Section 2

**Page**

**2.20. Scales 2-3**

2.21. Belt-Conveyor Scale Systems 2-41

2.22. Automatic Bulk Weighing Systems 2-51

2.23. Weights 2-57

2.24. Automatic Weighing Systems - Tentative Code 2-61

### Sec. 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
Scales.** - 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.** Also see General Code requirements.

# 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 digital indication when the scale is in an
> out-of-balance condition.
>
> (Added 1987) (Amended 1987 and 1993)
>
> **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.*
>
> *\[Nonretroactive as of January 1, 1993\]*

(Amended 1992)

> **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 prior to the
> gross load value.
>
> (Added 1983)
>
> ***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;*
>
> *(c) a binary submultiple of a specific unit of weight.*
>
> *Examples: scale 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; or, scale divisions may be 1/2, 1/4,
> 1/8, 1/16, etc.*
>
> *\[Nonretroactive as of January 1, 1986\]*
>
> ***S.1.2.1. Weight 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 of 1, 2, or 5.*
>
> *\[Nonretroactive as of January 1, 1989\]*
>
> (Added 1987)

## 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 [\<]{.underline} 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 being 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)
>
> **S.1.2.2.2. Class III and IIII.** 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.1.3. 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 percent 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.

> **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. 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 percent
> of the distance from weighbeam fulcrum to the weighbeam tip.
>
> **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. When 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
> subdivided 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 representations 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 any 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 traveling and remaining back of the zero
> graduation.

**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, a poise shall not be readily
> removable from a weigh­beam. The knife 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 graduations 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 total platform load (not
> counting the initial dead load that has been canceled by an initial
> zero-setting mechanism) is in excess of 105 percent 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.

> 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 weighbeams, nor (4) devices that
> indicate mathematically derived totalized values.
>
> *\[Nonretroactive as of January 1, 1993\]*
>
> (Amended 1990, 1992, and 1995)

**S.1.8. Computing Scales.**

> **S.1.8.1.M. 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 prices above \$7.50 per kilogram.

Value figures and graduations shall not be duplicated in any column or
row on the graduated chart. (See also S.1.8.2.)

> **S.1.8.1. Money-Value Graduations, Inch-Pound 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. (See also S.1.8.2.)

> **S.1.8.2. 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; G‑S.5.5.)
>
> **S.1.8.3. 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. Computing 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 terms 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 grams.

(Amended 1985 and 1995)

> ***S.1.8.3.1.** 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.1.8.4. 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,[^1]
>
> \(b\) the unit price,^1^
>
> \(c\) 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 element.
>
> (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.*
>
> *\[Nonretroactive as of January 1, 1995\]*
>
> 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.
>
> (Amended 1989, 1991 and 1993)

+-----------------------------+----------------------------------------+
| ***Table S.1.11. Categories |                                        |
| of Device and Methods of    |                                        |
| Sealing***                  |                                        |
+-----------------------------+----------------------------------------+
| ***Categories of Device***  | ***Method of Sealing***                |
+-----------------------------+----------------------------------------+
| *Category 1: No remote      | *Seal by physical seal or two event    |
| configuration capability.*  | counters: one for calibration          |
|                             | parameters and one for configuration   |
|                             | parameters.*                           |
+-----------------------------+----------------------------------------+
| *Category 2: Remote         | *The hardware enabling access for      |
| configuration capability,   | remote communication must be at the    |
| but access is controlled by | device and sealed using a physical     |
| physical hardware.*         | seal or two event counters: one for    |
|                             | calibration parameters and one for     |
| *Device shall clearly       | configuration parameters.*             |
| indicate that it is in the  |                                        |
| remote configuration mode   |                                        |
| and record such message if  |                                        |
| capable of printing in this |                                        |
| mode.*                      |                                        |
+-----------------------------+----------------------------------------+
| *Category 3: Remote         | *An event logger is required in the    |
| configuration capability    | device; it must include an event       |
| access may be unlimited or  | counter (000 to 999), the parameter    |
| controlled through a        | ID, the date and time of the change,   |
| software switch (e.g.,      | and the new value of the parameter. A  |
| password).*                 | 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 ten 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 1993)          |                                        |
+-----------------------------+----------------------------------------+

> ***S.1.12. Manual Gross Weight Entries. -** A device shall accept an
> entry of a manual weight value only when the scale is at gross load
> zero and the scale indication is zero in the gross weights display
> mode. 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
> the 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.*
>
> *\[Nonretroactive as of January 1, 1993\]*
>
> (Added 1992)
>
> **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.
>
> **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 and 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:
>
> \(a\) plus or minus 3 scale divisions for scales 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
>
> \(b\) plus or minus 1 scale division for all other scales.
>
> ***S.2.1.3. Scales Equipped with an Automatic Zero-Set­ting
> Mech­anism.** - 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:*
>
> *(a) for bench, counter, and livestock scales: 0.6 scale division;*
>
> *(b) for vehicle, axle-load, and railway track scales: 3.0 scale
> divi­sions; and*
>
> *(c) for all other scales: 1.0 scale division.*
>
> *\[Nonretroactive and enforceable as of January 1, 1981\]*
>
> ***S.2.1.3.1.** **Automatic Zero‑Setting Mechanism on Class III L
> Devices -** Class III L devices equipped with automatic zero setting
> mechanisms shall be designed with a sealable means to allow the
> automatic zero setting to be disabled during the inspection and test
> of the device.*
>
> *\[Nonretroactive as of January 1, 2001*\]
>
> (Added 1999)
>
> **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 percent 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. 

> \(a\) Scales of accuracy classes I, II, and III may be equipped with
> an initial zero-setting device.
>
> \(b\) An initial zero-setting mechanism shall not zero a load in
> excess of 20 percent 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.

(Added 1990)

> **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, provided 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 graduations 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), the value of the tare division shall be
> equal to the value of the scale division.\** 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 automatically clear any tare value
> shall also be designed to prevent the automatic clearing of tare until
> a complete transaction has been indicated.\**
>
> *(Amended 1985)*
>
> *\[Note: On a computing scale, this requires the input of a unit
> price, the display of the unit price, and a computed positive total
> price at a readable equi­librium. Other devices require a complete
> weighing operation, including tare, net, and gross weight
> determination\]\**
>
> *\[\*Nonretroactive as of January 1, 1983\]*
>
> **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
> percent of the scale capacity to within 0.02 percent of scale
> capacity. On a dynamic monorail weighing system, means shall be
> provided to automatically maintain this condition.

(Amended 1999)

> **S.2.4. Level-Indicating Means.** - Except for portable wheel-load
> weighers 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 moved from a level position and rebalanced in a position
> that is out of level in any upright direction by 5 percent
> (approximately 3 degrees). The level-­indicating means shall be
> readable without removing any scale parts requiring a tool.
>
> *\[This requirement is nonretroactive as of January 1, 1986, for
> prescription, jewelers\', and dairy-product-test scales and scales
> marked I and II\]*
>
> \[**Note:** Portable wheel-load weighers and portable axle-load scales
> shall be accurate when placed out of level up to and including 5
> percent (approximately 3 degrees).\]
>
> (Amended 1991)
>
> **S.2.4.1. Vehicle On-Board Weighing Systems.** - A vehicle on-board
> weighing system shall operate within tolerance when the weighing
> system is out of level up to 3 degrees or 5 percent. 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)
>
> **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:
>
> \(a\) plus or minus 3 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;
>
> \(b\) plus or minus 1 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 scale
> shall be equipped with appropriate means for arresting the oscillation
> of the mechanism.

**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 2.

**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 prevent 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 scale 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.*
>
> *\[Nonretroactive as of January 1, 1986\]*
>
> **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.\"[^2]
>
> (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 shall be:*

(a) *where N is the number of load cells in the scale for scales without
    lever systems:* $v_{\text{min}} \leq \frac{d}{\sqrt{N}}$

> *and,*
>
> *(b) for scales with lever systems:*
> $v_{\text{min}} \leq \frac{d}{\sqrt{N}\text{x }(\text{scale multiple})}$

*\[Nonretroactive as of January 1, 1994\]*

> *\[**Note:** When the value of the scale division, d, is different
> than the verification scale division, e, for the scale, the value of e
> must be used in the formulae above\]*
>
> *This requirement does not apply to complete scales and weighing
> elements which satisfy the following criteria:*
>
> *(1) The device has been evaluated for compliance with T.N.8.1.
> Temperature under the National Type Evaluation Program (NTEP);*
>
> *(2) The device has received an NTEP Certificate of Conformance; and*
>
> *(3) The device must be equipped with an automatic zero-setting
> mechanism which cannot be made inoperative in the normal weighing
> mode. (A test mode which permits the disabling of the automatic
> zero-setting mechanism is permissible, provided the scale cannot
> function normally while in this mode*.)

(Added 1993) (Amended 1996)

