 
(f) values  exceeding any measurement range shall not be included.  
(Added 1984)  
 
S.3.4.  Operating Instructions and Use Limitations.  – Operating instructions shall be furnished by the 
manufacturer with each device with all of the information required by paragraph  S.3.3. Conversion and 
Correction Tables.  Complete information concerning the accuracy, sensitivity, and use of accessory equipment (e.g., test weight per bushel equipment, thermometer, etc.) necessary in obtaining moisture content shall be 
included.  
 
N. Notes  
 
N.1. Testing Procedures.  
 
N.1.1.  Transfer Standards.  – Official grain samples shall be used as the official transfer standards with 
moisture content values assigned by the reference methods.  The reference methods shall be the oven drying 
methods as specified by the USDA GIPSA.  Tolerances shall be applied to the average of at least three 
measurements on each official grain sample.  Official grain samples shall be clean and naturally moist, but not 
tempered (i.e., water not added).  
(Amended 1992)  
 
N.1.2.  Minimum Test.  – A minimum test of a grain moisture met er shall consist of tests with:  
 
(a) samples  (need not exceed three) of each grain or seed for which the device is used; and  
 
(b) samples  having at least two different moisture content values within the operating range of the 
device.  
(Amended 1986 and 1989)  
 
N.1.3 . Temperature Measuring Equipment.  – The accuracy of accessory temperature measuring 
equipment shall be determined by comparison with a calibrated temperature sensor, such as a total immersion 
thermometer with 0.1  °C (0.2  °F) subdivisions, indicating over a range of from 0  °C to 40  °C (32  °F to 104 °F) 
with a maximum error of ±  0.1 °C (0.2  °F).  Tests shall be conducted at two temperatures using liquid baths 
(e.g., ice water and room temperature water).  The two temperatures selected shall not exceed the ra nge of 
temperatures identified in the moisture meter operating instructions.  
(Amended 1988)  
 
T.  Tolerances42 
 
T.1. To Underregistration  and to Overregistration.  – The tolerances hereinafter prescribed shall be applied to 
errors of underregistration  and errors of overregistration . 
 
T.2. Tolerance Values.  – Maintenance and acceptance tolerances shall be as shown in Table T.2. Acceptance and 
Maintenance Tolerances for Grain Moisture Meters.  Tolerances are expressed as a fraction of the percent moistur e 
content of the official grain sample, together with a minimum tolerance.  
 
                                                           
42 These tolerances do not apply to tests in which grain moisture met ers are the transfer standards.  5.56.(b)  Grain Moisture Meters   Handbook 44 –  20152016  
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 Table T.2.  
Acceptance and Maintenance Tolerances for Grain Moisture Meters  
Type of Grain or Seed  Tolerance Minimum Tolerance  
Corn, oats, rice, sorghum, 
sunflower  0.05 of the percent  
moisture  content  0.8 % 
in moisture content  
All other cereal grains  
and oil seeds  0.04 of the percent  
moisture  content  0.7 % 
in moisture content  
 
T.3. For Test Weight Per Bushel Devices.  – The maintenance and acceptance tolerances on separate test weight 
per bushel devices used to determine the test weight per bushel of grain samples for the purposes of making density corrections in moisture determination shall be 0.193  kg/hL or 0.15 lb/bu.  The test methods used shall be those 
specified by the USDA GIPSA using a dockage -free sample of dry hard red winter wheat.  
(Amended 1992 and 2003)  
 
T.4. Thermometers or Other Temperature Sensing Equipment.  – The tolerance for a separate thermometer or 
temperature sensing equipment used to determine the temperature of grain samples for the purpose of making 
temperature corrections in moisture determinations shall be ±  0.5 °C (1  °F). 
(Added 1988)  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  
 
UR.1.1.  Value of the Smallest Unit on Primary Indicating and Recording Elements.  – The value of the 
smallest unit on a moisture meter, whether the moisture meter reads directly in terms of moisture content, or 
when the conventional scale unit is converted or corrected to moisture content, shall be equal to or less 
than 0.1 %. 
 
UR.1.2.  Environment.  – Equipment shall be suitable for the environment in which it is used including, but 
not limited to, the effects of win d, weather, and RFI.  
 UR.2.  Installation Requirements.  – The grain moisture meter shall be installed in an environment within the 
range of temperature and/or other environmental factors specified:  
 
(a) in the operating manual; and  
 
(b) on the conversion or correction tables if such tables are necessary for the operation of the device.  
 
UR.3.  Use Requirements.  
 
UR.3.1.  Operating Instructions.  – The operating instructions for the use of the grain moisture meter shall be 
readily available to the user, service technician, and weights and measures official at the place of installation.  It 
shall include a list of accessory equipment, conversion and correction charts if any are required to obtain 
moisture content values, and the kinds of grain or  seed to be measured with the moisture meter.  
(Amended 1988)  
 
UR.3.2.  Other Devices not used for Commercial Measurement.  – If there are other moisture meters on the 
premises not used for trade or determining other charges for services, these devices shall be clearly and 
conspicuously marked “Not for Use in Trade or Commerce.”  
 
UR.3.3.  Maintaining Integrity of Grain Samples.  – Whenever there is a time lapse (temperature change) 
between taking the sample and testing the sample, means to prevent condensation of moisture or loss of Handbook 44 –  20152016   5.56.(b)  Grain Moisture Meters  
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 moisture from grain samples shall be used.  For example, a cold grain sample may be kept in a clos ed container 
in order to permit the cold grain to come to the operating temperature range of the meter before the grain 
moisture measurements are made.  
 
UR.3.4.  Printed Tickets.  – Printed tickets shall be free from any previous indication of moisture conte nt or 
type of grain or seed selected.  
 
UR.3.5.  Accessory Devices.  – Accessory devices, if necessary in the determination of a moisture content 
value, shall be in close proximity to the moisture meter and allow immediate use.  
 UR.3.6.  Sampling.  – A grain sample shall be obtained by following appropriate sampling methods and 
equipment.  These include, but are not limited to, grain probes of appropriate length used at random locations in 
the bulk, the use of a pelican sampler, or other techniques and equipment giving equivalent results.  The grain sample shall be taken such that it is representative of the lot.  
 
UR.3.7.  Location.  – See G -UR.3.3. Position of Equipment.  
 
UR.3.8.  Level Condition.  – If equipped with a level indicator, a meter shall be maintained in a level 
condition.  
(Added 1988)  
 
UR.3.9.  Operating Limitation.  – Unless otherwise specified by the meter manufacturer, moisture 
determinations shall not be made when the difference in temperatures between the grain sample and the meter 
exceed s 10 °C (20  °F). 
(Added 1988)  
 
UR.3.10.  Current Calibration Chart or Data.  – Grain moisture determinations shall be made using only the 
most recently published calibration charts or calibration data.  
(Added 1988)  
 
UR.3.11.  Posting of Meter Operating Range.  – The operating range of the grain moisture meter shall be 
clearly and conspicuously posted in the place of business such that the information is readily visible from a 
reasonable customer position.  The posted information shall include the following:  
 
(a) The temperature range over which the meter may be used and still comply with the applicable 
requirements.  If the temperature range varies for different grains or seed, the range shall be specified 
for each.  
 
