NIST OWM Analysis

2024 NCWM Interim S&T Agenda Items 

December 20, 2023

1

NIST Office of Weights and Measures (OWM) Analysis

Specifications and Tolerances (S&T)

2024 NCWM Interim Meeting Agenda

The NIST OWM Analysis is submitted to assist the Weights and Measures community as it deliberates on 

items before the Conference. NIST OWM offers these comments and recommendations based on

information and input available as of the date of this report. This does not address information received 

after this date.

Language shown in a boldface print by striking out information to be deleted and underlining

information to be added. Requirements that are proposed to be nonretroactive are printed in boldface

italics. 

Assessment of items contained within this report is as the date of this report and does not address 

information received after this date.

For additional information or assistance please contact a NIST OWM Technical Advisor: 

Jan Konijnenburg, S&T Committee, jan.konijnenburg@nist.gov or (301) 975-4004

Diane Lee, S&T Committee, diane.lee@nist.gov or (301) 975-4405

Loren Minnich, S&T Committee, loren.minnich@nist.gov (202) 430-0435

Juana Williams, S&T Committee, juana.williams@nist.gov or (301) 975-3989

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Subject Series List for the Specifications and Tolerances Committee

Handbook 44 – General Code......................................................................................................GEN Series

Scales......................................................................................................................................SCL Series

Belt-Conveyor Scale Systems................................................................................................BCS Series

Automatic Bulk Weighing Systems.....................................................................................ABW Series

Weights..................................................................................................................................WTS Series

Automatic Weighing Systems.............................................................................................. AWS Series

Weigh-In-Motion Systems used for Vehicle Enforcement Screening ..................................WIM Series

Liquid-Measuring Devices................................................................................................... LMD Series

Vehicle-Tank Meters............................................................................................................ VTM Series

Liquefied Petroleum Gas and Anhydrous Ammonia Liquid-Measuring Devices..................LPG Series

Hydrocarbon Gas Vapor-Measuring Devices........................................................................HGV Series

Cryogenic Liquid-Measuring Devices ..................................................................................CLM Series

Milk Meters.......................................................................................................................... MLK Series

Water Meters........................................................................................................................ WTR Series

Mass Flow Meters................................................................................................................MFM Series

Carbon Dioxide Liquid-Measuring Devices.......................................................................... CDL Series

Hydrogen Gas-Metering Devices.........................................................................................HGM Series

Electric Vehicle Refueling Systems.......................................................................................EVF Series

Vehicle Tanks Used as Measures..........................................................................................VTU Series

Liquid Measures................................................................................................................... LQM Series

Farm Milk Tanks...................................................................................................................FMT Series

Measure-Containers.............................................................................................................. MRC Series

Graduates...............................................................................................................................GDT Series

Dry Measures ........................................................................................................................DRY Series

Berry Baskets and Boxes....................................................................................................... BBB Series

Fabric-Measuring Devices..................................................................................................... FAB Series

Wire-and Cordage-Measuring Devices................................................................................WAC Series

Linear Measures......................................................................................................................LIN Series

Odometers .............................................................................................................................ODO Series

Taximeters...............................................................................................................................TXI Series

Timing Devices ......................................................................................................................TIM Series

Grain Moisture Meters (a)....................................................................................................GMA Series

Grain Moisture Meters (b)....................................................................................................GMB Series

Near-Infrared Grain Analyzers............................................................................................... NIR Series

Multiple Dimension Measuring Devices............................................................................. MDM Series

Electronic Livestock, Meat, and Poultry Evaluation Systems and/or Devices.......................LVS Series

Transportation Network Measuring Systems.........................................................................TNS Series

Other Items...................................................................................................................................OTH Series
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Table of Contents

SCL – Scales ............................................................................................................................ 5

AWS – Automatic Weighing Systems Code......................................................................... 68

WIM – Weigh-in-Motion Systems – Tentative Code............................................................. 78

LMD – Liquid Measuring Devices ....................................................................................... 100

VTM – Vehicle Tank Meters ................................................................................................. 103
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LPG – Liquified Petroleum Gas and Anhydrous Ammonia Liquid-Measuring Devices .. 116

MLK – MILK METERS........................................................................................................... 135

HGM – Hydrogen Gas-Measuring Devices ......................................................................... 139

EVF – Electric Vehicle Fueling Systems............................................................................. 144
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GMA – Grain Moisture Meters 5.56 (a)................................................................................ 210

OTH – Other Items ............................................................................................................... 216

Item Block 1 (B1) Transfer Standard................................................................................ 255

References: .......................................................................................................................... 258

Appendix A. Supplemental Documents: ........................................................................... 259

Appendix B. List of Symbols, Abbreviations and Acronyms........................................... 259
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Details of All Items

(In order by Reference Key)

SCL – Scales

SCL-24.1 S.1.7. Capacity Indication, Weight Ranges, and Unit Weights.

Source: Rice Lake Weighing System

Submitter’s Purpose and Justification:

The term “Electronic computing scales” is not defined and makes S.1.7.(b). a confusing statement. The 

term should be struck and replaced with retail scale, ECR or POS if that is the intent.

All digital scales made today are electronic computing scales. They compute weight values for analog 

signal to digital signal. This is a confusing statement and should be amended for clarification.

The submitter requested Voting status for 2024.

NIST OWM Executive Summary for SCL-24.1 – S.1.7. Capacity Indication, Weight Ranges, and 

Unit Weights

NIST OWM Recommendation: Withdrawn

• It is unclear what problem the submitter is trying to solve. It appears that the submitter 

misinterpreted the term “computing scale”. A computing scale is defined as: “One that 

indicates the money values of amounts of commodity weighed, at predetermined unit prices, 

throughout all or part of the weighing range of the scale.”

• The term “electronic” was included to differentiate between analog computing scales, e.g., 

drum or fan type scales, from scales that display weight values in an electronic digital format.

• OWM believes the proposed change is ambiguous and would cause more confusion than the 

terms used in the current language.

Table 2. Summary of Recommendations

SCL-24.1 – S.1.7. Capacity Indication, Weight Ranges, and Unit Weights

Status Recommendation Note* Comments

Submitter Voting

OWM Withdrawn

WWMA Developing

NEWMA Withdrawn

SWMA Withdrawn 

CWMA Developing
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NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend NIST Handbook 44, Scales Code as follows:

S.1.7. Capacity Indication, Weight Ranges, and Unit Weights.

(a) Gross Capacity. – An indicating or recording element shall not display nor record any values 

when the gross load (not counting the initial dead load that has been canceled by an initial 

zero-setting mechanism) is in excess of 105 % of scale capacity.

(b) Capacity Indication. – Electronic computing scalesRetail scales, POS, and ECR

(excluding postal scales and weight classifiers) shall neither display nor record a gross or 

net weight in excess of scale capacity plus 9 d.

[Nonretroactive as of January 1, 1993]

(Amended 20XX)

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.

(Amended 1990, 1992, 1995, and 20XX)

NIST OWM Detailed Technical Analysis: 

It is unclear what problem the submitter tries to solve. The term “computing scale” is defined. The term 

“electronic” is a general adjective that is widely understood and does not need further explanation.

The proposed change is ambiguous and will probably cause more confusion than the current language:
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• The terms POS and ECR are insufficient. POS stands for point of sale indicating the location of 

the transaction, not the instrument. ECR stands for electronic cash register which does not 

include the weighing instrument connected to the ECR.

• The term “retail scale” is undefined but the term “retail device” is. A retail device is used for sale 

to the end user. The definition does not require the device to have a price calculation function as 

the definition of “computing scale” describes. 

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, Greg VanderPlaats from Minnesota stated that the terms ‘Retail 

Scale’, ECR, and POS are not defined in NIST Handbook 44. Steve Peter (Wisconsin) agreed with 

Greg’s comments. Steve also suggested adding the word ‘Price’ to the term Electronic Computing Scales.

The Committee recommends that this item is a Developing item.

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, the SMA has not had the opportunity to assess the item and will 

meet in November 2023. Steve Harrington (Oregon) expressed confusion regarding terms in the 

proposed language. Steve recommended Developing as a status of this item. The State and two counties 

in California echoed the confusion expressed by Oregon. Kurt Floren (Los Angeles County, California) 

stated there is an existing definition for computing scales and this item may confuse these existing 

definitions. POS means Point of Sale not Point of Sale System and ECR means Electronic Cash Register 

which may not be interfaced with a weighing device. Kurt would like more information from Rice Lake 

and/or SMA regarding this item and agreed with Oregon on a Developmental status for this item. During 

open hearings testimony was received that the SMA has not evaluated this proposal. Comments were 

heard supporting a Developmental status, as the item needs further clarification on the terms and 

definitions in the item. The WWMA S&T Committee recommends that this item be assigned a 

Developing status. This will allow the submitter the opportunity to address the comments heard during 

the open hearings. The Committee also looks forward to comments from the SMA and NIST OWM 

regarding this item.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, the Committee heard no comments on this item during Open 

Hearings. The Committee does not agree that the term electronic computing scales is confusing, 

therefore, making this item unnecessary.

The Committee recommends Withdrawal of this item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, the State of New York opposed this item as computing scales are 

clearly defined in the definitions and not all electronic retail scales are computing scales. The 
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Commonwealth of Massachusetts recommends withdrawing this item. Upon consensus of the body, the 

Committee recommended this item be Withdrawn.

SCL-24.2. Multiple Sections Regarding Tare

Source: Ross Andersen (retired New York)

Submitter’s Purpose and Justification:

Reduce confusion regarding net weight and tare issues by defining terms and adds specific requirements 

for tare operations and for marking and printing of net, gross and tare weight values.

This proposal recommends changes to the Scales Code to address: 

(1) issues of poor terminology that lead to confusion in discussion of net weight (and tare) issues, and 

(2) absence of specifics in the regulation of net weight that leads to ambiguity in enforcement. 

Both of these issues emerged from discussions of the e vs d issues by the Verification Scale Division e 

Task Group. The Task Group however, decided both were outside the scope of its charge. 

Issue 1. – The terminology relating to net weight and tare in the HB44 Scales Code is confusing since the 

three main terms (net, gross, and tare) may each be used to mean three different things. For example, the 

term “net” can refer to 1) the weight value on which a commercial transaction is based, 2) the mode of 

indication of an instrument, or 3) the load placed on the load receptor. 

A good example is the use of the common expression “net equals gross minus tare.” primarily this is a 

formula describing the loading of the instrument in the weighing procedure. 

Net load = Gross load - Tare load

Commodity = Commodity + Tare - Tare

What about the instrument indication? In the terminology of the instrument, a gross indication is the 

instrument indication when the weighing begins at a no-load zero indication. In the case of a scale with no 

tare mechanism we find:

Net weight = Gross indication - Gross indication

Net load = Gross Load - Tare load

Commodity = Commodity + Tare - Tare

With a tare mechanism or a keyboard tare mechanism, the instrument scale is set to net zero 

corresponding to the tare load. The Net indication is zero. We find:

Net weight = Net indication - (Tare indication is zero)

Net load = Gross load

Commodity = Commodity + Tare

The objective of any weighing process is to find the net weight, which might be assigned from one or 

more instrument indications with different loads on the load receptor and different methods of operating 
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the instrument. We work with these terms every day, but we ignore or struggle with the inherent 

confusion. Good regulations avoid this kind of confusion using clear terminology.

Issue 2. – There are only a few specifications governing tare operations in the Scales Code. I am not 

including user requirements that don’t apply to the instrument. A word search of the terms “tare” and 

“net weight” point us to only six Specifications, one Note, and one Tolerance as in the table below. 

Section Subject # Requirements

S.1.2.1. Weight Units 2

S.1.7. Manual Weight Entries 1

S.1.8. Recording Net Weight POS Scales 2

S.1.12. Manual Weight 1

S.2.1.6. Combined Zero/Tare 1

S.2.3. Tare 2

S.2.3.1. Tare Digital Monorail Scales 2

N.1.12. Strain Load Tests N/A

T.N.2.1. Tolerance Application to Net Weight N/A

The number of requirements is an assessment of the number of requirements requiring a distinct test to 

verify compliance. In total, there are 11 tests required to verify the literal requirements in the Code. Yet 

the NTEP checklist for an electronic scale has pages of tests governing tare operations. I concede that 

many of those can also be derived from General Code requirements, but general also comes with a lack of 

specificity. This is no suggestion that Pub 14 is wrong in any way. There has always been this challenge 

to ensure NTEP is following HB44, and not the other way around. There is another challenge to not overregulate. It is generally better to have fewer, but clearer, requirements. 

If you believe the current Code is sufficiently unambiguous, try to answer the following questions using 

only the text in HB44? No peeking in Pub 14.

What is meant in T.N.2.1. by “the net weight indication of any possible tare load using certified test 

weights.” If you ask different people, you might get many different answers. 

Can you point to any guidance in the Notes section to help answer question 1 or conduct the test in order 

to apply the tolerances?

Must keyboard tare, pre-programmed tare, and pushbutton tare all result in the same net weight? 

If you say yes, on what code requirement do you base your decision? Different weighing procedures can 

produce different results by one scale division.

If the instrument simultaneously indicates the Net, Gross, and Tare weights (or prints them), do the values 

have to be in mathematical agreement? 

If you say yes, on what code requirement do you base your decision? Under some circumstances 

mathematical agreement cannot be mandated due to rounding issues.
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If an instrument has a dedicated tare weight display, do tolerances apply to that indication?

If an instrument records multiple values, e.g., net weight, gross weight, and tare weight, how must the 

values be identified either on the display or the printed record?

These are just a few questions to highlight a lack of clarity in the current Code. The proposal is intended 

to help resolve these issues.

Regarding the Proposed Definitions:

Justification: The current definition of tare mechanism does not differentiate between tare 

alternatives, like pushbutton tare, or keyboard and programmed tare. The amended definition of tare 

mechanism and the new definition of preset tare mechanism ensure clarity, particularly as they 

operate differently, and the tolerances should be applied when a tare mechanism is in operation but 

not when a preset tare mechanism is in operation. (See Revision to T.N.2.1.) 

The new definitions relating to net, gross, and tare help clarify that these terms have multiple 

meanings. By using “loads” for the loading of the instrument, “indications” for the instrument 

indications, and “weights” for the transaction record, we can keep the meanings specific to the intent. 

Some key points:

• Weights may be assigned by the operator or by the instrument. Examples: 1) A gross indication 

when the commodity is the only load on the load receptor is designated the net weight by the 

operator. 2) A weigh-in/weigh-out system employs two gross indications that are used to 

calculate a net weight. If the operator calculates the net weight, the operator is also responsible to 

identify the respective net, gross and tare weights. If the instrument calculates the net weight, it 

must identify the respective net, gross, and tare weights. 

• Requirements applicable to indications are also applicable to recorded representations (values 

printed or transmitted by the instrument) as per G-S.5.6. Note that some code requirements 

emphasize the recorded representations (redundantly), and some do not. This does not apply to 

actions of an operator such as manually computing net values from two measured weight values 

for gross and tare.

• The term “gross load” unavoidably has two meanings, but this is acceptable since the operator (or 

the official) clearly knows which applies based on how the scale is used. 

Example 1: a candy store may have a scoop that is sometimes used in the weighing operation. For 

the purposes of S.1.7. Capacity Indications, the scoop is part of the gross load placed on the load 

receptor and the weighing range of the scale is reduced by the scoop weight. However, for the 

purposes of the transaction, the scoop becomes part of the load receptor after a zero operation and 

is not part of the gross load (commodity and tare). A possible exception is the scale with a 

combined zero/tare key. However, these are not permitted in direct sale and the net weighing 

essentially begins at gross zero that is accurate to at least 1⁄4 e. 

Example 2: if the commodity alone is placed on the load receptor, it is a gross load (by the first 

meaning) and a net load. This is the case when candy in the scoop is weighed for the transaction 

after including the scoop in the gross zero as in example 1. The net load is introduced into the 

packaging (tare) after the weighing operation.

Example 3: if the tare alone is placed on the load receptor it is thus a gross load (by the first 

meaning) and a tare load. However, there are nuances to the meaning of tare load (next bullet).
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• The term “tare load” is used only once in the current Scales Code in T.N.2.1. The proposed 

revision to that section would remove it. In practice, a tare load results in either a non-zero gross 

indication, or a zero net indication. Both are consistent with the new definitions of gross and net 

loads. There is also the possibility that a tare weighing mechanism is in use that displays or prints 

the tare weight. However, the value displayed on the tare weighing mechanism does not 

necessarily correspond to the current loading, since the tare weighing mechanism will remain at 

the tare indication when either the tare is removed from or the gross load (commodity and tare) 

are placed on the load receptor.

• The term “tare indication” is necessary as tolerances are applicable to a dedicated tare display in 

the revised T.N.2.1.

• To further help explain the terminology, consider four basic weighing procedures. Instrument in 

all examples is Class III Max 30 lb d = 0.01 lb

(Net, gross and tare descriptors in parentheses are optional as per proposed S.1.15.)

1. Direct Weighing

Procedure 

Step

Loading Internal 

Value

Indication Weight

(Transaction)

1 zero No 0.000 lb (Gross) 0.00 lb

2 weigh Net 4.283 lb (Gross) 4.28 lb (Net) 4.28 lb

2. Difference Weighing

Procedure 

Step

Loading Internal 

Value

Indication Weight

(Transaction)

1 zero No 0.000 lb (Gross) 0.00 lb

2 weigh* Tare 0.034 lb (Gross) 0.03 lb Tare 0.03 lb

3 zero No 0.000 lb (Gross) 0.00 lb

4 weigh* Gross 4.317 lb (Gross) 4.32 lb (Gross) 4.32 lb

5 calculate N/A N/A N/A Net 4.29 lb

* Steps 2 and 4 may be reversed, weighing gross in step 2 and tare in step 4.

3. Weighing using Tare Mechanism

Procedure 

Step

Loading Internal 

Value

Indication Weight

(Transaction)

1 zero No 0.000 lb (Gross) 0.00 lb

2 weigh Tare 0.034 lb (Gross) 0.03 lb

3 tare key Tare 0.000 lb Net 0.00 lb

4 weigh Gross 4.283 lb Net 4.28 lb (Net) 4.28 lb
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4. Weighing using Preset Tare Mechanism – Option (a)

Procedure 

Step

Loading Internal 

Value

Indication Weight

(Transaction)

1 zero No 0.000 lb (Gross) 0.00 lb

2 enter tare No 0.03 lb

3 tare key No 0.000 lb Net −0.03 lb

4 weigh Gross 4.317 lb Net 4.29 lb (Net) 4.29 lb

4. Weighing using Preset Tare Mechanism – Option (b)

Procedure 

Step

Loading Internal 

Value

Indication Weight

(Transaction)

1 zero No 0.000 lb (Gross) 0.00 lb

2 weigh Gross 4.317 lb (Gross) 4.32 lb

3 enter 

PLU

Gross 4.32 – 0.03 Net 4.29 lb (Net) 4.29 lb

In the above examples, you can read any row with a transaction weight to describe the weighing process 

for most cases. The exception is procedure 2 step 5 which is a calculation. 

Procedure 1 step 2 reads: net weight = gross indication of the net load. 

Procedure 2 step 2 reads: tare weight = gross indication of the tare load. 

Procedure 2 step 4 reads: gross weight = gross indication of the gross load.

Procedure 3 step 4 reads: net weight = net indication of the gross load.

Regarding S.1.1.1. Digital Indicating Elements.

Justification: The changes mirror those proposed by the Verification Scale Division e Task Group. The 

current Code has no requirement on the accuracy of zero setting. The new part (b) ensures that zero 

setting is accurate within 1/4 e. The amendments to (c) are further explained in the reports of the Task 

Group and are not relevant to this proposal. The proposed (b) is nonretroactive since it is a major change.

Regarding S.1.2.1. Digital Indicating Scales, Units.

Justification: In the current text it may be unclear that the second paragraph and the examples address 

multi-interval and multiple range scales weighing by difference, i.e., using two measured gross 

indications with no tare or preset tare in operation. The changes make this clear. Using the terminology 

of weights, indications and loads, the 1, 2 or 5 requirement for the scale division applies to 1) the gross 

indications for the gross and tare loads, and 2) the gross and tare weights recorded for the transaction.

The 1, 2, or 5 requirement does not apply to the calculated net weight, which may be displayed and/or 

printed. More on the mathematical agreement issue can be found in proposed S.1.17. below. As this is 

only a clarification, it does not alter the nonretroactive status of the section.
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This section does not apply to tare operations using tare or preset tare mechanisms. If either a tare 

mechanism or a preset tare mechanism is in operation, then the net weights in the examples would 

necessarily be displayed and printed as 50 kg (d = 5 kg) and 10.00 lb (d = 0.05 lb) respectively. Both 

would be rounded by the device to the d of the upper weighing range before being displayed. It seems 

highly unlikely that any multi-interval scale would print all three values, if equipped with a tare or preset 

tare mechanism.

Regarding S.1.7. Capacity Indication, Weights Ranges, and Unit Weights.

Justification: Notice in (a) the current requirement refers to values, but in (b) it refers to weights. This is 

an instance of multiple meanings colliding in the current Code. The changes are a clean-up since the 

section uses the terms net, gross and tare. The intent of this section is that no gross or net “indications” 

are displayed or printed when the “gross load” (meaning all materials exclusive of dead load) exceeds 

some limit above scale capacity. The current wording in (b) is incorrect since it appears that the net 

values could also reach capacity plus 9 d even with maximum tare. This doubles the scale capacity and is 

clearly not the intent of the section. NTEP has always applied this to mean no gross or net indications are 

permitted when the gross load (all materials other than dead load) exceeds capacity plus 9 d. As this is 

only a clarification of the original intent, it does not alter the nonretroactive status of the section.

Regarding S.2.3. Tare Mechanism and Preset Tare Mechanism, General.

Justification: The changes to S.2.3. are a cleanup of language consistent with the terms tare mechanism 

and preset tare mechanism. This backward application of tare has consistently been applied to both tare 

and preset tare in the past. As this is only a clarification, it does not alter the retroactive status of the 

affected section. 

The new specifications, S.2.3.1. and S.2.3.2., clarify the difference between the two kinds of tare 

mechanisms. Because these changes may be significant, they are proposed to be nonretroactive. With a 

tare mechanism, the net zero setting is required to be accurate to 1⁄4 e, parallel to the setting of gross zero 

in S.1.1.1.(b). With a preset tare mechanism, the net zero value is rounded off to the scale division d.

This means net weights are simple calculations of rounded gross weight minus rounded tare weight. For 

more explanation see justification for changes to T.N.2.1. below.

For a multi-interval scale this means having full access to the entire lower weighing range in net mode. 

Consider a 0 - 15 lb x 0.005 lb and 15-30 lb x 0.01 lb multi-interval scale. If the tare is 14 lb, the lower 

weighing range for net weights will coincide with gross loads between 14 lb to 29 lb. The upper range for 

net weights will coincide with gross loads between 29 lb to 30 lb. Notice also that a maximum preset tare 

on a multi-interval scale is limited to the Max of the lower weighing range.

Regarding S,1,15, Marking of Weight Indications and S.1.16. Printing of Weighing Results.

Justification: These new sections provide clear specifications for net weight and the use of tare 

mechanisms. Because these changes may be significant, they are proposed as nonretroactive. Without 

these sections, the decisions regarding appropriate markings are arbitrary. Note that NTEP relies heavily 

on G-S.6. (marking of controls and indications), but Pub 14 has no legal standing. What is clear to one 

person may not be clear to another when viewing the Scales Code. In S.1.15. the specifications governing 

marking of the weight displays are added. In S.1.16. the specifications governing printed records are 

added. This section comes largely from R76 section 4.6.11.
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Regarding S.1.17. Mathematical Agreement of Net, Gross and Tare Values.

Justification: Neither the Scales Code nor the General Code clearly addresses mathematical agreement of 

net, gross, and tare. Mathematical agreement is not an issue for most scales since they only display one or 

two of the net, gross and tare values. Instruments that display all three values are rare and will now be 

formally addressed in the Code to prevent confusion. The proposed sections make it clear that values 

calculated from two measured values must be in mathematical agreement. This is partially explained in 

the current S.1.2.1. With a preset tare mechanism, only the gross and tare weights are measured, while the 

net weight is calculated. 

With a tare mechanism, the gross and tare weights are measured from gross zero and the net weight is 

measured from net zero. Mathematical agreement cannot be guaranteed in cases where the instrument 

measures all three values, since rounding errors may result in disagreement by +1 division 12.5 % of the 

time and -1 division 12.5 % of the time. Forcing mathematical agreement would require the manufacturer 

to fudge the results. Consider the following case:

Load Internal Value Rounded Value

Gross 4.317 lb 4.32 lb

Tare 0.034 lb 0.03 lb

Net 4.283 lb 4.28 lb (No agreement as G – T = 4.29 lb)

In this case the gross weight is rounded up and the tare weight is rounded down, resulting in a measured 

net weight 0.01 lb (1 d) smaller than the calculated net value. Similarly, if the gross weight is rounded up 

and the tare weight rounded down, the measured net weight is 0.01 lb (1 d) greater than the calculated net 

weight. Because these changes may be significant, they are proposed as nonretroactive.

There is a disconnect between mathematical agreement and tolerance application to net weight. If the net 

weight is calculated from measured gross and net weights, then mathematical agreement is required but 

tolerance is not applied to net weight. If the net, gross and tare weights are all measured, then 

mathematical agreement is not required but tolerance is applied to the net weight value. See proposed 

changes to T.N.2.1.

Regarding T.N.2.1. General.

Justification: The changes are clarifications and thus do not affect retroactivity. The addition of language 

applying the tolerances to errors of overregistration and underregistration insures uniform application of 

the signs. An instrument with a + error of overregistration also has a – error in deficiency. We should be 

consistent with G-T.3. and all report errors the same way. The tradition is to apply tolerances to errors of 

over/underregistration. The last part of the first sentence is deleted since the test may begin at other than 

zero at no load. For example, tolerance may be applied to net values that begin at zero at tare load with a 

tare mechanism in operation. 

The new text spells out four instances where tolerances are applied. This includes:

1. Errors in gross indications, beginning at gross load zero. – This has always been the case. These 

weighings begin at dead load zero. Note that the zero setting is covered by proposed S.1.1.1.(b) 

which requires setting zero accurate to 1⁄4 e.
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2. Errors in net indications, beginning at net load zero when using a tare mechanism. – This also has 

traditionally been the practice even in the Scales Code pre-1984. This net zero setting is also 

accurate to 1/4 e per proposed S.1.1.1.(b). The current wording is ambiguous.

3. Errors in Tare indications displayed on a dedicated tare weighing mechanism when a tare 

mechanism is in operation. – A good example is a dedicated tare weighbeam with a locking poise. 

Without this statement, you could not apply tolerances to the indication of the tare weighbeam. 

With an electronic scale, the dedicated tare display is rare, but the approach is the same as the 

dedicated weighbeam. A digital value in the tare display will be transferred from the gross 

weight display when the tare mechanism is activated. We expect the value to match the original 

gross weight exactly, and thus tolerances should apply. This does not apply to a preset tare since 

a preset tare is not actually weighed, but introduced externally. Also remember that the tare 

display will remain at the same value, regardless of the load on the load receptor, until another 

tare mechanism is activated, or the tare is cleared. 

4. Errors in net values recorded on a dynamic monorail scale. – The dynamic monorail is a unique 

case since these instruments only record net weight. In OIML these devices are not part of R76 

on which the Scales Code is based, but rather R51. The text further clarifies that tolerances are 

not applied to net values on other types of scales when a preset tare is in operation.

5. The graphic highlights the difference between tare and preset tare devices. The values are in d. In 

the example, the gross value of the tare is about 3.4 d. When using a tare mechanism, the center 

of net zero is set at the gross value of 3.4 d. If the tare is removed the no load is at -3.4 d. With a 

tare mechanism the net divisions may not align with the gross divisions since the tare may not be 

a whole number of d. 

With a preset tare mechanism, the rounded value of the tare entry is subtracted from the gross weight. 

This results in a net scale that aligns with the gross scale but is offset by the rounded value of the tare.

With keyboard tare, the tare is entered at gross zero, resulting in an indication of -3 d. With a 

programmed tare like a POS system, the rounded gross weight is displayed and the 3 d tare associated 

with the PLU is subtracted before the net weight is printed. The preset tare may have an inherent 

rounding error of up to 0.5 d from the actual tare weight. In addition, any error in the instrument gets 

added to this rounding error. By not applying tolerances you do not penalize the instrument for these two 

errors. Remember that the user may be cited for misrepresentation of the quantity (UWML §15, if the 

wrong preset tare is entered. Also, you can use the tare mechanism to test the instrument accuracy in net 

mode. This is what was intended in the current language of T.N.2.1. referring to “any possible tare load 

using certified weights.” That is, applying a known weight and using the semi-automatic tare to set the 
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net zero. In the R76 test in net mode, the applied tare load is chosen near the break point between 

divisions to verify that the net zero is set accurate to 1⁄4 e.

NIST OWM Executive Summary for SCL-24.2. − Multiple Sections Regarding Tare

NIST OWM Recommendation: Developing/Assigned

• NIST OWM recognizes the issues raised by the submitter and is of the opinion that the 

proposed amendments help solve these issues. However, as the submitter already indicated, 

the item is not yet fully developed. NIST OWM supports further development of the item, 

either by the submitter or by a task group.

Table 2. Summary of Recommendations

SCL-24.2. − Multiple Sections Regarding Tare

Status Recommendation Note* Comments

Submitter Developing

OWM Developing or Assigned

WWMA Developing

NEWMA Developing

SWMA Withdrawn

CWMA Developing

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered
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Item Under Consideration:

(NIST OWM has applied the appropriate formatting according to NIST Handbooks)

Amend Handbook 44 Scales Code and Appendix D, Definitions as follows:

Appendix D, Definitions:

tare mechanism. – A mechanism (including a tare bar) designed for determining or balancing out the 

weight of packaging material, containers, vehicles, or other materials that are not intended to be 

included in net weight determinations. A mechanism for setting the indication to zero when a load 

is on the load receptor, either without altering the weighing range for net loads (additive tare 

mechanism); or reducing the weighing range for net loads (subtractive tare mechanism). It may 

function as a non-automatic mechanism (load balanced by an operator), or a semi-automatic 

mechanism (load balanced automatically following a single manual command). [2.20] 

(Amended 20XX)

Add new definitions as follows:

preset tare mechanism. – A mechanism for subtracting a numerical value, (representing a 

weight, that is introduced into the instrument and is intended to be applied to other weighings 

without determining individual tares) from a gross or net weight value and indicating the result 

of the calculation. The weighing range for net loads is reduced accordingly. “Introduced” 

includes procedures such as: keying in, recalling from a data storage device, or inserting via an 

interface. [2.20] 

(Added 20XX)

gross indication. – The indication of a weighing instrument with no tare mechanism or preset 

tare mechanism in operation. [2.20]

(Added 20XX)

gross load. – (1) All materials placed on the load receptor exclusive of the load receptor itself, or 

(2) the combined commodity and tare materials placed on the load receptor. [2.20]

(Added 20XX)

gross weight. – A weight value assigned to the combination of commodity and tare in a 

commercial transaction. [2.20] 

(Added 20XX)

net indication. – The indication of a weighing instrument with a tare mechanism or preset tare 

mechanism in operation. [2.20]

(Added 20XX)

net load. – All commodity materials placed on the load receptor. [2.20]

(Added 20XX)

net weight. – A weight value assigned to the commodity in a commercial transaction. [2.20]

(Added 20XX)
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tare indication. – The indication of a tare weighing mechanism. [2.20]

(Added 20XX)

tare weight. A weight value assigned to the tare in a commercial transaction. [2.20]

(Added 20XX)

tare load. – All tare materials placed on the load receptor. [2.20]

(Added 20XX)

Scales Code changes:

S.1.1.1. Digital Indicating Elements.

(a) A digital zero indication shall represent a balance condition that is within ± 1⁄2 the value of the 

scale division.

(b) After zero setting the effect of zero deviation on the result of the weighing shall be not 

more than ± 0.25 e. 

[Nonretroactive as of January 1, 20XX]

(Added 20XX)

(c) A digital indicating device shall either automatically maintain a “center-of-zero” condition 

to ± 1⁄4 scale division or less, or have an auxiliary or supplemental “center-of-zero” 

indicator that defines a zero-balance condition to ± 1⁄4 of a scale division or less. A “centerof-zero” indication may operate when zero is indicated for gross and/or net mode(s). A 

digital indicating device shall have a “center-of-zero” indicator that indicates when the 

deviation from zero is not more than ± 1⁄4 verification scale division. A “center-of-zero” 

indication may operate when zero is indicated for gross and/or net mode(s). The “centerof-zero” indicator is not mandatory on a device equipped with an auxiliary indicating 

device or equipped with a zero-tracking mechanism.

[Nonretroactive as of January 1, 1993]

(c)(d) For electronic cash registers (ECRs) and point-of-sale systems (POS systems) the display of 

measurement units shall be a minimum of 9.5 mm (3/8 inch) in height. 

[Nonretroactive as of January 1, 2021]

(Added 2019)

(Amended 1992, 2008, and 2019, and 20XX)

...

S.1.2.1. Digital Indicating Scales, Units. – Except for postal scales, a digital-indicating scale shall 

indicate weight values using only a single unit of measure. Weight values indications 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.

The requirement that the value of the scale division be expressed only as 1, 2, or 5, or a decimal 

multiple or submultiple of only 1, 2, or 5 does not apply to net weights indications and recorded 

representations that are calculated from gross and tare weights (measured without use of a tare or 

preset tare mechanism) indications where the scale division of the gross weight is different from the 
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scale division of the tare weight(s) on multi-interval or multiple range scales. For example, a 

multiple range or multi-interval scale may indicate and record tare weights in a lower weighing 

range (WR) or weighing segment (WS), gross weights in the higher weighing range or weighing 

segment, and calculated net weights as follows:

55 kg Gross Weight (WR2 d = 5 kg) 10.05 lb Gross Weight (WS2 d = 0.05 lb)

–

4 kg

Tare Weight (WR1 d = 2 kg) –

0.06 lb

Tare Weight (WS1 d = 0.02 lb)

= 

51 kg

Net Weight (Mathematically 

Correct)

= 

9.99 lb

Net Weight (Mathematically 

Correct)

[Nonretroactive as of January 1, 1989]

(Added 1987) (Amended 2008 and 20XX)

...

S.1.7. Capacity Indication, Weight Ranges, and Unit Weights.

(a) Gross Capacity. – An indicating or recording element shall not display any values nor record 

any values when the gross load (not counting the initial dead load that has been canceled by 

an initial zero-setting mechanism) is in excess of 105 % of scale capacity.

(b) Capacity Indication. – Electronic computing scales (excluding postal scales and weight 

classifiers) shall neither display nor record a gross or net weight values not display any 

values nor record any values when the gross load (not counting the initial dead load that 

has been canceled by an initial zero-setting mechanism) is in excess of scale capacity plus 

9 d.

[Nonretroactive as of January 1, 1993]

The total value of weight ranges and of unit weights in effect or in place at any time shall 

automatically be accounted for on the reading face and on any recorded representation.

This requirement does not apply to: (1) single-revolution dial scales, (2) multi-revolution dial scales 

not equipped with unit weights, (3) scales equipped with two or more weighbeams, nor (4) devices 

that indicate mathematically derived totalized values.

(Amended 1990, 1992, and 1995, and 20XX)

...

S.2.3. Tare Mechanism and Preset Tare Mechanism, General. – On any scale (except a 

monorail scale equipped with digital indications and multi-interval scales or multiple range scales 

when the value of tare weight is determined in a lower weighing range or weighing segment), the 

value of the tare division shall be equal to the value of the scale division.* The tare mechanism or 

the preset 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. *

[*Nonretroactive as of January 1, 1983]

(Amended 1985, and 2008, and 20XX)
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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. Tare Mechanism. – A tare mechanism shall permit setting the indication to zero 

accurate to ± 0.25 e. On a multi-interval device e shall be replaced by e1.

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

S.2.3.2. Preset Tare Mechanism. – Regardless of how a preset tare value is introduced, its 

scale division shall be equal to or automatically rounded to the scale division of the device. On 

a multiple range device, a preset tare value may only be transferred from one weighing range 

to another one with a larger verification scale division but shall then be rounded to the latter. 

For a multi-interval device, the preset tare value shall be rounded to the smallest verification 

scale division, e1, of the device, and the maximum preset tare value shall not be greater than 

Max1. The displayed or printed calculated net value shall be rounded to the scale interval of the 

device for the same net weight value. 

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

...

S.1.15. Marking of Weight Indications. 

(a) A single display used only for gross indications need not be designated. The display may 

be designated by the term “gross.”

(b) A single display used for both gross and net values shall be designated “net” when 

displaying the net value while a tare mechanism or preset tare mechanism is in 

operation. The display may be designated “gross” when no tare mechanism is in 

operation, or when the gross weight is temporarily indicated while a tare mechanism is 

in operation. 

(c) If an instrument simultaneously displays two or more of the net, gross, or tare 

indications, each display shall be designated by the appropriate term “net,” “gross,” or 

“tare.” 

(d) However, it is permitted to replace the terms net, gross, and tare with the appropriate 

designations “N” for net, “G” for gross and “T” for tare displayed to the right of the 

weight values, e.g., 4.48 lb N, 4.52 lb G, or 0.04 lb T.

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

S.1.16. Printing of Weighing Results. 

(a) Gross weights may be printed without any designation. For a designation by the symbol, 

only “G” is permitted. 
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(b) f only net weight is printed without corresponding gross or tare values, it may be 

printed without any designation. A symbol for designation shall be “N”. 

(c) Gross, net, or tare weights determined by a multiple range instrument or by a multiinterval instrument need not be marked by a special designation referring to the 

(partial) weighing range. (see also S.1.2.1.)

(d) If net weights are printed together with the corresponding gross and/or tare weights, the 

net and tare weights shall at least be identified by the corresponding symbols “N” and 

“T”. If the gross weight is identified, the symbol “G” shall be used.

(e) However, it is permitted to replace “G”, “N” and “T” by complete words in English. 

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

S.1.17. Mathematical Agreement of Net, Gross and Tare Values. – When a device 

simultaneously indicates (or records) net, gross and tare indications, the values shall be in 

mathematical agreement based on the formula Net Weight = Gross Weight – Tare Weight 

whenever one of the three values is calculated from two measured weight values, e.g., calculated 

Net = weighed Gross – weighed Tare. Mathematical agreement is not required due to potential 

rounding errors when all three values are independently measured.

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

Alternative proposal.

S.1.17. Mathematical Agreement of Net, Gross and Tare Values. – When a device 

simultaneously indicates (or records) net, gross and tare indications, the values shall be in 

mathematical agreement based on the formula Net Weight = Gross Weight – Tare Weight, 

whenever one of the three values is calculated from two measured weight values, e.g., calculated 

Net = weighed Gross – weighed Tare. This also applies to calculated net weights when a preset 

tare mechanism is in operation. Mathematical agreement is not required due to potential rounding 

errors when a tare mechanism is in operation, as all three values are independently measured.

(Nonretroactive as of January 1, 20XX)

(Added 20XX)

...

T.N.2.1. General. – The tolerance values are positive (+) and negative (−) herein prescribed shall 

be applied to errors of overregistration and underregistration. with the weighing device 

adjusted to zero at no load. When tare is in use, the tolerance values are applied from the tare 

zero reference (zero net weight indication); the tolerance values apply to the net weight 

indication for any possible tare load using certified test loads. The tolerances apply to 1) errors 

in gross indications (starting at gross load zero), 2) errors in net indications (starting at net load 

zero) when a tare mechanism is in operation, 3) errors in tare indications on a dedicated tare 
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display when a tare mechanism is in operation, and 4) errors in net indications on a dynamic 

monorail scale (using a preset tare mechanism). Tolerances do not apply to errors in net 

indications for scales other than on dynamic monorail scales, when a preset tare mechanism is 

in operation.

(Amended 2008 and 20XX)

NIST OWM Detailed Technical Analysis: 

S.1.2.1 in the current scale code suggests that when tare is applied, the values of Tare, Net and Gross must 

be in mathematical agreement, i.e., Tare + Net = Gross. This means that one of these values is always a 

calculated value from two rounded weight values. S.1.2.1 suggest that the Net value is calculated from 

the Gross value and the Tare value:

Net = Gross – Tare

The consequence of the requirement of mathematical agreement is that the calculated value has a 

rounding error. On a normal single interval scale, this rounding error can be as big as 0.5 e. If the 

calculation is performed as suggested in the example of S.1.2.1 then this rounding error occurs in the Net 

value while this is the value that is used for the transaction.

Example 1:

A scale with e = 1 g 

The actual tare value = 10.5 g and the actual net = 20.9 g

=> The actual gross = 10.5 g + 20.9 g = 31.4 g

Indication rounded to e:

Gross = 31 g, Tare = 11 g

Net calculation due to mathematical agreement:

Net = Gross – Tare = 31 – 11 = 20 g

The indication is 20 g while in reality it should be 21 g.

When using flip weights to determine the error in the Net value, the Net indication changes at the first 

flip weight, indicating an error of -0.5 e. This error, due to rounding only, is equal to the acceptance 

tolerance. On top of this rounding error, there is the intrinsic error (the inaccuracy) of the scale.

On a multi-interval scale this problem is even bigger.

Example 2:

A multi-interval scale to fill propane tanks: 6/15 kg x 2/5 g

The tank weighs 7.003 kg and the propane weighs 0.999 kg

=> The actual gross = 7.003 kg + 0.999 kg = 8.002 kg
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Indications rounded to e:

Gross = 8.000 kg (e=5 g)

Tare = 7.005 kg (e=5 g)

Net calculation due to mathematical agreement:

Net = Gross – Tare = 8.000 kg – 7.005 kg = 0.995 kg

Because the net value falls in the lower range, its corresponding scale division, e is 2 g. The 

acceptance tolerance is 0.5 e = 1 g.

The difference between the indication and the true value is 4 g which is 4x the acceptance 

tolerance.

The current language in the scale code and our test procedures have several shortcomings that facilitate 

the problem of rounding errors and create non-uniformity:

1) The rule that Gross, Tare and Net must be mathematical agreement is generally applied but there 

is no such requirement in HB44. Only the example in S.1.2.1 seems to suggest that they must be 

in mathematical agreement, but a clear requirement is missing.

2) There is a general rule that rounding must be the very last operation. However, mathematical 

agreement forces to first round two weight values and then calculate the third one. This is the 

only way to guarantee mathematical agreement. Therefore, in the tare calculation, rounding is 

NOT the final operation.

3) The rule of mathematical agreement requires that one of the values is a calculated value, but the 

code does not specify which value shall be calculated. This leads to different implementations of 

the tare operation on instruments in the field.

4) S.1.2.1 suggests that the Net value should be the calculated value. However, this is the value that 

is used for the commercial transactions. Of the three values, rounding of the Gross value would 

have the least impact and would therefore be a better choice to be the calculated value.

5) The size of the rounding error depends on the actual loads. Since tests are normally performed 

with test loads equal to an exact number of scale divisions, (e.g., a tare weight of exactly 50 e and 

a net load of 200 e), the rounding error is zero (or close to zero) and the problem remains hidden. 

A better way to test the tare function on a scale is to use a tare weight close to the changeover 

point between to indications.

6) There is no requirement for error at Net zero to be within 0.25 e. If the rounding error is applied 

to the Net value, this often manifests itself in an error at Net zero. Unfortunately, currently there 

is no requirement that the Net zero must be within 0.25 e after activating Tare (or after zerosetting). Hence there is no test for checking whether Net zero is within 0.25 e and this problem is 

not detected in the field.

7) The rounding error varies between – 0.5 to + 0.5 scale divisions (d, not e). That means that when 

the scale is placed in high resolution mode for testing where d = 1/10 of e, the rounding error is at 

max 0.5 d which is equal to 0.05 e and well within tolerance. Hence, the problem remains 

undetected. The only way to make this problem visible is by testing it in normal resolution.
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SCL-24.2 is an attempt to address these shortcomings. NIST OWM supports the item in an effort to 

avoid rounding errors in weight values used in commercial transactions and to increase uniformity in the 

implementation of tare functionality.

That being said, NIST OWM does not think the item has been fully vetted yet and supports a developing 

status.

Regional Association Reporting:

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, Cory Hainy (SMA) remarked the association has not met on this 

item and intends to review it in the November 2023 SMA meeting.

Steve Harrington (Oregon) expressed concerns regarding terminology throughout the item but 

acknowledged that there is merit to the item. They recommend this item be separated by the appropriate 

sections that would correspond to the handbook and that the items be blocked together. They also 

recommend this item be assigned a developing status.

Kevin Schnepp (California) echoed the comments from Oregon, supports a developing status, and looks 

forward to comments from the SMA.

The WWMA S&T Committee recommends that this item be assigned a Developing status. This will 

allow the submitter the opportunity to address the comments heard during the open hearings and receive 

feedback from stakeholders. The WWMA S&T Committee further recommends the items be separated 

and Blocked, specifically separating the Scale Code sections into one item and the definitions sections 

into a second item.

As a point of technical merit, proposed items are best presented when they are specific and clear for the 

body to evaluate the proposal accurately. This comment is in reference to specifically the alternative 

proposal of S.1.17 found on page S&T – 227 of the WWMA 2023 S&T Agenda. This Committee 

recommends the submitter determine which version of S.1.17 best fits this proposal for merit and remove 

the other version.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Cory Hainy (SMA) stated they have not reviewed the item. The 

Committee disagrees with the justification and the use of alternate proposals within the item.

The Committee recommends the item be Withdrawn.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, a regulator from Holliston, Massachusetts stated the Cannabis TG 

is working with the Scale Verification Task Group. A meeting was scheduled for mid-September. The 

Cannabis TG hopes to have something finalized for the Interim meeting. The State of New York supports 

further development and it is necessary for clarification. There was discussion of assigning this item to 

the Scale Verification Task Group but it was noted that there would have to be a change of scope. Upon 

consensus of the body, the Committee recommends this item be Developing.
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Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Developing and seeks input from industry stakeholders. 

SCL-22.3 D UR.3.3. Single-Draft Vehicle Weighing, and UR.3.4. Axle and Axle Group 

Weight Values.

(Note: At the 2023 Interim Meeting, the Committee agreed to remove this item from Block 6.)

Source: NIST Office of Weights and Measures

Submitter’s Purpose and Justification:

This proposed change is intended to add clarification regarding the implications of using weighing and 

measuring devices for transactions that may be considered by some as commercial while there is no clear 

guidance provided.

NIST OWM Executive Summary for SCL-22.3 – Single-Draft Vehicle Weighing and UR.3.4. Axle 

and Axle Group Weight Values.

NIST OWM Recommendation: Voting, with the recommended edits as indicated below

• The adoption of GEN-22.1 in 2022, which amended paragraph G-A.1. Commercial and LawEnforcement Equipment of NIST Handbook 44 clarifying that weighing and measuring 

equipment used for the purpose of providing a weight or measure for a fee constitutes 

commercial use of that equipment, necessitated this proposal.

• The WWMA & NEWMA regions had concerns with “split-weighing”:

o SCL-22.1 was adopted at the 2023 NCWM Annual Meeting and adds paragraph S.1.15. to 

NIST Handbook 44 requiring the recorded value be identified as “Not-Legal-For-Trade” 

when not all weights value were determined simultaneously (split-weighed).

o Paragraph UR.3.3. will still require a vehicle or vehicle combination to be weighed 

“commercially” as a single draft except as noted in subparts (a) and (b) of the paragraph.

o The “Note” in UR.3.3. currently exempts highway-law-enforcement scales and scales used 

for the collection of statistical data from having to weigh in single drafts. This item would 

add another exemption to this paragraph for scales used to weigh axle loads, axle-group 

loads, and the gross weight of vehicles and coupled-vehicle combinations for a fee, when 

those values are only used “to determine compliance with highway legal load limits and 

safe distribution of the load”.

o SCL-22.3 also adds a new paragraph, UR.3.4. which clarifies that it is acceptable to use 

multi-platform vehicle scale systems to charge a fee for the commercial service of 

providing customers (usually truckers) axle weights, axle group weights, and the gross 

weight of their vehicles to enable them to determine compliance with state and federal legal 

load limits.
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NIST OWM Executive Summary for SCL-22.3 – Single-Draft Vehicle Weighing and UR.3.4. Axle 

and Axle Group Weight Values.

o In addition, this new UR.3.4. paragraph clarifies how these weights must be obtained to 

be used as commercial values, i.e., the summed total of a vehicle that is “splitweighed” cannot be used as the basis for a commercial transaction.

• OWM proposed amendments to this item in May 2023 based on feedback received from the 

SMA during and after the 2023 NCWM Interim Meeting and requested that the Committee 

replace the current proposal in SCL-22.3. The item under consideration reflects these 

amendments.

• OWM suggests the following minor edits:

o Remove the word “axle-“ throughout the item and replace it with “axle load” instead of 

“axle-“ not including the term “axle-group loads”.

o Add the word “established” between the words “with” and “highway” in the last paragraph 

of UR.3.3., formerly the “Note”.

o Remove the “s” from “subparts” in the last paragraph of UR.3.4.

o Add the amended date to paragraph UR.3.3. and the added date to UR.3.4.

o The item would then appear as this:

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, the weight of:

(a) a coupled combination may be determined by uncoupling the various elements (tractor, 

semitrailer, trailer), weighing each unit separately as a single draft, and adding together the 

results; or

(b) a vehicle or coupled-vehicle combination may be determined by adding together the 

weights obtained while all individual elements are resting simultaneously on more than 

one scale platform.

Note: This paragraph does not apply to highway-law-enforcement scales, and scales used for 

the collection of statistical data, or scales used to charge a fee for the service of providing 

weights of the different axle loads, axle-group loads, and total weight of vehicles and 

coupled-vehicle combinations when the only use of those values is to determine 

compliance with established highway legal load limits and safe distribution of the load. 

(Added 1992) (Amended 20XX)

And
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NIST OWM Executive Summary for SCL-22.3 – Single-Draft Vehicle Weighing and UR.3.4. Axle 

and Axle Group Weight Values.

UR.3.4. Weighing of Axle Loads and Axle-Group Loads – Establishing weight values for the 

different individual axle loads and axle-group loads of a vehicle or coupled-vehicle combination 

is oftentimes necessary to verify compliance with established highway weight requirements and 

safe distribution of the load. When a fee is charged for this service, the scale’s application is 

considered “commercial” under the provisions of paragraph G-A.1. Commercial and Law 

Enforcement Equipment and the scale shall comply with all applicable NIST Handbook 44 

requirements for commercial weighing systems. 

When weight values for axle loads and/or axle-group loads are obtained using multipleindependent platform vehicle scale systems in which all parts of the vehicle or coupled-vehicle 

combination being weighed are simultaneously positioned on live elements of the scale, the 

values for the different axle loads and axle-group loads may be summed to establish the legal 

gross vehicle weight. 

In no case, however, shall a summed result of the different axle loads and axle-group loads of 

a vehicle or coupled vehicle combination weighed in multiple drafts be used as the legal gross 

weight unless subpart (a) or (b) of paragraph UR.3.3. Single-Draft Vehicle Weighing is met.

(Added 20XX)

• With these minor edits OWM requests a Voting status

• OWM notes this item is currently in a “Developing” status. OWM encourages a review of the 

most current proposal and continues to seek feedback from all interested parties or individuals. 

Table 2. Summary of Recommendations

SCL-22.3 Single-Draft Vehicle Weighing and UR.3.4. Axle and Axle Group Weight Values

Status Recommendation Note* Comments

Submitter (OWM) Voting

WWMA Developing

NEWMA Developing

SWMA Voting

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language
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2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Scales Code as follows: 

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, the weight of:

(a) a coupled combination may be determined by uncoupling the various elements (tractor, 

semitrailer, trailer), weighing each unit separately as a single draft, and adding together the 

results; or

(b) a vehicle or coupled-vehicle combination may be determined by adding together the weights 

obtained while all individual elements are resting simultaneously on more than one scale 

platform.

Note: This paragraph does not apply to highway-law-enforcement scales, and scales used for the 

collection of statistical data, or scales used to charge a fee for the service of providing weights 

of the different axle-, axle-group loads, and total weight of vehicles and coupled-vehicle 

combinations when the only use of those values is to determine compliance with highway 

weight requirements and safe distribution of the load. 

(Added 1992) (Amended 20XX)

And

UR.3.4. Weighing of Axle- and Axle-Group Loads – Establishing weight values for the different 

individual axle- and axle-group loads of a vehicle or coupled-vehicle combination is oftentimes 

necessary to verify compliance with established highway weight requirements and safe 

distribution of the load. When a fee is charged for this service, the scale’s application is 

considered “commercial” under the provisions of the General Code paragraph G-A.1. 

Commercial and Law Enforcement Equipment and the scale shall comply with all applicable 

NIST Handbook 44 requirements for commercial weighing systems. 

When weight values for axle- and/or axle-group loads are obtained using multiple-independent 

platform vehicle scales systems where all parts of the vehicle or coupled-vehicle combination 

being weighed are simultaneously positioned on live elements of the scale, the values for the 

different axle- and axle-group loads may be summed to establish the legal gross vehicle weight. 

In no case, however, shall a summed result of the different axle- and axle-group loads of a vehicle 
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or coupled vehicle combination weighed in multiple drafts be used as the legal gross vehicle 

weight unless subparts (a) and (b) of paragraph UR.3.3. Single-Draft Vehicle Weighing.

(Added 20XX)

Renumber existing paragraphs UR.3.4 through UR.3.12.

NIST OWM Detailed Technical Analysis: 

OWM developed two proposals, SCL-22.1 (adopted in 2023) and SCL-22.3, to address gaps in NIST 

Handbook 44 Scales Code requirements pertaining to the design and use of multi-independent platform 

vehicle scale systems commercially used to charge a fee for the service of determining axle and axlegroup weights, as well as the gross vehicle weight. These proposals were developed as the result of an 

OWM inquiry from a state questioning the permissible use of a multi-independent platform vehicle scale 

system (each platform having its own A/D conversion circuitry and weight indicator) that printed gross 

vehicle weights from summing the axle loads and axle-group loads of vehicles weighed when not all parts 

of those vehicles were able to fit onto a live portion of the scale and be weighed simultaneously. That is, 

the scale was being used on occasion to “split weigh” (weigh in multiple drafts) the axle and axle groups 

of “over-sized” coupled-vehicle combinations because not all axle and axle groups could be positioned 

simultaneously on the live portion of the scale.

These systems are most often used commercially to verify compliance with federal and state vehicle load 

limits but at times may also be used to establish the net loads of products that are bought and sold by 

weight, to establish transportation charges, or for other commercial purposes. While the printed ticket for

those weight determinations may provide clear indication that the gross vehicle weight value recorded 

was “non certifiable,” it is questionable whether this is permitted since HB 44 Scales Code paragraph 

UR.3.3. Single-Draft Vehicle Weighing requires a vehicle or coupled-vehicle combination to be 

commercially weighed on a vehicle scale only as a single draft. Note: A manufacturer of a particular 

scale system advised us that most vehicles and coupled-vehicle combinations that are weighed on this 

type of scale can be weighed as a single draft. It is only the occasional oversized vehicle or coupledvehicle combination that exceeds the length of the scale and must therefore be split weighed.

We purposely chose to simplify these proposals to only address multi-independent platform vehicle scale 

systems. These systems have been installed at truck stops (and perhaps other locations) throughout the 

US for many years and are used primarily to determine axle loads, axle-group loads, and gross vehicle 

weight of vehicles and coupled-vehicle combinations for a fee. Although we recognize that singleplatform vehicle scales may sometimes be used for this same purpose, we don’t view them as being 

suitable for the application. This is because the approach requirements for vehicle scales and axle-load 

scales in NIST HB44 are very different and few vehicle scales in commercial service have approaches 

that comply with the approach requirements for axle-load scales. Axle-load scales are required to have a 

straight paved approach in the same plane as the platform on each end of the platform. The approaches 

must be the same width as the platform and of sufficient length to ensure the level positioning of vehicles 

during weight determinations. If vehicles aren’t level when the different axle and axle groups are 

weighed, a portion of the force of the load transfers to other axle and axle groups that aren’t positioned on 

the scale resulting in false weight. It is important to recognize that not all multi-independent platform 

vehicle scale systems may be installed with approaches meeting the HB 44 approach requirements for an 

axle-load scale. Many do, but we are unable to confirm that all do. We view this as an important concern 

given that these proposals, if adopted, would make it permissible to split weigh vehicles and coupledvehicle combinations for a fee, provided that the weighing results are used only to verify that the different 

axle, axle-group loads, and gross vehicle weight are compliant with highway weight limits.
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Another reason we elected to limit these proposals to only address multi-independent platform vehicle 

scale systems is that we do not believe it suitable to use single-platform vehicle scales to determine axle 

loads and axle-group loads of vehicles and coupled-vehicle combinations to verify compliance with 

federal and state vehicle load limits. Those that are using them for this purpose usually don’t charge a fee, 

i.e., the weighing is usually done as a complimentary service. 

NIST HB 44 does not currently require a multi-independent platform vehicle scale system to be equipped 

with a ticket printer and whether or not one should be required, is something to be considered. We have 

not proposed it, but perhaps others will conclude this would be an important HB 44 addition. We believe 

most (perhaps all) of the multi-independent platform vehicle scale systems currently in commercial 

service have been equipped with a ticket printer and this is likely because the few scale manufacturers of 

these systems recognize the need for the multiple indications displayed by these systems to be made 

available in printed form to the operator and customer.

We also believe most of the systems currently in service comply with the newly adopted sub-paragraphs 

of S.1.15. We developed these two new sub-paragraphs (S.1.15.1. and S.1.15.2.) because it is important 

for scale operators, customers, and enforcement officials to be able to clearly identify from a weigh ticket 

the different scale platforms utilized at the time a vehicle was weighed and their corresponding scale 

indications so that the accuracy of those values (including the summed total) can be verified. It is also 

important to clearly specify, on a weigh ticket generated from one of these scale systems, that any 

recorded gross vehicle weight value determined from summing the different axle and axle-group loads of 

a vehicle or coupled-vehicle combination weighed in multiple drafts (i.e., split weighed) is “Not-LegalFor-Trade.” 

Paragraph UR.3.3. needs to be amended to address the current use of multi-independent vehicle scale 

systems to split weigh oversized vehicles for a fee. When used to provide a gross vehicle weight that 

determines compliance with maximum legal load limits and safe distribution of the load this is an 

acceptable practice. Years ago, (prior to the existence of multi-independent platform vehicle scale 

systems) axle-load scales served this same purpose at truck stops throughout the US and summing of the 

different axle and axle groups to determine gross vehicle weight undoubtedly occurred when using those 

scales to ensure vehicles didn’t exceed maximum legal load limits. For these reasons, OWM has 

provided the Committee this proposal to add paragraph UR.3.4. to the Scales Code, which would make it 

permissible to weigh in multiple drafts (i.e., split weigh) a vehicle or coupled-vehicle combination and 

charge a fee for the service of providing weights of the different axle- and axle-group loads when the only 

use of those values is to determine compliance with highway legal load limits.

Summary of Discussions and Actions:

During open hearings at the 2022 NCWM Annual Meeting, Richard Harshman (NIST OWM) provided 

the Committee a high-level summary of its analysis of the two remaining items in Block 6, which 

included much of background information that had led OWM to submit the two proposals in Block 6 as 

well as the GEN-22.1 G.A.1. Commercial and Law-Enforcement Equipment item, which the Committee 

had previously removed from Block 6. Richard Harshman reported that OWM had recently provided the 

Committee an updated version of the proposal in SCL-22.1 and requested the Committee replace the 

version of SCL-22.1 in its current agenda with the updated version recently received. Richard Harshman

also reported that OWM planned to revise the proposal in SCL-22.3 and would later (sometime following 

the 2022 NCWM Interim Meeting) submit the revised version to the Committee in hopes it could be 

reviewed by one or more of the regional weights and measures associations meeting in the Spring and/or 
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fall of 2022. Richard Harshman recommended both items remain in a developing status to allow 

stakeholders time to review and recommend any changes they felt necessary.

Russ Vires (Mettler Toledo LLC) speaking on behalf of the SMA reported that the SMA recommends 

Block 6 be broken apart into three individual items (i.e., GEN-22.1 Commercial and Law-Enforcement 

Equipment, SCL-22.1 Recorded Representation of Axle or Axle Group Weights, and SCL-22.3 UR.3.3. 

Single-Draft Vehicle Weighing and UR.3.4. Axle and Axle Group Weight Values). Russ Vires then 

provided the SMA’s position and rationale for each of these items speaking verbatim from the SMA’s 

November 2, 2021 report titled “SMA Positions on the NCWM Specification and Tolerances Committee 

Report (For the NCWM Interim Meeting, January 2022, Developed November 2, 2021). NIST Technical 

Advisors note: Refer to the subheading shown below titled, “Scale Manufacturers Association (SMA-Fall 

2021 Meeting)” to view the different positions and rationales provided by Russ Vires on behalf of the 

SMA for the items in Block 6. Russ Vires also reported that the SMA had had the opportunity during its 

Fall 2021 meeting to review the updated version of the proposal in SCL-22.1 that OWM had provided the 

Committee for replacement of the one in its current agenda and that the SMA supported the changes 

OWM had made.

These were several officials who spoke in support of further development of the two items in Block 6. 

Lou Straub (Fairbanks Scale) reported that Fairbanks Scale had been manufacturing the multi-platform 

“CAT” vehicle scale system for over forty years and the systems had been installed in approximately 

2,000 locations. They also reported that they fully supported the GEN-22.1 item that the Committee had 

earlier removed from Block 6. Referencing the proposal in SCL-22.1, Lou Straub agreed that the 

recorded representation of weights from individual axle or axle groups need to be clearly identified as 

“not-legal-for- trade” on the printed ticket unless the entire vehicle is positioned on live elements of the 

vehicle scale system and all axles/axle groups are weighed simultaneously. They voiced disagreement

with the second sentence proposed in paragraph S.1.14. noting that when one considers a truck with six to 

eight axle groups that cannot fit onto the different independent platform and be weighed simultaneously, 

identifying which platform weighed each of these axle and axle groups becomes unnecessary. 

The Committee, in consideration of the comments received during open hearings, agreed to replace the 

Block 6 SCL-22.1 proposal in its Interim Meeting agenda (2022 NCWM Publication 15) with the updated 

version provided by OWM just prior to the 2022 NCWM Interim Meeting and maintain a developing 

status on the two remaining items in Block 6. The following proposal represents the Block 6 SCL-22.1 

item appearing in the 2022 version of NCWM Publication 15 that the Committee agreed to replace with 

the Item under Consideration now shown in SCL-22.1:

Item under Consideration as it appeared in the 2022 NCWM Publication 15:

Amend Handbook 44, Scales Code as follows: 

S.1.14. Recorded Representation of Axle or Axle Group Weights. – The recorded 

representation of weights from individual axle or axle group weights shall clearly be identified 

as “not legal for trade” or “non-commercial” weight values unless the entire vehicle is 

positioned on live elements of a multiple-platform vehicle scale and where all axles/axle groups 

are weighed simultaneously. All recorded weights of axles/axle groups shall be identified as 

representing only a portion of the vehicle’s total gross weight (e.g., by axle groupings such as: 

“axle group 1,” “axle group 2,” “axle group 3,” or by individual axle description such as: 

“steering axle,” “drive axles,” “trailer axles”).
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Any total gross weight of the vehicle included in the recorded representations determined by 

summing axle weights shall be clearly identified as “not-legal-for trade” or “non-commercial” 

unless those axle weights were recorded when all parts of the vehicle rested simultaneously on 

live portions of the scale, or the individual components were uncoupled, positioned completely 

on the live elements, and weighed separately on the scale.

[subsequent requirements to be renumbered as appropriate]

On May 19, 2022, OWM provided S&T Chair Bachelder an electronic file containing the following 

revised version of the B6: SCL-22.3 proposal as replacement for the current proposal in 2022 NCWM 

Publication 16. OWM requested he share it with the Committee to be considered as replacement for the 

current proposal in the Committee’s agenda.

OWM’s Revised Replacement Proposal for B6: SCL-22.3 UR.3.3. Single-Draft Vehicle Weighing, 

and UR.3.4. Axle and Axle Group Weight Values.

Amend NIST Handbook 44, Scales Code as follows:

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, the weight of:

(a) a coupled combination may be determined by uncoupling the various elements (tractor, 

semitrailer, trailer), weighing each unit separately as a single draft, and adding together the 

results; or

(b) a vehicle or coupled-vehicle combination may be determined by adding together the weights 

obtained while all individual elements are resting simultaneously on more than one scale 

platform.

Note: This paragraph does not apply to highway-law-enforcement scales, and scales used for the 

collection of statistical data, or scales used to charge a fee for the service of providing weights 

of the different axle-, axle-group loads, and total weight of vehicles and coupled-vehicle 

combinations when the only use of those values is to determine compliance with highway 

legal load limits and safe distribution of the load. 

(Added 1992)

UR.3.4. Weighing of Axle- and Axle-Group Loads – Establishing weight values for the 

different individual axle- and axle-group loads of a vehicle or coupled-vehicle combination is 

oftentimes necessary to verify compliance with state and federal highway load limits. When a 

fee is charged for the use of an axle-load scale or vehicle scale to determine such values, the 

transaction is considered “commercial” under the provisions of the General Code paragraph GA.1. Commercial and Law Enforcement Equipment and the scale shall comply with all 

applicable NIST Handbook 44 requirements for commercial weighing systems. 

When weight values for axle- and/or axle-group loads are obtained using multiple-independent 

platform vehicle scales systems where all parts of the vehicle or coupled-vehicle combination 
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being weighed are simultaneously positioned on live elements of the scale, the values for the 

different axle- and axle-group loads may be summed to establish the commercial gross weight. 

In no case, however, shall a summed result of the different axle- and axle-group loads of a 

vehicle or coupled vehicle combination weighed in multiple drafts be used for commercial 

purposes except as provided in subparts (a) and (b) of paragraph UR.3.3. Single-Draft Vehicle 

Weighing.

Renumber existing paragraphs UR.3.4 through UR.3.12.

During the 2023 NCWM Interim Meeting the Committee received several comments supporting the 

further development of this item. The Committee recommended the submitter work with interested 

parties to further develop SCL-22.3.

During the 2023 NCWM Annual Meeting, Jan Konijnenburg (NIST Office of Weights & Measures) 

requested the Committee update the item to reflect the most current language as included in the NIST 

OWM Executive Summary. The Committee agreed to update the item to reflect these changes.

Regional Association Reporting:

Central Weights and Measures Association

At CWMA’s 2023 Annual Meeting, NIST OWM submitted corrected language based on SMA concern 

about the term “legal” being confused with legal-for-trade. These are commercial devices, but they aren’t 

commercial weight values. These are for highway load requirements. Thomas Schuller (SMA) SMA 

supports this item. Konrad Crockford (North Dakota) had a similar situation in his state. Concern with 

charging of fees: presumption is that if a weight ticket / value is purchased from a commercial scale, it is 

considered a commercial value. Something needs to be added regarding signage saying weight value 

provided is not legal for trade.

The CWMA S&T Committee recommends this item remain as Developing.

Western Weights and Measures Association

The following comments were received during 2022 WWMA’s Interim Meeting on SCL-22.1 and SCL22.3, which at the time, were together in a Block (i.e., Block 6): 

Jan Konijnenburg (NIST Associate) stated that information is available on the website. 

During Open Hearings, the Committee received an update from NIST OWM indicating that new language 

for this proposal was submitted to NCWM. This language was not available for review at the time of 

open hearings by the committee or membership. The WWMA S&T Committee recommends that this 

item should remain developing to allow membership to review the updated proposal. 

At the 2023 WWMA Annual Meeting, Loren Minnich (NIST OWM) remarked that the SMA comments 

have been addressed and recommends this item is ready for a vote.

Cory Hainy (SMA) expressed the April 2023 analysis represents their position prior to the updates to the 

item and will reconvene in November 2023 to analyze the item. They support this item as developing 

status.
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Steve Harrington (Oregon) supported development of this item. He raised concerns that the device may 

potentially be used inappropriately to capture vehicle gross weight and recommends adding a user 

requirement of posting on a sign or recording on a scale ticket be added to the item to address this 

concern.

Kevin Schnepp (California) supports a voting status contingent on SMA analysis of the item.

The WWMA S&T Committee recommends that this item be assigned a Developing status to allow the 

submitter the opportunity to consider the comments heard on the floor and receive feedback from 

stakeholders.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, for Items SCL-22.1 and SCL-22.3, which at the time, were together 

in a Block (i.e., Block 6) Robert Huff (Delaware) questioned whether this would allow law enforcement 

officials to split weigh. 

The SWMA S&T Committee asked how legal split weighing would be initiated? How would it be 

recorded on the ticket? Would scale operators be required to mark the tickets where split weighing had 

taken place, or would that be automatically done? 

The SWMA S&T Committee recommends this item remain as a Developing item. 

At the 2023 SWMA Annual Meeting, Cory Hainy (SMA) stated their position is based on the April 

version of the item, but they have not had a chance to meet and review the changes to this item. They 

anticipate the SMA will be in favor of the item with the most recent changes.

The Committee feels the item is fully developed and recommends it move forward as a Voting item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Annual Meeting, Doug Bowland (SMA) supported the development of this item 

and has given feed back to the submitter.

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

a Developing status, and the body concurred.

At the 2023 NEWMA Interim Meeting, the State of New York supports as a developing item but cautions 

that the change to the Note would allow split weighing. The state of New Hampshire, Commonwealth of 

Massachusetts, and Pennsylvania concur. Upon the consensus of the body, the Committee recommends 

this item be Developing.

Scale Manufacturers Association Spring 2023 Meeting 

At the 2023 Spring Meeting SMA supported the further development of this item and submitted feedback 

to the submitter.

At the 2023 Fall Meeting the SMA noted that they do not support the language proposed to be added to 

the note in UR.3.3. as it would allow “the possibility of split weighing”.
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SCL-23.3 A Verification Scale Division e: Multiple Sections Including, T.N.1.3., Table 

6., T.N.3., T.N.4., T.N.6., T.N.8., T.N.9., T.1., T.2., S.1.1.1., T.N.1.2., Table 

S.6.3.a., Table S.3.6.b., Appendix D, S.1.2.2., Table 3., S.5.4., UR.3., Table 

8. 

Source: NCWM Verification Scale Division e Task Group

Submitter’s Purpose and Justification:

1. The mission of the task group, as defined by the S&T Committee, was to review Handbook 44, 

Section 2.20. Scales and relevant portions of OIML R76, using the items included in S&T 

Agenda Items: Block 2 as a reference point, and recommend changes as necessary to:

2. Clarify how the error is determined in relation to the verification scale division (e) and the scale 

division (d)

3. Clarify which is the proper reference; the verification scale division (e) or the scale division (d) 

throughout this section

4. Ensure proper selection of a scale in reference to the verification scale division (e) and the scale 

division (d)

5. Clarify the relationship between the verification scale division (e) or the scale division (d)

Background:

This proposal is being brought forward because the HB44 Scales Code is confusing and contradictory in 

several respects. This is particularly related to e and d and this has been true since the code was created as 

a translation of OIML R76 into HB44 format and adopted in 1984. In the creation process, the translators 

made a few translation errors that changed meanings or simply left important things out. Even small 

changes can have significant effects. We have been struggling with the contradictions ever since. In some 

cases, we continue to apply the code in ways that do not follow the written text. 