+-------------+-------------------------+-------------+--------------+
| #####       |                         |             |              |
| ### Table 3 |                         |             |              |
|             |                         |             |              |
| **          |                         |             |              |
| *Parameters |                         |             |              |
| for         |                         |             |              |
| Accuracy    |                         |             |              |
| Classes***  |                         |             |              |
+-------------+-------------------------+-------------+--------------+
| ***Class*** | ***Val­ue of the         | ***Nu­m­be­r   |              |
|             | veri­fi­ca­tion scale      | of­ scale^4^ |              |
|             | divi­sion***             | divi­sions   |              |
|             |                         | (n)***      |              |
|             | ***(d or e^1^)***       |             |              |
+-------------+-------------------------+-------------+--------------+
|             |                         | **          | *            |
|             |                         | *Mini­mum*** | **Maximum*** |
+-------------+-------------------------+-------------+--------------+
| ***SI       |                         |             |              |
| Units***    |                         |             |              |
+-------------+-------------------------+-------------+--------------+
| *I*         | *equal to or grea­t­er    | *50 000*    | *‑‑*         |
|             | than 1 mg*              |             |              |
+-------------+-------------------------+-------------+--------------+
| *II*        | *1 to 50 mg, inclusive* | *100*       | *100 000*    |
+-------------+-------------------------+-------------+--------------+
|             | *equal to or grea­t­er    | *5 000*     | *100 000*    |
|             | than 100 mg*            |             |              |
+-------------+-------------------------+-------------+--------------+
| *III^2^*    | *0.1 to 2 g, inclusive* | *100*       | *10 000*     |
+-------------+-------------------------+-------------+--------------+
|             | *equal to or grea­t­er    | *500*       | *10 000*     |
|             | than 5 g*               |             |              |
+-------------+-------------------------+-------------+--------------+
| *III L^3^*  | *equal to or grea­t­er    | *2 000*     | *10 000*     |
|             | than 2 kg*              |             |              |
+-------------+-------------------------+-------------+--------------+
| *IIII*      | *equal to or grea­t­er    | *100*       | *1 200*      |
|             | than 5 g*               |             |              |
+-------------+-------------------------+-------------+--------------+
| ####        |                         |             |              |
| ##### INCH‑ |                         |             |              |
| POUND Units |                         |             |              |
+-------------+-------------------------+-------------+--------------+
| *III*       | *0.0­002 lb to 0.005 lb, | *100*       | *10 000*     |
|             | inclusive*              |             |              |
+-------------+-------------------------+-------------+--------------+
|             | *0.005 oz to 0.125 oz,  | *100*       | *10 000*     |
|             | inclusive*              |             |              |
+-------------+-------------------------+-------------+--------------+
|             | *equal to or grea­t­er    | *500*       | *10 000*     |
|             | than 0.01 lb*           |             |              |
+-------------+-------------------------+-------------+--------------+
|             | *equal to or grea­t­er    | *500*       | *10 000*     |
|             | than 0.25 oz*           |             |              |
+-------------+-------------------------+-------------+--------------+
| *III L^3^*  | *equal to or grea­t­er    | *2 000*     | *10 000*     |
|             | than 5 lb*              |             |              |
+-------------+-------------------------+-------------+--------------+
| *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     |                         |             |              |
| dif         |                         |             |              |
| ferentiated |                         |             |              |
| by size,    |                         |             |              |
| shape, or   |                         |             |              |
| color), the |                         |             |              |
| value of    |                         |             |              |
| the         |                         |             |              |
| v           |                         |             |              |
| erification |                         |             |              |
| scale       |                         |             |              |
| division"e" |                         |             |              |
| is the      |                         |             |              |
| value of    |                         |             |              |
| the scale   |                         |             |              |
| division    |                         |             |              |
| immediately |                         |             |              |
| preceding   |                         |             |              |
| the         |                         |             |              |
| auxiliary   |                         |             |              |
| means.*     |                         |             |              |
|             |                         |             |              |
| *^2^ A      |                         |             |              |
| scale       |                         |             |              |
| marked "For |                         |             |              |
| p           |                         |             |              |
| rescription |                         |             |              |
| weighing    |                         |             |              |
| only" may   |                         |             |              |
| have a      |                         |             |              |
| scale       |                         |             |              |
| division    |                         |             |              |
| not less    |                         |             |              |
| than 0.01   |                         |             |              |
| g. (Added   |                         |             |              |
| 1986)*      |                         |             |              |
|             |                         |             |              |
| *^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 1      |                         |             |              |
| 000.*       |                         |             |              |
|             |                         |             |              |
| *^4^On a    |                         |             |              |
| multiple    |                         |             |              |
| range or    |                         |             |              |
| mul         |                         |             |              |
| ti-interval |                         |             |              |
| scale the   |                         |             |              |
| number of   |                         |             |              |
| divisions   |                         |             |              |
| for each    |                         |             |              |
| range       |                         |             |              |
| in          |                         |             |              |
| dependently |                         |             |              |
| 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         |                         |             |              |
| v           |                         |             |              |
| erification |                         |             |              |
| scale       |                         |             |              |
| division,   |                         |             |              |
| e, for each |                         |             |              |
| range. On a |                         |             |              |
| scale       |                         |             |              |
| system with |                         |             |              |
| multiple    |                         |             |              |
| load        |                         |             |              |
| receiving   |                         |             |              |
| elements    |                         |             |              |
| and         |                         |             |              |
| multiple    |                         |             |              |
| i           |                         |             |              |
| ndications, |                         |             |              |
| each        |                         |             |              |
| element     |                         |             |              |
| considered  |                         |             |              |
| shall not   |                         |             |              |
| in          |                         |             |              |
| dependently |                         |             |              |
| exceed 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.*     |                         |             |              |
+-------------+-------------------------+-------------+--------------+
| \[Non       |                         |             |              |
| retroactive |                         |             |              |
| as of       |                         |             |              |
| January 1,  |                         |             |              |
| 1986.\]     |                         |             |              |
| (Amended    |                         |             |              |
| 1986, 1987, |                         |             |              |
| 1997, 1998, |                         |             |              |
| and 1999)   |                         |             |              |
| (Footnote 4 |                         |             |              |
| Added 1997) |                         |             |              |
+-------------+-------------------------+-------------+--------------+

**S.6. Marking Requirements.** \[See also G-S.1., G‑S.4., G-S.6.,
G-S.7., G-UR.2.1.1., and UR.3.4.1.\]

> ***S.6.1. Nominal Capacity; Vehicle and Axle‑Load Scales. ‑** For all
> vehicle, 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 [\<]{.underline}
> CLC x (N ‑ 0.5)*
>
> *where N = the number of sections in the scale.*
>
> *(See N.1.3.4. and T.N.3.1.)*
>
> *\[Nonretroactive as of January 1, 1989\]*
>
> \[**Note:** When the device is used in a combination railway track and
> vehicle weighing application, the above formula shall apply only to
> the vehicle scale application.\]
>
> (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
> required in G-S.1. of the General Code and S.6. of the Scales 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 scales 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.
>
> (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, 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. and explained in the
> accompanying notes (Table S.6.3.b.)
>
> (Added 1990)
>
> **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
> nomencla­ture plate that is attached 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 section
> capacity.*
>
> *\[\*Nonretroactive as of January 1, 2002\]*
>
> (Amended 1988, 2001, and 2002)
>
> **S.6.5. Livestock Scales.** --A livestock 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 nomenclature plate
> that is attached 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 section capacity*\*.

*\[\*Nonretroactive as of January 1, 2003\]*

(Added 2002)

+---------------------+---------+------------+-----------+----+------+
| **Table S.6.3.a.**  |         |            |           |    |      |
|                     |         |            |           |    |      |
| **Marking           |         |            |           |    |      |
| Requirements**      |         |            |           |    |      |
+=====================+=========+============+===========+====+======+
| To Be Marked With   | W       |            |           |    |      |
| ****               | eighing |            |           |    |      |
|                     | Eq      |            |           |    |      |
|                     | uipment |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
|                     | We      | Indicating | Weighing  | Lo | O    |
|                     | ighing, | element    | and       | ad | ther |
|                     | l       | not        | load-     | ce | e    |
|                     | oad-rec | p          | receiving | ll | quip |
|                     | eiving, | ermanently | element   | wi | ­ment |
|                     | and     | attached   | not       | th | or   |
|                     | ind     | to         | pe        | CC | de   |
|                     | icating | weighing   | rmanent­ly |    | ­vice |
|                     | element | and        | attached  | \( |      |
|                     | in same | load       | to        | 11 | \(   |
|                     | housing | -receiving | i         | \) | 10\) |
|                     | or      | element or | ndicating |    |      |
|                     | covered | covered by | element   |    |      |
|                     | on the  | a separate | or        |    |      |
|                     | same    | CC         | covered   |    |      |
|                     | CC^1^   |            | by a      |    |      |
|                     |         |            | separate  |    |      |
|                     |         |            | CC        |    |      |
+---------------------+---------+------------+-----------+----+------+
| Manufacturer\'s ID  | x       | x          | x         | x  | x    |
| (1)                 |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Model Designation   | x       | x          | x         | x  | x    |
| and Prefix (1)      |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Serial Number and   | x       | x          | x         | x  | x    |
| Prefix (2)          |         |            |           |    | (16) |
+---------------------+---------+------------+-----------+----+------+
| Certificate of      | x       | x          | x         | x  | x    |
| Conformance Number  |         |            |           |    | (23) |
| (CC) (23)           |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Accuracy Class (17) | x       | x (8)      | x (19)    | x  |      |
+---------------------+---------+------------+-----------+----+------+
| Nominal Capacity    | x       | x          | x         |    |      |
| (3)(18)(20)         |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Value of Scale      | x       | x          |           |    |      |
| Division, \"d\" (3) |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Value of \"e\" (4)  | x       | x          |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Temperature Limits  | x       | x          | x         | x  |      |
| (5)                 |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Concentrated Load   |         | x          | x (9)     |    |      |
| Capacity (CLC)      |         |            |           |    |      |
| (12)(20)(22)        |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Special Application | x       | x          | x         |    |      |
| (13)                |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Maximum Number of   |         | x (8)      | x (19)    | x  |      |
| Scale Divisions     |         |            |           |    |      |
| (n~max~) (6)        |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Minimum             |         |            | x (19)    |    |      |
| Verification Scale  |         |            |           |    |      |
| Division (e~min~)   |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| \"S\" or \"M\" (7)  |         |            |           | x  |      |
+---------------------+---------+------------+-----------+----+------+
| Direction of        |         |            |           | x  |      |
| Loading (15)        |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Minimum Dead Load   |         |            |           | x  |      |
+---------------------+---------+------------+-----------+----+------+
| Maximum Capacity    |         |            |           | x  |      |
+---------------------+---------+------------+-----------+----+------+
| Safe Load Limit     |         |            |           | x  |      |
+---------------------+---------+------------+-----------+----+------+
| Load Cell           |         |            |           | x  |      |
| Verification        |         |            |           |    |      |
| Inter­val            |         |            |           |    |      |
|                     |         |            |           |    |      |
| (v~min~) (21)       |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| Section Capacity    |         | x          | x         |    |      |
| (14)(20)(22)        |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| **Note:** For       |         |            |           |    |      |
| applicable notes,   |         |            |           |    |      |
| see 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          |         |            |           |    |      |
| equipment that has  |         |            |           |    |      |
| no input or effect  |         |            |           |    |      |
| on device           |         |            |           |    |      |
| calibrations or     |         |            |           |    |      |
| configurations.     |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+
| (Added 1990)        |         |            |           |    |      |
| (Amended 1992,      |         |            |           |    |      |
| 1999, 2000, 2001    |         |            |           |    |      |
| and 2002) (Footnote |         |            |           |    |      |
| 1 Added 2001)       |         |            |           |    |      |
+---------------------+---------+------------+-----------+----+------+