(b) The moisture range for each grain or seed for whi ch the meter is to be used.  
 
(c) The temperature range for each grain or seed for which the meter is to be used.  
 
(d) The maximum allowable difference in temperature that may exist between the meter and the sample 
for which an accurate moisture determination can be made.  
(Added 1988)  
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 Section 5.57.  Near -Infrared Grain Analyzers  
 
 
A. Application  
 
A.1. General.  – This code applies to near -infrared (NIR) grain analyzers; that is, devices used to indicate the 
constituent values (other than moisture content) of grain using near -infrared reflectance or transmittance 
technology.  These instruments may analyze either whole grain or ground grain samples.  The code consists of 
general requirements applicable to all NIR analyzers and specific requirements applicable only to certain 
types of NIR analyzers, grain types, or grain constituents.  In addition to meeting the requirements of this 
code, a whole grain NIR analyzer that displays a measured moisture value must also comply with the 
requirements of the Grain Moisture Meters Code.  
(Added 2001)  
 
A.2. Exceptions.  – This code does not apply to devices used for in- motion measurement of grain constituent 
values.  
 
A.3. Calibrations.  – The National Type Evaluation Program (NTEP) Certificate of Conformance (CC) shall 
indicate the native moisture basis of each calibration.  The “native” moisture basis is the default moisture basis 
of the sealable constituent calibration (or constituent ca libration pair when a non- displayed moisture calibration 
is also involved).  If an NIR analyzer uses a self -generated moisture measurement internally but does NOT 
display or record a moisture value, the moisture calibration shall be considered to be a part  of the constituent 
calibration.  For such calibrations, the CC shall state:  “Includes non- displayed moisture calibration.”  Changes 
to any part of such calibrations shall require changes to the CC.  
(Added 2001)  
 
A.4. Additional Code Requirements . – In ad dition to the requirements of this code, Near -Infrared Grain 
Analyzers shall meet the requirements of Section 1.10. General Code.  
 
S. Specifications  
 
S.1. Design of Indicating, Recording, and Measuring Elements.  
 
S.1.1.  Digital Indications and Recording Elements.  
 
(a) Analyzers shall be equipped with a digital indicating element.  
 
(b) The minimum height for the digits used to display constituent values shall be 10  mm. 
 
(c) Analyzers shall be equipped with a communication interface that permits interfacing with a 
recording element and transmitting the date, grain type or class, constituent values, the moisture 
basis for each constituent value (except moisture), and calibration version identification.  If the 
analyzer converts constituent results to a manually entered m oisture basis, the “native” 
concentration and the “native” moisture basis must appear on the printed ticket in addition to the 
converted results and the manually entered moisture basis.  
(Amended 2001 and 2003)  
 
(d) A digital indicating element shall not displa y, and a recording element shall not record, any 
constituent value before the end of the measurement cycle.  
 
(e) Constituent content shall be recorded and displayed as percent of total mass at the specified 
moisture basis.  The moisture basis shall also be recorded and displayed for each constituent content 
result (except moisture).  If a whole grain analyzer that is calibrated to display results on an “as is” 
moisture basis does NOT display or record a moisture value, it must clearly indicate that results a re 5.57.  Near -Infrared Grain Analyzers   Handbook 44 –  2016  
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 expressed on an “as is” moisture basis.  Ground grain analyzers must ALWAYS display and record 
a moisture measurement for “as is” content results (except moisture).  
(Amended 2001 and 2003)  
 
(f) An analyzer shall not display or record any constituent value t hat is beyond the operating range of 
the device unless the constituent value representation includes a clear error indication (and 
recorded error message with the recorded representation).  
 
(g) If an NIR analyzer is used to determine a moisture value, either t o determine the moisture of an “as 
is” constituent content measurement or to convert from one moisture basis to another, the moisture 
measurement must be concurrent with the measurement of other constituents.  
 
(h) If the analyzer incorporates a built -in pr inter, or if a printer is available as an accessory to the 
analyzer, the information appearing on the printout shall be arranged in a consistent and 
unambiguous manner.  
(Added 2003)  
[Nonretroactive as of January  1, 2003]  
(Added 2001)  
 
S.1.2.  Selecting and Recording Grain Class and Constituent.  – Provision shall be made for selecting 
and recording the type or class or multi -class group of grain and the constituent(s) to be measured.  The means 
to select the grain type or class or multi- class group and the constituent(s) shall be readily visible and the type or 
class or multi -class group of grain and the constituent(s) selected shall be clearly and definitely identified in 
letters (such as HRWW, HRSW, WHEAT, etc., or PROT,  etc.).  A symbol to identify the disp lay of the type or 
class or multi- class group of grain and constituent(s) selected is permitted provided that it is clearly defined 
adjacent to the display.  Minimum acceptable abbreviations are listed in Table  S.1.2. Grain Types and Multi -
Class Groups Con sidered for Type Evaluation and Calibration and Their Minimum Acceptable Abbreviations.  
[Nonretroactive as of January  1, 2003]  
 
If more than one calibration is included for a given grain type, the calibrations must be clearly distinguished 
from one another . 
[Nonretroactive as of January  1, 2004]  
(Amended 2003 and 2007)  
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 Table S.1.2.  
Grain Types and Multi -Class Groups Considered for Type Evaluation and 
Calibration and Their Minimum Acceptable Abbreviations  
Grain Type  Grain Class  Minimum Acceptable 
Abbreviation  
Barley  Two-Rowed Barley  TRB  
Six-Rowed Barley  SRB  
All-Class Barley*  BARLEY  
Corn  --- CORN  
Soybeans  --- SOYB  
Wheat  All-Class Wheat*  WHEAT  
Durum Wheat  DURW  
Hard Red Spring Wheat  HRSW  
Hard Red Winter Wheat  HRWW  
Hard White Wheat  HDWW  
Soft Red Winter Wheat  SRWW  
Soft White Wheat  SWW  
Wheat Excluding Durum*  WHTEXDUR  
[Note:  Grain Types marked with an asterisk (*) are “Multi -Class Calibrations”]  
[Nonretroactive as of January  1, 2003]  
(Table Amended 2001 and 2007)  
 
S.1.3.  Operating Range.  – An analyzer shall automatically and clearly indicate when the operating 
range of the device has been exceeded.  The statement of the operating range shall be specified in the 
operator’s manual and shall operate as follows:  
 
(a) The ambient temperature  range over which the analyzer may be used and still comply with the 
applicable requirements shall be specified.  The minimum temperature range shall be 10  °C to 
30 °C.  No constituent value may be displayed when the temperature range is exceeded.  An 
appr opriate error message shall be displayed when the temperature of the analyzer is outside its 
specified operating range.  
 