The original submitter (Ross Andersen, NY retired) compared each paragraph referring to d or e in HB44 

to the corresponding sections of R76 and identified a number of translation errors that either changed the 

meaning or left out something important from R76. He also proposed fixes. The Task Group continued 

the work and has prepared this final proposal. The sheer number of changes makes the proposal appear 

complicated. The changes all flow from the initial translation errors. The Task Group believes the 

changes are absolutely necessary, and the changes will eliminate the known conflicts and contradictions 

in the Code. This will subsequently reduce confusion in enforcing it.

Proposed changes to Appendix D. Definitions are presented first. The proposed changes and additions to 

the Scales Code will be presented in order of appearance. For each change or group of changes there will 

be a brief justification. The translators made key errors in the translation of two paragraphs dealing with 

basic principles. The repair of each of these paragraphs has ripple effects requiring corresponding changes 

in multiple related paragraphs throughout the code.
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NIST OWM Executive Summary for SCL-23.3 – Verification Scale Division e: Multiple Sections 

Including, T.N.1.3., Table 6., T.N.3., T.N.4., T.N.6., T.N.8., T.N.9., T.1., T.2., S.1.1.1., T.N.1.2., Table 

S.6.3.a., Table S.3.6.b., Appendix D, S.1.2.2., Table 3., S.5.4., UR.3., Table 8. 

NIST OWM Recommendation: Voting

• NIST OWM is of the opinion that the proposal is fully developed and supports a Voting status 

for this group of items. NIST OWM would like to stress the importance of this item. The 

current scale code in Handbook 44 contains several contradictions and inconsistencies with 

respect to the use of the terms “scale division”, and “verification scale division”. This leads to 

confusion and non-uniformity in the application of the code.

• The proposal presented by the task group is meant to clean up the code and bring clarification of 

the requirements with respect to e and d.

Table 2. Summary of Recommendations

SCL-23.3 Verification Scale Division e: Multiple Sections Including, T.N.1.3., Table 6., T.N.3., T.N.4., 

T.N.6., T.N.8., T.N.9., T.1., T.2., S.1.1.1., T.N.1.2., Table S.6.3.a., Table S.3.6.b., Appendix D, S.1.2.2., 

Table 3., S.5.4., UR.3., Table 8.

Status Recommendation Note* Comments

Submitter Voting

OWM Voting

WWMA Informational

NEWMA Voting

SWMA Assigned

CWMA Assigned

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered
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Item Under Consideration:

Amend Handbook 44 Scales Code as follows: 

Changes proposed to Appendix D. Definitions

auxiliary indication – a means to increase the displayed resolution of a weighing device, such as a 

rider or vernier on an analog device, or a differentiated least significant digit to the right of the 

decimal point on a digital device. [2.20]

(Added 20XX)

extended display mode. – a means to temporarily change the scale division (d) to a value less than 

the verification scale interval (e), following a manual command. [2.20]

(Added 20XX)

nmax (maximum number of verification scale intervals). – The maximum number of verification 

scale intervals for which a main element or load cell complies with the applicable requirements. 

The maximum number of verification scale intervals permitted for an installation is limited to the 

lowest nmax marked on the scale indicating element, weighing element, or load cell. [2.20]

(Added 20XX)

nmax (maximum number of scale divisions). – The maximum number of scale divisions for which a 

main element or load cell complies with the applicable requirements. The maximum number of scale 

divisions permitted for an installation is limited to the lowest nmax marked on the scale indicating element, 

weighing element, or load cell. [2.20, 2.21, 2.24] 

(Added 1997) (Amended 20XX)

scale division, number of (n). – See “verification scale interval, number of (n).” Quotient of the capacity

divided by the value of the verification scale division. [2.20]

(Amended 20XX)

verification scale divisioninterval, value of (e). – A value, expressed in units of weight (mass) and 

specified by the manufacturer of a device, by which the tolerance values and the accuracy class applicable 

to the device are determined. The verification scale divisioninterval is applied to all scales, in particular 

to ungraduated devices since they have no graduations. The verification scale division (e) may be 

different from the displayed scale division (d) for certain other devices used for weight classifying 

or weighing in pre-determined amounts, and certain other Class I and II scales.[2.20]

(Amended 20XX)

verification scale interval, number of (n). – Quotient of the capacity divided by the value of the 

verification scale interval. [2.20]

nn = CCCCCCCCCCCCCCCC

ee

(Added 20XX)
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weight classifier. – A digital scale that rounds weight values up to the next scale division. These scales 

usually have a verification scale divisioninterval (e) that is smaller than the displayed scale division (d). 

[2.20] 

(Added 1987) (Amended 20XX)

Changes proposed to Section 2.20. Scales Code

S.1.1.1. Digital Indicating Elements.

(a) A digital zero indication shall represent a balance condition that is within ± 1⁄2 the value of the 

scale division d.

(b) After zero-setting (gross zero or net zero after a tare operation) the effect of zero deviation 

on the result of the weighing shall be not more than ± 0.25 e.

[Nonretroactive as of January 1, 20XX]

(b)(c)A digital indicating device shall either automatically maintain a “center-of-zero” condition 

to ± 1⁄4 scale division or less, or have an auxiliary or supplemental “center-of-zero” 

indicator that defines a zero-balance condition to ± 1⁄4 of a scale division or less. A 

“center-of-zero” indication may operate when zero is indicated for gross and/or net 

mode(s). A digital indicating device shall have a “center-of-zero” indicator that indicates a 

zero-balance condition when the deviation from zero is not more than ± 0.25 e. A “centerof-zero” indicator may operate when zero is indicated for gross and/or net mode(s). The 

“center-of-zero” indicator is not mandatory on a device equipped with an auxiliary 

indication or equipped with an enabled zero tracking mechanism that maintains a “centerof-zero” condition to ± 0.25 e.

[Nonretroactive as of January 1, 1993]

(c)(d) For electronic cash registers (ECRs) and point-of-sale systems (POS systems) the display of 

measurement units shall be a minimum of 9.5 mm (3/8 inch) in height.

[Nonretroactive as of January 1, 2021]

(Added 2019)

(Amended 1992, 2008, and 2019, and 20XX)

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” and the verification 

scale interval “e” expressed in a unit of weight shall be equal to: 

(a) 1, 2, or 5; or 

(b) a decimal multiple or submultiple of 1, 2, or 5; or 

Examples: scale divisions may be 10, 20, 50, 100; or 0.01, 0.02, 0.05; or 0.1, 0.2, 0.5, etc. 

(c) a binary submultiple of a specific unit of weight. 

Examples: scale divisions may be 1⁄2, 1⁄4, 1/8, 1/16, etc. 

[Nonretroactive as of January 1, 1986]

(Amended 20XX)
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S.1.2.1. Digital Indicating Scales, Units. – Except for postal scales, a digital-indicating scale shall 

indicate weight values using only a single unit of measure. Weight values shall be presented in a 

decimal format with the value of the scale division “d” expressed as 1, 2, or 5, or a decimal multiple 

or submultiple of 1, 2, or 5.

The requirement that the value of the scale division “d” be expressed only as 1, 2, or 5, or a decimal 

multiple or submultiple of only 1, 2, or 5 does not apply to net weight indications and recorded 

representations that are calculated from gross and tare weight indications where the scale division 

“d” of the gross weight is different from the scale division “d” of the tare weight(s) on multi-interval 

or multiple range scales. For example, a multiple range or multi-interval scale may indicate and 

record tare weights in a lower weighing range (WR) or weighing segment (WS), gross weights in the 

higher weighing range or weighing segment, and net weights

as follows:

55 kg Gross Weight (WR2 d = 5 kg) 10.05 lb Gross Weight (WS2 d = 0.05 lb)

– 4 kg Tare Weight (WR1 d = 2 kg) – 0.06 lb Tare Weight (WS1 d = 0.02 lb)

= 51 kg Net Weight (Mathematically Correct) = 9.99 lb Net Weight (Mathematically 

Correct)

[Nonretroactive as of January 1, 1989] 

(Added 1987) (Amended 2008 and 20XX)

S.1.2.2. Verification Scale Interval “e”. 

S.1.2.2.1. Class I and II Scales and Dynamic Monorail Scales. – If e ≠ d, the verification 

scale interval “e” shall be determined by the expression:

d < e < 10 d

If the displayed division (d) is less than the verification division (e), then the verification 

division shall less than or equal to 10 times the displayed division.

The value of e must satisfy the relationship, e = 10k of the unit of measure, where k is a 

positive or negative whole number or zero. This requirement does not apply to a Class I 

device with d < 1 mg where e = 1 mg. If e ≠ d, the value of “d” shall be a decimal 

submultiple of “e,” and the ratio shall not be more than 10:1. If e ≠ d, and both “e” and 

“d” are continuously displayed during normal operation, then “d” shall be 

differentiated from “e” by size, shape, color, etc. throughout the range of weights 

displayed as “d.”

(Added 1999)

Scales Equipped with an Auxiliary Indication. – Only a Class I or II scale or a dynamic 

monorail may be equipped with an auxiliary indication. The auxiliary indication may 

be either a rider or vernier on an analog device, or a scale division “d” to the right of 

the decimal point on a digital device that is differentiated, for example by size, shape, or 

color. 

A scale with an auxiliary indication shall not be equipped with an extended display 

mode. 
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The verification scale interval “e” on a scale equipped with an auxiliary indication shall 

be determined as follows:

(a) The value of “e” shall be greater than “d” and less than or equal to 10 “d” (d < e 

< 10 d), and 

(b) The value of “e” must satisfy the relationship, e = 10k of the unit of measure, 

where k is a positive or negative whole number or zero.

Examples: 

10−2=0.01, 10−1=0.1, 100=1, 101=10, 102=100, etc. 

The requirement in subpart (a) does not apply to a Class I devices with e = 1 mg, 

where d shall be less than “e” (d < e). 

Examples: 

If e = 1 g for Class I or II, then “d” may only be 0.5 g, 0.2 g, or 0.1 g

If e = 1 mg for Class I, then “d” may be 0.5 mg, 0.2 mg, 0.1 mg, 0.05 mg, 0.02 

mg, etc.

(Added 1999) (Amended 20XX)

S.1.2.2.2. Class III, III L, and IIII Scales. – The value of “e” is specified by the manufacturer 

as marked on the device. Except for dynamic monorail scales and weight classifiers, “e” must be 

less than or equal to “d.”

(Added 1999) (Amended 20XX)

S.1.2.2.2.1. Dynamic Monorail Scales. – On a dynamic monorail scale the value of “e” 

shall be equal to or greater than “d”.

S.1.2.2.2.2. Weight Classifiers. – On a weight classifier, such as a postal or shipping 

scale that rounds up and is marked for special use, the value of “e” shall be equal to or 

less than “d”.

(Added 20XX)

S.1.2.2.3. Extended Display Mode. – A scale with an auxiliary indication shall not be 

equipped with an extended display mode. When a scale is equipped with an extended 

display mode, displaying an indication with a scale division “d” smaller than “e” shall be 

possible only:

(a) while pressing a key; or

(b) for a period not exceeding 5 seconds after a manual command. 

Printing or transferring data via interface shall not be possible while the extended 

display mode is in operation.

(Added 20XX)
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(Amended 2021 and 20XX) 

--------------------------------------

S.5.4. Relationship of Minimum Load Cell Verification Interval Value to the Verification Scale 

DivisionInterval. – The relationship of the value for the minimum load cell verification scale interval, 

vmin, to the verification scale divisioninterval d e, for a specific scale using National Type Evaluation 

Program (NTEP) certified load cells shall comply with the following formulae where N is the number of 

load cells in a single independent1 weighing/load-receiving element (such as hopper, railroad track, or 

vehicle scale weighing/load-receiving elements):

(a) vmmmmmm ≤ dd∗ee

√NN ffffff ssssssssssss wwwwwwh oo ll ssssss ssssss; aaaa

(b) vmmmmmm ≤ dd∗ee

√NN× (ss ss mmmm ) ffffff ssssssssssss wwwwwwh ll ssssss ssss

1”Independent” means with a weighing/load-receiving element not attached to adjacent elements and with

its own A/D conversion circuitry and displayed weight.

[*When the value of the scale division, d, is different from the verification scale division, e, for the 

scale, the value of e must be used in the formulae above.]

This requirement does not apply to complete weighing/load-receiving elements or scales, which satisfy

all the following criteria:

- the complete weighing/load-receiving element or scale has been evaluated for compliance with

T.N.8.1. Temperature under the NTEP;

- the complete weighing/load-receiving element or scale has received an NTEP Certificate of

Conformance; and

- the complete weighing/load-receiving element or scale is equipped with an automatic zero-tracking

mechanism which cannot be made inoperative in the normal weighing mode. (A test mode which

permits the disabling of the automatic zero-tracking mechanism is permissible, provided the scale

cannot function normally while in this mode.

[Nonretroactive as of January 1, 1994]

(Added 1993) (Amended 1996, 2016 and 20XX)
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[Nonretroactive as of January 1, 1986]

(Amended 1986, 1987, 1997, 1998, 1999, 2003, and 2004, and 20XX)

Table 3.

Parameters for Accuracy Classes

Class Value of the Verification Scale 

DivisionInterval (d or e1

)

Number of Verification Scale43 

DivisionsIntervals (n)

Minimum Maximum

SI Units

I equal to or greater than 1 mg 50 000 --

II 1 to 50 mg, inclusive 100 100 000

equal to or greater than 100 mg 5 000 100 000

III21,54 0.1 to 2 g, inclusive 100 10 000

equal to or greater than 5 g 500 10 000

III L32 equal to or greater than 2 kg 2 000 10 000

IIII equal to or greater than 5 g 100 1 200

1

For Class I and II devices equipped with auxiliary reading means (i.e., a rider, a vernier, or a least 

significant decimal differentiated by size, shape, or color), the value of the verification scale division “e” is 

the value of the scale division immediately preceding the auxiliary means. 21 A Class III scale marked “For prescription weighing only” may have a verification scale divisioninterval (e) 

not less than 0.01 g.

(Added 1986) (Amended 2003)

32

The value of a verification scale divisioninterval (e) for crane and hopper (other than grain hopper) scales 

shall be not less than 0.2 kg (0.5 lb). The minimum number of verification scale divisionsintervals (n) shall be 

not less than 1000.

(Amended 20XX)

43 On a multiple range or multi-intervalscale, the number of divisionsfor each range independently shall not

exceed the maximum specified for the accuracy class. The number of verification scale

divisionsintervals, (n), for each weighing range is determined by dividing the scale capacity for each range 

by the verification scale divisioninterval, (e), for each range. On a scale system with multiple load-receiving

elements and multiple indications, each element considered shall not independently exceed the maximum

specified for the accuracy class. If the system has a summing indicator, the nmax for the summed indication 

shall not exceed the maximum specified for the accuracy class.

(Added 1997)(Amended 20XX)

54 The minimum number of verification scale divisionsintervals (n) for a Class III Hopper Scale used for weighing 

grain shall be 2000.)

(Amended 20XX)
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Table S.6.3.a.

Marking Requirements

NOTE: Many rows of the table are not included in this proposal for brevity.

Weighing Equipment 

To Be Marked With ⇓

Weighing, 

LoadReceiving, 

and 

Indicating 

Element in 

Same Housing 

or Covered on 

the Same CC1

Indicating 

Element not 

Permanently 

Attached to 

Weighing and 

LoadReceiving 

Element or 

Covered by a 

Separate CC

Weighing and 

LoadReceiving 

Element Not 

Permanently 

Attached to 

Indicating 

Element or 

Covered by a 

Separate CC

Load Cell 

with CC

(11)

Other 

Equipment 

or Device

(10)

Manufacturer’s ID (1) X X X X X

Model Designation and Prefix (1) X X X X X

Serial Number and Prefix (2) X X X X X (16)

Certificate of Conformance Number 

(CC) (23) X X X X X (23)

Accuracy Class (17) X X (8) X (19) X

Nominal Capacity (3)(18)(20) X X X

Value of Scale Division, “d” (3)(4) X X

Value of Verification Scale 

Interval, “e” (3)(4) X X

Temperature Limits (5) X X X X

Concentrated Load Capacity (CLC)

(12)(20)(22)

Special Application (13) X X X

Maximum Number of Verification

Scale DivisionsIntervals (nmax) (6) X (8) X (19) X

(Added 1990) (Amended 1992, 1999, 2000, 2001, 2002, and 2004, and 20XX)

Table S.6.3.b.

Notes for Table S.6.3.a. Marking Requirements

NOTE: Remainder of the table is omitted for brevity with this proposal.

3. The device shall be marked with the nominal capacity. The nominal capacity may be prefaced by the terms 

“capacity” or “Max.” For any scale where the value of “e” is equal to the value of “d” (see S.1.2.2.), Tthe

nominal capacity shall be shown together with the value of the scale division “d” or the verification scale 

interval “e” (e.g., 15 × 0.005 kg, 30 × 0.01 lb, or capacity = 15 kg, d = 0.005 kg, or Max 15 kg e = 0.005 kg) in 

a clear and conspicuous manner and be readily apparent when viewing the reading face of the scale indicator 

unless already apparent by the design of the device. On multiple range or multi-interval scales the value of 

theEach scale division value “d” or verification scale interval “e” or weight unit shall be marked together with 
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Table S.6.3.b.

Notes for Table S.6.3.a. Marking Requirements

NOTE: Remainder of the table is omitted for brevity with this proposal.

its associated nominal capacityon multiple range or multi-interval scales. For any scale that has no “d” or 

any scale where “e” does not equal “d” refer to Note 4.

[Nonretroactive as of January 1, 1983]

(Amended 2005 and 20XX)

4. Required only if different from “d.” Exceptions to Note 3 regarding marking of “e” and “d.”.

(a) For an ungraduated scale such as an equal arm scale where the scale graduations do not represent a 

fixed weight quantity, the nominal capacity shall be shown together with the verification scale interval 

“e” (e.g. capacity 1,000 g e = 0.1 g, or Max 1,000 g e = 01 g). These devices have no “d.”

(b) For a scale where e does not equal d, such as a scale equipped with an auxiliary indication or a weight 

classifier marked for special use, the nominal capacity shall be shown together with the scale division ”d” 

and the verification scale interval “e,” (e.g., capacity 1,000 g e = 0.1 g d = 0.01 g, or Max 1,000 g e = 0.1 g 

d = 0.01 g).

[Nonretroactive as of January 1, 1986]

(Amended 20XX)

5. Required only on Class III, III L, and IIII devices if the temperature range on the NTEP CC is narrower than

and within − 10 °C to 40 °C (14 °F to 104 °F). [Nonretroactive as of January 1, 1986]

(Amended 1999)

6. This value may be stated on load cells in units of 1000; e.g., n: 10 is 10 000 divisions. [Nonretroactive as of 

January 1, 1988]

7. Denotes compliance for single or multiple load cell applications. It is acceptable to use a load cell with the “S” 

or Single Cell designation in multiple load cell applications as long as all other parameters meet applicable 

requirements. A load cell with the “M” or Multiple Cell designation can be used only in multiple load cell 

applications.

[Nonretroactive as of January 1, 1988]

(Amended 1999)

8. An indicating element not permanently attached to a weighing element shall be clearly and permanently marked

with the accuracy Class of I, II, III, III L, or IIII, as appropriate, and the maximum number of verification 

scale divisionsintervals, nmax, 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 divisionsnmax for which the device complies with the applicable 

requirements for each accuracy class.

[Nonretroactive as of January 1, 1988]

(Amended 20XX)
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T.1. Tolerance Values.

T.1.1. General. – The tolerances applicable to devices not marked with an accuracy class shall have 

the tolerances applied as specified in Table T.1.1. Tolerances for Unmarked Scales.

Note: When Table T.1.1. refers to T.N. sections it shall be accepted that the scale division d on the 

unmarked scale always equals the verification scale interval e.

(Amended 1990 and 20XX)

T.2. Sensitivity Requirement (SR).

T.2.2. General. – Except for scales specified in paragraphs T.2.3. Prescription Scales through T.2.8. 

Railway Track Scales: 2 (e) d, 0.2 % of the scale capacity, or 40 lb, whichever is least.

(Amended 20XX)

T.2.4. Jewelers’ Scales.

T.2.4.2. With More Than One-Half Ounce Capacity. – 1 (e) d or 0.05 % of the scale 

capacity, whichever is less.

(Amended 20XX)

T.2.7. Vehicle, Axle-Load, Livestock, and Animal Scales.

T.2.7.1. Equipped With Balance Indicators. – 1 (e) d.

(Amended 20XX)

T.2.7.2. Not Equipped With Balance Indicators. – 2 (e) d or 0.2 % of the scale capacity, 

whichever is less.

(Amended 20XX)

T.2.8. Railway Track Scales. – 3 (e) d or 100 lb, whichever is less.

(Amended 20XX)

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 verification scale divisionsintervals (n) and the value of the verification scale 

divisioninterval (d)(e).

(Amended 20XX)

T.N.1.3. Verification Scale DivisionInterval. – The tolerance for a weighing device is related to 

the value of the scale division (d) or the value of the verification scale divisioninterval (e) and is 

generally expressed in terms of d or e. 

(Amended 20XX)
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T.N.3. Tolerance Values.

T.N.3.4. Crane and Hopper (Other than Grain Hopper) Scales. – The maintenance and 

acceptance tolerances shall be as specified in T.N.3.1. Maintenance Tolerance Values and T.N.3.2. 

Acceptance Tolerance Values for Class III L, except that the tolerance for crane and construction 

materials hopper scales shall not be less than 1 e d or 0.1 % of the scale capacity, whichever is less.

(Amended 1986 and 20XX)

Table 6.

Maintenance Tolerances

(All values in this table are in verification scale divisionsintervals (e))

Tolerance in Scale Divisions

1 2 3 5

Class Test Load Applied

I 0 - 50 000 50 001 - 200 000 200 001 +

II 0 - 5 000 5 001 - 20 000 20 001 +

III 0 - 500 501 - 2 000 2 001 - 4 000 4 001 +

IIII 0 - 50 51 - 200 201 - 400 401 +

III L 0 - 500 501 - 1 000 (Add 1 d e for each additional 500 d e or fraction 

thereof)

(Amended 20XX)

T.N.4. Agreement of Indications.

...

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 

verification scale divisioninterval (e) (d) and be within tolerance limits.

(Amended 1986 and 20XX)

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 de for scales equipped with balance indicator, and 2 de or 0.2 % of 

the scale capacity, whichever is less, for scales not equipped with balance indicators.

(b) For all other nonautomatic-indicating scales, the test load for sensitivity shall be 1 de at zero 

and 2 de at maximum test load.

(Amended 20XX)
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T.N.8. Influence Factors. 

...

T.N.8.1.3. Temperature Effect on Zero-Load Balance. – The zero-load indication shall not vary 

by more than:

(a) three divisionse per 5 °C (9 °F) change in temperature for Class III L devices; or

(b) one divisione per 5 °C (9 °F) change in temperature for all other devices.

(Amended 1990 and 20XX)

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 escale division (d); or the equipment shall:

(a) blank the indication; or

(b) provide an error message; or

(c) the indication shall be so completely unstable that it cannot be interpreted, or transmitted into 

memory or to a recording element, as a correct measurement value.

The tolerance in T.N.9. Radio Frequency Interference (RFI) and Other Electromagnetic Interference 

Susceptibility is to be applied independently of other tolerances. For example, if indications are at 

allowable basic tolerance error limits when the disturbance occurs, then it is acceptable for the indication 

to exceed the applicable basic tolerances during the disturbance. 

(Amended 1997 and 20XX)

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 Verification Scale 

DivisionInterval e

(d or e*)

Recommended Minimum Load in 

Verification Scale Interval e (d or e*)

I equal to or greater than 0.001 g 100

II 0.001 g to 0.05 g, inclusive 20

equal to or greater than 0.1 g 50

III All** 20*

III L All 50

IIII All 10

*For Class I and II devices equipped with auxiliary reading means (i.e., a rider, a vernier, or a least 

significant decimal differentiated by size, shape or color), the value of the verification scale division 

“e” is the value of the scale division immediately preceding the auxiliary means. For Class III 

and IIII devices the value of “e” is specified by the manufacturer as marked on the device; “e” must 
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be less than or equal to “d.”**A minimum load of 10 d5 e is recommended for a weight classifier marked 

in accordance with a statement identifying its use for special applications.

(Amended 1990 and 20XX)

Other Issues Discussed by the Task Group: 

1. Based on input from the Scale Manufacturers Association and discussion within the task group 

the decision was made to replace all references to the “verification scale division” with the term 

“verification scale interval”. The intent of this change is to clearly differentiate between the 

verification scale interval (e) and the scale division (d) 

2. For reference, the following specifications, tolerances, and user requirements are specific to the 

scale division (d). 

Code Section Applies to Justification

G-S.5.2.2.(c) d Rounding is a function of instrument operation not accuracy

G-S.5.2.2.(d) d Requires “d” to be an indicated zero and all digits to the left of “d” to be 

zero when d<1.

Requires “d” to be an indicated zero and all digits to the right of “d” to be 

zero when d>5.

S.1.1.1.(a) d Describes width of the zero division, also sets up the normal rounding halfup/half-down 

S.1.2.1 d Refers to rounded values of d.

S.1.7.(b) e This is a classification issue addressing maximum indication above capacity.

S.2.1.2. d They must be in terms of d since stability of zero setting applies to d.

S.2.1.3.(all) d These limit the window for action of AZT. They must be in terms of d since 

zero setting applies to d.

S.2.3. d Tare division must equal smallest increment displayed.

T.N.7. d Discrimination requires an instrument to discriminate to the displayed scale 

division (zone of uncertainty). This relates to the rounding of the smallest 

increment.

3. The following specifications, tolerances, and user requirements are specific to the verification 

scale interval (e). No changes are proposed for these sections. 

Code Section Applies to Justification

S.1.2.3. e This is a classification issue. It ensures accuracy of the piece counts. 

N.1.10. e Refers to test loads verifying piece count and must be e.

N.4.5. e Refers to tolerances in time dependence tests and must be e.

T.N.9. e This is a tolerance for reaction to a disturbance. 

UR.3.10. e As written, this is clearly e. (See item 4 as this may need additional study) 
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4. The Task Group also observed that method of referencing the scale division and verification scale 

interval is inconsistent throughout the Code. In some cases, the paragraph only uses the 

abbreviation d or e, in other cases the name is stated without the abbreviation and in other cases 

the name is included with the abbreviation d or e in quotes or parentheses. Because the proposal 

only considers sections that needed change, this issue is not addressed formally in the proposal. 

The Task Group believes the change to a consistent method could be made editorially by OWM. 

In 1984, an initiative was taken by the National Conference on Weights and Measures (NCWM) to 

harmonize the scale code in section 2.20, Scales, of the NIST Handbook 44 (NIST HB 44) with OIML R 

76, the international standard on non-automatic weighing instruments used in legal metrology 

applications. Although many aspects of OIML R 76 were adopted in NIST HB 44, the exact same 

wording was not incorporated directly which led to unintended deviations, including the application of 

“scale division” (d), and the “verification scale division” (e). Furthermore, the current text in NIST HB 

44 section 2.20 contains some inconsistencies and contradictions. This leads to confusion and creates

non-uniformity in application of NIST HB 44 to scales where the “scale division” (d) differs from the 

“verification scale division” (e).

To evaluate the proposal of the task group, it is important to understand the difference between the “scale 

division” (d) and the “verification scale division” (e) as they were intended to be implemented in the 

Scale Code of Handbook 44. These are the definitions of scale division and verification scale division:

scale division, value of (d). – The value of the scale division, expressed in units of mass, is the

smallest subdivision of the scale for analog indication or the difference between two

consecutively indicated or printed values for digital indication or printing.

In other words, d is the resolution of the indication of a weighing instrument (the displayed, printed, or 

recorded value).

verification scale division, value of (e). – A value, expressed in units of weight (mass) and

specified by the manufacturer of a device, by which the tolerance values and the accuracy class

applicable to the device are determined. The verification scale division is applied to all scales, in

particular to ungraduated devices since they have no graduations. ...

Note that the definition of e does not state anything about the resolution of the indication of the weighing 

instrument. The verification scale division is used to define the accuracy classes and the applicable 

tolerances. The value of e is therefore a measure for the accuracy of the instrument, regardless of the 

resolution of the indication.

All requirements related to tolerance values should refer to e, while all requirements related to the 

resolution of the indications should refer to d.

In order to avoid confusion in the field and create uniformity in the understanding of the terms “scale 

division” and “verification scale division”, it is important that the Scale Code is cleaned up.

The majority of these proposed amendments simply replace “d” with “e” in those specification 

requirements that deal with the accuracy classification of a scale and the requirements that specify 

tolerances. Some have been amended to clarify how “e” & “d” interact when they are not equal to each 

other, e.g., when “e” is less than “d”, as can be the case with weight classifiers, and when “d” is less than 

“e”, as is the case with some Class I & II devices. 
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One change of note, to Table 8 Recommended Minimum Load, has been proposed to provide uniformity 

when determining the minimum load applied to a scale. Table 8 now only references “e”. In those 

instances where “e is not equal to “d” the minimum recommended load, if determined using “d” would be 

different for scales that have the same value for “e”. This is illustrated in the following table:

Accuracy Class Value of “e” Value of “d” Recommended Min. 

Load in “e”*

Recommended Min. 

Load in “d”**

II 0.1 g 0.05 g 5 g 1 g

II 0.1 g 0.02 g 5 g 0.4 g

III*** 0.1 oz 1 oz 0.5 oz 10 oz

III*** 0.1 oz 0.5 oz 0.5 oz 5 oz

*Calculated based on proposed amendments to Table 8

**Calculated based on current Table 8 specified values

***Weight Classifier

NIST OWM participated in the Verification Scale Division Task Group and is of the opinion that after 

more than 3 years of intensive work, the proposal for the amendment of several sections in the Scale Code 

has been thoroughly vetted and is ready to be adopted.

More background information regarding e and d can be found on the website of NIST OWM under 

Weighing FAQs (https://www.nist.gov/pml/owm/weighing-faqs).

NIST OWM Detailed Technical Analysis: 

In 1984, an initiative was taken by NCWM to harmonize NIST Handbook 44, Scale Code 2.20. with with 

OIML R 76, the international standard on non-automatic weighing instruments used in legal metrology 

applications. Although many aspects of OIML R 76 were adopted in NIST HB 44, the exact same 

wording was not incorporated directly which led to unintended deviations, including the application of 

“scale division” (d), and the “verification scale division” (e). Furthermore, the current text in NIST HB 

44 section 2.20 contains some inconsistencies and contradictions. This leads to confusion and creates 

non-uniformity in application of NIST HB 44 to scales where the “scale division” (d) differs from the 

“verification scale division” (e).

To evaluate the proposal of the task group, it is important to understand the difference between the “scale 

division” (d) and the “verification scale division” (e) as they were intended to be implemented in the 

Scale Code of Handbook 44. These are the definitions of scale division and verification scale division:

scale division, value of (d). – The value of the scale division, expressed in units of mass, is the 

smallest subdivision of the scale for analog indication or the difference between two consecutively 

indicated or printed values for digital indication or printing.

In other words, d is the resolution of the indication of a weighing instrument (the displayed, printed, or 

recorded value).

verification scale division, value of (e). – A value, expressed in units of weight (mass) and specified 

by the manufacturer of a device, by which the tolerance values and the accuracy class applicable to 
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the device are determined. The verification scale division is applied to all scales, in particular to 

ungraduated devices since they have no graduations. ...

Note that the definition of e does not state anything about the resolution of the indication of the weighing 

instrument. The verification scale division is used to define the accuracy classes and the applicable 

tolerances. The value of e is therefore a measure for the accuracy of the instrument, regardless of the 

resolution of the indication.

All requirements related to tolerance values should refer to e, while all requirements related to the 

resolution of the indications should refer to d.

In order to avoid confusion in the field and create uniformity in the understanding of the terms “scale 

division” and “verification scale division”, it is important that the Scale Code is cleaned up.

The majority of these proposed amendments simply replace “d” with “e” in those specification 

requirements that deal with the accuracy classification of a scale and the requirements that specify 

tolerances. Some have been amended to clarify how “e” & “d” interact when they are not equal to each 

others, e.g., when “e” is less than “d”, as can be the case with weight classifiers, and when “d” is less than 

“e”, as is the case with some Class I & II devices. 

One change of note, to Table 8 Recommended Minimum Load, has been proposed to provide uniformity 

when determining the minimum load applied to a scale. Table 8 now only references “e”. In those 

instances where “e is not equal to “d” the minimum recommended load, if determined using “d” would be 

different for scales that have the same value for “e”. This is illustrated in the following table:

Accuracy Class Value of “e” Value of “d” Recommended Min. 

Load in “e”*

Recommended Min. 

Load in “d”**

II 0.1 g 0.05 g 5 g 1 g

II 0.1 g 0.02 g 5 g 0.4 g

III*** 0.1 oz 1 oz 0.5 oz 10 oz

III*** 0.1 oz 0.5 oz 0.5 oz 5 oz

*Calculated based on proposed amendments to Table 8

**Calculated based on current Table 8 specified values

***Weight Classifier

NIST OWM participated in the Verification Scale Division Task Group and is of the opinion that after 

more than 3 years of intensive work, the proposal for the amendment of several sections in the Scale Code 

has been thoroughly vetted and is ready to be adopted.

Additional background information regarding e and d can be found at 

https://www.nist.gov/pml/owm/weighing-faqs under Weighing FAQs.

Summary of Discussion and Actions:

During the 2022 NCWM Interim Meeting, Richard Harshman (NIST OWM) commented that the items in 

this block represent very significant changes to the Scales Code of NIST HB 44 in that they are an 
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attempt to clarify which value, the value of the scale division (d), or verification scale division (e), are the 

paragraph requirements to be based. It is important that everyone agree; however, but this has not yet 

been the case. Richard Harshman noted that OWM disagreed with several of the changes proposed by the 

different items in this block as shown in the Committee’s current agenda. Richard Harshman also 

reported that the various Block 2 items in the Committee’s current agenda fail to reflect changes agreed to 

by members of the NCWM’s Verification Scale Division (e) Task Group (TG) as indicated in its second 

report to the Committee. That is, the proposals hadn’t been updated following the TG’s submission of its 

second report to the Committee. There seemed to be a misunderstanding between the TG and Committee 

on who would perform this work and it never got done. OWM looked forward to reviewing the proposals 

once this updating had been completed. 

Doug Musick (Kansas and Chair, Verification Scale Division (e) TG) acknowledged the accuracy of 

Richard Harshman’s reporting of the misunderstanding between the TG and Committee. He then 

requested the Committee either reassign the Block 2 items to the TG, or, if the Committee preferred, the 

Committee could perform the updating itself based on the TG’s most recent report. TG Chair. Musick 

also noted that the TG’s second report was included in Appendix A of the Committee’s 2022 Interim 

Agenda (NCWM Publication 15). 

Russ Vires (Mettler Toledo, LLC and speaking on behalf of the SMA) stated that the SMA supports the 

further development of this item and the work of the Verification Scale Division (e) TG. The SMA 

would also like to encourage the use of the terminology “Verification Interval” for “e” and “Scale 

Division” for “d” in every instance that it appears in this item.

The Committee also received several comments in support of reassigning the block of items to the TG for 

further revision. 

The Committee, in consideration of the comments received, agreed to reassign the block of items to the 

Verification Scale Division (e) TG for additional updating.

Prior to the 2023 NCWM Interim Meeting, the NCWM, in consultation with the chairperson of the 

NCWM Verification Scale Division (e) Task Group agreed to consolidate all of the Block 2 items that 

were on the committee’s 2022 agenda into a single item titled “SCL-23.3 – Verification Scale Division e: 

Multiple Sections Including, T.N.1.3., Table 6., T.N.3., T.N.4., T.N.6., T.N.8., T.N.9., T.1., T.2., S.1.1.1., 

T.N.1.2., Table S.6.3.a., Table S.3.6.b., Appendix D, S.1.2.2., Table 3., S.5.4., UR.3., Table 8” The 

following represents a summary of the NCWM discussions and actions relative to the items in Block 2 

prior to them being consolidated: 

The Committee looks forward to further development from the task group to which this item is Assigned.

During the 2023 NCWM Annual Meeting, the S&T Committee Chair stressed that the Task Group is 

currently without a Chair and asked for volunteers to chair the Task Group. Nobody volunteered. Charlie 

Rutherford stated that they are in contact with somebody who would be willing to chair the Verification 

Scale Division Task Group but did not disclose a name.
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Regional Association Reporting:

Western Weights and Measures Association

At the WWMA 2022 Annual Meeting Open Hearings, due to timing constraints, the Committee did not 

take comments on assigned items. The Committee did allow the source to provide updates on these 

items. No update was provided to the Committee.

The WWMA S&T Committee recommends that this item remain assigned and looks forward to a future 

update.

At the 2023 WWMA Annual Meeting, Loren Minnich (NIST OWM) stated the NCWM Verification 

Scale Division e Task Group now has a Chair and has met to begin cleaning up the language in the item. 

The task group will make changes to Table 8 so that it only references “verification scale division” (e). 

Requests this item be assigned an Informational status to receive feedback from the body of the NCWM.

Cory Hainy (SMA) supports further development of this item with the consideration all references to 

“verification scale division” be changed to “verification interval”. The SMA will reconvene in November 

2023 and requested this item to continue further development.

Kevin Schnepp (California) echoed SMA with the request this item be assigned an Informational status.

The WWMA 2023 S&T Committee recommends this item be assigned an Informational status to allow 

the body of NCWM to provide feedback.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, there were no comments received on this item. The SWMA S&T 

Committee recommends this item remain as an Assigned Item.

At the 2023 SWMA Annual Meeting, the Committee heard no comments. The Committee recommends 

this item remain an Assigned Item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Annual Meeting, Loren Minnich (NIST OWM) indicated support for the continued 

development of this item. Lou Sakin (Hopkinton, Massachusetts and Chair of the Cannabis Scales FG) 

stated that this will be critical for SCL-22.2 due to lack of current clarity and urged that this TG take 

action forthwith. Doug Bowland (SMA) stated support for further development and encourages the task 

group to make final changes or remove it from consideration. Loren Minnich also requested that in each 

instance in the item under consideration that “verification interval” be used for e and “scale division” for 

d.

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

a Assigned status. The Committee also noted that this Task Group has been without a Chair and 

encourages the NCWM Chair to appoint a new chair to continue the work of the group. The body 

concurred with the Committee.

At the 2023 NEWMA Interim Meeting, Steve Timar (New York and a member of the Scale Verification 

TG) stated the TG has met a few times and there has been much progress, including cleaning up some 
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definitions and other language. The TG has changed all references of “verification scale division” to 

“verification scale interval” throughout the item, as requested by SMA. A regulator from Holliston, 

Massachusetts recommended a voting. A regulator from New Hampshire stated the change to Table 6 in 

this proposal is different than New Hampshire’s new proposal. Upon consensus of the body, the 

Committee recommends this item be Voting. 

Central Weights and Measures Association

At the 2023 CWMA Annual Meeting, the SMA supported further development from TG and encourages 

TG to submit final changes or otherwise withdraw this item.

Thomas Schuller (SMA) stated the SMA supports the further development from the Verification Scale 

Division (e) Task Group. The SMA would encourage the workgroup to make the final changes and 

present it to the S&T Committee and Membership, otherwise remove it. The SMA encourages the use of 

the terminology “Verification Interval” for “e” and “Scale Division” for “d” in every instance that it 

appears in the Handbook.

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

remain Assigned.

Scale Manufacturers Association

At the 2022 FALL SMA Meeting (Block 2 items), the SMA supports the further development from the 

Verification Scale Division (e) Task Group. The SMA would encourage the workgroup to make the final 

changes and present it to the S&T Committee and Membership, otherwise remove it.

The SMA encourages the use of the terminology “Verification Interval” for “e” and “Scale Division” for 

“d” in every instance that it appears in the Handbook.

At the 2023 SMA Spring Meeting, they supported the further development from the Verification Scale 

Division (e) Task Group. The SMA would encourage the workgroup to make the final changes and 

present it to the S&T Committee and Membership, otherwise remove it.

The SMA encourages the use of the terminology “Verification Interval” for “e” and “Scale Division” for 

“d” in every instance that it appears in the Handbook.

SCL-24.3 Table 6. Maintenance Tolerances

(This item was introduced at the 2023 NEWMA Interim Meeting)

Source: New Hampshire Department of Agriculture, Markets, and Food

Submitter’s Purpose and Justification:

Provide clarity to NIST HB 44, 2.20. Scales, Table 6. Maintenance Tolerances. Table 6. will be easier to 

read if the vertical and horizontal grid lines are included, as seen in other tables within Handbook 44. The 

additional remarks added to Class III L will clarify the tolerance requirement for both regulators and other 

users of the handbook. Understanding Table 6. can be resolved through more thorough training.
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NIST OWM Executive Summary for SCL-24.3 – Table 6. Maintenance Tolerances

NIST OWM Recommendation: Informational

• OWM supports the effort to provide additional clarity to Table 6, specifically the interpretation 

of Class III L tolerances.

• Our office supports an Informational status until the weights & measures community agrees 

which of the proposed versions of Table 6 accomplishes that goal. 

Table 2. Summary of Recommendations

SCL-24.3 – Table 6. Maintenance Tolerances

Status Recommendation Note* Comments

Submitter Voting

OWM Informational

WWMA 4

NEWMA Developing

SWMA 4

CWMA 4

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered
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Item Under Consideration:

OPTION 1

Table 6.

Maintenance Tolerances

(All values in this table are in scale divisions)

Tolerance in Scale Divisions

Class

1 2 3 5

Test Load

I 0 - 50 000 50 001 - 200 000 200 001 +

II 0 - 5 000 5 001 - 20 000 20 001 +

III 0 - 500 501 - 2 000 2 001 - 4 000 4 001 +

IIII 0 - 50 51 - 200 201 - 400 401 +

III L 0 - 500 501 - 1 000 (Add 1 d for each additional 500 d or fraction thereof)

(Only applies to Class III L)

Or

OPTION 2

Table 6.

Maintenance Tolerances

(All values in this table are in scale divisions)

Tolerance in Scale Divisions

Class

1 2 3 5

Test Load

I 0 - 50 000 50 001 - 200 000 200 001 +

II 0 - 5 000 5 001 - 20 000 20 001 +

III 0 - 500 501 - 2 000 2 001 - 4 000 4 001 +

IIII 0 - 50 51 - 200 201 - 400 401 +

III L Determine Class III L tolerance by adding (add 1 d for each additional 500 d or fraction thereof

(0 – 500 = 1 d, 501 – 1000 = 2 d, 1001 – 1500 = 3 d, 1501 – 2000 = 4 d, etc.) 

Regional Association Reporting:

Western Weights and Measures Association

Southern Weights and Measures Association

Northeastern Weights and Measures Association

A presentation was provided by a regulator from the State of New Hampshire. The basis for the changes 

is to modify the appearance of table to be easier to read by adding horizontal and vertical lines and to add 
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clarification for Class IIIL scales. Two options for modification of the table have been provided. The 

regulator believes this could be a simple editorial change. The State of New York and Commonwealth of 

Pennsylvania believe the proposed modifications add value and clarity. Upon consensus of the body, the 

Committee recommends a Developing status, with both options presented to the membership for further 

discussion.

Central Weights and Measures Association

SCL-22.2 A UR.1. Selection Requirements, UR.1.X. Cannabis

Source: NCWM Cannabis Task Group

Submitter’s Purpose and Justification:

Establish uniform scale suitability requirements among the states for sales of cannabis.

NIST OWM Executive Summary for SCL-22.2 – UR.1. Selection Requirements, UR.1.X. Cannabis

1

NIST OWM Recommendation: Assigned

• The proposed amendments to Table 7a are ambiguous. The weighing of all cannabis products 

is assigned to accuracy classes I, II and III. This will lead to confusion in the field. For this 

reason, OWM recommends this item remains assigned to the Task Group. OWM offers to 

assist the Cannabis Task Group in developing a more appropriate proposal for the amendment 

of Table 7a.

____________________

1 In contrast to hemp, marijuana remains a Schedule I substance under the Controlled Substances Act. NIST does 

not have a policy role related to the legalization of the production, sale, distribution, or use of cannabis (including 

hemp and marijuana). NIST participates in the National Conference of Weights and Measures (NCWM) as part 

of NIST’s statutory mission to promote uniformity in state laws, regulations, and testing procedures.

Table 3. Summary of Recommendations

SCL-22.2 – UR.1. Selection Requirements, UR.1.X. Cannabis

Status Recommendation Note* Comments

Submitter

OWM Assigned

WWMA Assigned

NEWMA Assigned

SWMA Assigned

CWMA Assigned

NCWM

Number of 

Support 

Letters

Number of 

Opposition 

Letters

Comments
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Industry

Manufacturers 1 A&D

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

Regulatory 1 Florida Dept. of Ag & Consumer Services

*Notes Key:

1 - Submitted modified language

2 - Item not discussed

3 - No meeting held

4 - Not submitted on agenda

5 - No recommendation or not considered

Item Under Consideration:

Amend NIST Handbook 44, Scales Code as follows:

UR.1.1. General.

(a) For devices marked with a class designation, the typical class or type of device for particular 

weighing applications is shown in Table 7a. Typical Class or Type of Device for Weighing 

Applications.

(b) For devices not marked with a class designation, Table 7b. Applicable to Devices not Marked 

with a Class Designation applies.

Table 7a. Typical Class or Type of Device for Weighing Applications

Class Weighing Application or Scale Type

I Precision laboratory weighing and weighing of all Cannabis products

II Laboratory weighing, precious metals and gem weighing, grain test scales, and weighing of all 

Cannabis products

III

All commercial weighing not otherwise specified, grain test scales, retail precious metals and semiprecious gem weighing, grain-hopper scales, animal scales, postal scales, vehicle on-board weighing 

systems with a capacity less than or equal to 30 000 lb, and scales used to determine laundry 

charges, and weighing of all Cannabis products

III L

Vehicle scales (including weigh-in-motion vehicle scales), vehicle on-board weighing systems with 

a capacity greater than 30 000 lb, axle-load scales, livestock scales, railway track scales, crane 

scales, and hopper (other than grain hopper) scales

IIII Wheel-load weighers and portable axle-load weighers used for highway weight enforcement

Notes:

A scale with a higher accuracy class than that specified as “typical” may be used.

The use of italicized text in the references to “Cannabis” in this table is only to denote its proper taxonomic 

term; the italicized font does not designate a “nonretroactive” status as is the convention used throughout 
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NIST Handbook 44.

(Amended 1985, 1986, 1987, 1988, 1992, 1995, 2012, and 2021, and 20XX)

UR.3.1.2. Required Minimum Loads for Cannabis products. – The recommended minimum 

loads specified in Table 8 shall be considered required minimum loads for scales used to weigh

Cannabis and Cannabis-containing products.

[Nonretroactive as of January 1, 20XX]

(Added 20XX)

NIST OWM Detailed Technical Analysis: 

No longer are maximum scale division values proposed for the weighing of cannabis products as was the 

case with the original proposal. Consequently, no longer do the comments and recommendations that 

OWM developed previously for this item apply. 

The following represents OWM’s Executive Summary for the current proposal and provides justification 

for the “Assigned” status recommendation:

• Although OWM doesn’t believe it was the intent of the Cannabis TG - Scales Focus Group (a 

subgroup of the Cannabis TG), adding the terminology, “and weighing of all Cannabis products,” 

to each of the three accuracy class classifications in Table 7a (i.e., Class I, Class II, and Class III) 

leads one to believe that a scale of any one of those three accuracy classes would be permissible 

for use to weigh all cannabis products. 

A certain application or category of products should be assigned to only one accuracy class in 

Table 7a. If the assignment of classes I, II and III in the proposal are meant for different types of 

transactions, then this should be made clear in the designations in Table 7a, e.g., “retail sale of 

cannabis products” and “wholesale distribution of cannabis products”.

• It is OWM’s understanding that some participants of the Cannabis TG believe NIST HB 44 

requirements cannot be applied to scales used commercially to weigh cannabis products unless 

Table 7a explicitly indicates such use. We do not share this opinion and note that the description 

in Table 7a for Class III scales specifies “All commercial weighing not otherwise specified...,” 

which would include scales used to weigh cannabis products. That is, the description of 

“Weighing Application or Scale Type” in HB 44 Scales Code Table 7a for Class III scales 

adequately captures scales used to weigh cannabis products. 

• There are several commercial uses of scales excluded from Table 7a in which jurisdictions 

continually regulate those scales without concern. For example, scales used in a grocery store to 

weigh bakery items, meat products, delicatessen products, and produce are not explicitly 

identified in the existing table; yet these scales are regularly regulated by weights and measures 

officials throughout the US. The different uses of these scales are encompassed in the 

terminology, “All commercial weighing not otherwise specified...” as would be the case for 

scales used to weigh cannabis products.

• We take no position, however, on adding an additional example device type to HB 44 Scales 

Code Table 7a if others believe it is essential, since the title of the table specifies that the different 

device types listed are only “typical.” Yet, because the “Note” included at the bottom of Table 7a 

specifies a scale with a higher accuracy class than that specified as “typical” may be used, it is 
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unnecessary to add the additional device type to more than one accuracy class classification in the 

table. Adding it to the Class III description alone would suffice given that Class I and Class II 

scales are of higher accuracy class. Additionally, we believe adding the additional device type 

description to the Accuracy Class I and Class II classifications would cause unnecessary 

confusion due to the Note explaining that a higher accuracy class may be used. 

OWM believes that Class II scales are the most suitable device for retail sale of cannabis 

products, which would place cannabis in the same accuracy class as precious metals and gems. If 

the Cannabis TG is of the opinion that a class III is sufficient for wholesale transactions of 

cannabis products then this should clearly be designated in Table 7a, e.g., using the language 

“wholesale distribution of cannabis products”.

• OWM currently participates on the Scales Focus Subgroup of the NCWM Cannabis Task group. 

Most recently, several members of the subgroup have voiced support for the development of a 

scale suitability guidance document that could not only be used by the Cannabis industry, but 

other industries as well. We too would be in favor of developing such a document and believe it 

would be helpful in selecting a suitable scale.

Summary of Discussions and Actions:

During the 2022 NCWM Interim Meeting, the Committee received a somewhat widerange of comments 

during open hearings.

The Cannabis Scales Focus Group recognizes that, in addition to the proposed modifications of Table 7a, 

guidance is needed to assist businesses and inspectors in identifying suitable devices for use in various 

applications used to weigh Cannabis.

The Cannabis Scales Focus Group plans to continue discussions on the best method(s) for developing that 

guidance. This may include one or more of the following:

• Developing a guidance document to assist users, scale service companies, and inspectors in 

identifying appropriate scales for Cannabis weighing applications.

• Revisiting proposed modifications to paragraph UR.1. to either include:

o Proposing minimum requirements for Class II all weighing applications (non- product 

specific) as is already in place in some states; or

o Proposing minimum requirements for Class II weighing applications used specifically for 

Cannabis.)

In considering the comments received during open hearings, the Committee agreed to maintain the 

Assigned status of the item.

The NIST OWM Technical Advisors assigned to the S&T Committee opted to participate virtually in the 

2022 NCWM Annual Meeting due to COVID-19. During S&T open hearings, there was an audio 

problem with the virtual platform being used by the NCWM that prevented those participating virtually to 

hear much of the open hearing testimony. With regard to this particular item, no testimony could be 

heard by those attending virtually. A member of the national S&T Committee, who had attended the 

2022 NCWM Annual Meeting in person reported that the Committee was given an update from Charles 
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Rutherford (NCWM Cannabis Task Group Co-Chair). In his update, Co-Chair Rutherford requested that 

this item remain Assigned to the Task Group for further discussion. The Scales Focus Group will be 

regrouping, with Lou Sakin (Towns of Holliston, Hopkinton, Northbridge, Massachusetts) as the Chair, 

for further development of the item. The Committee agreed that this item will retain an Assigned status.

During the 2023 NCWM Annual Meeting, the Committee received a request for assigned status of the 

item from the co-Chair of the NCWM’s Cannabis Task Group (TG). The SMA noted in comments it 

provided that user requirements do not typically apply to a particular commodity. The SMA supported 

further development of the item and the additions to Table 7A. The Committee updated the item to 

include proposed new paragraph UR.3.1.2., as recommended by NEWMA and shown in the item under 

consideration of this report. The Committee also agreed to assign the item to the TG per 

recommendations from the submitters.

Regional Association Reporting:

Western Weights and Measures Association

During the 2021 Annual Meeting Open Hearings, Josh Nelson (Ex-Officio NCWM S&T Committee) put 

forward to address some issues for cannabis, recommend developing - still needs work and continue to 

work forward.

Matt Douglas (California Division of Measurement Standards) remarked that California supports further 

development, add non retroactive date - subsection A states up to capacity... lists suitability requirements 

based on California, however, this info is not a standard. 

Eric Golden (Cardinal Scales) remarked that in Section A, B, and C be better to say 0.1 g for net 

weighments up to 10 grams, then B 10 to 100 grams, then C say over 100, etc.

Kurt Floren (Los Angeles County, California) remarked that Eric Golden stated perfectly what is lacking. 

There has to be ranges put in as to where the graduations are appropriate.

Erin Sullivan (Colorado Department of Agriculture) asked if this pertain to cannabis in any form or 

concentration?

Josh Nelson asked if this is what is going into NIST HB44 - each jurisdiction has to define their own. For 

Oregon, medical is much different than retail. Retail has to abide by this and medical does not. Verbiage 

in A, B, and C does need additions.

Erin Sullivan is this grows vs. dispensaries? Different products in processing facilities are weighed with 

many containers on the scales. Do states determine the regulation?

Josh Nelson asked if it is up to the states to determine how to apply tares and increments in which product 

is weighed.

Kurt Floren (Los Angeles County, California): cannabis products: later we’ll see proposed def. of 

cannabis and cannabis products, are we anticipating the adoption of the proposed language?

Josh Nelson remarked it is not limited to flowers or bud. Mentions dabs. Is there a packaging 

requirement for the label? Oregon does. There must be a legal for trade scale that can prove they are 
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meeting net contents. They must ensure that their process is being executed correctly. He thinks this is 

not limited to flower/bud.

Kurt Floren this raises the point that further consideration needs to be put into terms. Brownies, cannabis 

infused pizza... and other items sold by weight. Are we setting the terms for pure cannabis product or are 

the scales being used for any cannabis containing product?

Josh Nelson welcomes written input for this topic from anyone. Don Onwiler was a big proponent in this; 

Josh Nelson will continue to develop this. 

Eric Golden asked for clarification on Josh Nelson: geared towards net sales, packaging for the customer. 

Is this part of the track and trace program for growers or just for retail?

Josh Nelson remarked this needs to be expanded upon, in Oregon. Even the growers have to do track and 

trace. Any scale weight that is used for the cannabis tracking system needs to be Weights and Measures 

compliant. Maybe has to address even a class III scale. They will look more into it. 

Joe Moreo (Agriculture Commissioner/Sealer) stated over time we are going to need one level for 

concentrates, one for food, one for flower, one size fits all will not work. 

Josh Nelson agrees that one size does not fit all. This will start to give limitations as to what a particular 

weight will be. Not trying to pigeonhole any device into one category, just trying to figure out what 

works, that’s the intent. 

The WWMA S&T Committee recommended the item be assigned a Developmental status so that the 

submitter could continue to work on this as they commented during open hearings. 

During the WWMA’s 2022 Annual Meeting, Cannabis Co-Chair Rutherford remarked that everything in 

this book isn't updated. They have added “and cannabis” to Table 7. cannabis talks about cannabis and 

hemp. They expect to finish soon. What is in the book is old and doesn’t apply any more. 

Due to timing constraints during Open Hearings, the Committee did not take comments on Assigned 

Items. The Committee did allow the source to provide updates on these items. An update from the CoChair Rutherford was provided. The WWMA S&T Committee recommends that this item remain 

Assigned. 

During the WWMA 2022 Annual Meeting, Co-Chair Rutherford stated that everything in this book isn't 

updated. They have added "and Cannabis" to Table 7. He also clarified that cannabis talks about 

cannabis and hemp. The Task Group expects to finish soon. He said that what is in the book is old and 

no longer applies.

During open hearings, due to timing constraints, the Committee did not take comments on assigned items. 

The Committee did allow the source to provide updates on these items. An update from the Co-Chair 

Rutherford was provided. The WWMA S&T Committee recommends that this item remain assigned.

At the 2023 WWMA Annual Meeting, NCWM Cannabis Task Group Co-Chair Wolpert stated this item 

is still being developed by the task group and requested the item remain assigned to the task group.

Kevin Schnepp (California) questioned basing the suitability of a scale on the type of product. 

Recommended this item remain assigned to the task group. Steve Harrington (Oregon) echoed California.
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Kurt Floren (Los Angeles County, California) referred to previous language of the item which stated 

weight ranges for the suitability of the device and the current language now references a product type. 

Recommended referring to the previous language of weight ranges. Commented Table 7a. is not 

enforceable and the item should remain assigned to the Task Group.

Cory Hainy (SMA) recommended a change of language in Table 7a. class III devices, replace the word 

“All Cannabis” with “non-retail Cannabis”. Recommend adding a comment in Table 7a. for reference to 

Table 8. for scale selection.

Wendy Hahn (Stanislaus County, California) echoed Kurt Floren with an additional concern that the table 

is confusing and someone may select a class of device that may not be suitable.

Aaron Yanker (Colorado Dept. of Agriculture Weights and Measures) supports this item with the 

proposed changes heard on the floor.

The WWMA 2023 S&T Committee recommends this item remain Assigned to the NCWM Cannabis 

Task Group and recommends the Task Group consider the comments heard during the open hearing.

Southern Weights and Measures Association

At the 2021 SWMA Annual Meeting, Russ Vires (SMA) stated that they have no position on this item at 

this time. 

Matt Curran (Florida) stated that he supports this as a Voting item. He also provided comments in 

support of this item from Eric Golden. Cardinal offered some changes as well. The suggested changes 

are as follows: 

UR.1.X. Cannabis. – The scale division for scales weighing Cannabis shall not exceed: 

(a) 0.01 g for net weighments up to capacity up to 10g, 

(b) 0.1 g for net weighments greater than 10g, up to 100g, capacity, and

(c) 1 g for net weighments greater than 100g, up to capacity. 

(Added 20XX) 

Charlie Rutherford stated that he supports this item moving forward as a Voting item with the changes 

suggested by Cardinal Scale and Matt Curran. 

This Committee recommended that this item be moved forward as a Voting item if the changes suggested 

above are made. 

During the 2022 SWMA’s Annual Meeting, Charlie Rutherford stated that Table 1A has been updated in 

the item. The SWMA S&T Committee recommended this item remain as an Assigned Item.

At the 2023 SWMA Annual Meeting, the Committee heard no comments on this item during Open 

Hearings.

The Committee recommends this item remain an Assigned item.
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Northeastern Weights and Measures Association

During the 2021 NEWMA Interim Meeting Open Hearings, Eric Golden made suggestions to change the 

language in this item to the following:

UR.1.X. Cannabis

(a) 0.01g for net weighments up to 10 g

(b) 0.1g for net weighments greater that 10g , up to 100 g, and

(c) 1 g for net weighments greater than 100g , up to capacity

Lou Sakin (Hopkinton/Northbridge, Massachusetts) commented that he agrees with changes above. 

Discussions were heard regarding the agreement with Table 8. in the scales code as this requirement is 

more restrictive than Table 8 parameters.

Eric Golden commented that national uniformity would be good and many states have informational 

publications that outline requirements in their state for Cannabis scale requirements. Jimmy Cassidy 

(Massachusetts) recommended Voting status with the changes above. Matt Curran (Florida) commented 

that harmonization with table 8 would be a good idea if possible. Lou Sakin questioned if Cannabis 

should be in italics. The Committee suggests making the change to italics for Cannabis. 

The NEWMA S&T Committee recommended that this item be given Voting status with suggested edits.

During the 2022 NEWMA Annual Meeting, James Cassidy (Massachusetts) commented as the Co-Chair 

of the NCWM Cannabis Task Group. He supported the Assigned status so the Task Group can continue 

to develop the item from comments received at the 2022 Interim. Russ Vires (SMA) supported continued 

development and indicated that a user requirement typically does not pertain to a specific commodity. 

Russ Vires suggested the words “retail cannabis” should be added to the “Class II” section of Table 7a 

and the words “bulk cannabis processing and sales” should be added to the “Class III” section of Table 

7a. 

Tina Butcher (NIST OWM) read the following statement: “As a non-regulatory metrology institute, 

NIST defers to federal agencies with regulatory authority under the Controlled Substances Act (CSA) for 

the scheduling of drugs or other substances. NIST does not have a policy role related to the production, 

sale, distribution, or use of cannabis (including hemp and marijuana). While the 2018 Farm Bill removed 

hemp from the list of controlled substances under Schedule 1 of the CSA, marijuana remains on that list. 

NIST must respect that distinction even as it exercises its statutory authority to develop and disseminate 

national weights and measures standards for the production, distribution, and sale of products in the 

commercial marketplace. NIST remains committed to providing technical assistance to the weights and 

measures community. OWM has provided key technical points for the community to consider in its 

deliberations of cannabis-related proposals, and OWM would be happy to provide any necessary 

clarification. OWM comments are intended to encourage technically sound application of legal 

metrology laws, regulations, and practices to the measurement and sale of these products.”

After hearing comments from the floor, the Committee recognized the need for further development of 

the item and recommended that the item retain an Assigned status. The Committee recommends the 

NCWM Cannabis Task Group work with the SMA and other stakeholders to further develop this item. 
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During the 2022 NEWMA Interim Meeting, the Committee recognized comments received the from 

Cannabis Task Group from the Chair Sakin (Cannabis TG Scales). Cannabis TG Co-Chair Rutherford 

commented that the Cannabis Scales Focus Group is under new leadership lead by Lou Sakin. Co-Chair 

Rutherford pointed out that the Item Under Consideration is not current and current language was sent to 

the NEWMA. Co-Chair Rutherford requested a Voting status for this item. Lou Sakin indicated that the 

new language was submitted to SWMA and NEWMA. The TG chose to modify tables instead of 

changing the entire code. He believes that the item is fully developed and ready for a Voting status. 

James Cassidy requested that this item move forward as Voting with changes as proposed in the 

submitted documentation. 

After hearing comments from the floor, the Committee agreed that the item has merit. The Committee 

agreed that the item, with recommended changes below, is ready for a Voting status.

Section 2.20. UR.3.1.2 Required Minimum Loads for Cannabis products. 

The recommended minimum loads specified in Table 8 shall be considered required minimum 

loads for scales used to weigh Cannabis and Cannabis-containing products. 

[Nonretroactive as of January 1, 20XX] 

And

Table 7a. Typical Class or Type of Device for Weighing Applications

Class Weighing Application or Scale Type

I Precision laboratory weighing and weighing of all Cannabis products

II Laboratory weighing, precious metals and gem weighing, grain test scales, and weighing of all 

Cannabis products 

III

All commercial weighing not otherwise specified, grain test scales, retail precious metals and semiprecious gem weighing, grain-hopper scales, animal scales, postal scales, vehicle on-board weighing 

systems with a capacity less than or equal to 30 000 lb, and scales used to determine laundry 

charges, and weighing of all Cannabis products 

III L

Vehicle scales (including weigh-in-motion vehicle scales, vehicle on-board weighing systems with a 

capacity greater than 30 000 lb, axle-load scales, livestock scales, railway track scales crane scales, 

and hopper (other than grain hopper) scales

IIII Wheel-load weighers and portable axle-load weighers used for highway weight enforcement

Notes: 

A scale with a higher accuracy class than that specified as “typical” may be used. 

The use of italicized text in the references to “Cannabis” in this table is only to denote its proper taxonomic 

term; the italicized font does not designate a “nonretroactive” status as is the convention used throughout 

NIST Handbook 44. 

(Amended 1985, 1986, 1987, 1988, 1992, 1995, 2012, and 2021)

At NEWMA’s 2023 Annual Meeting, Charlie Rutherford (CPR Squared) spoke as the Cannabis Task 

Group Co-Chair. They stated the team is sorting out d and e, which will inform group as how to move 

forward. Lou Sakin explained that the language in the handbook charts say “may” and gives an option of 

d or e. Hopes d and e task group would come up with more precise language. The Cannabis Task Group 

Scales Focus Group received input from other participants in NCWM with concern of adding language in 
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the tolerance chart that specifies the tolerances will apply to cannabis. The purpose was to follow form 

with precious metals and other items of high dollar value. Language in Table 8 says ‘may’ but may add 

language that says “shall” to apply to cannabis due to dollar value of the product in the marketplace. 

Doug Bowland (SMA) indicated support of development. Suggested that in Table 7a Class 3, replace 

wording with” non-retail cannabis” and refer to table 8 for cannabis selection. The exact SMA language 

changes were submitted in writing. Lou Sakin stated that as a field inspector, when scales are tested in a 

recreational facility, that is retail and should fall under the jurisdiction of this particular section. Some 

states require NTEP from seed to sale, which covers entire family of devices.

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

an Assigned status, and the body concurred.

During the 2023 NEWMA Interim Meeting, a regulator from Holliston, Massachusetts, and a Cannabis 

Task Group member recommended this item remain as assigned pending the Verification Scale Division 

Task Group item, as it impacts this item. Upon consensus of the body, the Committee recommends this 

item be Assigned. 

Central Weights and Measures Association

During the 2021 CWMA Interim Meeting Open Hearing, the Committee heard comments from the floor. 

Loren Minnich (Kansas) is not sure of the intent and that it needs more developing. Eric Golden agreed 

with is it “e” or “d”, will send notes to Committee. Ivan Hankins (Iowa) would support item with Eric 

Golden’s language. Eric Golden continued by recommending the following change to which will add 

clarity to the listed weight ranges in SCL-22.2 (in red): 

SCL-22.2 UR.1. Selection Requirements, UR.1.X. Cannabis 

UR.1.X. Cannabis. – The scale division verification scale interval, e, for scales weighing 

Cannabis shall not exceed:

(a) 0.01g for net weighments up to capacity up to 10g,

(b) 0.1g for net weighments greater than 10g, up to 100g, capacity, and 

(c) 1 g for net weighments greater than 100g, up to capacity.

(Added 20XX)

CWMA S&T Committee recommended as Voting Item with the proposed changes from Cardinal Scales.

During the 2022 CWMA Annual Meeting Open Hearings, Doug Musick (Kansas) welcomed the attempt 

to define suitability; recommended the following: 

SCL-22.2 UR.1. Selection Requirements, UR.1.X. Cannabis

UR.1.X. Cannabis. – A retail Cannabis scale shall not be used to weigh net loads smaller than 100 

displayed scale divisions “d”,

(a) 0.01g for net weighments 10g or less,

(b) 0.1g for net weighments greater than 10g and up to 100g, and
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(c) 1g for net weighments greater than 100g.

(Added 20XX)

Russ Vires (SMA) stated the addition of a User Requirement is not the best approach in this situation; 

User Requirements do not typically apply to a specific commodity. Supported continuing as Developing 

and the following proposed changes should be considered instead:

– The words “retail cannabis” should be added to the “Class II” section of Table 7a.

– The words “bulk cannabis processing and sales” should be added to the “Class III” section of 

Table 7a.

Charlie Stutesman (Kansas) questioned why only metric units are referenced and not also include inchpound units. The CWMA S&T Committee recommended this item remain with the NCWM Cannabis 

Task Group and that the suggested changes are considered.

During the 2022 CWMA Interim Meeting Open Hearings, Charlie Rutherford (ASTM International) 

remarked the old version is still listed in today’s agenda. Pushing the suitable scales discussion to a later 

date. The submitter provided updates to Table 7a. which add Cannabis verbiage to the weighing 

application column for Classes I, II, and III. 

The CWMA S&T Committee recommended this item remain Assigned with the NCWM Cannabis Task 

Group.

At the CWMA’s 2022 Annual Meeting, Co-Chair Rutherford stated this will be better developed once e 

vs. d is finalized. Hopefully the Task Group gets work done to submit updated language by Aug 15, 

2023. Thomas Schuller (SMA) stated the SMA supported this item.

The CWMA S&T Committee recommends this item remain as Assigned to the Task Group.

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

remain Assigned.

Scale Manufacturers Association (SMA)

During the 2021 SMA Fall and 2022 SMA Spring Meetings, the SMA supported the continued 

development of this item.

Rationale: The addition of a User Requirement is not the best approach in this situation; User 

Requirements do not typically apply to a specific commodity. The following proposed changes should be 

considered instead:

• The words “retail cannabis” should be added to the “Class II” section of Table 7a.

• The words “bulk cannabis processing and sales” should be added to the “Class III” section of 

Table 7a.

During the 2022 Fall SMA meeting, they supported the continued development of this item.
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Rationale: The addition of a User Requirement is not the best approach in this situation; User 

Requirements do not typically apply to a specific commodity. The following proposed changes should be 

considered instead:

• The words “retail cannabis” should be added to the “Class II” section of Table 7a.

• The words “bulk cannabis processing and sales” should be added to the “Class III” section of 

Table 7a.

During the SMA 2023 Spring Meeting, they supported the continued development of this item. The 

following was suggested:

• In Table 7a Class III, replace the word “All Cannabis” with “non-retail Cannabis”. 

• Add in notes section in Table 7a; “Refer to tale 8 for guidance on scale selection for Cannabis”.

AWS – Automatic Weighing Systems Code

AWS-24.1 N.1.5. Test Loads

Source: Marel Ltd.

Submitter’s Purpose and Justification:

Re-word AWS test loads section for clarity and consistency across rest of handbook.

Existing wording could be interpreted a number of different ways. This uncertainty bad for NTEP 

labs, W&M inspectors, and manufacturers. The original intention can be seen in HB 44 AWS N.2.2.2 

and in Publication 14, AWS 35.1.7 (copied below for convenience). I have spoken to NCWM staff 

and had it confirmed that the widely understood interpretation and understanding of note N.1.5. is as 

my replacement wording describes.

HB 44 AWS, N.2.2.2. Automatic Tests. - The device shall be tested at the normal operating speed 

using packages. Test runs should be conducted using at least two test loads distributed over its 

normal weighing range (e.g., near the lowest and highest ranges in which the device is typically 

operated.) Each test load should be run a minimum of ten consecutive times.

Pub 14 AWS, 35.1.7. Dynamic tests: The device shall be tested at the highest speed for each weight 

range using standardized test pucks or packages. Test runs shall be conducted using four test loads 

as described in Table N.3.2. Each test load shall be run a minimum of 10 consecutive times.