+-----------------------------------------------------------------------+
| **Table S.6.3.b.**                                                    |
|                                                                       |
| **Notes For Table S.6.3.a.**                                          |
+=======================================================================+
| 1.  Manufacturer\'s identification and model designation and *model   |
|     designation prefix\**.                                            |
|                                                                       |
| \**\[Nonretroactive as of January 1, 2003*\]                          |
|                                                                       |
| > (See also G-S.1.) *\[Prefix lettering may be initial capitals, all  |
| > capitals or all lower case\]*                                       |
|                                                                       |
| (Amended 2000)                                                        |
|                                                                       |
| 2.  *Serial number \[Nonretroactive as of January 1, 1968\] and       |
|     prefix \[Nonretroactive as of January 1, 1986\].* (See also       |
|     G-S.1.)                                                           |
|                                                                       |
| 3.  The nominal capacity *and value of the scale division shall be    |
|     shown together (e.g., 50 000 x 5 kg, 100 000 x 10 lb, 15 x 0.005  |
|     kg , or 30 x 0.01 lb) adjacent to the weight display when the     |
|     nominal capacity and value of the scale division are not          |
|     immediately apparent. Each scale division value or weight unit    |
|     shall be marked on multiple range or multi‑interval scales.       |
|     \[Nonretroactive as of January 1, 1983\]*                         |
|                                                                       |
| 4.  *Required only if different from \"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). \[Nonretroactive as of         |
|     January 1, 1986\]*                                                |
|                                                                       |
| 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 which the device complies   |
|     with the applicable requirements for each accuracy class.         |
|     \[Nonretroactive as of January 1, 1988\]*                         |
|                                                                       |
| 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. 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  |
|     identified 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 customer restricting its use to that             |
|     application, e.g., postal scale, prepack scale, weight            |
|     classifier, etc.\** *When a scale is installed with an            |
|     operational counting feature, the scale shall be marked on both   |
|     the operator and customer side with the statement \"The counting  |
|     feature is not legal for trade.\"* *\[\*Nonretroactive as of      |
|     January 1, 1986\]*                                                |
|                                                                       |
| (Amended 1994)                                                        |
|                                                                       |
| 14. *Required on livestock\* and railway track scales. When marked on |
|     vehicle 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 \[Nonretroactive as of January 1, 1986\].* (See also       |
|     G-S.1.) 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.                                                   |
|                                                                       |
| 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 capacity 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 (weigh-bridge) of vehicle,     |
|         axle-load, and livestock scales.\**                           |
|                                                                       |
| *\[\*Nonretroactive as of January 1, 1989\]*                          |
|                                                                       |
| (Amended 1992)                                                        |
|                                                                       |
| 19. *\[Nonretroactive as of January, 1, 1988\]*                       |
|                                                                       |
| (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 (v~min~) 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.*                                             |
|                                                                       |
| *\[Nonretroactive as of January 1, 2003\]*                            |
|                                                                       |
| (Added 2002)                                                          |
|                                                                       |
| 23. *Required only if a CC has been issued for the device or          |
|     equipment.*                                                       |
|                                                                       |
| *\[Nonretroactive as of January 1, 2003\]*                            |
|                                                                       |
| (G-S.1. Identification (f) Added 2001)                                |
+-----------------------------------------------------------------------+

######  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 shall be equal to one‑half of the maximum load applied in the
> increasing‑load test. (See Table 6)
>
> (Amended 1998)
>
> **N.1.2.2. All Other Scales.** ‑ On all other scales, except for
> portable wheel load weighers, the decreas­ing‑load test 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. Bench or Counter Scales.** ‑ A shift test shall be
> conducted with a half‑capacity test load centered successively at four
> points equidis­tant between the center and the front, left, back, and
> right edges of the load‑receiving element.
>
> **N.1.3.2.  Dairy‑Product‑Test Scales.** ‑ A shift test shall be
> conducted with a test load of 18 grams successively positioned at all
> points on which a weight might reasonably be placed in the course of
> normal use of the scale.
>
> **N.1.3.3. Equal‑Arm Scales.** ‑ A shift test shall be conducted with
> a half‑cap­acity test load positioned on each pan as prescribed in
> N.1.3.1.  An equal test load shall be centered on the other pan.
>
> **N.1.3.4. Vehicle Scales, Axle-Load Scales, and Livestock Scales. -**
> At least one shift test shall be conducted with a minimum test load of
> 12.5 percent of scale capacity and may be performed anywhere on the
> load‑receiving element using the prescribed test patterns and maximum
> test loads specified below. (Two-section livestock scales shall be
> tested consistent with N.1.3.8.)
>
> (Amended 1991 and 2000)
>
> \(a\) **Prescribed Test Pattern.** - 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 platform, whichever is less.
> Multiple test patterns may be utilized when loaded in accordance with
> Paragraph (b).
>
> (Part (a) Amended 1997 and 2001)
>
> \(b\) **Maximum Loading.** - 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) x the
> width of the scale; for test patterns less than 1.2 m (4 ft) in length
> the maximum loading shall meet the formula: \[(wheel base of test cart
> or length of test load divided by 48 in) x 0.9 x CLC\]. The maximum
> test load applied to each test pattern shall not exceed the
> concentrated load 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. for the length of the area covered by the test load. For
> weighing 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 below.

<table>
<colgroup>
<col style="width: 9%" />
<col style="width: 6%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 8%" />
<col style="width: 6%" />
<col style="width: 9%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 8%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 9%" />
</colgroup>
<tbody>
<tr class="odd">
<td>4’</td>
<td colspan="2"></td>
<td>4’</td>
<td colspan="2"></td>
<td>4’</td>
<td colspan="2"></td>
<td>4’</td>
<td colspan="2"></td>
<td>4’</td>
</tr>
<tr class="even">
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td><p>Section</p>
<p>1</p></td>
<td></td>
<td colspan="3">Midway between sections 1 and 2</td>
<td></td>
<td><p>Section</p>
<p>2</p></td>
<td></td>
<td colspan="3">Midway between sections 2 and 3</td>
<td></td>
<td>Section 3</td>
</tr>
</tbody>
</table>

> (Part (b) Amended 1997)
>
> \(c\) **Multiple Pattern Loading.** - To test to the nominal capacity,
> multi­ple patterns may be simultaneously loaded in a manner consistent
> with the method of use.
>
> \(d\) **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)

**N.1.3.5.  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.

> **N.1.3.6.  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 1985)
>
> **N.1.3.6.1. Dynamic Monorail Weighing Systems.** - Dynamic tests with
> livestock carcasses should be conducted to duplicate actual use
> conditions. No less than 20 test loads using carcasses or portions of
> carcasses of the type normally weighed should be used in the dynamic
> test; two additional test loads may be included in the test run for
> use in the event that one or two test loads are rendered unusable
> during the dynamic test. Prior to starting the dynamic test, the test
> carcasses must be positioned far enough ahead of the scale so that
> their swaying motion settles to duplicate the normal sway of a
> continuously running plant chain. If the plant conveyer chain does not
> space or prevent the carcasses from touching one another, dynamic
> tests should not be conducted until this condition has been corrected.
>
> All 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 weighing the carcasses shall first be tested statically with test
> weights.)
>
> 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, static weights should be
> obtained before and after multiple dynamic tests. If the carcass
> changes weight between static tests, the amount of weight change
> should be taken into account, or the carcass should be disregarded for
> tolerance purposes.
>
> (**Note:** For a dynamic monorail test, the reference scale shall
> comply with the principles in the in the Fundamental Considerations
> Paragraph 3.2. Tolerances for Standards.)

(Added 1996) (Amended 1999)

> **N.1.3.7. 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 system is out of level to the
> extent that the weighing system remains operational.

(Added 1992)

> **N.1.3.8.  All Other Scales Except Crane Scales, Hanging Scales,
> Hopper Scales, Wheel‑Load Weighers, and Portable Axle‑Load Weighers.**
> ‑ A shift test shall be conducted with a half-capacity test load
> centered, as nearly as possible, successively at the center of each
> quarter of the load-receiving element, or with a quarter capacity test
> load centered, as nearly as possible, successively over each main load
> support.
>
> (Amended 1987)
>
> **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. or T.N.6.
>
> ***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 will not affect the results obtained.*
>
> *\[Nonretroactive as of January 1, 1986\]*
>
> (Added 1985)
>
> **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 than the minimum
> toler­ance applicable. (Also see G‑UR.4.2.) (Renumbered 1988)

**N.2. Verification (Testing) Standards.** ‑ Field standard weights used
in veri­fying weighing devices shall comply with requirements of NIST
Handbook 105‑1 (Class F) 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^2^.** ‑ The minimum test
weights and test loads for in‑service tests (except railway track
scales) are shown in Table 4. \[See Table 4 for footnote ^2^.\]

(Added 1984) (Amended 1988)

> **N.3.1. Minimum Test-Weight Load and Recommended Strain-Load Test for
> Railway Track Scales.**
>
> (Amended 1990)
>
> **N.3.1.1. Approval.** - 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)
>
> **N.3.1.2. Interim Approval.** - A test-weight load of not less than
> 13 500 kg (30 000 lb) and a strain-load test up to at least 25 percent
> of scale capacity may be used to return a scale into service following
> repairs.

(Added 1990)

> Note: The length of time the scale may be used following an interim
> test is at the discretion of the official with statutory authority.

(Added 1990)

> **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     |                    |         |                        |
| Loads^1^**   |                    |         |                        |
+--------------+--------------------+---------+------------------------+
| Device       | Minimums (in terms |         | (where practicable)    |
| capacity     | of device          |         |                        |
|              | capacity)          |         |                        |
+--------------+--------------------+---------+------------------------+
|              | Test weights       | Test    |                        |
|              | (greater of)       | l       |                        |
|              |                    | oads^2^ |                        |
+--------------+--------------------+---------+------------------------+
| 0 to 150 kg  | 100 %              |         |                        |
|              |                    |         |                        |
| (0 to        |                    |         |                        |
| 300 lb)      |                    |         |                        |
+--------------+--------------------+---------+------------------------+
| 151 to       | 25 % or 150 kg     | 75 %    | Test weights to dial   |
| 1 500 kg     | (300 lb)           |         | face ca­paci­ty,         |
|              |                    |         | 1 000 d, or test load  |
| (301 to      |                    |         | to used ca­pacity, if   |
| 3 000 lb)    |                    |         | great­er than mini­mums  |
|              |                    |         | speci­fied              |
|              |                    |         |                        |
|              |                    |         | During initial         |
|              |                    |         | verification, a scale  |
|              |                    |         | should be tested to    |
|              |                    |         | capacity.              |
+--------------+--------------------+---------+------------------------+
| 1 501 to     | 12.5 % or 500 kg   | 50 %    |                        |
| 20 000 kg    | (1 000 lb)         |         |                        |
|              |                    |         |                        |
| (3 001 to    |                    |         |                        |
| 40 000 lb)   |                    |         |                        |
+--------------+--------------------+---------+------------------------+
| 20 001 kg+   | 12.5 % or 5 000 kg | 25 %^3^ |                        |
|              | (10 000 lb)        |         |                        |
| (40 001 lb+) |                    |         |                        |
+--------------+--------------------+---------+------------------------+
| ^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 will 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        |                    |         |                        |
| s            |                    |         |                        |
| ubstitutions |                    |         |                        |
| 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     |                    |         |                        |
| practical, a |                    |         |                        |
| strain load  |                    |         |                        |
| test should  |                    |         |                        |
| be conducted |                    |         |                        |
| to the used  |                    |         |                        |
| capacity of  |                    |         |                        |
| the scale.   |                    |         |                        |
| When a       |                    |         |                        |
| strain load  |                    |         |                        |
| test is      |                    |         |                        |
| conducted,   |                    |         |                        |
| the          |                    |         |                        |
| tolerance    |                    |         |                        |
| applies only |                    |         |                        |
| to the known |                    |         |                        |
| test load.   |                    |         |                        |
|              |                    |         |                        |
| (Amended     |                    |         |                        |
| 1988, 1989   |                    |         |                        |
| and 1994)    |                    |         |                        |
+--------------+--------------------+---------+------------------------+

**N.4. Coupled-in-Motion Railroad Weighing Systems**[^3]

> **N.4.1. Weighing Systems Used to Weigh Trains of Less Than 10
> 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 10 or More Cars.** - The minimum test train
shall be a consecutive-car test train of no less than 10 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 Service on or After January 1,
> 1991, and Used to Weigh Trains of 10 or More Cars.** --
>
> \(a\) These weighing systems shall be tested using a consecutive-car
> test train of no less than 10 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:
>
> \(1\) a consecutive-car test train of a length typical of train(s)
> normally weighed; or
>
> \(2\) a 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 specified
in N.4.3.1.1.