(b) The constituent range at the moisture basis specified in Table  N.1.1. Constant Moisture Basis for 
Type Evaluation and Field Inspections  shall be specified for each grain or seed for which the 
analyzer is to be used.  A constituent value may be displayed when the constituent range is exceeded 
if accompanied by a clear indication that the constituent range has been exceeded.  
(Amended 2001)  
 
(c) For whole grain analyzers only, the temperature range shall be specified for each grain or seed for 
which an analyzer is to be used.  The minimum temperature range for each grain shall be 10 °C to 
30 °C.  No constituent value may be displayed when the tem perature range is exceeded.  An 
appropriate error message shall be displayed when the temperature of the grain sample exceeds the 
temperature range for the grain.  The requirements of this subsection  (c) are not applicable to 
ground grain analyzers.  
 
(d) For whole grain analyzers, the maximum allowable difference in temperature between the 
instrument environment (ambient temperature) and the sample for which an accurate constituent 
determination can be made shall be specified.  The minimum temperature range shall cover at least 
10 °C.  No constituent value may be displayed when the maximum allowable temperature difference 
is exceeded.  An appropriate error message shall be displayed when the difference between the 5.57.  Near -Infrared Grain Analyzers   Handbook 44 –  2016  
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 ambient temperature and the sample temperature e xceeds the specified difference.  The 
requirements of this subsection  (d) are not applicable to ground grain analyzers.  
[Nonretroactive and effective as of January  1, 2003]  
 
S.1.4.  Operating Temperature.  
 
(a) An analyzer shall not display or record any usable values until the internal operating temperature 
necessary to meet tolerance requirements has been attained, or the analyzer shall bear a 
conspicuous statement adjacent to the indication stating that the analyzer shall be turned on for a 
time period specified by the manufacturer prior to use.  
 
(b) If an instrument does not meet tolerance requirements because there is an upper internal operating 
temperature limit that could be exceeded when operating within the ambient temperature range 
specified by the manufacturer, then a means of sensing and indicating an over -temperature 
condition must be provided.  
[Nonretroactive as of January  1, 2003]  
 
S.1.5.  Value of Smallest Unit.  – The display shall permit constituent value determination to both 
0.01 % and 0.1 % resolution.  The 0.1  % resolution is for commercial transactions; the 0.01  % resolution is 
for calibration purposes only, not for commercial purposes.  
[Nonretroactive as of January  1, 2003]  
 
S.2. Design of NIR Analyzers.  
 
S.2.1.  Minimum Sample Size.  – Analyzers shall be designed to measure constituent values of 
representative size grain samples.  The minimum allowable sample size used in analysis shall be 20 g. 
[Nonretroactive as of January  1, 2003]  
 
S.2.2.  Electric Power Supply.  
 
S.2.2.1.  Power Supply, Voltage and Frequency. –  An analyzer that operates using alternating current 
must perform within tolerance requirements over the line voltage range 100  V to 130 V and over the 
frequency range of 59.5 Hz to 60.5 Hz. 
[Nonretroactive as of January  1, 2003]  
 
S.2.2.2.  Power Interruption. –  A power interruption shall not cause an indicating or recording 
element to display or record any values outside the applicable tolerance limits.  
[Nonretroactive as of January  1, 2003]  
 
S.2.3.  Level Indicatin g Means.  – Analyzers shall be equipped with a level indicator and leveling 
adjustments if its performance is changed by an amount greater than the tolerance requirement when the 
instrument is moved from a level position into a position that is out of level in any upright direction by up to 
5 % (approximately three degrees).  The level -indicating means shall be readable without removing any 
instrument parts requiring a tool.  
[Nonretroactive as of January  1, 2003]  
 
S.2.4.  Environmental Conditions.  – Instrumen t optics and electronics must be protected from 
exposure to dust by either sealing these areas or by protecting them with a dust filtration system suitable for 
the removal of air -borne grain dust.  
[Nonretroactive as of January  1, 2003]  
 
S.2.5.  Calibration Transfer and Verification.  
 
S.2.5.1.  Calibration Transfer.  – The instrument hardware/software design and calibration procedures 
shall permit calibration development and the mathematical transfer of calibrations between instruments 
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Note:   Only the manufacturer or the manufacturer’s designated service agency may make calibration 
transfer or slope adjustments on near- infrared grain analyzers and, except for instrument failure and 
repair, only during a prescribed period of time during the year.   This does not preclude the possibility of 
the operator installing the manufacturer -specified calibration constants or standardization parameters 
under the instructions of the manufacturer or the manufacturer’s designated service agency.  Nor does it 
preclude operator bias adjustments when made under the conditions specified in UR.2.8. Slope and Bias 
Adjustments.  
[Nonretroactive and effective as of January  1, 2003]  
(Note added 1995) (Amended 1995)  
 
S.2.5.2.  Calibration Version. –  An instrument must be capa ble of displaying either calibration 
constants, a unique calibration name, or a unique calibration version number for use in verifying that 
the latest version of the calibration is being used to make constituent determinations, and that the 
appropriate ins trument settings have been made for the calibration being used.  
[Nonretroactive as of January  1, 2003]  
(Amended 2001)  
 
S.2.5.3.  Calibration Corruption. –  If calibration constants are digitally stored in an electronically 
alterable form, the analyzer shall be designed to make automatic checks to detect corruption of 
calibration constants.  An error message must be displayed if calibration constants have bee n 
electronically altered.  
[Nonretroactive as of January  1, 2003].  
 
S.2.6.  Provision for Sealing.  – An event logger is required in the device; it must include an event 
counter (000 to 999), the parameter ID, the date and time of the change, and the new valu e of the parameter 
(for calibration changes consisting of multiple constants, the calibration version number may be used rather 
than the calibration constants.)  
 
A printed copy of the information must be available through the device or through another on -site device.  
The event logger shall have a capacity to retain records equal to 25 times the number of sealable parameters 
in the device, but not more than 1000 records are required.  (Note:  Does not require 1000  changes to be 
stored for each parameter.)  
[Nonretroactive as of January  1, 2003]  
(Amended 1997)  
 
S.3. Accessory Equipment.  – When the operating instructions for an NIR analyzer require accessory equipment 
separate from and external to the analyzer, such equipment shall be appropriate and complete f or the 
measurement.  
[Nonretroactive as of January  1, 2003]  
 
S.3.1.  Grinders.  – The make and model of grinder used for ground grain NIR analyzers must be specified by 
the manufacturer and required as auxiliary equipment in the determination of constituent values for 
applicable grain types.  
[Nonretroactive as of January  1, 2003]  
 
S.4. Operating Instructions and Use Limitations. –  The manufacturer shall furnish operating instructions for 
the device and accessories that include complete information concerning the accuracy, sensitivity, and use of 
accessory equipment necessary in obtaining a constituent value.  Operating instructions shall include the 
following information:  
 
(a) name and address or trademark of the manufacturer;  
 
(b) the type or design of the device for  which the operating instructions are intended to be used;  
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 (c) date of issue;  
 
(d) the kind or classes of grain or seed for which the device is designed to measure constituent values; and 
 
(e) the limitations of use, including but not limited to constituent range, gr ain or seed temperature, kind or 
class of grain or seed, instrument temperature, voltage and frequency ranges, electromagnetic 
interferences, and necessary accessory equipment.  
[Nonretroactive as of January  1, 2003]  
 
N. Notes  
 
N.1. Testing Procedures.  
 