Checkweighers have similar requirements but must be run the number of times as described in N.4.2 

(copied below). All those numbers are 10 or greater so “minimum of 10 consecutive times” still 

works fine for checkweighers.
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Table N.4.2 Number of Sample Weights per Test for Automatic Checkweighers

Weighing Range m = mass of test load Number of Sample Weights per Test

20 divisions < m < 10 kg

20 divisions < m < 22 lb 60

10 kg < m < 25 kg

22 lb < m < 55 lb 32

25 kg < m < 100 kg

55 lb < m < 220 lb 20

100 kg (220 lb) < m 10

The submitter acknowledged the following potential arguments: The intention is for only four consecutive 

test runs per test loads. The openness of the wording allows laboratories and inspectors leeway to vary 

testing as they see fit for that application.

The submitter requested Voting status in 2024.

Executive Summary for AWS-24.1 – N.1.5. Test Loads

NIST OWM Recommendation: Voting, with recommended changes.

• OWM agrees with the submitter that the language in paragraph N.1.5. can be interpreted in 

different ways.

• Paragraph N.1.5. and Table N.1.5. Test Loads apply to all Automatic Weighing Systems which 

includes:

o Automatic weigh-labelers;

o Combination automatic and non-automatic weigh-labelers;

o Automatic checkweighers;

o Combination automatic and non-automatic checkweighers; and

o Automatic gravimetric filling machines that weigh discrete loads or single loads of loose 

materials and determine package and production lot compliance with net content 

representations.

• The subsequent paragraphs, N.2. & N.3. apply to Weigh-Labelers and Automatic 

Checkweighers, respectively.

• N.2. specifies how test loads are applied to Weigh-Labelers

• N.3. specifies how test loads are applied to Checkweighers.

• Because the application of test loads is specified in N.2. & N.3., OWM suggests amending 

N.1.5. as follows:
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Executive Summary for AWS-24.1 – N.1.5. Test Loads

N.1.5. Tests Loads. – A performance test shall consist of four separate test runsbe conducted 

atwith a minimum of four different test loads according to Table N.1.5. Test Loads.

• This would clarify what test loads are required and would retain the current requirements 

pertaining to the application of test loads.

Table 2. Summary of Recommendations

AWS-24.1 – N.1.5. Test Loads

Status Recommendation Note* Comments

Submitter Voting

OWM Voting 1

WWMA Developing

NEWMA 5

SWMA Developing

CWMA Developing

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44 Automatic Weighing Systems Code as follows:

N.1.5. Test loads. – A performance test shall consist of at least four separate test runs conducted at

different test loads according to Table N.1.5. Test Loads, each load being run a minimum of ten 

consecutive times.
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NIST OWM Detailed Technical Analysis: 

As written paragraph N.1.5 is unclear in what it requires. Does it mean a test should consist of each of the 

test loads specified in Table N.1.5. being applied four times or does it mean four separate tests should be 

conducted at the test loads specified in Table N.1.5.? Depending on how the paragraph is read it could be 

interpreted both ways.

Because the paragraph is addressing test loads OWM believes the intent was to specify the minimum 

number of different test loads required to conduct a proper test and was not intended to specify the 

number of “runs” for each test load. How test loads are applied to Weigh-Labelers and Checkweighers is 

specified in N.2. and N.3. respectively and both include requirements for devices that operate nonautomatically. For those devices there are no “test runs”, the test load is applied statically using test 

weights. Because N.2. & N.3. include tests that are conducted statically, specifying “test runs” in N.1.5. 

is incorrect.

For these reasons we support amending N.1.5. but not as originally proposed by the submitter. OWM 

believes the following amendments capture the intent of the paragraph and provides the clarity needed for 

uniform interpretation:

N.1.5. Tests Loads. – A performance test shall consist of four separate test runsbe conducted atwith a 

minimum of four different test loads according to Table N.1.5. Test Loads.

OWM contacted the submitter of the Item, Andrew Goddard, Marel Ltd, who supports these proposed 

changes to the item. With these changes OWM supports adoption of this item.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Developing and seeks input from industry stakeholders

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, a question was raised by the WWMA S&T Committee directed to 

the submitter if the intent of reference to the number of runs of test loads will introduce repeatability 

tolerances. The Committee did not receive a response during open hearings.

Steve Harrington (Oregon) supports this item for a Voting status. Cory Hainy (SMA) the association has 

not met on this item and intends to review it in the November 2023 SMA Meeting.

Aaron Yanker (Colorado Dept of Agriculture Weights and Measures) questioned the language of the 

types of tests, the definitions per the item, and the reference in Table N.4.2 referring only to the type 

evaluation and not the entire table. Recommended this item for Developing status.

Loren Minnich (NIST OWM) stated the current language as written in existing code is confusing and this 

item is an attempt to clarify that language.
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Kevin Schnepp (California) recommends this item be assigned a Developing status with pending review 

and position from the SMA.

The WWMA 2023 S&T Committee recommends this item be assigned a Developing status to allow the 

submitter the opportunity to receive input from stakeholders and address comments heard during open 

hearings. The Committee further recommends this item, AWS-24.2, and AWS-24.3 be Blocked.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Cory Hainy (SMA) stated they have not met to develop a position 

on this item.

The Committee believes this item has merit regarding clarifying the required number of tests with new 

language.

The Committee recommends this item move forward as a Developing item to allow additional feedback 

from other stakeholders.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, no comments were heard on this item and the Committee does 

not have a recommendation.

AWS-24.2 N.1.6. Influence Factor Testing.

Source: Marel Ltd.

Submitter’s Purpose and Justification:

Remove [influence factor testing conducted statically] section for clarity and consistency across rest of 

handbook.

It looks like HB44 was amended in 2004 to mandate automatic testing for automatic machines but this 

contradicting clause was accidentally left in? See HB 44 AWS N.2 Note, N.2.2.1, and Pub 14 AWS 36 

(copied below for convenience).

HB 44 AWS N.2

Note: If the device is designed for only automatic weighing, it shall only be tested in the automatic 

weighing mode.

(Amended 2004)

HB 44 AWS

N.2.2.1. Tests Non-Automatic. – If the automatic weighing system is designed to operate nonautomatically, and is used in that manner, during normal use operation, it shall be tested nonautomatically using mass standards. The device shall not be tested non-automatically if it is used only in 

the automatic mode.
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Pub 14 AWS 36

Influence factor testing shall be conducted:

• If the device is designed for use in static weighing, it shall be tested statically using mass 

standards.

• If the device is designed for only dynamic weighing, it shall only be tested dynamically.

• If the device is designed for static and dynamic weighing, it shall be tested statically and 

dynamically

The submitter acknowledged the following potential arguments: Influence factors should be tested 

statically (more repeatable results not dependent on vibrations, conveyor belt transfers, etc.) and the other 

sections, for example HB 44 AWS N.2. and Pub 14 AWS 36, should be changed or removed.

The submitter requested Voting status in 2024.

NIST OWM Executive Summary for AWS-24.2 – N.1.6. Influence Factor Testing 

NIST OWM Recommendation: Voting

• The effect of influence factors is evaluated under controlled conditions, typically only during 

NTEP evaluation.

• As identified by the submitter, NCWM Publication 14 has procedures for evaluating influence 

factors when testing AWS either statically or dynamically, depending on the system’s 

capabilities.

• A search of NIST Handbook 44 shows that only one other section, 5.58. Multiple Dimension 

Measuring Devices, has a note that mentions influence factors. Typically, NIST HB 44 

specifies tolerances associated with influence factors but does not specify a test (N. paragraph 

or test note).

• OWM agrees that this note is not needed and supports its removal.

Table 2. Summary of Recommendations

AWS-24.2 – N.1.6. Influence Factor Testing

Status Recommendation Note* Comments

Submitter Voting

OWM Voting

WWMA Developing

NEWMA 5

SWMA Developing

CWMA Developing
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NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44 Automatic Weighing Systems Code as follows:

N.1.6. Influence Factor Testing. – Influence factor testing shall be conducted statically.

NIST OWM Detailed Technical Analysis: 

The effect of influence factors must be evaluated under controlled conditions, typically in a laboratory 

setting, and there are tolerances associated with the effect of these factors on devices. Section 2.24. 

includes tolerances for influence factors and NCWM Publication 14 has extensive procedures for 

evaluating the effect of influence factors on the performance of a device. 

Only two sections in NIST Handbook 44 include the term “influence factor” in a note, 2.24. Automatic 

Weighing Systems and 5.58. Multiple Dimension Measuring Devices. In this instance the requirement 

that all influence factor testing be conducted statically is incorrect as not all AWS have the capability to 

operate in a static mode. OWM supports the removal and this note and supports a Voting status for this 

item.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Developing and seeks input from industry stakeholders.
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Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, Cory Hainy (Representing the SMA) stated the association has 

not met on this item and intends to review it in the November 2023 SMA meeting.

Kevin Schnepp (California Division of Measurement Standards): Recommends this item be assigned a 

Developing status with pending review and position from the SMA.

The WWMA 2023 S&T Committee recommends this item be assigned a Developing status to allow the 

submitter time to receive input from stakeholders. The Committee further recommends that these items, 

AWS-24.1, and AWS-24.3 be Blocked.

Southern Weights and Measures Association

At the SWMA 2023 Annual Meeting, Cory Hainy (SMA) stated they have not met to develop a position 

on this item.

The Committee feels that this item has merit. The Committee recommends this item move forward as a 

Developing item to allow for additional feedback regarding the use of static influence factor testing for 

automatic weighing systems.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, no comments were heard on this item and the Committee does 

not have a recommendation.

AWS-24.3 N.22.3. Shift Test (Dynamic)

Source: Marel Ltd.

Submitter’s Purpose and Justification:

Introduce dynamic shift test for automatic weigh labelers.

HB 44 currently only recognizes static shift tests but since automatic weighing systems that are designed 

to weigh only automatically should only be tested automatically, there should be a method to test the 

ability of an automatic only machine to cope with off-center loads.

Publication 14 AWS §35.1.8. (copied below for convenience) already describes an automatic/dynamic 

shift test that has been used many times and is clearly understood by laboratories, inspectors, and 

manufacturers. By copying this over to HB 44 and adapting the wording slightly, we can better align HB 

44 and Pub 14 and reduce confusion and misunderstandings.

Pub 14 AWS

35.1. Static Tests

35.1.1. Increasing-load test...
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35.1.2. Decreasing-load test...

35.1.3. Shift test...

35.1.4. Discrimination test...

35.1.5. Zero-load balance change...

35.1.6. Influence factor testing...

35.1.7. Dynamic tests: The device shall be tested at the highest speed for each weight range using 

standardized test pucks or packages. Test runs shall be conducted using four test loads as 

described in Table N.3.2. Each test load shall be run a minimum of 10 consecutive times.

35.1.8. Shift Test: To determine the effect of eccentric loading, for devices without a means to align 

packages, a test load equal to one-third (1/3) maximum capacity shall be passed over the load 

receiver or transport belt (1) halfway between the center and front edge, and (2) halfway 

between the center and back edge. 

(1)

(2)

The submitter acknowledged the following potential arguments: Testing shift dynamically is available for 

NTEP laboratories but is intentionally not made a requirement in Handbook 44. Dynamic shift testing is 

not expected to be carried out during field tests or subsequent evaluations.

The passage is fine but the name should be “Shift Test (Automatic)” as ‘automatic’ is frequently used in 

HB 44 where ‘dynamic’ is used in Pub 14.

The submitter requested Voting status in 2024.

NIST OWM Executive Summary for AWS-24.3 – N.22.3. Shift Test (Dynamic)

NIST OWM Recommendation: Voting

• NIST HB 44 currently has no shift test specified for devices that operate in the automatic mode 

only. Devices operating statically are tested for eccentricity with a test load equal to 1⁄2 

capacity. OIML R-51 specifies conducting this test at 1/3 capacity.

• Adoption of this item would align NIST Handbook 44 with OIML R-51, not only with the type 

of test but the test load required (1/3 capacity)

• Adding this will facilitate field testing of these devices to ensure accuracy when off center 

loading occurs.
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Table 2. Summary of Recommendations

AWS-24.3 – N.22.3. Shift Test (Dynamic)

Status Recommendation Note* Comments

Submitter Voting

OWM Voting

WWMA Developing

NEWMA 5

SWMA Developing

CWMA Developing

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44 Automatic Weighing Systems Code as follows:

N.2.2.3. Shift Test (Dynamic). - The device shall be tested at the normal operating speed. A test 

load equal to one-third (1/3) maximum capacity shall be passed over the load receiver or 

transport belt (1) halfway between the center and front edge a minimum of 10 consecutive 

times, and (2) halfway between the center and back edge a minimum of 10 consecutive times.

Note: The shift test is not applicable if the device has a means to align packages

NIST OWM Detailed Technical Analysis: 

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Developing and seeks input from industry stakeholders.
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Western Weights and Measures Association

At the 2023 WWMA Meeting, Cory Hainy (SMA) remarked association has not met on this item and 

intends to review it in the November 2023 SMA Meeting.

Kevin Schnepp (California) recommends this item be assigned a Developing status with pending review 

and position from the SMA.

Kurt Floren (Los Angeles County, California) recommends this item be assigned a Developing status. 

They raised a concern that the existing requirement for a shift test load is 50 % of the total scale capacity, 

they proceeded to question the reasoning behind the change in the shift test load to 1/3 of the total scale 

capacity.

The WWMA 2023 S&T Committee recommends this item be assigned a Developing status to allow the 

submitter to receive input from stakeholders. The Committee further recommends this item, AWS-24.1, 

and AWS-24.2 be Blocked.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Cory Hainy (SMA) stated they have not met to develop a position 

on this item.

The Committee feels a separate shift test may not be practical for routine field testing and suggests 

incorporating the shift test into the existing test procedure. The Committee recommends the item move 

forward as a Developing item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, no comments were heard on this item and the Committee does 

not have a recommendation.

WIM – Weigh-in-Motion Systems – Tentative Code

WIM-23.1 I Remove Tentative Status and Amend Numerous Sections Throughout

Source: New York City DOT, C2SMART, Kistler, and Maryland DOT

Submitter’s Purpose and Justification:

Provide a legal document that can be used by local and State agencies to certify Weigh-In-Motion (WIM) 

systems used for automated weight enforcement.

Introduction

The Brooklyn-Queens Expressway (BQE) is an aging and deteriorating 6-lane highway which comprises 

a critical link of I-278 - the sole Interstate highway in Brooklyn, connecting it to Manhattan, Staten 

Island, and Queens in New York. Constructed in 1954 and comprised of varying and complex structure 
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types, the segment of the BQE between Atlantic Ave. Interchange to the South and Sands St. to the North 

is nearing the end of its design life. Urgent repairs are underway, while roughly 110 spans may be in 

need of intervention by 2028, and another 75 spans may be in need of intervention within the next decade. 

Weigh in Motion (WIM) sensors, installed in October 2019, have revealed overweight vehicles, 

excessively exceeding FHWA legal load limits, with gross vehicle weights (GVW) that range from just 

over 80,000 lbs to as high as 200,000. The continued presence of overweight vehicles on the BQE 

contributes to the continued structural deterioration of this aging piece of infrastructure. The New York 

State legislature recently authorized the New York City Department of Transportation to conduct 

automated overweight vehicle enforcement through a WIM demonstration program; however, a universal 

standard has not yet been established that specifically defines a protocol for calibration and certification 

by the New York State local Division of Weights and Measures.

In response to this challenge, this proposal seeks an amendment of Section 2.25 of NIST Handbook 44 to 

allow for Weigh-In-Motion Systems Used for Automated Vehicle Weight Enforcement. The remainder 

of this proposal lays out the justification for the amendment, using the BQE as an example to establish the 

urgent need for the amendment, supported by data received from other State programs, including New 

Jersey, Maryland, and Indiana. The City of New York is not alone in its struggle to maintain the safety

and the structural integrity of its infrastructure. Guarding against violations of vehicle weight restrictions 

that are enacted to protect critical infrastructure is an issue of national concern.

The combined interstate data presented here stresses the national importance of establishing protocols for 

automated vehicle weight enforcement using WIM, citing:

• the deleterious effects of overweight vehicles and axles on primary structural components and 

pavements;

• the difficulty associated with the use of screening combined with stationary weighing stations to 

enforce vehicle weight regulations; 

• the percentages of overweight vehicles on major interstates across the nation; and the proven 

accuracy of WIM equipment used in several states across the nation.

The submitters requested that this be a Voting item in 2023.

NIST OWM Executive Summary for WIM-23.1 – Remove Tentative Status and Amend Numerous 

Sections Throughout

NIST OWM Recommendation: Informational 

• NIST OWM applauds the efforts of the submitter to address the concerns raised and 

incorporate the feedback received from the community into the item under consideration. Our 

office supports this most recent version of the item and is of the opinion that most major

concerns have been sufficiently addressed by the submitters.

• We agree that separating Section 2.25. which applies to WIM Systems used to screen and is a 

tentative code from this new proposed section, 2.26. which will apply to WIM Systems used to 

enforce highway load limits, is the best approach.

• The only concern we still have is the with paragraph N.1.3. Reference Scale, which allows the 

use of a single platform vehicle scale to weigh the axles or axle-groups of a reference vehicle 
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NIST OWM Executive Summary for WIM-23.1 – Remove Tentative Status and Amend Numerous 

Sections Throughout

which are then summed to determine the gross vehicle weight. Using a single platform vehicle 

scale to weigh axles or axle-groups in isolation, as N.1.3.2 requires, is impractical. It would 

seem this is only possible using an axle-load scale.

• Even if N.1.3. didn’t require the axles or axle-groups of a reference vehicle to be weighed in 

isolation, unless the approach for the scale is of sufficient length to ensure the reference vehicle 

is in the same plane as the vehicle scale while the reference values are being determined, there

is concern that the values determined would be inaccurate. 

• Because this version of the item wasn’t available for review by the regions in its entirety and 

due to the number of significant changes being proposed our office supports an Informational 

status to allow for further consideration.

Table 2. Summary of Recommendations

WIM-23.1 – Remove Tentative Status and Amend Numerous Sections Throughout

Status Recommendation Note* Comments

Submitter Voting

OWM Informational

WWMA Informational

NEWMA Voting

SWMA Informational

CWMA Voting

NCWM Informational

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry 2 Maryland DoT, C2SMART New York University, 

American Society of Civil Engineers, Rutgers (RIME)

Manufacturers 2 International Road Dynamics, Rekor

Retailers and 

Consumers

Trade Association 1 Scale Manufacturers Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered
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Item Under Consideration:

Amend Handbook 44 Weigh-In-Motions Systems Code as follows:

(NIST OWM has applied the appropriate formatting according to NIST Handbooks)

TABLE OF CONTENTS TO BE INSERTED WHEN ADOPTED INTO THE HANDBOOK

Section 2.26 Weigh-In-Motion Systems – Used for Vehicle Direct Enforcement 

A. Application

A.1. General . – This code applies to systems installed in a fixed location used to weigh vehicles, 

while in motion, for the purpose of direct enforcement of legal weight limits.

A.2. Exception. – This code does not apply to weighing systems intended for the collection of 

statistical traffic data and weighing systems used for vehicle enforcement screening.

A.3. Additional Code Requirements. – In addition to the requirements of this code, weigh-inmotion systems shall meet the requirements of Section 1.10. General Code.

S. Specifications

S.1. Design of Indicating and Recording Elements and of Recorded Representations.

S.1.1. Ready Indication. – The system shall provide a means of verifying that the system is 

operational and ready for use.

S.1.2. Value of System Division Units. – The value of a system division “d” expressed in a unit 

of weight shall be equal to:

(a) 1, 2, or 5; or

(b) a decimal multiple or submultiple of 1, 2, or 5.

Examples: divisions may be 10, 20, 50, 100; or 0.01, 0.02, 0.05; or 0.1, 0.2, 0.5, etc.

S.1.2.1. Units of Measure. – The system shall indicate weight values using only a single unit 

of measure. 

S.1.3. Maximum Value of Division. – The value of the system division “d” for a Class E weighin-motion (WIM) system (WIM) system shall not be greater than 200 kg or 500 lb.

S.1.3.1. Number of System Divisions. – The number of system divisions for Class E shall 

be a minimum of 50 and a maximum of 1,000.

S.1.3.2. Minimum Capacity. – The minimum capacity in system divisions for Class E shall 

be 10.

S.1.4. Value of Other Units of Measure.
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S.1.4.1. Speed. – Vehicle speeds shall be measured in miles per hour or kilometers per 

hour.

S.1.4.2. Axle-Spacing (Length). – The center-to-center distance between any two 

successive axles shall be measured in:

(a) meters and decimal submultiples of a meter;

(b) feet and inches; or

(c) feet and decimal submultiples of a foot.

S.1.4.3. Vehicle Length. – If the system is capable of measuring the overall length of the 

vehicle, the length of the vehicle shall be measured in feet and/or inches, or meters.

S.1.5. Capacity Indication. – An indicating or recording element shall not display nor record 

any values greater than 105 % of the specified capacity of the load receiving element.

S.1.6. Identification of a Fault. – Fault conditions affecting accuracy as specified in Table 

T.2.3. Maintenance Tolerances for Accuracy shall be presented to the operator in a clear and 

unambiguous means. No weight values shall be indicated or recorded when a fault condition is 

detected. The following fault conditions shall be identified:

(a) Vehicle speed is below the minimum or above the maximum system specified speed.

(b) The maximum number of vehicle axles as specified has been exceeded.

(c) A change in vehicle speed greater than that specified has been detected. 

(d) Imbalanced weight between the left and right wheels has exceeded the specified 

values.

(e) Vehicle has changed lanes between or in the proximity of the first and the last sensors.

(f) Any axle or wheel, or part of each is not on the load-receiving element of the sensors.

(g) Vehicle direction of travel is not valid for the installation.

S.1.7. Recorded Representations.

S.1.7.1. Values to be Recorded. – At a minimum, the following values shall be printed 

and/or stored electronically for each vehicle weighment:

(a) transaction identification number;

(b) station ID;

(c) lane identification (required if more than one lane at the site has the ability to 

weigh a vehicle in motion);

(d) vehicle speed;
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(e) number of axles;

(f) weight of each axle;

(g) identification and weight of axle groups;

(h) axle spacing;

(i) gross vehicle weight;

(j) total vehicle length;

(k) all fault conditions that occurred during the weighing of the vehicle, as identified in 

paragraph S.1.6. Identification of a Fault;

(l) violations, as identified in paragraph S.2.1. Violation Parameters, which occurred 

during the weighing of the vehicle; and

(m) time and date.

Note: Consult the specific jurisdictional legislation for additional values that may be required to 

issue enforcement violations. All gross vehicle, axle, and axle group weights must be printed and/or 

stored with the corrected values that include any necessary reductions due to the system tolerance 

and adopted violation thresholds. Violation thresholds may be dependent on additional items, not 

specified in this code.

S.1.8. Value of the Indicated and Recorded System Division. – The value of the system’s 

division “(d),” as recorded, shall be the same as the division value indicated.

S.2. System Design Requirements. 

S.2.1. Violation Parameters. – The instrument shall be capable of accepting user entered 

violation parameters for the following items:

(a) single axle weight limit;

(b) axle group weight limit;

(c) gross vehicle weight limit; and

(d) bridge formula maximum.

The instrument shall display and/or record violation conditions when these parameters have 

been exceeded.

Note: Jurisdiction-defined weight limits for S.2.1 Violation Parameters (a) through (d) can be 

used to determine the violation.

S.3. Design of Weighing Elements.
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S.3.1. Multiple Load-Receiving Elements. – An instrument with a single indicating or 

recording element, or a combination indicating-recording element, that is coupled to two or 

more load receiving elements with independent weighing systems, shall be provided with means 

to prohibit the 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.4. Design of Weighing Devices, Accuracy Class.

S.4.1. Designation of Accuracy. – WIM systems meeting the requirements of this code shall be 

designated as accuracy Class E. 

Note: This does not preclude higher accuracy classes from being proposed and added to this 

Code in the future when it can be demonstrated that weigh-in-motion systems grouped within 

those accuracy classes can achieve the higher level of accuracy specified for those devices.

S.5. Design of Balance 

S.5.2. Zero-Tracking Device. – A zero-tracking device shall have a range of 4% of the system 

capacity and operate only when: 

(a) the system is in a no-load condition;

(b) is in stable equilibrium; and

(c) the corrections are not more than 0.5 d per second; and

S.5.3. Totalizing Device. – A WIM system may be provided with a totalizing device for 

determining gross vehicle weight which operates: 

(a) automatically, in which case the instrument shall be provided with a vehicle 

recognition device defined in S.5.4. Vehicle Recognition/Presence Device; or

(b) semi-automatically (e.g., it operates automatically following a manual command). 

S.5.4. Vehicle Recognition/Presence Device. – WIM system which are able to operate without 

the intervention of an operator shall be provided with a vehicle recognition device. The device 

shall detect the presence of a vehicle in the weigh zone and shall detect when the whole vehicle 

has been weighed. WIM system shall not indicate or print the vehicle mass unless all wheel 

loads of the vehicle have been weighed. 

S.6. Accidental Breakdown and Maladjustment. – WIM system shall be so constructed that an 

accidental breakdown or maladjustment of control elements likely to disturb its correct functioning 

cannot take place without its effect being evident.

S.7. Marking Requirements. – In addition to the marking requirements in G S.1. Identification, 

the system shall be marked with the following information:

(a) accuracy class;
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(b) value of the system division “d”;

(c) operational temperature limits;

(d) number of instrumented lanes (not required if only one lane is instrumented);

(e) minimum and maximum vehicle speed;

(f) maximum number of axles per vehicle;

(g) maximum change in vehicle speed during weighment;

(h) minimum and maximum load; and

(i) any restrictions specified in the NTEP Certificate of Conformance.

S.7.1. Location of Marking Information. – The marking information required in Section 1.10. 

General Code, G S.1. Identification and S.7. Marking Requirements shall be visible after 

installation. The information shall be marked on the system or recalled from an information 

screen.

N. Notes

N.1. Test Procedures. 

N.1.1. Selection of Test Vehicles. – All dynamic testing associated with the procedures 

described in each of the subparagraphs of N.1.6 Test Procedures shall be performed with 

vehicles of these three types, at a minimum. 

(a) a two-axle, six-tire, single-unit truck or Federal Highway Administration (FHWA) 

Class 5; that is, a vehicle with two axles with the rear axle having dual wheels; 

(b) a three-axle, single-unit truck or FHWA Class 6; and 

(c) a five-axle, single-trailer truck or FHWA Class 9 (3S2 Type). 

(d) The gross vehicle weights shall be as stated in N.1.2.2. Dynamic Test Loads.

Note 1: Consideration should be made for testing the system using vehicles which are typical to the 

roadway in which the system is installed if different than the types listed in (a) through (c) above. 

Note 2: If the WIM system will be used to enforce the weight limit for vehicles with liquid loads, a 

vehicle with a liquid load shall be included in the selection of test vehicles. 

N.1.1.1. Weighing of Test Vehicles. – All test vehicles shall be weighed statically on a 

reference scale, meeting the requirements of Appendix A, before being used to conduct 

dynamic tests.

N.1.1.2. Determining Reference Weights for Axles, Axle Groups, and Gross Vehicle 

Weight. – The reference weights shall be the average weight value of a minimum of three 
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static weighments of all single axles, axle groups, and gross vehicle weight on a reference 

scale before being used to conduct the dynamic tests.

Note: The axles within an axle group are not considered single axles. 

N.1.2. Test Loads. 

N.1.2.1. Static Test Loads. – All static test loads shall use certified test weights.

N.1.2.2. Dynamic Test Loads. – Test vehicles used for dynamic testing shall be loaded as 

specified below. Except when testing for liquid loads, the “load” shall be non-shifting and 

shall be positioned to present as close as possible, an equal side-to-side load.

(a) a half load condition (60-80% of the legal load limit of the test vehicle) for a 

minimum of 10 runs per test vehicle type; 

(b) a full load condition (> 85% of the legal load limit for the test vehicle) for a 

minimum of 20 runs per test vehicle type; and

(c) When it is anticipated that a system will be used to enforce weight limits for 

vehicles that may be unloaded, e.g., an unloaded Class 9 vehicle crossing a bridge 

with a 20 TN maximum capacity, tests shall include unloaded vehicles as part of the 

test load. 

N.1.3. Reference Scale. – Each reference vehicle shall be weighed statically on a multiple 

platform vehicle scale or a single-platform vehicle scale.

The scale shall be tested prior to using it to establish reference test loads per direction from the 

jurisdiction and in no case more than 4 weeks prior. To qualify for use as a suitable reference 

scale, it must meet NIST Handbook 44, Class III L maintenance tolerances.

N.1.3.1. Multi-Platform Vehicle Scale. – It is comprised of three individual weighing/loadreceiving elements, each an independent scale. The three individual weighing/load receiving 

elements shall be of such dimension and spacing to facilitate: the single-draft weighing of all 

reference test vehicles; 

(a) the simultaneous weighing of each single axle and axle group of the reference test 

vehicles on different individual elements of the scale; and

(b) gross vehicle weight determined by summing the values of the different reference 

axle and reference axle groups of a test vehicle. 

N.1.3.2. Single-Platform Vehicle Scale. – Each individual axle or axle group of the 

reference test vehicles shall be measured on the single platform vehicle scale. Only one 

single axle or axle group for measurement shall be on the single platform, while other single 

axles or axle groups shall be off the platform. The gross vehicle weight shall be determined 

by summing all the single axles and axle groups.

N.1.3.3. Location of a Reference Scale. – The location of the reference scale must be 

considered since vehicle weights will change due to fuel consumption.
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N.1.4. Test Speeds. – All dynamic tests shall be conducted at two designated speeds.

(a) at a high speed – posted speed limit (Vmax); and

(b) at a low speed – site-specific minimum speed, not below manufacturer’s requirement 

(Vmin).

N.1.5. Reference Axle Spacings. – To establish reference axle spacing, before measuring the 

axle spacing, the test vehicle shall be positioned straight, and the driving axle shall also be 

straight. A steel tape measure shall be used for measurement. Both left and right axle spacing 

shall be measured, and the average of two measurements shall be recorded by the nearest cm 

(inches). Each axle spacing shall be made by a single measurement.

N.1.6. Test Procedures. 

N.1.6.1. Dynamic Load Test. – The dynamic test shall be conducted using the test vehicles 

defined in N.1.1. Selection of Test Vehicles and at the load condition as stated in N.1.2. Test 

Loads and at the speed as stated in N.1.4. Test Speeds. The number of runs shall be per 

Table N.1.5.

At the conclusion of the dynamic test, there shall be a minimum of 20 weight readings for 

each single axle, axle group, and gross vehicle weight of each test vehicle. The tolerance for 

each weight reading shall be based on the percentage values specified in Table T.2.3. 

Maintenance Tolerances for Accuracy Class E.

Note. Any vehicle records identified as fault conditions listed in S.1.6. Identification of a Fault or 

jurisdiction defined fault conditions shall be excluded from the minimum weight readings in N.1.5.1. 

Dynamic Load Test.

See Table N.1.6 below to summarize the minimum number of test runs.

Table N.1.6

Minimum Number of Test Runs per Each Test Vehicle

Load Condition Speed

Half Load (10 runs) High Speed Vmax (5 runs)

Low Speed Vmin (5 runs)

Full Load (20 runs) High Speed Vmax (10 runs)

Low Speed Vmin (10 runs)

N.1.6.2. Axle Spacing Test. – The axle spacing test is a review of the displayed and/or recorded 

axle spacing distance of the test vehicles. The tolerance value for each distance shall be based 

on the tolerance value specified in T.2.4. Tolerance Value for Axle Spacing.
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T. Tolerances

T.1. Principles.

T.1.1. Design. – The tolerance for a weigh-in-motion vehicle scale is a performance 

requirement independent of the design principle used. 

T.2. Tolerance Values for Accuracy.

T.2.1. Acceptance Tolerance. – Acceptance tolerance shall be 50% of tolerances in Table T.2.3. 

Maintenance Tolerances for Accuracy. The acceptance tolerance shall apply to a new 

installation or within 30 days of a new installation being placed in service or when an existing 

system undergoes major reconditioning or overhaul.

T.2.2 Tests Involving Digital Indications or Representations. – To the tolerances that would 

otherwise be applied in paragraphs T.2.3. Tolerance Value for Dynamic Load Test, there shall 

be added an amount equal to one-half the value of the system division to account for the 

uncertainty of digital rounding.

T.2.3. Maintenance Tolerance Values for Dynamic Load Test. – The tolerance values 

applicable during dynamic load testing are as specified in Table T.2.3. for direct enforcement 

purposes. 

Table T.2.3.

Maintenance Tolerances for Accuracy 

Load Description* Tolerance as a Percentage of Applied Test Load

Axle Load ± 20 %

Axle Group Load (including bridge formula) ± 15 %

Gross Vehicle Weight ± 10 %

* All weight readings shall be 100% in compliance. 

T.2.4. Tolerance Value for Axle Spacing. – The tolerance value applied to each axle spacing 

measurement shall be ± 0.15 m (6 inches) at 100% compliance.

T.3. Influence Factors. – The following factors are applicable to tests conducted under controlled 

conditions only.

T.3.1. Temperature. –The instrument shall operate within tolerance throughout the specified 

operational temperature range.

T.3.2. Temperature Effect on Zero-Load Balance. – The zero-load indication shall not vary by 

more than one division per 5°C (9°F) change in temperature.

T.3.3. Power Supply. – System shall satisfy the tolerance requirements in Table T.2.3. 

Maintenance Tolerance for Accuracy under voltage ranges of -15% to +10% of the marked 

nominal line voltage(s) at 60 Hz or the voltage range marked by the manufacturer at 60 Hz. 

The battery-operated systems shall satisfy the tolerance requirements in Table T.2.3. 
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Maintenance Tolerance for Accuracy when the battery power output is not excessive or 

deficient.

T.4. Radio Frequency Interference (RFI) and Other Electromagnetic Interference Susceptibility. –

The difference between the weight indication due to the disturbance and the weight indication 

without the disturbance shall not exceed the tolerance value as stated in Table T.2.3. Maintenance 

Tolerances for Accuracy.

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 system 

divisions, value of the system division, or verification system division, and minimum capacity. 

UR.1.1. General. – The typical class or type of device for particular weighing applications is 

shown in Table 1. Typical Class or Type of Device for Weighing Applications.

Table 1.

Typical Class or Type of Device for Weighing Applications

Class Weighing Application

E Enforcing of vehicles based on axle, axle group, and gross vehicle weight.

UR.2. Installation and Maintenance. 

UR.2.1. System Modification. – The dimensions (e.g., length, width, thickness, etc.) of the load 

receiving element of a system shall not be changed beyond the manufacturer’s specifications, 

nor shall the capacity of a sensor 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 system, and by the 

weights and measures authority having jurisdiction over the system.

UR.2.2. Foundation, Supports, and Clearance. – The foundation and supports shall be such as 

to provide strength, rigidity, and permanence of all components. 

On load receiving elements, which use moving parts for determining the load value, clearance 

shall be provided around all live parts to the extent that no contacts may result when the load 

receiving element is empty, nor throughout the weighing range of the system. 

UR.2.3. Access to Weighing Elements. – If necessary, adequate provision shall be made for 

inspection and maintenance of the weighing elements.

UR.3. Maximum Load. – A system shall not be used to weigh a load of more than the marked 

maximum load of the system.

UR.4 Enforcement Guidance. – Prior to the issuance of an enforcement violation, the user shall 

ensure compliance with specific jurisdictional legislation and/or protocols. All gross vehicle, axle, 

and axle group weights must be printed and/or stored with the corrected values that include any 

necessary reductions due to the system tolerance and adopted violation thresholds.
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Add the following definitions to Appendix D:

A

axle. – The axis oriented transversely to the nominal direction of vehicle motion, and extending the 

full width of the vehicle, about which the wheel(s) at both ends rotate. [2.26]

axle-group load. – The sum of all tire loads of the wheels on a group of adjacent axles; a portion of 

the gross-vehicle weight. [2.26]

axle load. – The sum of all tire loads of the wheels on an axle; a portion of the gross-vehicle weight. 

[2.26]

axle spacing. – The distance between the centers of any two axles. When specifying axle spacing, 

the axels used also need to be identified. [2.26]

W

weigh-in-motion (WIM). – A process of estimating a moving vehicle’s gross weight and the portion 

of that weight that is carried by each wheel, axle, or axle group, or combination thereof, by 

measurement and analysis of dynamic vehicle tire forces. [2.26]

WIM System. – A set of load receptors and supporting instruments that measure the presence of a 

moving vehicle and the related dynamic tire forces at specified locations with respect to time; 

estimate tire loads; calculate speed, axle spacing, vehicle class according to axle arrangement, and 

other parameters concerning the vehicle; and process, display, store, and transmit this information. 

This standard applies only to highway vehicles. [2.26]

NIST OWM Detailed Technical Analysis: 

Permanently installed WIM systems are used in several countries around the world and are generally used 

for protection of fragile and critical infrastructure. The submitters clearly showed that there is a need for 

direct and permanent enforcement.

This item was originally submitted in August 2022 and was given an Informational status at the 2023 

Interim meeting. Since the submittal of the item in 2022, the submitters have worked with the S&T 

Committee and NIST OWM to address concerns heard from stakeholders.

During this time, NIST OWM provided the submitters with a list of concerns and a gap analysis 

comparing the proposal to the Scale code in Handbook 44 and OIML R 134 Automatic instruments for 

weighing road vehicles in motion and measuring axle loads. With the proposal under consideration, the 

submitters have addressed most major concerns identified by our office.

The proposal under consideration:

• Leaves the existing code for screening WIM systems in section 2.25. untouched.

• Includes tanker trucks and empty trucks as reference vehicles, where applicable (N.1.2.2.).
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• Includes similar requirements (e.g., voltage variation, definition of acceptance tolerance) as are 

applicable to scales under section 2.20. of Handbook 44 (e.g., T.2. & T.3.).

• Includes guidance when considering penalties for overweight vehicles (UR.4.).

• Does not include any requirements regarding the provision of evidence to support unattended 

operation as this is deemed to fall outside the scope of Handbook 44. The requirement regarding 

the required evidence for unattended operation is left up to the state’s enforcement body.

• Does not include multiple accuracy classes as that could hinder uniformity among the states that 

implement WIM systems for direct enforcement.

The remaining concern is with paragraph N.1.3. Reference Scale which allows the use of a single 

platform vehicle scale to establish the weight of the axles and axle-groups of the reference vehicle. This 

method would require an individual axles or axle-group to be isolated when determining their weight. 

This may work for a vehicle with two sets of axles or the front and rear axles of a vehicle with more than 

two axles but how would you isolate the remaining axles on vehicles with more than two sets of axles?

OWM understands the need for flexibility. Our concern is that it may introduce uncertainty into the 

process of determining reference weight values.

Summary of Discussions and Actions:

At 2023 NCWM Interim Meeting, the Committee has updated this item to the latest version received from 

the submitter. In the most recent version of the proposal, the submitters changed N.1.3. to require the 

reference scale be tested no more than 2 weeks prior to the test of the WIM scale, instead of 24 hours. 

The Committee does not agree with this change and has decided to leave it as currently written in NIST 

HB 44. The Committee continues to work on this item, including User Requirements, to address concerns 

it heard during the NCWM Interim. The submitters intend to provide a demonstration of a WIM scale in 

use in the near future. The Committee has decided to leave the item as informational and encourages the 

submitters to continue to work with the committee, NIST OWM, and stakeholders for further 

development.

Regional Association Reporting:

Western Weights and Measures Association

At the 2022 WWMA Annual Meeting, Tanvi Pandya (New York City DOT) stated technologies have 

moved on. Tanvi Pandya noted New York City DOT has data since 2019 showing that accuracy can be 

met on the devices. They added the Handbook is outdated and needs to be updated to provide a way to 

enforce and it cannot be overstated the number of overweight vehicles that need to be regulated. Tanvi 

Pandya recommended a Voting status.

Chaekuk Na (Rutgers University) stated the submitters of the item tried to meet the standard and got less 

than 6 % error with 100 % compliance. They stated Indiana DOT conducted an independent test and 

received results within 5 % error.

Jess Helmlinger (Kistler Group) clarified Chaekuk Na’s comments regarding test loads with testing 

occurring with both loaded and unloaded vehicles in live traffic and static weights for fairness. They 
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noted changing the test procedure on live traffic and status weights had no impact. Jess Helmlinger made 

reference to the current tentative code for the tolerances are wide and questioned how to test currently –

use live trucks and a reference scale. They confirmed this is for law enforcement and not commercial 

weighing and the submitters have worked with NIST and a multitude of states. They also stated the item 

is intended for states that want to use automated enforcement and would not force any jurisdiction to use 

it. Jess Helmlinger recommended a Voting status.

Matt Douglas (State of California, Division of Measurement Standards on behalf of S&T Committee) 

sought clarification about the line inside the proposed tolerance table and what the purpose of the second 

statement. On the last line in the table, it says that the gross vehicle weight shall be ± 10 % but it also 

says ± 6 %.

Jess Helmlinger addressed Matt Douglas’s comments and clarified the 6 % is for gross vehicle weight 

with a 95 % compliance. They referred to the proposed tolerance table and noted the outcome cannot 

have more than 5 % of the values outside the tolerance. Jess Helmlinger stated if any value is outside of 

10 % accuracy, then it fails the test. 95 % of the values must be within the values.

Jan Konijnenburg (NIST Associate) confirmed NIST has been involved with this item but has not 

reviewed the proposal in detail to come to a conclusion. Jan Konijnenburg made reference the WIM code 

that currently exists is idle and obsolete. Jan Konijnenburg acknowledged this is a method of a WIM 

system enforcement. Jan Konijnenburg stated he is looking forward to how this will develop. Jan 

Konijnenburg made no recommendation at this time for the status of this item.

Raymond Johnson (Fairbanks Scales, Inc., representing the Scale Manufactures Association) commented 

the SMA has not met and has not formulated a position on this item. Johnson commented the SMA is 

scheduled to meet in November 2022.

Matt Douglas believes that there is some merit to some of the item. Douglas recommended keeping the 

accuracy class “A” and add accuracy class “E”.

Kenn Burt (San Luis Obispo County, California on behalf of S&T Committee) sought clarification if 

industry has seen this proposal and understand what they might be dealing with regard to how the WIM 

system will be used and applied for enforcement?

Tanvi Pandya addressed Kenn Burt’s question regarding industry reviewing this item. They commented 

the submitters have met regularly and developed a task force. Tanvi Pandya commented the task force 

has discussed this for the past several months. They also commented they have not directly engaged with 

the trucking industry but have spoken with some freight industry in general.

Jess Helmlinger commented the Commercial Vehicle Safety Alliance (CVSA) has been made aware of 

this item.

During Open Hearings there was testimony that neither the SMA nor NIST has evaluated this proposal. 

The committee looks forward to the analysis of this item by NIST and SMA. The Committee asked the 

submitters questions about the tolerance table “T.2.2. Tolerances for Accuracy Class E”, specifically the 

last line in the table. The submitter clarified their statement made during open hearings in the Committee 

work session. The Committee recommended that the submitter consult the Scales Code for similar 

applications to expressing tolerances.

The WWMA S&T Committee recommended that this item be assigned a Developing status. 
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At the 2023 WWMA Annual Meeting, a presentation was given from the submitters of this item 

regarding updated language provided for consideration and posted on the WWMA website, Events –

Meeting Documents – WIM.23-1 Proposed Language. The submitters spoke to:

- This device is not a scale in the traditional application and intended for use dynamically of 

overweight vehicle enforcement.

- The intent is to remove the “Tentative” status for Class E devices. The “Tentative” status would 

remain for Class A devices.

- A demonstration was conducted on a similar device in April 2023.

- This application would exclude all liquid tank trucks.

- It is difficult to be consistent with vehicle positioning. The submitter clarified that if the vehicle is 

not in the correct position the system will default to “Error”. This “Error” is an appropriate 

performance function.

Cory Hainy (SMA) remarked the association formed a position in April 2023 of opposition to this item 

prior to the updated language being proposed and will meet in November 2023 to reassess the item. It 

was reemphasized that the proposed tolerances were a point of contention with the association. The 

association would like to see revisions that address dynamic weighing should not be allowed a greater 

tolerance, acceptance and maintenance tolerances should be applied, and harmonizing existing tolerances 

with the scale code.

Loren Minnich (NIST OWM) stated OWM reached out to the submitter to clarify the intention regarding 

tentative and permanent status for “Class A” and “Class E” devices subject to this code. Examples were 

provided in open hearing of existing code such as Grain Analyzers as an example of separating this code 

for enforcement and screening purposes.

The committee posed the following questions:

- Can the submitter clarify the intent of all weights for 100% compliance regarding the applicable 

tolerances?

The submitter response clarified the device should perform within the applicable tolerances at all test 

loads and that a fault qualifies towards the 100% compliance.

- Can the submitter clarify what is meant by 100% compliance regarding T.2.4?

The submitter clarified the axle spacing must be predetermined by the inspector and must match the 

device. The system will identify a bridge formula violation and the inspector has to accurately 

measure the axle spacing and then verify the system measurement within the tolerance specified with 

T.2.4

- Can the submitter provide data to support the ± 10 % to 20 % tolerance range?

The submitter response clarified the intent of the use of the device is for dynamic and not static 

weighment. Scales currently function at a lower range of 6 % but the addition of the 100 % 
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compliance is to justify the tolerance. It was expressed the intention of the proposed code is to 

enforce grossly overweight vehicles.

The submitter clarified the 100 % compliance came from the original proposed 95 % compliance. The 

submitter clarified 100 % of the total number of runs would need to be within tolerance.

- Can the body please clarify how or if 2.20 scale code regarding WIM systems and the proposed WIM 

system code will impact each other?

Loren Minnich clarified each section of the existing code has an application section to identify what 

devices are covered by that code. The application section for each code should be reviewed to verify 

that there is no overlap.

Cory Hainy (SMA) raised concern regarding tolerances specifically whether OIML R 134-1 standards 

where considered.

Chaekuk Na (Rutgers) stated OIML 134-1 standards were considered and that there are different levels of 

accuracy. The tolerances selected are currently being used in other countries and the F-10 for 10 % gross 

meet the proposed tolerances.

Cory Hainy (SMA) reinforced the concern regarding the large tolerances and spoke to already existing 

tolerances. Existing scales are held to certain standards even if used for law enforcement purposes.

Tanvi Pandya (New York DOT) clarified this is a dynamic test and supports the tolerances as written.

Aaron Yanker (Colorado Dept. Ag Weights and Measures) questioned the note in Table 1. The submitter 

responded the note regarding the higher accuracy class is original language of the item.

The WWMA S&T Committee recommends that the NCWM S&T Committee consider incorporation of 

the updated language as provided by the submitter and that this item remain Informational. This will 

allow stakeholders to provide comments on the updated language. We further recommend that NCWM 

S&T Committee consider the comments and questions which came up in the WWMA S&T Open Hearing 

Session while further developing the item with special attention to the comments from NIST OWM.

Updated language will be included in the WWMA S&T Committee 2023 Final Report as an Appendix to 

the item.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Dr. Nasif presented a presentation he stated that the device 

currently operates within 6 % of the Type III ASTM Standard. The submitter stated that their intentions 

is for direct enforcement fines to not apply within 10 % of weight limit based on local enforcement 

procedures.

Peter Fedechko (International Road Dynamics) supported this item.

Tim Chesser (Arkansas) stated that he liked the language on page 167 lines 25-28. They asked why strike 

paragraph B and they also cited some errors on page 170.
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Paul Floyd (Louisiana) stated that he has concerns about the accuracy of this system. He stated that he 

would support this item for screening purposes and recommends it moving forward as Developing.

The SWMA S&T Committee asked about the speed and weight requirements used for testing in the 

proposal not matching with what the devices will be used to regulate. The Committee also questioned 

whether these devices would receive a type evaluation from NTEP if specifications were added to the 

handbook. Additionally, the Committee questioned whether a direct enforcement procedure should be 

separated from the tentative screening code.

The SWMA S&T Committee recommended this item move forward as a Developing Item.

At the 2023 SWMA Annual Meeting, Tanvi Pandya (NYC DOT and co-submitter) gave a presentation on 

the item. They had some edits since the July report. They stated these systems are used internationally, 

and it isn’t realistic to statically weigh the 10 % of all trucks that are overweight on the road. Tanvi 

Pandya feels the tolerance is acceptable for enforcement purposes. They stated that this device is to be 

used for law enforcement and screening purposes only and not commercial applications. They noted some 

jurisdictions have raised concerns to her about removing the tentative status. Tanvi Pandya also stated 

that have not had a chance to resolve some issues with NIST, and that the New York Department of 

Agriculture is requiring a corresponding code in Handbook 44 before they will certify the weighing 

system.

Chaekuk Na (Rutgers University and co-submitter) stated they are trying to harmonize the language in the 

item with the OIML code. Chaekuk Na stated fuel consumption of the test vehicle is not relevant due to 

the large tolerances allowed in their current code.

Cory Hainy (SMA) stated they are opposed to the item and have not had a chance to review the latest 

revision. SMA stated they are concerned that enforcement scales are already defined, acceptance and 

maintenance tolerances have not already been established, and that adding it to the WIM code will create 

two conflicting law enforcement codes. The specifics of their concerns are in their April positions from 

SMA.

Tim Chesser (Arkansas) echoed Cory Hainy’s position and asked what other states besides New York and 

Maryland plan to use this code? Tim Chesser also raised a concern that once this code is in the handbook 

some states would be forced to enforce it. They also stated the tolerances were too wide for enforcement. 

He also expressed concern about the axle spacing measurement being confusing.

Alison Wilkinson (Maryland) raised concerns about the lack of standards, the use of the word “may”, and 

stated the reference scale code is vague in regard to testing logistics such as how far or near the reference 

scale should be to the system being tested. They also raised concerns about the fuel consumption of the 

test vehicles. Alison Wilkinson stated Maryland is opposed to this item, and that agrees with Tim 

Chesser’s comments. They believe this code should only be used for screening. 

Mauricio Mejia (Florida) agreed with the concerns raised by other commenters, questioned whether this is 

the proper channel for this type of code, and that it should only be used for gross vehicle weight. 

Juana Williams (NIST OWM) has concerns about combining tentative and non-tentative codes. Juana 

Williams stated NIST OWM is of the opinion that acceptance tolerance should be 50 % of the 

maintenance tolerance. They also stated that this code should cover all vehicles, including those carrying 

liquids and empty vehicles.
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John Stokes (South Carolina) agreed with Arkansas in opposition to the item. Robert Huff (Delaware) 

stated this item will result in numerous complaints that they will not be able to handle.

The Committee heard no comments in support of this item from the SWMA membership and suggests 

that the NCWM S&T Committee work with the submitters and NIST to address the issues raised.

The Committee recommends the item remain as an Informational item.

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting, a presentation was given from the submitters of this item. The 

submitters reminded the body that this item deals exclusively with law enforcement scales, and not 

commercial scales. 

John McGuire (New Jersey) inquired about a 10 % leeway in gross weight and believes that if a law 

enforcement agency is writing summonses, the tolerance should be tighter. They also inquired if the 

SMA and NIST had a position on this proposal. 

Dawn Harrison (New York City Department of Transportation) indicated that the 10 % leeway was 

chosen as a local enforcement policy because they believe that percentage on gross vehicle weight falls 

within tolerances of WIM systems and wants to target heaviest offenders. Any violations written by law 

enforcement have to be reviewed prior to issuance. 

Jess Helmlinger indicated the system will be tested to a 6 % tolerance and fines would be issued at 10 %.

Jim Willis (New York) stated their understanding is there is a concern with both axel weights and gross 

weights of the overweight vehicles. 

Diane Lee (NIST OWM) inquired if this system will be used to provide official weight or estimation, and 

if weight is not correct are they going to weigh station to get official weight. 

Jess Helmlinger indicated that during testing, they will be tested with a certified field reference scale and 

vehicles. 

Jason Flint (New Jersey) pointed out that the 10 % leeway is a local enforcement decision and will not 

appear in the handbook as a tolerance. 

Jim Willis has concerns with the number of runs required to test the system. Roy Czinku (International 

Road Dynamics) stated that WIM is a mature technology and can provide reliable output and weighments. 

John McGuire (New Jersey) recommended the item as developing so a further look can be taken into the 

dynamics of WIM. Jason Flint (New Jersey) suggested that an on-site demonstration be made available 

so regulators can view the system being used.

After hearing comments from the floor, the Committee agreed that the item has merit. Considering the 

underlying questions about tolerances and test procedures, the Committee is recommending a Developing 

status.

At the 2023 NEWMA Annual Meeting, the submitters of this item gave a presentation to that outlined 

new information, changes to language in the item under consideration and a synopsis on a live demo that 
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occurred in Wisconsin. The submitters stated that this system is for enforcement purposes only, not 

commercial, and weigh-in-motion sensors are more efficient than using a static scale in high traffic areas 

where overweight vehicles are a problem. The submitters met with many stakeholders, industry and 

government officials for feedback to change certain testing procedures such as requiring a straight run 

only, instead of left/right, and possibly replacing the empty load test with a half load test. 

Jim Willis (New York) stated that the demo was good experience and indicated that this is a sensor 

system and not a scale. Sensors are good at what they do, but they are not a scale. During the 

demonstration, the only issue with reliability was an empty truck where the back wheel bounced and 

registered 17 % light.

NIST noted that the system constantly “optimizes” the sensor system using previous readings to make

corrections, can the system be rechecked? 

The submitters stated the system has an audit trail and a data logger that is locked with a tag that collects 

all calibrations that are done and can give a report. 

Michael Keilty (Endress + Hauser) asked how weather effect the system. The submitters stated there is 

data collection ongoing and there is system-based compensation for temperature. 

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

an Informational status, and the body concurred. The Committee commends the submitters for the hard 

work in developing this item and involving all stakeholders.

At the 2023 NEWMA Interim Meeting, a presentation was given by submitters with updates to the item, 

including having 2.25 remain tentative for screening and creating 2.26 for enforcement. The submitters 

are working with NIST to finalize language and the updated proposal after taking feedback from the 

regions. The State of NY recommends voting. The Commonwealth of PA questions if it should be in the 

handbook. The States of New Hampshire, New Jersey, and the Commonwealth of Massachusetts 

supports as voting. Upon consensus of the body, the Committee recommended this item be Voting with 

the upcoming changes to the item.

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, Hani Nassif stated that overweight percentages of trucks are 

impacting roadways and bridges. The screening process in the existing tentative code doesn’t apply to 

enforcement of overweight commercial trucks.

Jess Helmlinger stated that the tentative code has large tolerances and that’s why it isn’t being used by 

most states. The technology has improved to 4 % or 5 % tolerance capability since the tentative code was 

written. The tentative screening code doesn’t hold up in court when overweight tickets are challenged. 

These changes are for law enforcement purposes; not necessarily commercial. The intent is not to 

require adoption, but to allow the use by states who wish to utilize it. 

Doug Musick (Kansas) stated that testing involves three truck classes, three different loads, and three 

different speeds. Is the intention that there are different classes of trucks which are all tested at all three 

different loads and speeds? What does FHWA mean? Spell out the acronym. Is that in a C.F.R. which 

can be referenced?
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Loren Minnich (Kansas) remarked that page 168, S.1.7.1. is missing the lettering, but it’s that way in the 

tentative code and formatting needs fixed. Don’t get rid of the current screening aspect of the tentative 

code. They supported this item moving on its own and not take away the ability of jurisdictions to use the 

tentative code for screening. They suggested adding a second class?

The CWMA S&T Committee recommended this as a Developing Item. The Committee would like more 

input from jurisdictions who would be affected by removing the screening aspect of the tentative code.

At the 2023 CWMA Annual Meeting, Greg VanderPlaats (Minnesota) recently attended a demonstration 

of a WIM system for highway weight screening and compared contrasted the WIM with a stationary 

scale. The WIM met tolerances, but they are large i.e., 10 % to 20 %. The WIM system can meet the 

tolerances but work still needs to be done. How will the tolerances be used for actual enforcement? 

Adding the tolerance to the weight limit before enforcement is taken. Will have to coordinate with DOT / 

enforcement because W&M officials will not be applying this code. WIMs are needed in populated 

northeast where static scales cannot be located near aging infrastructure (bridges).

Thomas Schuller (Scale Manufacturers Association) remarked that the SMA opposed this item with the 

following concerns:

• Highway weight enforcement scales are already defined as Class IIII in the Scales code.

• -Dynamic weighing should not perform worse than what has already been established and is 

acceptable.

• These devices will suffer major usage, so an acceptance and maintenance tolerance should be 

established similar to Class IIII values.

• Tighter tolerances will contribute to better performance and would detect more overweight 

vehicles and generate higher revenue.

• If added to the WIM Code, law enforcement code would exist in both the Scales code and the 

WIM code that needs to be reconciled.

• If this item stays in WIM and does move forward, our recommendation would be to harmonize 

tolerances with OIML R134.

• The WIM code was not intended to be used in Commercial applications. Commercial and Law 

enforcement weighing applications, including WIM applications, are covered in the Scales Code.

Jan Konijnenburg (NIST OWM) spoke that this item has merit and supported further development. Does 

not agree with the SMA’s position. The WIM Code will not be commercial and will be for law 

enforcement use only. Agrees with aligning with OIML R134.

The CWMA S&T Committee recommends this item remain Informational.

At the 2023 CWMA Interim Meeting, Tanvi Pandya and Chaekuk Na presented on behalf of the 

submitters outlining the changes that have been made to address previous concerns.

Mike Harrington (Iowa) supports this item and recommends it moving forward as voting.
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Greg VanderPlaats (Minnesota) commented that the submitters have done a lot of work and have made 

changes per the feedback received at the National Conference and supports this item as voting.

The Committee recommends this item moving forward as a Voting item with the proposed changes by the 

submitter which are attached to the end of this report. [APPENDIX B]

Scale Manufacturers Association (SMA)

At the 2022 SMA Fall Meeting, the SMA supported removing the tentative status from this code and it to 

remain used for Vehicle Screening only.

Rationale: This code is not intended to be used in Commercial applications. Commercial weighing 

applications, including WIM applications, are covered in the Scales code.

At the 2023 SMA Spring Meeting, the SMA opposes this item with the following concerns.

Major points of concern:

• Highway weight enforcement scales are already defined as Class IIII in the Scales code. 

Dynamic weighing should not perform worse than what has already been established and is 

acceptable.

• These devices will suffer major usage, so an acceptance and maintenance tolerance should be 

established similar to Class IIII values. Tighter tolerances will contribute to better performance 

and would detect more overweight vehicles and generate higher revenue.

• If added to the WIM code, law enforcement code would exist in both the Scales code and the 

WIM code that needs to be reconciled.

• If this item stays in WIM and does move forward, our recommendation would be to harmonize

tolerances with OIML R134. 

Rationale:

The WIM code was not intended to be used in Commercial applications. Commercial and Law 

enforcement weighing applications, including WIM applications, are covered in the Scales code.
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LMD – Liquid Measuring Devices

LMD-24.1 N.4. Normal Tests

NOTE: This item was introduced through the Northeastern Weights and Measures Association.

Source: New Hampshire Department of Agriculture, Markets, and Food

Submitter’s Purpose and Justification:

Provide clarity to 3.30. Liquid—Measuring Devices, N.4.1. Normal Tests. The existing code requirement 

is very wordy and difficult to understand without an example and a formula. This proposal adds an 

example and formula that will give clarity to N.4.1. Normal Tests. 

The additional language will be one of several other NIST HB 44 codes that give clarifying examples.

NIST has indicated that in the near future the handbooks will not be printed but will be digitally 

produced. Therefore, we are no longer constrained by the size of the handbook if the information adds 

value.

The problem can be resolved through more thorough training. We were informed that a formula can be 

added, however, an example will make the handbook longer and it sets a precedence for adding examples 

in the future.

The submitter requested Voting status in 2024.

NIST OWM Executive Summary for LMD-24.1 – N.4. Normal Tests

NIST OWM Recommendation: Voting with recommended changes.

• For the 2024 edition of NIST Handbook 44, OWM made editorial changes to this paragraph 

based on a request from the submitter of this item. This is the how the paragraph now appears 

in the handbook:

N.4.1. Normal Tests. – The “normal” test of a device shall be made at the maximum 

discharge flow rate developed under the conditions of installation. Any additional tests 

conducted at flow rates down to and including one-half of the sum of the maximum discharge 

flow rate (MDRF) and the rated minimum discharge flow rate (RMDFR) shall be considered 

normal tests. As a formula, this is stated as:

MMMMMMMM+

2 = h aa ff ff ff for additional tests

(Amended 1991 and 2023)

• For added clarification we suggest adding the word “normal” between the words “additional” 

and “tests” in the formula so it would appear as follows:
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MMMMMMMM+

2 = h aa ff ff ff for additional normal tests

• To be consistent with other examples currently in NIST Handbook 44, OWM suggests the 

following format for the example proposed by the submitter:

Example: If, under the conditions of installation, a device has a maximum discharge flow 

rate (MDFR) of 9 gpm and a rated minimum discharge flow rate (RMDFR) of 0.5 gpm, 

using the above formula the minimum discharge flow rate for additional normal tests is 

calculated as follows:

99 gg + 00. 55 gg

22 = 44. 77 gg

For this device any test conducted at a flow rate of 9 gpm down to and including 4.75 gpm 

is considered a normal test and the acceptance or maintenance tolerances referenced in 

Table T.2. Accuracy Classes and Tolerances for Liquid Measuring Devices covered in 

NIST Handbook 44, Section 3.30. are applicable.

Tests conducted below the minimum discharge flow rate for additional normal tests are 

considered “special” tests and shall be conducted as described in N.4.2. Special Tests.

The special test tolerances referenced in Table T.2. Accuracy Classes and Tolerances for 

Liquid Measuring Devices covered in NIST Handbook 44, Section 3.30. are applicable.

• If the S&T Committee accepts the format for the example suggested by OWM, our office will 

support this item for adoption.

• OWM notes that in the Item Under Consideration the proposed new language is in in bold type 

and should be edited as such so it is clear to the reader that this is new language.

Table 2. Summary of Recommendations

LMD-24.1 – N.4. Normal Tests

Status Recommendation Note* Comments

Submitter Voting

OWM Voting With suggested edits

WWMA 4

NEWMA Voting

SWMA 4

CWMA 4

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers
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Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44 Liquid Measuring Devices Code as follows:

N.4. Testing Procedures.

N.4.1. Normal Tests. – The “normal” test of a device shall be made at the maximum discharge 

flow rate developed under the conditions of installation. Any additional tests conducted at flow 

rates down to and including one-half of the sum of the maximum discharge flow rate and the rated 

minimum discharge flow rate shall be considered normal tests.

(Amended 1991)

Example: 

• Maximum rated flow rate is 12 gpm / Minimum rated flow rate is 0.5 gpm. 

• Maximum discharge flow rate developed under conditions of installation is 9 gpm 

= normal test

• Additional normal tests are determined using the following formula: 

MM MM dd dd ddgg ff ffff + mmmmmmdd dd dd ff ffff

22 =

mm mmmmmm dd dd dd ff ffff

• In this example 99 gg + 00.55 gg

22 = 44. 77 gg . Therefore, flow rates of 9 gpm down 

to and including 4.75 gpm are considered normal tests.

(Added 202X)

Regional Association Reporting:

Western Weights and Measures Association

Central Weights and Measures Association

Southern Weights and Measures Association

Northeastern Weights and Measures Association
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At the 2023 NEWMA Interim Meeting, a regulator from New Hampshire commented that the test 

procedure, as currently written, is difficult to understand, specifically in the second sentence. The 

purpose of the proposal is to add an equation and give an example of the equation, adding a value and 

clarity to the handbook. The State of New York commented that other codes, such as LPG, has the same 

language and may also need to be updated in the future but agrees the proposal has merit. The 

Commonwealth of Pennsylvania commented that clarity is an added advantage in the field and makes a 

difference to help regulators and industry understand the testing methods. It was also suggested that if 

this does not appear in the handbook, then it could possibly be worked into the NCWM field testing 

manual. The State of New Jersey concurs. Upon consensus of the body, the Committee recommends this 

item as a Voting item.

VTM – Vehicle Tank Meters

VTM-20.2 A Table T.2. Tolerances for Vehicle Mounted Milk Meters.

(Note: This item was revised based on changes that were made by the Committee at the 2021 NCWM 

Interim Meeting.)

(Note: The Item Under Consideration was removed from the voting consent calendar at the 2021 NCWM 

Annual Meeting and the S&T Committee made this a Developing Item.)

Source: POUL TARP A/S

Submitter’s Purpose and Justification:

Change tolerances to accommodate more efficient milk-metering systems.

NIST OWM Executive Summary for VTM-20.2 – Table T.2. Tolerances for Vehicle Mounted Milk 

Meters

NIST OWM Recommendation: OWM supports the Assigned status for this item and encourages the 

Task Group to continue its review of the proposed OIML tolerances for Vehicle Tank Milk Meters.

• One of the concerns raised is that the proposal includes tolerances for the system and a separate 

tolerance for the meter. 

• NIST OWM observed that a separate tolerance for the meter would apply during OIML type 

evaluation. However, NIST HB 44 only includes requirements for the entire measurement 

system and not separate main elements nor does it have separate tolerances for main elements 

known to be metrologically significant. 

• Aaron Yanker (Colorado) is listed on the NCWM website as the Milk Meter Task Group Chair 

NIST OWM will look forward to more discussion of this item during task group meetings.
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Table 2. Summary of Recommendations

VTM-20.2 – Table T.2. Tolerances for Vehicle Mounted Milk Meters

Status Recommendation Note* Comments

Submitter Voting

OWM Assigned

WWMA Assigned

NEWMA Withdrawn

SWMA Assigned

CWMA Assigned

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry 4 Agri-Mark, Dean Foods, Dairy Farmers of America, 

Danone North America

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Vehicle-Tank Meters Code as follows: 

T.2. Tolerance Values. – Tolerances shall be as shown in Table 1. Accuracy Classes and 

Tolerances for Vehicle-Tank Meters Other Than Vehicle-Mounted Milk Meters and Table 2. 

Tolerances for Vehicle-Mounted Milk Meters.

(Amended 1995 and 20XX)

Table 2. Tolerances for Vehicle-Mounted Milk Meters

Indication

(gallons)

Maintenance Tolerance

(gallons)

Acceptance Tolerance

(gallons)

100 0.5 0.3

200 0.7 0.4

300 0.9 0.5

400 1.1 0.6
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Indication

(gallons)

Maintenance Tolerance

(gallons)

Acceptance Tolerance

(gallons)

500 1.3 0.7

Over 500 Add 0.002 gallon per indicated 

gallon over 500

Add 0.001 gallon per indicated gallon 

over 500

(Added 1989)

Table 2. Tolerances for Vehicle-Mounted Milk Meters

Acceptance Tolerance Maintenance Tolerance

Complete Measuring System 0.5 % 0.5 %

Meter Only 0.3 % 0.3 %

(Amended 20XX)

NIST OWM Detailed Technical Analysis: 

The Milk Meter Task Group last met on January 3, 2022 to further discuss the proposed tolerances for 

Milk Meters. This is a proposal to increase the tolerances for vehicle mounted metering systems that 

measure milk and the proposed tolerance are those used in OIML for milk measuring systems.

Proposed Tolerance

Current NIST 

Tolerance

Proposed 

Tolerance

Current NIST 

Tolerance

Collected volume Maintenance Maintenance Acceptance Acceptance

Gallon Percent % Gallon Percent % Gallon Percent % Gallon Percent %

50 Gallon 0.25 0.5 % 0.25 0.5 %

100 Gallon 0.5 0.5 % 0.5 0.50 % 0.5 0.5 % 0.3 0.30 %

200 Gallon 1 0.5 % 0.7 0.35 % 1 0.5 % 0.4 0.20 %

300 Gallon 1.5 0.5 % 0.9 0.30 % 1.5 0.5 % 0.5 0.17 %

400 Gallon 2 0.5 % 1.1 0.275 % 2 0.5 % 0.6 0.15 %

500 Gallon 2.5 0.5 % 1.3 0.26 % 2.5 0.5 % 0.7 0.14 %

The submitter explained that use of vehicle mounted metering systems to measure milk reduces the 

amount of time needed to collect and process the milk which reduces the cost and loss of product that 

would occur with a slower measurement process. But, with the use of vehicle mounted measuring 

systems, entrained air is produced that cannot be removed and this air is measured as product. As such, 

with the use of a pump metering system there is an inherit loss to the buyer. Although the system has 

means for air elimination, not all entrained air can be removed and this is the submitter’s reason for 

requesting that the tolerances currently in the HB be increased. 

Poul Tarp also noted that it is recognized by the European Standardization Agencies: Measuring 

Instrument Directive (MID) and Organization of Legal Metrology (OIML) Recommendation (R) 117 
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Dynamic measuring systems for liquids other than water and the dairy industry in general that it is not 

possible to remove all the air from milk before measuring it. Poul Tarp notes the MID and OIML (R) 117 

standards specify that measurements of a vehicle mounted milk metering system must not result in 

inaccuracy of more than 0.5 % at any given amount being collected from a minimum of 50 gallons and up 

to +500 gallons. NIST HB 44 Section 3.31.has a designated tolerance table in volume for vehiclemounted milk meters that was added to the code in 1989 with an acceptance tolerance of 0.3 and 

maintenance tolerance of 0.5 gallons for the first 100 gals and these tolerances decrease in percent 

tolerance as the indicated volume increases, as was reported in a presentation from Poul Tarp: 

NIST OWM’s initial points to consider as the Committee began to deliberate on the proposal were:

– Are there other methods that can be employed to remove entrained air from the milk?

– Can the amount of error introduced from entrained air be determined? 

– Should NIST HB 44 tolerances be aligned with OIML R 117 less stringent tolerances, as 

recommended by the submitter.

– Should there be a separate tolerance table to address vehicle mounted metering systems?

During the 2019 NCWM Interim Meeting another company stated that they met the current tolerances in 

NIST HB 44 and were issued an NTEP certificate and believe that the current tolerances are appropriate. 

Other State regulators commented that the current certificate was limited to testing up to 300 gallons. At 

that time the S&T Committee assigned a task group to this item and NIST OWM expressed interest in 

working with the Task Group. 

Charlie Stutesman (Kansas and Chair of the Task Group) sent an email to the Milk Meter Tolerance Task 

Group (TG) providing a list of the TG members and the TG’s mission. Charlie Stutesman also informed 

the Task Group that most communication will be conducted via e-mail and that face-to-face meetings will 

be planned at Interim and Annual Meetings.