> 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)
>
> **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) normally 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 percent. If
> the difference in test results exceeds 0.15 percent, the length of the
> shorter consecu­tive-car test train shall be increased until agree­ment
> within 0.15 percent is achieved. Any adjustments to the weighing
> system based upon the use of a shorter consecutive-car test train
> shall be offset to correct 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 10 cars or 10 percent 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 10 cars.
>
> \(b\) If the consecutive-car test train consists of between 10 cars
> and 20 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 20 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)

**N.6. Nominal Capacity of Prescription Scales.** ‑ The nominal capacity
of a prescription scale shall be assumed to be 1/2 apothecary ounce,
unless otherwise marked.  (Applicable only to scales not marked with an
accuracy class.)

# T.  Tolerances Applicable to Devices

**[not]{.underline} 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.
>
> (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. and Table 5.
>
> (Amended 1990)

**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.
> through T.2.8.:  2 d, 0.2 percent 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
> percent 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).

+-------------+--------+--------+-------+-------+-------+------------+
| **Table     |        |        |       |       |       |            |
| T.1.1.      |        |        |       |       |       |            |
| Tolerances  |        |        |       |       |       |            |
| for         |        |        |       |       |       |            |
| Unmarked    |        |        |       |       |       |            |
| Scales**    |        |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Type of     | Subca  | Min.   | Ac    | M     | Decre | Other      |
| Device      | tegory | Tol.   | cept. | aint. | asing | Applicable |
|             |        |        | Tol.  | Tol.  | -Load | Re         |
|             |        |        |       |       |       | quirements |
|             |        |        |       |       | Mul   |            |
|             |        |        |       |       | tipli |            |
|             |        |        |       |       | er^1^ |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Vehicle,    |        | Class  |       |       | 1.0   | T.N.2.,    |
| axle-load,  |        | III L, |       |       |       | T.N.3.,    |
| livestock,  |        | T      |       |       |       | T.N.4.1.,  |
| railway     |        | .N.3.1 |       |       |       | T.N.4.2.,  |
| track       |        | (Table |       |       |       | T.N.4.3.,  |
| (weighing   |        | 6) and |       |       |       | T.N.4.4.,  |
| s           |        | T.     |       |       |       | T.N.5.,    |
| tatically), |        | N.3.2. |       |       |       | T.N.7.2.   |
| crane, and  |        |        |       |       |       |            |
| hopper      |        |        |       |       |       |            |
| (other than |        |        |       |       |       |            |
| grain       |        |        |       |       |       |            |
| hopper)     |        |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Grain test  | n     | Class  |       |       | 1.0   |            |
| scales      | 10 000 | III,   |       |       |       |            |
|             |        | T.     |       |       |       |            |
|             | n \>   | N.3.1. |       |       |       |            |
|             | 10 000 | (Table |       |       |       |            |
|             |        | 6) and |       |       |       |            |
|             |        | T.     |       |       |       |            |
|             |        | N.3.2. |       |       |       |            |
|             |        |        |       |       |       |            |
|             |        | Class  |       |       |       |            |
|             |        | II,    |       |       |       |            |
|             |        | T.     |       |       |       |            |
|             |        | N.3.1. |       |       |       |            |
|             |        | (Table |       |       |       |            |
|             |        | 6) and |       |       |       |            |
|             |        | T.     |       |       |       |            |
|             |        | N.3.2. |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Railway     |        | T.     |       |       | 1.0   |            |
| track       |        | N.3.6. |       |       |       |            |
| scales      |        | except |       |       |       |            |
| weighing in |        | that   |       |       |       |            |
| motion      |        | for    |       |       |       |            |
|             |        | T.N.   |       |       |       |            |
|             |        | 3.6.2. |       |       |       |            |
|             |        | (a),   |       |       |       |            |
|             |        | no     |       |       |       |            |
|             |        | single |       |       |       |            |
|             |        | error  |       |       |       |            |
|             |        | shall  |       |       |       |            |
|             |        | exceed |       |       |       |            |
|             |        | four   |       |       |       |            |
|             |        | times  |       |       |       |            |
|             |        | the    |       |       |       |            |
|             |        | maint  |       |       |       |            |
|             |        | enance |       |       |       |            |
|             |        | tole   |       |       |       |            |
|             |        | rance. |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Monorail    |        | T.     |       |       | 1.0   |            |
| Scales,     |        | N.3.8. |       |       |       |            |
| In-Motion   |        |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Custom      |        | ± 5 %  |       |       | 1.0   |            |
| er-Operated |        | of     |       |       |       |            |
| Bu          |        | a      |       |       |       |            |
| lk-Weighing |        | pplied |       |       |       |            |
| Systems for |        | ma     |       |       |       |            |
| Recycled    |        | terial |       |       |       |            |
|             |        | test   |       |       |       |            |
| Materials   |        | load.  |       |       |       |            |
|             |        |        |       |       |       |            |
|             |        | A      |       |       |       |            |
|             |        | verage |       |       |       |            |
|             |        | error  |       |       |       |            |
|             |        | on 10  |       |       |       |            |
|             |        | or     |       |       |       |            |
|             |        | more   |       |       |       |            |
|             |        | test   |       |       |       |            |
|             |        | loads  |       |       |       |            |
|             |        |       |       |       |       |            |
|             |        | 2.5 %. |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Wheel-load  | Tested | 0.5 d  | 1 %   | 2 %   | 1     |            |
| weighers    | indivi | or 50  | of    | of    | .5^3^ |            |
| and         | dually | lb,    | test  | test  |       |            |
| portable    | or in  | whi    | load  | load  |       |            |
| axle-load   | pa     | chever |       |       |       |            |
| scales      | irs^2^ | is     |       |       |       |            |
|             |        | g      |       |       |       |            |
|             |        | reater |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| P           |        | 0.1    | 0.1 % | 0.1 % | 1.5   |            |
| rescription |        | grain  | of    | of    |       |            |
| scales      |        | (6 mg) | test  | test  |       |            |
|             |        |        | load  | load  |       |            |
|             |        |        | load  |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Jewelers\'  | Gra    | 0.5 d  | 0     | 0     | 1.5   |            |
| scales      | duated |        | .05 % | .05 % |       |            |
|             |        |        | of    | of    |       |            |
|             |        |        | test  | test  |       |            |
|             |        |        | load  | load  |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
|             | Ungra  | Sensi  |       |       |       |            |
|             | duated | tivity |       |       |       |            |
|             |        | or     |       |       |       |            |
|             |        | sm     |       |       |       |            |
|             |        | allest |       |       |       |            |
|             |        | w      |       |       |       |            |
|             |        | eight, |       |       |       |            |
|             |        | whi    |       |       |       |            |
|             |        | chever |       |       |       |            |
|             |        | is     |       |       |       |            |
|             |        | less   |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Dairy-p     | Loads  | 0.2    | 0.2   | 0.2   | 1.5   |            |
| roduct-test | \< 18  | grain  | grain | grain |       |            |
| scale       | g      |        |       |       |       |            |
|             |        | 0.2    | 0.3   | 0.5   |       |            |
|             | 18 g   | grain  | grain | grain |       |            |
|             | load   |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Postal and  | Loads  | 15     | 15    | 15    | 1.5   |            |
| parcel post | \<     | grain, | g     | g     |       |            |
| scales      | 2 lb   | 1 g,   | rain, | rain, |       |            |
| De          |        | 1/     | 1 g,  | 1 g,  |       |            |
| signed/used |        | 32 oz, | 1/3   | 1/3   |       |            |
| to weigh    |        | 0.03   | 2 oz, | 2 oz, |       |            |
|             |        | oz, or | 0.03  | 0.03  |       |            |
| loads       |        | 0.002  | oz,   | oz,   |       |            |
| \< 2 lb     |        | lb     | or    | or    |       |            |
|             |        |        | 0.002 | 0.002 |       |            |
|             |        |        | lb    | lb    |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
|             | Loads  | Table  | Table | Table |       |            |
|             |  2 lb | 5      | 5     | 5     |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| Other       |        | Table  | Table | Table | 1.5   |            |
| postal and  |        | 5      | 5     | 5     |       |            |
| parcel post |        |        |       |       |       |            |
| scales      |        |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| All other   | n \>   | 0.5d   | 0     | 0.1 % | 1.5   | T.N.2.5.,  |
| scales      | 5000   | or     | .05 % | of    |       | T.N.4.1.,  |
|             |        | 0.05 % | of    | test  |       | T.N.4.2.,  |
|             |        | of     | test  | load  |       | T.N.4.3.,  |
|             |        | scale  | load  |       |       | T.N.5.,    |
|             |        | cap    |       |       |       | T.N.7.2.   |
|             |        | acity, |       |       |       |            |
|             |        | whi    |       |       |       |            |
|             |        | chever |       |       |       |            |
|             |        | is     |       |       |       |            |
|             |        | less   |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
|             | n     | Class  |       |       | 1.0   | T.N.2.,    |
|             | 5000   | III,   |       |       |       | T.N.3.,    |
|             |        | T.N    |       |       |       | T.N.4.1.,  |
|             |        | .3.1., |       |       |       | T.N.4.2.,  |
|             |        | Table  |       |       |       | T.N.4.3.,  |
|             |        | 6 and  |       |       |       | T.N.5.,    |
|             |        | T.     |       |       |       | T.N.7.2.   |
|             |        | N.3.2. |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+
| ^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         |        |        |       |       |       |            |
| i           |        |        |       |       |       |            |
| ndications. |        |        |       |       |       |            |
| (Table      |        |        |       |       |       |            |
| Added 1990; |        |        |       |       |       |            |
| Amended     |        |        |       |       |       |            |
| 1992 and    |        |        |       |       |       |            |
| 1993)       |        |        |       |       |       |            |
|             |        |        |       |       |       |            |
| > ^3^ The   |        |        |       |       |       |            |
| >           |        |        |       |       |       |            |
|  decreasing |        |        |       |       |       |            |
| > load test |        |        |       |       |       |            |
| > does not  |        |        |       |       |       |            |
| > apply to  |        |        |       |       |       |            |
| > portable  |        |        |       |       |       |            |
| > wheel     |        |        |       |       |       |            |
| > load      |        |        |       |       |       |            |
| > weighers. |        |        |       |       |       |            |
+-------------+--------+--------+-------+-------+-------+------------+