N.1.1.  Field Inspection.  – Whole grain samples shall be used as the official field inspection 
standards.  Five samples per grain type or class shall be used to check instrument performance.  Each 
sample will be analyzed once.  One of the samples will be an alyzed an additional four times to test 
instrument repeatability.  For ground grain instruments, the ground sample will be repacked four times.  
A new grind is not required.  Test results must be converted to the standard moisture bases shown in 
Table  N.1.1. Constant Moisture Basis for Type Evaluation and Field Inspection before applying the 
tolerances of Table T.2. Acceptance and Maintenance Tolerances for NIR Grain Analyzers.  Test results 
on whole grain analyzers that produce results on an “as is” basis without displaying or recording a 
moisture value shall be converted to the standard moisture bases shown in Table  N.1.1. Constant 
Moisture Basis for Type Evaluation and Field Inspection using sample moisture values determined with 
the facility’s moisture m eter (which must be certified for commercial use).  
(Amended 2001)  
 
Table N.1.1.  
 Constant Moisture Basis for Type Evaluation and Field Inspection  
Grain Type or Class  Constituents(s)  Moisture Basis  
Durum Wheat, Hard Red Spring 
Wheat, Hard Red Winter Wheat, Hard 
White Wheat, Soft Red Winter Wheat, 
Soft White Wheat  Protein  12 %  
Soybeans  Protein  
Oil 13 %  
Two-rowed Barley  
Six-rowed Barley  Protein  0 % (dry basis)  
Corn  Protein  
Oil 
Starch  0 % (dry basis)  
[Nonretroactive as of January  1, 2003]  
(Table Added 2001)  
 
Constituent values shall be assigned to test samples by the Grain Inspection, Packers and Stockyards 
Administration (GIPSA).  Tolerances shall be applied to individual sample measurements, the average of 
individual measurements on each of the  five test samples, and the maximum difference (range) in results for 
five analyses on one of the test samples.  
(Amended 2001)  
 
N.1.2.  Standard Reference Samples.  – Reference samples used for field inspection purposes shall be 
clean and selected to reasonably represent the constituent range.  These samples shall be selected such 
that the difference between constituent values obtained using the GIPSA standard referenc e method and 
an official GIPSA NIR grain analyzer does not exceed one -half of the acceptance tolerance shown in Handbook 44 –  2016   5.57.  Near -Infrared Grain Analyzers  
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 Table  T.2. Acceptance and Maintenance Tolerances for NIR Grain Analyzers for individual test samples 
or 0.375 times the acceptance tolerance sho wn for the average of five samples.  
(Amended 2001and 2003)  
 
T. Tolerances  
 
T.1. To Under registration and to Over registration.  – The tolerances hereinafter prescribed shall be applied 
to errors of underregistration and errors of overregistration and shall be based on constituent values 
expressed at the moisture bases shown in Table  N.1.1. Constant Moisture Basis for Type Evaluation and Field 
Inspection.  
(Amended 2001)  
 
T.2. Tolerance Values.  – Acceptance and maintenance tolerances shall be equal.  Tol erances for individual 
samples and the average for five samples are as shown in Table  T.2. Acceptance and Maintenance Tolerances 
for NIR Grain Analyzers.  
 
Table T.2.  
Acceptance and Maintenance Tolerances for NIR Grain Analyzers  
Type or Class of 
Grain  Constituent  Individual Samples 
(percent)  Average for Five 
Samples (percent)  Range for Five 
Retests (percent)  
Durum Wheat, Hard 
Red Spring Wheat, 
Hard Red Winter 
Wheat, Hard White 
Wheat, Soft Red 
Winter Wheat, Soft 
White Wheat  protein  0.60 0.40 0.40 
Soybeans  protein  0.80 0.60 0.60 
oil 0.70 0.50 0.50 
Two -rowed Barley  
Six-rowed Barley  protein  0.70 0.50 0.50 
Corn  protein  0.80 0.60 0.60 
oil 0.70 0.50 0.50 
starch  1.00 0.80 0.80 
(Amended 2001)  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  – The NIR analyzer shall be installed in an environment within the range 
of temperature and/or other environmental factors specified in the operating manual.  
 
UR.2.  User Requirements.  
 
UR.2.1.  Operating Instructions.  – The operating instructions for the NIR analyzer shall be readily 
available to the user, service technician, and weights and measures official at the place of installation.  It 
shall include a list of accessory equipment if any are required to obtain const ituent values, and the type 
or class of grain to be measured with the NIR analyzer.  If an NIR analyzer has the capability, the user is 
permitted to select the moisture basis to be used on any measurement.  
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UR.2.2.  Other Devices Not Used for Commercial Measurement.  – If there are other NIR analyzers on 
the premises not used for trade or determining other charges for services, these devices shall be clearly 
and conspicuously marked “Not for Use in Trade or Commerce.”  
UR.2.3.  Printed Tickets.  
 
(a) Printed tickets shall be free from any previous indication of constituent or grain type 
selected.  The printed ticket shall indicate constituent values and the moisture basis 
associated with each constituent value (except moisture).  If the analyzer is calibrated to 
display results on an “as is” moisture basis and does NOT display or record a moisture 
value, the ticket must clearly indicate that results are expressed on an “as is” moisture 
basis.  
(Amended 2001)  
 
(b) The customer shall be given a printed ticket showing the date, grain type or class, 
constituent results, and calibration version identification.   If the analyzer converts 
constituent results to a manually entered moisture basis, the “native” concentration and the 
“native” moisture basis must appear on the printed ticket in addition to the converted 
results and the manually entered moisture basis.  If the manually entered moisture basis is 
intended to be the moisture value for an “as is” constituent concentration measurement, 
that moisture value must h ave been obtained on the same sample and must have been 
measured on a moisture meter certified for commercial use.  The information presented on 
the ticket shall be arranged in a consistent and unambiguous manner.  The ticket shall be 
generated by the near -infrared grain analyzer system.  
[Nonretroactive as of January  1, 2003]  
(Amended 2001)  
 
UR.2.4.  Grinders.  – Place grinders in a separate room from the NIR analyzer to avoid instrument 
contamination.  If a separate room is not available, the grinder may be in the same room with the NIR 
analyzer provided the grinder is not placed within one  meter of the air intake on the NIR.  
 
UR.2.5.  Sampling.  – Samples shall be obtained by following appropriate sampling methods and 
equipment.  These include, but are not limited to grain probes of appropriate length used at random 
locations in the bulk, the use of a pelican sampler, or other techniques and equipment giving equivalent 
results.  The sample shall be taken such that it is representative of the lot.  If an NIR analyzer permits 
user entry of the moisture value for an “as is” constituent measurement, that moisture value must have 
been obtained on the same sample and must have been measured on a moisture meter certified for 
commercial use.  
(Amended 2001)  
 
UR.2.6.  Level Condition.  – If equipped with a level indicator, an analyzer shall be maintained in a level 
condition.  
 