The following list contains the names of members on the Milk Meter Tolerance TG:

Chair – Charlie Stutesman (Kansas)

NEWMA Representative – Jim Willis (New York)

SWMA Representative – TBD

WWMA Representative –Jeff Cambies (California)

NTEP Technical Advisor – Mike Manheim

NIST Technical Advisor – Diane Lee

Measurement Canada Technical Advisor –Luciano Burtini 

Industry Representative – Carey McMahon (Poul Tarp)

Industry Representative – Leigh Hamilton (Piper Systems)

Industry Representative –Brandon Meiwes (Dairy Farmers of America)

Industry Representative – Bob Fradette (Agri-Mark)

Mitch Marsalis (Los Angeles County, California) has agreed to be the SWMA representative. I am just 

waiting on formal assignment by the NCWM Chair for Mitch.
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Milk Meter TG Mission:

The mission of the Task Group is to review and possibly recommend changes to the tolerances that apply 

to milk meters, which may include milk measuring systems, in Sections 3.31. Vehicle Tank Meters, 

Section 3.35. Milk Meters, Section 3.37. Mass Flow Meters, and Section 4.42. Farm Milk Tanks. This 

TG will consider the tolerances proposed in S&T item VTM-20.2 and the tolerances in OIML R 117-2 

“Dynamic measuring systems for liquids other than water” in their discussion.” 

Charlie Stutesman provided the Task Group with milk meter tolerances and requirements from OIMLR117-2: 2007, NIST HB 44 Tolerances for Milk Meters that are located in the VTM Code Section 3.31, 

the Mass Flow Meter Code Section 3.37, and the Farm Milk Code Section 4.42 and Measurement 

Canada’s tolerances for milk meters and requested feedback from the task group on appropriate tolerances 

to apply. A Task Group member from Poul Tarp, the original submitter of the item, recommended that 

the proposal be changed to align NIST HB 44 with the tolerances for milk meters in OIML R-117-2. 

Charlie Stutesman circulated a proposal for consideration by the task group that would aligns the 

tolerances in NIST HB 44 Section 3.31 Table 2 with OIML to tolerances. OIML Tolerances seem to 

apply two different tolerances. 0.5 % tolerance for milk meters in a system and 0.3 % tolerance for a 

meter outside of a system that is used to measure milk. The proposed tolerances and changes to NIST HB 

44 are provided below:

Table 2. Tolerances for Vehicle-Mounted Milk Meters

Indication

(gallons)

Maintenance Tolerance

(gallons)

Acceptance Tolerance

(gallons)

100 0.5 0.3

200 0.7 0.4

300 0.9 0.5

400 1.1 0.6

500 1.3 0.7

Over 500 Add 0.002 gallon per indicated 

gallon over 500

Add 0.001 gallon per indicated gallon 

over 500

Table 2. Tolerances for Vehicle-Mounted Milk Meters

Indication

(gallons) Acceptance Tolerance Maintenance Tolerance

Complete Measuring System 0.5 % 0.5 %

Meter Only 0.3 % 0.3 %

Proposed change to Handbook 44- Simple rewrite of Table 2 and paragraph T.4. in 3.31 VTM Code and 

Table 1 in 3.35 Milk Meter Code.

3.31. Vehicle Tank Meters

T.2. Tolerance Values. – Tolerances shall be as shown in Table 1. Accuracy Classes and Tolerances for 

Vehicle-Tank Meters Other Than Vehicle-Mounted Milk Meters and Table 2. Tolerances for Vehicle-
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Mounted Milk Meters.

(Amended 1995 and 20XX)

If changes to the product depletion test tolerances in Handbook 44 are made to match OIML R117-1 

paragraph 2.10.1:

T.4. Product Depletion Test. – The difference between the test result for any normal test and the 

product depletion test shall not exceed 0.5 % of the volume delivered in one minute at the maximum flow 

rate marked on the meter for meters rated higher than 380 Lpm (100 gpm) or 0.6 % of the volume 

delivered in one minute at the maximum flow rate marked on the meter for meters rated 380 Lpm (100 

gpm) or lower. Test drafts shall be of the same size and run at approximately the same flow rate. For 

vehicle tank meter measuring systems used to measure milk, the effect due to the influence of the 

air or gases on the measuring result shall not exceed 1.0 % of the quantity measured.

Charlie Stutesman also asked the Task Group if consideration should be given to updating all of the codes 

pertaining to milk metering devices in NIST HB 44 and if all milk metering requirements should be 

included in a single code. 

The NCWM Milk Meter Tolerance Task Group met virtually on January 7, 2020. During this meeting 

the Task Group discussed:

– the system of milk collection from farm to processer (seller to buyer), 

– the operation of metering systems that measure milk to include discussion of air elimination 

systems,

– review of the milk measuring tolerances in NIST HB 44 from 1919 to 2020,

– review of the proposal to harmonize the NIST HB 44 VTM code milk metering tolerances with 

OIML tolerances for single milk meters and milk meter measuring systems, and

– whether or not the Task Group wanted to consider expanding its scope to include combining all 

milk metering requirements in NIST HB 44 to a single code. 

By consensus the Task Group agreed with harmonizing the VTM milk metering tolerance with OIML R 

117 tolerances and that those tolerance be presented during the NCWM 2021 Interim Meeting for 

discussion. The Task Group also agreed that a request should be made to the S&T Committee to expand 

the scope of the Task Group to include combining milk meter requirements in NIST HB 44 to a single 

code.

Charlie Stutesman (TG Chair) proposed the TG visit a location to review Milk Measuring systems in use 

as its next step. The Task Group last met on July 1, 2021. 

NIST OWM is looking forward to gaining additional information on the various systems for milk 

metering and their capabilities and believes the task groups plans to visit a site will be helpful in 

determining the best approach for acceptable solution for milk metering systems. In the meantime, 

harmonizing with OIML tolerances may be an acceptable path forward. OWM reiterates its original 

questions concerning the operation of milk metering systems. OWM encourages the task group to 

continue its investigation of these systems.
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Summary of Discussions and Actions:

A Milk Meter Tolerance Task Group was formed and assigned to this item. Please contact the Task 

Group Chair for more information:

Aaron Yanker

Program Administrator

aaron.yanker@state.co.us

Phone number: (719) 250-1851 Fax number: (303) 466-2860

Existing tolerances are based on the accuracy of the Flow meter itself. The proposed Tolerances are 

based on Milk Metering Systems where the magnetic flow meter is a part of the Milk Metering system 

handling milk containing air.

The accuracy of the Flow meter will always be influenced by the way it is used. The only way you can 

obtain the accuracy described by the manufacture is when the flow meter is operating as a “stand alone” 

unit and, equally important, only if the product passing through the flow meter is complete air-free.

The submitter provided the following:

During the past 20 years, the need for improved efficiency in the collection of milk has resulted in 

the use of milk pumping equipment being installed on milk tankers. 

One of the most obvious places for a modern Dairy to optimize is the amount of time that the 

milk tanker uses to make a collection. If you can reduce the collection time at each farmer, the 

Dairy will be able to get a significant reduction in collection and transport cost for the benefit of 

the Farmer, Consumer and the Dairy itself. At the same time, you will get an environmental 

benefit as a result of reduced CO2 in the milk collection process. 

The consequence of introducing pump systems on milk tankers is that it causes air to be mixed 

with the milk which again will influence the accuracy of the magnetic flow-meter mounted in the 

system. Milk entrains air unlike petroleum liquids which do not. As you know, the flow meter 

will count anything that passes through the meter – liquid as well as air – and it is therefore 

essential that as much air as possible is removed from the milk before it reaches the flow-meter. 

However, it is widely recognized that it is not possible to remove all the air from the milk, which 

will result in an inaccuracy. 

It is therefore essential that the tolerances for vehicle mounted milk pump systems using magnetic 

flow-meters for determining milk volume reflects todays way of collecting milk. This means that 

existing Tolerance for milk meters cannot be used when the milk meter is a part of a system 

where different system parts will influence the accuracy of the count. Such milk metering systems 

will need to be classified with their own tolerances.

Based on our 25 years of experience as a manufacturer of these systems and more than 3000 

installations on milk trucks operating in more than 15 countries, we would like to propose that the 

Tolerance for Vehicle Mounted Milk Metering Systems is changed from 0.3 % to 0.5 % and that 

the tolerances will be listed and classified separately and not be associated with products from the 

oil industry. Our proposal is consistent with Weights & Measures tolerances accepted around the 

world.
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We hope that the NCWM will consider our proposal and we will be more than happy to meet 

with you and answer any questions you may have. We believe that a change of Tolerance is 

necessary in order for the Handbook 44 to reflect today ́s milk collection and the technical 

progress within milk collection.

Yours sincerely

Poul Tarp

President POUL TARP A/S 

The POUL TARP milk pump system holds an MID approval which is recognized and in accordance with 

guidelines and standards described in the OIML – International Organization of Legal Metrology

The standards related to metrological aspects come from OIML R117-1 for liquids (Dynamic measuring 

systems for liquids other than water, part 1: Metrological and technical requirements) and documents 

D11 (General requirements for electronic measuring instruments) and D31 (General requirements for

software-controlled measuring instruments) from OIML.

At the NCWM 2020 Interim Meeting, Carey McMahon (Poul Tarp) provided a presentation on their 

company’s VTM milk metering system advocating for expanding tolerances for these systems.
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Leigh Hamilton (Piper) provided a presentation concerning the piper system and stated in their 

presentation that Piper currently has an approved NTEP certificate for their device that is in service in the 

U.S. Leigh Hamilton opposed this item to increase the tolerances for milk meters and noted in their 

presentation that there may not be a need to increase the tolerances in order to move forward in allowing 

innovation in milk measurements. 

Charlie Stutesman provided a presentation on research that Kansas Department of Agriculture has done 

on the history of three NIST HB 44 Codes (3.31. VTMs, 3.35. Milk Meters, and 4.42. Farm Milk Tanks) 

and the issue of Piper’s NTEP Certificate. Charlie Stutesman discussed complications involved in 

measurement of product using various methods and potential shortcomings of Piper’s NTEP Certificate.

Doug Musick (Kansas) does not believe there is enough information presented to change existing 

tolerances and noted that the Piper system was only evaluated for accuracy up to a measurement of 300 

gallons. They also noted t that Piper’s certificate should be amended to qualify the system for draft sizes 

up to 300 gallons. Michael Keilty (Endress + Hauser) commented with concerns with Piper’s certificate. 

Leigh Hamilton noted that Piper followed and followed guidelines as provided during the NTEP 

evaluation. Diane Lee (NIST OWM) stated that the Committee may want to consider a Developing status 

for this item and that more information is needed concerning air elimination methods for milk metering 

systems.

A representative from the Dairy Farmers of America stated that they oppose the increase in tolerance but 

supports the use of VTM metering systems. Carey McMahon pointed out that the Poul Tarp system can 

be accurate for any size measurement, but the beginning and end of the measurement would not be 

accurate measures (within tolerance) due to entrained air in the product when the flow is not uniform. 

Dmitri Karimov (MMA) stated that the proposal should be further developed and pointed out that due to 

the tolerance structure becoming more stringent as the volume of the measurement increases, the 

acceptance tolerance at 500 gallons is unreasonable. Hal Prince (Florida) stated that he does not agree 

with expanding the tolerances. Hal Prince believes that air elimination should be the focus and that the 

proposal should be assigned to a task group. Tina Butcher (NIST OWM) noted that testing should be 

performed using multiple quantities and flowrates. Charlie Stutesman pointed out that confusion is 

generated by multiple HB 44 codes addressing the measurement of milk and that the proposal should be 

assigned to a TG to sort this out. Charlie Stutesman also pointed out there is no requirements in HB 44 

for air elimination pertaining to milk metering in these codes. Tina Butcher noted that the current HB 44 

requirements may not be flexible enough for this new technology and that the existing codes may need to 

be reviewed and updated.

Leigh Hamilton stated that this is not simply a consideration of only a change in tolerances. There are 

other requirements (currently in the OIML standard) that should also be considered in making any 

changes to the existing NIST HB 44 requirements. Michael Keilty stated that air elimination is a difficult 

problem to mitigate and noted that he is not sure if it is necessary to expand the existing tolerances or 

make other amendments. Carey McMahon stated that using the existing NIST HB 44 tolerances in the 

VTM Code, at a draft of 5000 gallons, the tolerance value is highly unreasonable. Charlie Stutesman 

noted that the type evaluation performed on the Piper system was limited to a draft of 300 gallons. If 

evaluation had included other draft sizes, the Piper system mat have failed the testing.

Ken Ramsburg (Maryland) stated that the proposal should be given a developing status. Ken Ramsburg 

agreed that there is no existing requirement for this type of system addressing air elimination and stated 

that the flow meter, air eliminator, plumbing, and pumps all need to be considered during evaluation and 

the evaluation should be conducted on the system. 
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Tim Chesser (Arkansas) questioned whether the flow meter used in the system is appropriate and noted 

that there are many unanswered questions surrounding this issue. Jim Willis (New York) recommended a 

Developing status for this item. Kevin Schnepp (California) stated that although they are opposed to 

relaxing existing tolerances, they supported the development of this proposal by an assigned Task Group.

During the Committee’s work session, the Committee agreed that this item has merit and should be given 

an Assigned status. The charge to the assigned task group will be to address three NIST HB 44 Codes 

(VTM, Farm Milk Tanks and Milk meters) to review the requirements and tolerances found in these 

codes and assess the need for changes.

The NCWM 2020 Annual Meeting, due to the 2020 COVID-19 pandemic, was adjourned to January 

2021, at which time it was held as a virtual meeting. Due to constraint of time, only those items 

designated as 2020 Voting Items were addressed. All other items were addressed in the subsequent 2021 

NCWM Interim Meeting.

At the 2021 NCWM Interim Meeting, the Committee heard from Charlie Stutesman who gave an update 

on the task group activities. Charlie Stutesman reported that the Milk Meter TG worked via e-mail 

communication and reviewed and discussed the proposed Milk Meter Tolerances in Agenda item VTM20.2. The Milk Meter TG also discussed the tolerances that are included in NIST HB 44 for Milk meters 

in various parts of HB 44 which include the VTM, Section 3.31, Farm Milk Tanks, Section 4.42., Mass 

Flow Meters, Section 3.37, and Milk Meters, Section 3.35. Charlie Stutesman also reported that the TG 

reviewed OIML tolerances for milk meters. They stated that after a review of the various tolerances, the 

Task Group agreed that the OIML tolerances provide tolerances that encompassed the system of 

measuring milk and not just a tolerance for the performance of the meter. The Milk Meter TG agreed 

with proposing the use of the OIML milk meter tolerance as the milk meter tolerances in the VTM code. 

Charlie Stutesman provided a copy of the proposed changes to VTM-20.2. The proposed tolerances will 

align the tolerances in the VTM Code for Milk Meters with OIML Milk Meter Tolerances. Charlie 

Stutesman requested that this item move forward as a Voting item. The Committee also heard from Clark 

Cooney (California) noted that he supported the items as Developing because one company mentioned 

meeting the existing tolerances. It was mentioned that the company’s testing was only performed over a 

limited range of volumes.

During the Committee’s work session, the Committee agreed with the proposal from the Milk Meter Task 

Group to adopt OIML tolerances for milk meters in the VTM code, that this item be given a Voting 

status, and that the Item Under Consideration be replaced with the work group’s proposal to adopt OIML 

tolerances. The Committee also agreed with expanding the Task Group to address other milk meter codes 

in HB 44. The Item Under Consideration above are the tolerances agreed to by the Milk Meter TG and 

that align with OIML tolerances. 

At the 2021 NCWM Annual Meeting, Charlie Stutesman provided an update on the Milk Meter Task 

Group activities. Charlie Stutesman noted that there was a field trip to observe milk metering systems. 

They noted that the proposed tolerances will align the milk tolerances with the OIML tolerances for milk 

meters and Charlie Stutesman noted that the OIML tolerances provides one tolerance for the meter and 

another tolerance for a milk metering system. They also noted that it may be impractical to perform an air 

eliminator test on these devices due to comingling of product. 

During the Committee’s work session, they agreed to a Voting Status for this item and added it to its 

voting consent calendar.
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During the Voting Session, Charlie Stutesman asked that consideration be given to adding a nonretroactive date to the proposed tolerances. It was questioned during the discussion that if a nonretroactive date was added to the tolerances, then, what tolerances would apply to existing meters that had 

been manufactured and tested prior to the non-retroactive date. One of the concerns expressed with 

having a new tolerance table without a nonretroactive date was whether or not existing devices would be 

required to be reevaluated in the NTEP. The conference voted against adding the nonretroactive 

requirement to the proposed tolerance table and the Item Under Consideration to change the tolerances 

failed to receive the 27 votes from the House of State Representatives, so the item failed and went back to 

the S&T Committee. The S&T Committee agreed to a Developing status for this item. 

Note: For reference, the Item Under Consideration that was included in the 2021 NCWM Interim 

Meeting Agenda is provided below: 

Table 2. Tolerances for Vehicle-Mounted Milk Meters

Indication

(gallons)

Maintenance Tolerance

(gallons)

Acceptance Tolerance

(gallons)

100 0.5 0.6 0.3 0.5

200 0.7 1.2 0.4 1.0

300 0.9 1.8 0.5 1.5

400 1.1 2.4 0.6 2.0

500 1.3 3.0 0.7 2.5

Over 500

Add 0.002 0.006

gallons per indicated 

gallon over 500 

Add 0.001 0.005 gallons 

per indicated gallon over 

500 

At the NCWM 2022 Interim Meeting, Charlie Stutesman (Chair of the Milk Meter TG) requested that this 

item be assigned back to the TG for further development. They provided an update on the TG meeting in 

January 2022 in which they discussed tolerances in both 3.31 Vehicle Tank Meters and 3.35 Milk Meters 

and the need to have the tolerance be applied to both vehicle mounted and station meters as the 

manufacturers are developing meters that will be capable of being installed in either application. The 

tolerance tables can be found in the supporting documents. Charlie Stutesman also renewed the TG’s

request to expand its scope to include possibly creating a new code that contains requirements of both 

vehicle mounted and stationary milk meters and metering systems due to the unique properties of milk as 

a liquid. Speaking on behalf of himself, Charlie Stutesman has provided a document in the supporting 

documents that outlines the four active and five inactive NTEP certified meters and metering systems in 

terms of test draft size and applicable tolerances. They noted that the active four have a range of 0.12 %

to 0.6 %. They noted that milk meters are the only liquid measuring device where the volume tolerance 

decreases as the draft size increases and suggests percentages more in line with OIML tolerance would be 

more appropriate. Ken Ramsburg suggested combining the two tolerances to be used for field 

evaluations. Diane Lee commented that the TG should work toward making all test methods uniform. 

Diane Lee also suggested that the TG and Committee look at the comments from various companies 

concerning different tolerance along the distribution line for milk. Doug Musick and Matt Douglas 

(California) supported assigning this item to the Task Group for further development. During Committee 

work sessions, the Committee agreed to assign this item back to the Milk Meter TG so they may continue 

to ascertain data. In addition, the Committee agreed to request that NCWM Chair Hankins expand the 

scope of the TG to include all reference to milk meters, meter systems and related test methods, 

specifications and tolerance in an effort to harmonize the codes. 
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The Committee agreed to an Assigned status for the item.

At the NCWM 2022 Annual Meeting, the Milk Meter TG Chair Stutesman, provided a status update the 

TG activities. They mentioned the TG continues to support proposed tolerances as provided in the Item 

Under Consideration. They also noted that the goal is consistency of the tolerances for milk meter 

measuring. TG Chair Stutesman also noted that another representative from the Western is need on the 

Milk Meter TG. 

At the Committee’s work session, the Committee agreed to keep an Assign status for this item.

At the 2023 NCWM Interim Meeting, Matt Curran (Florida), stated that it appears that this item is 

lowering the tolerance to get a device to fit and supports as voting if that is the case. Tina Butcher (NIST 

OWM) commented in support of an assigned status and that the application systems and meter needs 

clarification. The Committee decided to leave this item as an Assigned status and hopes a new TG group 

Chair steps forward.

Regional Association Reporting:

Western Weights and Measures Association

During the 2021 WWMA Annual Meeting, Diane Lee provided an update from the NCWM meeting. 

Diane Lee noted that the Milk Meter Task Group is still in the process of reviewing the item. The item 

was put forth for a vote at the NCWM but a last-minute change to make it non retroactive was made. 

Questions were raised as to what would happen to devices that are currently in the field? During the 

NCWM Annual Meeting this item was removed from the voting calendar and given a Developing status 

and NIST supported the Developing status. 

The WWMA S&T Committee recommended the status remain Developing. During the 2021 S&T Work 

Session Diane Lee was asked for further clarification on their testimony and provided the following 

clarification: “During the Annual Meeting a proposal was made to add a non-retroactive date. Because 

questions were raised as to how this would affect existing devices the item was moved from Voting to 

Developing.” The Committee looks forward to hearing from the WG.

During the WWMA 2022 Annual Meeting, the submitter was not present, and no comments were heard. 

During Open Hearings, due to timing constraints, the Committee did not take comments on Assigned 

Items. The Committee did allow the source to provide updates on these items. No update was provided. 

The WWMA S&T Committee recommended that this item remain Assigned. 

At the 2023 WWMA Annual Meeting, Aaron Yanker (Milk Meter Tolerance Task Group) updated the 

body, there is currently no Chairman of the Task Group and no updates provided.

The WWMA 2023 S&T Committee recommends this item remain Assigned to the NCWM Milk Meter 

Tolerance Task Group for further development and look forward to a Chair being assigned and an update 

provided. This Committee also recommends this item be blocked with MLK-23.2.
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Southern Weights and Measures Association

During the 2021 SWMA Annual Meeting Open Hearing no comments were received on this item. This 

Committee would like to see more evidence and reasoning on why these devices should not have to meet 

the existing tolerances, and why the tolerances listed are appropriate.

This Committee recommended the item remain Developing so that the submitters can gather more 

evidence about the accuracy of these devices. 

At the 2022 SWMA Annual Meeting, Matt Curran (Florida) stated they had concern about increasing the 

tolerance for new technology. No comments were received from the Milk Meter Tolerance Task Group. 

The SWMA S&T Committee recommended this item remain as an Assigned Item. 

Northeastern Weights and Measures Association

During the 2021 NCWM Interim Meeting Open Hearing the following comments were heard.

Jim Willis (New York) commented as a member of the TG about the field trip that was taken in Rochester 

New York just prior to the NCWM meeting in July to witness the truck mounted Milk Meters in action. 

The Task Group is asking for recommendations in regard to a tolerance value that people would be 

comfortable with. James Willis commented that the tolerance of 0.5 % is considered too large by some, 

but we have 0.4 % in the handbook now in-regards to checking a milk tank with a meter. 

Jimmy Cassidy (Massachusetts) asked if any systems currently meet the requirements in the handbook?

James Willis replied that currently there is one milk meter system on tank trucks that meets the 

requirements currently in the handbook. 

The NEWMA Specifications and Tolerances Committee recommended that this item remain in 

Developing Status.

During the 2022 NEWMA Annual Meeting Open Hearings, James Willis commented as a member of the 

Milk Meter TG and they indicated that the TG made strides and hopes for ability to perform additional 

work on the item.

After hearing comments from the floor, the Committee recognized the need for further development of the 

item and recommended that the item retain an Assigned status. The Committee recommended the NCWM 

Milk Meter TG continue to work with stakeholders to further develop this item.

During the 2022 NEWMA Interim Meeting, no comments were heard from the floor, however the 

Committee recommended that this item retain an Assigned status with the Milk Meter Tolerance Task 

Group. 

During the 2023 NEWMA Annual Meeting, James Willis stated that the Task Group does not have a 

Chair and no work on this item has not moved forward. He stated that he was in favor of this item at first 

as it would have relaxed the tolerances a little, but meters are now able to meet the tolerances that 

currently appear in the handbook. More data is needed from the system that is already type approved.

After hearing comments from the floor, the Committee recommended to the body that this item maintain

an Assigned status, and the body concurred.
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116

During the 2023 Interim Meeting the State of New Jersey stated that the Task Group still does not have a 

Chair, despite several requests from the NCWM S&T Committee, that manufacturers can meet the 

tolerances currently in the handbook, they recommended withdrawal. Massachusetts, Pennsylvania, and 

New York concur. Upon consensus of the body, the Committee recommends this item be Withdrawn.

Central Weights and Measures Association 

During the 2021 Interim Meeting Open Hearing, the Committee heard comments from the floor. Charles

Stutesman (Kansas) would like to see item be returned to Task Group.

CWMA S&T Committee recommended that the item be assigned to Milk Meter Tolerance Task Group 

and be an Assigned Item.

During the 2022 CWMA Annual Meeting Open Hearing, Charlie Stutesman remarked that following the 

2022 NCWM Interim Meeting, this item was sent back to the MMTTG. Moving forward with staying 

with original tolerances that were proposed. Request to expand scope has been submitted. There will be 

a MMTTG meeting prior to the July NCWM Annual Meeting. Hoping to move forward and elevate to 

Voting status for next cycle.

The CWMA S&T Committee recommended this item to remain an Assigned Item.

During the 2022 CWMA Interim Meeting, no comments were heard from the floor. 

The CWMA S&T Committee recommended this item to remain as Assigned status. 

During the 2023 CWMA Annual Meeting no comments were received. The CWMA S&T Committee 

recommends this item remain as Assigned to the Task Group. 

LPG – Liquified Petroleum Gas and Anhydrous Ammonia Liquid-Measuring 

Devices

LPG-23.1 I S.2.5. Zero-Set-Back Interlock

Source: National Propane Gas Association and U-Haul International

Submitter’s Purpose and Justification:

Address practical issues that propane retailers encounter when trying to comply with the zero setback 

requirements for propane stationary meters in Handbook 44.

This proposal reflects the intent of U-Haul International, Inc. and the National Propane Gas Association’s 

Technology, Standards and Safety Committee, a volunteer organization comprised of 2500+ members, 

including propane retail marketers and others providing products or services to the propane industry.

The intent behind enacting the current version of S.2.5.2 was to create consistency among motor-fuel 

devices used for all products. This proposal strikes a balance between a consistent standard for retail 

motor-fuel devices and the diverse applications and industry standard for dispensing LP-Gas. To that 

end, this proposal addresses only those devices used exclusively for retail motor-fuel transfer. Multi-use 
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LP-Gas devices that are used for the filling of motor-fuel and other containers, including grill cylinders, 

forklift cylinders, cylinders used on recreational vehicles and even motor fuel containers, are covered by 

S.2.5.1. 

Most LP-Gas dispensed is for purposes other than motor-fuel. (Less than 3 % of all LP-Gas used in the 

United States is used for transportation. See U.S. Department of Energy, Alternative Fuels Data Center 

https://afdc.energy.gov/fuels/propane_basics.html.) Pursuant to NFPA 58, this is accomplished by a 

trained and certified employee dispensing LP-Gas, typically using analog (mechanical) meters, into 

cylinders and tanks. The analog (mechanical) meters are safe and effective, and most notably exempt 

from the zero-set-back requirement because S.2.5.1 only applies to electronic devices. Clearly, Handbook 

44 recognizes this reality as S.2.5.1 does not require that all LP-Gas dispensers have zero-set-back 

interlocks, only electronic devices. S2.5.1 is most appropriate because currently there is no readily 

available technology that can be used to retrofit an analog device. When looked at from a cost/benefit 

perspective, one has to question the expense of replacing an analog device with an electronic device at a 

location that mostly serves portable cylinders and not motor vehicle tanks when LP-Gas’s use is so 

limited in transportation. 

Furthermore, NFPA 58 currently does not allow the public to refuel its LP-Gas powered motor vehicles. 

All motor vehicles or other containers must be filled by a specially trained employee. A proposed change 

has been introduced for consideration in the 2023 edition of NFPA 58 that would permit public refueling 

of motor vehicles as long as the dispensing system meets very specific safety requirements, including a 

specialized nozzle, and is furnished with visible instructions. Upon the acceptance of this new public 

refueling allowance, the LP-Gas industry agrees that Zero-Setback-interlocks are needed. These public 

self-service motor vehicle dispensing systems will be listed to Underwriters Laboratories Standard 495 

and will be dedicated to the filling of motor vehicles. 

For the minimal amount of retail motor fuel customers that a typical LP-Gas dispenser serves, both UHaul and NPGA feel that this proposal represents the most equitable approach to date for balancing the 

need to ensure fair transactions and consistent standards with how the LP-Gas industry currently 

dispenses LP-Gas and LP-Gas’s future transportation applications as envisioned by the proposed changes 

to NFPA 58 without conducting costly industry-wide retrofits of existing, functioning multi-use 

equipment. Handbook 44 needs to work with industry to make technical standards economically feasible 

lest it risk the advancement of LP-Gas as a viable and clean motor-fuel.

One continually occurring objection is that there would be no protection for the consumer without a zeroset-back feature on retail motor fuel devices. That really isn’t the case, however, as the customer always 

has the option to check the dispenser and meter before the filling process begins to verify that it is starting 

at zero.

The submitter requested that this be a Voting item.

NIST OWM Executive Summary for LPG-23.1 – S.2.5. Zero-Set-Back Interlock

NIST OWM Recommendation: Withdrawn 

• Zero set-back interlock ensures that a device is returned to zero before another customer or 

services person uses the device for another transaction thus preventing the facilitation of fraud 

per G-S.2. Facilitation of Fraud.
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NIST OWM Executive Summary for LPG-23.1 – S.2.5. Zero-Set-Back Interlock

• The LPG Code paragraphs S.2.5.1 and S.2.5.2 address electronic stationary and other 

stationary devices because the process for zero-set-back interlock operates differently for an 

electronic stationary device than it does for a stationary retail motor fuel device as described in 

S.2.5.2. but both devices are required to return to zero before another transaction is made.

• The submitter states that only a few transactions for LPG dispenser are for fueling vehicles and 

they are limited to use by trained staff. Paragraphs S.2.5.1 and S.2.5.2 are not dependent on 

who is dispensing the product or how often the device is used as a retail motor dispenser; the 

paragraphs are intended to ensure that the device is so designed that each new transaction starts 

at zero. What happens if they are used more frequently for use in fueling vehicles?

• According to the requirements both electronic stationary and stationary retail motor fuel 

dispensers must have a zero-setback interlock.

• If this proposal is adopted “Devices Used Exclusively as” would be added to both S.2.5.1. and 

S.2.5.2. to exempt stationary retail motor-fuel devices that are used for purposes other than 

dispensing retail motor-fuel from having a zero-set-back interlock and a note would be added 

to S.2.5.1. that would exempt Analog devices used for purposes other than dispensing retail 

motor-fuel from having a zero-set-back interlock. 

• Is this equitable to other products dispensed, such as gasoline or diesel. The devices that 

dispense these products are required to have a zero-setback interlock and are sometimes used 

to fill containers used for filling gasoline or diesel-powered equipment. Granted, the majority 

of these dispensers are used to fill vehicles; but does this create an unfair market situation 

where some fueling dispensers are required to have zero set-back interlock and others are not? 

• The submitter also stated that proposed changes were introduced for consideration in 2023 to 

allow public refueling of LP Gas with safety precautions and with these new requirements

zero-setback interlock is needed. How will LPG devices with and without zero-setback 

interlock be fairly- regulated? Is this equitable to other products dispensed, such as gasoline 

dispensers. Gasoline dispensers are required to have a zero-setback interlock, and some are 

used to fill containers used for gasoline- powered equipment. Granted, the majority of gasoline 

dispensers are used to fill vehicles; but does this create an unfair market situation where some 

fueling dispensers are required to have zero set-back interlock and others are not? 

• The submitter also stated that proposed changes were introduced for consideration in 2023 to 

allow public refueling of LP Gas with safety precautions and with these new requirements 

zero-setback interlock is needed. How will LPG devices with and without zero-setback 

interlock be fairly regulated? 

Table 2. Summary of Recommendations

LPG-23.1 – S.2.5. Zero-Set-Back Interlock

Status Recommendation Note* Comments

Submitter Voting

OWM Withdrawn
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WWMA Withdrawn

NEWMA Informational

SWMA Withdrawn

CWMA Withdrawn

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

Regulatory 1 California Dept. of Ag, Div. of Measurement Services

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Liquefied Petroleum Gas and Anhydrous Ammonia Liquid-Measuring Devices 

Code as follows:

S.2.5. Zero-Set-Back Interlock.

S.2.5.1. Zero-Set-Back Interlock, Electronic Stationary Meters (Other than Devices used 

Exclusively as Stationary Retail Motor-Fuel Dispensers) and Electronic Vehicle-Mounted 

Meters. − A device shall be constructed so that after an individual delivery or multiple deliveries 

at one location have been completed, an automatic interlock system shall engage to prevent a 

subsequent delivery until the indicating element and, if equipped, recording element have been 

returned to their zero positions.

[Nonretroactive as January 1, 2021]

(Added 2019) (Amended 2021 and 20XX)

Note: Devices used exclusively for Stationary Retail Motor-Fuel dispensing are those only utilizing a 

K15 connection on the hose-end valve, as required in NFPA 58 “Liquefied Petroleum Gas Code”. 

(Added 20XX)

S.2.5.2. Zero-Set-Back Interlock for Devices Used Exclusively as Stationary Retail MotorFuel Devices. – A device shall be constructed so that:

(a) after a delivery cycle has been completed by moving the starting lever to any position 

that shuts off the device, an automatic interlock prevents a subsequent delivery until the 
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indicating elements and recording elements, if the device is equipped and activated to 

record, have been returned to their zero positions;

(b) the discharge nozzle cannot be returned to its designed hanging position (that is, any 

position where the tip of the nozzle is placed in its designed receptacle and the lock can 

be inserted) until the starting lever is in its designed shut-off position and the zero-setback interlock has been engaged; and

(c) in a system with more than one dispenser supplied by a single pump, an effective 

automatic control valve in each dispenser prevents product from being delivered until the 

indicating elements on that dispenser are in a correct zero position.

[Nonretroactive as of January 1, 2017]

(Added 2016)

(Amended 20XX)

NIST OWM Detailed Technical Analysis: 

Zero set-back Interlock ensures that a device is returned to zero before another customer or services 

person uses the device for another transaction (to ensure that an automatic interlock prevents subsequent 

delivery until the indicating element is returned to zero). The LPG Code paragraphs S.2.5.1 and S.2.5.2 

address electronic stationary meters and other stationary retail motor-fuel devices because the process for 

zero-set-back interlock operates differently for an electronic stationary meter than stationary retail motorfuel devices as described in S.2.5.2. but both devices are required to return to zero before another 

transactions is made.

The submitter states that only a few transactions for LPG dispensers are for fueling vehicles and they are 

limited to use by trained staff. These paragraphs are not dependent on who is dispensing the product or 

how often the device is used as a retail motor dispenser; the paragraphs are intended to ensure that the 

device is so designed that each new transaction starts at zero. What happens if they are used more 

frequently for use in fueling vehicles?

According to the current requirements both electronic stationary and stationary retail motor fuel 

dispensers must have a zero-setback interlock. If this proposal is adopted “Devices Used Exclusively as” 

would be added to both S.2.5.1. and S.2.5.2. to exempt stationary retail motor-fuel devices that are used 

for purposes other than exclusively for the dispensing of retail motor-fuel from having a zero-set-back 

interlock and a note would be added to S.2.5.1. that would exempt Analog devices used for purposes 

other than exclusively for the dispensing of retail motor-fuel from having a zero-set-back interlock.

As such the zero-setback interlock requirement would only apply to those devices that are used 

exclusively to fuel vehicles. Is this equitable to other devices, such as gasoline dispensers. Gasoline 

dispensers are required to have a zero-setback interlock, and some are used to fill containers used for 

gasoline-powered equipment. Granted, the majority of gasoline dispensers are used to fill vehicles, but 

does this create an unfair market situation where some fueling dispensers are required to have zero setback interlock and others are not? 

The submitter also stated that proposed changes were introduced for consideration in 2023 to allow public 

refueling of LP Gas with safety precautions and with these new requirements zero setback interlock is 

needed. How will LPG devices with and without Zero-Setback Interlock be fairly regulated?
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NIST OWM believes additional discussion is needed concerning this item and how it will be enforced 

when other LPG devices are in use that require a zero-setback interlock and to also consider the impact of 

the proposed requirement on other retail motor fuel devices that dispense other products used to fuel 

vehicles.

Summary of Discussions and Actions:

During the 2023 NCWM Interim Meeting, Wes Strawn (Red Seal) submitted changes to the Committee 

to modify this item. The Committee agreed to add the following note to S.2.5.1.:

Note: Analog (Mechanical) devices used for multiple purposes other than exclusively for Retail 

Motor Fuel Dispensing are exempt. Any devices used exclusively for Stationary Retail Motor-Fuel 

dispensing are subject to S.2.5.2.

The Committee did not agree with striking “(Other than Stationary Retail Motor Fuel Dispensers)” from 

the title of S.2.5.1. and the title remains unchanged.

Scott Johnson (U-Haul International) recommends item move forward as voting. They supported the 

zero-set-back interlocks but not for dual-use meters (that don’t exclusively dispense vehicle fuel). Dmitri 

Karimov (Meter Manufacturers Association) supports the item with the changes submitted by Wes 

Strawn. Scott Simmons (Colorado Division of Oil and Public Safety) also supported the item with the 

changes submitted by Wes Strawn.

Kevin Schnepp (California Division of Measurement Standards) also supported the item with the changes 

submitted by Wes Strawn.

With the added note to S.2.5.1. the Committee believes this item is fully developed and assigned it a 

Voting status.

At the 2023 NCWM Annual Meeting, Konrad Pilatowicz (U-Haul International) explained that U-Haul 

submitted this item to create a balance and to have consistency among motor fuel dispensers. They feel 

the item makes sense and suggested it be made retroactive instead of non-retroactive.

Loren Minnich (NIST OWM) recommended downgrading to Informational status to allow additional 

discussion, if adopted would exempt any LPG RMFD not used exclusively for fueling vehicles, electronic

or analog, which may effectively exempt all LPG meters. In the justification the submitter states 

“existing dispenser systems... should be permitted to continue operations with the existing meter 

technology and should not be required to include Zero-Set-Back Interlocks. This should include when the 

dispenser is removed from one location and installed in another, as long as the original meter remains 

functional. This is a nonretroactive (NR) requirement, so it only applies to those devices manufactured 

after the NR date, new or used device brought into a state after the NR date, devices placed into 

commercial service after NR date (previously noncommercial), or devices going through the NTEP 

evaluation after NR date. Is this proposal equitable to RMFD that dispense other products? If the item 

remains voting OWM does not support its adoption.

Scott Johnson said U-Haul supports the proposed changes and has approximately 1200 locations that fill 

motor fuel and cylinders. They believe that at some point in the future, customers will be able to fill their 

own cylinders. Automotive applications are about 3 % of U-Haul’s business. Their opinion is the word 

“exclusive” suggests that it is a dedicated system. They also stated that the nozzles used do not allow 

cylinder to be filled.
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Stephen Benjamin (North Carolina) stated they are opposed to the item and agrees with NIST OWM that 

it should be downgraded to Informational status. They also stated that there are currently products on the 

market that can meet requirements. This is a carve out for a specific product and has not gone through the 

NTEP process. They agreed that the nozzle cannot be used to fill a cylinder currently but that could 

change in the future.

Matt Douglas (California Division of Measurement Standards) shares the concerns stated by NIST OWM 

and North Carolina.

Scott Simmons supports adoption, LPG is “clean” fuel and has infrastructure in place, NIST HB 44 

prohibits diversion of (measured) liquid, the devices that this requirement applies to is evident to 

inspectors.

Bruce Swiecicki (National Propane Gas Association) supports adoption. Konrad Pilatowicz will provide 

clarifying language to the committee. They are not aware of any instances of fraud and that this helps the 

industry move forward to support the use of alternative fuels.

Dmitri Karimov agrees with NIST OWM that the item should be downgraded to Informational status. 

Dmitri Karimov (representing Liquid Controls) understands issue and why U-Haul & NPGA have 

concerns.

Steve Timar (New York) echoes comments made by NIST OWM and supports moving to Informational 

status. 

Based on the comments heard during open hearings regarding the lack of clarity related to the phrase 

“Devices Used Exclusively as” and the application of this item if adopted, Bruce Swiecicki provided the 

Committee the following language and requested it replace the Note under S.2.5.1. in the item under 

consideration:

Note: Devices used exclusively for Stationary Retail Motor-Fuel dispensing are those only utilizing a 

K15 connection on the hose-end valve, as required in NFPA 58 “Liquefied Petroleum Gas Code”.

The Committee discussed this during the Committee work session and agreed to update the item with the 

new Note and retained the Voting status of the item. The item appeared in the Addendum as follows:

S.2.5. Zero-Set-Back Interlock.

S.2.5.1. Zero-Set-Back Interlock, Electronic Stationary Meters (Other than Devices used 

Exclusively as Stationary Retail Motor-Fuel Dispensers) and Electronic Vehicle-Mounted 

Meters. − A device shall be constructed so that after an individual delivery or multiple deliveries 

at one location have been completed, an automatic interlock system shall engage to prevent a 

subsequent delivery until the indicating element and, if equipped, recording element have been 

returned to their zero positions.

[Nonretroactive as January 1, 2021]

(Added 2019) (Amended 2021)

Note: Devices used exclusively for Stationary Retail Motor-Fuel dispensing are those only utilizing a 

K15 connection on the hose-end valve, as required in NFPA 58 “Liquefied Petroleum Gas Code”.

(Added 20XX)
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S.2.5.2. Zero-Set-Back Interlock for Devices Used Exclusively as Stationary Retail MotorFuel Devices. – A device shall be constructed so that:

(a) after a delivery cycle has been completed by moving the starting lever to any position 

that shuts off the device, an automatic interlock prevents a subsequent delivery until the 

indicating elements and recording elements, if the device is equipped and activated to 

record, have been returned to their zero positions;

(b) the discharge nozzle cannot be returned to its designed hanging position (that is, any 

position where the tip of the nozzle is placed in its designed receptacle and the lock can 

be inserted) until the starting lever is in its designed shut-off position and the zero-setback interlock has been engaged; and

(c) in a system with more than one dispenser supplied by a single pump, an effective 

automatic control valve in each dispenser prevents product from being delivered until the 

indicating elements on that dispenser are in a correct zero position.

[Nonretroactive as of January 1, 2017]

(Added 2016)

During the discussion of the item during the voting session, Matt Douglas stated that the item might be 

interpreted to either require the K15 connection for devices used to fuel vehicles or to only apply to 

devices that have the K15 connection. Matt requested that the status of the item be changed to 

Informational to allow further consideration.

Scott Simmons said he supported the item as presented.

Loren Minnich expressed appreciation for the additional clarification the note now provides but agreed 

with Matt Douglas that it would potentially limit the application of this paragraph to those devices with a 

K15 connection and not devices that are used to exclusively fuel vehicles. Because this could change 

both the application and scope of the paragraph, Loren also requested the status of the item be changed to 

Informational.

The Committee requested a short recess to confer and decided to change the status of the item to 

Informational.

Regional Association Reporting:

Western Weights and Measures Association

During the 2022 WWMA Annual Meeting, Konrad Philatowicz stated that Section 2.5.1 gives the general 

rule regarding the zero set back interlocks and that allows for manual and electronic meters to not meet 

the same standard which makes perfect sense. Section 2.5.2 refers to motor fuel dispensing devices and 

the word electronic is missing from the title. The changes address NIST and industry concerns and they 

asked that this be a Voting item at the NCWM Meeting. 

Scott Simmons was in support of this item for voting. 
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During open hearings, comments were heard supporting a Voting status. The WWMA S&T Committee 

believes that this item has merit, is fully developed, and recommended that this item be assigned a Voting 

status. 

At the 2023 WWMA Annual Meeting comments were heard from California, Colorado, and Oregon 

supporting a Withdraw of this item in lieu of LPG-24.1, LPG-24.2, and OTH 24.1.

The WWMA 2023 S&T Committee recommends this item be Withdrawn. 

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, no comments were received on this item. The SWMA S&T 

Committee recommended this item move forward as a Voting Item. 

At the 2023 SWMA Annual Meeting, Stephen Benjamin stated they opposed this item. The Committee 

recommends this Item be Withdrawn.

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting there were no comments heard from the floor. The Committee 

does not have a recommendation as to the status of this item. 

At the 2023 NEWMA Annual Meeting, Steve Timar opposed this item as it leaves the possibility of 

“hanging the nozzle”.

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

a Voting status with no changes, and the body concurred.

At the 2023 NEWMA Interim Meeting, Pennsylvania, Massachusetts, New York, and New Jersey 

recommend this item be informational. Upon consensus of the body, the Committee recommends this 

item be Informational. 

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, there were no comments were heard from the floor. 

The CWMA S&T Committee recommended this as a Developing Item. The Committee has concerns 

regarding a consumer/customer starting a delivery when the device is not on zero.

At the 2023 CWMA Annual Meeting, there were no comments received on this item. The CWMA S&T 

Committee believes this item is fully developed and recommends Voting status. 

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Withdrawn as we believe the attempted revision of this item was actually a resubmission listed under 

item LPG 24.2. The Committee recommends that the discussion history for this item be moved to LPG 

24.2. These recommendations are intended to clean up what we perceive to be an administrative error in 

that LPG 24.2 should not have been created but should have been an update to this item (LPG 23.1).
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LPG-24.1 S.1.5.7. Retail Motor Fuel Dispenser Liquefied Petroleum Gas Retail Motor 

Fuel Device., S.2.6.1. Electronic Stationary (Other than Stationary Retail 

Motor Fuel Dispensers Liquefied Petroleum Gas Retail Motor Fuel Device).

S.6.2. Automatic Timeout Pay-at-Pump Retail Motor Fuels Devices

Liquefied Petroleum Gas Retail Motor Fuel Device, and S.4.3. Location of 

Marking Information: Retail Motor Fuel Dispensers Liquefied Petroleum 

Gas Retail Motor Fuel Device.

Source: National Propane Gas Association

Submitter’s Purpose and Justification:

The proposal is a companion to the main proposal to modify 3.32, S.2.5.1 and S.2.5.2, and the proposal to 

change the definition of Liquefied Petroleum Gas Retail Motor-Fuel Device. The purpose of this proposal 

is to correlate the terminology in 3.32 for LP-gas and use only the defined term as proposed in the 

companion proposal.

Opposition would most likely come from those opposed to the primary changes in S.2.5.1 and S.2.5.2. 

Opposition may also come from those concerned about vehicles that do not have the K15 mating 

connection on the fill valve of the vehicle. Rebuttal to that would be that propane industry sources 

indicate that older vehicles that do not have the K15 connection are being retrofit at a high rate to 

incorporate the safety features of the K15 connection.

The submitter requested Voting status for these items in 2024.

NIST OWM Executive Summary for LPG-24.1 – S.1.5.7. Retail Motor Fuel Dispenser Liquefied 

Petroleum Gas Retail Motor Fuel Device., S.2.6.1. Electronic Stationary (Other than Stationary 

Retail Motor Fuel Dispensers Liquefied Petroleum Gas Retail Motor Fuel Device). S.6.2. 

Automatic Timeout Pay-at-Pump Retail Motor Fuels Devices Liquefied Petroleum Gas Retail 

Motor Fuel Device, and S.4.3. Location of Marking Information: Retail Motor Fuel Dispensers

Liquefied Petroleum Gas Retail Motor Fuel Device.

NIST OWM Recommendation: Withdraw

• The definition of “liquefied petroleum gas retail motor-fuel device” was added in 2022 for 

inclusion in the 2023 edition of NIST Handbook 44. Currently the definition recognizes the 

terms “retail motor-fuel dispenser” and “retail motor-fuel device” to be the same as and 

interchangeable with “liquefied petroleum gas retail motor-fuel device”.

• OTH-24.1. proposes amending this definition to apply only to those devices with a K15 nozzle. 

OWM does not support this change.

• If OTH-24.1 is withdrawn, OWM could support these proposed changes as it would replace 

various terms with one term that is defined and applies to this section of the handbook.

• This item should be blocked with LPG-24.2 and OTH-24.1 if they remain on the agenda.
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Table 2. Summary of Recommendations

LPG-24.1 – S.1.5.7. Retail Motor Fuel Dispenser Liquefied Petroleum Gas Retail Motor Fuel 

Device., S.2.6.1. Electronic Stationary (Other than Stationary Retail Motor Fuel Dispensers

Liquefied Petroleum Gas Retail Motor Fuel Device). S.6.2. Automatic Timeout Pay-at-Pump Retail 

Motor Fuels Devices Liquefied Petroleum Gas Retail Motor Fuel Device, and S.4.3. Location of 

Marking Information: Retail Motor Fuel Dispensers Liquefied Petroleum Gas Retail Motor Fuel 

Device.

Status Recommendation Note* Comments

Submitter Voting

OWM Withdrawn

WWMA Developing

NEWMA Developing

SWMA Developing

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44, Liquefied Petroleum Gas and Anhydrous Ammonia Liquid-Measuring Devices 

Code as follows:

S.1.5.7. Totalizers for Retail Motor-Fuel DispensersLiquefied petroleum gas retail motor-fuel 

device. – Retail motor-fuel dispensersLiquefied Petroleum Gas Retail Motor-Fuel Device shall 

be equipped with a nonresettable totalizer for the quantity delivered through the metering device. 

[Nonretroactive as of January 1, 2017] 

(Added 2016) (Amended 20XX)

S.2.6.1. Electronic Stationary (Other than Stationary Retail Motor-Fuel DispensersLiquefied 

Petroleum Gas Retail Motor-Fuel Device). – For individual deliveries, if there is no product 

flow for three minutes the transaction must be completed before additional product flow is 

allowed. The three-minute timeout shall be a sealable feature on an indicator. 
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[Nonretroactive as of January 1, 2021] 

(Added 2021) (Amended 20XX)

S.2.6.2. Automatic Timeout Pay-at-Pump Retail Motor-Fuel DevicesLiquefied Petroleum 

Gas Retail Motor-Fuel Device – Once a device has been authorized, it must deauthorize within 

three minutes if not activated. Reauthorization of the device must be performed before any 

product can be dispensed. If the time limit to deauthorize the device is programmable, it shall not 

accept an entry greater than three minutes.

[Nonretroactive as of January 1, 2022] 

(Added 2021) (Amended 20XX)

S.4.3. Location of Marking Information; Retail Motor-Fuel DispensersLiquefied Petroleum 

Gas Retail Motor-Fuel Device. – The marking information required in General Code, paragraph GS.1. Identification shall appear as follows: 

(a) within 60 cm (24 in) to 150 cm (60 in) from the base of the dispenser; 

(b) either internally and/or externally provided the information is permanent and easily read; 

and 

(c) on a portion of the device that cannot be readily removed or interchanged (i.e., not on a 

service access panel). 

The use of a dispenser key or tool to access internal marking information is permitted for retail 

motor-fuel dispensers liquefied petroleum gas retail motor-fuel device. 

[Nonretroactive as of January 1, 2003] 

(Added 2006) (Amended 20XX)

NIST OWM Detailed Technical Analysis: 

NIST OWM did not provide a detailed analysis for this item.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, Greg VanderPlaats (Minnesota) asked if LPG 23.1 needs to pass 

before this item can be considered. The Committee recommends this item as a Voting item blocked with 

item OTH 24.1.

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting comments were heard on LPG-24.1, LPG-24.2, and OTH-24.1 

collectively. There was consensus of support for the items and a request to Block the three items. There 

were comments that this may be an opportunity to clarify existing language in HB 44 which some find 
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confusing, and possibly merging S.2.5.1 and S.2.5.2. A question was also posed to the body to address 

the intent of the item by exempting analog devices from a Zero Set Back Interlock requirement.

Based on the comments heard during the open hearings the WWMA S&T Committee recommends this 

item be Blocked with LPG-24.2 and OTH-24.1 and that the Blocked items be assigned a Developing 

status to allow the body an opportunity to review the new language and allow the submitter to address the 

comments heard during open hearings.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Steve Benjamin (North Carolina) stated they see this item as 

cleanup and that a follow up item will be needed next year.

The Committee recommends blocking this item with LPG-24.2 and OTH-24.1.

The Committee recommends this item move forward as a Developing item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, New York opposes this item and does not see the need for the 

changes. Upon consensus of the body, the Committee recommends this item be Developing.

LPG-24.2 S.2.5. Zero-Set-Back Interlock. S.2.5. Zero-Set-Back Interlock.

Source: National Propane Gas Association

Submitter’s Purpose and Justification:

The proposal will address practical issues that propane retailers encounter when trying to comply with the 

zero setback requirements for propane stationary meters in Handbook 44.

This proposal reflects the intent of U-Haul International, Inc. and the National Propane Gas Association’s 

Technology, Standards and Safety Committee, a volunteer organization comprised of 2500+ members, 

including propane retail marketers and others providing products or services to the propane industry.

The intent behind enacting the current version of S.2.5.2 was to create consistency among motor-fuel 

devices used for all products. This proposal strikes a balance between a consistent standard for retail 

motor-fuel devices and the diverse applications and industry standard for dispensing LP-Gas. To that 

end, this proposal addresses only those devices used exclusively for retail motor-fuel transfer. Multi-use 

LP-Gas devices that are used for the filling motor-fuel and other containers, including grill cylinders, 

forklift cylinders, cylinders used on recreational vehicles and even motor fuel containers, are covered by 

S.2.5.1. 

Most LP-Gas dispensed is for purposes other than motor-fuel. (Less than 3% of all LP-Gas used in the 

United States is used for transportation. See U.S. Department of Energy, Alternative Fuels Data Center 

afdc.energy.gov/fuels/propane_basics.html.) Pursuant to NFPA 58, this is accomplished by a trained and 

certified employee dispensing LP-Gas, typically using analog (mechanical) meters, into cylinders and 

tanks. The analog (mechanical) meters are safe and effective, and most notably exempt from the zero-setback requirement because S.2.5.1 only applies to electronic devices. Clearly, Handbook 44 recognizes 
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this reality as S.2.5.1 does not require that all LP-Gas dispensers have zero-set-back interlocks, only 

electronic devices. S2.5.1 is most appropriate because currently there is no readily available technology 

that can be used to retrofit an analog device. When looked at from a cost/benefit perspective, one has to 

question the expense of replacing an analog device with an electronic device at a location that mostly 

serves portable cylinders and not motor vehicle tanks when LP-Gas’s use is so limited in transportation. 

Furthermore, NFPA 58 currently does not allow the public to refuel its LP-Gas powered motor vehicles. 

All motor vehicles or other containers must be filled by a specially trained employee. A proposed change 

has been introduced for consideration in the 2023 edition of NFPA 58 that would permit public refueling 

of motor vehicles as long as the dispensing system meets very specific safety requirements, including a 

specialized nozzle, and is furnished with visible instructions. Upon the acceptance of this new public 

refueling allowance, the LP-Gas industry agrees that Zero-Setback-interlocks are needed. This public, 

self-service motor vehicle dispensing systems will be listed to Underwriters Laboratories Standard 495 

and will be dedicated to the filling of motor vehicles. 

For the minimal amount of retail motor fuel customers that a typical LP-Gas dispenser serves, both UHaul and NPGA feel that this proposal represents the most equitable approach to date for balancing the 

need to ensure fair transactions and consistent standards with how the LP-Gas industry currently

dispenses LP-Gas and LP-Gas’s future transportation applications as envisioned by the proposed changes 

to NFPA 58 without conducting costly industry-wide retrofits of existing, functioning multi-use 

equipment. Handbook 44 needs to work with industry to make technical standards economically feasible 

lest it risk the advancement of LP-Gas as a viable and clean motor-fuel. 

At its August 2022 meeting, the Central Weights and Measures Association recommended LPG-23.1 as a 

Developing Item with the following comment: “The Committee has concerns regarding a 

consumer/customer starting a deliver when the device is not on zero.” In response, there are two points to 

make regarding the transfer of liquid propane into a container. The first is that any transfer made into 

cylinders (not mounted on vehicles) would have to be done by propane service personnel. The customer 

would not be permitted to transfer product into any cylinder, even if they own that container.

Secondly, LPG-23.1 is intending to clarify that dispensers which are used exclusively for retail motor fuel

will be subject to the zero setback requirements. It is only these dispensers, which are installed at public 

retail motor vehicle refueling stations, that are permitted to be operated by the general public to refuel 

vehicles. Therefore, because of the zero setback and time-out provisions in Handbook 44, there really is 

no opportunity for the customer to “game” the dispenser system.

NIST OWM Executive Summary for LPG-24.2 – S.2.5. Zero-Set-Back Interlock. S.2.5. Zero-SetBack Interlock

NIST OWM Recommendation: Withdrawn/Developing

• If the item remains as proposed it should be withdrawn or be assigned a developing status.

• OTH-24.1. proposes amending the definition of “liquefied petroleum gas retail motor-fuel 

device” to apply only to those devices with a K15 nozzle. OWM does not support this change 

until the K15 connector is the standard for all LPG powered vehicles.

• This item should be blocked with LPG-24.1 & OTH-24.1 if they remain on the agenda.
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NIST OWM Executive Summary for LPG-24.2 – S.2.5. Zero-Set-Back Interlock. S.2.5. Zero-SetBack Interlock

• S.2.5. (later amended and renumbered as S.2.5.2.) was adopted as a nonretroactive requirement 

taking into consideration that the devices in service prior to adoption could not meet this 

requirement.

• In the justification of this item the submitter asserts that “costly industry-wide retrofits of 

existing, functioning multi-use equipment” are required. S.2.5.1. and S.2.5.2. were adopted as 

a nonretroactive requirements to prevent this. 

• The weights & measures community should carefully consider the impact of making S.2.5.1. 

retroactive as it was adopted in 2019 with an effective date of January 1, 2021. There may be 

devices that cannot comply with this requirement which would need to be retrofitted if this 

item is adopted as proposed.

• A search of the NCWM website indicates that there are various retail motor-fuel devices 

designed to dispense LPG that have an NTEP CC. Those installed after 1/1/2017 are required 

to have a zero-set-back interlock.

• Zero set-back interlock prevents the facilitation of fraud in accordance with G-S.2. Facilitation 

of Fraud by ensuring a dispenser returns to zero before the next transaction can be initiated 

whether the transaction is initiated by trained service personnel or a customer filling their own 

vehicle.

• In the justification for OTH-24.1. the submitter acknowledges that not all propane powered 

vehicles have the K15 connection. Per the U.S. Department of Energy’s website “The National 

Fire Protection Association (NFPA) Code 58 (beginning with the 2017 version) requires all 

new vehicles to be equipped with the quick-release “Type K15” connector as of January 1, 

2020. The ACME QCC screw-on connector has been used since 1994 for both vehicles and 

bottle filling.”

• Those vehicles that have the older style connection may have no choice but to fill at a station 

that may not have a device that has a zero-setback interlock.

Table 2. Summary of Recommendations

LPG-24.2 – S.2.5. Zero-Set-Back Interlock. S.2.5. Zero-Set-Back Interlock

Status Recommendation Note* Comments

Submitter No status specified by submitter

OWM Withdrawn

WWMA Developing

NEWMA Developing

SWMA Developing

CWMA Voting

NCWM
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Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association 1 NPGA (submitter)

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44, Liquefied Petroleum Gas and Anhydrous Ammonia Liquid-Measuring Devices 

Code as follows:

S.2.5. Zero-Set-Back Interlock. 

S.2.5.1. Zero-Set-Back Interlock, Electronic Stationary Meters (Other than Stationary Retail 

Motor- Fuel Dispensers Liquefied Petroleum Gas Retail Motor-Fuel Device) and Electronic 

Vehicle-Mounted Meters. − A device shall be constructed so that after an individual delivery or 

multiple deliveries at one location have been completed, an automatic interlock system shall 

engage to prevent a subsequent delivery until the indicating element and, if equipped, 

recording element have been returned to their zero positions. 

[Nonretroactive as January 1, 2021]

S.2.5.2. Zero-Set-Back Interlock for Stationary Retail Motor-Fuel Devices Liquefied 

Petroleum Gas Retail Motor-Fuel Device. – A device shall be constructed so that:

(a) after a delivery cycle has been completed by moving the starting lever to any position 

that shuts off the device, an automatic interlock prevents a subsequent delivery until 

the indicating elements and recording elements, if the device is equipped and activated 

to record, have been returned to their zero positions;

(b) the discharge nozzle cannot be returned to its designed hanging position (that is, any 

position where the tip of the nozzle is placed in its designed receptacle and the lock can 

be inserted) until the starting lever is in its designed shut-off position and the zero-setback interlock has been engaged; and

(c) in a system with more than one dispenser supplied by a single pump, an effective 

automatic control valve in each dispenser prevents product from being delivered until 

the indicating elements on that dispenser are in a correct zero position.

[Nonretroactive as of January 1, 2017]
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S.2.5. Zero-Set-Back Interlock

S.2.5.1 Zero-Set-Back Interlock, Electronic Stationary Meters (Other than Stationary 

Retail Motor- Fuel Dispensers Liquefied Petroleum Gas Retail Motor-Fuel Device) and 

Electronic Vehicle-Mounted Meters. A device shall be constructed so that after an 

individual delivery or multiple deliveries at one location have been completed, an automatic 

interlock system shall engage to prevent a subsequent delivery until the indicating element 

and, if equipped, recording element have been returned to their zero positions.

S.2.5.2. Zero-Set-Back Interlock for Stationary Retail Motor-Fuel Devices Liquefied 

Petroleum Gas Retail Motor-Fuel Device. – A device shall be constructed so that:

(a) after a delivery cycle has been completed by moving the starting lever to any 

position that shuts off the device, an automatic interlock prevents a subsequent 

delivery until the indicating elements and recording elements, if the device is 

equipped and activated to record, have been returned to their zero positions;

(b) the discharge nozzle cannot be returned to its designed hanging position (that is, 

any position where the tip of the nozzle is placed in its designed receptacle and the 

lock can be inserted) until the starting lever is in its designed shut-off position and 

the zero-set-back interlock has been engaged; and

(c) in a system with more than one dispenser supplied by a single pump, an effective 

automatic control valve in each dispenser prevents product from being delivered 

until the indicating elements on that dispenser are in a correct zero position.

NIST OWM Detailed Technical Analysis: 

Both S.2.5.1. and S.2.5.2. were adopted as nonretroactive requirements. Per G-A.6. these paragraphs are 

only applicable to devices that are:

(a) manufactured within a state after the effective date;

(b) both new and used, brought into a state after the effective date;

(c) used in noncommercial applications which are placed into commercial use after the effective 

date; and

(d) undergoing type evaluation, including devices that have been modified to the extent that a new 

NTEP Certificate of Conformance (CC) is required.

In the Introduction to NIST Handbook 44, Section E. Classification of Requirements. It is stated that “The 

classification of requirements into “retroactive” and “nonretroactive” status is made in order that the 

requirements may be put into force and effect without unnecessary hardship and without wholesale 

condemnation of apparatus...Nonretroactive requirements are those that, while clearly desirable, are not 

so vital that they should at once be enforced with respect to all apparatus.”

Any LPG dispensing device that was in commercial service prior to January 1, 2017, whether analog, 

digital, mechanical, or electric, is not required to have a zero-setback interlock whether it is used to fill 
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tanks, cylinders or vehicles. Analog devices used to only fill cylinders or tanks are not required to have a 

zero set-back interlock as these specifications are not applicable to these devices. The assertion by the 

submitter that “costly industry-wide retrofits of existing, functioning multi-use equipment” are required is 

inaccurate.

Those stationary devices placed into commercial service after January 1, 2017, which are used to dispense 

LPG into vehicles (retail motor-fuel devices) are required to have a zero set-back interlock. Stationary 

meters and vehicle tank meters that are electronic and were placed in service after January 1, 2021, are 

required to have a zero set-back interlock no matter the application. The weights & measures community 

should carefully consider the impact of making S.2.5.1. as there may be devices that cannot comply with 

this requirement which would need to be retrofitted if this item is adopted as proposed.

This item is directly affected by the change proposed to the definition of liquefied petroleum gas retail 

motor-fuel device. OWM does not support limiting this definition to apply only to devices with a K15 

nozzle. While LPG powered vehicles manufactured after January 1, 2020 are required to have the “Type 

K15” connector it is not required on all LPG powered vehicles. Adoption of this item along with OTH24.1. would create an inequitable situation for owners of LPG powered vehicles. Those without a K15 

connector would be unable to use those devices with the K15 nozzle to fuel their vehicles which would be 

the only devices required to have a zero set-back interlock. Until the K15 connector is required on all 

LPG powered vehicles OWM cannot support this proposed change.

Zero set-back interlock ensures that a device is returned to zero before the next transaction is initiated. 

This feature is required on other retail devices including liquid measuring devices, mass flow meters, 

hydrogen measuring devices, and electric vehicle supply equipment. This would include devices that 

dispense kerosene which is not considered a fuel typically suitable for vehicles and is used in ways 

similar to LPG such as heating and cooking.

This is a new item on the S&T agenda. No prior discussion has occurred.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, Greg VanderPlaats (Minnesota) asked if there is a concern with 

one of the LPG items passing and not the others. Should they be blocked together? The Committee 

recommends this item as a voting item.

The Committee believes that this item is an attempted revision of item LPG 23.1 and should not have 

been submitted. Now that this item has been submitted, the committee recommends that the discussion 

history for LPG 23.1 be moved to LPG 24.2. These recommendations are intended to clean up what we 

perceive to be an administrative error in that LPG 24.2 should not have been created but should have been 

an update to item LPG 23.1.
NIST OWM Analysis

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Western Weights and Measures Association

During the WWMA 2023 Annual Meeting, comments were heard on LPG-24.1, LPG-24.2, and OTH24.1 collectively.

There was consensus of support for the items and a request to Block the three items. There were 

comments that this may be an opportunity to clarify existing language in HB 44 which some find 

confusing, and possibly merging S.2.5.1 and S.2.5.2. A question was also posed to the body to address 

the intent of the item by exempting analog devices from a Zero Set Back Interlock requirement.

Based on the comments heard during the open hearings the WWMA S&T Committee recommends this 

item be Blocked with LPG-24.1 and OTH-24.1 and that the Blocked items be assigned a Developing 

status to allow the body an opportunity to review the new language and allow the submitter to address the 

comments heard during open hearings.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Steven Benjamin, North Carolina, asked the Committee to doublecheck the language used in the agenda because he believed it to be incorrect. The Committee found that 

the language format was incorrect compared to the language used in the Form 15. The Committee has 

decided to consider the language and formatting used in the items Form 15. 

This language is as follows:

S.2.5. Zero-Set-Back Interlock.

S.2.5.1. Zero-Set-Back Interlock, Electronic Stationary Meters (Other than Stationary Retail 

Motor- Fuel Dispensers Liquefied Petroleum Gas Retail Motor-Fuel Device) and Electronic 

Vehicle-Mounted Meters. − A device shall be constructed so that after an individual delivery or 

multiple deliveries at one location have been completed, an automatic interlock system shall 

engage to prevent a subsequent delivery until the indicating element and, if equipped, recording 

element have been returned to their zero positions.

[Nonretroactive as January 1, 2021]

S.2.5.2. Zero-Set-Back Interlock for Stationary Retail Motor-Fuel Devices Liquefied 

Petroleum Gas Retail Motor-Fuel Device. – A device shall be constructed so that:

(a) after a delivery cycle has been completed by moving the starting lever to any position 

that shuts off the device, an automatic interlock prevents a subsequent delivery until the 

indicating elements and recording elements, if the device is equipped and activated to 

record, have been returned to their zero positions;

(b) the discharge nozzle cannot be returned to its designed hanging position (that is, any 

position where the tip of the nozzle is placed in its designed receptacle and the lock can 

be inserted) until the starting lever is in its designed shut-off position and the zero-setback interlock has been engaged; and

(c) in a system with more than one dispenser supplied by a single pump, an effective 

automatic control valve in each dispenser prevents product from being delivered until the 
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135

indicating elements on that dispenser are in a correct zero position.

[Nonretroactive as of January 1, 2017]

The Committee recommends this item move forward as a Developing item, with the language and 

formatting used in the Form 15 and suggests blocking the item with LPG-24.1 and OTH-24.1.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, the State of New York opposes this item and does not see the need 

for the changes, the new wording is no longer in italics and questions if the submitters are suggesting it be 

retroactive as it is not stated in justification. It was pointed out that this item is similar to LPG-23.1 but 

does not include U-Haul and the National Propane Gas Association requested withdrawal of LPG-23.1 in 

this proposal. Upon consensus of the body, the Committee recommends this item be Developing.

MLK – MILK METERS

MLK-23.2 A Table T.1. Tolerances for Milk Meters

Source: Milk Meter Tolerances Task Group

Submitter’s Purpose and Justification:

Eliminate the current tolerance structure of a decreasing permissible tolerance allowance as the size of the 

test draft increases.

This is a companion item to VTM-20.2 [Vehicle Mounted Milk Meters] currently being considered. It 

would be logical to block these two items as the data and discussion for changes to both Handbook 44 

sections will be identical. This proposal is being made to eliminate the current tolerance structure of a 

decreasing permissible tolerance allowance as the size of the test draft increases. The proposed changes 

are identical to the current tolerance structure in the international community that follow OIML R-117. 

Without the changes to the tolerances, it would be possible for a device to be within tolerance at small test 

drafts and be out of tolerance for larger test drafts that are more representative of a typical delivery.

If OIML tolerances are adopted, the tolerances that are currently in place may increase at larger test 

drafts.

The Submitter requested a Voting status for this Item.

NIST OWM Executive Summary for MLK-23.2 – Table T.1. Tolerances for Milk Meters

NIST OWM Recommendation: A review of this item by the Milk Meter Task Group will be useful. 

We agree with the regions that recommended this item remain Assigned to the Milk Meter Task Group, 

and when the task group meets the item should be fully vetted by industry and the weights and measures 

community. 

• The Milk Meter Task Group reviewed all the varying tolerances in NIST HB 44 for Milk meters. 

Instead of keeping a decreasing tolerance as the test draft increases, the Task Group is proposing 
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NIST OWM Executive Summary for MLK-23.2 – Table T.1. Tolerances for Milk Meters

that the tolerances, as included in the 2024 Interim Meeting Agenda for VTM-20.2 for milk 

meters, also be adopted in the Milk Meter code. 

• Aaron Yanker (Colorado) is listed on the NCWM website as the Milk Meter Task Group Chair 

When the Task Group meets, a review of the item to include a review from affected industry and 

weights and measures jurisdictions is recommended.

• NIST OWM recognizes the comment made by the submitter to consider blocking item MLK23.1 with VTM-20.2 and a comment to withdraw item MLK-23.1. VTM-20.2 was discussed by

the Milk Meter Task Group which included comments from industry and weights and measures 

jurisdictions and also appeared as a voting item on the S&T agenda. If the items are combined, a 

recommendation to withdrawn MLK-23.2 may affect VTM-20.2. 

Table 2. Summary of Recommendations

MLK-23.2 – Table T.1. Tolerances for Milk Meters

Status Recommendation Note* Comments

Submitter Voting

OWM Assigned

WWMA Assigned

NEWMA Withdrawn

SWMA Assigned

CWMA Assigned

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Milk Meters Code, as follows:
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T.2. Tolerance Values. – Tolerances shall be as shown in Table 1. Tolerances for Milk Meters.