+-----------+----------------+---------+---------+---------+----------+
| **Table   |                |         |         |         |          |
| 5.**      |                |         |         |         |          |
|           |                |         |         |         |          |
| **Ma      |                |         |         |         |          |
| intenance |                |         |         |         |          |
| and       |                |         |         |         |          |
| A         |                |         |         |         |          |
| cceptance |                |         |         |         |          |
| T         |                |         |         |         |          |
| olerances |                |         |         |         |          |
| for       |                |         |         |         |          |
| U         |                |         |         |         |          |
| nmarked** |                |         |         |         |          |
|           |                |         |         |         |          |
| **Postal  |                |         |         |         |          |
| and       |                |         |         |         |          |
| Parcel    |                |         |         |         |          |
| Post      |                |         |         |         |          |
| Scales**  |                |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+
| Scale     | Test loads     | Mai­n    |         | Ac­c     |          |
| ca­paci­ty  |                | te­n­ance |         | ep­tance |          |
|           |                | to      |         | to      |          |
|           |                | ler­ance |         | ler­ance |          |
|           |                |         |         |         |          |
|           |                | (±)     |         | (±)     |          |
+-----------+----------------+---------+---------+---------+----------+
| (lb)      | (lb)           | (oz)    | (lb)    | (oz)    | (lb)     |
+-----------+----------------+---------+---------+---------+----------+
| 0 to 4,   | 0 to 1,        | 1/32    | 0.002   | 1/32    | 0.002    |
| in        | in­clu­sive      |         |         |         |          |
| ­clu­sive\* |                |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+
|           | over 1         | 1/8     | 0.008   | 1/16    | 0.004    |
+-----------+----------------+---------+---------+---------+----------+
| over 4\*  | 0 to 7,        | 3/16    | 0.012   | 3/16    | 0.012    |
|           | in­clu­sive      |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+
|           | 7+ to 24,      | 3/8     | 0.024   | 3/16    | 0.012    |
|           | in­clu­sive      |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+
|           | 24+ to 30,     | 1/2     | 0.030   | 1/4     | 0.015    |
|           | in­clu­sive      |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+
|           | over 30        | 0.1 %   |         | 0.05 %  |          |
|           |                | of Test |         | of Test |          |
|           |                | Load    |         | Load    |          |
+-----------+----------------+---------+---------+---------+----------+
| \*See     |                |         |         |         |          |
| Table     |                |         |         |         |          |
| T.1.1.    |                |         |         |         |          |
| for       |                |         |         |         |          |
| scales    |                |         |         |         |          |
| designed  |                |         |         |         |          |
| and/or    |                |         |         |         |          |
| used to   |                |         |         |         |          |
| weigh     |                |         |         |         |          |
| loads     |                |         |         |         |          |
| less than |                |         |         |         |          |
| 2 lb.     |                |         |         |         |          |
+-----------+----------------+---------+---------+---------+----------+

> **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
> percent of the scale capacity, whichever is less.

**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. 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 the 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.4. Radio Frequency Interference (RFI) and Other Electro­magnetic
Interference Susceptibility.**  ‑ The difference between the weight
indica­tion with 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 indicator 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.

(Added 1986)

***T.5. 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.*

*\[Nonretro­active and effective January 1, 1981\]*

(Added 1986)

**T.N. Tolerances Applicable to Devices**

**Marked I, II, III, III L, & 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 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.

**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; the tolerance values apply to certified test loads
> only.­
>
> **T.N.2.2.  Type Evaluation Examinations.** ‑ For type evaluation
> examinations, the tolerance values apply to increasing 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.)
>
> **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
> tolerance values are as specified in Table 6.
>
> **T.N.3.2.  Acceptance Tolerance Values.** ‑ The acceptance toler­ance
> values shall be one‑half the maintenance 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. and T.N.3.2.
>
> (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. and T.N.3.2. 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 percent of the scale capacity, whichever is less.
>
> (Amended 1986)

+-------+-----------+-------+-------+---------+---------+------------+
| **    |           |       |       |         |         |            |
| Table |           |       |       |         |         |            |
| 6.**  |           |       |       |         |         |            |
|       |           |       |       |         |         |            |
| **M   |           |       |       |         |         |            |
| ainte |           |       |       |         |         |            |
| nance |           |       |       |         |         |            |
| To    |           |       |       |         |         |            |
| leran |           |       |       |         |         |            |
| ces** |           |       |       |         |         |            |
|       |           |       |       |         |         |            |
| *     |           |       |       |         |         |            |
| *(All |           |       |       |         |         |            |
| v     |           |       |       |         |         |            |
| alues |           |       |       |         |         |            |
| in    |           |       |       |         |         |            |
| this  |           |       |       |         |         |            |
| table |           |       |       |         |         |            |
| are   |           |       |       |         |         |            |
| in    |           |       |       |         |         |            |
| scale |           |       |       |         |         |            |
| di    |           |       |       |         |         |            |
| visio |           |       |       |         |         |            |
| ns)** |           |       |       |         |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| Tole  |           |       |       |         |         |            |
| rance |           |       |       |         |         |            |
| in    |           |       |       |         |         |            |
| scale |           |       |       |         |         |            |
| divi  |           |       |       |         |         |            |
| sions |           |       |       |         |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
|       | 1         | 2     |       | 3       |         | 5          |
+-------+-----------+-------+-------+---------+---------+------------+
| Class | Test Load |       |       |         |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| I     | 0 ‑ 50    | 50    | 200   | 20­0 001 |         |            |
|       | 000       | 001 ‑ | 000   | +       |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| II    | 0 ‑  5    | 5 001 | 20    | 20 001  |         |            |
|       | 000       | ‑     | 000   | +       |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| III   | 0 -       | 501 ‑ | 2 000 | 2 001 ‑ | 4 000   | 4 001 +    |
|       | 500       |       |       |         |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| IIII  | 0 -       | 51 ‑  | 200   | 201 ‑   | 400     | 401 +      |
|       | 50        |       |       |         |         |            |
+-------+-----------+-------+-------+---------+---------+------------+
| III L | 0 ‑       | 501 ‑ | 1 000­ | (Add 1d |         |            |
|       |  500      |       |       | for     |         |            |
|       |           |       |       | each    |         |            |
|       |           |       |       | add     |         |            |
|       |           |       |       | itional |         |            |
|       |           |       |       | 500 d   |         |            |
|       |           |       |       | or      |         |            |
|       |           |       |       | f       |         |            |
|       |           |       |       | rac­tion |         |            |
|       |           |       |       | t       |         |            |
|       |           |       |       | here­of) |         |            |
+-------+-----------+-------+-------+---------+---------+------------+

> **T.N.3.5.  Separate Main Elements:  Load Transmitting Ele­ment,
> In­dicating Element, Etc.** ‑ If a main element separate from a
> weighing device is submitted for type evaluation, the tolerance for
> the element is 0.7 that for the complete weighing device. This
> fraction includes the tolerance attributable to the testing devices
> used.
>
> **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 following
> 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 percent.

(Amended 1990)

> **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 percent of the errors may exceed two times the
> static main­tenance tolerance; and
>
> \(c\) not more than 35 percent 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 error 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. On a
> dynamic test of 20 or more individual test loads, 10 percent of the
> individual test loads may be in error, each not to exceed two times
> the tolerance. The error on the total of the individual test loads
> shall not exceed ± 0.2 percent. (See also Note in N.1.3.6.1.) *For
> equipment undergoing type evaluation, a tolerance equal to one‑half
> the maintenance tolerance values shown in Table 6 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 percent of the applied materials test load except that
> the average error on 10 or more test materials test loads shall not
> exceed ± 2.5 percent.

(Added 1986)

**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, weighbeam 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 the 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 conduct 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.** ‑ At constant test conditions, the
> indication 20 seconds after the application of a load and the
> indication after 1 hour shall not differ by more than:
>
> **(a)** one-half of the absolute value of the applicable tolerance for
> the applied load for class III L devices; and
>
> **(b)** the absolute value of the applicable tolerance for the applied
> load for all other devices.
>
> (Amended 1989)

**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 shall be within applicable tolerances.

**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 in­dicators, and 2 d or 0.2 percent 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 division 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. (See N.1.5.)
>
> **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.  (See N.1.5.1.)

**T.N.8. 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
>
> \(c\) 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.

+-----------------------------------+----------------------------------+
| **Table T.N.8.1.2.**              |                                  |
|                                   |                                  |
| **Temperature Range by Class**    |                                  |
+-----------------------------------+----------------------------------+
| Class                             | Temperature ­Range                |
+-----------------------------------+----------------------------------+
| I                                 | 5 C (9 °F)                      |
+-----------------------------------+----------------------------------+
| II                                | 15 C (27 °F)                    |
+-----------------------------------+----------------------------------+
| III, III L, & IIII                | 30 C (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 the 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. through
> T.N.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.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.

**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. 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 during the
disturbance. \[Editors\' Note: Following the 1997 NCWM Annual Meeting,
the text in this paragraph was revised with concurrence of the S&T
Committee to clarify its application.\]

(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.[^4]

**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.

(b) For devices not marked with a class designation, Table 7b applies.