UR.2.7.  Operating Limitation.  – Constituent determinations shall not be made when the difference in 
temperatures between the grain sample and the i nstrument environment (ambient temperature) exceeds 
manufacturer recommendations.  
 
UR.2.8.  Slope and Bias Adjustments.  – Bias changes shall be made only on the basis of tests run on a 
current set of Standard Reference Samples (SRS) traceable to GIPSA Master Instruments.43  A written 
explanation and record of all calibration changes, including those changes made by a manufacturer or 
                                                           
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 the manufacturer’s designated service agency, shall be maintained.  The log shall indicate the date and 
magnitude of changes in bias and slope constants and the instrument serial number.  A Calibration 
Adjustment Data Sheet for each log entry shall be available for inspection upon request by the field 
inspector.  Data Sheets shall be retained by the user for a period of no less tha n 18 months following any 
calibration adjustment.  The Data Sheet must show:  date of test and adjustment, serial number of the 
instrument, calibration identification, the nature of the adjustment, the unique identification number and 
source of sample sets  used, and, for each sample in the set, reference values, initial instrument results 
(except in the cases of instrument failure and repair), and instrument results after calibration adjustment 
or instrument repair.  
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 Section 5.58.  Multiple Dimension Measuring Devices  
 
 
A. Application  
 
A.1. General.  – This code applies to dimension and volume measuring devices used for determining the 
dimensions and/or volume of objects for the purpose of calculating freight, storage, or postal charges based on the 
dimensions and/or volume occupied by the obj ect.  A multiple dimension measuring device: 
 
(a) is generally used to measure hexahedron -shaped objects; and  
(Added 2008)  
 
(b) may be used to measure irregularly -shaped objects.  
(Added 2008)  
(Amended 2008)  
 
A.2. Other Devices Designed to Make Multiple Measurement Automatically to Determine a Volume.  – 
Insofar as they are clearly applicable, the provisions of this code apply also to devices designed to make multiple 
measurements automatically to determine a volume for  other applications as defined by Section 1.10. General Code 
paragraph  G-A.1. Commercial  and Law -Enforcement Equipment.  
 
A.3. Additional Code Requirements.  – In addition to the requirements of this code, Multiple Dimension 
Measuring Devices shall meet the requirements of Section  1.10. General  Code.  
 A.4. Exceptions. – This code does not apply to:  
 
(a) devices  designed to indicate automatically  (with or without value -computing capabilities) the length of 
fabric passed through the measuring elements  (also see Section  5.50. for Fabric -Measuring Devices);  
 
(b) devices  designed to indicate automatically the length of cordage, rope, wire, cable, or similar flexible 
material passed through the measuring elements (also see Section  5.51. for Wire - and Cordage -Measuring 
Devices); or  
 
(c) any linear meas ure, measure of length, or devices used to measure individual dimensions for the purpose of 
assessing a charge per unit of measurement of the individual dimension (also see Section  5.52. for Linear 
Measures).  
 A.5. Type Evaluation.  – The National Type Eval uation Program (NTEP) will accept for type evaluation only 
those devices that comply with all requirements of this code.  
 
S. Specifications  
 
S.1. Design of Indicating and Recording Elements and of Recorded Representations.  
 
S.1.1.  Zero or Ready Indication.  
 
(a) Provision shall be made to indicate or record either a zero or ready condition.  
 
(b) A zero or ready condition may be indicated by other than a continuous digital zero indication, provided 
that an effective automatic means is provided to inhibit a me asuring operation when the device is in an 
out-of-zero or non- ready condition.  
 
S.1.2.  Digital Indications.  – Indicated and recorded values shall be presented digitally.  
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  S.1.3.  Negative Values.  – Except when in the tare mode, negative values shall not be indicated or 
recorded.  
 
S.1.4.  Dimensions Indication.  – If in normal operation the device indicates or records only volume, a 
testing mode shall be provided to indicate dimensions for all objects measured.  
 
S.1.5.  Value of Dimension/Volume Division Units.  – The value of a device division “d” expressed in a 
unit of dimension shall be presented in a decimal format with the value of the division  expressed as:  
 
(a) 1, 2, or  5;  
 
(b) a decimal multiple or submultiple of 1, 2, or  5; or 
 
(c) a binary submultiple  of a specific U.S. customary unit of measure.  
 
Examples:  device divisions may be 0.01, 0.02, 0.05; 0.1, 0.2, or  0.5; 1, 2, or  5; 10, 20, 50, or  100; 0.5, 0.25, 
0.125, 0.0625,  etc. 
 
S.1.5.1.  For Indirect Sales.  – In addition to the values specified in S.1.5. Value of Dimension/Volume 
Division Units, the value of the division may be 0.3  inch and 0.4  inch.  
 
S.1.5.2.  Devices Capable of Measuring Irregularly -Shaped Objects. –  For devices capable of 
measuring irregul arly shaped objects, the value of the division size (d) shall be the same for the length 
axis (x) and the width axis  (y) and may be different for the height axis  (z), provided that electronic rotation 
of the object to determine the smallest hexahedron is calculated in only a two -dimension horizontal plane, 
retaining the stable side plane as the bottom of the hexahedron.  
(Added 2008)  
 
S.1.6.  Customer Indications and Recorded Representations.  – Multiple dimension measuring devices 
or systems must provide information as specified in Table S.1.6. Required Information to be Provided by 
Multiple Dimension Measuring Systems.  As a minimum, all devices or systems must be able to meet either 
column  I or column  II in Table  S.1.6. Required Information to be Provided by  Multiple Dimension Measuring 
Systems.  
(Amended 2004)  
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 Table S.1.6.  
Required Information to be Provided by Multiple Dimension Measuring Systems  
Information  Column I1 Column II1 Column III  
Provided by 
device Provided by invoice or 
other  means  Provided by 
invoice or other 
means as 
specified in 
contractual 
agreement   Customer  
present  Customer 
not present  
1.  Device identification2 D or P  P P P or A  
2.  Error message (when applicable)  D or P  P N/A N/A 
3.  Hexahedron dimensions3 D or P  P P P or A 
4.  Hexahedron volume (if used)3 D or P  P P P or A  
5.  Actual weight (if used)3 D or P  P P P or A  
6.  Tare (if used)3 D or P  N/A N/A N/A 
7.  Hexahedron measurement statement4 D or P or M  P P P or G  
A = AVAILABLE UPON REQUEST BY CUSTOMER5 
D = DISPLAYED  
G = PUBLISHED GUIDELINES OR CONTRACTS  
M = MARKED  
N/A = NOT APPLICABLE  
P = PRINTED or RECORDED IN A MEMORY DEVICE and AVAILABLE UPON REQUEST BY 
CUSTOMER5 
 
Notes:  
1 As a minimum all devices or systems must be able to meet either column  I or column  II. 
2 This is only required in systems where more than one device or measuring element is being used.  
3 Some devices or systems may not utilize all of these values; however as a minimum either hexahedron 
dimensions or hexahedron volume must be displ ayed or printed.  
4 This is an explanation that the dimensions and/or volume shown are those of the smallest hexahedron in which the 
object that was measured may be enclosed rather than those of the object itself.  
5 The information “available upon request b y customer” shall be retained by the party having issued the invoice for 
at least 30  calendar days after the date of invoicing.  
(Amended 2004)  
 
S.1.7.  Minimum Lengths.  – Except for entries of tare, the minimum length to be measured by a device 
is 12  divisions.  The manufacturer may specify a longer minimum length.  
 