(Amended 1989 and 20XX)

Table 1. Tolerances for Milk Meters

Indication

(gallons)

Maintenance Tolerance

(gallons)

Acceptance Tolerance

(gallons)

100 0.5 0.3

200 0.7 0.4

300 0.9 0.5

400 1.1 0.6

500 1.3 0.7

Over 500 Add 0.002 gallon per indicated 

gallon over 500

Add 0.001 gallon per indicated gallon 

over 500

(Added 1989)

Table 1. Tolerances for Milk Meters

Acceptance Tolerance Maintenance Tolerance

Complete Measuring 

System 0.5 % 0.5 %

Meter Only 0.3 % 0.3 %

(Amended 20XX)

NIST OWM Detailed Technical Analysis: 

The Milk Meter Task Group reviewed all the varying tolerances in NIST HB 44 for Milk Meters. Instead 

of keeping a Milk Meters code that is decreasing in tolerance as the test draft increases, the Task Group is 

proposing that the tolerances as included in the 2024 Interim Meeting Agenda for VTM-20.2 Milk Meter 

also be adopted in the Milk Meter code. 

In accordance with the NCWM website Aaron Yanker (Colorado) is listed as the Milk Meter Task Group 

Chair. The Task Group should review the proposed changes to the tolerances to ensure full vetting by 

industry and the weights and measures community. 

Regional Association Reporting:

Western Weights and Measures Association

During the WWMA 2022 Annual Meeting, Michael Keilty (Endress+Hauser) alerted the Committee that 

the TG Chair no longer works for the State of Kansas, leaving a vacancy for the Chair position. Matt

Douglas (California Division of Measurement Standards) recommended that this be combined with 

VTM-20.2 and recommended assignment to the Milk Meter Tolerance Task Group. In the original 

justification, the submitter recommended that this item be blocked with VTM-20.2. The WWMA S&T 

Committee recommended that this item be assigned to the Milk Meter Tolerance Task Group and that this 

item be blocked with VTM-20.2. 
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Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Matt Curran (Florida) stated that he opposed raising the tolerances 

to accommodate this new device. No comments were received from the Milk Meter Tolerance Task 

Group. 

The SWMA S&T Committee recommended this item be Assigned to the Milk Meter Tolerance Task 

Group. 

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting, no comments were heard from the floor. The Committee does 

not have a recommendation as to the status of this item.

At the 2023 NEWMA Annual Meeting, Jim Willis (New York) stated the Task Group does not have a 

Chair and no work on this item has not moved forward. 

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

an assigned status, and the body concurred.

At the 2023 NEWMA Interim Meeting, the State of New Jersey stated that the Task Group still does not 

have a chair, despite several requests from the NCWM S&T Committee, that manufacturers can meet the 

tolerances currently in the handbook and recommends withdrawal. The Commonwealths of 

Massachusetts and Pennsylvania, and the State of New York concur. Upon consensus of the body, the 

Committee recommends this item be Withdrawn.

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, Doug Musick (Kansas) stated the current tolerance table has a 

specified tolerance for a specified draft size. The percentage calculations for them do not match. The 

percentage tolerance changes for the same meter based on draft size. Updating the tolerance will make it 

uniform with other liquid tolerance tables.

Michael Keilty (Endress+Hauser) stated that the sizes of provers for this testing are not common. They 

are difficult to find. 

The CWMA S&T Committee believes this item is fully developed and recommends Voting status.

At the 2023 CWMA Annual Meeting no comments were received. The CWMA S&T Committee 

recommends this item remain as Assigned to the Task Group.
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HGM – Hydrogen Gas-Measuring Devices

HGM-23.1 D UR.3.8. Safety Requirement

Source: Quong and Associates, Inc.

Submitter’s Purpose and Justification: 

Add safety requirement for hydrogen gas measuring devices. The proper fueling of hydrogen vehicles is 

critical to ensure that the vehicle and high-pressure tank is not damaged. Unlike other gases, such as 

compressed natural gas, hydrogen heats as a vehicle is fueled due to the reverse Joule-Thompson effect.

This means that the fueling rate and temperature of the hydrogen must be carefully controlled, or damage 

can occur to the vehicle hydrogen tanks. The hydrogen industry has done considerable work in

developing standard fueling protocols in SAE.

J2601 (https://www.sae.org/standards/content/j2601_202005/) and validation methods in 

ANSI/CSA HGV 4.3

(https://www.csagroup.org/store/product/CSA%25100ANSI%20HGV%204.3%3A22/) to ensure 

that the vehicles are fueledcorrectly and safely.

The validation of SAE J2601 using ANSI/CSA HGV 4.3 has been performed on the 50+ hydrogen

stations in California bythe Air Resources Board (ARB) 

(https://ww2.arb.ca.gov/resources/documents/annual-hydrogen-evaluation.) The proposed

requirement provides assurances that dispensers have been verified to the proper fueling protocol 

which will protect the dispenser, vehicle, and consumer.

While the California Department of Food and Agriculture is discussing submitting the same language for 

the California Code of Regulations, adding the same language of Handbook 44 would allow other states 

to understand and adopt the key hydrogenfueling protocol standards, thereby expanding the use of

hydrogen throughout the United States.

The submitter acknowledged that some may argue that the equipment to validate stations is not available

except in California.

The submitter’s response would be that, first, there are other private companies who have the equipment

to test dispensers outside of California, includingstations in the northeast US. Second, HGV 4.3 allows 

for factory acceptance testing of dispensers prior to installation and an abbreviated Site Acceptance Test.

This approach shortens the time and equipment necessary to verify a station meets SAE J2601. Third, the 

design and software of the Hydrogen Station Equipment Performance (HyStEP) Device used byARB is

publicly available. (https://h2tools.org/hystep-hydrogen-station-equipment-performance-device)

The submitter provided the following links: 

• SAE J2601: https://www.sae.org/standards/content/j2601_202005/ (copyrighted)

• ANSI/CSA HGV 4.3 

(https://www.csagroup.org/store/product/CSA%25100ANSI%20HGV%204.3%3A22/)

(copyrighted)
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• California Air Resources Board: Annual Evaluation of Fuel Cell Electric Vehicle Deployment &

Hydrogen Fuel StationNetwork Development

• https://ww2.arb.ca.gov/resources/documents/annual-hydrogen-evaluation (many reports

available, latest is too large to attach)

• EVSE Pre_Rule Wkshop Shared Deck.pdf

The submitter requested that this be a Voting Item in 2023.

NIST OWM Executive Summary for NIST HGM-23.1 – UR.3.8. Safety Requirement

NIST OWM Recommendation: OWM has no recommendation until additional data is submitted.

• It has not been part of the weights and measures standards development process to include 

prescriptive safety requirements into handbook legal metrology standards.

• The dispenser’s design features regardless of their function should not affect the metrological 

integrity of the equipment.

• Traditional fueling applications have established mechanisms to address the safety features of 

dispenser installations not typically within the scope of the weights and measures authority.

• Groundwork is not outlined in the proposal detailing key elements that must be established for 

an SAE J2601 verification program and what standards if any apply to equipment in operation 

before the effective date.

• NIST OWM looks forward to the reporting from CA DMS and CARB as well as any updates 

from the submitter to clarify the types of test data available that are the result of compliance 

testing to the SAE J2601 standard. 

Table 2. Summary of Recommendations

HGM-23.1 – UR.3.8. Safety Requirement

Status Recommendation Note* Comments

Submitter Voting

OWM 5

More information requested on the impact on 

dispenser performance and required 

investment outlay for the proposed test 

WWMA Voting

NEWMA Withdrawn

SWMA Developing

CWMA Withdraw

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments
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Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44 Hydrogen Gas-Metering Devices Code as follows:

UR 3.8. Safety Requirement –All hydrogen gas-measuring devices subject to this code shall 

maintain verification of testingdemonstrating conformance with the latest version of SAE J2601

Fuel Protocols for Light Duty Gaseous Hydrogen SurfaceVehicles, as determined by the latest 

version of ANSI/CSA HGV 4.3 “Test Methods for Hydrogen Fueling Parameter Evaluation.”

[Nonretroactive as of January 1, 20XX]

(Added 20XX)

NIST OWM Detailed Technical Analysis: 

NIST OWM looks forward to the reporting from CA DMS and CARB as well as any updates from the 

submitter to clarify the types of test data available that are the result of compliance testing to the SAE 

J2601 standard. Also of interest are the logistics and other background information on the testing 

program. On initial consideration this proposal appears to require weights and measures officials to 

assess compliance with an SAE and ANSI standards. The official will be required to verify the owner is 

operating dispensing equipment that holds fueling safety protocol certification to SAE J2601 which can 

involve the performance of the dispenser, its programing, communications capability, and the station’s 

hydrogen storage system as well as a suitable test apparatus for use in the verification procedure. It has 

not been part of the weights and measures standards development process to include prescriptive safety 

requirements into handbook legal metrology standards. The dispenser’s design features regardless of 

their function should not affect the metrological integrity of the equipment.

If it is just an inspection for possession of current documentation, that may be more palatable; however, 

that is not really clear from the proposal and weights and measures programs do not typically enforce 

safety standards. Will compliance with safety standards keep coming up as an issue with alternative fuel 

dispensing systems used in vehicle refueling applications? This is unlike traditional fueling applications 

which have established mechanisms to address the safety features of dispenser installations. How does 

each jurisdiction ensure that equipment has met safety standards without putting weights and measures 

programs in the position of having to verify the equipment complies with standards other than HB 44, 

since that’s not typically within the scope of their authority (other than a limited number of programs 

which do regulate safety requirements)? 
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Safety is always the first priority; however, has the groundwork been laid to provide all the key 

components to weights and measures jurisdictions to properly address existing and new installations of 

equipment. The safety community should be approached on lessons learned in similar applications and to 

determine all other options and possible opportunities to make stakeholders in the up-and-coming 

hydrogen marketplace aware of recommended practices for safe fueling protocols. 

Summary of Discussions and Action:

At the 2023 NCWM Interim Meeting, Kevin Schnepp (California Division of Measurement Standards) 

stated California has 68 stations that all require this standard and 33 private stations that do not have this 

requirement that facilitates accurate and safe fueling. Supports item. Kevin Schnepp response to Matt

Curran’s (Florida) comment, “it’s a performance protocol as well, not just for safety”.

Spencer Quong gave a presentation during open hearings. Heat generated from filling can cause damage. 

This is important to protect the consumer. Requests informational status, so the proposal can be 

continued to be developed.

Tina Butcher (NIST OWM) stated, typically NIST Handbook 44 does not include safety requirements. 

That generally rests with non-Weights and Measures agencies. They do not question the need but do 

question if NIST Handbook 44 is the right place for this. Matt Curran echoed Tina Butcher’s comments.

The Committee would like to see the metrological effect this has on the device. The Committee decided 

to keep this proposal as developing.

Regional Association Reporting:

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, there were no comments from the floor. The CWMA S&T 

Committee recommended this proposal as a Developing Item. Clarification regarding the term 

“verification” is needed.

At the 2023 CWMA Annual Meeting, there were no comments. The CWMA S&T Committee restated its 

earlier recommendation for clarifying the term “verification” and that this item remain Developing.

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

be Withdrawn. The Committee questions the merit of this information being provided in Handbook 44 

and have not received answers to questions outlined in the historical comments for this item.

Western Weights and Measures Association

During the WWMA 2022 Annual Meeting the following comments were received:

Kevin Schnepp has worked with the submitter and SAE J 2601 is a requirement for operating in the state 

of California. This is a safety protocol. This is both a standard and a test method. The design parameters 

for the equipment meet the standard. This is not a type evaluation requirement; it is a user requirement. 

They supported this item.

The WWMA S&T Committee feels that this item has merit and recommended that this item be assigned a 

Developing status with consideration to the concerns identified during open hearings.
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During the WWMA 2023 Annual Meeting, Kevin Schnepp (stated that data is being collected by CDFA 

DMS and CARB. Kevin Schnepp requested that this item remain developing until the data can be 

provided.

The WWMA 2023 S&T Committee recommends this item remain Developing based on comments heard 

to allow the submitter the ability to provide data and address the concerns in comments from the 2023 

WWMA S&T Committee and 2023 NCWM S&T Committee. This Committee considered the comments 

recorded in the 2023 NCWM S&T Committee Interim Meeting Report in their analysis and echoes the 

concerns raised in the report on how this protocol affects performance is addition to safety.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Matt Curran questioned whether this was the proper venue for this 

item. Paul Floyd (Louisiana) also commented that this was not the proper venue for this item. This 

Committee would like the NCWM S&T Committee to consider whether this type of item is within the 

scope of weights and measures. 

The SWMA S&T Committee recommended this item move forward as a Developing Item.

At the 2023 SWMA Annual Meeting, Dr. Curran questioned if this is the proper venue for the safety 

requirements but supports safety concerns in the item.

The Committee recommends this item remains as a Developing item to allow time for the data to be 

collected.

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting, Spencer Quong (submitter and representing Toyota Motors North 

America) explained the requirements for validation of fueling protocol through SAE. Spencer Quong 

indicated that if hydrogen vehicles filled too quickly, it will overheat and if the fueling protocol is 

performed significantly different, it may affect accuracy. Juana Williams (NIST OWM) noted that safety 

is first and foremost however, this proposal would require that the owner of the device be trained in 

fueling safety, which is not typical to put in HB44. Jason Flint (New Jersey) commented that the 

language in this item may be more suited for other standard setting organizations such as NFPA.

After hearing comments from the floor, the Committee recommended that this item be given a 

Developing status.

At the 2023 NEWMA Annual Meeting, the Committee heard no comments on this item but 

recommended to the body that this item retain Developing status and the body concurred.

At the 2023 NEWMA Interim Meeting comments were heard that no additional data has been provided as 

to what the effects on the metrological parameters are. New York, New Jersey, and Holliston, 

Massachusetts recommended withdrawal.

Upon consensus of the body, the Committee recommends this item be Withdrawn.
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EVF – Electric Vehicle Fueling Systems

EVF-24.1 S.1.3. Mobile Device as Indicating Element for AC Chargers.

Source: Siemens Industry Inc.’s Smart Infrastructure eMobility

Submitter’s Purpose and Justification:

Clarify that use of a hand-held mobile device such as a mobile phone to provide the Indicating Elements 

for an EVSE is an acceptable alternative to having the Indicating Elements built into the EVSE. This 

option is already accepted by the National Type Evaluation Program for certification.

Most AC chargers installed today for public charging do not have electronic displays. The requirements 

for showing prices, quantity delivered, cost of delivery, and other required data elements of Section 3.40 

are fulfilled by displaying the data on a mobile phone or within the vehicle receiving the electrical energy. 

This alternative to having a display on the charger itself reduces the cost of the charger, as well as 

maintenance required when displays fail due to harsh outdoor conditions, including direct sunlight and 

wind, rain, and snow exposure. These conditions often make the built-in displays difficult to read. 

Having the option of providing the display on a mobile device or in the vehicle reduces costs, improves 

EVSE longevity, and, most importantly, improves the consumer experience. Moreover, EV drivers 

usually utilize their mobile phones to carry out charging transactions already, so the drivers are 

accustomed to receiving the information on their device or in their vehicle. Finally, the industry is 

moving toward Plug and Charge, based on the ISO 15118 Road Vehicles – Vehicle to Grid 

Communication Interface standard. With Plug and Charge, the vehicle communicates with the charger to 

authenticate as well as initiate and end charging, with the fees processed automatically. With Plug and 

Charge, there is no interaction between the driver and the charger. ISO 15118 is a requirement for federal 

funding under the National Electric Vehicle Infrastructure (NEVI) Formula Program and the Charging 

and Fueling Infrastructure Discretionary Grant (CFI) Program, as well as for some state funding, 

including in California.

The opposing arguments would be that there are, in fact, some AC chargers that have the Indication of 

Delivery on their face – but these are limited and much more expensive.

The submitter requested that this have Voting status in 2024 as a retroactive specification.

NIST OWM Executive Summary for EVF-24.1 – S.1.3. Mobile Device as Indicating Element for AC 

Chargers

NIST OWM Recommendation: Withdraw. The EVSE primary display must meet a more 

comprehensive set of requirements in multiple codes to provide clear, legible, and verifiable 

transaction information and other metrological data in an appropriate manner. 

• NIST OWM does not believe the proposed exceptions are appropriate without more detailed 

work to fully vet the permissible metrological features and functions for the wide range of 

software based remote devices to be recognized as the primary indicating elements for these 

commercial electrical energy measuring systems.

• The list of requirements referenced in the proposal (S.1.1., S.1.2., S.2.4.1, S.2.6, S.2.7, 

UR.1.1., and UR.3.1.) is not all inclusive of the paragraphs in NIST HB 44 applicable to 
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NIST OWM Executive Summary for EVF-24.1 – S.1.3. Mobile Device as Indicating Element for AC 

Chargers

indicating elements. There are additional requirements in Sections 1.10. General Code, 3.40.

Electric Vehicle Fueling Systems and 5.55 Timing Devices that apply to an EVSE display that 

is an integral part of the electrical energy dispensing system or when a single display is used by 

multiple EVSEs. Therefore, additional accompanying requirements need to be developed for 

clarity and to fully recognize the proposed options for primary displays.

• It was suggested prior to the code’s adoption in 2016, to identify those paragraphs which are 

posing difficulties for some manufacturers to meet and possibly making those paragraphs nonretroactive, with an eventual sunset date, rather than proposing an exception to the entire code.

• Likewise, OWM also suggested that exceptions are sometimes made for certain applications 

which are able to meet a requirement in a different way through other mechanisms such as a 

contract or other price agreement or fleet sales.

• An additional concern, with regard to equity, is that companies have spent money to comply 

with display requirements and after 2024 would be competing with a population of existing 

noncompliant equipment and new equipment which will not have to be equipped in the same 

manner with a primary display.

• The proposal is unclear if the devices running those apps are a necessity for the operation of 

the charging equipment although the proposal specifies the location of the handheld device or 

vehicle as “being in the immediate vicinity of the EVSE” and yet there is no mention of their 

availability over the entire course of the transaction given a session can take twenty minutes or 

multiple hours to complete.

• The open-ended nature of the types of devices that fall under this category means a wide 

variety of handheld devices or vehicles would be part of the type evaluation process where 

their accuracy and clarity become more critical to the measurement transaction.

• If they are the only EVSE primary display these newly recognized devices will be the means 

for accessing the device/system metrological security information which can be sizable, and 

determining fuel quantity totals.

• With some further work “Apps” installed on a mobile device might provide the best 

opportunity for allowing for innovation since there is a mechanism for reviewing the display 

provided by the app and ensuring its operation provides the necessary information. 

• The vehicle user interface, on the other hand, is somewhat problematic. They can vary from 

manufacturer to manufacturer and will undoubtedly change from year to year. How will the 

operator or regulatory official verify transaction information if vehicle user interface is the 

only means available for verification of this information? Will drivers be asked to voluntarily 

assist in inspections and complaint investigations, or will a car be provided as part of the 

official’s tool kit? The code will need to address this, and it will be necessary to ensure type 

evaluation can adequately address this. 

• How would the overall provisions of the General Code regarding legibility, clarity, and 

appropriateness of indications be applied when there is no display unique to a given EVSE on-
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NIST OWM Executive Summary for EVF-24.1 – S.1.3. Mobile Device as Indicating Element for AC 

Chargers

site? The code addresses the EVSE as the intended point at which commercial measurements 

of electrical energy and related time fees are being made rather than the handheld device or 

EV. 

• Will there be unique or common vulnerabilities to factors such as levels of service, 

temperature, connectivity, etc. For traditional vehicle fuel dispensers and other alternative 

vehicle fuel dispensers weather and normal wear issues are managed through equipment and 

station design and maintenance programs.

• The submitter cites the concept of “Plug and Charge” that is part of ISO 15118 but has not 

provided information on the exact relevance/application to legal metrology requirements that 

apply. 

• Currently EVF-24.1 is a proposal for a new requirement but the letter-number paragraph 

designation of S.1.3. is already part of the existing code and is titled EVSE Units. Does the 

submitter intend the proposal to replace existing code; be part of indicating element 

requirements already included in the code; or have a new letter-number designation?

Table 2. Summary of Recommendations

EVF-24.1 – S.1.3. Mobile Device as Indicating Element for AC Chargers.

Status Recommendation Note* Comments

Submitter Voting

OWM Withdraw Expand to fully address all other 

interconnected display requirements 

WWMA Developing

NEWMA Developing

SWMA Withdrawn

CWMA Developing

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda
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5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44, Electric Vehicle Fueling Systems as follows:

S.1.3. Mobile Device as Indicating Element for AC Chargers. – the indication requirements 

and elements specified in Section 3.40, sub-sections S.1.1., S.1.2., S.2.4.1, S.2.6, S.2.7, UR.1.1., 

and UR.3.1. may be fulfilled through either a display built into the EVSE or a display available 

via an application on a hand-held device such as a smart phone or in the purchaser’s vehicle 

receiving the electrical energy, such device or vehicle being in the immediate vicinity of the 

EVSE.

(Added 20XX)

NIST OWM Detailed Technical Analysis: 

NIST OWM does not believe the proposed exceptions are appropriate without more detailed work to fully 

vet the permissible metrological features and functions for the wide range of software based remote 

devices to be recognized as the primary indicating elements for these commercial electrical energy 

measuring systems. The proposal lists five design requirements and two requirements the operator of the 

EVSE currently must meet for the display (indicating element) to function properly and to provide sales 

transaction and power level information at specific points during the transaction for an electrical energy 

charging session. Given some categories of these handheld/vehicle devices will be running other apps, 

vehicle information, etc. whereas currently commercial measuring equipment was required to maintain 

weights and measures functions and information separate from other programs running or stored on the 

device/system. This list of requirements is not all inclusive of the NIST HB 44 Section 1.10 General 

Code and remaining Section 3.40 EVSE code requirements that currently make up the minimum 

handbook requirements for an EVSE display when an integral part of the electrical energy dispensing 

system or single display used by multiple EVSEs. Those code paragraphs required to be met in the 

proposal do not encompass the entire range of display capability and features assessed during type 

evaluation based on the General Code nor the 5.55 Timing Devices Code for EVSEs that assess fees for 

time related services that are associated with electrical energy charging sessions. Therefore, additional 

accompanying requirements need to be developed for clarity and to fully recognize the proposed options 

for primary displays. The proposal would make it permissible for a software application when in use on 

either a handheld device or in the vehicle refueling with electrical energy in proximity to the EVSE to be 

used to meet seven requirements for display and or recording as well as computing specific transaction 

information.

Handheld devices and vehicle displays would currently be recognized as supplemental ways of displaying 

transaction information but not as the primary display. Agenda Item EVF-24.1 is a new 2024 proposal 

which if adopted by the July 2024 NCWM would from that point onward be enforceable for all AC EVSE 

systems regardless of when they were manufactured or placed into commercial use. Handheld devices 

and vehicle displays would be recognized for use to a limited degree as primary displays for AC EVSEs. 

It was suggested several times to the Subgroup that developed the EVSE code requirements when the 

code was first proposed for adoption in 2016, to identify those paragraphs which are posing difficulties to 

some manufacturers to meet and proposing they be made non-retroactive, with an eventual sunset date 

rather than proposing an exception to the entire code. Likewise, OWM also suggested that exceptions are 

sometimes made for certain applications which are able to meet a requirement in a different way through 

other mechanisms such as a contract or other price agreement or fleet sales. An additional concern is that 
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companies spent money to comply with display requirements and after 2024 would be competing with a 

population of existing noncompliant equipment and new equipment which will not have to be equipped in 

the same manner with a primary display.

The proposal is unclear if the devices running those apps are a necessity for the operation of the 

equipment although the proposal specifies the location of the handheld/vehicle device “being in the 

immediate vicinity of the EVSE” and yet there is no mention of their availability over the entire course of 

the transaction given a session can take twenty minutes or multiple hours to complete.

The concept of recognizing a remote type of indicating element other than a display that is either an 

integral part of the dispenser or is part of system and used to provide information for multiple EVSEs has 

been discussed but not as part of national discussions. Currently, the proposal presents a short list of 

remote devices, but might this proposal be an opening for much broader interpretation on what constitutes 

a handheld device. The open-ended nature of the types of devices that fall under this category means a 

wide variety of handheld devices would be part of the type evaluation process where their accuracy and 

clarity become more critical to the measurement transaction. If they are the only EVSE primary display 

these newly recognized devices will be the means for accessing the device/system metrological security 

information which can be sizable and determining fuel quantity totals. 

With some further work “Apps” installed on a mobile device might provide the best opportunity for 

allowing for innovation since there is a mechanism for reviewing the display provided by the app and 

ensuring its operation provides the necessary information. The vehicle user interface, on the other hand, 

is somewhat problematic. They can vary from manufacturer to manufacturer and will undoubtedly 

change from year to year. They are not included in type evaluations nor are they realistic for regulatory 

officials to control to ensure clarity, accuracy, and transparency in the measurement transaction. If a user 

interface is to be used as a primary display (rather than simply an additional display), the code will need 

to address this, and it will be necessary to ensure type evaluation can adequately address this. How will 

the visibility and clarity of the primary display be verified since this can vary from vehicle manufacturer 

to vehicle manufacturer? The vehicle interface should not be provided as an option to satisfy the 

requirements for the primary display. How would the overall provisions of the General Code regarding 

legibility, clarity, appropriateness of indications be applied when there is no display unique to a given 

EVSE on-site? The code addresses the EVSE as the intended point at which commercial measurements 

of electrical energy and related time fees are being made rather than the handheld device or EV. 

The device codes are developed with the equipment manufacturer, regulatory official, customer, and 

seller in mind. How will the operator or regulatory official verify transaction information if vehicle user 

interface is the only means available for verification of this information? Will drivers be asked to 

voluntarily assist in inspections and complaint investigations, or will a car be provided as part of the 

official’s tool kit? In some respects, the indicating element is no longer in the possession of the 

owner/operator of the device.

Will there be unique or common vulnerabilities to factors such as levels of service, temperature, 

connectivity, etc. It should be noted that other alternative vehicle fuel dispensers provide a primary 

display which are maintained under weather conditions and normal wear. For traditional fuel and 

alternative fuel dispensers weather issues are managed through equipment and station design and 

maintenance programs. EVSEs have moved from home charging into the marketplace where there may 

not be a station attendant on duty during all operating hours to address environment and wear on 

frequently used parts of the system. The submitter cites an international standard which introduced the 

concept of “Plug and Charge” that is not in effect nationally, as part of the justification for recognizing 

handheld/vehicle devices with apps as the primary display for EVSEs but has not provided information on 
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the exact relevance/application of ISO 15118 to legal metrology requirements that apply. The submitter 

has provided no details on the standard’s effect on how the regulatory official and manufacturer will 

determine, based on compliance with this international standard, the electric vehicle fueling system’s 

compliance to requirements in the General Code, EVFS, and Timing Devices Codes. 

Currently EVF-24.1 is a proposal for a new requirement but the letter-number paragraph designation of 

S.1.3. is already part of the existing code and is titled EVSE Units. Does the submitter intend the 

proposal to replace existing code; be part of indicating element requirements already included in the code; 

or have a new letter-number designation?

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Developing and seeks input from industry stakeholders.

During the WWMA 2023 Annual Meeting, general comments were heard on the floor from Chris King 

(Siemens), Francesca Wahl (Tesla), Kevin Schnepp (CA Division of Measurement Standards), Jose 

Arriaga (Orange County Agriculture Weights and Measures, CA), Mike Brooks (Arizona Department of 

Agriculture Weights and Measures Services Division), Brent Ricks (Montana Department of Labor and 

Industry) supporting Developing status for this item. 

Francesca Wahl stated that Tesla is already using a display in vehicle not one located on the charger and 

these systems hold a California Type Evaluation Program Certificate for these chargers. Comments were 

also heard on the floor regarding from three regulatory official indicating concern with this item, in 

particular: 

- Accessibility of the mobile device by the consumer (credit card payment vs. mobile payment 

app). 

- Use and responsibility of the device indication by consumer. 

- Code should apply to DC as well as AC chargers. 

- Code should only apply to those devices which require a mobile app to activate. 

- Addressing potential wireless connection issues that may occur. 

In response to an inquiry about the type of technology being used to connect the indication to the charger, 

Chris King indicated RFID and Bluetooth are used by these devices to identify the user. Francesca Wahl 

noted that in European regulation there must be encryption on the backend that requires a key to link 

them. 

The WWMA S&T Committee recommends that this item be assigned a Developing status to allow the 

submitter the opportunity to consider the comments heard on the floor and receive feedback from 

stakeholders. 
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Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Tim Chesser (Arkansas) recommended the item be withdrawn 

because they were not going to enforce indicating element requirements on cell phones of customers.

Dr. Matt Curran (Florida) echoed those same comments and raised concern about privacy with the use of 

customers’ cell phones.

Patrick Bean (Tesla) stated their devices rely on customer phones and vehicle indicators for customer user 

interface. They also stated DC Chargers should be included with the item.

John Stokes (South Carolina) was not in support of this item.

The Committee has reservations about having the customer cell phone as the sole indicating element for 

these devices.

The Committee recommends the item be Withdrawn.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, a written statement from Siemens was provided and read during 

the comment period, which is included on the NCWM website. A regulator from Holliston, 

Massachusetts commented that when the Method of Sale was approved for EV, it was specified that there 

be physical displays on the devices and what is being recommended is highly appropriate. A regulator 

from the Commonwealth of Pennsylvania questioned what ramifications would this cause for other 

display requirements across the board (e.g., gasoline)? Other devices have proved they can have 

markings on displays in all kinds of weather and doesn’t agree with the proposal. The States of Vermont, 

New Hampshire, New Jersey, New York, and Massachusetts agree with Pennsylvania that the display 

must appear on the device. Upon consensus of the body, the Committee recommends this item be 

Developing.

EVF-24.2 S.2.7. Indication of Delivery, N.3.2. Accuracy Testing, and T.2.1. EVSE Load 

Test Differences Tolerances.

Source: California Department of Food and Agriculture, Division of Measurement 

Standards

Submitter’s Purpose and Justification: 

Change the exemption period for DC EVFS from 2028 to 2025.

The 2028 exemption was provided for DC EVFS due to the lack of available field test equipment that 

could accurately test and verify conformance of DC EVFS to established tolerances. Testing equipment 

capable of testing DC EVFS at the higher power levels of modern DC EVFS is now available and new 

manufactures of test equipment are entering the market now. The justification for the exemption for DC 

EVFS is no longer valid as regulating jurisdictions have access to test equipment that can properly 

evaluate installations of DC EVFS for conformance to the adopted specifications and tolerances. The 

availability of DC EVFS test equipment has been verified by two test equipment manufacturers and by 

research conducted by Argonne National Lab. With fully capable test equipment available in 2023 and 
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151

2024, establishing a 2025 effective is reasonable and provides a uniform, transparent, and equitable 

marketplace for both consumers and competing businesses. 

T.2.1. Does not have any separate specifications for either AC or DC EVFS. It is intended to be 

applicable to all EVFS.

EVFS manufacturers and regulators agreed to a 2028 date due to lack of available testing equipment. 

During open hearings prior to adoption of the 2028 exemption date, industry representatives agreed that 

the 2028 could be amended once test equipment was available.

The submitter requested that this have Voting status in 2024 as nonretroactive provisions.

NIST OWM Executive Summary for EVF–24.2 – S.2.7. Indication of Delivery, N.3.2. Accuracy 

Testing, and T.2.1. EVSE Load Test Differences Tolerances

NIST OWM Recommendation: Voting to allow fundamental requirements such as accuracy to be 

met uniformly across the marketplace.

• The proposal modifies the 2028 enforcement date to become 2025 for DC Systems (1)

automatic display of the start at zero and the final quantity of the electrical energy delivery, (2)

performance test procedures, and (3) associated test tolerances.

• The 2028 enforcement dates were adopted July 2022 as part of an emergency agenda item to 

make the NIST HB 44 EVFS Code permanent and in response to a lack of test equipment.

• The lack of access until 2028 to fundamental requirements, such as these for indications, 

accuracy tests, and tolerances, might possibly lead to nonuniformity in the application of those 

three sections of the EVFS code.

• Paragraph G-A.3. Special and Unclassified Equipment exists for use by jurisdictions wishing 

to inspect and test existing equipment in order to approve it for commercial use.

• We recognize that commercially available testing devices for high powered chargers are slated 

to become more widely available shortly and essential to verify DC fast charging equipment.

• The Committee should correct the letter number designation for the test note to become N.3.2. 

not N.5.2. and the title of the tolerance requirement to become T.2.1. EVSE Load Test 

Tolerances not EVSE Load Test Differences. Should the submitter further modify the proposal 

to make the requirements enforceable to equipment only after the effective date, then the text 

should be changed to italic type.
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Table 2. Summary of Recommendations

EVF–24.2 – S.2.7. Indication of Delivery, N.3.2. Accuracy Testing, and T.2.1. EVSE Load Test 

Differences Tolerances

Status Recommendation Note* Comments

Submitter Voting

OWM Voting

WWMA Voting

NEWMA Voting

SWMA Voting

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44 Electric Vehicle Fueling Systems Code as follows:

S.2.7. Indication of Delivery. – The EVSE shall automatically show on its face the initial zero 

condition and the quantity delivered (up to the capacity of the indicating elements).

All DC EVSE are exempt from this requirement until January 1, 20282025.

(Amended 2022 and 20XX)

And 

N.5.2. Accuracy Testing. – The testing methodology compares the total energy delivered in a transaction 

and the total cost charged as displayed/reported by the EVSE with that measured by the measurement 

standard.

(a) For AC systems:
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(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a total 

energy delivered of at least twice the minimum measured quantity (MMQ). If the MDA 

would result in maximum deliverable power of greater than 7.2 kW, then the test may be 

performed at 7.2 kW.

(2) Accuracy test of the EVSE system at a load of not greater than 10 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a total 

energy delivered of at least the minimum measured quantity (MMQ).

(a) For DC systems (see note):

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes current (expressed as MDA) as determined from the digital 

communication message from the DC EVSE to the test standard for a total energy 

delivered of at least twice the minimum measured quantity (MMQ).

(2) Accuracy test of the EVSE system at a load of not more than 10 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the digital communication 

message from the DC EVSE to the test standard for a total energy delivered of at least the 

minimum measured quantity (MMQ).

All DC EVSE are exempt from this requirement until January, 20282025.

(Amended 2022 and 2025)

And

T.2.1. EVSE Load Test Tolerances. – The tolerances for EVSE load tests are:

(a) Acceptance Tolerance: 1.0 %; and 

(b) Maintenance Tolerance: 2.0 %.

All DC EVSE are exempt from this requirement until January 1, 20282025.

(Amended 2022 and 2025)

NIST OWM Detailed Technical Analysis: 

The code requirements under consideration in this proposal are exempted from enforcement until 2028 

and apply to the automatic display of the start at zero and the final quantity of electrical energy delivered 

by a DC EVSE and performance test procedures and the associated test tolerances applicable to DC 

systems. The current three requirements addressed in the proposal were the only parts of Section 3.40 

EVFS Code adopted in July 2022 to become a permanent code with an effective date of January 1, 2028. 

This occurred as part of a late June 2022 weights and measures regulators’ proposal assigned emergency 

status for upgrading the tentative NIST HB 44 EVSE code from trial and experimental status (held since 

July 2015) to become permanent and enforceable in 2023 for all commercial EVSEs. This action was 

also due in part to 2022 concerns about the available supply of adequate DC EVSE test equipment.
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The lack of access until 2028 to fundamental requirements, such as these for indications, accuracy tests, 

and tolerances, might possibly lead to nonuniformity in the application of those three sections of the 

EVSE code. There is a willingness to consider making specific portions of the code nonretroactive in 

order to allow some industry to bring their equipment into compliance, but typically this is not the case 

for accuracy requirements. As an additional general comment, OWM notes that the NIST Handbook 44 

General Code will continue to apply to existing equipment, including paragraph G-A.3. Special and 

Unclassified Equipment. Jurisdictions wishing to inspect and test existing equipment in order to approve 

it for commercial use would be left to use this provision. 

We also recognize that commercially available testing devices for high powered chargers are slated to 

become more widely available shortly; however, to the best of our knowledge, we understand that at least 

two companies are currently offering this test equipment for sale. The routine availability of validated test 

equipment will promote the ability to type-certify direct current fast charging (DCFC) equipment, which 

is also essential for industry to verify the performance of such equipment prior to use in commercial 

service. Validated equipment prior to commercial operations is vital to ensure the accuracy and 

transparency of measurements on which electric vehicle fueling charges will be based and to ensure 

marketplace equity for competing manufacturers and sellers.

Currently in EVF-24.2 paragraphs S.2.7., N.5.2., and T.2.1. are specified as requirements that become 

enforceable on January 1, 2028 with respect to all DC EVSE systems. Should the submitter further 

modify the proposal as indicated by the WWMA with the intent to make the requirements enforceable to 

equipment only after the effective date, then the text should be changed to italic type. Although this may 

create confusion in the marketplace.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, Perry Lawton (TESCO) spoke in support of the change of the date 

stating that the equipment will be available at the end of this year.

Theo Brillhart (Fluke) supported this modification in anticipating the equipment will be sufficiently 

available to inspectors using this timeline. 

ScheLeese Goudy (Electrify America) is concerned that there is nothing beyond a prototype available at 

this time. Items should not be added to the Handbook in hopes we might be able to have equipment in the 

future because we might be creating a law that cannot be complied with. This item does not address 

legacy equipment. Electrify America recommends making this a developing item so that the submitter can 

address these concerns.

Mike Harrington (Iowa) stated that he can be swayed either way and believes the test equipment will be 

ready. Mike would not mind leaving the 2028 date in place. They recommend developing or 

informational while we await feedback from other regional meetings but does not support voting status. 

The Committee recommends this item as a Voting item.

Western Weights and Measures Association
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At the 2023 WWMA Annual Meeting, due to the S&T Chair Douglas, being a submitter of this item, they 

abstained from the Committee during Open Hearings and Committee Work Group. General comments 

from representatives of California and manufactures of the test equipment were heard on the floor in 

support of this item being moved forward as a Voting item.

ScheLeese Goudy questioned the meaning of the availability and lead time of the test equipment. 

Expressed the concern of how to address legacy devices that are already installed and being used.

Francesca Wahl (Tesla) echoed Electrify America regarding the legacy device issue. Recommend this 

item be Developing status. Perry Lawton clarified the availability of test equipment will be in the first 

quarter of 2024.

Kevin Schnepp (California) stated legacy devices can be addressed with adding the term 

“Nonretroactive”.

Chris King (Siemens) is concerned about the availability of the test equipment and recommends this item 

be Developing status.

The WWMA S&T Committee initially recommended the item be assigned Developing status to allow the 

submitter the opportunity to consider comments heard. After entering into deliberations and hearing from 

Kevin Schnepp that the proposal was fully developed and merited voting status. The Committee agreed 

with a motion to make this a Voting item with specific instructions that industry concerns about legacy 

devices be addressed and to include a nonretroactive date. This Committee notes this makes two items on 

the 2023 WWMA S&T agenda that propose changes to paragraph T.2. Load Test Tolerances (EVF-23.6).

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, Perry Lawton, Tim Chesser (Arkansas), Mauricio Mejia (Florida), 

Gene Robertson (Mississippi), were in support of this item. 

ScheLeese Goudy raised concerns what would happen with legacy equipment. Alex Beaton (EVgo) 

echoed the statements of ScheLeese Goudy. Patrick Bean (Tesla) agreed with Alex and ScheLeese’s 

comments and suggested waiting for test equipment to change the date.

The Committee recommends this item move forward as a Voting item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, a representative from TESCO commented in support of the date 

change to 2025 as equipment is readily available to allow testing. A representative from Electrify 

America expressed concerns on how the date change would affect legacy devices. New Hampshire, 

Vermont, New York, New Jersey, and Massachusetts supports as voting. Upon consensus of the body, 

the Committee recommends this item be Voting.
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EVF-23.4 D S.5. Markings and N.5. Test of an EVSE System

Source: Power Measurements LLC

Submitter’s Purpose and Justification:

Update the details of the recommended tests in HB 44 3.40 to better conform to current practice and 

Publication 14 instructions.

S.5.2

• Change (b) to maximum deliverable amperes because that is the term to be used throughout the 

document. Previously both terms had been used interchangeably.

S.5.3

• Joule is no longer used in the document. Replace with the abbreviation for kilowatt hours.

N.5

• When the HB44 code was originally written there had been no real experience in EVSE testing. 

Additionally, DC EVSE were quite new and power levels were low (typically 50 kW) by today’s 

standards where 350 kW systems are already deployed, and megawatt systems are in discussion. 

The test points chosen at that time have been proven to be less than optimum to verify 

performance of the EVSE. Publication 14, which was developed later than HB 44 adopted a set 

of test points similar to those proposed here. The tests proposed here have been extensively 

discussed in the NIST EVSE Working Group. However, that Work Group ran out of time for a 

formal vote to approve these proposals.

As background, the NIST WG is submitting Form 15s to start the restructuring of the test process. In 

those Form 15s the No Load and Starting load tests are removed from Section 3.40. This proposal 

completes the restructuring of the EVSE testing.

Detailed review of proposed changes:

Logically Section 5.2.1 should follow Section 5.2.2 so both sections have been renumbered.

New 5.2.1

In the new 5.2.1 (formerly 5.2.2) the word Laboratory was added to the title. As the power of both AC 

and DC EVSE has grown rapidly the equipment to test them at full power has become both large and 

expensive. It is perfectly reasonable for NTEP or a manufacturer to have this type of equipment but not 

reasonable for the average Weights and Measures inspector to have it available in the field. For that 

reason, this proposal breaks testing into two types: (1) testing for type verification done in a laboratory or 

at a manufacturer and (2) testing in the field for verification.

For testing AC systems in the laboratory three test points are proposed: 
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i. A point between 10 % and 20 % of the maximum deliverable amperes, but not exceeding 8

A,

ii. A point between 45 % and 55 % of the maximum deliverable amperes,

iii. A point between 70 % and 100 % of the maximum deliverable amperes.

All test points are expressed in terms of a percent of the maximum deliverable amperes of the EVSE. For 

point (i) of the test a restriction has been added to ensure that high current chargers are tested near the 

nominal 6 A load that is the minimum charging current for most vehicles.

Today AC Level 2 chargers typically have maximum currents of 30 A to 80 A. Chargers with currents 

above 32 A were generally unavailable at the time HB 44 3.4 was written. Several vehicles have recently 

been introduced that charge at 48 A. There is only one vehicle currently available that charges at 80 A. 

This test regime can be performed quickly. It can be performed on any AC Level 2 EVSE with test 

equipment commercially available and in the hands of multiple Weights and Measures authorities.

New 5.2.2

Since HB 44 3.40 was initially written a whole new generation of DC chargers have been developed. At 

that time the maximum power delivery was approximately 100 kW at 400 VDC. Today we have 350 kW 

systems operating at both 400 VDC and 800 VDC. The CCS EVSE standards have already been updated 

to allow chargers up to 1000 VDC and 800 A (800 kW). Because there are now two broad classes of DC 

EVSE; 400 VDC and 800 VDC two voltage test points are included. Both voltage classes are capable of 

charging at 400 V so a point between 350 VDC and 400 VDC is required for both. For systems that can 

also operate at 800 VDC a second point between 700 VDC and 800 VDC is required. Current points are 

to be tested at both voltages if they are appropriate for the EVSE.

For DC systems three test points are proposed: 

(i) A point at less than 30 A

(ii) A point between 45 % and 55 % of the maximum deliverable amperes

(iii)A point between 70 % and 100 % of the maximum deliverable amperes

This approach provides a test point at the lower end of the power transfer range where older vehicles may 

charge or where more modern EVs charge when topping off. The other two points are intended to bracket 

the power levels where most EV transfer most of their energy. 

The power levels of DC EVSE are rapidly evolving to ever higher levels. For that reason, this change 

provides for flexibility in field testing of DC EVSE at the high power point. The high current point is 

revised to 20 % to 100 % of the maximum deliverable current with guidance to test at the maximum

power level that is possible using the test equipment available. The new code also provides for using a 

vehicle as the test load providing it meets the 20 % of maximum deliverable current requirement.

One objection might be the creation of a field testing regime for DC EVSE that is less rigorous than that 

applied in the laboratory. For many decades ANSI C12 meter testing has applied testing over the full 

range of voltage and current for meters during type testing but only done validation testing at two current 

values. For example, class 320 meters (320 A maximum current) are tested for accuracy at 11 points 
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between 3 A and 320 A during type evaluation. However, for verification typically only two current 

points are used 5 A and 50 A.

Another objection might be the requirement to test 800 VDC EVSE at both 400 VDC and 800 VDC. 

Only a very few electric vehicles (three at this time) are capable of using 800 VDC charging. Therefore, 

even though an EVSE may be capable of 800 VDC operation because most EV operate at 400 VDC 

testing at 400 VDC on an 800 VDC capable system is appropriate.

The submitter requested that this be a Voting Item in 2023.

NIST OWM Executive Summary for EVF-23.4 – S.5. Markings and N.5. Test of an EVSE System

NIST OWM Recommendation: Developing to resolve the ambiguity of the language that prescribes 

the conditions for performing the test.

• NIST acknowledges that although not reflected in the Item Under Consideration the submitters 

will recommend a return to the pre 2023 requirement for marking of the MCD not the MDA 

(i.e., S.5.2.(b)) to clarify the appropriate terminology to be used for specifying the EVSE 

manufacturer’s highest amperage load rating for operation of the equipment under test and to 

be marked on the device. 

• This proposal removes any reference to the feature used to determine the MDA percentage 

level achieved during accuracy tests and establishes a new MDA range for performing the light 

load test and when a vehicle is the test load for verifying EVFSs.

• The 2023 proposal created a new separate test requirement initially for laboratory evaluations

which are now specified solely for type evaluation; therefore a 2028 exemption would also be 

new text that requires being underscored to clearly designate the 2028 effective date as new 

language. 

• The 2028 effective date is confusing, is the intent that no testing at an approved brick and 

motor facility nor type evaluations can be carried out until January 1, 2028?

• OWM notes that because of the 2028 enforcement date the NIST Handbook 44 General Code 

will continue to apply to existing equipment, including paragraph G-A.3. Special and 

Unclassified Equipment. Jurisdictions wishing to inspect and test existing equipment in order 

to approve it for commercial use would be left to use this provision. 

• A slight change is recommended for the agenda item’s title to include missing paragraphs 

S.5.2.(b) EVSE Identification and Marking Requirements and S.5.3.(d) Abbreviations and 

Symbols; joule and striking S.5. Markings to clarify these units of measurement are a part of 

this proposal. This would also assist the community in distinguishing this item from multiple 

other proposals that address other types of EVFS marking requirements.

• In May 2023 the EVFE Subgroup tasked its Test Procedure Subcommittee (TPS) to undertake 

the project of combining Items EVF-23.4 and EVF-23.7 into a single proposal. After input 

from the submitters of both proposals and other U.S. stakeholders, and multiple meeting 

deliberations (June through December 2023) the TPS arrived at a draft that combines elements 

of both proposals under EVF-23.4 that it will send to the EVFE Subgroup mid-December 2023 

for its consideration. Simultaneously the co-submitters agreed in late August to combine the 
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NIST OWM Executive Summary for EVF-23.4 – S.5. Markings and N.5. Test of an EVSE System

desired elements from both proposals under a single agenda item and to also recommend 

withdrawing of EVF-23.7. 

• Multiple paragraphs appearing under the heading “Item Under Consideration” no longer reflect 

the exact wording or paragraph designations of these requirements as a result of actions which 

occurred during the 31JUL2023-03AUG2023 NCWM Annual Meeting. 

• The NIST Technical Advisor to the TPS has noted there are five places in the submitters’ 

August 2023 alternate test procedures and new definitions needing further refinement to ensure 

uniform interpretation and application of the test procedure requirements (see the NIST OWM 

Detailed Technical Analysis). NIST OWM recommended further edits to clarify test 

procedures where requirements include the terms/phrases: (1) maximum power level; (2) using 

the test equipment available; (3) current levels should be separated to the extent the test 

equipment will allow; (4) installed under optimum conditions (in the definition of MCD); and 

(5) determined by the signal or communication between the EVSE and EV or test equipment

(in the definition of MDA). The 2028 effective date is confusing, is the intent that no testing at 

an approved brick and motor facility nor type evaluations can be carried out until January 1, 

2028?

Table 2. Summary of Recommendations

EVF-23.4 – S.5. Markings and N.5. Test of an EVSE System

Status Recommendation Note* Comments

Submitter Voting Include August 2023 further modifications

OWM Developing 1 Modify August 2023 co-submitter’s draft 

further to clarify terminology 

WWMA Developing Revise per 22AUG2023 submitters’ letter

NEWMA Voting Voting with NEWMA’s fall 2023 changes

SWMA Voting Item needs updates from the submitters

CWMA Voting Voting with its Appendix C changes

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda
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5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Electric Vehicle Fueling Systems as follows:

S.5. Markings. – The following identification and marking requirements are in addition to the

requirements ofSection 1.10. General Code, paragraph G-S.1. Identification.

S.5.1. Location of Marking Information; EVSE. – The marking information required in 

General Code, paragraph G-S.1. Identification shall appear as follows:

(a) within 60 cm (24 in) to 150 cm (60 in) from ground level; and

(b) on a portion of the EVSE that cannot be readily removed or interchanged (e.g., not on a

service accesspanel).

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall 

have the following information conspicuously, legibly, and indelibly marked:

(a) voltage rating;

(b) maximum current deliverable amperes;

(Amended 2023 and 20XX)

(c) type of current (AC or DC or, if capable of both, both shall be listed);

(d) minimum measured quantity (MMQ); and

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C (− 40 °F to + 185 °F).

(Amended 2021)

S.5.3. Abbreviations and Symbols. – The following abbreviations or symbols may appear on 

an EVSE system.

(a) VAC = volts alternating current;

(b) VDC = volts direct current;

(c) MDA = maximum deliverable amperes;

(d) J = joulekWh – kilowatt hours.

(Amended 20XX)

And

N.5. Test of an EVSE System.
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N.5.12. Performance Verification in the Field. – Testing in the field is intended to validate 

the transactional accuracy of the EVSE system. Provided the EVSE under test has a valid type 

approval certificate, then tThe following testing is deemed sufficient for a field validation.

(a) For AC EVSE

(1) A point between 10 % and 20 % of the maximum deliverable amperes, but not 

exceeding 8 A;

(2) A point between 45 % and 55 % of the maximum deliverable amperes; and

(3) A point between 70 % and 100 % of the maximum deliverable amperes.

(b) For DC EVSE

A point at less than 30 A

A point between 20 % and 100 % of the maximum deliverable amperes with guidance to test at the 

maximum power level that is possible using the test equipment available. 

For DC systems it is anticipated that an electric vehicle may be used as the test load. Under 

that circumstance, testing at the load presented by the vehicle shall be sufficient provided that it 

is greater than 20 % of the maximum deliverable amperes.

All DC EVSE are exempt from this requirement until January 1, 2028.

(Amended 2023)

N.5.21. Laboratory Accuracy Testing. – The testing methodology compares the total energy 

delivered in a transaction and the total cost charged as displayed/reported by the EVSE with that 

measured by the measurement standard. Each test shall be performed for at least the minimum 

measured quantity (MMQ).

(a) For AC systems:

(1) Accuracy tests of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a 

total energy delivered of at least twice the minimum measured quantity (MMQ). If 

the MDA would result in maximum deliverable power of greater than 7.2 kW, then 

the test may be performed at 7.2 kW. Shall be performed at the following current 

levels:

(i) A point between 10 % and 20 % of the maximum deliverable amperes, but not 

exceeding 8A;

(ii) A point between 45 % and 55 % of the maximum deliverable amperes; and

(iii) A point between 70 % and 100 % of the maximum deliverable amperes.

(2) Accuracy test of the EVSE system at a load of not greater than 10 % of the 

maximum deliverable amperes (expressed as MDA) as determined from the pilot 
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signal for a total energy delivered of at least the minimum measured quantity 

(MMQ).

(b) For DC systems (see note) tests shall be performed at two voltage points one between 350 

VDC and 400 VDC and if supported by the EVSE a second at between 700 VDC and 

800 VDC:

(1) Accuracy tests of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes current (expressed as MDA) as determined from the digital 

communication message from the DC EVSE to the test standard for a total energy 

delivered of at least twice the minimum measured quantity (MMQ).shall be 

performed at the following current levels:

(i) A point at less than 30A;

(ii) A point between 45 % and 55 % of the maximum deliverable amperes; and

(iii) A point between 70 % and 100 % of the maximum deliverable amperes.

(2) Accuracy test of the EVSE system at a load of not more than 10 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the digital 

communication message from the DC EVSE to the test standard for a total energy 

delivered of at least the minimum measured quantity (MMQ). (2) Accuracy test of 

the EVSE system at a load of not more than 10 % of the maximum deliverable 

amperes (expressed as MDA) as determined from the digital communication 

message from the DC EVSE to the test standard for a total energy delivered of at 

least the minimum measured quantity (MMQ).

All DC EVSE are exempt from this requirement until January 1, 2028.

(Amended 2022 and 2023) 

Note: For DC systems it is anticipated that an electric vehicle may be used as the test load. Under 

that circumstance, testing at the load presented by the vehicle shall be sufficient. Circumstance, 

testing at the load presented by the vehicle shall be sufficient.

NIST OWM Detailed Technical Analysis: 

Most notably, the submitter of this proposal and a corresponding proposal under Item EVF-23.7 

collaborated in August 2023 to combine and further modify portions of both proposals which are not 

reflected in the Item Under Consideration for this item. The co-submitters provided the national and 

regional S&T Committees with these latest alternate modifications to EVF-23.4 in a letter dated August 

28, 2023. Given the effort since May 2023 by the cosubmitters and others within the community to 

combine the two test procedure proposals to address later generations of EVSEs under Item EVF-23.4, 

there appears to be a general consensus to recommend that Item EVF 23.7 be withdrawn from the agenda. 

Additionally, multiple paragraphs appearing under the heading “Item Under Consideration” no longer 

reflect the exact wording or paragraph designations of these requirements as a result of actions which 

occurred during the 31JUL2023-03AUG2023 NCWM Annual Meeting. The EVFS Code modifications 

adopted by the NCWM in early August 2023 for NIST HB 44 Section 3.40 resulted in the: (1) 

renumbering of the test notes (N.), the N.5 test procedure paragraphs were renumbered to become N.3.; 
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(2) requirement for marking of the MDA rather than the MCD (i.e., S.5.2.(b)); and (3) no longer 

recognizing the abbreviation for “joule” while establishing an abbreviation for “kilowatt-hour” (i.e., 

S.5.3.(d)). A slight change is recommended for the agenda item’s title to include missing paragraphs 

S.5.2.(b) EVSE Identification and Marking Requirements and S.5.3.(d) Abbreviations and Symbols

and striking S.5. Markings to clarify the specific code paragraphs under consideration in this proposal. 

This would also assist the community in distinguishing this item from multiple other 2023 proposals that 

address other types of EVFS marking information.

Adoption of EVF-23.1 resulted in the No Load Test and Starting Load Test no longer being part of the 

minimum test procedures for EVSEs (i.e., previously N.1. and N.2. respectively). The unit of 

measurement “joule” was removed from the code because it is not presently in use for expressing 

electrical energy quantity values in commercial EVSE applications. 

Furthermore, the originally suggested modification of paragraph N.5.1. Performance Verification in the 

Field (currently N.3.1.) for testing to be conditional on the EVSE under test having “a valid type approval 

certificate” was removed from the proposal.

Although the community has more knowledge on the operations of EVFSs, test equipment, and 

installation sites there did not seem to be a general consensus on the minimum test criteria to apply to the 

latest AC and DC systems. Variability in test processes and procedures arise from factors that are 

inherent in the device under test, in the test itself, or in test equipment to include the use of an EV as the 

test load. There may be test criteria that cannot be applied in both the laboratory and in the field because 

there are factors the examiner cannot control or adequately correct for. Tests should be conducted over 

the range of operating conditions for which the commercial device is designed. This proposal: (1) 

removes from the test procedures any reference to the feature (i.e., signal or digital communication) used 

to determine the MDA percentage level achieved during accuracy tests; (2) expands the range for 

performing the light load test; (3) sets the minimum current load when a vehicle is the test load for field 

verification of DC EVFSs; (4) establishes a new mid load test; and (5) specifies a new laboratory test 

(which will become the type evaluation test).

The 2028 exemption included in the DC system test procedure amended paragraph N.5.2., a general set of 

test procedures, was adopted as part of the July 2022 priority item that made Section 3.40 a permanent 

code. S&T Agenda Item EVF-23.4, a 2023 carryover proposal, will by May 2023 will be further 

modified by the submitters to adds a separate set of test procedures for type evaluation rather than for 

laboratory conditions which would be a substantive change to the 2024 edition of the handbook. 

Therefore a 2028 exemption, if appropriate, would also be new text that requires being underscored to 

clearly designate the 2028 effective date as part of this newly proposed test procedure. 

The 2028 effective date is confusing, is the intent that no testing at an approved brick and motor facility 

nor type evaluations can be carried out until January 1, 2028? The lack of access until 2028 to 

fundamental requirements, such as these for accuracy tests might possibly lead to nonuniformity in the 

application of DC systems test procedures of the EVSE code. There is a willingness to consider making 

specific portions of the code nonretroactive in order to allow some industry to bring their equipment into 

compliance. As an additional general comment, OWM notes that the NIST Handbook 44 General Code 

will continue to apply to existing equipment, including paragraph G-A.3. Special and Unclassified 

Equipment. Jurisdictions wishing to inspect and test existing equipment in order to approve it for 

commercial use would be left to use this provision. 

In May 2023 the Electric Vehicle Fueling Equipment (EVFE) Subgroup of the U.S. National Work Group 

(USNWG) on Electric Vehicle Fueling & Submetering (EVF&S) tasked its Test Procedure Subcommittee 
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(TPS) with reviewing and providing input on proposed modifications to current NIST Handbook 44 

EVFE accuracy test procedures under Items EVF-23.4 and EVF-23.7. The performance of accuracy tests 

are based in part on the suitability of the test standard and rated operating conditions for the commercial 

device. NIST OWM in the interest of ensuring uniformity and clarity in the interpretation of the cosubmitters’ alternate August 2023 revisions to proposed new paragraph N.3.3. and new definitions (MDA 

and MCD) has made the USNWG’s TPS aware there are several terms and phrases that appear somewhat 

ambiguous and/or out of context with typical handbook language. To provide clarity on the conditions 

that apply in the conduct of an official test NIST OWM has recommended further edits to the cosubmitters’ proposal to clarify test procedure where requirements include the terms/phrases: (1) maximum 

power level; (2) using the test equipment available; (3) current levels should be separated to the extent the 

test equipment will allow; (4) installed under optimum conditions (in the definition of MCD); and (5) 

determined by the signal or communication between the EVSE and EV or test equipment (in the definition 

of MDA). 

NIST OWM suggests further modification for clarifying: 

(1) and (2) The phrase “maximum power level” cited in paragraph N.3.3.(b) applies to the kilowatt rating 

of the EVSE and to assign a value to the power level, either a numerical value or a percentage range in 

relationship to the manufacturer’s power capacity rating for the EVSE with respect to the maximum load 

level acceptable for a valid test rather than basing the test on the capacity of the test standard (note the test 

apparatus should be referred to as a standard not equipment). Suggested modifications would be for 

proposed new paragraph N.3.3.(d) to read: (d) A point between 25 % and 100 % of the maximum 

deliverable amperes with the recommendation to that this test be at the maximum power level within a

that range of ± kW or % kW capacity of the EVSE that is possible using the test equipment 

available.

(3) A proposed new paragraph N.3.3. Note that will apply to test points in subparagraphs N.3.3.(a) and (b) 

so as to not recommend reliance on any available test equipment to achieve a sufficient separation or 

spread between the current levels for the light load test and full load test. The test should be the minimum 

procedures applied to demonstrate compliance of the EVSE to legal metrology requirements across the 

systems entire performance curve. The procedure should specify the spread between the two test points 

that is adequate to be recognized as completing the minimum procedures for a valid test. NIST OWM 

recommends options for the new Note that follows subparagraph N.3.3.(d) to include guidelines that read: 

Note: The test points in (a) and (b) above must not be at the same current level. It is recommended that the current 

levels should be separated to the extent that the test equipment will allowThe range of the difference between the 

maximum deliverable amperes for test points (a) and (b) shall be greater than XX % of the OR at no less than XX.X 

% of the maximum current load capacity of the EVSE. OR XX.% for systems not marked with an accuracy class and 

XX.% for systems marked with an accuracy class. If there are dual accuracy classes of EVSEs in the marketplace.

(4) The proposed new definition of the term “maximum current deliverable” which includes the phrase 

“optimum conditions” include more descriptive text which to be clear to all stakeholders. The definition 

should not provide an exemption for operating conditions where either the site or the system are 

unsuitable since the EVSE should be properly installed, maintained, and used in a manner intended by the 

manufacturer. 

Recommended optional modifications to the proposed new definition for the term “maximum 

current deliverable” for consideration:
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maximum current deliverable. – The maximum current that the EVSE can deliver as specified by the 

EVSE manufacturer when installed under optimum conditions. [3.40]

Note: The installation site shall be adequate for the charging load required by the EVSE and does not

exceed the maximum current specified by the EVSE manufacturer.

OR

maximum current deliverable. – The maximum current that the EVSE can deliver as installed

developed under optimum conditions of installation. [3.40]

Note: The installation site shall be adequate for the charging load required by the EVSE and does not

exceed the maximum current specified by the EVSE manufacturer.

OR 

Either of the above options and a new User Requirement to read:

UR.2.6. Charging Load. - The installation site shall be adequate for the charging load required by the 

EVSE.

(5) Distinguish that the current load delivered from the EVSE during the test is determined by calibrated 

test standard apparatus and not determined by off the shelf equipment. 

Recommended modification to the proposed new definition for the term “maximum deliverable 

amperage” for consideration:

maximum deliverable amperage. – The maximum current available from the EVSE at the time of the test 

as determined by the Control Pilot Pulse Width Modulation signal or via digital communication between 

the EVSE and EV or test equipment standard. [3.40]

(Added 202X)

Additionally, NIST OWM was made aware during September-November 2023 USNWG TPS discussions 

on this proposal that several meeting participants have indicated that some of the recently proposed 

modifications to the test procedures that exist in Handbook 44 may not be suitable for the next generation 

of DC systems that would most likely reach the marketplace. Those comments would need to be 

addressed. It is unknown if the solution would be to add a separate set of requirements for the next 

generation low capacity DC systems, or if there's some other means to remedy that concern and to avoid 

modifications which become barriers to performing accuracy testing.

U.S. National Work Group’s Electric Vehicle Fueling Equipment Subgroup (EVFE SG)

In May 2023 the EVFE Subgroup’s Test Procedures Subcommittee (TPS) was tasked with working 

through a May 2023 version of the test procedures addressed in Item EVF 23.4. This latest modified 

version of the test procedures is the result of the collaborative effort of the submitters of both test 

procedure proposals in Items EVF 23.4 and EVF-23.7. TPS discussions about modifications of the test 

procedures and defining new terms having special and open-ended meaning were focused on input from 

stakeholders (active in type evaluation and routine field testing), the NCWM, regional weights and 

measures associations, and NIST OWM. Based on the TPS's May through December 2023 deliberations 
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the TPS has agreed to forward the combined August 2023 proposal derived from both EVF-23.4 and 

EVF-23.7 for the EVFE Subgroup’s consideration.

Summary of Discussions and Actions: 

At the 2023 NCWM Interim Meeting, Kevin Schnepp (CDFA DMS) recommended a developing status, 

recognizing the item has merit but needs more development. They recommended working with the NIST 

USNWG EVFE Subgroup on item development. Keith Bradley (Electrify America) commented to one of 

the challenges in testing low current with the testing equipment. They expressed concerns with 

N.5.1.(b)(1)(i) and recommends a Developing status to evaluate the Note section. Francesca Wahl (Tesla) 

commented the item needs further development and recommended the submitter work with the NIST 

USNWG EVFE Subgroup on developing the item. Tina Butcher (NIST OWM) commented there was no 

consensus from the NIST USNWG EVFE Subgroup on the item and encouraged the submitter to work 

with the Subgroup to evaluate the merit of the proposed testing criteria.

The Committee considered the comments heard during open hearings and assigned a Developing status to 

the item. The Committee recommends the submitter work with the NIST USNWG EVFE Subgroup for 

item development. The Committee discussed and changed the title to clarify the intent of the proposal.

At the 2023 NCWM Annual Meeting, Bill Hardy indicated the NIST USNWG Subgroup is working on 

updated language.

The submitter of this proposal and a corresponding proposal under Item EVF-23.7 collaborated in August 

2023 to combine and further modify portions of both proposals which are not reflected in the Item Under 

Consideration shown above for this item. The co-submitters provided the national and regional S&T 

Committees with these latest alternate modifications to EVF-23.4 in a letter dated August 28, 2023. The 

August 2023 collaborations modify the 2024 edition of NIST HB 44 Section 3.40 EVFS Code paragraphs 

S.5.2.(b), N.3., N.3.1., and N.3.2., and add new paragraphs N.3.3. and S.5.3.(e) and definitions of the

terms maximum current deliverable” and “maximum deliverable amperage”. The was also a later 

modification* of the combined proposal by the submitters in December 2023 to remove the reference to 

performing tests in new paragraph N.3.3. at “any convenient voltage.” The co-submitters proposal is 

shown below:

August 28, 2023 Alternate EVSE Test Procedure & Related Terminology Proposal 

Developed by the Submitters of EVF-23.4 and EVF-23.7 

(*includes December 2023 modification)

 Modify paragraphs S.5.2.(b), N.3., N.3.1., and N.3.2., and add new paragraphs N.3.3. and S.5.3.(e) 

as follows:

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking requirements of 

Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall have the following information 

conspicuously, legibly, and indelibly marked:

(a) voltage rating;

(b) maximum current deliverable amperes;

(Amended 2023 and 202X)

(c) type of current (AC or DC or, if capable of both, both shall be listed);
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(d) minimum measured quantity (MMQ); and

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C (− 40 °F to + 185 °F).

(Amended 2021)

S.5.3. Abbreviations and Symbols. – The following abbreviations or symbols may appear on an EVSE 

system.

(a) VAC = volts alternating current; 

(b) VDC = volts direct current;

(c) MDA = maximum deliverable amperes;

(d) kWh = kilowatt hour.

(Amended 2023)

(e) MCD = maximum current deliverable

(Added 202X)

N.3. Test of an EVSE System. – The testing methodology compares the total energy delivered in a 

transaction and the total cost charged as displayed/reported by the EVSE with that measured by the 

measurement standard. Each test shall be performed for at least the minimum measured quantity (MMQ). 

N.3.1. Performance Verification in the FieldTesting of an AC EVSE. – Testing in the field is intended 

to validate the transactional accuracy of the EVSE system. The following testing is deemed sufficient 

for a field validation. Accuracy tests shall be performed at the following current levels:

(a) A point between 4 A and 10 A; 

(b) A point between 40 % and 60 % of the maximum deliverable amperes; and

(c) A point between 70 % and 100 % of the maximum deliverable amperes.

N.3.2. AccuracyType Evaluation Testing of a DC EVSE. – The testing methodology compares the total 

energy delivered in a transaction and the total cost charged as displayed/reported by the EVSE with that 

measured by the measurement standard.Tests shall be performed at the following voltage points one 

between 350 VDC and 450 VDC and if supported by the EVSE a second between 700 VDC and 900 

VDC:

Accuracy tests shall be performed at the following current levels:

(a) A point between 10 % and 20 % of the maximum deliverable amperes, but not less than 30 A; 

(b) A point between 40 % and 60 % of the maximum deliverable amperes; and

(c) A point between 70 % and 100 % of the maximum deliverable amperes.

(a) For AC systems:

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a total 

energy delivered of at least twice the minimum measured quantity (MMQ). If the MDA 
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would result in maximum deliverable power of greater than 7.2 kW, then the test may be 

performed at 7.2 kW.

(2) Accuracy test of the EVSE system at a load of not greater than 10 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a total 

energy delivered of at least the minimum measured quantity (MMQ).

(b) For DC systems (see note):

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes current (expressed as MDA) as determined from the digital 

communication message from the DC EVSE to the test standard for a total energy delivered 

of at least twice the minimum measured quantity (MMQ).

(2) Accuracy test of the EVSE system at a load of not more than 10 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the digital communication 

message from the DC EVSE to the test standard for a total energy delivered of at least the 

minimum measured quantity (MMQ).

N.3.3. Performance Verification in the Field of a DC EVSE. – Accuracy test shall be performed at any 

convenient voltage and the following current levels:

(a) A point between 10 % and 20 % of the maximum deliverable amperes, but not less than 30 A;

and

(b) A point between 25 % and 100 % of the maximum deliverable amperes with the 

recommendation to test at the maximum power level within that range that is possible using the 

test equipment available.

Note: The test points (a) and (b) above must not be at the same current level. It is recommended that the 

current levels should be separated to the extent that the test equipment will allow.

For DC systems it is anticipated that an electric vehicle may be used as the test load. Under that 

circumstance, testing at the load presented by the vehicle shall be sufficient for field verification 

provided that it is greater than 40 % of the maximum deliverable amperes and no less than 30 A .

All DC EVSE are exempt from this requirement until January 1, 2028.

(Amended 2022)

Note: For DC systems it is anticipated that an electric vehicle may be used as the test load. Under that 

circumstance, testing at the load presented by the vehicle shall be sufficient. 

(Amended 202X)

Include new definitions in NIST HB 44 Appendix D. Definitions for the terms “maximum current deliverable” 

and “maximum deliverable amperage” as follows:
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maximum current deliverable. – The maximum current that the EVSE can deliver as installed under optimum 

conditions. [3.40]

(Added 202X)

maximum deliverable amperage. – The maximum current available from the EVSE at the time of the test as 

determined by the Control Pilot Pulse Width Modulation signal or via digital communication between the EVSE 

and EV or test equipment. [3.40]

(Added 202X)

Regional Association Reporting:

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, ScheLeese Goudy (Electrify America) stated the NIST USNWG 

discussed this and had consensus of doing the opposite of this proposal. This makes it unnecessarily 

difficult for testing. 

Francesca Wahl opposes due to the high-end testing as written may be challenging for systems with 

higher power levels such as heavy-duty trucks and other high-power systems.

Craig VanBuren (Michigan) requested developing and to send to the NIST USNWG for consideration.

The CWMA S&T Committee has no recommendation for this item.

At the 2023 CWMA Annual Meeting, ScheLeese Goudy noted the Submitter and submitter of EVF-23.7 

are working to submit a single joint proposal. A general consensus on concerns has been reached. SG 

meeting will be convened to discuss technical aspects of joint proposal.

Monica Martinez (Tesla) indicated a draft combination of Items EVF-23.4 and EVF-23.7 is still being 

reviewed for technical accuracy.

The CWMA S&T Committee recommended in May 2023 that this item remain Developing.

At the CWMA 2023 Interim Meeting. the Committee heard comments on this item and Item EVF-23.7 

concurrently. 

Theo Brillhart (Fluke) presented material regarding the merging of Items EVF-23.4 and EVF-23.7 by the 

submitters as well as the passing of item EVF 23.1 at the 2023 NCWM Annual Meeting. The passing of 

Item EVF 23.1 has forced a renumbering of sections within this current proposal. The submitters of Items 

EVF-23.4 and EVF-23.7 have reflected those changes in their proposal. With these changes (letter 

submitted), the submitter recommends this item as voting.