+------+---------------------------------------------------------------+
| **T  |                                                               |
| able |                                                               |
| 7    |                                                               |
| a.** |                                                               |
|      |                                                               |
| *    |                                                               |
| *Typ |                                                               |
| ical |                                                               |
| C    |                                                               |
| lass |                                                               |
| or   |                                                               |
| Type |                                                               |
| of   |                                                               |
| De   |                                                               |
| vice |                                                               |
| for  |                                                               |
| Weig |                                                               |
| hing |                                                               |
| Oper |                                                               |
| atio |                                                               |
| ns** |                                                               |
+------+---------------------------------------------------------------+
| C    | Weighing Application or Scale Type                            |
| lass |                                                               |
+------+---------------------------------------------------------------+
| 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, animal scales, postal scales, scales used to        |
|      | deter­mine laun­dry charges, and vehicle on-board weighing      |
|      | systems                                                       |
+------+---------------------------------------------------------------+
| III  | Vehicle, axle‑load, livestock, railway track scales, crane,   |
| L    | hopper (other than grain hop­per) scales, and vehicle on-board |
|      | weighing systems                                              |
+------+---------------------------------------------------------------+
| IIII | Wheel-load weighers and portable axle-load weighers used for  |
|      | highway weight enforcement                                    |
+------+---------------------------------------------------------------+
| N    |                                                               |
| ote: |                                                               |
| A    |                                                               |
| s    |                                                               |
| cale |                                                               |
| with |                                                               |
| a    |                                                               |
| hi   |                                                               |
| gher |                                                               |
| accu |                                                               |
| racy |                                                               |
| c    |                                                               |
| lass |                                                               |
| than |                                                               |
| that |                                                               |
| s    |                                                               |
| peci |                                                               |
| fied |                                                               |
| as   |                                                               |
| \"t  |                                                               |
| ypic |                                                               |
| al\" |                                                               |
| may  |                                                               |
| be   |                                                               |
| u    |                                                               |
| sed. |                                                               |
|      |                                                               |
| (Ame |                                                               |
| nded |                                                               |
| 1    |                                                               |
| 985, |                                                               |
| 1    |                                                               |
| 986, |                                                               |
| 1    |                                                               |
| 987, |                                                               |
| 1    |                                                               |
| 988, |                                                               |
| 1    |                                                               |
| 992, |                                                               |
| and  |                                                               |
| 1    |                                                               |
| 995) |                                                               |
+------+---------------------------------------------------------------+

+--------------------------------+-------------------------------------+
| **Table 7b.**                  |                                     |
|                                |                                     |
| **Applicable to Devices not    |                                     |
| Marked With a Class            |                                     |
| Designation**                  |                                     |
+--------------------------------+-------------------------------------+
| Scale Type or De­sign           | Maximum Value of d                  |
+--------------------------------+-------------------------------------+
| Retail Food Scales, 50‑lb      | 1 ounce                             |
| capacity and less              |                                     |
+--------------------------------+-------------------------------------+
| Ani­mal Scales                  | 1 pound                             |
+--------------------------------+-------------------------------------+
| Grain Hop­per Scales            | 10 pounds (not greater than 0.05 %  |
|                                | of c­apa­city)                        |
| Ca­paci­ty up to and incl. 50    |                                     |
| 000 lb                         | 20 pounds                           |
|                                |                                     |
| Ca­paci­ty over 50 000 lb        |                                     |
+--------------------------------+-------------------------------------+
| Crane Scales                   | not greater than 0.2 % of ca­pac­ity  |
+--------------------------------+-------------------------------------+
| Vehi­cle and A­xle‑­Load Scales   | 20 pounds                           |
| Used in Combination            |                                     |
|                                | 50 pounds                           |
| Ca­paci­ty up to and in­clud­ing   |                                     |
| 200 000 lb                     |                                     |
|                                |                                     |
| Ca­paci­ty over 200 000 lb       |                                     |
+--------------------------------+-------------------------------------+
| Railway Track Scales           | 20 pounds                           |
|                                |                                     |
| With wei­gh­b­eam                 | 100 pounds                          |
|                                |                                     |
| Au­to­mat­ic indi­cat­ing           |                                     |
+--------------------------------+-------------------------------------+
| Scales with ca­paci­ties gre­ater | 0.1 % capacity (but not greater     |
| than 500 lb ex­cept oth­er­wise   | than 50 lb)                         |
| spe­ci­fied                      |                                     |
+--------------------------------+-------------------------------------+
| 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.** ‑ The minimum number of scale
> divisions for a Class III Hopper Scale used for weighing grain shall
> be 2000.
>
> ***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 1995) (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.*
>
> *\[Nonretroactive as of January 1, 1986\]*
>
> (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,
> and 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 provide 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 scale. *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.*
>
> *\[Non­retroactive as of January 1, 1973\]*
>
> **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 ends of a
> vehicle scale installed in any one location for a period of 6 months
> or more, 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 constructed of concrete 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. Any slope in the remaining
> portion of the approach shall ensure (1) ease of vehicle access, (2)
> ease for testing purposes, and (3) drainage away from the scale.*
>
> *\[Nonretroactive as of 1976\]*
>
> (Amended 1977, 1983, and 1993)
>
> **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 is 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.1.3.6.1. (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.

+---------------------+-----------------------+------------------------+
| **Table 8.**        |                       |                        |
|                     |                       |                        |
| **Recommended       |                       |                        |
| Minimum Load**      |                       |                        |
+---------------------+-----------------------+------------------------+
| Class               | Value of scale        | Re­com­men­ded mini­mum    |
|                     | divi­sion              | load                   |
|                     |                       |                        |
|                     | (d or e\*)            | (d or e\*)             |
+---------------------+-----------------------+------------------------+
| I                   | equal to or gre­ater   | 100                    |
|                     | than 0.001 g          |                        |
+---------------------+-----------------------+------------------------+
| II                  | 0.001 g to 0.05 g,    | 20                     |
|                     | in­clu­sive             |                        |
+---------------------+-----------------------+------------------------+
|                     | equal to or gre­ater   | 50                     |
|                     | than 0.1 g            |                        |
+---------------------+-----------------------+------------------------+
| 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
> determining 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.

(Added 1996)

> **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 vehicle 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:

\(a\) the weight of 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

> \(b\) the weight of 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 determination 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) shall not be used
> for other than its in­tended purpose[^5].
>
> **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;

\(b\) 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 and 1992)
>
> **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 Gross Weight Entries.** - Manual gross weight
> entries are permitted for use in the following applications only: (1)
> when credit is given for a weighed item on point-of-sale systems
> interfaced with scales; (2) when a device or system generates labels
> for standard weight packages; (3) when postal scales or weight
> classifiers generate manifests for packages to be picked up at a later
> time; or (4) when livestock and vehicle scale systems generate weight
> tickets to correct erroneous tickets.
>
> (Added 1992) (Amended 2000)
>
> **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.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 element 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
> scale.
>
> (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, with
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. Except as provided in N.4.2. and
N.4.3.(a), normal 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 facility, and
should be considered prior to installation.

(Added 1990) (Amended 1992)