S.1.8.  Indications Below Minimum and Above Maximum.  – When objects are smaller than the 
minimum dimensions  identified in paragraph  S.1.7. Minimum Lengths or larger than any of the maximum 
dimensions plus 9 d, and/or maximum volume marked on the device plus 9 d, or when a combination of 5.58.  Multiple Dimension Measuring Devices   Handbook 44 –  20152016  
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  dimensions for the object being measured exceeds the measurement capability  of the device, the indicating or 
recording element shall either:  
 
(a) not indicate or record any usable values; or  
 (b) identify  the indicated or recorded representation with an error indication.  
(Amended  2004)  
 S.1.9.  Operating Temperature.  – An indicating or recording element shall not indicate nor record any 
usable values until the operating temperature necessary for accurate measuring and a stable zero reference or 
ready condition has been attained.  
 S.1.10.  Adjustable  Components.  – Adjus table components shall be held securely in adjustment and, 
except for a zeroing mechanism (when applicable), shall be located within the housing of the element.  
 
S.1.11.  Provision for Sealing.  
 
(a) A device shall be designed with provision(s) for applying a security seal that must be broken, or for 
using other approved means of providing security (e.g., data change audit trail available at the time of inspection), before any change that detrimentally  affects the metrological integrity of the device can be 
made to any measuring element.  
 (b) Audit trails shall use the format set forth in Table  S.1.11. Categories of Devices and Methods of 
Sealing for Multiple Dimension Measuring Systems.  
 
Table S.1.11.   
Categories of Devices and Methods of Sealing for Multiple Dimension Measuring Systems  
Categories of Devices  Methods of Sealing  
Category  1:  No remote configuration.  Seal by physical seal or two event counters:  one for 
calibration parameters and one for  configuration 
parameters.  
Category  2:  Remote configuration capability, but 
access is controlled by physical hardware.  
 
Device shall clearly indicate that it is in the remote 
configuration mode and record such message if 
capable of printing in this mode.  The hardware enabling access for remote 
communication must be at the device and sealed using a physical seal or two event counters:  one for calibration 
parameters and one for  configuration parameters.  
Category  3:  Remote configuration capability access 
may be unlimited or controlled through a software 
switch (e.g., password). An event logger is required in the device; it must include 
an event counter (000  to 999), the parameter ID, the date 
and time of the change, and the new value of the 
parameter.  A p rinted copy of the information must be 
available through the device or through another on- site 
device.  The event logger shall have a capacity to retain records equal to 10 times the number of sealable  
parameters in the device, but not more than 1000 recor ds 
are required.  ( Note :  Does not require 1000 changes to 
be stored for each parameter.)  
 
S.2. Design of Zero and Tare.  
 
S.2.1.  Zero or Ready Adjustment.  – A device shall be equipped with means  by which the zero 
reference or ready condition can be adjusted, or the zero reference or ready condition shall be automatically Handbook 44 –  20152016   5.58.  Multiple Dimension Measuring Devices  
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 maintained.  The zero reference or ready control circuits shall be interlocked so that their use is prohibited 
during measureme nt operations.  
 
S.2.2.  Tare.  – The tare function shall operate only in a backward direction (that is, in a direction of 
under registration) with respect to the zero reference or ready condition of the device.  The value of the tare 
division or increment shall be equal to the division of its respective axis on the device.  There shall be a clear 
indication that tare has been taken.  
 S.3. Systems with Two or More Measuring Elements.  – A multiple dimension measuring system with a single 
indicating or recording  element, or a combination indicating -recording element, that is coupled to two or more 
measuring elements with independent measuring systems, shall be provided with means to prohibit the activation of 
any measuring element (or elements) not in use, and shall be provided with automatic means to indicate clearly and 
definitely which measuring element is in use.  
 
Note:  This requirement does not apply to individual devices that use multiple emitters/sensors within a device in combination to 
measure objects in the same measurement field.  
(Amended 2004)  
 
S.4. Marking Requirements.   (Also see G -S.1. Identification, G -S.4. Interchange or Reversal of Parts, 
G-S.5.2.5. Permanence, G -S.6. Marking Operational Controls, Indications, and Features, G -S.7. Lettering, 
G-UR.2.1.1. Visibility of Identification, and G -UR.3.1. Method of Operation.)  
 
S.4.1.  Multiple Dimension Measuring Devices, Main Elements, and Components of Measuring 
Devices.  – Multiple dimension measuring devices, main elements of multiple dimension measurin g devices 
when not contained in a single enclosure for the entire dimension/volume measuring device, and other 
components shall be marked as specified in Table S.4.1.a. and explained in the accompanying notes, 
Table  S.4.1.b. Multiple Dimension Measuring Sy stems Notes for Table  S.4.1.a.  
 
Table S.4.1.a.  
Marking Requirements for Multiple Dimension Measuring Systems  
  
  
 
To Be Marked With   Multiple Dimension Measuring Equipment  
Multiple 
Dimension 
Measuring Device 
and Indicating 
Element in Same 
Housing  Indicating 
Element not 
Permanently 
Attached to 
Multiple 
Dimension 
Measuring 
Element  Multiple 
Dimension 
Measuring 
Element not 
Permanently 
Attached to the 
Indicating 
Element  Other 
Equipment  
(1) 
Manufacturer’s ID  x x x x 
Model Designation  x x x x 
Serial Number and Prefix  x x x      x (2)  
Certificate of Conformance Number  (8) x x x      x (8)  
Minimum and Maximum Dimensions 
for Each Axis                                         (3) x x x  
Value of Measuring Division, d  
(for each axis and range)  x x x  
Temperature Limits                            (4) x x x  
Minimum & Maximum speed            (5) x x x  
Special Application                            (6)  x x x  
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Table S.4.1.b.  
Multiple Dimension Measuring Systems Notes for Table S.4.1.a.  
1. Necessary to the dimension and/or volume measuring system, but having no effect on the measuring value, 
e.g., auxiliary remote display, keyboard, etc.  
 
2. Modules without “intelligence” on a modular system (e.g.,  printer, keyboard module, etc.) are not required to have 
serial numbers.  
 