ScheLeese Goudy - agrees with the proposal because it makes testing easier. Language regarding ‘10 

amps or above’ fixes the concerns between Item EVF 23.4 and Item EVF 23.7. Perry Lawton (TESCO)

applauds the work achieved between Items EVF-23.4 and EVF-23.7. Steve Peter (Wisconsin) supported 

this item.

The Committee recommends this item moving forward as a voting item with the proposed changes by the 

submitter which are attached to the bottom of this report in Appendix C.
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Western Weights and Measures Association

During the WWMA 2022 Annual Meeting the following comments were received:

ScheLeese Goudy stated Electrify America opposes this proposal. ScheLeese Goudy suggested the 30 

amps is too small and too low for the 10 % accuracy testing. ScheLeese Goudy recommended a 

Withdrawal status.

Chris King (Siemens) stated Siemens supports and agrees with Electrify America's comments. Chris 

King proposed this item would add significantly to the expense of setting up and running an operation. 

Chris King recommended a Withdrawal status.

Francesca Wahl stated Tesla supports the previous comments by Electrify America and Siemens. 

Francesca Wahl proposed the item can be developed, that there is merit, but is not consistent with the 

working group. Francesca Wahl suggested the item is not fully developed. 

Kevin Schnepp (California Division of Measurement Standards) commented there is some concern about 

the language for specifications and tolerances. Kevin Schnepp recommended this item be assigned to a 

work group. Kevin Schnepp recommended a Developing status.

During open hearings, comments were heard that contents in this item were previously discussed in the 

USNWG, but no official position has been taken by the USNWG. There were also comments during 

open hearing taking the position the item is not fully developed. The WWMA S&T Committee 

recommended the submitters work with USNWG to address the comments heard during open hearings 

and that they work to develop one proposal by combining language from Item EVF-23.7. 

The WWMA S&T Committee recommended that this item be blocked with item EVF-23.7. The WWMA 

S&T Committee recommended the new blocked items be assigned a Developing status.

During the WWMA 2023 Annual Meeting, the Committee heard comments regarding Item EVF-23.7 and 

this item. The WWMA S&T Committee received a letter with updated proposed language for this item 

and Item EVF-23.7. The letter has been posted to the WWMA website [Events – Meeting Documents –

Letter from the Submitters EVF-23.4 and EVF-23.7]. This letter has also been provided to the NCWM 

S&T Committee.

Comments were heard from Theodore Brillhart, ScheLeese Goudy, Perry Lawton (TESCO), Francesca 

Wahl, and Chris King supporting the proposed language in the joint letter dated August 22, 2023.

Kevin Schnepp supported this item with an additional proposed revision of changing the Exemption Date 

from 2028 to 2025.

The WWMA 2023 S&T Committee recommends this item be revised to reflect all proposed language in 

the Joint Letter dated August 22, 2023, and that the item remain Developing to allow all stakeholders the 

ability to review all proposed changes. This Committee recommends the withdrawal of item EVF-23.7 in 

favor of this item with the revisions per the letter. The letter will be posted on the NCWM website.

Southern Weights and Measures Association

The following comments were received during the 2022 SWMA Annual Meeting. ScheLeese Goudy

stated that the test current is too low and recommended withdrawal. Matt Curran (Florida) stated that line 
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17 on page 238 should read N.5.1. The SWMA S&T Committee recommended that this item be 

withdrawn.

At the 2023 SWMA Annual Meeting, ScheLeese Goudy stated this was a joint proposal wand will take 

the place of Item EVF-23.7. Perry Lawton supported this Item. Juana Williams (NIST OWM) stated the 

Test Procedures Subcommittee was asked to provide feedback on an earlier combined proposal as well as 

an earlier proposal. They came back with 10 items they would like addressed and terms like optimal test 

load, convenient voltage, and optimal conditions.

The Committee considered the proposed joint language from a letter dated August 22, 2023 from the 

submitters of both items (EVF-23.4 and EVF-23.7). The item itself still needs to be updated with this 

new language.

Northeastern Weights and Measures Association

At the 2022 NCWM Interim Meeting, Keith Bradley (Electrify America) addressed challenges in testing 

DC meters in that low current is the hardest and perhaps the least important thing to test in the system. 

After hearing comments from the floor, the Committee believed this item had merit and requested that the 

EVSE Subgroup continue work on this item. The Committee recommended this item be given a 

Developing status.

At the 2023 NEWMA Annual Meeting, William Hardy (Power Measurements, LLC) gave a short 

presentation. When this proposal was submitted, there were not many DC chargers around and 50 kW

was considered high power. Currently, 3 megawatt chargers are available and soon 10 megawatt will be 

available. International standards are catching up with rapid progress of the industry. The USNWG has 

been working extremely hard to keep HB 44 up to date. The submitters of this proposal and Item 

EVF-23.7 wish to get the items in the handbook prior to 2025. Bill Hardy was looking for support from 

NEWMA to find a path to address this sooner than 2025. ScheLeese Goudy stated that the submitters 

have been working to find a solution between Items EVF-23.4 and EVF-23.7 and will have an update 

soon. Alicia Artessa (Tesla) stated that Tesla supports development with the USNWG and working with 

submitters of Item EVF-23.7. James Cassidy (Massachusetts) asked if there is a consensus to ask for an 

emergency item from NCWM BOD and that we need to figure out how to test the devices and with what 

parameters. Devices are being installed but how are we supposed to test them. James Cassidy asked if 

there is any type of documentation that when installed, shows what specifications the installers are using 

and if the device passes. Loren Minnich (NIST OWM) stated that OWM agrees that the USNWG should 

be consulted on Items EVF-23.4 and EVF-23.7. NIST is currently developing testing guidance 

documents and trying to address minimum test procedures. NCWM Chair Albuquerque stated that the 

two items are still in developing status and if the submitter is trying to elevate to voting before the Annual 

meeting, at minimum there should be a consensus between the submitters of both items prior to 

requesting an emergency item. Cheryl Ayer (New Hampshire) concurs with moving this item forward. 

Perry Lawton is in agreement with moving forward to at least get a definition of what a field test is so 

they can develop test equipment. Jim Willis (New York) sees an uphill battle to change this to voting 

status for the July 2023 NCWM Annual Meeting. 

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

a developing status and not request that the NCWM S&T Chair consider this a priority item, and the body 

concurred.
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At the 2023 NEWMA Interim Meeting, a representative from Electrify America provided a presentation 

on updates with this proposal. Comments were heard that the submitters of Items EVF-23.4 and EVF--

23.7 worked together on a joint proposal to come to a consensus on low end testing and specify minimum 

loads on DC meters. A representative from TESCO commented that the new proposal provides realistic 

testing constraints that will last and establishes minimums and parameters for “man in the middle” 

testing. Upon consensus of the body, the Committee recommends this item be Voting with the following 

changes:

Strike the entirety of paragraph N.3 and replace with:

N.3. Test of an EVSE System. 

The testing methodology compares the total energy delivered in a transaction and the total cost charged 

as displayed/reported by the EVSE with that measured by the measurement standard. Each test shall be 

performed for at least the minimum measured quantity (MMQ).

N.3.1. Testing of an AC EVSE

Accuracy tests shall be performed at the following current levels:

(i) A point between 4 A and 10 A; and 

(ii) A point between 40 % and 60 % of the MDA; and

(iii) A point between 70 % and 100 % of the MDA.

N.3.2. Type Evaluation Testing of a DC EVSE

Tests shall be performed at the following voltage points one between 350 VDC and 450 VDC and 

if supported by the EVSE a second at between 700 VDC and 900 VDC:

Accuracy tests shall be performed at the following current levels:

(i) A point between 10% and 20% of the MDA, but not less than 30 A;

(ii) A point between 40 % and 60% of the MDA; and

(iii) A point between 70 % and 100 % of the MDA.

N.3.3. Performance Verification in the Field of a DC EVSE

Accuracy tests shall be performed at any convenient voltage and the following current levels:

(i) A point between 10% and 20% of the MDA, but not less than 30 A; and

(ii) A point between 25 % and 100 % of the MDA, with the recommendation to test at 

the maximum power level within that range that is possible using the test equipment 

available. 
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Note: The test points (i) and (ii) above must not be at the same current level. It is 

recommended that the current levels should be separated to the extent that the test 

equipment will allow. 

For DC systems it is anticipated that an electric vehicle may be used as the test load. Under 

that circumstance, testing at the load presented by the vehicle shall be sufficient for field 

verification provided that it is greater than 40 % of the MDA and no less than 30 A.

All DC EVSE are exempt from this requirement until January 1, 2028.

Change S.3.2 (b) to read:

(b) Maximum current deliverable

Add S.3.3 (e) to read.

(e) MCD = Maximum current deliverable

Add the following definitions to Appendix D:

Maximum current deliverable: The maximum current that the EVSE can deliver as installed under 

optimum conditions. 

Maximum deliverable amperage: The maximum current available from the EVSE at the time of the 

test as determined by the Control Pilot Pulse Width Modulation signal or via digital communication 

between the EVSE and EV or test equipment.

EVF-23.6 S.5.2. EVSE Identification and Marking Requirements and T.2. Tolerances

Source: Florida Department of Agriculture and ConsumerServices; Electrify America; 

Tesla; EVgo, Siemens

Submitter’s Purpose and Justification:

The revised proposal would amend Handbook 44, Section 3.40. Tentative Code in the following ways:

1. Paragraph T.2.1. would be revised for DC chargers. The 1 % (acceptance) / 2 % (maintenance)

tolerances would apply to devices installed after January 1, 2024. For devicesinstalled before

that date, the tolerances would be 5 % (acceptance and maintenance).

2. For the sake of clarity and transparency for customers and inspectors, a device subjectto the 5 %

tolerance would have to be marked as such. The proposal would require specific language for

the marking.

3. If a manufacturer has achieved 1 % capable chargers earlier than the January 2024 timeframe,

users of those chargers might prefer not to mark the chargers as 5% chargers; and thenthose

chargers would be subject to the 1 %/2 % tolerance. The proposal includes language to establish

this treatment.
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The 5 % tolerance for pre-2024 chargers would end on January 1, 2034. After that date, all DC chargers 

would be subject to the 1 % (acceptance) / 2 % (maintenance) tolerance. 

A. The effect of the proposed revisions

The changes we propose would work as follows: all DC chargers would remain exempt from the

accuracy tolerances until January 1, 2028, as NCWM adopted at the 2022 Annual Meeting. When

accuracy tolerances come into force, a DC charger installed after January 1, 2024, would have to satisfy

the 1 % (acceptance) / 2 % (maintenance) tolerance, the same levels as for AC chargers. But a DC

charger installed before January 1, 2024, would have to meet only a 5 % accuracy tolerance. That 5 %

accuracy tolerance would expire on January 1, 2034, at which point all the legacy chargers will have to

have been retrofitted or replaced.

The proposal would require a charger that is subject to the 5 % tolerance to display a marking, with

specified language, informing customers and inspectors of that fact. But the proposal leaves open the

possibility that a given manufacturer might achieve the 1 % / 2 % tolerance earlier, and then would

specify that capability for a given model. Devices in that model would not have to bemarked as 5 %

devices; but if they are not marked that way, they would of course be subject to the 1 % / 2 % level as

for new chargers.

B. The basic justification

DC and AC chargers are fundamentally different—in technology, in customer use, and in metering 

capabilities. AC charging technology, the older form, delivers energy in the same form—voltages and 

currents oscillating at 60 Hertz (in the United States) as utilities have provided it for a century. 

Because a vehicle has to convert AC energy to DC for charging the battery, AC charging stations operate 

at no more than 19.7 kW, and most no more than 6-7 kW. These charging rates will add 24-80 miles of 

range in an hour of charging a typical car, and consequently AC charging involves extended sessions—

the median time that a customer uses an AC station is 22 hours. 1

 The voltages delivered are no more than 

480 volts AC, and the current is no more than 50 amps AC (and more typically 30 amps AC). By 

contrast, DC chargers deliver energy in the same form that a battery ultimate needs it. Using voltages of 

400 to 950 volts DC and currents up to 500 amps DC (higher levels are coming in the future for 

applications like charging heavy trucks), they are able to deliver 50kW, 150 kW, 350 kW, or higher 

charging rates. These stations will add 200-1400 miles of range in an hour of charging, or, more 

meaningfully, 400 miles of range in as little as 20 minutes. A customer at a DC station will arrive, charge 

briefly, and then depart. Customers incorporate AC chargers into their regular routines, such as by 

driving to work and charging there. DC chargers are more commonly used to support long-distance 

trips.2

For AC charging, manufacturers have been able to utilize metering technology that has been developed 

over a century for electric utilities. When Handbook 44, Section 3.40 was developed in 2015, that AC 

metering technology was well understood. There have been long-established standards for AC revenue 

meters—though those standards, in the utility sector, are not necessarily the same in every respect as how 

1 Idaho National Laboratory, “Plugged In: How Americans Charge Their Electric Vehicles,” p.14, 

https://avt.inl.gov/sites/default/files/pdf/arra/PluggedInSummaryReport.pdf.

2 As the California Energy Commission has explained, “it is therefore useful to treat infrastructure for interregional 

travel (predominantly DCFCs) differently from infrastructure for intraregional travel (predominantly Level 1 and 

Level 2 chargers).” https://efiling.energy.ca.gov/GetDocument.aspx?tn=233986&DocumentContentId=66805 at 

page 14.
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a weights and measures standard would work. One indication of the relatively mature state of AC 

metering is that NIST has long provided ordinary-course calibration services for AC watt-hour meters that 

operate at 60 Hertz, within ranges of 69 to 480 volts and 0.5 to 30 amps (sufficient to cover typical AC 

chargers).3

 DC metering technology, by contrast, has been “in research and development.”4 When 

section 3.40 was adopted, the accuracy tolerances of 1.0 % (acceptance) and 2.0 % (maintenance) were 

predictive and aspirational for DC chargers. As of November 2019, when California adopted its own 

regulation based on section 3.40, meters and chargers meeting that standard were not yet generally 

commercially available.5

 Meanwhile, NIST calibration services for DC watt-hour meters are nonstandard, and are available only up to 240 volts and 5 amps6

—far below the levels needed for testing DC 

chargers.

Argonne National Lab has studied the availability of DC metering technology. Our understanding is that 

its draft report (not yet finalized, so far as we are aware) concludes that there are now on the market (at 

least in principle) meters for use in DC chargers that can meet a 1 % acceptance / 2 % maintenance 

tolerance. It is reasonable to conclude that the 1 % / 2% tolerance will be achievable in general. The 

current proposal is focused on how to handle the chargers that are installed before that point. Previously 

installed chargers will not in general be able to satisfy a 1 % / 2 % accuracy tolerance. To be clear, we do 

not suggest that every existing charger would be more than 2 % inaccurate. Indeed, it would not 

genuinely be possible to make that assessment, given the lack of NIST-traceable measurement apparatus 

to test fast DC chargers in the field.

There is presumably a distribution of potential deviations among devices in the field. Given what

metering technology has been commercially available, a 2 % maintenance accuracy would lead to

inspection problems for a high proportion of devices.

The proposal would establish a tolerance of 5 % for devices installed before January 1, 2024. The 

justification for this particular choice of tolerance and timeline is as follows:

1. In 2019, California adopted a regulation that put a modified version of Section 3.40. into force

for new devices. DC chargers installed before January 2023 are subject to no weights and

measuresstandards at all until 2033. DC chargers installed after January 2023 (and before

January 2033) are subject to a maintenance tolerance of 5.0 % (and acceptance tolerance of

2.5 %). Consequently, in California, which represents roughly 30 % of the currently-existing

base of DC chargers, the maintenance tolerance will be 5.0 % for the coming decade. A

maintenance tolerance of 5.0 % for legacy chargers in section 3.40 will be stricter overall than

the California regulation (because it will apply to all legacy chargers, whereas the California

standard applies only to post-2023 chargers) but will align with the numerical tolerance used in

California. Although a 5.0 % tolerance is among the larger tolerances used in Handbook 44, it

is not unprecedented. And the fact that newchargers in California will be subject to that

standard will mean EV charging customers have substantial experience with that chargers at that

tolerance, and the 5.0 % tolerance we propose would be the same transactional experience as

customers in California (the largest EV charging market in the country) receive. It bears

mention, too, that as Measurement Canada prepares to implement standards for AC chargers, the

3 https://shop.nist.gov/ccrz__ProductDetails?sku=56110S&cclcl=en_US.

4 Cal. Dept of Food & Agriculture, Final Statement of Reasons on Electric Vehicle Fueling Systems, p.23 (Nov. 1, 

2019).

5 Id.

6 https://shop.nist.gov/ccrz__ProductDetails?sku=56110S&cclcl=en_US
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tolerance (acceptance and maintenance) will be 3.0%, not the 1 % acceptance in Handbook 44. 

The cost of a typical charging session is $15 to $20. A 5.0% maintenance standard would mean

a variation, beyond that, of an additional plus or minus 40 cents. As with any tolerance, that

variation could at any given charger be for or against either side to the transaction.

2. The industry submitters have studied carefully their existing chargers, measurement devices and

existing models now available. They believe the 5 % maintenance tolerance is achievable at 

a manageable cost in the future, because it will generally not require extensive reconfiguring 

of cabinets and the installation of four-wire cables.

3. The cost of bringing legacy chargers into line with the 1 % / 2 % standard would be extreme. 

Although equipment is not available to test DC fast chargers in the field, some operators have 

found in tests of existing devices that they can be brought to a 5 % tolerance but cannot meet the 

1 % / 2 % standard without replacing the meters or implementing an entirely new measurement 

system, which means a physical reconfiguration at each station and/or replacing the cables for 

delivering the energy to vehicles. Section 3.40. standards are based on the energy delivered at the 

connector to the car; in other words, a charger must account for losses in the cables. The most 

straightforward way to account for losses is to measure the voltage at the vehicle connector; that 

means the cable must have two additional high-voltage leads, to carry that voltage back to the 

meter 7

. In California’s Initial Statement of Reasons (ISOR) for adopting specifications and 

tolerances requirement for commercial EVSE, California estimated that it costs approximately 

$20,000 to retrofit an existing DC charger.8

 We understand that cost to represent the cost (parts 

and labor) to replace the charging cable, and possibly to replace the meter if that task is simple. 

This cost may be a significant underestimate for some models of charger, because replacing the 

meter may not always be possible without physical reconfiguration of the space within the 

charger. Which charger models would require that sort of reconfiguration, and what proportion 

of the installed base they represent, is impossible to know without a detailed model-by-model 

study and detailed model-by-model installation data across manufacturers. The upper end of cost 

would be simply the cost of replacing a charger, which many operators would find preferable to 

physical reconfiguration of charger internals anyway. The International Council on Clean 

Transportation (“ICCT”) reported in 2019 that fast DC chargers cost between $75,000 and 

$140,000 per charger, for the charger itself. 9

 Installation costs range from $18,000 per charger 

(for six 150 kW chargers at a site) to $65,000 per charger (for one 350 kW charger at a site).10 

The total cost (installation and equipment) for a 4-charger site would be roughly $720,000. That 

said, some amount of the installation cost represents upgrades to electrical supply lines and basic 

site construction, costs that would not be incurred anew to replace equipment. So, for a rough 

estimate, it is appropriate to use the lowest cost estimate from the ICCT, which is $17,692 (the 

cost per charger for a large site of 50 kW chargers). With that figure, replacing a 4-charger site of 

350 kW chargers would cost roughly $630,000, or $157,000 per charger.

7 Charging cables are themselves complex objects, with liquid coolant and high-voltage insulation. Cables for fast 

DC chargers that include additional high-voltage sensing leads were not available in 2015.

8 https://www.cdfa.ca.gov/dms/pdfs/regulations/EVSE_ISOR.pdf.

9 Michael Nicholas, “Estimating electric vehicle charging infrastructure costs across major U.S. metropolitan areas,” 

ICCT Working Paper 2019-14, p.2 tab. 2 (Aug. 2019), 

https://theicct.org/sites/default/files/publications/ICCT_EV_Charging_Cost_20190813.pdf.

10 Id. at 4 tab. 4.
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4. Based on data on the existing charge base from the National Renewable Energy Laboratory’s

Alternative Fuels Data Center (“AFDC”), we can assume there will be about 36,000 “pre-2024” 

DCchargers.11 These are only a fraction of the overall chargers that will be installed nationwide

over the coming decade but bringing them into compliance with a 1 % / 2% tolerance will be

highly costly. Taking out the 30 % that are in California (which already has regulations with a

5.0 % maintenance tolerance, for all post-2023 DC chargers), retrofitting all of those at the

$20,000 cost would total $720 million. If meter replacement is not possible and those chargers

must all be replaced, the total would be $5.6 billion. The actual cost of bringing the pre-2024

chargers to compliance with a 2.0 % maintenance tolerance would be somewhere between these

numbers. 12The January 2024 date moves faster than the California regulation. Under the

California regulation, the 1 % / 2 % tolerance would not come into force until 2033. It appears

that meters capable of that tolerance are now available on the market. The submitters propose

January 2024 as the date for distinguishing “legacy” from “new” chargers, because the existence

of these meters on the market is not all that is needed. Manufacturers have to access the meters,

design products incorporating them; revise production lines; test the new products to ensure they

are safe and reliable; and obtain third-party certifications (such as from Underwriters

Laboratory) of the revisedproducts. After those steps, a manufacturer can begin delivering a

revised product to operators. Installation of a charger is not simply a matter of placing it on a

counter; charging sites involve construction work, leading to the secure attachment of a charger

to a specially built concrete pad. In other words, from the first delivery of a new model of

charger to the first installations of thosechargers also takes time. The January 2024 date is

appropriate for expecting new chargers to incorporate meters that were available a few years

before that date.

5. The proposal focuses on installation before January 2024, rather than using the concept of 

retroactive/non-retroactive that is more common in Handbook 44, because non-retroactive is 

ordinarily based on when a device is placed in service. Many states do not yet regulate EV 

chargers and consequently have no placed-in-service process. In these states, “placed in service” 

would not be a well-defined concept, and regulators might not have good ways to determine when 

a device was placed in service. Installation is a reasonably well-defined process, and it should be 

possible to identify when a given charger was installed. California’s regulation has differing 

status for pre-2023 and post-2023 chargers, and it bases that line on installation.

6. The proposal also specifies 5.0 % as the acceptance tolerance, not just the maintenance tolerance. 

As a practical matter in field inspections, the acceptance tolerance for pre-2024 chargers will not 

be important. Section 3.40 (as amended at the 2022 NCWM meeting) exempts DC chargers from 

the accuracy tolerance until 2028. When they become subject to accuracy tolerances, no pre2024 charger will be at the point of acceptance. The proposal specifies an acceptance tolerance 

11 According to the AFDC’s station locator database, there are 6,580 DC stations with 22,767 chargers. The AFDC 

also reports that the number of DC ports grew 29% year-on-year to the second quarter of 2021. 

https://afdc.energy.gov/files/u/publication/electric_vehicle_charging_infrastructure_trends_second_quarter_2

021.pdf. With growth at this rate, about 6,600 additional DCFC stations will be installed in 2022 and 2023, leading 

to a total of about 36,000 DC chargers that would be “pre-2024” chargers under the proposal.

12 A charger that is not qualified for a given tolerance level may well be within the bounds of the tolerance, because 

there is some distribution in metering performance. Even if devices are replaced only after inspection, a significant 

fraction would need replacement, thus incurring this scale cost. Moreover, it might be most sensible for an operator 

to ensure all its devices are qualified, rather than waiting to see what the results of inspection might be for a given 

charger.
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for clarity in type evaluations, which ordinarily evaluate device models against the applicable 

acceptance tolerance.

7. The exemption until 2028 adopted at the 2022 meeting does not eliminate the need for this 

proposal. When DC chargers are subject to accuracy tolerance requirements, pre-2024 chargers 

will still need to meet the applicable tolerance or be retrofitted or replaced. The 2028 timeframe 

is unreasonably soon to do that, given the cost estimates above. California estimated that 

chargers have an effective 10-year lifespan.13 This estimate is highly uncertain, in part because it 

was based in part on older AC chargers. Newer DC chargers, using more advanced technology 

for significantly more expensive equipment, are likely to have usable lifetimes greater than 10 

years. The proposal recognizes that, nonetheless, there is a tradeoff between the cost of 

retrofitting or replacing devices, and the value of tighter tolerances. Some number of chargers 

will fail and need replacement earlier than 10 years, thus reducing the number that eventually 

need to be retrofitted or replaced to comply with tighter accuracy tolerances. Overall, the 

proposal uses the same 10-year period that several states have already adopted. 14 Notably, the 

effect is significantly more stringent than in the California regulation. Under California’s rule, a 

charger installed before 2023 is subject to no standards for 10 years, and then becomes subject to 

standards in 2033; a replacement of the charger in 2032 would be subject to the 5.0 % 

maintenance tolerance. A charger installed in 2023 (and that hypothetical 2032 installation) 

would be subject to the 5.0 % tolerance indefinitely, with no end point. Our proposal, by 

contrast, would make a pre-2024 charger subject to the 5.0% tolerance once the 2028 compliance 

dates kicks in but only until 2034, at which point the charger would have to be retrofitted, 

replaced, or otherwise brought to the 1 % / 2% tolerance.

C. Potential objections

In response to the industry’s original proposal, some people commented that AC and DC chargers should 

be treated the same. As explained above, they are not the same, not only because of technology 

differences but also because customers use them and view them differently. California and NTEP have 

distinguished AC and DC chargers since at least 2021, and NCWM has already recognized important 

differences between them, in NIST Handbook 44.

Some have also commented that there should not be parallel accuracy classes for a given application. 

But this approach is not unprecedented. In 1986, NCWM required new scales to be marked with an

accuracy class. Pre-1986 scales could remain unmarked, and those unmarked scales were subject to

various accuracy tolerances (depending on application) that ranged up to 5.0 %, compared to the largest

tolerance for any marked scale at 2.0 %. For grain moisture meters, Handbook 44 has completely

separate sections for pre-1998 and post-1998 devices, with some different tolerance specifications for

older and newer devices. For both scales and grain moisture meters, there was no sunset date; the older

devices have been allowed to continue in use for as long as they operated. We do not suggest that the

circumstances with EV chargers are the same. Each of those past examples was based on justifications

particular to that situation. Nonetheless, these examples show that it has been done to maintain parallel

tolerances for a given application. In addition, there are already parallel, differing tolerances for EV

chargers. If the proposal is not adopted, pre-2023 chargers in California will have no tolerance at all

until 2033; post-2023 chargers will have a 5.0 % maintenance tolerance for the indefinite future; and

chargers elsewhere in the country, including in states neighboring California, will have the existing

13 Cal. Department of Food & Agriculture, Final Statement of Reasons, p.6.

14 California. Code of Regulations § 4002.11; Rev. Code Wash. § 19.94.190(6).
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Handbook 44 tolerances. The proposal shifts the line between differing tolerances, but the situation of

differing tolerances for the same application is already in place without the proposal.

There have been claims that some manufacturers may be able to achieve 1 % devices (DC chargers)

before January 2024, and one or more may already have done so. Even so, the proposal is still

warranted. Operators of EV chargers should not be forced to replace their existing chargers simply

because they could not get access to chargers made by a given manufacturer. It is generally agreed that

when section 3.40 was adopted, the equipment to satisfy it did not exist for DC chargers. Reaching that

point has required research and development by meter manufacturers andcharger manufacturers. The

goal of regulation should be to handle the technology transition in a reasonable, fair manner, without

prejudice to operators that have made diligent efforts in procurement and operation of their chargers.

This proposal arrives without the formal approval of the USNWG subgroup on EV charging. But a

similar proposal did have general consensus at the Work Group. NIST personnel solicited views on the

proposal through an email ballot at the end of June 2022. The resulting votes were 11 in favor, and 1

opposed. As of this filing, NIST has not provided information on whether this vote was sufficient for

the subgroup to formally endorse the proposal. The one-person voting “no” said that the person would

have voted yes if the proposal included a 10-year end date for the 5 % tolerance. The current proposal 

has that feature and thus addresses the only concern expressed by the sole “no” vote. The current

proposal has that feature and thus addresses the only concern expressed by the sole “no” vote.

NIST OWM Executive Summary for EVF-23.6 – S.5.2. EVSE Identification and Marking 

Requirements and T.2. Tolerances

NIST OWM Recommendation: Developing to allow for deliberations on the enforcement dates and 

establishing parameters for use of an electronic display.

• Initially NIST OWM suggested a review of Items EVF-23.5 and EVF-23.6 where both items 

propose changes to marking and accuracy requirements in NIST Handbook 44.

• OWM has given thought to how we might assist the Committee and the Community in 

addressing these items in arriving at a single proposal that would meet the needs of the 

submitters of both items and other stakeholders.

• OWM believes this proposal (Item EVF-23.6) and the alternative recommended in Item 

EVF- 23.5 both required more work and vetting as suggested by two of the four regional 

associations. Voting Item EVF-23.6 needs further refinement.

• OWM believes this preliminary work would have been done in the USNWG SG as 

recommended during the WWMA meeting and recommended the Committee designate these 

items as Developing in 2023 and asked the SG for assistance in vetting the proposals. 

Adoption should occur only after fully vetting proposals by the entire community as the 

submitter(s) may be too close to the subject or take too wide a berth in the development of new 

or modification of existing requirements resulting in either overlooking or oversimplifying the 

lessons learned in the marketplace which can lead to misreading the complexities of 

commercial applications which have necessitated legal metrology controls. It has been 

reported that when addressing the level of confidence that buyers and sellers have, and the 

accuracy with which these transactions are performed that: The consumer has no way to verify 

the accuracy of the transaction and must rely on the accuracy of the fuel dispenser.
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NIST OWM Executive Summary for EVF-23.6 – S.5.2. EVSE Identification and Marking 

Requirements and T.2. Tolerances

• In anticipation that the Committee believed there was an urgent need to move one of these 

proposals forward, OWM encouraged the Committee to use the proposed language in Item 

EVF-23.5 as a starting point to ensure clarity and understanding of the final language.

o Having well-defined tolerances with clear and understandable effective dates is essential.

o Defining tolerances that are enforceable in the specific device codes is also preferable to 

the alternative of having jurisdictions use the provisions of the General Code to implement 

tolerances suitable for the application since this has the potential for non-uniform 

application across the country.

• As shared in its comments in Item EVF-23.5, OWM believes the proposed changes in Item 

EVF-23.5 was much clearer in language, format, and application and are closer to language 

agreed to by the USNWG SG for ballot in June 2022 than are the proposed changes in Item 

EVF-23.6. OWM is aware of the Committee’s decision to withdraw Item EVF-23.5.

o The USNWG EVFE Subgroup gained momentum as the result of a June 2022 ballot in 

which the group agreed to move forward to recommend a wider tolerance of 5 percent 

only for DC systems installed before 2024 that must bear accuracy markings while 

maintaining for AC systems a 1 percent Acceptance Tolerance/2 percent Maintenance 

Tolerance and the tighter tolerance would also apply to post 2024 DC systems.

o The language from the June 2022 ballot is included in OWM’s detailed analysis below 

and in the history on Item EVF-23.5.

• There were differences between the language recommended in that June 2022 SG ballot and 

that proposed in Item EVF-23.6. The language recommended in the June 2022 ballot:

o Permitted DC devices installed before 2024 to have a wider tolerance if they were clearly 

marked to designate their accuracy.

o Included a wider tolerance of 5 % for DC systems installed before 2024 when accuracy is 

marked, which several OEMs identified as achievable. Note: The June 2022 SG’s 

language did not include an exemption for DC systems from accuracy tolerances up 

through 2028 to sunset in 2034 and was a more suitable option.

o Recognized the EVFE Subgroup would further refine the requirement’s text. 

• OWM acknowledged a Florida, Electrify America, Tesla, EVgo, and Siemens’ October 15, 

2022, letter sent to the S&T Committee regarding EVF-23.6 and a June balloted proposal of 

the USNWG EVFE Subgroup (SG). OWM submitted the following clarifications regarding 

this letter to the S&T Committee.

o NIST OWM, as convenors of the EVFE SG, sent a response to the Committee indicating 

that although the results of the Subgroup’s June 2022 ballot indicate the group’s support 
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NIST OWM Executive Summary for EVF-23.6 – S.5.2. EVSE Identification and Marking 

Requirements and T.2. Tolerances

for modifications to tolerances and marking requirements this should not be construed as 

supporting the specific changes proposed in EVF-23.6.

o There are some key differences between the Subgroup’s June balloted proposal and EVF23.6. Specifically, the Subgroup’s proposal does not include two different retroactive 

dates and differs in the magnitude of the tolerances and specific conditions under which 

they would apply, the permissible format required for markings (which are not indelible, 

do the submitters have a label or electronic only in mind?) and reference to certification. 

The convenors of the Subgroup will continue to provide written and verbal input as 

explicitly directed by the group. 

• It also is written that the components of the weights and measures infrastructure help to ensure 

the accuracy and validity of commercial transactions based upon weight, measure, or count and 

to ensure that the quality of products meets required quality standards. Another purpose of 

these components is to ensure consumers are informed so that they can make value 

comparisons. A robust infrastructure ensures equity in the marketplace, meaning that 

consumers receive the correct quantity and quality of products and services for which they pay, 

and businesses receive fair payment for the products and services that they deliver. By 

ensuring that they operate according to a consistent set of weights and measures standards and 

practices, businesses are also protected from unfair competition.

• Below are some additional comments for the Committee and other stakeholders to have 

considered in their review of Item EVF-23.6:

o Use of the terms “load” and “accuracy” should be reviewed for consistency in their use in 

the titles of the two T.2. subparagraphs.

o The community should revisit past national discussions on the electronic formatting of 

required marking information and also consider April 2023 comments raised in the EVFE 

Subgroup ballot for specifying a minimum time for the duration of the displayed accuracy 

statement and the statement be capable of being viewed in entirety prior to use of the 

EVSE. 

• Adoption should occur only after fully vetting proposals to modify fundamental requirements 

such as those that impact accuracy, transparency, or that ensure fair competition to:

o avoid unforeseen consequences;

o ensure stakeholders have the appropriate tools needed for this new device application;

o discourage nonuniformity which can have a disruptive influence on the marketplace; and

o take corrective action on discovering any gaps/oversight in modifications to the sevenyear-old legal metrology requirements.

• Where commercial equipment is known to operate at dual tolerances the proposed marking and 

performance requirements should be retroactive. Although there is likely to be some 
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NIST OWM Executive Summary for EVF-23.6 – S.5.2. EVSE Identification and Marking 

Requirements and T.2. Tolerances

discussion as to what nonweights and measures agencies designate as a “public” station; the 

DOE EERE Alternative Fuels Data Center provides the number and location 

(stations/ports/charging levels) of alternative fueling installations in each state on the EERE 

website available at: https://afdc.energy.gov/stations/states.

• NIST OWM acknowledges that the EVFE Subgroup met on December 8, 2022 and March 2 

and 6, 2023 to address proposals under consideration for the 2023 standards development cycle 

and the SG provided a July 12, 2023 memorandum on its position in support of the Item Under 

Consideration for Item EVF-23.6 as it appears in the Committee’s Interim Meeting Report 

(PUB 16).

• NIST OWM encourages the community's participation in the USNWG EVFE Subgroup which 

began its work in 2012 and whose work resulted in NIST HB 44 3.40 EVFS Code's adoption in 

2015. The Subgroup has reviewed the four paragraphs that appear in multiple 2023 proposals 

that address: (1) dual EVSE tolerances (2.0 percent or 5.0 percent [DC EVSEs]); (2) new 

EVSE markings required for the wider tolerance in the marketplace; and (3) corresponding 

accuracy test procedures.

• There are several dates referenced in proposed EVF-23.6 paragraph T.2.2. Tolerances that 

conflict and OWM believes will create confusion for those implementing the proposed 

requirements.

o The statement adopted by the NCWM in July 2022 exempting DC devices from any 

tolerance requirements until 2028 remains in the proposal, yet there is a date of 2024 in 

both the proposed paragraph T.2.2.(a) and paragraph T.2.2.(b) which specifies 

requirements for DC devices installed prior to 2024. This is confusing and widens the 

gap: (1) in time delays in the application of tolerances in what will be a dual tolerance 

marketplace for DC systems (2) that encourages nonuniformity in equipment 

performance and (3) in the timely marking of information for consumer awareness.

o Proposed paragraph T.2.2.(a) references a sunset date of 2034, yet there is still a statement 

referring to a 2028 date, creating a conflict. Additionally, the 2034 date is 6 years after 

the 2028 date that was adopted by the NCWM in July 2022. The rationale for establishing 

a sunset date of 2034 for the entire country, given the pace at which technology has 

already advanced, is nineteen years after the tentative code was first adopted by the 

NCWM.

• There were differences between the language recommended in that June 2022 SG ballot and 

that proposed in Item EVF-23.6. The language recommended in the June 2022 ballot:

o Permitted DC devices installed before 2024 to have a wider tolerance if they were clearly 

marked to designate their accuracy.

o Included a wider tolerance of 5 % for DC systems installed before 2024 when accuracy is 

marked, which several OEMs identified as achievable. Note: The June 2022 SG’s 
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NIST OWM Executive Summary for EVF-23.6 – S.5.2. EVSE Identification and Marking 

Requirements and T.2. Tolerances

language did not include an exemption for DC systems from accuracy tolerances up 

through 2028 to sunset in 2034 and was a more suitable option.

o Recognized the EVFE Subgroup would further refine the requirement’s text. 

• OWM acknowledged a Florida, Electrify America, Tesla, EVgo, and Siemens’ October 15, 

2022, letter sent to the S&T Committee regarding EVF-23.6 and a June balloted proposal of 

the USNWG EVFE Subgroup (SG). OWM submitted the following clarifications regarding 

this letter to the S&T Committee.

o NIST OWM, as convenors of the EVFE SG, sent a response to the Committee indicating 

that although the results of the Subgroup’s June 2022 ballot indicate the group’s support 

for modifications to tolerances and marking requirements this should not be construed as 

supporting the specific changes proposed in EVF-23.6.

There are some key differences between the Subgroup’s June balloted proposal and EVF-23.6. 

Specifically, the Subgroup’s proposal does not include two different retroactive dates and 

differs in the magnitude of the tolerances and specific conditions under which they would 

apply, the permissible format required for markings (which are not indelible, do the submitters 

have a label or electronic only in mind?) and reference to certification. The convenors of the 

Subgroup will continue to provide written and verbal input as explicitly directed by the group.

Due to time constraints the Subgroup has not met on this issue in 2023.

• Should the community agree to the numerical designation of an Accuracy Class for DC 

systems which meet the wider tolerance, then additional requirements should be developed to 

include: (1) a new standardized accuracy class table; (2) requirements specifying the 

appropriate “Accuracy Class” identifier; and (3) requiring the accuracy classification be 

marked on the EVSE.

• Notice to consumers will need to adequate as to the information they provide that accuracy 

assurance varies from one site to another. 

Table 2. Summary of Recommendations

EVF-23.6 – S.5.2. EVSE Identification and Marking Requirements and T.2. Tolerances

Status Recommendation Note* Comments

Submitter Voting Recommending further modification

OWM Developing

Recommend deliberations on enforcement 

dates and establishing parameters for use of 

an electronic display

WWMA Developing

NEWMA Developing

SWMA Voting Recommend October 2023 modifications

CWMA Voting Recommend modifications
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NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Electric Vehicle Fueling Systems as follows:

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall have 

the following information conspicuously, legibly, and indelibly permanently marked:

(a) voltage rating;

(b) maximum current deliverable;

(c) type of current (AC or DC or, if capable of both, both shall be listed);

(d) minimum measured quantity (MMQ); and

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C (40 °F to + 185 °F).

S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior to 2024. – A DC EVSE

installed and placed into service prior to 2024 shall be marked with the following:

NOTICE:

“This charger operates at a tolerance of up to ± 5 percent versus other chargers

which operate at a maximum tolerance of up to ± 2 percent.”

This marking shall be conspicuously and legibly displayed in a position plainly visible to

a person accessing a charging port of the EVSE. The indicating element may be used to 

display this notice, provided the notice is presented to the customer prior to the beginning 

of the transaction. 

This marking requirement does not apply to DC EVSEs that are capable of meeting an 
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acceptance tolerance of ± 1 percent and a maintenance tolerance of ± 2 percent.

(Added 202X)

T.2. Test Tolerances

T.2.1. EVSE Load Accuracy Test Tolerances for AC Systems. – The tolerances for EVSE load 

tests for AC systems are:

(a) Acceptance Tolerance: 1.0 %; and

(b) Maintenance Tolerance: 2.0 %.

T.2.2. EVSE Load Accuracy Test Tolerances for DC Systems. -- The tolerances for EVSE 

load tests on DC systems shall be as follows:

(a) For DC systems installed and placed in service prior to January 1, 2024, and

that bear the notice specified in paragraph S.5.2.1. Marking of Accuracy Limits, DC

EVSEs installed and placed in service prior to 2024, acceptance and maintenance

tolerances are: 5.0 percent. This paragraph T.2.2(a) shall expire on January 1, 2034;

after that date, all DC EVSEs shall be subject to the tolerances of paragraph T.2.2(b).

(b) For DC systems installed and placed in service on or after January 1, 2024, or

that do not bear the notice specified in paragraph S.5.2.1. Marking of Accuracy 

Limits, DC EVSEs installed and placed in service prior to 2024 tolerances are:

(1) Acceptance Tolerance: 1.0 percent; and

(2) Maintenance Tolerance: 2.0 percent.

All DC EVSE are exempt from this requirement paragraph T.2.2 until January 1, 2028.

NIST OWM Detailed Technical Analysis: 

The proposal outlined in agenda item EVF-23.6 is not exactly the same as an alternative proposal the 

EVFE SG was working toward in the group’s June 2022 ballot of its voting membership. In the case of 

the EVFE Subgroup, the wider tolerance of 5 % for DC systems installed before 2024 was identified by 

several OEMs as achievable, and the less-than-ideal existence of dual tolerances in the marketplace would 

be addressed by marking the accuracy achievable by devices which met only the wider tolerance. 

Granted some refining of the requirement text would be necessary the group’s alternate proposal 

addressed many concerns expressed by both OEMs and regulators when the Subgroup’s discussions on 

this topic first began in 2020.

NIST OWM was made aware of an October 15, 2022 letter from Florida and industry representatives 

from Electrify America, Tesla, EVgo, and Siemens sent to the NCWM S&T Committee. The co-authors 

of the letter summarized the EVF-23.6 proposal recommendations. The co-authors stated their beliefs 

about their comparison of EVF-23.6 to the Subgroup membership’s June 2022 balloted proposal and the 

subgroup’s position on EVF-23.6. On October 20th NIST OWM as convenors of the USNWG EVFE 

Subgroup sent to the NCWM S&T Committee a written response to the October 15th letter to clarify 

references made that imply the EVFE Subgroup’s approval or support of S&T Agenda Item EVF-23.6. 
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Though the results of the Subgroup’s June 2022 ballot indicate the group’s support for modifications to 

tolerances and marking requirements was not to be construed as supporting the specific changes proposed 

in EVF-23.6. There were some key differences between the Subgroup’s June 2022 balloted proposal and 

EVF-23.6. Specifically, the Subgroup’s proposal did not include two different retroactive dates and 

differs in the magnitude of the tolerances and specific conditions under which they would apply, the 

permissible format required for markings, and had no reference to certification to the tighter of the dual 

tolerances. The convenors also clarified that the Subgroup would provide written and verbal input as 

explicitly directed by the group (outlined below in the section under the subgroup heading). 

The proposal in EVF-23.6 to include a new paragraph T.2.2. to address DC systems tolerances as worded

permits a 5 percent tolerance for EVSEs installed pre- or post- 2024 on the condition this accuracy is 

declared in a “NOTICE”; however, if not bearing a notice, then the expectation is that regardless of the 

installation date a DC system will still be permitted operation at the proposed maximum 5 percent 

accuracy. Device tolerances should not henge on the presence of a temporary label (i.e., the “Notice” for 

accuracy does not have to be indelible). Equipment has been permitted multiple accuracy classes; 

however, those devices bear an accuracy class marking permanently at all times and that determination is 

made during type evaluation of the device. However, in many device codes there is only a single 

accuracy class for vehicle refueling applications. 

Proposed new subparagraph T.2.2.(a) specifies a 2034 sunset date for equipment with a 5 percent 

accuracy this is almost two decades after the EVFS Code was published and becomes the second 

enforcement date included in the tolerance specification. The DC tolerance requirement also includes a 

2028 enforcement date proposed in July 2022 and then adopted in July 2022 as part of a priority item. 

That 2028 date appears as in the current handbook edition as an applicable enforcement date in Agenda 

Item EVF-23.6. This proposal attempts to address DC systems tolerances when they are exempt from 

handbook test tolerances until 2028. There appears to be mixed opinions on the service life of EVSEs 

installed up through December 31, 2023 which would contribute further to the confusion about timelines 

for phasing out noncompliant equipment. 

Moving forward with adoption before fully vetting proposals to modify fundamental requirements such as 

accuracy, transparency, or that ensure fair competition which are the foundation of every weighing and 

measuring device code can have unforeseen consequences. To delay or eliminate these basic guidelines 

(tools needed for this new device application) encourages nonuniformity (from state to state) which can 

be disruptive and impact the level of confidence in the marketplace. Proposals should be evaluated based 

on their impact on all stakeholders in the community. Time and again the community has moved to take 

corrective action on discovering an oversight that resulted from either the modification of existing or 

adoption of a new legal metrology requirement. It has been said when addressing the level of confidence 

that buyers and sellers have, and the accuracy with which these transactions are performed that: The 

consumer has no way to verify the accuracy of the transaction and must rely on the accuracy of the fuel 

dispenser.

NIST OWM encourages the community’s participation in the USNWG which began work in 2012 as a 

forum for stakeholders and other interested parties in establishing legal metrology standards (also the 

weights and measures infrastructure) for electrical energy measurements. That effort resulted in NIST 

HB 44 3.40 EVFS Code’s adoption in 2015. The four paragraphs that appear in multiple 2023 proposals 

address (1) dual EVSE tolerances (2.0 percent or 5.0 percent [DC EVSEs]); (2) new EVSE markings 

required for the wider tolerance in the marketplace (proposed new 5.0 percent accuracy for DC systems); 

and (3) corresponding accuracy test procedures are part of the EVFE SG’s meeting discussions. The 

EVFE Subgroup’s work continues having met October 6, 18, and December 8, 2022 and March 2 and 6, 

2023 to address proposals under consideration for the 2023 cycle. It should be noted that the EVFE SG 
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has worked to further refine the code as more is learned about these systems and since January 2020 met 

18 times to consider the proposals the group submitted to the S&T Committee as well as those developed 

or under development outside of its forum to provide the group’s input. The EVFE SG will provide a 

clear statement of its exact position on agenda proposals when it reaches a consensus and provides this 

information in writing. The EVFE SG in July 2022 gained momentum on moving forward to recommend 

a wider tolerance of 5 percent only for DC systems installed before 2024 that must bear accuracy 

markings while maintaining for AC systems a 1 percent Acceptance Tolerance/2 percent Maintenance 

Tolerance and the more stringent tolerances would also apply to pre 2024 DC system models designed to 

meet the tighter tolerances and all other post 2024 DC systems. Where commercial equipment is known 

to operate at dual tolerances the proposed marking and performance requirements should be retroactive. 

NIST OWM concurs with the NEWMA recommendation to make the proposal applicable to coincide 

with the 2024 date for the installation and commercial use for systems specified in EVF-23.6 and in light 

of the EVSE code’s adoption almost a decade ago in 2015. Use of the terms “load” and “accuracy” 

should be reviewed for consistency in their use in the titles of the two T.2. subparagraphs. The statement 

adopted by the NCWM in July 2022 exempting DC devices from any tolerance requirements until 2028 

remains in the proposal, yet there is a date of 2024 in both the proposed paragraph T.2.2.(a) and paragraph 

T.2.2.(b) which specifies requirements for DC devices installed prior to 2024. This is confusing and 

widens the gap: (1) in time delays in the application of tolerances in what will be a dual tolerance 

marketplace for DC systems (2) that encourages nonuniformity in equipment performance and (3) in the 

timely marking of information for consumer awareness. And the proposed sunset for equipment of 2034 

is 20 years after the code’s adoption.

NIST OWM acknowledges that the EVFE Subgroup met on December 8, 2022 and March 2 and 6, 2023 

to address proposals under consideration for the 2023 standards development cycle and the SG provided a 

July 12, 2023 memorandum on its position in support of the Item Under Consideration for Item EVF-23.6 

as it appears in the Committee’s Interim Meeting Report (NCWM Pub. 16). The SG has not had the 

opportunity to meet to discuss this item during the second half of 2023.

Should the community agree to the numerical designation of an Accuracy Class for DC systems which 

meet the wider tolerance, then additional requirements should be developed which address: (1) including 

a new standardized accuracy class table (i.e., Table XX. Accuracy Classes and Tolerances for Electric 

Vehicle Fueling Systems) in the code; (2) requirements specifying the appropriate “Accuracy Class” 

identifier for the accuracy class marking on the device to lessen the likelihood of this prefix being 

mistaken for representing alternating current (i.e., a proposed new subparagraph S.5.2.(f)(1)); and (3) 

requiring the accuracy classification be marked on the EVSE under a proposed new subparagraph to read: 

S.5.2.(f) EVSE Identification and Marking Requirements; Accuracy Class the accuracy class of the 

EVSE as specified by the manufacturer consistent with Table XX. Accuracy Classes and Tolerances for 

Electric Vehicle Fueling Systems in NIST Handbook 44, Section 3.40 Electric Vehicle Fueling Systems 

(Added 20XX). Commercial EVFSs are dissimilar in their design, relatively new to the marketplace, and 

used by customers who never encountered dual accuracy tolerances traditional fuel and alternative fuel 

dispensing systems. Notice to consumers will need to adequate as to the information they provide that 

accuracy assurance varies from one site to another.

U.S. National Work Group’s Electric Vehicle Fueling Equipment Subgroup (EVFE SG)

• The EVFE SG agreed to forward the results of its June 2022 ballot (in which it proposed changes 

to the tolerances and the addition of marking requirements) to the S&T Committee and 

recommend the Committee consider these recommendations as it considers Items EVF-23.5 and 

EVF-23.6.
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• In a June 2022 ballot, the SG agreed to recommend the following changes to the tolerances and 

marking requirements in Section 3.40 EVFS Code. The SG asked that the Committee consider 

the SG’s recommendations presented below as it deliberated on S&T Agenda Items EVF-23.5 

and EVF-23.6 which include proposed changes to these same handbook code paragraphs. The 

changes the SG was working towards in its June 2022 ballot are shown below.

o Additionally, some device users on the SG indicated that there remains a desire to recognize 

and then maintain a 5% tolerance for DC legacy (i.e., installed prior to 2024) equipment.

Proposal Balloted the June 2022 EVFE SG read:

T.2. Load Accuracy Test Tolerances.

T.2.1. EVSE Load Accuracy Test Tolerances for AC Systems. – The tolerances for EVSE 

load tests for AC systems areshall be as follows:

(a) Acceptance Tolerance: 1.0 %; and 

(b) Maintenance Tolerance: 2.0 %.

(Amended 202X)

T.2.2. EVSE Accuracy Test Tolerances for DC Systems. – The tolerances for EVSE load 

tests on DC systems shall be as follows:

(a) For DC systems installed prior to 2024 and that bear the notice specified in 

paragraph S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior to 2024, 

acceptance and maintenance tolerances are: 5.0 %.

(b) For DC systems installed on or after January 1, 2024 or that do not bear the notice 

specified in paragraph S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed 

Prior to 2024 tolerances are:

(1) Acceptance Tolerance: 1.0 %; and 

(2) Maintenance Tolerance: 2.0 %. 

(Added 202X)

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall 

have the following information conspicuously, legibly, and indelibly marked:

(a) voltage rating;

(b) maximum current deliverable;

(c) type of current (AC or DC or, if capable of both, both shall be listed);

(d) minimum measured quantity (MMQ); and

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C (− 40 °F to + 185 °F).
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S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior to 2024. – DC EVSEs 

installed prior to 2024 shall be marked with the following:

NOTICE:

“This charger operates at a tolerance of +/- 5 percent versus newer chargers which 

operate at a maximum tolerance of +/- 2 percent.”

This marking shall be conspicuously, legibly, and indelibly marked, in a position 

plainly visible to a person accessing a charging port of the EVSE.

This marking requirement does not apply to DC EVSEs that are capable of meeting 

an acceptance tolerance of 1 % and a maintenance tolerance of 2 %.

(Added 202X)

(Amended 2021)

A July 12, 2023 memorandum reported on the March 2, 2023 ballot results of 6 Public Sector and 7 

Private Sector members of the EVFE Subgroup resulting in 12 Approvals and 1 (Private Sector) vote in 

opposition to the Committee’s draft proposal for EVF-23.6 as it appears in the 2023 Interim Meeting 

Report (PUB 16). Voting results including all comments were made available May 5, 2023. Voting 

guidelines required 12 votes of approval from the 23 voting members on the subgroup roster. An April 6, 

2023 EVFE SG ballot on the recognition of a digital accuracy statement was not approved by the SG.

Summary of Discussions and Actions:

The submitters recently sent a letter dated May 8, 2023 to remind the Committee about a previous letter 

dated October 15, 2022 from the State Weights and Measures Director of Florida and industry 

representatives from Electrify America, Tesla, EVgo, and Siemens sent to the NCWM S&T Committee. 

The co-authors of the letter summarized the EVF-23.6 proposal’s recommendation for a 5 percent 

tolerance for DC systems installed before 2024 when so marked, if installed after 2024 or lacking the 5 

percent markings, those DC systems would be subject to 1 percent/2 percent tolerance. The Submitters 

noted the October 4, 2022 announcement by NIST of a general consensus on a June 2022 balloted 

proposal of the USNWG EVFE Subgroup (the ballot was an attachment to the submitters’ October 15th

letter). However, the submitters did not report the results of that ballot and it should be noted that the 

EVFE Subgroup vote did meet the threshold required to approve the June 2022 ballot. The Submitters’ 

response to the EVFE Subgroup member opposing the June 2022 proposal was to include a new 2034 

expiration on the 5 percent tolerance as part of the proposal in item EVF-23.6. The submitters stated their 

beliefs about their comparison of EVF-23.6 to the Subgroup membership’s June 2022 balloted proposal 

and the Subgroup’s 2022 position on EVF-23.6.

A letter dated October 20, 2022 from the NIST OWM as convenors of the USNWG EVFE Subgroup was 

sent to the NCWM S&T Committee in response to the October 15th letter co-authored by Florida, 

Electrify America, Tesla, EVgo, and Siemens. The letter was sent to clarify references made in the 

October 15th letter that imply the EVFE Subgroup’s approval or support of S&T Agenda Item EVF-23.6. 

Though the results of the Subgroup’s June 2022 ballot indicate the group’s support for modifications to 

tolerances and marking requirements this should not be construed as supporting the specific changes 

proposed in EVF-23.6. There are some key differences between the Subgroup’s June balloted proposal 

and EVF-23.6. Specifically, the Subgroup’s 2022 proposal did not include two different retroactive dates 

and differed in the magnitude of the tolerances and specific conditions under which they would apply, the 
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permissible format required for markings, and reference to certification. The convenors of the Subgroup

will continue to provide written and verbal input as explicitly directed by the group. 

In Conclusion: March 2023 deliberations of the EVFE SG resulted in a vote approving the proposal in 

Item EVF-23.6 as published in the 2023 NCWM Interim Meeting Report, followed by a July 12, 2023 

memorandum indicating the group’s support of the proposal being sent to the NCWM S&T Committee. 

The series of events that lead to this conclusion were as follows: The EVFE Subgroup met on December 

8, 2022, input based on the group’s discussions of S&T Item EVF-23.6 are provided above in the section 

of this analysis under the heading U.S. National Work Group’s Electric Vehicle Fueling Equipment 

Subgroup (EVFE SG). However, during the EVFE Subgroup March 2, 2023 meeting during its 

discussions on all S&T Agenda EVSE related proposals the Subgroup did vote to approve Item EVF-23.6 

with six Public Sector and seven Private Sector votes resulting in 12 Approving and one Opposing 

(Private Sector) the Committee’s March 2023 version of EVF-23.6. The 12 votes of approval from the 23 

voting members on the subgroup roster met the threshold of 12 for approval. The Subgroup 

acknowledged the Committee’s providing additional information in the accuracy notice statement to 

clarify the limits of the performance of unmarked DC systems is at a “maximum” tolerance of up to ± 2 

percent. At the conclusion of its March 6th meeting and discussions the EVFE Subgroup considered 

further modifications to proposed new paragraph S.5.2.1. to recognize accuracy markings in digital 

format. An April 2023 ballot on a digitally formatted accuracy marking statement resulted in six Votes 

[three Public/three Private] to Approve and six Votes [two Public/four Private] in opposition which did 

not meet the threshold (12 of 23 voting members) for the Subgroup’s approving further modification of 

EVF-23.6 at that time. The Weight and Measures Community during its Standards Development Process 

has previously considered proposals for presenting required marking information in a digital format; 

therefore, for everyone continuing on with the development of similar requirements it is suggested those 

national discussions be revisited along with reviewing the comments received in the April 2023 EVFE 

Subgroup ballot that recommended specifying a minimum time of 30 seconds for the duration of the 

displayed accuracy statement and the statement be viewed in entirety prior to use of the EVSE. 

At the 2023 NCWM Interim Meeting, the Committee considered the comments heard during open

hearings and has assigned a Voting status to the item. The Committee worked on modifying the item 

based on the comments heard during open hearings and written comments submitted by NIST OWM and 

CDFA DMS to include: 

• Further modifications by the Committee to proposed new paragraph S.5.2.1. Marking of 

Accuracy Limits, DC EVSEs Installed Prior to 2024 included:

- eliminating the exemption for marking accuracy levels for EVSEs that hold an unspecified 

certification by removing the text “unless it is certified to the tolerances of T.2.2(b)” from the 

paragraph:

- specifying in the accuracy notice statement that the EVSEs marked 5 percent tolerance are in 

contrast to all “other” unmarked systems operating at more stringent tolerances which 

resulted in the removal of any reference to “newer” charging equipment.

- providing more information about the accuracy limits of DC EVSEs that meet the 2 percent 

tolerance by specifying these systems operate at a “maximum” tolerance of up to ± 2 percent.

Additionally, the Committee modified the conditions for displaying the accuracy markings in paragraph 

S.5.2. EVSE Identification and Marking Requirements by removing the term ”indelibly” and specifying 

this information must be “permanently” marked.
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In proposed new paragraph S.5.2.1. and paragraph T.2.2. EVSE Load Accuracy Test Tolerances for DC 

Systems the Committee further clarified that this set of requirements apply to DC systems installed prior 

to January 1, 2024 and to include the text that further quantifies that point in time as when the equipment 

has been “placed into service” prior to January 1, 2024.

At the 2023 NCWM Annual Meeting, the Committee considered comments from the floor and modified 

the item to match that proposed by the CWMA to include additional wording in proposed new paragraph 

S.5.2.1. that reads “The indicating element may be used to display this notice, provided the notice is 

presented to the customer prior to the beginning of the transaction.” to recognize a digitally formatted 

display of the accuracy statement notice. The Committee agreed to make the item voting not changing 

any dates in the proposal. The item did not receive enough votes to pass or fail. The item was returned to 

Committee. 

Regional Association Reporting:

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, ScheLeese Goudy (Electrify America) remarked a DC EVSE 

installed before 2024 will have 5 % accuracy until 2034. When the tentative code was written in 2015, 

historical data for AC measurements were readily available. DC metering technology was still in R&D. 

Tolerances could not be formulated. Legacy devices could reasonably meet 5 %, but not 1 %/2 %. This 

could require complete replacement of many legacy devices.

Francesca Wahl (Tesla) remarked rework of two above. Does not modify the 2028 date but provides a 

pathway forward. This proposal represents informal consensus of the NIST USNWG.

Craig VanBuren (Michigan) recommended the proposal move forward as Voting. Possible change: P 

244, line 39. which “may” operate.

The CWMA S&T Committee believed this item is fully developed and recommended Voting status with 

the following changes:

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall have 

the following information conspicuously, legibly, and indelibly marked:

(a) voltage rating;

(b) maximum current deliverable;

(c) type of current (AC or DC or, if capable of both, both shall be listed);

(d) minimum measured quantity (MMQ); and

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C ( 40 °F to + 185 °F).

S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior to 2024. – A DC EVSE 

installed prior to 2024 shall be marked with the following unless it is certified to the 

tolerances of T.2.2(b):
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NOTICE:

“This charger operates at a tolerance of up to ± 5 percent versus other chargers which 

may operate at a tolerance of up to ± 2 percent.”

This marking shall be conspicuously and legibly displayed in a position plainly visible to 

a person accessing a charging port of the EVSE.

(Added 202X)

T.2. Test Tolerances.

T.2.1. EVSE Load Accuracy Test Tolerances for AC Systems. – The tolerances for EVSE load 

tests for AC systems are:

(a) Acceptance Tolerance: 1.0 %; and

(b) Maintenance Tolerance: 2.0 %.

T.2.2. EVSE Load Accuracy Test Tolerances for DC Systems. – The tolerances for EVSE load 

tests on DC systems shall be as follows:

(a) For DC systems installed prior to January 1, 2024, and that bear the notice specified in 

paragraph S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior to 2024, 

acceptance and maintenance tolerances are: 5.0 %. This paragraph T.2.2(a) shall 

expire on January 1, 2034; after that date, all DC EVSEs shall be subject to the 

tolerances of paragraph T.2.2(b).

(b) For DC systems installed on or after January 1, 2024, or that do not bear the notice 

specified in paragraph S.5.2.1. Marking of Accuracy Limits, DC EVSEs Installed Prior 

to 2024 tolerances are:

(1) Acceptance Tolerance: 1.0 %; and

(2) Maintenance Tolerance: 2.0 %.

All DC EVSE are exempt from this requirement paragraph T.2.2 until January 1, 2028.

At the 2023 CWMA Annual Meeting, ScheLeese Goudy stated the EVFE Subgroup approved this change 

and had no objection to digital display. The 2028 exemption was just voted and approved at NCWM. If 

moved to 2024, there is no adequate test equipment to test DC chargers. A recent demonstration of a 

tester did not function correctly for DC testing. If the exemption date moves up, states would have to 

write policies to exempt devices?

Jared Ballew (ChargePoint) indicated the original intent was to display the notice digitally or physically. 

And has concern that current wording does not make it clear that digital display of the notice is 

acceptable. Retrofitting existing equipment with physical markings would be cost prohibitive. And then 

the same when the notice is removed in the future. He does not support proposal without the clear 

allowance for digital display. No problem with moving the date to 2024, they’ve known this tolerance 

expectation for years. But agrees that the availability of (lack of) test equipment, would cause a problem.
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Loren Minnich (NIST OWM) indicated NIST OWM would recommend that the S&T Committee provide 

guidance on the intent and implementation of three enforcement dates in proposed new paragraph T.2.2. 

EVSE Load Accuracy Test Tolerances for DC Systems to ensure regulators, the service industry, EVSE 

and test equipment manufacturers, and operators can smoothly transition equipment into commercial use 

and eventually meet the tighter tolerance. This is more important because the exemption granted for “All 

DC EVSE“ tolerances until January 1, 2028 remains in code paragraph T.2. creating a four-year gap that 

impacts the proposed new dual tolerance system (i.e., the straightforward application of two separate 

tolerances from a pre2024 and post 2024 generation of equipment standpoint). The 2028 enforcement 

date is a sharp contrast to the enforcement dates prescribed in the submitters’ first statement on their 

purpose for the proposal of creating “1 % (acceptance) / 2 % (maintenance) tolerances would apply to 

devices installed after January 1, 2024. For devices installed before that date, the tolerances would be 5% 

(acceptance and maintenance).” The tracking of equipment is critical and may require more work 

because locations are obscure and not attended (requiring more investigative work to communicate with 

the operator and billing agent) also since placed in service policies vary from jurisdiction to jurisdiction. 

At the NEWMA Regional Meeting a proposal was made and adopted to recommend the January 1, 2028 

date be amended to January 1, 2024. If accepted by the NCWM S&T Committee the earlier date could 

eliminate the potential confusion in the implementation of this requirement. This would allow each 

jurisdiction the discretion to implement these accuracy requirements as test equipment becomes available 

to place devices into service. This would eliminate the current exemption from any tolerances for DC 

systems and would provide industry with firm requirements on which to base test equipment capabilities 

and EVSE devices capable of meeting these requirements. There would still be two sets of tolerances 

based on the date of installation, prior to January 1, 2024 and after January 1, 2024 depending on 

equipment capability or markings as described in paragraph S.5.2.1. Marking of Accuracy Limits, DC 

EVSEs Installed Prior to 2024.

Monica Martinez (Tesla) supports voting and this is important to address new technology. Support the 

idea of digitally and agree as long as voting in July is preserved. The 2028 exemption is the same that 

was voted on at NCWM. No evidence that anything has changed to warrant the exemption date being 

moved (testing equipment still not available).

Craig VanBuren does not support changing date from 2028. Supports digital allowance if it says the 

notice must be displayed prior to the transaction.

The Committee recommends this item remain voting status with the following change to S.5.2.1. (S&T –

353, Lines 4 and 5:

This marking shall be conspicuously and legibly displayed in a position plainly visible to a person 

accessing a charging port of the EVSE. The indicating element may be used to display this 

notice, provided the notice is presented to the customer prior to the beginning of the transaction.

At the CWMA 2023 Interim Meeting the following comments were received:

ScheLeese Goudy from Electrify America presented on this item. ScheLeese recommends this as a 

voting item with revisions. Mike Harrington (Iowa) supports item with changes and that we should 

not put accuracy markings regarding tolerances on the meter because we might need to then do that 

for all devices. Tolerances are currently public information and consumers can find them if needed. 

Accuracy Class marking will help inspectors know what tests/tolerances to apply and should be on 

the devices. Mike supports this item as voting. Greg VanderPlaats (Minnesota) supported this item at 

the 2023 NCWM Annual Meeting. The language in this updated proposal is better than the previous 
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version. Greg supports as a voting item. The Committee recommends this item as a voting item with 

the following changes: 

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall 

have the following information conspicuously, legibly, and indelibly permanently marked: 

(a) voltage rating; 

(b) maximum current deliverable; 

(c) type of current (AC or DC or, if capable of both, both shall be listed);

(d) minimum measured quantity (MMQ); and 

(e) temperature limits, if narrower than and within – 40 °C to + 85 °C (− 40 °F to + 185 °F). 

S.5.2.1. Marking of Accuracy Class, DC EVSEs Placed in Service Prior to 2024. – A 

DC EVSE that was placed into service prior to 2024 and is subject to the tolerances of 

T.2.2(a) is an accuracy Class 5 EVSE and shall be marked with Class 5. The marking 

shall be conspicuously and legibly displayed in a position plainly visible to a person 

accessing a charging port of the EVSE. The indicating element may be used for the 

marking, provided the marking is visible to the customer prior to the beginning of the 

transaction.

(Added 202X)

T.2. Test Tolerances. 

T.2.1. EVSE Load Accuracy Test Tolerances for AC Systems. – The tolerances for EVSE 

load tests for AC systems are:

(a) Acceptance Tolerance: 1.0 %; and 

(b) Maintenance Tolerance: 2.0 %. 

T.2.2 EVSE Accuracy Test Tolerances for DC Systems. -- The tolerances for EVSE load 

tests on DC systems shall be as follows: 

(a) For a DC system that was placed in service prior to January 1, 2024, and that is 

marked Class 5, acceptance and maintenance tolerances are: 5.0 %. This paragraph 

T.2.2(a) shall expire on January 1, 2034; after that date, all DC EVSEs shall be 

subject to the tolerances of paragraph T.2.2(b). 

(b) For any DC system not subject to paragraph T.2.2(a), tolerances are:

(1) Acceptance Tolerance: 1.0 %; and 

(2) Maintenance Tolerance: 2.0 %. 

All DC EVSE are exempt from this requirement until January 1, 2028.
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Western Weights and Measures Association

During the WWMA 2022 Annual Meeting the following comments were received:

ScheLeese Goudy commented on the metering technology for DC chargers are now becoming available 

as technology develops. ScheLeese Goudy proposed previously installed devices will not be able to meet 

the 1 % and 2 % tolerances. ScheLeese Goudy commented the tolerances are being developed with 

separate tolerances for legacy devices that can’t meet the proposed requirements. ScheLeese Goudy 

stated there was a vote of 11 to 1 in favor of the item in the assigned work group. The one no vote said 

that it would have been a yes if there was a 10-year sunset. ScheLeese Goudy stated the changes to the 

item incorporated the change to include a 10-year sunset of legacy devices. ScheLeese Goudy 

commented devices would be marked for the public and inspectors with the required tolerances. 

ScheLeese Goudy recommended Voting status.

Kevin Schnepp (California Division of Measurement Standards) commented this was discussed in the 

national workgroup. Kevin Schnepp recommended that a task group be assigned to verify which items 

were in a consensus and which were not. Kevin Schnepp proposed a hard stop date for legacy devices is 

necessary and that there isn’t one with the current language. Kevin Schnepp commented on his 

disagreement with the "or" statement in the current language.

Francesca Wahl (Tesla) commented they agree with the comments made by Electrify America. Francesca 

Wahl commented the language is to include a hard stop date of legacy devices supports the removal of 

“or” from the language.

Chris King (Siemens) commented Siemens agrees with Tesla’s comments.

During open hearings, comments were heard that contents in this item were previously discussed in the 

USNWG, but no official position has been taken by the USNWG. There were also comments during 

open hearing taking the position the item is not fully developed. The WWMA S&T Committee 

recommended the submitters work with the USNWG to develop one proposal by combining language 

from EVF-23.5.

The WWMA S&T Committee recommended that this item be blocked with item EVF-23.5. The WWMA 

S&T Committee recommended the new blocked items be assigned a Developing status. The WWMA 

S&T Committee recommended that this item be blocked with item EVF-23.5. The WWMA S&T 

Committee recommended the new blocked items be assigned a Developing status.

During the WWMA 2023 Annual Meeting updated language to this item was provided to the WWMA 

S&T Committee and posted to the WWMA website at: {Events – Meeting Documents – EVF-23.6 

Proposal}. A presentation was given by the submitters of this item. The submitters spoke to: (1) 5 % 

tolerance for legacy devices and (2) Marking requirement of Class 5 based on comments received during 

the 2023 NCWM Annual Meeting. General comments from industry supported a Voting status with the 

updated language. Kevin Schnepp (California, Division of Measurement Standards) supports this item 

with a recommended revision of the Exemption Date from 2028 to 2025. Mahesh Albuquerque 

(Colorado, Division of Oil and Public Safety) supports this item as Voting status. Comments from 

regulatory officials were heard regarding the concern of the language “placed into service” and the 

removal of the language of “Install” with the potential effect to “legacy devices” being used in the 

marketplace. Lenny Vang (EV Testing Solutions) questioned where the data on the 5% tolerance resulted 

from and requested from the submitter the data to justify the 5% tolerance. ScheLeese Goudy (Electrify 

America) clarified that the tolerances were aligned originally with California standards and existing 
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devices in use. Questions were raised about whether the marking requirement of “Class 5” if fully 

informative to a consumer. 