+------------+------+------+------+------+------+------+------+------+
| **Table    |      |      |      |      |      |      |      |      |
| U          |      |      |      |      |      |      |      |      |
| R.3.2.1.** |      |      |      |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
| **Span     |      |      |      |      |      |      |      |      |
| Maximum    |      |      |      |      |      |      |      |      |
| Load**     |      |      |      |      |      |      |      |      |
+============+======+======+======+======+======+======+======+======+
| **Distance | **R  |      |      |      |      |      |      |      |
| in feet    | atio |      |      |      |      |      |      |      |
| between    | of   |      |      |      |      |      |      |      |
| the        | CLC  |      |      |      |      |      |      |      |
| extremes   | to   |      |      |      |      |      |      |      |
| of any two | max  |      |      |      |      |      |      |      |
| or more    | imum |      |      |      |      |      |      |      |
| c          | Load |      |      |      |      |      |      |      |
| onsecutive | ("r" |      |      |      |      |      |      |      |
| axles**    | fac  |      |      |      |      |      |      |      |
|            | tor) |      |      |      |      |      |      |      |
|            | car  |      |      |      |      |      |      |      |
|            | ried |      |      |      |      |      |      |      |
|            | on   |      |      |      |      |      |      |      |
|            | a    |      |      |      |      |      |      |      |
|            | ny** |      |      |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            | **g  |      |      |      |      |      |      |      |
|            | roup |      |      |      |      |      |      |      |
|            | of 2 |      |      |      |      |      |      |      |
|            | or   |      |      |      |      |      |      |      |
|            | more |      |      |      |      |      |      |      |
|            | con  |      |      |      |      |      |      |      |
|            | secu |      |      |      |      |      |      |      |
|            | tive |      |      |      |      |      |      |      |
|            | axle |      |      |      |      |      |      |      |
|            | s.** |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
|            | **2  | **3  | **4  | **5  | **6  | **7  | **8  | **9  |
|            | axl  | axl  | axl  | axl  | axl  | axl  | axl  | axl  |
|            | es** | es** | es** | es** | es** | es** | es** | es** |
+------------+------+------+------+------+------+------+------+------+
| 4**^1^**   | 1    |      | I    |      |      |      |      |      |
|            | .000 |      | NSTR |      |      |      |      |      |
|            |      |      | UCTI |      |      |      |      |      |
|            |      |      | ONS: |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            |      |      | 1\.  |      |      |      |      |      |
|            |      |      | D    |      |      |      |      |      |
|            |      |      | eter |      |      |      |      |      |
|            |      |      | mine |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | sca  |      |      |      |      |      |
|            |      |      | le's |      |      |      |      |      |
|            |      |      | CLC. |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            |      |      | 2\.  |      |      |      |      |      |
|            |      |      | C    |      |      |      |      |      |
|            |      |      | ount |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | nu   |      |      |      |      |      |
|            |      |      | mber |      |      |      |      |      |
|            |      |      | of   |      |      |      |      |      |
|            |      |      | a    |      |      |      |      |      |
|            |      |      | xles |      |      |      |      |      |
|            |      |      | on   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | veh  |      |      |      |      |      |
|            |      |      | icle |      |      |      |      |      |
|            |      |      | in a |      |      |      |      |      |
|            |      |      | g    |      |      |      |      |      |
|            |      |      | iven |      |      |      |      |      |
|            |      |      | span |      |      |      |      |      |
|            |      |      | and  |      |      |      |      |      |
|            |      |      | d    |      |      |      |      |      |
|            |      |      | eter |      |      |      |      |      |
|            |      |      | mine |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | dist |      |      |      |      |      |
|            |      |      | ance |      |      |      |      |      |
|            |      |      | in   |      |      |      |      |      |
|            |      |      | feet |      |      |      |      |      |
|            |      |      | bet  |      |      |      |      |      |
|            |      |      | ween |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | f    |      |      |      |      |      |
|            |      |      | irst |      |      |      |      |      |
|            |      |      | and  |      |      |      |      |      |
|            |      |      | last |      |      |      |      |      |
|            |      |      | axle |      |      |      |      |      |
|            |      |      | in   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | s    |      |      |      |      |      |
|            |      |      | pan. |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            |      |      | 3\.  |      |      |      |      |      |
|            |      |      | Mult |      |      |      |      |      |
|            |      |      | iply |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | CLC  |      |      |      |      |      |
|            |      |      | by   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | c    |      |      |      |      |      |
|            |      |      | orre |      |      |      |      |      |
|            |      |      | spon |      |      |      |      |      |
|            |      |      | ding |      |      |      |      |      |
|            |      |      | mu   |      |      |      |      |      |
|            |      |      | ltip |      |      |      |      |      |
|            |      |      | lier |      |      |      |      |      |
|            |      |      | in   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | tabl |      |      |      |      |      |
|            |      |      | e\*. |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            |      |      | 4\.  |      |      |      |      |      |
|            |      |      | The  |      |      |      |      |      |
|            |      |      | r    |      |      |      |      |      |
|            |      |      | esul |      |      |      |      |      |
|            |      |      | ting |      |      |      |      |      |
|            |      |      | nu   |      |      |      |      |      |
|            |      |      | mber |      |      |      |      |      |
|            |      |      | is   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | scal |      |      |      |      |      |
|            |      |      | e\'s |      |      |      |      |      |
|            |      |      | max  |      |      |      |      |      |
|            |      |      | imum |      |      |      |      |      |
|            |      |      | conc |      |      |      |      |      |
|            |      |      | entr |      |      |      |      |      |
|            |      |      | ated |      |      |      |      |      |
|            |      |      | load |      |      |      |      |      |
|            |      |      | for  |      |      |      |      |      |
|            |      |      | a    |      |      |      |      |      |
|            |      |      | si   |      |      |      |      |      |
|            |      |      | ngle |      |      |      |      |      |
|            |      |      | span |      |      |      |      |      |
|            |      |      | b    |      |      |      |      |      |
|            |      |      | ased |      |      |      |      |      |
|            |      |      | on   |      |      |      |      |      |
|            |      |      | the  |      |      |      |      |      |
|            |      |      | veh  |      |      |      |      |      |
|            |      |      | icle |      |      |      |      |      |
|            |      |      | co   |      |      |      |      |      |
|            |      |      | nfig |      |      |      |      |      |
|            |      |      | urat |      |      |      |      |      |
|            |      |      | ion. |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
|            |      |      | \    |      |      |      |      |      |
|            |      |      | *See |      |      |      |      |      |
|            |      |      | note |      |      |      |      |      |
|            |      |      | and  |      |      |      |      |      |
|            |      |      | for  |      |      |      |      |      |
|            |      |      | mula |      |      |      |      |      |
|            |      |      | on   |      |      |      |      |      |
|            |      |      | next |      |      |      |      |      |
|            |      |      | p    |      |      |      |      |      |
|            |      |      | age. |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 5**^1^**   | 1    |      |      |      |      |      |      |      |
|            | .000 |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 6**^1^**   | 1    |      |      |      |      |      |      |      |
|            | .000 |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 7**^1^**   | 1    |      |      |      |      |      |      |      |
|            | .000 |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 8 and      | 1    | 1    |      |      |      |      |      |      |
| l          | .000 | .000 |      |      |      |      |      |      |
| ess**^1^** |      |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| More than  | 1    | 1    |      |      |      |      |      |      |
| 8**^1^**   | .118 | .235 |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 9          | 1    | 1    |      |      |      |      |      |      |
|            | .147 | .257 |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 10         | 1    | 1    |      |      |      |      |      |      |
|            | .176 | .279 |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 11         | 1    | 1    |      |      |      |      |      |      |
|            | .206 | .301 |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 12         | 1    | 1    | 1    | 1    |      |      |      |      |
|            | .235 | .324 | .471 | .632 |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 13         | 1    | 1    | 1    | 1    |      |      |      |      |
|            | .265 | .346 | .490 | .651 |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 14         | 1    | 1    | 1    | 1    |      |      |      |      |
|            | .294 | .368 | .510 | .669 |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 15         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .324 | .390 | .529 | .688 | .853 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 16         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .353 | .412 | .549 | .706 | .871 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 17         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .382 | .434 | .569 | .724 | .888 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 18         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .412 | .456 | .588 | .743 | .906 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 19         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .441 | .478 | .608 | .761 | .924 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 20         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .471 | .500 | .627 | .779 | .941 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 21         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .500 | .522 | .647 | .798 | .959 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 22         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .529 | .544 | .667 | .816 | .976 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 23         | 1    | 1    | 1    | 1    | 1    |      |      |      |
|            | .559 | .566 | .686 | .835 | .994 |      |      |      |
+------------+------+------+------+------+------+------+------+------+
| 24         | 1    | 1    | 1    | 1    | 2    | 2    |      |      |
|            | .588 | .588 | .706 | .853 | .012 | .176 |      |      |
+------------+------+------+------+------+------+------+------+------+
| 25         | 1    | 1    | 1    | 1    | 2    | 2    |      |      |
|            | .618 | .610 | .725 | .871 | .029 | .194 |      |      |
+------------+------+------+------+------+------+------+------+------+
| 26         |      | 1    | 1    | 1    | 2    | 2    |      |      |
|            |      | .632 | .745 | .890 | .047 | .211 |      |      |
+------------+------+------+------+------+------+------+------+------+
| 27         |      | 1    | 1    | 1    | 2    | 2    |      |      |
|            |      | .654 | .765 | .908 | .065 | .228 |      |      |
+------------+------+------+------+------+------+------+------+------+
| 28         |      | 1    | 1    | 1    | 2    | 2    | 2    |      |
|            |      | .676 | .784 | .926 | .082 | .245 | .412 |      |
+------------+------+------+------+------+------+------+------+------+
| 29         |      | 1    | 1    | 1    | 2    | 2    | 2    |      |
|            |      | .699 | .804 | .945 | .100 | .262 | .429 |      |
+------------+------+------+------+------+------+------+------+------+
| 30         |      | 1    | 1    | 1    | 2    | 2    | 2    |      |
|            |      | .721 | .824 | .963 | .118 | .279 | .445 |      |
+------------+------+------+------+------+------+------+------+------+
| 31         |      | 1    | 1    | 1    | 2    | 2    | 2    |      |
|            |      | .743 | .843 | .982 | .135 | .297 | .462 |      |
+------------+------+------+------+------+------+------+------+------+
| 32         |      | 1    | 1    | 2    | 2    | 2    | 2    | 2    |
|            |      | .765 | .863 | .000 | .153 | .314 | .479 | .647 |
+------------+------+------+------+------+------+------+------+------+
| 33         |      |      | 1    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .882 | .018 | .171 | .331 | .496 | .664 |
+------------+------+------+------+------+------+------+------+------+
| 34         |      |      | 1    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .902 | .037 | .188 | .348 | .513 | .680 |
+------------+------+------+------+------+------+------+------+------+
| 35         |      |      | 1    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .922 | .055 | .206 | .365 | .529 | .697 |
+------------+------+------+------+------+------+------+------+------+
| 36         |      |      | 2.00 | 2    | 2    | 2    | 2    | 2    |
|            |      |      | 0^2^ | .074 | .224 | .382 | .546 | .713 |
+------------+------+------+------+------+------+------+------+------+
| 37         |      |      | 2.00 | 2    | 2    | 2    | 2    | 2    |
|            |      |      | 0^2^ | .092 | .241 | .400 | .563 | .730 |
+------------+------+------+------+------+------+------+------+------+
| 38         |      |      | 2.00 | 2    | 2    | 2    | 2    | 2    |
|            |      |      | 0^2^ | .110 | .259 | .417 | .580 | .746 |
+------------+------+------+------+------+------+------+------+------+
| 39         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .000 | .129 | .276 | .434 | .597 | .763 |
+------------+------+------+------+------+------+------+------+------+
| 40         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .020 | .147 | .294 | .451 | .613 | .779 |
+------------+------+------+------+------+------+------+------+------+
| 41         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .039 | .165 | .312 | .468 | .630 | .796 |
+------------+------+------+------+------+------+------+------+------+
| 42         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .059 | .184 | .329 | .485 | .647 | .813 |
+------------+------+------+------+------+------+------+------+------+
| 43         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .078 | .202 | .347 | .502 | .664 | .829 |
+------------+------+------+------+------+------+------+------+------+
| 44         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .098 | .221 | .365 | .520 | .681 | .846 |
+------------+------+------+------+------+------+------+------+------+
| 45         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .118 | .239 | .382 | .537 | .697 | .862 |
+------------+------+------+------+------+------+------+------+------+
| 46         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .137 | .257 | .400 | .554 | .714 | .879 |
+------------+------+------+------+------+------+------+------+------+
| 47         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .157 | .276 | .418 | .571 | .731 | .895 |
+------------+------+------+------+------+------+------+------+------+
| 48         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .176 | .294 | .435 | .588 | .748 | .912 |
+------------+------+------+------+------+------+------+------+------+
| 49         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .196 | .313 | .453 | .605 | .765 | .928 |
+------------+------+------+------+------+------+------+------+------+
| 50         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .216 | .331 | .471 | .623 | .782 | .945 |
+------------+------+------+------+------+------+------+------+------+
| 51         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .235 | .349 | .488 | .640 | .798 | .961 |
+------------+------+------+------+------+------+------+------+------+
| 52         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .255 | .368 | .506 | .657 | .815 | .978 |
+------------+------+------+------+------+------+------+------+------+
| 53         |      |      | 2    | 2    | 2    | 2    | 2    | 2    |
|            |      |      | .275 | .386 | .524 | .674 | .832 | .994 |
+------------+------+------+------+------+------+------+------+------+
| 54         |      |      | 2    | 2    | 2    | 2    | 2    | 3    |
|            |      |      | .294 | .404 | .541 | .691 | .849 | .011 |
+------------+------+------+------+------+------+------+------+------+
| 55         |      |      | 2    | 2    | 2    | 2    | 2    | 3    |
|            |      |      | .314 | .423 | .559 | .708 | .866 | .028 |
+------------+------+------+------+------+------+------+------+------+
| 56         |      |      | 2    | 2    | 2    | 2    | 2    | 3    |
|            |      |      | .333 | .441 | .576 | .725 | .882 | .044 |
+------------+------+------+------+------+------+------+------+------+
| 57         |      |      | 2.35 | 2    | 2    | 2    | 2    | 3    |
|            |      |      | 3^3^ | .460 | .594 | .742 | .899 | .061 |
+------------+------+------+------+------+------+------+------+------+
| 58         |      |      |      | 2    | 2    | 2    | 2    | 3    |
|            |      |      |      | .478 | .612 | .760 | .916 | .077 |
+------------+------+------+------+------+------+------+------+------+
| 59         |      |      |      | 2    | 2    | 2    | 2    | 3    |
|            |      |      |      | .496 | .629 | .777 | .933 | .094 |
+------------+------+------+------+------+------+------+------+------+
| 60         |      |      |      | 2    | 2    | 2    | 2    | 3    |
|            |      |      |      | .515 | .647 | .794 | .950 | .110 |
+------------+------+------+------+------+------+------+------+------+
| \*Note:    |      |      |      |      |      |      |      |      |
| This table |      |      |      |      |      |      |      |      |
| was        |      |      |      |      |      |      |      |      |
| developed  |      |      |      |      |      |      |      |      |
| based upon |      |      |      |      |      |      |      |      |
| the        |      |      |      |      |      |      |      |      |
| following  |      |      |      |      |      |      |      |      |
| formula.   |      |      |      |      |      |      |      |      |
| Values may |      |      |      |      |      |      |      |      |
| be rounded |      |      |      |      |      |      |      |      |
| in some    |      |      |      |      |      |      |      |      |
| cases for  |      |      |      |      |      |      |      |      |
| ease of    |      |      |      |      |      |      |      |      |
| use.       |      |      |      |      |      |      |      |      |
| $          |      |      |      |      |      |      |      |      |
| W = r \tim |      |      |      |      |      |      |      |      |
| es \text{5 |      |      |      |      |      |      |      |      |
| 00}\left\l |      |      |      |      |      |      |      |      |
| brack \lef |      |      |      |      |      |      |      |      |
| t( \frac{\ |      |      |      |      |      |      |      |      |
| text{LN}}{ |      |      |      |      |      |      |      |      |
| N - 1} \ri |      |      |      |      |      |      |      |      |
| ght)\text{ |      |      |      |      |      |      |      |      |
|   } + \tex |      |      |      |      |      |      |      |      |
| t{  }\text |      |      |      |      |      |      |      |      |
| {12}N\text |      |      |      |      |      |      |      |      |
| {  } + \te |      |      |      |      |      |      |      |      |
| xt{  }\tex |      |      |      |      |      |      |      |      |
| t{36} \rig |      |      |      |      |      |      |      |      |
| ht\rbrack$ |      |      |      |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
| ^1^ Tandem |      |      |      |      |      |      |      |      |
| Axle       |      |      |      |      |      |      |      |      |
| Weight.    |      |      |      |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
| ^2^        |      |      |      |      |      |      |      |      |
| E          |      |      |      |      |      |      |      |      |
| xception - |      |      |      |      |      |      |      |      |
| These      |      |      |      |      |      |      |      |      |
| values in  |      |      |      |      |      |      |      |      |
| the third  |      |      |      |      |      |      |      |      |
| column     |      |      |      |      |      |      |      |      |
| correspond |      |      |      |      |      |      |      |      |
| to the     |      |      |      |      |      |      |      |      |
| maximum    |      |      |      |      |      |      |      |      |
| loads in   |      |      |      |      |      |      |      |      |
| which the  |      |      |      |      |      |      |      |      |
| inner      |      |      |      |      |      |      |      |      |
| bridge     |      |      |      |      |      |      |      |      |
| dimensions |      |      |      |      |      |      |      |      |
| of 36, 37, |      |      |      |      |      |      |      |      |
| and 38     |      |      |      |      |      |      |      |      |
| feet are   |      |      |      |      |      |      |      |      |
| considered |      |      |      |      |      |      |      |      |
| to be      |      |      |      |      |      |      |      |      |
| equivalent |      |      |      |      |      |      |      |      |
| to 39      |      |      |      |      |      |      |      |      |
| feet. This |      |      |      |      |      |      |      |      |
| allows a   |      |      |      |      |      |      |      |      |
| weight of  |      |      |      |      |      |      |      |      |
| 68 000 lb  |      |      |      |      |      |      |      |      |
| on axles 2 |      |      |      |      |      |      |      |      |
| through 5. |      |      |      |      |      |      |      |      |
|            |      |      |      |      |      |      |      |      |
| ^3^        |      |      |      |      |      |      |      |      |
| C          |      |      |      |      |      |      |      |      |
| orresponds |      |      |      |      |      |      |      |      |
| to the     |      |      |      |      |      |      |      |      |
| Interstate |      |      |      |      |      |      |      |      |
| Gross      |      |      |      |      |      |      |      |      |
| Weight     |      |      |      |      |      |      |      |      |
| Limit.     |      |      |      |      |      |      |      |      |
+------------+------+------+------+------+------+------+------+------+