3. The minimum and maximum dimensions (using upper or lower case type) shall be marked.  For example:  
                  Length:  min  _______  max  _______  
                  Width:  min  _______  max  _______  
                  Height:  min  _______  max  _______  
 
4. Required if the range is other than − R10 10 °C to 40 °C (14  °F to 104 °F). 
 
5. Multiple dimension  measuring devices, which require that the object or device be moved relative to one another, 
shall be marked with the minimum and maximum speeds at which the device is capable of making measurements 
that are within the applicable tolerances.  
 6. A device designed for a special application rather than general use shall be conspicuously marked with suitable 
words visible to the operator and the customer restricting its use to  that application.  
 
7. Materials, shapes, structures, combination of object dimensio ns, speed, spacing, minimum protrusion size, or 
object orientations that are inappropriate for the device or those that are appropriate.  
 
8. Required only if a Certificate of Conformance has been issued for the equipment.  
(Amended 2004 and 2008)  
 
S.4.2.  Location of Marking Information.  – The required marking information shall be so located that it 
is readily observable without the necessity of the disassembly of a part requiring the use of any means separate from the device.  
 
N. Notes  
 
N.1. Test Procedures.  
 
N.1.1.  General.  – The device shall be tested using test standards and objects of known and stable 
dimensions.  
 
N.1.2.  Position Test.  – Measurements are made using different positions of the test object and consistent 
with the manufacturer’s specified use for the device.  
 
N.1.2.1.  Irregularly -Shaped Test Object Placement. –  Irregularly -shaped test objects must be 
measured while placed on a stable side.  The rotation of the object to determine the smallest hexahedron 
should be calculated in a two -dimensi onal plane, retaining the stable side plane as  the bottom of the 
hexahedron.  
(Added 2008)  
 
N.1.3.  Disturbance Tests, Field Evaluation.  – A disturbance test shall be conducted at a given 
installation when the presence of disturbances specified in T.6. has  been verified and characterized if those 
conditions are considered “usual and customary.”  
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 N.1.4.  Test Object Size.  – Test objects may vary in size from the smallest dimension to the largest 
dimension marked on the device, and for field verification examinations, shall be an integer multiple of  “d.” 
 
N.1.4.1.  Test Objects.  – Verification of devices may be conducted using appropriate test objects of 
various sizes and of stable  dimensions.  Test object dimensions must be known to an expanded uncertainty 
(cover age factor k  = 2) of not more than one -third of the applicable device tolerance.  The dimensions shall 
also be checked to the same uncertainty when used at the extreme values of the influence factors.  
 
The dimension of all test objects shall be verified using a reference standard that is traceable to NIST (or 
equivalent national laboratory) and meet the tolerances expressed in NIST Handbook  44 Fundamental 
Considerations, paragraph  3.2. ( i.e., one -third of the smallest tolerance applied to the device).  
(Added 2004)  
 
N.1.4.2.  Irregularly -Shaped Test Objects . – For irregularly -shaped test objects, at least one angle shall 
be obtuse and the smallest dimension for an axis shall be equal to or greater than the minimum dimension 
for that axis.  
(Added 2008)  
 (Amended 2008 and 2012)  
 
N.1.5.  Digital Zero Stability.  – A zero indication change test shall be conducted on all devices which 
show a digital zero.  After the removal of any test object, the zero indication shall not change.  ( Also see 
G-UR.4.2. Abnormal P erformance.)  
 
T. Tolerances  
 
T.1. Design.  – The tolerance for a multiple dimension measuring device is a performance requirement 
independent of the design principle used.  
 
T.2. Tolerance Application.  
 
T.2.1.  Type Evaluation.  – For type evaluations, the tolerance values apply to tests within the influence 
factor limits of temperature and power supply voltage specified in T.5.1. Temperature and T.5.2. Power Supply 
Voltage.  
 
T.2.2.  Subsequent Verification.  – For subsequent verif ications, the tolerance values apply  regardless of 
the influence factors in effect at the time of the verification.  ( Also see G -N.2. Testing with Nonassociated 
Equipment.)  
 T.2.3.  Multi -interval (Variable Division -Value) Devices.  – For multi -interval devi ces, the tolerance 
values are based on the value of the device division of the range in use.  
 T.3. Tolerance Values.  – The maintenance and acceptance tolerance values shall be ±  1 division . 
(Amended 2004)  
 
T.4. Position Tests.  – For a test standard measured several times in different positions by the device all 
indications shall be within applicable tolerances.  
 
T.5. Influence Factors.  – The following factors are applicable to tests conducted under controlled conditions 
only.  
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  T.5.1.  Temperature.  – Devices shall satisfy the tolerance requirements under the following temperature 
conditions.  
 
T.5.1.1.  Temperature Limits. –  If not marked on the device, the temperature limits shall be − 10 °C to 
40 °C (14  °F to 104 °F). 
 
T.5.1.2.  Minimum Temperature Range. –  If temperature limits are specified for the device, the range 
shall be at least 30  °C or 54 °F. 
 
T.5.1.3.  Temperature Effect on Zero Indication.  – The zero indication shall not vary by more than one 
division per 5  °C (9 °F) change in temperature.  
 
T.5.2.  Powe r Supply Voltage.  
 
T.5.2.1.  Alternating Current Power Supply. –  Devices that operate using alternating current must 
perform within the conditions defined in paragraphs  T.3. through T.6., inclusive, from −  15 % to +  10 % of 
the marked nominal line voltage(s ) at 60  Hz, or the voltage range marked by the manufacturer, at 60  Hz. 
(Added 2004)  
 
T.5.2.2.  Direct Current Power Supply. – Devices that operate using direct current shall operate and 
perform within the applicable tolerance at any voltage level at which the device is capable of displaying 
metrological registrations.  
(Added 2004)  
(Amended 2004)  
 
T.6. Disturbances, Field Evalua tion.  – The following requirements apply to devices when subjected to 
disturbances which may normally exist in the surrounding environment.  These disturbances include radio frequency 
interference (RFI), electromagnetic interference (EMI), acoustic changes , ambient light emissions, etc.  The 
difference between the measurement indication with the disturbance and the measurement indication  without the 
disturbance shall not exceed one division  “d” or the equipment shall:  
 
(a) blank the indication;  
 
(b) provide  an error message; or  
 
(c) the indication shall be so completely unstable that it could not be interpreted, or transmitted into memory or 
to a recording element, as a correct measurement value.  
 
UR. User Requirements  
 
UR.1.  Selection Requirements.  – Equipment shall be suitable for the service in which it is used with respect to 
elements of its design, including but not limited to, its maximum capacity, value  of the division, minimum capacity, 
and computing capability.  
 
UR.1.1.  Value of the Indicate d and Recorded Division.  – The value of the division recorded shall be the 
same as the division value indicated.  
 
UR.2.  Installation Requirements.  
 
UR.2.1.  Supports.  – A device that is portable and is being used on a counter, table, or the floor shall be so 
positioned that it is firmly and securely supported.  
 