The WWMA 2023 S&T Committee recommends this item be assigned a Developing status with the

recommendation the submitter consider comments heard on the floor. The Committee notes there are two 

items on the 2023 WWMA S&T agenda that propose changes to section T.2 Load Test Tolerances (also 

see EVF-24.2). Updated language will be included in the WWMA S&T Committee 2023 Final Report as 

an Appendix to the item.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Hal Prince (Florida) spoke in favor of this item being a satisfactory 

compromise. Paul Floyd (Louisiana) would rather not have devices with warning labels for accuracy.

ScheLeese Goudy recommended this move forward as a Voting Item. John Stokes (South Carolina) 

stated they supported the use of warning labels for these devices and supported this item.

The SWMA S&T Committee recommended this item move forward as a Voting Item.

At the 2022 SWMA Annual Meeting, Paul Floyd, Louisiana, supports the revised item. ScheLeese 

Goudy gave a presentation of this item and supports the revision along with the other submitter and 

requests the NCWM S&T committee revise the item to the included language. She also stated the 5% 

tolerance because the 2% tolerance is unobtainable for legacy devices. She suggested the date change 

2028 to 2025 remain a separate item. ScheLeese Goudy also stated that industry would roll out the 

marking requirements via the indicating element. Mauricio Meija (Florida) supported this item. Tim 

Chesser (Arkansas) supported this item. Steve Benjamin (North Carolina) stated support for this item. 

John Stokes (South Carolina) asked whether jurisdictions had considered treating EVF as a service rather 

than a motor fuel. Tim Chesser responded to John Stokes that Arkansas views it as both, and both would 

fall under Weights and Measures jurisdiction. Paul Floyd (Louisiana) responded to John Stokes, that 

Louisiana has redefined retail electricity meters as a commercial weighing and measuring device. Alex 

Beaton (EVgo) stated that they will work hand in glove with the manufacturer to make adding the 

marking requirement seamless and requested a voting status for the item. Juana Williams (NIST OWM)

stated that that NIST has some concern that the use of multiple dates will cause confusion and cautioned 

moving forward without considering past discussions on digital markings. Perry Lawton (TESCO)

supported changing the date from 2028 to 2025.

The Committee recommends the following language as a replacement for the above item:

S.5.2. EVSE Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10. General Code, paragraph G-S.1. Identification, each EVSE shall have 

the following information conspicuously, legibly, and permanently indelibly marked: 

(a) voltage rating; 

(b) maximum current deliverable; 

(c) type of current (AC or DC or, if capable of both, both shall be listed); 

(d) minimum measured quantity (MMQ); and 
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(e) temperature limits, if narrower than and within –40°C to +85°C (40 F to +185°F). 

S.5.2.1. Marking of Accuracy Class, DC EVSEs Placed in Service Prior to 2024. – A DC 

EVSE that was placed into service prior to 2024 and is subject to the tolerances of T.2.2(a) 

is a Class 5 EVSE, and shall be marked with Class 5. The marking shall be conspicuously 

and legibly displayed in a position plainly visible to a person accessing a charging port of 

the EVSE. The indicating element may be used for the marking, provided the marking is 

visible to the customer prior to the beginning of the transaction.

(Added 202X) 

T.2. Load Accuracy Test Tolerances. 

T.2.1. EVSE Load Accuracy Test Tolerances for AC Systems. – The tolerances for EVSE load 

tests for AC systems are: 

(a) Acceptance Tolerance: 1.0 %; and 

(b) Maintenance Tolerance: 2.0 %. 

T.2.2. EVSE Accuracy Test Tolerances for DC Systems. – The tolerances for EVSE load tests 

on DC systems shall be as follows: 

(a) For a DC system that was placed in service prior to January 1, 2024, and that is marked 

Class 5, acceptance and maintenance tolerances are: 5.0 %. This paragraph T.2.2.(a) 

shall expire on January 1, 2034; after that date, all DC EVSEs shall be subject to the 

tolerances of paragraph T.2.2(b). 

(b) For any DC system not subject to paragraph T.2.2(a), tolerances are: 

(1) Acceptance Tolerance: 1.0 %; and 

(2) Maintenance Tolerance: 2.0 %. 

All DC EVSE are exempt from this requirement until January 1, 2028.

The Committee recommends this item move forward as a Voting item using the above language.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, Keith Bradley (Electrify America) recognizes that when the code 

was originally adopted there were questions about DC meters being able to meet a 1 % and 2 % tolerance. 

This item is to make sure devices are properly marked for the consumer as installed before 2024 and 5 % 

tolerance. If devices are not marked this way, the 1 % and 2% tolerances would apply. Installed devices 

would have the larger tolerance until 2034, then revert. Francesca Wahl recommends Voting status. 

Juana Williams (NIST OWM) noted that there is a letter from NIST to indicate that a status update on this 

item is forthcoming and has info to address marking and tolerances for DC systems. In a June meeting by 

the EVSE Subgroup, there was no 2028 retroactive date being considered and the proposal they reviewed 

included different sets of tolerances and marking requirements based on install date. Jason Flint (New 

Jersey) requested that this item be given a Developing status as there is too much debate and too many 
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questions. Jason Flint suggested that the submitters of Items EVF-23.5 and EVF-23.6 work together to 

develop further.

After hearing comments from the floor, the Committee believes the item is not fully developed and 

several questions need to be answered. The Committee is recommending that this item be given a 

Developing status.

At the 2023 NEWMA Annual Meeting, ScheLeese Goudy provided a letter from the submitters and 

supports as voting. Alicia Artessa (Tesla) supports as voting. Jared Ballew did not support the item as 

currently drafted, only with minor modification to paragraph S.2.5.1, as follows: “This marking shall be 

conspicuously and legibly displayed in a position plainly visible to a person accessing a charging port of 

the EVSE. The indicating element may be used to display this notice, provided the notice is presented to 

the customer prior to the beginning of the transaction.” 

He believes the original intent of the proposal was that the notice would be available digitally. Loren 

Minnich (NIST OWM) indicated that the NCWM S&T Committee should provide guidance on 3 

different dates listed in the proposal. ScheLeese Goudy supports ChargePoint’s proposal of modifying 

the language in paragraph S.2.5.1.

After hearing comments from the floor, the Committee recommended to the body that this item maintain 

a voting status with no changes. However, during discussion, Lou Sakin (Hopkinton, Massachusetts) 

requested that the date pertaining to DC EVSE be changed from 2028 to 2024. Lou Sakin stated that at 

the time the EVSE code became permanent in July 2022, testing equipment was not readily available to 

DC chargers, however, it has been demonstrated that the equipment is now available and enforcement 

agencies should have the ability to use it to enforce the tolerances. A suggestion was made by Ethan 

Bogren (Westchester County, New York) to change the date to 2025. ScheLeese Goudy disagrees that 

the technology is not available yet and does not support changing the date. Support for changing the date 

to 2024 was heard from Lou Sakin, James Cassidy (Massachusetts), Walt Remmert (Pennsylvania), Jim 

Willis (New York), Cheryl Ayer (New Hampshire), and Jared Ballew (ChargePoint).

After hearing discussion, the body voted to recommend to the NCWM S&T Committee to maintain a 

voting status with the following further changes to the current last sentence in T.2. Load Test Tolerances 

which applies to DC EVSEs to read:

All DC EVSE are exempt from this requirement paragraph T.2.2. until January 1, 2028.

At the 2023 NEWMA Interim Meeting, a presentation was given by a representative from Electrify 

America which described that this proposal would create a Class 5 EVSE device, which would alleviate 

concerns of having a tolerance percentage on the face of the device and requested a voting status. 

Regulators from the Commonwealths of Pennsylvania, Massachusetts, Vermont, and New Jersey support 

the changes as they would address the legacy devices. A regulator from the State of New Hampshire 

commented that there are concerns with “placed in service” vs “installed”. When something is placed in 

service, it may have been installed 10 years prior. A regulator from Holliston, Massachusetts questioned 

if the 2034 date is more of a convenience of manufacturers or a benefit to consumers and how are they 

supposed to know what a Class 5 means. They also questioned if the number is to be in Arabic or Roman 

numeral form. Regulators from the New York commented that they have the same concerns as New 

Hampshire. They prefer installed date, not placed in service, do not think Class 5 is transparent to 

consumers, and questioned if it should be a user requirement instead of design requirement. Upon 

consensus of the body, the Committee recommends this item be Developing.
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EVF-23.7 D N.1. No Load Test, N.2. Starting Load Test, N.5.2. Accuracy Testing, and 

Appendix D: Definitions – maximum deliverable amperes

Source: Electrify America

Submitter’s Purpose and Justification:

The proposal would have the testing conducted at the contemplated 10 %. Because it is unlikely that tests 

would actually be at precisely 10 %, the proposal would allow testing in a small range slightly above 

10 %. 

The accuracy tests in Section 3.40 contemplate testing an EV charger at two points, one at relatively low 

current and power, and the other at relatively high current and power. The low point was evidently 

intended to be at 10 % of a charger’s maximum current. It is likely that charger manufacturers have 

designed chargers with that 10 % in mind as the “low” point of accuracy tests. But the code does not 

actually state that testing should be at 10 %. It says testing can be at a current less than 10 %. This 

formulation is problematic because it encompasses any current less than 10 %. Zero is less than 10 %, 

and 0.1 A is less than 10 % even though it is less than the amount at which the code requires a charger to 

first register a load. Even currents larger than these, but less than 10 %, would be unnecessarily difficult 

for an accuracy test. The problem is that low currents are an area where accuracy is particularly difficult.

For example, one common metering configuration is to measure the current being delivered by means of a 

shunt resistor, which generates a voltage from the high current passing through it. These resistors 

necessarily have very low resistances because they are necessarily dissipating power in accordance with 

the resistance. A typical resistor in an EV charger metering setup might be 100 micro-ohms. For a 500 

amps full-scale current in a DC charger, that resistor would be dissipating 25 watts of power - thus, a 

much larger resistor is not a practical option. At, say, 10 amps of delivered current, the voltage generated 

across the resistor would be 1 millivolt. A 1 % measurement of that 1 millivolt would be 10 microvolts.

At that level, a range of noise sources become quite significant, such as thermal EMF in the resistor itself 

and induced EMFs from the presence within the charger cabinet of voltages up to 480 volts ac or 950 

volts dc, as well as any offsets or noise in the circuitry measuring the transduced voltage. The net result is 

that it is very challenging to achieve high accuracy at low currents in a device designed to handle and 

measure high currents. For reasons like these, the draft international (OIML) standard specifies that an 

accuracy test should be conducted at a given minimum current, rather than (like current Handbook 44) at 

any current up to that minimum. 

Meanwhile, low currents are the levels least significant for transactional accuracy. At low current, a 

charger is delivering energy at a relatively low rate. As a practical matter, an EV will charge at the 

maximum rate possible in the circumstances. As the battery reaches a higher state of charge, it will draw 

less power from the EV, but only a small proportion of the overall energy will be delivered at low rates, 

precisely because the rates are low. Suppose as a simplified example, an EV charges for 30 minutes at 

300 amps and 30 minutes at 15 amps (at a voltage of 400 volts). The EV will have received 60 kWh in 

the first part of the session, and only 3 kWh in the second part. The low-current period of charging 

contributes relatively little to the accuracy/inaccuracy of the overall transaction. 

Thus, it is important for Handbook 44 to set a minimum current for accuracy tests. Because the point of 

10 % of the maximum deliverable amperes is already in the code and has probably been used as a design 

basis for chargers, the proposal would keep that as the low-current point. The overall concept would be 

for testing to occur at 10 % of maximum deliverable amperes, rather than at up to 10 %. But it is 

impractical to specify a single point. An inspection that does not achieve a test at precisely the 10 %
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should not, as a consequence, be an invalid inspection. To make this practical, the proposal would have 

the low-end test occur in a range of currents, namely 10 % to 20% of the charger’s maximum. 

The code presents a similar problem for DC chargers tested using EVs as loads. The code allows an EV 

to be used as the load, rather than using a controlled load that draws the loads specified in the code. But 

the code provides no specifications about how to use an EV in this sort of test. So, it is possible that a 

tester could use an EV that is, say, at 95% state of charge in the battery, and that would arrive at the 

charger and draw very low levels of current (sometimes called a “trickle charge”). For the reasons 

discussed above, that sort of test would not be a productive test of the meaningful accuracy of the charger.

The code should set a minimum current for an EV-based test to be usable. The proposal would have that 

minimum be 30% of the charger’s maximum. It is set at more than 10 % because the EV-based test uses 

a single test point, which should therefore be somewhere in the middle of the charger’s range. 

The proposal would also add a definition of “maximum deliverable amperes.” This quantity is the same 

as used in the existing code as the basis for the 10 % figure, but it is not currently defined. The definition 

would state that maximum deliverable amperes means the amount marked on the charger. (The code 

already requires that amount to be marked.) This amount might be less than the manufacturer’s 

specification for the potential maximum of the device, if for example the installation limits the charger to 

a particular amount, or the installer has selected a configuration with a lower maximum. But the 

maximum deliverable amount is a quantity that is fixed at installation and marked on the charger. The 

current code suggests that maximum deliverable amperes is the amount that the charger communicates to 

a vehicle or test apparatus. That approach is confusingly ambiguous, because the charger might for 

various reasons sometimes communicate a lower available current than its marked maximum. The 

proposal clarifies that for accuracy tests based on a percentage of maximum current, the “maximum” 

being used is the maximum marked on the device.

These concepts have been discussed in the U.S. National Work Group’s Subgroup on EV charging. 

There is general consensus in favor of the proposal, but there has not been a quorum to vote formally in 

favor of it. 

Finally, the proposal would eliminate the no-load and starting-load tests. These tests take unnecessary 

time, because an inspector has to wait to verify that a load of zero genuinely produces no response and a 

starting load of just 0.5 amps produces a response. Meanwhile, these tests are not meaningful for the 

transactional accuracy of an EV charger. In the process of establishing a handshake that the EV charger 

is connected to a vehicle, the charger might provide minute test amounts of current, so that a truly zero 

load is not pertinent to any real transaction; and these minute test currents may well be above 0.5 amps, 

so that this threshold is also not pertinent to transactions. It would be possible to verify that a charger 

does not register an energy delivery when no transaction is started, but that test would be redundant of 

verifying that the charger starts at zero. Meanwhile, 0.001 kWh (the minimum resolution under 

Handbook 44) corresponds to roughly 3 to 5 hundredths of a cent, so that verifying the registration of 

such tiny amounts given a tiny current is not helpful for the overall transactional accuracy.

The submitter is not aware of objections that would be raised to this proposal. The concept is consistent 

with the discussions at the U.S. National Work Group based on information from testing over the past six 

years, and input from regulators and industry.

The submitter requested that this be a Voting Item in 2023.
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NIST OWM Executive Summary for EVF-23.7 – N.1. No Load Test, N.2. Starting Load Test N.5.2. 

Accuracy Testing, and Appendix D: Definitions– maximum deliverable amperes

NIST OWM Recommendation: Withdraw due to work in progress nearing completion to incorporate 

this proposal into EVF-23.7.

• Test procedures are not solely written to the operational characteristics or particular design of 

one test apparatus. Test procedures should encompass operational conditions over the course 

of the entire transactions in the marketplace. Test points should fall within the rated minimum 

up through the maximum operational ranges specified by the manufacturer for the EVFS under 

normal conditions of commercial use. 

• Observe this proposal removes any reference to the feature used to determine the MDA 

percentage level achieved during accuracy tests and establishes a new MDA range for 

performing the light load test and when a vehicle is the test load for verifying EVFSs; whereas 

other proposals recommend the establishment of a new laboratory test in addition to field test 

procedures.

• The EVFS test standard must be fit for purpose or appropriate and suitable (this might be 

demonstrated by data) in its design, capacity, and accuracy; and would allow for replication of 

the manner in which the EVSE is used in commerce. The test standard used to verify an EVSE 

must also meet the NIST HB 44 Appendix A Fundamental Considerations for a test apparatus. 

• Therefore, with a decade of experience with EVFSs having gone through type evaluation (i.e., 

CADMS) and test equipment designed to verify both AC and DC systems and the laboratory 

community closing in on filling the last gaps in the weights and measures infrastructure for 

EVFSs; it is important and necessary that all stakeholders (EVSE/test equipment 

manufacturers, type examiners, and regulators) reach a consensus on test procedures. 

• Is this a proposal to renumber paragraph N.5. Accuracy Testing to become N.5.2.1.? The 

proposal does not show paragraph N.5.2 in entirety, is the submitter proposing to remove the 

2028 enforcement date? Please be advised that as a result of actions which occurred during the 

31JUL2023-03AUG2023 NCWM Annual Meeting modifications to NIST HB 44 3.40 were 

adopted and resulted in the renumbering of the test notes (N.), the N.5 test procedure 

paragraphs were renumbered to become N.3. Additionally, that action by the NCWM deleted 

and no longer recognizes paragraphs N.1. No Load Test and N.2 Starting Load Test as part of 

the minimum test procedures for EVSEs. 

• The proposal removes the No Load Test and Starting Load Test but does not do the same for 

the tolerances applicable to these tests in paragraphs T.5. and T.6, respectively. 

• For clarity the “meaning portion” of a definition should not include the term or parts of the 

term it is defining nor cite one of the many code paragraphs where the term is used because the 

appearance can be the term is unique to that sole paragraph. Therefore, the term’s definition 

should include reference to the EVFS Code in brackets (i.e., [3.40] at the end of the definition 

rather cite a single code requirement or paragraph. The EVFS is a permanent code and 

definitions applicable to the code should be included in Appendix D—Definitions. 

• In May 2023 the EVFE Subgroup’s Test Procedures Subcommittee (TPS) was tasked with 

working through a May 2023 version of the test procedures addressed in Item EVF 23.4. This 
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NIST OWM Executive Summary for EVF-23.7 – N.1. No Load Test, N.2. Starting Load Test N.5.2. 

Accuracy Testing, and Appendix D: Definitions– maximum deliverable amperes

latest modified version of the test procedures is the result of the collaborative effort of the 

submitters of both test procedure proposals in Items EVF 23.4 and EVF-23.7. TPS discussions 

about modifications of the test procedures and defining new terms having special and openended meaning were focused on input from stakeholders (type and routine field testing), the 

NCWM, regional weights and measures associations, and NIST OWM. Based on the TPS's 

May through December 2023 deliberations the TPS has agreed to forward a combined proposal 

derived from both EVF-23.4 and EVF-23.7 for the EVFE Subgroup’s consideration.

Table 2. Summary of Recommendations

EVF-23.7 – N.1. No Load Test, N.2. Starting Load Test N.5.2. Accuracy Testing, and Appendix D: 

Definitions– maximum deliverable amperes

Status Recommendation Note* Comments

Submitter Voting

OWM Withdraw

See EVF-23.4 which combines text from

EVF-23.7 as part of an ongoing effort to 

merge both proposals within the 2024 cycle

WWMA Withdraw

NEWMA Withdrawn

SWMA Withdrawn

CWMA Voting Same proposal as shown in EVF-23.4

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44 Electric Vehicle Fueling Systems Code as follows:

N.1. No Load Test.– A no load test may be conducted on an EVSE measuring system by

applying rated voltage tothe system under test and no load applied.
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N.2. Starting Load Test. – A system starting load test may be conducted by applying rated

voltage and 0.5-ampereload.

...

N.5.2.1. Accuracy Testing. – The testing methodology compares the total energy delivered in a 

transaction andthe total cost charged as displayed/reported by the EVSE with that measured by

the measurement standard.

(a) For AC systems:

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a 

total energy delivered of at least twice the minimum measured quantity (MMQ). If 

the MDA would result in maximum deliverable power of greater than 7.2 kW, then

the test may be performed at 7.2 kW.

(2) Accuracy test of the EVSE system at a load of not greater thanbetween 10 % and 

20%of the maximum deliverable amperes (expressed as MDA) as determined 

from the pilot signal for a total energy delivered of at least the minimum measured

quantity (MMQ).

(b) For DC systems (see note):

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes current (expressed as MDA) as determined from the digital 

communication message fromthe DC EVSE to the test standard for a total energy

delivered of at least twice the minimum measuredquantity (MMQ).

(2) Accuracy test of the EVSE system at a load of not more than 10 % and 20% of the 

maximum deliverable amperes (expressed as MDA) as determined from the 

digital communication message from the DCEVSE to the test standard for a total 

energy delivered of at least the minimum measured quantity (MMQ).

Note: For DC systems it is anticipated that an electric vehicle may be used as the test load. Under that

circumstance, testing at the load presented by the vehicle shall be sufficient provided that it is greater than

30% of the maximum deliverable amperes of the EVSE system.

(Amended 20XX)

And

Appendix D:

maximum deliverable amperes. – The value in amperes, marked on an EVSE pursuant to 

paragraph S.5.2. EVSE Identification and Marking Requirements, of the maximum current that

the EVSE can provide.

(Added 20XX)

NIST OWM Detailed Technical Analysis: 
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There are other 2023 proposals on the S&T Committee agenda to modify the minimum light load and full 

load test procedures for AC and DC systems addressed in paragraph N..32. Accuracy Testing that remain 

under consideration in the 2024 cycle. One reoccurring recommendation that is not part of this proposal

is for a separate new set of test procedures for type evaluation performed under laboratory conditions that 

did not previously exist and would be a substantive change to the 2024 edition of the HB 44. This 

proposal (1) no longer specifies the means used to determine the MDA percentage level achieved during 

accuracy tests, (2) establishes a new MDA range for performing the light load test and the MDA level 

that must be achieved for tests of DC systems when a vehicle is the test load for verifying the EVFS, and 

(3) establishes a new definition of MDA. The proposal continues to recommend removing N.1. No Load 

Test and N.2 Starting Load Test when the August 2023 NCWM took similar action after adopting Agenda 

Item EVF-23.1.

Test procedures are not solely written to the operational characteristics or particular design of one test 

apparatus. Test procedures should encompass operational conditions over the course of the entire 

transactions in the marketplace. Test points should fall within the rated minimum up through the 

maximum operational ranges specified by the manufacturer for the EVFS under normal conditions of 

commercial use. The 2014 USNWG completed its development of the handbook AC and DC systems’ 

light load test and full load test procedures in part because they appeared to be the most likely conditions 

under which equipment would be used during a charging session and based on existing test procedures 

and knowledge about watt-hour type electric meters. Watthour type electric meters were the only 

electrical energy device regulated by U.S. weights and measures in the 2012 timeframe. For each gap in 

the EVSE infrastructure there have been stakeholders indicating a solution is possible. The community 

was advised to wait for completion of performance criteria for DC meters which became available in 

March 2021 in ANSI C 12.32-2021 American National Standard for Electricity Meters for the 

Measurement of DC Energy and would be an important reference document for DC type electricity 

metering in EVFSs. Therefore, with a decade of experience with EVFSs having gone through type 

evaluation (i.e., CADMS) and test equipment designed to verify both AC and DC systems and the 

laboratory community both closing in on filling the last gaps in the EVSE weights and measures 

infrastructure. It becomes important and necessary that all stakeholders (EVSE/test equipment 

manufacturers, type examiners, and regulators) reach a consensus on test procedures. 

The EVFS test standard must be fit for purpose or appropriate and suitable (this might be demonstrated by 

data) in its design, capacity, and accuracy; and would allow for replication of the manner in which the 

EVSE is used in commerce. The test standard used to verify an EVSE must also meet the NIST HB 44 

Appendix A Fundamental Considerations for a test apparatus. 

The term “maximum deliverable amperes” that is abbreviated as “MDA” would be defined as “the 

highest current value or highest level of current or highest total current capacity at which the 

manufacturer has designed the EVFS to operate and meet accuracy.” The current level at the installation 

site and for test equipment shall be suitable for the MDA rating of the EVFS. The term “maximum 

deliverable amperes” is cited in multiple requirements in the EVFS Code and is relevant to test conditions 

and is also required marking information on the EVFS. For clarity the “meaning portion” of a definition 

should not include the term or parts of the term it is defining nor cite one of the many code paragraphs 

where the term is used because the appearance can be the term is unique to that sole paragraph. 

Therefore, the term’s definition should include reference to the EVFS Code numerical section designation 

in brackets (i.e., [3.40]) at the end of the definition rather cite a single applicable code requirement or 

paragraph. The EVFS is a permanent code and definitions applicable to the code should be included in 

Appendix D – Definitions. 
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The proposal appeared to have incorrectly renumbered paragraph N.5. Accuracy Testing to become 

N.5.2.1.. Previous publications of the proposal did not show paragraph N.5.2 in entirety, so there was 

question as to whether the submitter was proposing to remove the 2028 enforcement date? 

The 2023 NCWM requested this proposal along with Item EVF-23.4 which took a different approach to 

updating the test procedures be considered and possibly be consolidated by the USNWG EVFE 

Subgroup. In May 2023 the EVFE Subgroup tasked its Test Procedure Subcommittee (TPS) to undertake 

this project. After input from the submitters of both proposals and other U.S. stakeholders, and multiple 

meeting deliberations (June through December 2023) the TPS arrived at a draft (see the NIST OWM 

analysis section for EVF-23.4) that combines elements of both proposals under EVF-23.4 that it will send 

to the EVFE Subgroup mid-December 2023 for its consideration. The NIST Technical Advisor has noted 

there are five places in the modified test procedures and new definitions needing further refinement to 

ensure uniform interpretation and application of the test procedure requirements. The Submitters agreed 

in late August to combine the desired elements from both proposals under a single agenda item and to 

also recommend withdrawing of EVF-23.7. 

U.S. National Work Group’s Electric Vehicle Fueling Equipment Subgroup (EVFE SG)

Several proposals developed by the EVFE Subgroup membership to modify NIST Handbook 44 Section 

3.40 paragraphs N.5.1. Performance Verification in the Field and N.5.2. Accuracy Testing have been 

under discussion by the EVFE Subgroup since May 2022. The EVFE Subgroup had not reached a 

consensus on a comprehensive set of modifications to the current test procedure requirements in the 2023 

edition of NIST Handbook 44. The handbook N. Notes paragraphs (1) identify the minimum testing that 

applies in the official test of a device and (2) are used by the type evaluation program technical sector or 

work group as the basis for the key parts of the device test criteria checklist these technical committees 

will develop. These proposals to modify EVSE handbook requirements have evolved over the past two 

years as a result of lessons learned about EVSE operations in a variety of installation sites, the increased 

capacity of charging equipment since the codes inception, and the application of code requirements 

during type evaluation and to commercial operations for the past seven years. The EVFE Subgroup has 

also over the past five years reviewed all proposals to modify EVSE handbook requirements appearing on 

the NCWM S&T and L&R Committees Agendas to include 2023 Developing Items EVF-23.4 & EVF23.7. Both agenda items contain proposals to modify paragraphs N.5.1. and N.5.2. The proposals in 

these two agenda items were not developed by the EVFE Subgroup although the submitters of both 

proposals are active members of the Subgroup. 

The EVFE Subgroup’s Test Procedures Subcommittee (TPS) was tasked in May 2023 by the EVFE 

Subgroup to consider a recently modified version of the test procedures addressed in Item EVF 23.4. 

This latest modified version of the test procedures is the result of the collaborative effort of the submitters 

of both proposals. Based on the TPS’s findings the Subgroup has targeted the upcoming 2024 standards 

development cycle to develop and provide input on both Items EVF-23.4 and EVF-23.7. Input received 

June 2023 in the outreach to stakeholders and over the course of TPS deliberations from July through 

November have resulted in further refinement to an August 2023 proposal that is a combination of both 

items. After input from the submitters of both proposals and other U.S. stakeholders, and multiple 

meeting deliberations (June through December 2023) the TPS arrived at a draft (see the NIST OWM 

analysis section for EVF-23.4) that combines elements of both proposals under EVF-23.4 that it will send 

to the EVFE Subgroup mid-December 2023 for its consideration. The NIST Technical Advisor has noted 

there are five places in the modified test procedures and new definitions needing further refinement to 

ensure uniform interpretation and application of the test procedure requirements. The Submitters agreed 

in late August to combine the desired elements from both proposals under a single agenda item and to 

also recommend withdrawing of EVF-23.7. 
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Summary of Discussions and Actions: 

At the 2023 NCWM Interim Meeting, Ed Williams (Ventura County, CA) commented the language needs 

clarification on the maximum deliverable amperes and suggested the current language may be restrictive 

since there is a prescriptive range to test within. Keith Bradley (Electrify America) commented it is 

difficult to test EVSE devices at low current and has the least impact to the commercial transaction. 

Keith Bradley stated it is more appropriate to have a range and recommended striking language in Pub.

15, page S&T-287, lines 6-7. Keith Bradley added this item is needed to address low limit testing. Kevin

Schnepp (State of California, Division of Measurement Standards) agrees with Tina Butcher’s comments 

and recommends the submitter work with the NIST USNWG EVFE Subgroup for item development. 

Tina Butcher (NIST OWM) referred to the written comments submitted by NIST OWM. They added 

there is more work needed to develop this item and referred to WWMA’s recommendation to combine 

this item with EVF-23.4 and to work with NIST USNWG EVFE Subgroup for item development.

The Committee considered the comments heard during open hearings and assigned a Developing status to 

the item. The Committee recommends the submitter work with the NIST USNWG EVFE Subgroup for 

item development.

During the 2023 NCWM Annual Meeting the Committee heard input from Keith Bradley indicating work 

was taking place on updates to the proposal.

Regional Association Reporting:

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting, ScheLeese Goudy (Electrify America) remarked that the low end 

test was meant to be at 10 % but as written would allow anything less than 10 %. Less than 10 % is 

unnecessarily difficult. Little energy will be delivered at these low rates. Greater inaccuracies below 10 

%. Move forward as voting. Note the change on N.5.2.1.(b)(2) to “between 10 % and 20 %”. 

Francesca Wahl (Tesla) recommended this move forward as voting. Loren Minnich (Kansas) stated that 

page 252 Line 10, remove the “of” before the range. Craig VanBuren (Michigan) agreed and remarked 

this is Ready for voting with recommended changes.

The CWMA S&T Committee believes this item is fully developed and recommended Voting status with 

the following changes:

N.1. No Load Test. – A no load test may be conducted on an EVSE measuring system by 

applying rated voltage to the system under test and no load applied.

N.2. Starting Load Test. – A system starting load test may be conducted by applying rated 

voltage and 0.5-ampere load.

N.5.2.1. Accuracy Testing. – The testing methodology compares the total energy delivered in a 

transaction and the total cost charged as displayed/reported by the EVSE with that measured by 

the measurement standard.

(a) For AC systems:
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(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes (expressed as MDA) as determined from the pilot signal for a 

total energy delivered of at least twice the minimum measured quantity (MMQ). If 

the MDA would result in maximum deliverable power of greater than 7.2 kW, then 

the test may be performed at 7.2 kW.

(2) Accuracy test of the EVSE system at a load of not greater than between 10 % and 

20 % of the maximum deliverable amperes (expressed as MDA) as determined 

from the pilot signal for a total energy delivered of at least the minimum measured 

quantity (MMQ).

(b) For DC systems (see note):

(1) Accuracy test of the EVSE system at a load of not less than 85 % of the maximum 

deliverable amperes current (expressed as MDA) as determined from the digital 

communication message from the DC EVSE to the test standard for a total 

energy delivered of at least twice the minimum measured quantity (MMQ).

(2) Accuracy test of the EVSE system at a load of not more than between 10 % and 

20 % and 20 % of the maximum deliverable amperes (expressed as MDA) as 

determined from the digital communication message from the DC EVSE to the 

test standard for a total energy delivered of at least the minimum measured 

quantity (MMQ).

Note: For DC systems it is anticipated that an electric vehicle may be used as the test load.

Under that circumstance, testing at the load presented by the vehicle shall be sufficient provided 

that it is greater than 30% of the maximum deliverable amperes of the EVSE system.

And

Appendix D:

maximum deliverable amperes. - The value in amperes, marked on an EVSE pursuant to 

paragraph S.5.2. EVSE Identification and Marking Requirements, of the maximum current that 

the EVSE can provide.

At the 2023 CWMA Annual Meeting, Scheleese Goudy submitter of this proposal and Item EVF-23.7 are 

working to submit a single joint proposal. A general consensus on concerns has been reached. SG 

meeting will be convened to discuss technical aspects of joint proposal. Monica Martinez (Tesla) reports 

that a draft combination of Items EVF-23.4 and EVF-23.7 still being reviewed for technical accuracy. 

The CWMA S&T Committee believes this item is fully developed and recommends voting status. 

However, the regional recommendation to the NCWM was that the proposal be a Developing Item on the 

NCWM agenda.

At the 2023 CWMA Interim Meeting, the Committee heard comments on this item and item EVF-23.4 

concurrently. Comments made about this item will also be found in the comments section on item 

EVF-23.4.
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Theo Brillhart (Fluke) presented material regarding the merge of EVF-23.4 and EVF-23.7 by the 

submitters as well as the passing of item EVF-23.1 at the 2023 Annual NCWM Meeting. The passing of 

item EVF-23.1 has forced a renumbering of sections within this current proposal. The submitters of 

EVF-23.4 and EVF-23.7 have reflected those changes in their proposal. With these changes (letter 

submitted), the submitter recommends this item as voting. 

ScheLeese Goudy agrees with the proposal because it makes testing easier. Language regarding ‘10 amps 

or above’ fixes the concerns between item EVF-23.4 and item EVF-23.7.

Perry Lawton (TESCO) applauds the work achieved between EVF-23.4 and EVF-23.7. Steve Peter 

(Wisconsin) supported this item.

The Committee recommends this item moving forward as a voting item with the proposed changes by the 

submitter which are attached to the bottom of this report (same proposal referenced in item EVF-23.4). 

[Appendix C] 

Western Weights and Measures Association

During the WWMA 2022 Annual Meeting the following comments were received:

ScheLeese Goudy commented the item is written to allow testing at any current and the rate to charge is 

very low compared to the 10 % accuracy. ScheLeese Goudy commented these tests make inspectors wait 

and are not meaningful for the accuracy of an EV charger. ScheLeese Goudy commented there was a 

broad consensus at the USNWG but no official vote was taken by the Work Group. ScheLeese Goudy

recommended a Voting status.

Chris King commented Siemens targets a 10 % accuracy test. Chris King commented Siemens is in favor 

of the change.

Francesca Wahl seconded the comments by Electrify America and Siemens. Francesca Wahl

recommended a Voting status.

Kevin Schnepp (California Division of Measurement Standards) commented in full support of 

recommendations to strike the no load and starting load tests. Kevin Schnepp commented he doesn’t 

think there is consensus from the Work Group. Kevin Schnepp recommended that this item be discussed 

with the U.S. National Working Group to make sure that it is highly agreed upon. Kevin Schnepp

proposed if two vehicles are charging at once it cuts the 10 % in half. Kevin Schnepp commented in 

favor the range between 10 and 20%. Kevin Schnepp recommended a Developing status.

During open hearings, comments were heard that contents in this item were previously discussed in the 

USNWG, but no official position has been taken by the USNWG. There were also comments during 

open hearing taking the position the item is not fully developed. The WWMA S&T Committee 

recommended the submitters work with the USNWG to develop one proposal by combining language 

from EVF-23.4.

The WWMA S&T Committee recommended that this item be blocked with item EVF-23.4. The WWMA 

S&T Committee recommended the new blocked items be assigned a Developing status.

At the 2023 WWMA Annual Meeting, the Committee heard comments regarding item EVF-23.4 and this 

item. The WWMA S&T Committee received a letter with updated proposed language for this item and 
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EVF-23.4. The letter has been posted to the WWMA website, Events – Meeting Documents – Letter 

From the Submitters EVF-23.4 and EVF-23.7. This letter has also been provided to NCWM S&T 

Committee. Comments were heard supporting the proposed language in the Joint Letter dated August 22, 

2023.

Kevin Schnepp supports this item with an additional proposed revision of changing the Exemption Date 

from 2028 to 2025.

The WWMA 2023 S&T Committee recommends this item be assigned a Withdrawn status in favor of 

item EVF-23.4. Based on comments heard during open hearings from industry and consideration of the 

Letter from the Submitters this committee recommends that EVF-23.4 be updated with the proposed 

language in the letter and EVF-23.7 be Withdrawn.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Hal Prince (Florida) supported this as a Voting Item. ScheLeese

Goudy recommended this item move forward as a Voting Item.

The SWMA S&T Committee recommended this item move forward as a Voting Item.

At the 2023 SWMA Annual Meeting, the Committee recommended incorporating this item into 

EVF-23.4, and withdrawing this item based upon the proposed joint language provided in a letter dated 

August 22, 2023, from William Hardy and Keith Bradley the submitters of these two items.

The Committee recommends this item be Withdrawn.

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting, Keith Bradley (Electrify America) stated that the core problem is 

testing at low currents. Keith Bradley believes that “10 % to 20 %” is better than “up to 10 %” as no 

currently installed charger will be able to do less than 10 %. Currently, the NIST HB doesn’t qualify 

what the test procedure is for testing device using an EV. Juana Williams (NIST OWM) indicated that 

the removal of “no load test” and “starting load test” is consistent with other proposals viewed by the 

EVFE Subgroup. Juana Williams also questioned how an inspector will know they reached 10 % and 85 

% if there is no pilot signal or information coming from digital communications with the system. Juana. 

Williams also noted that a definition being tied to marking requirement is not typically done. Keith 

Bradley explained that an inspector would know max deliverable amps as it should be marked on the 

device, know the current as displayed by the testing apparatus, then compare. Jason Flint (New Jersey) 

recommended that the item be Developing.

After hearing comments from the floor, the Committee believes the item has merit. The Committee is 

recommending a Developing status.

At the 2023 NEWMA Annual Meeting, Alicia Artessa supported the low end test values to ensure 

accuracy. After hearing comments from the floor, the Committee recommended to the body that this item 

maintain a developing status, and the body concurred.

At the 2023 NEWMA Interim Meeting, after hearing comments on EVF-23.4 and upon consensus of the 

body, the Committee recommends this item be Withdrawn.
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GMA – Grain Moisture Meters 5.56 (a)

GMA-19.1 D Table T.2.1. Acceptance and Maintenance Tolerances Air Oven Method 

for All Grains and Oil Seeds.

Source: NTEP Grain Analyzer Sector

Submitter’s Purpose and Justification:

Reduce the tolerances for the air oven reference method.

This item has been assigned to the submitter for further development. For more information or to provide 

comment, please contact:

Karl Cunningham

Illinois Department of Agriculture

217-785-8301, karl.cunningham@illinois.gov

AMS, FGIS request samples and list of grains from states to include in their ongoing calibration program. 

States and other interested parties wanted to verify that corn samples from their state were included in the 

calibration data for NTEP meters because of variations states reported between UGMA meter and other 

meter technologies on corn samples.

During the 2016 Grain Analyzer Sector Meeting, numerous instances of inconsistent moisture meter 

measurements involving grain shipments from U.S. interior facilities to U.S. export port facilities were 

reported. The Sector received a suggestion that if the UGMA can make better measurements, then the 

Sector should consider reducing the applicable tolerances in HB 44. At the 2016 and 2017 Grain 

Analyzer Sector meetings Charlie Hurburgh (Iowa State University) agreed to chair a GA Sector Task 

Group to review the current HB 44 tolerance with both UGMA meters and non-UGMA meters. During 

the 2018 meeting Charlie Hurburgh reported that based on data they analyzed from Iowa State Weights 

and Measures Grain Inspection reports, UGMA meters read closer to the reference air oven moisture 

results than non-UGMA meters.

It was also noted during the 2018 NTEP Grain Analyzer Sector meeting that the current tolerances were 

developed in 1991 and have not been changed to coincide with the change in technology for these 

devices; and this action is needed for grain industry risk management.

Prior to the 2019 NCWM Interim Meeting, all four regional weights and measures associations agreed to 

forward the proposal as a voting item on the Interim Agenda. However, following the regional meetings, 

additional data was submitted to the Sector which indicates a need to consider developing different 

tolerance for some grain types. Through a subsequent ballot, and a majority vote, the Sector agreed to 

recommend changing the status of the item to developing to provide the Sector time to consider additional 

data and changes to its original proposal.
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NIST OWM Executive Summary for GMA-19.1 – Table T.2.1. Acceptance and Maintenance 

Tolerances Air Oven Method for All Grains and Oil Seeds

NIST OWM Recommendation: NIST OWM supports the Grain Analyzer Sector’s decision to 

Withdraw this item recognizing that if additional data is received the proposed tolerance changes may 

be resubmitted for consideration. 

• During the NTEP Grain Analyzer (GA) Sector 2019 meeting, the Sector reviewed data from 

Arkansas for Long Grain Rough Rice (LGRR) and other grains. The data showed that the 

proposal to tighten the acceptance and maintenance tolerance may not be appropriate for all 

grain types. The original data presented and used as a basis for the proposal applied to corn 

and soybeans. After reviewing the data, the Sector decided to collect inspection data from 

across the country. An industry representative offered to assist with data analysis and along 

with the NIST representative will work in producing the inspection data needed for the 

analysis. A request for State participation will be sent to State weight and measures. The 

Sector requests that this remain a Developing Item as they move forward in evaluating 

additional data.

• North Carolina submitted the requested grain data for review. Field meter inspection data from 

the state of North Carolina for years 2017 to 2019 was examined and comprised over 3300 

records each usually averaged 3 commodity drops on UGMA and Non-UGMA meter types.

While only one state’s data cannot be considered representative of all the other states, the 

results provide indications of trouble with decreased tolerances on both UGMA and NonUGMA meter types.

• The Grain Analyzer Sector has not received additional data needed to further assess their 

proposed tolerances changes to NIST HB 44, Section 5.56(b) The GA Sector will keep this as 

an open item on their Sector agenda, but as the submitter of this item, the GA Sector 

recommends that this item be withdrawn. If or when additional data is received, the Grain 

Analyzer Sector may resubmit the item.

Table 2. Summary of Recommendations

GMA-19.1 – Table T.2.1. Acceptance and Maintenance Tolerances Air Oven Method for All Grains 

and Oil Seeds

Status Recommendation Note* Comments

Submitter Withdrawn

OWM Withdrawn

WWMA Developing

NEWMA Withdrawn

SWMA Withdrawn

CWMA Developing

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments
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Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Grain Moister Meter Code 5.56 (a) as follows:

T.2.1. Air Oven Reference Method. – Maintenance and acceptance tolerances shall be as shown in 

Table T.2.1. Acceptance and Maintenance Tolerances Air Oven Reference Method. Tolerances are 

expressed as a fraction of the percent moisture content of the official grain sample, together with a 

minimum tolerance.

(Amended 2001)

Table T.2.1. Acceptance and Maintenance Tolerances Air Oven Reference Method

Type of Grain, Class, or Seed Tolerance Minimum Tolerance

Corn, oats, rice, sorghum, 

sunflower

0.05 of the percent

moisture content

0.8 %

in moisture content

All other cereal grains and oil 

seeds

0.04 of the percent

moisture content

0.7 %

in moisture content

Table T.2.1. Acceptance and Maintenance Tolerances Air Oven Reference Method for All Grains 

and Oil Seeds

Tolerance Minimum Tolerance

0.03 of the percent moisture content 0.5 % in moisture content

(Amended 2001 and 20XX)

NIST OWM Detailed Technical Analysis: 

During the NTEP Grain Analyzer (GA) Sector 2019 meeting, the Sector reviewed data from Arkansas for 

Long Grain Rough Rice (LGRR) and other grains. The data showed that the proposal to tighten the 

acceptance and maintenance tolerance may not be appropriate for all grain types. The original data 

presented and used as a basis for the proposal applied to corn and soybeans. After reviewing the data, the 

Sector decided to collect inspection data from across the country. An industry representative offered to 

assist with data analysis and along with the NIST representative will work in producing the inspection 

data needed for the analysis. A request for State participation will be sent to State weight and measures. 
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The Sector requests that this remain a Developing Item as they move forward in evaluating additional 

data. 

At the 2020 Interim Meeting the S&T Committee agreed to retain this item as Developing in anticipation 

of additional data that is being collected to assess the proposed tolerances and the appropriateness of the 

change to tolerances for other grain types. The NIST Technical Advisor is working with the Grain 

Analyzer Sector and States to collect additional data on the proposed changes to the tolerances with plans 

to present data at the next NTEP GA Sector Meeting in August 2021. NIST OWM agrees with the S&T 

Committee that this item should be given a Developing status until additional data is examined.

Diane Lee (NIST) is working with the Sector to collect data on Unified Grain Moisture Algorithm 

(UGMA) grain moisture meters and non-UGMA grain moisture meters. North Carolina, Arizona, 

Illinois, and Iowa agreed to provide 2017-2019 inspection data on field meters. The participating States 

were requested to submit data by December 1, 2021. One state will be unable to participate, and North 

Carolina has submitted their data.

During the 2022 Grain Analyzer Sector Meeting the Sector reviewed data from North Carolina. 

Regarding potential changes to “Handbook 44” tolerances for Grain Moisture Meters, field meter 

inspection data from the state of North Carolina for years 2017 to 2019 was examined. Only the one state 

provided data, but that comprised over 3300 records each usually averaging 3 commodity drops on 

UGMA and Non-UGMA meter types. While only one state’s data cannot be considered representative of 

all the other states, the results here provide indications of trouble with decreased tolerances on both 

UGMA and Non-UGMA meter types. The following provide a percentage of device that exceeded the 

current tolerance compared to the percentage of meters that would exceed the proposed tolerance.

The Sector has requested additional data from other States to gain a better perspective on the impact of 

lowering the tolerances for grain moisture meters. 

At the 2023 Grain Analyzer Sector meeting, Sector members noted that no additional data had been 

received. As such the GA sector recommended that the item be withdrawn. The Sector will keep this 

item on their agenda and resubmit the proposal to the S&T if or when additional data is submitted that can 

be used to support the recommended tolerance changes. 

History

The GA Sector originally forwarded this proposal to the regional weights and measures associations with 

a proposed Voting status. All regional weights and measures associations agreed to forward the proposal 

as a voting item on the 2019 NCWM Interim Agenda and the Sector appreciates their review and support. 

However, following the regional meetings additional data was submitted to the sector which indicates a 

need to consider developing different tolerance for some grain types. Through a subsequent ballot, and a 

majority vote, the sector agreed to recommend changing the status of the item to developing to provide 

the Sector time to consider additional data and changes to its original proposal. OWM agrees with the 

Grain Analyzer (GA) Sector’s revised decision to change the status of this item to Developing.

Exceed current 

tolerance (UGMA)

Exceed current 

tolerance (NonUGMA)

Exceed proposed 

tolerance (UGMA)

Exceed proposed 

tolerance (NonUGMA)

Count 10 18 54 263

Records 1146 2208 1146 2208

Fraction 0.87% 0.82% 4.71 % 11.91 %
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This proposal to change the air-oven method tolerances was developed during the 2018 GA Sector 

meeting. During the 2018 GA Sector Meeting, Charlie Hurburgh provided the Sector with an analysis of 

data for 2-corn and 1-soybeans samples which included the average error for UGMA grain moisture 

meter technology and the average error of 2 MHz grain moisture meter technology from Iowa State 

weights and measures inspection data for years 2014-2017. Based on the Sectors review of the data, 

discussion of new tolerances, and the ability of the technologies to meet the new tolerances the Sector 

agreed to change the tolerances based on the data provided.

During additional discussion of what tolerances to apply to other grains, it was proposed that the same 

tolerances could apply to all grains, because corn is one of the more difficult grains to test and would 

likely have one of the largest variations when testing. No objections from States or meter manufacturers 

were provided during the discussion and voting to forward the item to the State regional weights and 

measures associations. Following the Sector meeting one State noted that there may be an issue with 

applying the tolerance to some grain types, specifically long grain rough rice. The GA Sector’s technical 

advisor requested that the State forward field data to review the grain moisture meter results for LGRR 

and other grains. After review of the data with the proposed tolerances it was determined that a high 

meter failure rate could result with a change to the tolerances for some grain types.

After the Sector’s Technical Advisor discussed the findings with the NTEP laboratory and the Sector 

members that originally proposed the tolerance change, they agreed with proposing a Developing status 

for this item, the Sector was officially balloted and also agreed to change the originally proposed Voting 

status to Developing to allow the Sector time to review additional data and make changes to its original 

proposal.

Summary of Discussions and Actions:

At the NCWM 2022 Interim Meeting, the Committee heard comments from Diane Lee (NIST OWM) 

who noted that additional data is needed to assess the proposed tolerances. Diane Lee added that states 

would be submitting more data. Diane Lee requested that this item remain Developing. During the 

Committee’s work session, the Committee agreed to a Developing status for this item.

At the NCWM 2022 Annual Meeting open hearings Tina Butcher (NIST OWM) provided updates on the 

Grain Analyzer Sector’s proposal to reduce the tolerance for grain moisture meters. She informed the 

S&T Committee that the Grain Analyzer Sector had originally reviewed data for corn and soybeans. 

After the proposal for changes to the tolerances were submitted to the NCWM, information was received 

that reducing the tolerance may be problematic for other grains. As such the Grain Analyzer Sector is 

collecting additional data on other grain types and request a Developing status and additional time to 

collect the data.

At the 2022 NCWM Annual Meeting Committee meeting, the Committee agreed to a Developing status 

for this item. 

At the 2023 NCWM Interim Meeting, the S&T Committee heard comments from the floor during open 

hearings. Tina Butcher (NIST OWM) commented that COVID has put a hamper on the collection of data 

that is needed for the study and requested the item remain Developing. The Committee left the item 

Developing.
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Regional Association Reporting:

Western Weights and Measures Association

During the WWMA 2022 Annual Meeting no comments were heard on this item. No additional data or 

update was received by the Committee. The WWMA S&T Committee recommended withdrawal and 

encouraged the submitter to reintroduce the item when sufficient data is available. 

At the 2023 WWMA Annual Meeting, no comments were received from the body on this item.

The WWMA 2023 S&T Committee recommends this item remain a Developing status based on 

comments heard and included in the 2023 NCWM S&T Committee Annual Report; those comments 

indicate data is being collected and reviewed.

Southern Weights and Measures Association

During the 2022 SWMA Annual Meeting open hearing the Committee heard no comments. 

At the 2023 SWMA Annual Meeting, Jason Glass (Kentucky) recommended withdrawing the item due to 

lack of feedback from the submitter.

Aaron Webb (Maryland) stated that the current tolerances were already difficult to achieve and would not 

support changing them.

The Committee recommends Withdrawal of this item, due to no comments in support, feedback, or 

development of this item over several years.

Northeastern Weights and Measures Association

During the 2022 NEWMA Interim Meeting, Diane Lee indicated the need for more data on more grains. 

This proposal is seeking to lower tolerances due to better technologies of UGMA meters. However, 

according to data submitted by North Carolina, grains are failing at the proposed tolerances. Diane Lee 

requests more time so more states can submit data. 

The Committee is recommending that this item retain a Developing status. 

During the 2023 NEWMA Annual Meeting, the Committee heard no comments on this item but 

recommended to the body that this item retain a developing status. The body concurred.

At the 2023 NEWMA Interim Meeting, a regulator from the Pennsylvania commented that the Task 

Group was still waiting for additional data to move forward with this item. A regulator from Holliston, 

Massachusetts recommended this item be withdrawn as it has been on the agenda for four years without 

data collection being completed, and once it has been collected and analyzed, it can be reintroduced. New 

Hampshire, Vermont, Connecticut, Pennsylvania, and Massachusetts concur. Upon consensus of the 

body, the Committee recommends this item be Withdrawn.

Central Weights and Measures Association 

During the 2022 CWMA Interim Meeting Open Hearings, Doug Musick (Kansas) recommended that 

item remain developing, while waiting on additional data. Ivan Hankins (Iowa) stated that 0.5% tolerance 

is fair and should move forward to Voting.
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The CWMA S&T Committee recommended this remains a Developing Item to allow time to collect 

additional data.

During the 2023 CWMA Annual Meeting, Loren Minnich (NIST OWM) noted the Grain Analyzer Sector 

is still waiting on data for certain types of grain to verify tolerances are achievable and that NIST supports 

a Developing status.

The CWMA S&T Committee recommends this item remain Developing. 

OTH – Other Items

OTH-16.1 I Electric Watthour Meters Code under Development

Source: NIST Office of Weights and Measures

Submitter’s Purpose and Justification:

1. Make the weights and measures community aware of work being done within the NIST U.S. 

National Work Group (USNWG) on Electric Vehicle Fueling and Submetering in the USNWG’s 

Watthour Type Electric Meters (WHE) Subgroup (SG) to develop proposed requirements for 

electric watthour meters used in submeter applications in residences and businesses;

2. Encourage participation in this work by interested regulatory officials, manufacturers, and users 

of electric submeters.

3. Allow an opportunity for the USNWG to provide regular updates to the S&T Committee and the 

weights and measures community on the progress of this work;

4. Allow the USWNG to vet specific proposals as input is needed.

Those interested in participating in this work please contact:

Subgroup Chair, Lisa Warfield (NIST OWM)

Email (lisa.warfield@nist.gov) or phone (301) 975-3308

Subgroup Technical Advisor, Juana Williams (NIST OWM)

Email (juana.williams@nist.gov) or phone (301) 975-3989

NIST OWM Executive Summary for OTH-16.1 – Electric Watthour Meters Code Under 

Development

NIST OWM Recommendation: Informational with an upgrade in status should the stakeholders 

reach agreement by March 2024.

• The title of this Item should read “Non-Utility Electricity-Measuring Systems (NUEMS) –

Tentative Code”.
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NIST OWM Executive Summary for OTH-16.1 – Electric Watthour Meters Code Under 

Development

• Most members supported the proposed language as it currently appeared in the 2023 S&T 

Agenda (NCWM Pub. 16), although regulatory members of the SG disagreed with the 

proposed language. 

• In addition, the regulatory members provided a detailed list to the WHE SG of their concerns. 

These concerns are noted in the letter that NCWM received from the California Agricultural 

Commissioners and Sealers Association (CACASA) (dtd. June 29, 2023) and posted under the 

NCWM S&T Supporting document website.

• The WHE SG attempted to address the regulators and CACASA concerns. They made 

headway in addressing those concerns and they appear in the Crosswalk below. 

• The Crosswalk below, provides updates of items that appear in the 2023 S&T Annual Agenda 

(Pub. 16). They represent changes the WHE SG voted on to move forward to the S&T 

Committee for consideration. Due to limited time, the WHE SG was not able to address all the 

items, and the work continues.

Crosswalk

Watthour Type Electric Submeters submitted recommendations to S&T Agenda Item OTH-16.1. 

Electric Watthour Meters Tentative Code

Paragraph as it appears on S&T 2023 Annual 

Agenda (Pub. 16):

Changes represented in bold strikethrough or 

underscore and followed by a clean version

A.4. Type Evaluation. – The National Type 

Evaluation Program (NTEP) will accept for type 

evaluation only those measuring systems that have 

received safety certification by a nationally recognized 

testing laboratory (NRTL) and shall issue an NTEP 

Certificate of Conformance only to those measuring 

systems that comply with all requirements of this code.

A.4. Type Evaluation. – The National Type 

Evaluation Program (NTEP) will accept for type 

evaluation only those measuring systems that have 

received safety certification by a nationally recognized 

testing laboratory (also referred to as “NRTL”) and 

shall issue an NTEP Certificate of Conformance only to 

those measuring systems that comply with all 

requirements of this code.

Clean version:

A.4. Type Evaluation. – The National Type 

Evaluation Program (NTEP) will accept for type 

evaluation only those measuring systems that have 

received safety certification by a nationally recognized 

testing laboratory (also referred to as “NRTL”) and shall 

issue an NTEP Certificate of Conformance only to those 

measuring systems that comply with all requirements of 

this code.

S.1.3.2. Test Output. – Each NUEMS within a 

system shall have either: (1) a location for the reading of 

the accumulated value; (2) a pulse output (visible and/or 

infrared pulse), an electrical pulse output in the form of 

a closure (relay or electronic such as an open drain field 

S.1.3.2. Test Output. – Each A NUEMS within a 

system shall have either: (1) a location for the reading 

of the accumulated valuea rotating disk indicator; 

(2) an electrical pulse output (visible and/or infrared 

pulse), or (3) an electrical pulse output (in the form of 
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Crosswalk

Watthour Type Electric Submeters submitted recommendations to S&T Agenda Item OTH-16.1. 

Electric Watthour Meters Tentative Code

Paragraph as it appears on S&T 2023 Annual 

Agenda (Pub. 16):

Changes represented in bold strikethrough or 

underscore and followed by a clean version

effect transistor (FET)) which provides a pulse at an 

interval of Kt Watt-Hours per pulse; or (3) other means 

for viewing accumulated values. The value of Kt shall 

be such that the NUEMS’s accuracy can be tested in 5 

minutes or less for any specified test condition.

a closure (relay or electronic means), which provides a 

pulse at an interval of with Kt or KhWatt-Hours per 

pulse; or (3) other means for viewing accumulated 

values. The value of Kt or Kh shall be such that the 

NUEMS’s accuracy can be tested in 5 minutes or less 

for any specified specific test condition.

Clean version: 

S.1.3.2. Test Output. – A NUEMS shall have either: 

(1) a rotating disk indicator; (2) a pulse output (visible 

or infrared), or (3) an electrical pulse (in the form of a 

closure relay or an electronic means), which provides a 

pulse with Kt or Kh Watt-Hours per pulse. The value of 

Kt or Kh shall be such that the NUEMS’s accuracy can 

be tested in 5 minutes or less for any specific test.

S.1.3.6. NUEMS With External Sensors Located 

Remotely from the Pulse Output or Display. – For 

NUEMS with external sensors located remotely from 

either the pulse output or display which can be installed 

as described in paragraph UR.2.4.8. External Sensors 

Located Remotely from the Pulse Output or Display, 

means shall be provided to allow either the pulse output 

or display to be remotely used.

S.1.3.6. NUEMS With External Sensors Located 

Remotely from the Pulse Test Output or Display. –

For NUEMS with external sensors located remotely 

from either the pulse test output or display which can 

be installed as described in paragraph UR.2.4.8. 

External Sensors Located Remotely from the Pulse

Test Output or Display, means shall be provided to 

allow either the pulse test output or display to be 

remotely used.

Clean Version

S.1.3.6. NUEMS With External Sensors Located 

Remotely from the Test Output. – For NUEMS with 

external sensors located remotely from the test output 

which can be installed as described in paragraph 

UR.2.4.8. External Sensors Located Remotely from the 

Test Output, means shall be provided to allow the test 

output to be remotely used.

Add into Table S.3.2.3.a. Device Identification and Marking Requirements for External Sensor (ES) 

NUEMS

Physical Marking Electronic

Sensor True Ratio (12) Nonretroactive as of January 1, 

2024. O D

Kh or Kt (1213) O D
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Crosswalk

Watthour Type Electric Submeters submitted recommendations to S&T Agenda Item OTH-16.1. 

Electric Watthour Meters Tentative Code

Paragraph as it appears on S&T 2023 Annual 

Agenda (Pub. 16):

Changes represented in bold strikethrough or 

underscore and followed by a clean version

Bi-directional (1314) O D

Temperature Range if narrower than −20 °C to + 50 °C 

(− 4 °F to + 122 °F) (1415) O D

Add into Table S.3.2.3.b. Descriptors for Device Identification and Markings Requirement of External 

Sensor (ES) NUEMS

12. True Ratio.

True Ratio. The True Ratio, in primary amperes or volts to secondary amperes or volts shall be 

physically marked on a meter unless it is contained in either electronic or printed documentation. This 

is to be expressed as xxxA:yyyA; or xxxA:yyyV; or xxxV:yyyV. The number of digits is the number 

needed to express the values.

Examples of sensor ratio markings include:

200A:5A

400A:0.3V

480V:120V

T.2. No-Load Test. – For NUEMS with a Kt/Kh

output, the NUEMS shall not emit more than one Kt/Kh

pulse. For NUEMS without a pulse output, the register 

indication shall not change by more than 0.05 % of the 

energy at Current Class (CL) or the Sensor Primary 

Current Rating at unity power factor and rated voltage. 

Also see Note N.1. NUEMS No-Load Test.

T.2. No-Load Test. – For A NUEMS with a Kt/Kh

output, the NUEMS shall not emit more than one 

Kt/Kh test pulse output. For NUEMS without a pulse 

output, the register indication shall not change by 

more than 0.05 % of the energy at Current Class 

(CL) or the Sensor Primary Current Rating at unity 

power factor and rated voltage. Also see Note N.1. 

NUEMS No-Load Test.

Clean Version

T.2. No-Load Test. – A NUEMS shall not emit more 

than one test pulse output. 

N.3. Minimum Test Duration. – Full and light load 

tests shall require at least a one-minute test and at least 

one watthour test constant.

N.3. NUEMS Minimum Test Duration. – A 

NUEMS fFull load test shall consist of a minimum of 

10 watthour test constants and a light load tests shall 

require at least a one-minute test and at least consist 

of a minimum of one watthour test constant.

Clean Version

N.3. NUEMS Minimum Test Duration. – A 

NUEMS full load test shall consist of a minimum of 10 
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Crosswalk

Watthour Type Electric Submeters submitted recommendations to S&T Agenda Item OTH-16.1. 

Electric Watthour Meters Tentative Code

Paragraph as it appears on S&T 2023 Annual 

Agenda (Pub. 16):

Changes represented in bold strikethrough or 

underscore and followed by a clean version

watthour test constants and a light load test shall consist 

of a minimum of one watthour test constant.

S.3.3. Device Identification and Marking 

Requirements – External Sensors. – In addition to all 

the marking requirements of Section 1.10 General Code, 

paragraph G-S.1. Identification, each external sensor 

that is non-integral with the meter shall have the 

following conspicuously, legibly, and indelibly marked 

on a permanent identification label as shown in Table 

S.3.3.a. Device Identification and Marking 

Requirements - External Sensors and in Table S.3.3.b. 

Descriptors for Table S.3.3.a. Device Identification and 

Marking Requirements - External Sensors.

S.3.3. Device Identification and Marking 

Requirements – External Sensors. – In addition to all 

the marking requirements of Section 1.10 General Code, 

paragraph G-S.1. Identification, each external sensor 

that is non-integral with the meter shall have the 

following conspicuously, legibly, and indelibly marked 

on a permanent identification label as shown in Table 

S.3.3.a. Device Identification and Marking 

Requirements – External Sensors and in Table S.3.3.b. 

Descriptors for Table S.3.3.a. Device Identification and 

Marking Requirements – External Sensors.

Clean Version

S.3.3. Device Identification and Marking 

Requirements – External Sensors. – In addition to all 

the marking requirements of Section 1.10 General Code, 

paragraph G-S.1. Identification, each external sensor 

that is non-integral with the meter shall have the 

following conspicuously, legibly, and indelibly marked 

as shown in Table S.3.3.a. Device Identification and 

Marking Requirements – External Sensors and in Table 

S.3.3.b. Descriptors for Table S.3.3.a. Device 

Identification and Marking Requirements – External 

Sensors.

Appendix D. Definitions

bidirectional. – A NUEMS equipped to register the 

accumulation of energy in both directions (i.e., for 

delivered and received energy):

A bidirectional NUEMS shall fall into at least one of 

the following categories: 

(a) Single register or net meter that displays the 

difference between the delivered and 

received energy; or

(b) Separate register(s) for delivered or 

received energy. [3.XX]
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Crosswalk

Watthour Type Electric Submeters submitted recommendations to S&T Agenda Item OTH-16.1. 

Electric Watthour Meters Tentative Code

Paragraph as it appears on S&T 2023 Annual 

Agenda (Pub. 16):

Changes represented in bold strikethrough or 

underscore and followed by a clean version

external sensor. – Any voltage sensor or current 

sensor not located inside of the meter body NUEMS 

itself and not inside the sealed enclosure containing 

the NUEMS. [3.XX]

internal sensor. – Any voltage sensor or current 

sensor located inside of the meter body NUEMS 

itself or inside the sealed enclosure containing the 

NUEMS. [3.XX]

non-integral. – Used to describe external sensors 

that can be disconnected from the meter body. 

[3.XX]

Table 2. Summary of Recommendations

OTH-16.1 – Electric Watthour Meters Code Under Development

Status Recommendation Note* Comments

Submitter

OWM Informational Status upgrade if stakeholders have reached 

agreement

WWMA Informational

NEWMA 5 No recommendation

SWMA Informational

CWMA Informational

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda
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5 No recommendation or not considered

Item Under Consideration: 

Add Non-Utility Electricity-Measuring Systems Code to Handbook 44, as follows:

NIST Handbook 44 Device Code Requirements for

Non-Utility Electricity-Measuring Systems

Table of Contents

SECTION 3.XX. - NON-UTILITY ELECTRICITY-MEASURING SYSTEMS – TENTATIVE CODE......222

A. Application ....................................................................................................................................223

A.1. General...................................................................................................................................................223

A.2. Exceptions..............................................................................................................................................223

A.3. Additional Code Requirements..............................................................................................................223

A.4. Type Evaluation.....................................................................................................................................223

A.5. NUEMS Type Notation. ........................................................................................................................223

S. Specifications ....................................................................................................................................223

S.1. Indicating and Recording Elements........................................................................................................223

S.2. Design of Measuring Elements and Measuring Systems........................................................................225

S.3. Markings.................................................................................................................................................226

N. Notes ....................................................................................................................................232

N.1. NUEMS No-Load Test. .........................................................................................................................232

N.2. NUEMS Starting Load Test...................................................................................................................232

N.3. Minimum Test Duration. .......................................................................................................................232

N.4. NUEMS Test Loads...............................................................................................................................232

N.5. Test of a NUEMS...................................................................................................................................232

N.6. Repeatability Tests.................................................................................................................................233

T. Tolerances ....................................................................................................................................233

T.1. Tolerances, General................................................................................................................................233

T.2. No-Load Test..........................................................................................................................................233

T.3. NUEMS Starting Load Test. ..................................................................................................................233

T.4. Load Test Tolerances. ............................................................................................................................233

T.5. Repeatability...........................................................................................................................................234

Ur. User Requirements ....................................................................................................................................234

UR.1. Selection Requirements.......................................................................................................................234

UR.2. Installation Requirements....................................................................................................................234

UR.3. Use of Device......................................................................................................................................236

Appendix D. Definitions ...................................................................................................................................236

SECTION 3.XX. - NON-UTILITY ELECTRICITY-MEASURING SYSTEMS –

TENTATIVE CODE

This tentative code has only a trial or experimental status and is not intended to be enforced. The 

requirements are designed for study prior to the development and adoption of a final code. Officials 
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wanting to conduct an official examination of a Non-Utility Electricity-Measuring System (NUEMS) 

are advised to see paragraph G-A.3. Special and Unclassified Equipment. 

(Tentative Code Added 20XX)

NUEMS Acronym and Definition: As used throughout this code, a Non-Utility ElectricityMeasuring System or “NUEMS” is defined as an electricity measuring system comprised of all the 

metrologically relevant components required to measure electrical energy, store the result, and 

report the result used in non-utility sales of electricity wherein the sale is based in whole or in part 

on one or more measured quantities.

Safety Note: This code does not specifically discuss Safety. It is essential that all personnel working 

with the devices covered by this code and associated electrical equipment be properly trained and

adhere to all applicable safety standards, regulations, and codes. See also General Code Paragraph 

G-N.1. Conflict of Laws and Regulations.

A. Application

A.1. General. – This code applies to measuring systems used in non-utility sales of electric energy 

wherein the sale is based in whole or in part on one or more measured quantities.

A.2. Exceptions. – This code does not apply to:

(a) The use of any measuring system owned, maintained, and/or used by a utility.

(b) Measuring systems used solely for delivering electric energy in connection with operations 

in which the amount delivered does not affect customer charges or compensation.

(c) Electric vehicle fueling systems. (See 3.40. Electric Vehicle Fueling Systems Code)

(d) Transactions not subject to weights and measures authority.

A.3. Additional Code Requirements. – In addition to the requirements of this code, Non-Utility 

Electricity-Measuring Systems shall meet the requirements of Section 1.10. General Code.

A.4. Type Evaluation. – The National Type Evaluation Program (NTEP) will accept for type 

evaluation only those measuring systems that have received safety certification by a nationally 

recognized testing laboratory (NRTL) and shall issue an NTEP Certificate of Conformance only to 

those measuring systems that comply with all requirements of this code.

A.5. NUEMS Type Notation. – Code sections and subsections with an [ES] notation apply to 

External Sensor NUEMS only. Code sections and subsections with a [IS] notation apply to Internal 

Sensor NUEMS only. Code sections and subsections without [ES] or [IS] notation apply to both 

NUEMS types.

S. Specifications

S.1. Indicating and Recording Elements.

S.1.1. Units. – Units for any indicated or recorded measurements shall be as follows:
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Active Energy:kilowatt-hours (kWh)

S.1.1.1. Numerical Value of Quantity-Value Divisions. – The value of an increment shall be 

equal to a decimal multiple or submultiple of 1.

Examples: quantity-value divisions may be 10; or 0.01; or 0.1; etc.

S.1.1.2. Digital Indications. – An indication shall include the display of a number for all 

places that are displayed to the right of the decimal point and at least one place to the left. 

Otherwise, leading zeros are not required.

S.1.2. Nominal Capacity. – A device shall have a minimum capacity indication of five digits of 

resolution.

[Nonretroactive as of January 1, 20XX]

S.1.3. NUEMS Indications.

S.1.3.1. Primary Indicating Element. – Each NUEMS shall be equipped with a primary 

indicating element that includes a display visible and accessible after installation which 

clearly indicates the number of kilowatt-hours measured by the NUEMS.

S.1.3.2. Test Output. – Each NUEMS within a system shall have either: (1) a location for 

the reading of the accumulated value; (2) a pulse output (visible and/or infrared pulse), an 

electrical pulse output in the form of a closure (relay or electronic such as an open drain 

field effect transistor (FET)) which provides a pulse at an interval of Kt Watt-Hours per 

pulse; or (3) other means for viewing accumulated values. The value of Kt shall be such that 

the NUEMS’s accuracy can be tested in 5 minutes or less for any specified test condition.

S.1.3.3. Segments. – A segmented digital indicating element shall have an easily accessible 

provision for checking that all segments are operational.

S.1.3.4. Real-time Indicating Element. – If the indicating element is not on continuously, it 

shall be accumulated continuously so that real-time measurement is indicated during 

activation.

S.1.3.5. Multiple NUEMS, Single Indicating Element. – A primary indicating, or 

combination indicating-recording element coupled to two or more NUEMS shall be 

provided with a means to easily, clearly, and definitely display information from a selected 

NUEMS and shall automatically indicate which NUEMS is associated with the currently 

displayed information.