**Scales Code Index**

Acceptance 10, 23, 25, 26, 27, 28

Acceptance tolerance 10, 25, 26, 27, 28

Accuracy 10, 11, 12, 13, 15, 16, 23, 26, 31

Accuracy class 10, 12, 13, 15, 16, 23, 26, 31

Adjustable components 8, 12

Adjustment 8, 9, 12, 22, 35

Approaches 32, 33

Audit trail 8

Automatic indicating scales 18, 20, 24

Automatic zero-setting mechanism 9, 13

Axle-load scales 3, 10, 11, 18, 24, 31, 33

Balance condition 3, 9, 10, 26, 30, 35

Balance indicator 3, 10, 11, 25, 28, 29

Balance indicators 25, 28

Balance position 5

Barometric pressure 26, 30

Capacity 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 23, 24,
25, 26, 28, 29, 30, 31, 33, 34, 35

Capacity indication 6

Center-of-zero 3

*Certificate of Conformance* 13

Class 4, 8, 9, 10, 11, 12, 13, 15, 16, 18, 20, 24, 26, 27, 29, 30, 31,
32, 33

CLC 14, 15, 16, 18, 36

Clearance 5, 10, 32

Computing scale 6, 7

Concentrated Load Capacity 15

Consecutive-car test 21, 22, 23

Coupled-in-motion 27, 35

Coupled-in-motion railroad weighing systems 27

Crane and hopper (other than grain hopper) 13

Crane scales 20, 31

Dairy-product-test 10, 11, 18, 23

Damping means 11

Decreasing load test 24, 26

Direct sales 5, 7, 9, 10, 12

Discrimination test 20

Distributed-car test 22

Electric power supply 30

Environmental factors 20, 32

Foundation 32

Graduations 4, 5, 6, 7, 10

Grain test scales 31

Grain-test 10, 32

Hanging scale 20, 32

Hanging scales 20

Hoists 33

Hopper scales 20, 26, 31

I 4, 8, 9, 10, 11, 12, 13, 16, 18, 23, 24, 26, 27, 28, 29, 30, 31, 32,
33

II 4, 9, 10, 11, 12, 13, 16, 18, 23, 24, 26, 27, 28, 29, 30, 31, 33

III 4, 9, 10, 12, 13, 16, 18, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33

III L 9, 12, 13, 16, 23, 24, 26, 27, 28, 29, 30, 31, 32, 33

IIII 4, 12, 13, 16, 18, 23, 26, 27, 28, 29, 31, 33

Index of an indicator 4, 5

Indicating element 3, 11, 14, 15, 16, 27, 28, 32

Indicator 3, 4, 5, 6, 8, 10, 11, 13, 16, 25, 26, 28, 29, 35

Influence factors 26, 29

Initial verification 21, 22

Initial zero-setting mechanism 6, 10

Installation requirements 32

Level 9, 10, 11, 19, 33, 34, 35

Level condition 11, 34, 35

Level-indicating means 10

Livestock scales 9, 14, 16, 32

Load cell 12, 14, 15, 16, 32

Load cell verification interval 12, 16

Main elements 14, 27

Maintenance 23, 24, 25, 26, 27, 28, 32, 35

Maintenance requirements 35

Maintenance tolerance 23, 24, 26, 27, 28

Manual gross weight entries 9, 35

**Marking requirements** 14, 15

Material test 20, 24

Minimum load 33, 34, 35

Minimum test weights 20, 21

Money-value computation 7

Money-value graduations 6, 7

Monorail scale 4, 10, 19, 24

Multi-interval 12, 13, 16, 26

Multiple Range 12, 26

No-load reference value 3

Nominal capacity 5, 14, 15, 16, 18, 19, 23, 25, 34

Operating temperature 26, 30

Parallax 5

Parcel post scales 23, 24, 25

Poise 5, 6

Portable axle-load weighers 3, 20, 26, 31, 34

Postal 4, 6, 16, 23, 24, 25, 31, 35

Power interruption 30

Prepackaging scale 8, 34

Prescription 10, 11, 13, 23, 24

Railway track scales 9, 11, 14, 16, 19, 20, 25, 31, 32

Ratio test 20, 26

Readability 5

Recorded representations 3, 7

Recording elements 3, 11, 28

Repeatability 28

RFI 20, 25, 30, 32

Scale modification 35

Sealing 8

Security seal 8

Sensitivity requirement 23, 25

Sensitivity test 20

Shift test 18, 19, 20, 28

Stock racks 33

Strain-load test 20

Subsequent verification 22, 26

Supports 18, 32

Symmetry 4

Tare 9, 10, 26

*Temperature* 13, 15, 16, 26, 29, 30

Test loads 18, 19, 20, 21, 24, 25, 26, 27, 28

Time dependence 28

Tolerances 10, 11, 19, 20, 21, 23, 24, 26, 28, 30, 34

Travel 5, 11, 23

*Type evaluation* 13, 14, 26, 27

Uncoupled-in-motion 23

Uncoupled-in-motion railroad weighing system 23

Unit weights 6, 16, 28

Use requirements 33

Vehicle on-board weighing system 9, 11, 19, 31

Vehicle scale 9, 14, 18, 30, 32, 33, 34, 35

Vehicle scales 9, 18, 30, 32, 33, 34

Verification scale interval 4, 12

Weighing elements 12, 18, 19, 32

Weight ranges 6, 16

Weight units 4

Wheel-load weighers 3, 10, 11, 20, 26, 31, 34

Zero indication 3, 30

Zero-load adjustment 9, 35

Zero-load balance 8, 9, 10, 20, 30, 35

[^1]: Weight values shall be identified by kilogram, kg, grams, g,
    ounces, oz, pound, lb, or the sign \"#.\" For devices interfaced
    with scales indicating in metric units, the unit price may be
    expressed in price per 100 grams.

    (Amended 1995)

[^2]: See Footnote 1 to Table 3 Parameters for Accuracy Classes

[^3]: 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)

[^4]: 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)

[^5]: 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 quantity 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 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.