UR.2.2.  Foundation, Supports, and Clearance.  – The foundations and support of a device installed in a 
fixed location shall be such as to provide strength, rigidity, and permanence of all components, and clearance 
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 empty, nor throughout the performance range of the device such that the operation or performance of the device 
is adversely affect ed. 
 
UR.2.3.  Protection from Environmental Factors.  – The indicating and measuring elements of a device 
shall be adequately protected from environmental factors such as wind, weather, and RFI that may adversely 
affect the operation or performance of the de vice.  
 
UR.3.  Use Requirements.  
 
UR.3.1.  Minimum and Maximum Measuring Ranges.  – A device shall not be used to measure objects 
smaller than the minimum or larger than the maximum dimensions marked on the device.  
 
UR.3.2.  Special Designs.  – A multiple dimens ion measuring device designed and marked for a special 
application shall not be used for other than its intended purpose.  
 
UR.3.3.  Object Placement.  – If the object being measured must be transported (e.g., shipped) on a stable 
side, that irregularly -shape d object must be measured while placed on that stable side.  The electronic rotation 
of the object to determine the smallest hexahedron shall be calculated in a two -dimensional horizontal plane, 
retaining the stable side plane as  the bottom of the hexahedron.  
(Added 2008)  
(Amended 2008)  
 
UR.4.  Maintenance Requirements.  
 
UR.4.1.  Zero or Ready Condition.  – The zero -setting adjustment of a multiple dimension measuring device 
shall be maintained so that, with no object in or on the measuring element, the device shall indicate or record a 
zero or ready condition.  
 
UR.4.2.  Level Condition.  – If a multiple dim ension measuring device is equipped with a level -condition 
indicator, the device shall be maintained in a level condition.  
 UR.4.3.  Device Modification.  – The measuring capabilities of a device shall not be changed from the 
manufacturer’s design unless the  modification has been approved by the manufacturer and the weights and 
measures authority having jurisdiction over the device.  
 
UR.5.  Customer Information Provided.  – The user of a multiple dimension measuring device or system shall 
provide transaction in formation to the customer as specified in Table  UR.5. Customer Information Provided.  
(Added 2004)  
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  Table UR.5.  
Customer Information Provided  
Information  No Contractual Agreement  
Contractual 
Agreement  Customer 
Present  Customer not Present  
1. Object identification  N/A P P or A  
2. Billing method (scale or dimensional weight if used)  D or P  P P or A  
3. Billing rate or rate chart D or P or A  P or G or A  P or A  
4. Dimensional weight (if used)  P P P or A  
5. Conversion factor (if dimensional weight is used)  D or P or A  P P or G  
6. Dimensional weight statement1 (if dimensional 
weight is used)  D or P  P P or G  
7. Total price  P P P or A  
A = Available upon Request by Customer2 
D = Displayed  
G = Published Guidelines or Contracts  
M = Marked  
N/A = Not Applicable  
P = Printed  
 
Notes:  
1 This is an explanation that the dimensional weight is not a true weight but is a calculated value obtained by 
applying a conversion factor to the hexahedron dimensions or volume of the object.  
2 The information “available upon request by customer” shall be retained by the party having issued the invoice for 
at least 30  calendar days after the date of invoicing.  
(Added 2004)  
 
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 Section 5.59.  Electronic Livestock, Meat, and Poultry Evaluation Systems 
and/or Devices 
 
 
The status of Section 5.59.  Electronic Livestock, Meat, and Poultry Evaluation Systems and/or Devices was changed  
from “tentative” to “permanent” effective January 1, 2013.  
(Added 2005) (Amended 2012)  
 
A. Application  
 
A.1. General.  – This code applies to electronic devices or systems  for measuring the composition or quality 
constituents of live animals, livestock and poultry carcasses, and individual cuts of meat or a combination thereof for the purpose of determining value.  
 A.2. Additional Code Requirements.  – In addition to the requirements of this code, Electronic Livestock, Meat, 
and Poultry Evaluation Systems shall meet the requirements of Section 1.10. General Code.  
 
A.3. Exceptions . – This code does not apply to scales used to weigh live animals, livestock and poultry carcas ses, 
and individual cuts of meat unless the scales are part of an integrated system designed to measure composition or 
quality constituents.  Scales used in integrated systems must also meet NIST Handbook  44, Section  2.20. Scale 
requirements.  
 
S. Specifica tions  
 S.1. Design and Manufacture.  – All design and manufacturing specifications shall comply with American 
Society for Testing Materials (ASTM) International Standard F2342 Standard Specification for Design and Construction of Composition or Quality Constituent Measuring Devices or Systems.  
 
N. Notes  
 N.1. Method of Test.  – Performance tests shall be conducted in accordance with ASTM Standard F2343 Test 
Method for Livestock, Meat, and Poultry Evaluation Devices.  
 N.2. Testing Standards.  – ASTM Standard F2343 requires device or system users to maintain accurate reference 
standards that meet the tolerance expressed in NIST Handbook  44 Fundamental Considerations, 
paragraph  3.2. Tolerances for Standards (i.e.,  one-third of the smallest tolerance applied ). 
 
N.3. Verification.  – Device or system users are required to verify and document the accuracy of a device or 
system on each production day as specified by ASTM Standard F2341 Standard Practice of User Requirements for 
Livestock, Meat, and Poultry Evaluation Devices or Systems.  
 
N.3.1.  Official Tests.  – Officials are encouraged to periodically witness the required “in house” 
verification of accuracy.  Officials may also conduct official tests using the on -site testing standards or other 
appropriate standards belonging to the jur isdiction with statutory authority over the device or system.  
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 T. Tolerances  
 
T.1. Tolerances on Individual Measurements.  – Maintenance and acceptance tolerances on an individual 
measurement shall be as shown in Table  T.1. Tolerances.  
 
Table T.1.  
Tolerances  
Individual linear measurement of a single constituent  ± 1 mm (0.039 in) 
Measurement of area ± 1.6 cm2 (0.25 in2) 
For measurements of other constituents  As specified in ASTM Standard F2343  
 
UR. User Requirements  
 
UR.1.  Installation Requirements.  
 
UR.1.1.  Installation.  – All devices and systems shall be installed in accordance with manufacturer’s 
instructions.  
 
UR.2.  Maintenance of Equipment.  
 
UR.2.1.  Maintenance.  – All devices and systems shall be continually  maintained in an accurate condition 
and in accordance with the manufacturer’s instructions and ASTM Standard F2341.  
 UR.3.  Use Requirements.  
 
UR.3.1.  Limitation of Use.  – All devices and systems shall be used to make measurements in a manner 
specified by the manufacturer.  
 
UR.4.  Testing Standards.  – The user of a commercial device shall make available to the official with statutory 
authority over the device testing standards that meet the tolerance expressed in Fundamental Considerations, 
paragraph  3.2. To lerances for Standards (i.e.,  one-third of the smallest tolerance applied).  The accuracy of the 
testing standards shall be verified annually or on a frequency as required by the official with statutory authority and shall be traceable to the appropriate S I standard.