S.1.3.6. NEUMS With External Sensors Located Remotely from the Pulse Output or 

Display. – For NUEMS with external sensors located remotely from either the pulse output 

or display which can be installed as described in paragraph UR.2.4.8. External Sensors 

Located Remotely from the Pulse Output or Display, means shall be provided to allow 

either the pulse output or display to be remotely used.

S.1.3.7. NUEMS With a Register Ratio. For NUEMS with a register ratio, the register 

ratio shall be indicated on the front of the registers that are not an integral part of the 

NUEMS nameplate. Means shall be provided for the tenant to read the register.
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S.2. Design of Measuring Elements and Measuring Systems.

S.2.1. Metrological Components. – A NUEMS shall be designed and constructed so that 

metrological components are adequately protected from environmental conditions likely to be 

detrimental to accuracy based on the specified installation locations for the NUEMS.

S.2.2. Provision for Sealing. – Adequate provision shall be made for an approved means of 

security (e.g., data change audit trail) or physically applying security seals in such a manner 

that undetected access to metrologically significant mechanisms and parameters is prevented. 

Specifically, after sealing no adjustment or change may be made to:

(a) any measuring element;

(b) any metrological parameter that affects the metrological integrity of the device or 

system; and

(c) any wiring connection which affects the measurement.

When applicable, any adjusting mechanism shall be readily accessible for purposes of affixing a 

security seal. Audit trails shall use the format set forth in Table S.2.3. Categories of Device and 

Methods of Sealing.

Table S.2.3.

Categories of Device and Methods of Sealing

Categories of Device Method of Sealing

Category 1: No remote configuration capability. Seal by physical seal or two event counters: one for 

calibration parameters and one for configuration 

parameters.

Category 2: Remote configuration capability, but 

access is controlled by physical hardware. 

The device shall clearly indicate that it is in the 

remote configuration mode and record such 

message if capable of printing in this mode or shall 

not operate while in this mode.

(1) The hardware enabling access for remote 

communication must be on-site. The hardware 

must be sealed using a physical seal or an event 

counter for calibration parameters and an event 

counter for configuration parameters. The event 

counters may be located either at the individual 

measuring device or at the system controller; 

however, an adequate number of counters must be 

provided to monitor the calibration and 

configuration parameters of the individual devices 

at a location. If the counters are located in the 

system controller rather than at the individual 

device, means must be provided to generate a hard 

copy of the information.
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Category 3: Remote configuration capability 

access may be unlimited or controlled through a 

software switch (e.g., password).

The device shall clearly indicate that it is in the 

remote configuration mode and record such 

message or shall not accumulate kWh while in this 

mode.

An event logger is required in the device; it must 

include an event counter (000 to 999), the 

parameter ID, the date and time of the change, and 

the new value of the parameter. A printed copy of 

the information must be available through the 

device or through another on-site device. The event 

logger shall have a capacity to retain records equal 

to 10 times the number of sealable parameters in 

the device, but not more than 1000 records are 

required. (Note: Does not require 1000 changes to 

be stored for each parameter.)

S.2.4. NUEMS Watthour Registration Retention. – The NUEMS shall retain the total 

accumulated watthour registration and shall not be affected by electrical, mechanical or 

temperature variations, radio-frequency interference, power failure, or any other 

environmental influences to the extent that accuracy is impaired. This also applies to other 

billable quantities.

S.3. Markings. – The following identification and marking requirements are in addition to the 

requirements of Section 1.10 General Code, paragraph G-S.1. Identification.

S.3.1. Location of Marking Information. – The marking information may be placed either 

internally or externally (as specified in paragraphs S.3.2. Device Identification and Marking 

Requirements and S.3.3. External Sensor Identification and in the associated tables) provided:

i. the information is permanent and easily read; and accessible for inspection; 

ii. the information is on a portion of the device that cannot be readily removed or 

interchanged (e.g., not on a service access panel). A readily removable cover is an 

acceptable location for the required information provided: (1) the information is 

permanently marked elsewhere on the device or is readily accessible through other means 

such as through an electronic display; or (2) a unique marking on the removable cover 

can be matched with what is programmed into or permanently marked on the meter, thus 

linking that marking (and any other markings) included on the cover with that specific 

device.

iii. accessing the information does not require accessing an area with live exposed voltages 

greater than 40 V.

The use of a key or tool to access internal marking information is permitted for retail 

electricity-measuring devices. Where possible, clear covers should be used to enable viewing of 

internally marked information.

S.3.2. Device Identification and Marking Requirements. – In addition to all the marking 

requirements of Section 1.10 General Code, paragraph G-S.1. Identification, each device shall 

have the following information conspicuously, legibly, and indelibly marked on the nameplate 

or register.
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S.3.2.1. Device Identification and Marking Requirements of Meter with External Sensors 

– Sensor input connection with intended polarity shall be physically marked on the meter 

when direction-sensitive.

S.3.2.2. Device Identification and Marking Requirements, Internal Sensor (IS) NUEMS. –

The following markings shall be physically marked on an Internal Sensor (IS) NUEMS:

(f) AC voltage range or rating in VAC;

(g) Watthour test constant (Kh) or Watthour test constant(Kt);

(h) Register ratio (Rr or Kr) for meters with a rotating disc and multiplier (if greater 

than one) preceded by “multiply by” or “mult by” or “Kr”;

(i) Number of wires (W);

(j) Form designation (FM) (for A-base and socket NUEMS only); and

(k) Current Class (CL).

S.3.2.3. Device Identification and Marking Requirements of Meters, External Sensor (ES) 

NUEMS. –In addition to all the marking requirements of Section 1.10 General Code, 

paragraph G-S.1. Identification, External Sensor (ES) NUEMS shall have the following 

legibly, and indelibly marked on the meter as shown in:

• Tables S.3.2.3.a. Device Identification and Marking Requirements of Meter –

External Sensor (ES) NUEMS; and

• Table S.3.2.3.b. Descriptors for Table S.3.2.3.a. Device Identification and Marking 

Requirements of Meter – External Sensor (ES) NUEMS.

(a) service type or service configuration.

Table S.3.2.3.a.

Device Identification and Marking Requirements for External Sensor (ES) NUEMS

Physical Marking Electronic

Display*, **

Manufacturer or Distributor name, initials, or 

trademark (1) R D

Model Prefix (2) O D

Model (3) R D

Serial Number Prefix (4) O D

Serial Number (5) R D

NTEP CC Number with Prefix (6) R D

NUEMS Voltage Input Rating (7) Nonretroactive as of 

January 1, 2024. O D
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Voltage Sensor Rating (8) Nonretroactive as of January 1, 

2024. O D

Voltage Sensor Ratio (9) Nonretroactive as of January 1, 

2024. O D

NUEMS Current Input (10) Nonretroactive as of January 

1, 2024. O D

Sensor Primary Current Rating (11) Nonretroactive as 

of January 1, 2024. O D

Kh or Kt (12) O D

Bi-directional (13) O D

Temperature Range if narrower than −20 °C to + 50 °C 

(− 4 °F to + 122 °F) (14) O D

R Required to be marked on the NUEMS

O Required to be marked on the NUEMS only if information is not available on a display

D Alternate when information is not marked physically on the NUEMS. If device identification and 

marking is provided on an electronic display, then all fields must be provided.

*

“Electronic Display” includes, but is not limited to, displays of the required marking information 

through a NUEMS display, a mobile device, or other electronic means as specified by the manufacturer 

and retrievable through the NUEMS. This may include providing access directly from the meter to a 

webpage. If the information is provided via a mechanism other than the NUEMS display, the 

mechanism must be provided by the device owner/operator as specified in UR.2.4.10. Devices for 

Viewing Marking Information Provided Via an Electronic Display, External Sensor (ES) NUEMS.

**Instructions on how to view required markings shall be marked on the device or provided in the NTEP 

CC.

General:

• Numbers appearing in parentheses (e.g., (1)) following each marking requirement above 

correspond to numbered descriptors in Table S.3.2.2.b. Descriptors for Table S.3.2.3.a. Device 

Identification and Marking Requirements of External Sensor (ES) NUEMS.

• For requirements and details on application, see Table S.3.2.3.b. Descriptors for Device 

Identification and Marking Requirements of External Sensor (ES) NUEMS.

Table S.3.2.3.b.

Descriptors for Device Identification and Markings Requirement of External Sensor (ES) NUEMS 

1. Manufacturer’s Identification. Marked per General Code paragraph G-S.1. Identification.

2. Manufacturer’s Model Prefix. For an External Sensor (ES) NUEMS having its NTEP number 

clearly identified, conspicuously and indelibly marked on the meter, where the NTEP certificate contains 

the complete marking details (including a description of the location and purpose of specific markings), 

the associated NUEMS is not required to meet General Code paragraph G-S.1. Identification (b)(1). 

3. Manufacturer’s Model Identifier. Marked per General Code paragraph G-S.1. Identification.

4. Serial Number Prefix. For an External Sensor (ES) NUEMS having its NTEP number clearly 

identified, conspicuously and indelibly marked on the meter, where the NTEP certificate contains the 

complete marking details (including a description of the location and purpose of specific markings), the 

associated NUEMS is not required to meet General Code paragraph G-S.1. Identification (c)(1).

5. Serial Number. Also see General Code paragraph G-S.1. Identification.
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6. NTEP Certificate of Conformance Number and Prefix. NUEMS electronics that has been evaluated 

by NTEP and has its own NTEP CC shall be marked per General Code paragraph G-S.1. Identification.

7. NUEMS Voltage Input Rating (Vnom). The nominal voltage input(s) for the voltage channel of the 

NUEMS electronics (e.g., 120VAC, 600VAC, 120-480VAC, etc.). Multiple forms of the term such as 

“Rated Voltage,” “Max Voltage,” and “Reference Voltage” are permitted.

8. Voltage Sensor (Vnom). The nominal input at the voltage sensor. If a voltage sensor is not used this 

marking is not required. If a voltage sensor is used, a multiplier can be used in place of Vnom and voltage 

sensor ratio.

9. Voltage Sensor Ratio. Ratio of sensor primary voltage to sensor output voltage. If a voltage sensor 

is not used this marking is not required. If a voltage sensor is used, a multiplier can be used in place of 

Vnom and voltage sensor ratio.

10. NUEMS Current Input (Input Inom or Imax). The nominal current or voltage input for the current 

channel of the NUEMS electronics. The output of the current sensor must match the input configuration 

of the meter.

11. Sensor Primary Current Rating (Sensor Inom). The nominal current input through the sensor.

12. Kh or Kt. Watthour test constant.

13. Bi-Directional. Marking via a “Separate Document” is permissible only if instructions for accessing 

that information is described in an accompanying NTEP Certificate of Conformance.

14. Temperature Range if Narrower Than − 20 °C to + 50 °C (- 4 °F to + 122 °F): If the device is rated 

for use over a range that is narrower than and within − 20 °C to + 50 °C (- 4 °F to + 122 °F), this must 

be physically and/or electronically marked.

S.3.3. Device Identification and Marking Requirements – External Sensors. – In addition to 

all the marking requirements of Section 1.10 General Code, paragraph G-S.1. Identification, 

each external sensor that is non-integral with the meter shall have the following conspicuously, 

legibly, and indelibly marked on a permanent identification label as shown in Table S.3.3.a. 

Device Identification and Marking Requirements - External Sensors and in Table S.3.3.b. 

Descriptors for Table S.3.3.a. Device Identification and Marking Requirements - External 

Sensors.

Table S.3.3a.

Device Identification and Marking Requirements - External Sensors

Physical Marking 

on Sensor

Electronic 

Display

Separate 

Document

(Hard Copy or 

Electronic)

Manufacturer name, initials, trademark 

(1) R D D

Model Prefix (2) O D D

Model (3) R D D

Serial Number Prefix “S/N” (4) O ‡ D ‡ D ‡

Serial Number (5) O ‡ D ‡ D ‡

NTEP CC Prefix and Number (6) O † D † D †

True Ratio (7) O D D

Maximum Primary Current (8) O D D
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Rated Frequency (Hz) (9) O D D

Maximum Safety Voltage Rating (10) O D D

Polarity (11) O D D

R Required to be marked on the device 

O Required to be marked on the device if information is not available on a display or in printed form

D Required when data is displayed on an electronic display or printed document

‡ Required only when a specific sensor must be matched to a specific meter input to meet accuracy 

specifications

† Required only when a sensor has separate approval from the metering system as a whole.

Notes:

• Numbers appearing in parentheses (e.g., (1)) following each marking requirement above 

correspond to numbered descriptors in Table S.3.3.b. Descriptors for External Sensor Marking 

Requirements.

• For requirements and details on application, see Table S.3.3.b. Descriptors for External Sensor 

Marking Requirements.

• “Electronic” includes, but is not limited to, displays of the required marking information 

through a NUEMS display, a mobile device, or other electronic means as specified by the 

manufacturer.

Summary:

When a NUEMS system is approved as a system, then the only hard marking required on sensors is the 

Manufacturer’s name and the Model Number, unless pairing a specific sensor to a specific NUEMS 

input is required, then the serial number is required.

Table S.3.3.b.

Descriptors for Device Identification and Marking Requirements - External Sensors

1. Manufacturer’s Identification. Marked per General Code paragraph G-S.1. Identification.

2. Manufacturer’s Model Prefix. The General Code paragraph G-S.1. Identification (b)(1) model 

prefix marking requirement for the sensor(s) may be met with a physical marking. Alternatively, 

the marking requirement may be satisfied through an electronic display or in a separate document 

accompanying the NUEMS provided that the NUEMS has its NTEP number clearly identified, 

conspicuously and indelibly marked on the meter, where the NTEP certificate contains the 

complete marking details (including a description of the location and purpose of specific 

markings).

3. Manufacturer’s Model. Marked per General Code paragraph G-S.1. Identification.

4. Serial Number Prefix. For a NUEMS having its NTEP number clearly identified, conspicuously 

and indelibly marked on the sensor(s), where the NTEP certificate contains the complete marking 

details (including a description of the location and purpose of specific markings), the associated 

sensor is not required to meet General Code paragraph G-S.1. Identification (c)(1).

5. Serial Number. Also see General Code paragraph G-S.1. Identification.

6. NTEP Certificate of Conformance Prefix and Number. A current sensor that has been evaluated 

separately by NTEP and has its own NTEP CC shall be marked per General Code paragraph GS.1. Identification.

7. True Ratio. The True Ratio, in primary amperes or volts to secondary amperes or volts shall be 

physically marked on a sensor unless it is contained in either electronic or printed documentation. 

This is to be expressed as xxxA:yyyA; or xxxA:yyyV; or xxxV:yyyV or a unit-less ratio. The 

number of digits is the number needed to express the values.
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Examples of sensor ratio markings include:

200A:5A

400A:0.3V

480V:120V

CT Turns Ratio 4:1

VT Ratio 4:1

An example of a sensor ratio designation which includes a unit-less ratio:

480V:120V = 4:1.

8. Maximum Primary Current. The maximum primary current at which the sensor can be safely 

and accurately operated.

9. Rated Frequency. A sensor shall be marked with its rated frequency if other than 40Hz to 400Hz.

10. Maximum Safe Operating Voltage. A sensor shall be marked with a Maximum Safe Operating 

Voltage if it is less than 600VAC.

Examples of sensor maximum safe operating voltage ratings:

• 250 Vac

• 250 VAC

• 50 V

Note: The maximum safe operating voltage rating marking may not be higher than the voltage 

to which the device was verified during type evaluation.

11. Polarity Marking. The sensor shall be marked to indicate proper orientation when the accuracy 

of the NUEMS is affected by orientation.

S.3.4. Abbreviations and Symbols. – When using abbreviations or symbols on a meter , sensor, 

or indicator, the following shall be used.

(a) FM = Form

(b) CL = Class

(c) V = Volts

(d) Hz = Hertz, Frequency or Cycles Per Second

(e) TA = Test Amperes

(f) Kh = Watthour Constant; Revolution or Pulse

(g) Rr = Register Ratio

(h) CSR = Current Sensor Ratio (may also be referred to as “current transformer ratio” or 

“CTR”)

(i) VTR or PTR = Voltage or Potential Transformer Ratio

(j) MULT BY = Multiply By

(k) W = wire (example: 240V 3W)

(l) Y = WYE Power Supply
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(m) IEEE = Institute of Electrical and Electronics Engineers

(n) B = Burden

(o) BIL = Basic Lightning Impulse Insulation Factor

(p) Kt = Watthour Test Constant

(q) AC = Alternating Current (i.e., VAC)

(r) J = Joule

(s) Wh = Watthour

(t) kWh = Kilowatt-hour

(u) ∆ = Delta Power Supply

(v) SD = Soft Data

(w) PD = Printable Data

N. Notes

N.1. NUEMS No-Load Test. – A NUEMS no-load test shall be conducted by applying rated voltage 

to the NUEMS under test and no current load applied. This test shall be conducted during type 

evaluation and may be conducted during field testing as deemed necessary. The test duration shall 

be ten minutes.

N.2. NUEMS Starting Load Test.– A NUEMS starting load test shall be conducted by applying rated 

voltage at a load of 0.25% of the Current Class (CL) or the Sensor Primary Current Rating at unity 

power factor. The rated voltage. The test shall be conducted during type evaluation and may be 

conducted during field testing as deemed necessary.

N.3. Minimum Test Duration. – Full and light load tests shall require at least a one-minute test and 

at least one watthour test constant.

N.4. NUEMS Test Loads.

(a) Internal Sensor (IS) NUEMS shall be balanced-load tested, and may be single-element tested, 

for NUEMS accuracy at full and light loads.

(b) External Sensor (ES) NUEMS shall be single-element tested for system accuracy at full and 

light loads. NUEMS testing shall be accomplished by applying the test load to the sensor(s) 

with the voltage circuits energized. When it is not feasible to test the system by injecting a 

primary current, testing using customer load shall be sufficient for field verification.

(c) The reference voltage phases (A, B, or C) at the NUEMS shall be the same phase as the load.

N.5. Test of a NUEMS.
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(a) Each NUEMS submitted for test shall have the necessary components required to test such 

as meter, sensor(s), indicators(s), system software, etc. Testing may be performed in the 

field.

(b) The test load applied for a full load test shall be 15 % of either the Current Class (CL) or the 

Sensor Primary Current Rating.

(c) The test load applied for a light load test shall be conducted at 1.5 % to 3 % of either the 

Current Class (CL) or the Sensor Primary Current Rating.

(d) The test load applied for a full load test of a NUEMS for a 0.5 power factor lagging setting 

shall be 15 % of either the Current Class (CL) or the Sensor Primary Current Rating. This 

test shall be conducted during type evaluation and may be conducted during in-service (field) 

or laboratory testing as deemed necessary.

(e) The test load applied for a light load test of a for a 0.5 power factor lagging setting shall be 

conducted at 3% to 6 % of either the Current Class (CL) or the Sensor Primary Current 

Rating. This test shall be conducted during type evaluation and may be conducted during inservice (field) or laboratory testing as deemed necessary.

(f) All tests shall be made at the rated voltage ± 10 %.

N.6. Repeatability Tests. – When conducted, tests for repeatability shall include a minimum of three 

consecutive tests at the same load, similar time period, etc. and be conducted under conditions where 

variations in factors are reduced to minimize the effect on the results obtained.

T. Tolerances

T.1. Tolerances, General.

(a) The tolerances apply equally to errors of underregistration and errors of overregistration.

(b) The tolerances apply to all electric energy measured at any load within the rated measuring 

range of the device.

(c) Where sensors or other components are used, the provisions of this section shall apply to the 

entire NUEMS.

T.2. No-Load Test. – For NUEMS with a Kt/Kh output, the NUEMS shall not emit more than one 

Kt/Kh pulse. For NUEMS without a pulse output, the register indication shall not change by more 

than 0.05 % of the energy at Current Class (CL) or the Sensor Primary Current Rating at unity 

power factor and rated voltage. Also see Note N.1. NUEMS No-Load Test.

T.3. NUEMS Starting Load Test. – The watthour test constant (Kt or Kh) output indications or 

register indication shall continue to advance. The purpose of this section is to verify that the NUEMS 

accumulates energy at the starting load.

T.4. Load Test Tolerances. – Tolerances for NUEMS shall be as shown in Table T.4. When it is not 

feasible to test the system by injecting a primary current, tolerances specified under “Tests 

Conducted at 0.5 Lagging Power Factor” shall apply.
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Table T.4.

Tolerances for NUEMS

Tests Conducted at Unity 

Power Factor

Tests Conducted at 0.5 

Lagging Power Factor

Acceptance Tolerances 1.0 % 2.0 %

Maintenance Tolerance 2.0 % 3.0 %

T.5. Repeatability. – When multiple load tests are conducted at the same load condition, the range 

of the load test results shall not exceed 25 % of the absolute value of the maintenance tolerance and 

the results of each test shall be within the applicable tolerance.

UR. User Requirements

UR.1. Selection Requirements.

UR.1.1. Customer Indicating Element, Accessibility. – For systems in which the primary 

indicating element is not reasonably accessible to the customer, such as one of the following shall 

be provided.

(a) Console display which is accessible to the customer on which the customer can 

unambiguously select the NUEMS output associated with this load.

(b) Remote display which is provided to customer as a part of the system.

(c) At the option of the customer, through an application that provides readings in real time.

UR.1.2. Submeter Required. – When a tenant is not directly served by the serving utility, and 

charges for electric energy are not included in the fixed periodic rent charges, a dedicated 

NUEMS that measures only the energy used at the discretion of the tenant shall be used.

UR.1.3. Suitability of Equipment. – A NUEMS shall be suitable for use on its electrical system.

UR.1.3.1. Service Applications. - A NUEMS shall accurately measure all loads 5 percent or 

greater of the electric service capacity of the tenant. Service capacity shall be determined by 

the master thermal overload protectors to the tenants’ service or by the rated capacity of the 

wiring and its circuits used to provide power from the service panel to the tenant.

AA MM MM = � [(PP VV ∗ CC CC CC )/11 ] ∗ HH HH

UR.1.3.2. Maximum Quantity-Value Division. - The maximum quantity-value division shall 

not exceed the minimum increment to be used in billing.

UR.1.4. Current Sensor. – The current sensor output shall be correctly matched to the meter 

current input.

UR.2.Installation Requirements.
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UR.2.1. Manufacturer’s Instructions. – A device shall be installed in accordance with the 

manufacturer’s instructions, and the installation shall be sufficiently secure and rigid to maintain 

this condition.

UR.2.2. Load Range. – A device shall be installed so that the current and voltage will not exceed 

the maximum continuous ratings of the NUEMS. Means to limit current and/or voltage shall be 

incorporated in the installation if necessary.

UR.2.3. Regulation Conflicts and Permit Compliance. – If any provision of this section (UR.2.

Installation Requirements) is less stringent than that required of a similar installation by the 

National Electrical Code®, as amended and adopted by the Local Authority having Jurisdiction, 

the installation shall be in accordance with the National Electric Code.

The installer of any new NUEMS service shall obtain all necessary permits and shall conform to 

all applicable regulations.

UR.2.4. NUEMS Installation Requirements.

UR.2.4.1. Certification. – It is the responsibility of the owner of a NUEMS to obtain written 

certification for each device from the appropriate regulatory agency.

The required certification shall meet the requirements of that agency and should identify the 

address, space, or number, of the premise served by the NUEMS connection; be signed by an 

agency representative; and shall clearly state the:

• installation is on a tariff schedule that qualifies for NUEMS use,

• billing format, rates, and charges conform to all applicable tariff rules,

• date of such determination, and 

• designee’s name and title if performed by a designee, and 

The certification shall be provided prior to a NUEMS being used for commercial purposes.

UR.2.4.2. NUEMS Test Features. – All NUEMS shall be provided with test features to 

facilitate common tests methods used in the electrical submetering industry.

UR.2.4.3. Safety Mechanism. – NUEMS installations that are equipped with current 

transformers with a current output that is not self-limiting shall have a mechanism installed 

to allow the meter to be connected to or removed for safe testing without the risk of dangerous 

voltages that can result from secondary open circuit CTs.

UR.2.4.4. Metered Circuits (Submeter Load Service). – For NUEMS with separate line and 

load service connections, all electricity used by a tenant shall be taken exclusively from the 

load service of the tenant's NUEMS. This service and its associated NUEMS shall accurately 

measure the tenant's load and be capable of being used only at the discretion of the tenant.

UR.2.4.5. Dedicated Tenant NUEMS Service. – A NUEMS shall serve only the space, lot, 

building, room, suite, stall, slip, or premise occupied by the tenant.
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UR.2.4.6. NUEMS Tenant Premise Identification. – Tenant premise identification shall be 

clearly and permanently shown on or at the NUEMS, and on all separate components of a 

NUEMS, including, but not limited to, current sensor(s), modem(s), and transmitter(s) if 

equipped. Remote indications and all printed indications shall be readily identifiable and 

readily associated with the tenant’s premise. Printed indications shall also include time and 

date information. For field configured systems the information shall be after actual 

configuration is established.

UR.2.4.7. Devices for Viewing Marking Information Provided Via an Electronic Display, 

External Sensor (ES) NUEMS. – When required markings are provided via an electronic 

display the owner/operator of the NUEMS is responsible for providing means for viewing this 

information on the site at the time of inspection or on request. See also Table S.3.2.3.a. Device 

Identification and Marking Requirements for External Sensor (ES) NUEMS.

UR.2.4.8. External Sensors Located Remotely From the Pulse Output or Display. - If the 

NUEMS is installed in such a way that testing cannot be conducted by a single inspector from 

a reasonable testing position, then means shall be provided to allow the pulse output or 

display to be remotely used at the sensor location. For example, a portable device that 

receives the pulse by radio/WiFi and provides the pulse as a dry contact closure to the test 

equipment.

UR.3. Use of Device.

UR.3.1.Recorded Representations. – A record, either printed or electronic, providing the 

following information on electrical energy usage shall be available at the end of the billable 

interval:

(a) the total quantity of the energy delivered with unit of measure;

(b) the total computed price of the energy sale;

(c) the unit price of the energy.

For systems capable of applying multiple unit prices for energy during the billable interval, the 

following additional information is required:

(1) A schedule of the rate time periods and the unit price applied for each

(2) the total quantity of energy delivered during each;

(3) the total purchase price for the quantity of energy delivered during each rate time period.

Appendix D. Definitions

The following definitions are proposed for addition to NIST Handbook 44 Appendix D, Definitions 

at the time when the status of this Tentative Code is changed from “tentative” to “permanent.” Until 

such time that the status of the code is designated as “permanent,” these proposed definitions will

remain in this section of the Tentative Code.
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The specific code to which the definition applies is shown in [brackets] at the end of the definition. 

Definitions for the General Code [1.10] apply to all codes in Handbook 44.

A

active energy. – The integral of active power with respect to time. Typically measured in units of 

kilowatt-hours (kWh), or watt-hours.

EE(TT) = � vv( ) ∙ ( ) ∙ dd

TT

00 Eq. 1

Where T is much greater than the period of the AC line frequency.

alternating current (AC). – An electric current that reverses direction in a circuit at regular intervals. 

[3.XX]

ampere. – The practical unit of electric current. It is the quantity of current caused to flow by a 

potential difference of one volt through a resistance of one ohm. One ampere is equal to the flow of 

one coulomb of charge per second. One coulomb is the unit of electric charge equal in magnitude to 

the charge of 6.24 x 1018 electrons. [3.XX]

audit trail. – An electronic count and/or information record of the changes to the values of the 

calibration or configuration parameters of a device. [1.10, 2.20, 2.21, 2.24, 3.30, 3.37, 3.39, 3.XX, 

5.56(a)]

(Added 1993)

B

balanced load. – Balanced load is used to indicate equal currents in all phases and relatively equal 

voltages between phases and between each phase and neutral (if one exists); with approximately equal 

watts in each phase of the load. [3.XX]

basic lightning impulse insulation level (BIL). – A specific insulation level expressed in kilovolts of 

the crest value of a standard lightning impulse. (Example: BIL = 10 Kv) [3.XX]

burden (B). – The impedance of the circuit connected to the instrument transformer's secondary 

winding. (Example: B = 21 Ohms Max) [3.XX]

C

calibration parameter. – Any adjustable parameter that can affect measurement or performance 

accuracy and, due to its nature, needs to be updated on an ongoing basis to maintain device accuracy, 

e.g., span adjustments, linearization factors, and coarse zero adjustments. [2.20, 2.21, 2.24, 3.30, 3.37, 

3.39, 3.XX, 5.56(a)]

(Added 1993)

configuration parameter. – Any adjustable or selectable parameter for a device feature that can affect 

the accuracy of a transaction or can significantly increase the potential for fraudulent use of the 

device and, due to its nature, needs to be updated only during device installation or upon replacement 
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of a component, e.g., division value (increment), sensor range, and units of measurement. [2.20, 2.21, 

2.24, 3.30, 3.37, 3.XX, 5.56(a)]

(Added 1993)

current. – The rate of the flow of electrical charge past any one point in a circuit. The unit of 

measurement is amperes or coulombs per second. [3.XX]

current class (CL). – For self-contained meters, the manufacturer's designated maximum rated 

current a NUEMS can measure continuously without damage and without exceeding limits of 

accuracy. (Example: CL 200) [3.XX]

current sensor. - A device able to measure and output analog or digital representations of one or 

more currents. Examples of current sensors are current transformers, low-voltage current 

transducers, and Rogowski coils. (OWM is seeking written permission from National Electrical 

Manufacturers Association (NEMA) to reprint . Oral permission was received.)

E

element. – A combination of a voltage-sensing unit and a current-sensing unit, which provides an 

output proportional to the quantities measured. Meters can include multiple elements based on 

service type. For mechanical meters, this is also referred to as a “stator.” (OWM is seeking written 

permission from National Electrical Manufacturers Association (NEMA) to reprint . Oral permission 

was received.) [3.XX]

energy flow. – The flow of energy between line and load terminals (conductors) of a NUEMS. Flow 

from the line to the load terminals is considered energy delivered. Energy flowing in the opposite 

direction (i.e., from the load to line terminals) is considered as energy received. [3.XX]

equipment, commercial. – Weights, measures, and weighing and measuring devices, instruments, 

elements, and systems or portion thereof, used or employed in establishing the measurement or in 

computing any basic charge or payment for services rendered on the basis of weight or measure. As 

used in this definition, measurement includes the determination of size, quantity, value, extent, area, 

composition (limited to meat and poultry), constituent value (for grain), or measurement of 

quantities, things, produce, or articles for distribution or consumption, purchased, offered, or 

submitted for sale, hire, or award. [1.10, 2.20, 2.21, 2.22, 2.24, 3.30, 3.31, 3.32, 3.33, 3.34, 3.35, 3.38, 

3.XX, 4.40, 5.51, 5.56.(a), 5.56.(b), 5.57, 5.58, 5.59]

(Added 2008)

event counter. – A nonresettable counter that increments once each time the mode that permits 

changes to sealable parameters is entered and one or more changes are made to sealable calibration 

or configuration parameters of a device. [2.20, 2.21, 3.30, 3.37, 3.39, 3.XX, 5.54, 5.56(a), 5.56(b), 5.57]

(Added 1993)

event logger. – A form of audit trail containing a series of records where each record contains the number 

from the event counter corresponding to the change to a sealable parameter, the identification of the 

parameter that was changed, the time and date when the parameter was changed, and the new value of 

the parameter. [2.20, 2.21, 3.30, 3.37, 3.39, 3.XX, 5.54, 5.56(a), 5.56(b), 5.57]

(Added 1993)
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F

form designation (FM). –An alphanumeric designation denoting the circuit arrangement for which 

the NUEMS is applicable and its specific terminal arrangement. The same designation is applicable 

to equivalent NUEMS for all manufacturers. (Example: FM 2S) [3.XX]

H

hertz (Hz). – Frequency or cycles per second. One cycle of an alternating current or voltage is one 

complete set of positive and negative values of the current or voltage. [3.XX]

K

kilowatt (kW). – A unit of power equal to 1,000 watts. [3.XX]

kilowatt-hour (kWh). – A unit of energy equal to 1,000 watthours. [3.XX]

L

line service. – The service terminals or conductors connecting the (NUEMS) to the power source. 

[3.XX]

load service. – The service terminals or conductors connecting the (NUEMS) to the electrical load 

(e.g., vehicle, tenant, etc.). [3.XX]

load, full. – A test condition with rated voltage, current at 100% of test amps level, and power factor 

of 1.0. [3.XX]

load, light. – A test condition with rated voltage, current at 10% of test amps level, and power factor 

of 1.0. [3.XX]

M

master meter, electric. – A (NUEMS) owned, maintained, and used for commercial billing purposes 

by the serving utility. All the electric energy served to a submetered service system is recorded by the 

master meter. [3.XX]

metrological components. – Elements or features of a measurement device or system that perform 

the measurement process or that may affect the final quantity determination or resulting price 

determinations. This includes accessories that can affect the validity of transactions based upon the 

measurement process. The measurement process includes determination of quantities; the 

transmission, processing, storage, or other corrections or adjustments of measurement data or 

values; and the indication or recording of measurement values or other derived values such as price 

or worth or charges. [3.XX]

N

non-utility electricity measuring system (NUEMS). – An electricity measuring system comprised 

of all the metrologically relevant components required to measure electrical energy, store the 
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result, and report the result used in non-utility sales of electricity wherein the sale is based in whole 

or in part on one or more measured.

O

ohm. – The practical unit of electric resistance that allows one ampere of current to flow when the 

impressed potential is one volt. [3.XX]

P

percent error. – Percent error is calculated as follows: 

percent error = (NUEMS reading – standard reading)/standard reading x 100

[3.XX]

power factor (PF). – The ratio of “active power” to “apparent power” in an AC circuit. It describes the 

efficient use of available power. [3.XX]

primary indicating or recording elements. – The term “primary” is applied to those principal 

indicating (visual) elements and recording elements that are designed to, or may, be used by the 

operator in the normal commercial use of a device. The term “primary” is applied to any 

element or elements that may be the determining factor in arriving at the sale representation 

when the device is used commercially. (Examples of primary elements are the visual indicators 

for meters or scales not equipped with ticket printers or other recording elements and both the 

visual indicators and the ticket printers or other recording elements for meters or scales so 

equipped.) The term “primary” is not applied to such auxiliary elements as, for example, the 

totalizing register or predetermined-stop mechanism on a meter or the means for producing a 

running record of successive weighing operations, these elements being supplementary to those 

that are the determining factors in sales representations of individual deliveries or weights. (See 

“indicating element” and “recording element.”) [1.10, 3.XX]

R

reactive power. – For sinusoidal quantities in a two-wire circuit, reactive power is the product of 

the voltage, the current, and the sine of the phase angle between them, using the current as the 

reference. [3.XX]

register ratio (Rr). – The number of revolutions of the gear meshing with the worm or pinion on 

the rotor shaft per complete rotation of the fastest (most sensitive) wheel or dial pointer. [3.XX]

remote configuration capability. – The ability to adjust a weighing or measuring device or change 

its sealable parameters from or through some other device that is not itself necessary to the 

operation of the weighing or measuring device or is not a permanent part of that device.[2.20, 2.21, 

2.24, 3.30, 3.37, 3.39, 3.XX, 5.56(a)]

(Added 1993)

retail device. – A measuring device primarily used to measure product for the purpose of sale to the 

end user. [3.30, 3.32, 3.37, 3.39, 3.XX]

(Amended 1987 and 2004)
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S

sensor ratio. – The stated ratio of the primary circuit current or voltage compared to the secondary 

circuit current or voltage. (Example: CSR = 200 : 0.1) [3.XX]

serving utility. – The utility distribution company that owns the master meter and sells electric 

energy to the owner of a submeter system. [3.XX] 

starting load. – The minimum load above which the device will indicate energy flow continuously. 

[3.XX]

submeter. – A meter or meter system downstream of the electric master meter. [3.XX]

T

tenant. – The person or persons served electric energy from a non-utility electricity-measuring 

system (NUEMS). [3.XX]

test amperes (TA). – The full load current (amperage) specified by the device manufacturer for 

testing and calibration adjustment. (Example: TA 30). [3.XX]

thermal overload protector. – A circuit breaker or fuse that automatically limits the maximum 

current in a circuit. [3.XX]

U

unit price. – The price at which the product is being sold and expressed in whole units of 

measurement. [1.10, 3.30, 3.XX]

(Added 1992)

utility. – A corporation, person, agency, authority, or other legal entity or instrumentality aligned 

with distribution facilities for delivery of electric energy for use primarily by the public. Included 

are investor-owned electric utilities, municipal and State utilities, Federal electric utilities, and 

rural electric cooperatives. A few entities that are tariff based and corporately aligned with 

companies that own distribution facilities are also included.

A list of recognized utilities in the U.S. can be found at the U.S. Energy Information Administration 

(EIA) at: https://www.eia.gov/electricity/data/eia861 [3.XX]

V

volt. – The practical unit of electromotive force. One volt will cause one ampere to flow when 

impressed across a resistance of one ohm. [3.XX]

W

watt. – The practical unit of electric power. In an alternating-current circuit (AC), the power in 

watts is volts times amperes multiplied by the circuit power factor. [3.XX]
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watthour (Wh). – The practical unit of electric energy, which is expended in one hour when the 

average power consumed during the hour is one watt. [3.XX]

meter – self-contained. – A meter in which the terminals are arranged for connection to the circuit 

being measured without using external instrument transformers. [3.XX]

watthour constant (Kh). – The expression of the relationship between the energy applied to the 

meter and the output indication, expressed as “watthours per revolution” or “watthours per output 

indication.” [3.XX]

watthour test constant (Kt). – The expression of the relationship between the energy applied to the 

meter and the output indication, expressed as “watthours per output indication,” when the meter is 

in test mode [3.XX]

NIST OWM Detailed Technical Analysis: 

The USNWG on Electric Vehicle Fueling & Submetering is divided into two subgroups; one to address 

electric vehicle fueling and one to address utility-type watt hour meters. This item addresses work being 

done by the latter subgroup, the Watthour Type Electric Meters Subgroup (WHE SG).

Since 2016, the EWH SG has been developing a proposed NIST Handbook 44 code for WHE-type 

meters. This item has been on the S&T Committee’s agenda since 2016 as a Developing Item to allow 

the USNWG to inform the weights and measures community of progress on the draft code.

The WHE SG appreciates the Committee’s willingness to maintain the item on the agenda as a 

mechanism for and to encouraging input and participation from those interested in the draft code and 

associated work. 

The WHE SG is pleased to submit a draft NIST HB44 code for “Non-Utility Electricity Measuring 

Systems” to the S&T Committee Chair on November 12, 2022 for consideration at the 2023 NCWM 

Interim Meeting. The WHE SG believes the draft code is ready for consideration as a voting item and 

asks the Committee to consider assigning this item “Voting” status.

At the 2023 NCWM Interim Meeting, Tina Butcher commented there are some areas of the code in which 

the Subgroup is continuing to develop some additional language; however, this work need not delay 

consideration of the Code.

The Subgroup would also like to call attention to some specific areas of the Code as noted below and is 

open to suggested changes by the Committee as comments are received on this item.

• Paragraph S.1.3.2. Test Output.

 The Subgroup voted several times on the language in this paragraph and the majority of 

members supported this language. However, the regulatory members of the Subgroup 

disagreed with this language. Thus, the Subgroup would especially appreciate review and 

comments on this paragraph.

• Table S.3.2.3.b., Note 7:
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 The Subgroup is considering the development of an accompanying new User Requirement 

related to the marking of the service voltage. This would be presented as a future 

recommendation to the draft code.

• N.3. Minimum Test Duration:

 The Subgroup is considering alternative language for this paragraph that would include more 

specificity regarding the full and light load tests. The Subgroup will offer any such 

recommendations for changes to the Committee to consider along with any other comments 

the Committee might receive from NCWM members.

• N.5.(a) Test of NUEMS:

 The Subgroup is considering moving N.5.(a) out of the Notes section and moving it to a User 

Requirement (with corresponding changes to present it as a User Requirement) as follows and 

is interested in input on this suggestion:

• UR.X.X. Each NUEMS submitted for testing shall have all necessary components 

assembled, connected, and configured as intended for use. Components may include, but 

are not limited to, meter, sensor(s), indicator(s), etc.

All the Regions reviewed this item at their 2022 fall Regional Association Meetings they have 

recommended a Developing status; however, this assessment was based on the prior version of the draft 

code and comments received up to that point.

Although the most recent draft of the code was not available until after the Fall 2022 Regional 

Association Meetings, the regions and others will have adequate opportunity to review and comment on 

the draft in the period between the 2023 NCWM Interim and Annual meetings.

Thus, the WHE SG believes that designating this item with a Voting status is still an appropriate course of 

action.

At the WHE SG meeting on April 25, 2023, the SG agreed to move forward the following changes to the 

definition in the code.

Bidirectional. – A NUEMS equipped to register the accumulation of energy in both directions (i.e., for 

delivered and received energy):

A bidirectional NUEMS shall fall into at least one of the following categories: 

(a) Single register or net meter that displays the difference between the delivered and received 

energy; or

(b) Separate register(s) for delivered or received. 

external sensors. – Any voltage or current sensors not located inside of the meter body NEUMS itself 

and not inside the sealed enclosure containing the NEUMS

internal sensors. – Any voltage or current sensors located inside of the meter body NEUMS itself or 

inside the sealed enclosure containing the NEUMS. 
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non-integral. – Used to describe external sensors that can be disconnected from the meter body.

At the WHE SG meeting on June 27, 2023, the SG agreed to move forward the following changes to the 

definition in the code.

S.1.3.2. Test Output. – Each A NUEMS within a system shall have either: (1) a location for the 

reading of the accumulated valuea rotating disk indicator; (2) an electrical pulse output (visible 

and/or infrared pulse), or (3) an electrical pulse output (in the form of a closure (relay or electronic 

means), which provides a pulse at an interval of with Kt or KhWatt-Hours per pulse; or (3) other 

means for viewing accumulated values. The value of Kt or Kh shall be such that the NUEMS’s 

accuracy can be tested in 5 minutes or less for any specified specific test condition.

S.1.3.6. NUEMS With External Sensors Located Remotely from the Pulse Test Output or 

Display. – For NUEMS with external sensors located remotely from either the pulse test output or 

display which can be installed as described in paragraph UR.2.4.8. External Sensors Located Remotely 

from the Pulse Test Output or Display, means shall be provided to allow either the pulse test output 

or display to be remotely used.

12. True Ratio.

True Ratio. The True Ratio, in primary amperes or volts to secondary amperes or volts shall be 

physically marked on a meter unless it is contained in either electronic or printed documentation. 

This is to be expressed as xxxA:yyyA; or xxxA:yyyV; or xxxV:yyyV. The number of digits is the 

number needed to express the values.

Examples of sensor ratio markings include:

200A:5A

400A:0.3V

480V:120V

T.2. No-Load Test. – For A NUEMS with a Kt/Kh output, the NUEMS shall not emit more than 

one Kt/Kh test pulse output. For NUEMS without a pulse output, the register indication shall not 

change by more than 0.05 % of the energy at Current Class (CL) or the Sensor Primary Current 

Rating at unity power factor and rated voltage. Also see Note N.1. NUEMS No-Load Test.

N.3. NUEMS Minimum Test Duration. – A NUEMS fFull load test shall consist of a minimum 

of 10 watthour test constants and a light load tests shall require at least a one-minute test and at

least consist of a minimum of one watthour test constant.

Some additional areas that we would like to note to the S&T Committee:

• The “Source” should read NIST U.S. National Work Group (USNWG) Watthour Type Electric 

Meters Subgroup (WHE SG).

• The title of this Item should read “Non-Utility Electricity-Measuring Systems (NUEMS) –

Tentative Code ”

• Most members supported the proposed language as it currently appears in the 2023 S&T Agenda 

(Pub. 16), although regulatory members of the SG disagreed with the proposed language. 
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• In addition, the regulatory members provided a detailed list to the WHE SG of their concerns. 

These concerns are noted in the letter that NCWM received from the California Agricultural 

Commissioners and Sealers Association (CACASA) (dtd. June 29, 2023) and posted under the 

NCWM S&T Supporting document website.

• The WHE SG attempted to address the regulators and CACASA concerns. They made headway 

in addressing those concerns and they appear in the Crosswalk below. 

• The Crosswalk below, provides updates of items that appear in the 2023 S&T Annual Agenda 

(Pub. 16). They represent changes the WHE SG voted on to move forward to the S&T 

Committee for consideration. Due to limited time, the WHE SG was not able to address all the 

items, and the work continues.

Summary of Discussions and Actions:

At the NCWM 2022 Interim Meeting, Matt Douglas (California – Division of Measurement Standards) 

stated that California supports the development of this item but has concerns about identity marking 

requirements being on a separate document. Also, the devices should be easy to test before and after 

installation. This device should allow for electronic data logger. Juana Williams commented that the 

subgroup had provided a draft code that is on the website. Juana Williams requested comments be 

submitted to Tina Butcher (NIST OWM) or Lisa Warfield by March 22, 2022. Juana Williams stated 

these comments will be used to provide and updated draft for the 2022-2023 submission cycle and the 

item remain in developing status. The Committee agreed that the item be given a Developing status.

At the NCWM 2022 Annual Meeting, the Committee heard an update from Tina Butcher highlighted the 

points in the Executive Summary to this item. Tina Butcher acknowledged this item has been on the 

agenda for several years, during which time the SG has been continually working to develop a draft code 

for submission to the NCWM for consideration. The SG shared a draft with the Committee in August 

2021 and asked that it be posted to the NCWM website. The SG had identified specific sections of the 

draft code which was still being refined by the SG. The SG had asked that that those interested in this 

work review the remainder of the code and provide input that would allow the SG an opportunity to 

modify the draft to reflect their comments prior to submitting a final recommendation to the NCWM.

Tina Butcher reported that the SG is diligently continuing to work on this item, holding eighteen meetings 

in 2021 and seven meetings in 2022. They thanked those who provided comments during the regional 

and national meetings, noting in particular the Committee heard from California Division of Measurement 

Standards who noted that additional work is needed on the marking requirements. Tina noted that 

California and others have raised questions about the provision that would allow required markings to 

appear on a separate document and asked for clarifications on how this would work. Other concerns 

raised included making sure that testing capabilities are readily achievable both before and after 

installation and refining requirements for audit trail requirements to ensure that hard copies of any event 

loggers are available to the inspector. The SG appreciates this input and is working to resolve the 

remaining areas of concern identified and hopes to present a draft to the NCWM in the coming fall.

The Committee agreed to retain this item on its agenda with a Developing status while the SG continues 

its work.

At the NCWM 2023 Interim Meeting, Tina Butcher commented that the USNWG on Watthour Type 

Electric Meters Subgroup believes that the draft code is ready for consideration as a voting item. Tina 
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Butcher asked for continued feedback from the weights and measures community. During the Committee 

work session, the Committee agreed that the item is fully developed and has merit and assigned the item a 

Voting status.

At the NCWM 2023 Annual Meeting, Henry Alton (METERGY) spoke as a member of industry and a 

member of the workgroup. They stated the item is ready for a vote and it has been worked on by the 

members of the workgroup, including regulators. The commentator referred to a letter of support submitted 

to the committee which was posted on NCWM website.

Andrew Kimura (Santa Cruz County, CA) requested the de-escalation of the item from voting to 

developing. The commentator noted the regulators on the work group were not in agreeance with the final 

draft of the agenda item. Andrew provided feedback on specific areas and presented a PowerPoint during 

open hearing. Andrew Kimura stated the final draft of the agenda item does not address concerns by 

regulators. The commentator requested the work group consult with regulators to address specific concerns 

as presented during open hearings and in a letter submitted by the California Agricultural Commissioner 

and Sealers Association (CACASA). Andrew commented there is no intent to delay the item any further 

but expressed the need to develop the item further to address regulators concerns.

Matthew Douglas (Division of Measurement Standards, California) referenced the letter submitted by 

California Agricultural Commissioner and Sealers Association (CACASA) and requested de-escalation of 

the item from voting to developing. Mathew requested the work group work with regulators for further 

development.

Jose Arriaga (Orange County, CA) and Austin Shepard (San Diego County, California ) requested the deescalation of the item from voting to developing and requested the work group work closely with regulators 

for further development.

The Committee agreed with many of the comments heard during open hearings and decided to downgrade 

the item to Informational prior to the Voting Session. The Committee was notified the Task Group was no 

longer working on this specific item as it has considered it fully developed. The Committee believes the 

Informational status will allow for further development of the item through the S&T Committee. 

The Committee received written comments from Andrew Kimura, who presented during open hearings. 

Written comments included specific, proposed changes to the item which were referred to in open hearings 

and that were represented in the letter submitted by CACASA. The Committee heard from a member of 

industry in support of the item and considered the National Electrical Manufactures Association (NEMA) 

presentation posted on NCWM’s website. 

The Committee considered the edits submitted by Andrew Kimura and cross-referenced those changes to 

the NIST OWM sponsored Watthour Type Electric Meters Subgroup – Recommended Crosswalk. The 

Committee has decided to incorporate the recommended edits from NIST OWM’s crosswalk into the item 

under consideration to be forwarded to the regions. Additional changes recommended by Andrew Kimura 

are available for review on the NCWM website.
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Regional Association Reporting:

Western Weights and Measures Association

At the 2022 WWMA Annual Meeting, no comments were heard on this item. The WWMA S&T 

Committee recommended that this item should remain Developing to allow the USNWG to continue 

development of the model code. 

At the 2023 WWMA Annual Meeting, the proposed language for consideration is posted on the WWMA 

website, Events – Meeting Documents – OTH-16.1 Recommended Edits Agenda Item. Comments heard 

on the floor were regarding the proposed updated language.

Austin Shepard (San Diego County California) supports this item moving forward as a Voting item with 

the proposed changes as posted on the WWMA website.

Due to the substantial changes to the proposed language the WWMA S&T Committee recommends this 

item remain Informational to allow the body of the NCWM the opportunity to review those proposed 

changes and provide feedback to the NCWM S&T Committee. The Committee further recommends the 

NCWM S&T Committee consider the updates provided by Andrew Kimura (Santa Cruz County 

California) in their deliberations.

Updated language will be included in the WWMA S&T Committee 2023 Final Report as an Appendix to 

the item.

Southern Weights and Measures Association

At the 2022 SWMA Annual Meeting, Lisa Warfield stated the workgroup planned to have an item in 

NCWM Publication 15 before the 2023 NCWM Interim Meeting. 

The SWMA S&T Committee recommended this item remain as a Developing Item. 

At the 2023 SWMA Annual Meeting, they remarked that Andrew Kimura (Santa Cruz County, 

California) submitted a letter detailing many recent changes to this item ahead of our Annual Meeting.

Lisa Warfield, OWM, asked the Committee if they were considering the printed language or the language 

submitted by Andrew Kimura at the NCWM Interim.

The Committee will consider this item with Andrew Kimura’s most recent revisions.

The Committee recommends this item remain an Informational item, so that the NCWM S&T Committee 

can continue to develop it with the opportunity to escalate it to Voting status after the NCWM Interim 

Meeting.

Northeastern Weights and Measures Association

At the 2022 NEWMA Interim Meeting, Lisa Warfield commented that NIST is still working on this item. 

An update will be available for the NCWM Interim Meeting. 

The Committee is recommending that this item retain a Developing status. After hearing comments from 

the floor, the Committee recognized the need to further develop this item and recommended the item 

retain Developing status.
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At the 2023 NEWMA Annual Meeting, the Committee heard no comments on this item but 

recommended to the body that this item retain a Developing status. The body concurred.

At the 2023 NEWMA Interim Meeting, no comments were heard on this item and the Committee does 

not have a recommendation.

Central Weights and Measures Association

At the 2022 CWMA Interim Meeting no comments were heard from the floor. The CWMA S&T 

Committee recommended this as a Developing Item.

At the 2023 CWMA Annual Meeting, no comments were heard from the floor. The CWMA S&T 

Committee recommended this as a Voting Item.

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Informational.

OTH-24.1 Appendix D, Definitions: liquefied petroleum gas retail motor-fuel device.

Source: National Propane Gas Association

Submitter’s Purpose and Justification:

The proposal is a companion to the main proposal to modify 3.32, S.2.5.1 and S.2.5.2. There is another 

proposal that will substitute the term “liquefied petroleum gas retail motor-fuel device” for the terms 

“retail motor-fuel dispenser” and “retail motor-fuel device” throughout 3.32.

This proposal reflects the intent of U-Haul International, Inc. and the National Propane Gas Association’s 

Technology, Standards and Safety Committee, a volunteer organization comprised of 2500+ members, 

including propane retail marketers and others providing products or services to the propane industry.

This is a companion to this group’s proposal to 3.32, S.2.5.1 and S.2.5.2. The proposed change to the 

definition will more precisely define what a liquefied petroleum gas retail motor-fuel device is. This is a 

UL-listed device that is electricity-powered and that has all of the features required by Handbook 44. It 

includes a safety nozzle that connects to the fill valve on the vehicle which will not flow gas unless a 

positive connection is made. These devices are required by NFPA 58 for all LP-gas dispensers installed at 

refueling facilities open to the public.

Opposition would most likely come from those opposed to the primary changes in S.2.5.1 and S.2.5.2. 

Opposition may also come from those concerned about vehicles that do not have the K15 mating 

connection on the fill valve of the vehicle. Rebuttal to that would be that propane industry sources 

indicate that older vehicles that do not have the K15 connection are being retrofit at a high rate to 

incorporate the safety features of the K15 connection.

The submitter requested Voting status in 2024.
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NIST OWM Executive Summary for OTH-24.1 – Appendix D, Definitions: liquefied petroleum gas 

retail motor-fuel device.

NIST OWM Recommendation: Withdrawn

• If the item remains as proposed it should be withdrawn or be assigned a developing status.

• The reference to Section 3.32. at the end of the definition should not be stricken.

• OWM opposes limiting this definition to those devices that have a K15 nozzle as it is only 

required on “self-service engine fuel dispensers” per NFPA 58, 6.28.5.2. 

• Currently all dispensers used to deliver LPG as a motor vehicle fuel installed after January 1, 

2017 are required to have a zero-setback interlock as required on devices that dispense other 

types of fuels into motor vehicles.

• A search of the NCWM website indicates that there are various retail motor-fuel dispensers 

designed to dispense LPG that have an NTEP CC and are suitable for this purpose. Those 

installed after January 1, 2017 are currently required to have a zero-setback-interlock.

• This item should be blocked with LPG-24.1 and LPG-24.2 if they remain on the agenda.

Table 2. Summary of Recommendations

OTH-24.1 – Appendix D, Definitions: liquefied petroleum gas retail motor-fuel device.

Status Recommendation Note* Comments

Submitter Voting

OWM Withdrawn

WWMA Developing

NEWMA Developing

SWMA Developing

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda
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5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44 Appendix D, Definitions as follows:

liquefied petroleum gas retail motor-fuel device. – A device designed for the measurement and 

delivery of liquefied petroleum gas used as a fuel for internal combustion engines in vehicles bearing 

a state or federal license plate for use on public roads. The device can be operated either by 

trained personnel or the customer. The term means the same as “retail motor-fuel dispenser” 

and “retail motor-fuel device” as it appears in section 3.32 LPG and Anhydrous Ammonia 

Liquid-Measuring Devices. [3.32]

Note: These devices are required to be listed to UL 495 Power-Operated Dispensing Devices for LP-Gas 

and equipped with a Type K15 nozzle in accordance with ISO/DIS 19825, Road vehicles - Liquefied 

petroleum gas refueling connector.

(Amended 20XX)

NIST OWM Detailed Technical Analysis: 

NIST OWM did not provide a detailed analysis for this item.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this item 

as Voting item blocked with Item LPG 24.1.

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting comments were heard on LPG-24.1, LPG-24.2, and OTH-24.1 

collectively:

There was consensus of support for the items and a request to Block the three items. There were 

comments that this may be an opportunity to clarify existing language in NIST HB 44 which some find 

confusing, and possibly merging S.2.5.1. and S.2.5.2. A question was also posed to the body to address 

the intent of the item by exempting analog devices from a Zero Set Back Interlock requirement.

Based on the comments heard during the open hearings, the WWMA S&T Committee recommends this

item be Blocked with LPG-24.1 and LPG-24.2 and the Blocked items be assigned a Developing status to 

allow the body an opportunity to review the new language and allow the submitter to address the 

comments heard during open hearings.
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Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, the Committee heard no comments on this item during Open 

Hearings.

The Committee supports the modification of the definition for Liquefied Petroleum Gas Retail MotorFuel Device and recommends blocking this item with LPG-24.1 and LPG-24.2. and moving this group of 

items forward with a Developing status.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, New York, New Jersey, and Massachusetts recommended this 

item be developing as it is a companion to LPG-24.1. Upon consensus of the body, the Committee 

recommends this item be Developing.

OTH-24.2 Appendix D, Definitions: National Type Evaluation Program (NTEP) and 

Certificate of Conformance (CC)

Source: Jerry Buendel

Submitter’s Purpose and Justification:

Add a definition of Certificate of Conformance (CC) and a definition of National Type Evaluation 

Program (NTEP) to Handbook 44, Appendix D.

• The term National Type Evaluation Program (NTEP) is used in the General, Scales, Automatic 

Weighing System, Hydrogen Gas-Measuring, Electric Vehicle Fueling Systems, Grain Moisture 

Meter, Near-Infrared Grain Analyzers, and Multiple Dimension Measuring Devices codes, and in 

Appendix A. Fundamental Considerations. 

• Some users of the Handbook, including regulatory officials, have little or no knowledge of NTEP 

and the significance of Certificates of Conformance.

• The terms NTEP and Certificate of Conformance appear in NCWM’s Basic Competency, 

Professional Certification, and Service Agent examinations. Examinees are expected to be able to 

understand NTEP CCs and apply information found on the CCs.

• The definition for NTEP and CC are taken from NIST Handbook 130, Uniform Regulation for 

National Type Evaluation. The statements on inactive CCs are taken from the NCWM website, 

NTEP Frequently Asked Questions page.

• The absence of definitions could cause enforcement or other legal issues.

The submitter requested Voting status for 2024.
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NIST OWM Executive Summary for OTH-24.2 – Appendix D, Definitions: National Type 

Evaluation Program (NTEP) and Certificate of Conformance (CC)

NIST OWM Recommendation: Voting with the following suggested edits:

• In the proposed definition of Certificate of Conformance (CC) OWM suggests the following 

editorial changes:

• Replace “testing” with “evaluation” as labs do more than just test devices.

• Replace “a Participating” with “an authorized” or similar terms to recognize that some 

CC’s will be issued by the NCWM NTEP lab.

• Replace “test procedures” with “relevant provisions” as Pub 14 includes procedures 

for evaluation other than test procedures.

• Remove “which the certificate holder maintains in active status under the National 

Type Evaluation Program (NTEP)” as inactive certificates are still recognized.

• Replace “By maintaining the Certificate in active status, the Certificate holder 

declares the intent” with “An active Certificate represents the intent of the holder” and 

add “approved” before “type” in this sentence.

• Remove the sentence ”Some certificates may be designated as inactive.” as it is 

unnecessary.

• The definition then would appear as follows:

Certificate of Conformance (CC) – A document issued based on evaluation by an authorized 

laboratory. The document constitutes evidence of conformance of a model or models of a 

particular device, measurement system, instrument, or element that positively identifies the 

design with the requirements of this document, NIST Handbook 44, “Specifications, 

Tolerances, and Other Technical Requirements for Weighing and Measuring Devices,” and the 

relevant provisions contained in NCWM Publication 14. An active Certificate represents the 

intent of the holder to continue to manufacture or remanufacture the device consistent with the 

approved type and in conformance with the applicable requirements. A device is traceable to an 

active CC if: (a) it is of the same type identified on the Certificate, and (b) it was manufactured 

during the period that the Certificate was maintained in active status. For manufacturers of 

grain moisture meters, maintenance of active status also involves annual participation in the 

NTEP Laboratory On-going Calibration Program, OCP (Phase II). An inactive Certificate of 

Conformance is a Certificate which was previously active, but the devices are no longer being 

manufactured for commercial applications subject to local regulations or laws. However, 

devices already manufactured, installed or in inventory, but not yet sold, may be used, sold, 

repaired and resold under inactive Certificates of Conformance.

• In the definition of National Type Evaluation Program (NTEP) replace the term “operated” 

with “administered” as this is consistent with the description in Pub 14 Administrative Policy.
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Table 2. Summary of Recommendations

OTH-24.2 – Appendix D, Definitions: National Type Evaluation Program (NTEP) and Certificate of 

Conformance (CC)

Status Recommendation Note* Comments

Submitter Voting

OWM Voting With suggested edits

WWMA Developing

NEWMA Developing

SWMA Voting

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item under Consideration:

Amend Handbook 44 Appendix D, Definitions as follows:

Certificate of Conformance (CC) – A document issued based on testing by a Participating 

Laboratory, which the certificate holder maintains in active status under the National Type 

Evaluation Program (NTEP). The document constitutes evidence of conformance of a model or 

models of a particular device, measurement system, instrument, or element that positively 

identifies the design with the requirements of this document, NIST Handbook 44, 

“Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring 

Devices,” and the test procedures contained in NCWM Publication 14. By maintaining the 

Certificate in active status, the Certificate holder declares the intent to continue to manufacture 

or remanufacture the device consistent with the type and in conformance with the applicable 

requirements. A device is traceable to an active CC if: (a) it is of the same type identified on the 

Certificate, and (b) it was manufactured during the period that the Certificate was maintained 

in active status. For manufacturers of grain moisture meters, maintenance of active status also 

involves annual participation in the NTEP Laboratory On-going Calibration Program, OCP 

(Phase II). Some certificates may be designated as inactive. An inactive Certificate of 

Conformance is a Certificate which was previously active, but the devices are no longer being 
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manufactured for commercial applications subject to local regulations or laws. However, 

devices already manufactured, installed or in inventory, but not yet sold, may be used, sold, 

repaired and resold under inactive Certificates of Conformance.

National Type Evaluation Program (NTEP) – A program operated by NCWM. NTEP is a 

program of cooperation between the NCWM, NIST, other federal agencies, the states, and the 

private sector for determining, on a uniform basis, conformance of a model or models of a 

particular device, measurement system, instrument, or element that positively identifies the 

design with the relevant provisions of NIST Handbook 44, “Specifications, Tolerances, and 

Other Technical Requirements for Weighing and Measuring Devices,” and NCWM, 

Publication 14, “National Type Evaluation Program, Technical Policy, Checklists, and Test 

Procedures.”

(Added 20XX)

NIST OWM Detailed Technical Analysis: 

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, Greg VanderPlaats (Minnesota) stated that Jerry Buendel proposed 

this item because in developing tests for service agents on the national level it was discovered that those 

terms are not defined in NIST Handbook 44. Service people will have questions on these definitions. 

Recommend voting status for this item.

The Committee recommends this item as Voting.

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, comments were heard from California, Arizona, and Oregon. The 

consensus was in support for the item as it is needed. Comments were also heard suggesting simplifying 

both definitions and possibly removing the language regarding policy.

Based on the comments heard during the open hearings the WWMA S&T Committee recommends this 

item be assigned a Developing status and recommends the submitter address the comments heard during 

the open hearings.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting the committee heard no comments on this item during Open 

Hearings.

The Committee approves of defining these terms but acknowledges the language could be cleaned up 

some in regard to the differences in Active and Inactive status. Clarifying that both active and inactive 

certificates are both Certificates of Conformance. We would suggest striking “which the certificate 

holder maintains in active status” from the first sentence of the Certificate of Conformance definition.
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The Committee recommends this item move forward as a Voting item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, New York, New Jersey, and Massachusetts supported voting. 

Upon consensus of the body, the Committee recommends this item be Voting.

Item Block 1 (B1) Transfer Standard

B1-LMD-24.1 N.3.5.3. Field Standard MeterN.3.5.X. Transfer Standard Test.

B1-VTM-24.1 N.3.5.X. Field Standard Meter N.3.5.X. Transfer Standard Test.

B1-LPG-24.3 N.3.2. Field Standard MeterTransfer Standard Test.

B1-MLK-24.1 N.3.2. Field Standard Meter N.3.2. Transfer Standard Test.

B1-MFM-24.1 N.3.2. Field Standard MeterTransfer Standard Test.

Source: California Department of Food and Agriculture, Division of Measurement 

Standards

Submitter’s Purpose and Justification:

Amend NIST Handbook 44, Liquid Measuring Devices Code, Liquefied Petroleum Gas and Anhydrous 

Ammonia Liquid-Measuring Devices, Vehicle Tank Meters Code, Milk Meter Code, and Mass Flow 

Meters.

Replace the undefined term “Field Standard Meter” with the defined term “Transfer Standard”, harmonize 

the language in the paragraph with existing language in other sections regarding tests using transfer 

standards, and remove the non-retroactive status from the section.

If the term “Field Standard Meter”, which is undefined, remains in NIST HB 44 this will lead to 

confusion regarding what a “Field Standard Meter” is. This proposal is intended to remove this confusion 

by replacing this term with one that is defined in NIST HB 44. The item is a test note which would only 

apply to tests of devices moving forward, the item also identifies when it was added to NIST HB 44, 

therefore a non-retroactive status is not necessary.

The section to be amended was recently added to NIST HB 44. There may be an additional purpose 

regarding the non-retroactive status of the section.

The submitter requested Voting status for this item in 2024 as a retroactive provision.

NIST OWM Executive Summary for Item Block 1 (B1) – Transfer Standard

NIST OWM Recommendation: Voting

• OWM supports amending these items to replace the term “Field Standard Meter” with 

“Transfer Standard”, which is now a defined term in NIST Handbook 44 and amend the 

language to be consistent with similar paragraphs in other sections.
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NIST OWM Executive Summary for Item Block 1 (B1) – Transfer Standard

• Each of these Items Under Consideration in the S&T portion of Pub 15 should be edited to 

reflect the correct format prescribed by NCWM to identify changes to be made to the 

handbook as shown under the Item Under Consideration in this analysis as the intent is to 

amend these paragraphs and not replace them. 

• In addition, in the S&T portion of Pub 15, the description in the Item under Consideration for 

MFM-24.1 specifies the item will amend the “Handbook 44 Milk Meters Code”. This should 

be edited to reflect that this item is intended to amend the Mass Flow Meter Code of NIST 

Handbook 44.

Table 2. Summary of Recommendations

Item Block 1 (B1) – Transfer Standard

Status Recommendation Note* Comments

Submitter Voting

OWM Voting

WWMA Voting

NEWMA Voting

SWMA Voting

CWMA Voting

NCWM

Number of 

Support Letters

Number of 

Opposition 

Letters

Comments

Industry

Manufacturers

Retailers and 

Consumers

Trade Association

*Notes Key:

1 Submitted modified language

2 Item not discussed

3 No meeting held

4 Not submitted on agenda

5 No recommendation or not considered

Item Under Consideration:

Amend Handbook 44, Liquid Measuring Devices Code as follows:

N.3.5.3. Field Transfer Standard Meter Test. – When comparing a meter with a calibrated 

transfer standard, Tthe minimum quantity for any test draft shall be equal to or greater than the 
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amount delivered in one minute at the flow rate being tested.

[Nonretroactive as of January 1, 2024]

(Added 2023) (Amended 20XX)

B1-VTM-24.1 N.3.1. Field Transfer Standard Meter Test

Amend Handbook 44, Vehicle Tank Meters Code as follows:

N.3.1. Field Transfer Standard Meter Test. – When comparing a meter with a calibrated 

transfer standard, Tthe minimum quantity for any test draft shall be equal to or greater than the 

amount delivered in one minute at the flow rate being tested.

[Nonretroactive as of January 1, 2024]

(Added 2023) (Amended 20XX)

B1-LPG-24.3 N.3.2. Field Transfer Standard Meter Test.

Amend NIST Handbook 44, Liquefied Petroleum Gas and Anhydrous Ammonia Liquid-Measuring 

Devices Code as follows:

N.3.2. Field Transfer Standard Meter Test. – When comparing a meter with a calibrated 

transfer standard, Tthe minimum quantity for any test draft shall be equal to or greater than the 

amount delivered in one minute at the flow rate being tested.

(Added 2023) (Amended 20XX)

B1-MLK-24.1 N.3.2. Field Transfer Standard Meter Test.

Amend NIST Handbook 44, Milk Meter Code as follows:

N.3.2. Field Transfer Standard Meter Test. – When comparing a meter with a calibrated 

transfer standard, Tthe minimum quantity for any test draft shall be equal to or greater than the 

amount delivered in one minute at the flow rate being tested. 

[Nonretroactive as of January 1, 2024]

(Added 2023) (Amended 20XX)

B1-MFM-24.1 N.3.2. Field Transfer Standard Meter Test.

Amend NIST Handbook 44, Mass Flows Meters Code as follows:

N.3.2. Field Transfer Standard Meter Test. – When comparing a meter with a calibrated 

transfer standard, Tthe minimum quantity for any test draft shall be equal to or greater than the 

amount delivered in one minute at the flow rate being tested except for tests of the minimum 

measured quantity specified for the meter.

(Added 2023) (Amended 20XX)
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NIST OWM Detailed Technical Analysis: 

NIST OWM did not provide a detailed analysis for this item.

Summary of Discussions and Actions:

Regional Association Reporting:

Central Weights and Measures Association

At the 2023 CWMA Interim Meeting, no comments were heard. The Committee recommends this Block 

as Voting.

Western Weights and Measures Association

At the 2023 WWMA Annual Meeting, due to the WWMA S&T Chair Douglas being a submitter of this 

item they abstained from the Committee during Open Hearings and Committee Work Group.

Matt Douglas (California Dept. of Food and Agriculture, Div. of Measurement Standards) clarified the 

intent of this item is to replace undefined terms with defined terms recently adopted at the 2023 NCWM 

Annual Conference. Based on comments from the floor there was consensus of the item moving forward 

as a Voting item. Clarifying questions were asked with sufficient responses during open hearing. 

The WWMA S&T Committee recommends this item be assigned a Voting status. In review of this item 

and based on comments heard from the body, the Committee feels this item is fully developed, has merit, 

and meets the intended purpose of the item.

Southern Weights and Measures Association

At the 2023 SWMA Annual Meeting, the committee heard no comments on this item during Open 

Hearings. The Committee supports this item as it harmonizes the language used in these codes with 

existing language in other related sections of the handbook.

The Committee recommends this item move forward as a Voting item.

Northeastern Weights and Measures Association

At the 2023 NEWMA Interim Meeting, New Hampshire, New Jersey, and New York supports Voting 

status. Upon consensus of the body, the Committee recommends this item as Voting.

References: 

[1] NIST OWM Analysis and Executive Summary reports https://www.nist.gov/pml/weights-andmeasures/publications/owm-technical-analysis

[2] National Conference on Weights and Measures Publication 15 (2023) and 16 (2022)

https://www.ncwm.com

[3] 1905-2022 NCWM Annual Conference reports https://www.nist.gov/pml/owm/publications/ncwmannual-reports
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Appendix A. Supplemental Documents:

There are no supplemental documents within this Analysis.

Appendix B. List of Symbols, Abbreviations and Acronyms 

FHWA

Automatic Bulk Weighing System

AAR

Association of American Railroads

API

American Petroleum Institute

CNG

Compressed Natural Gas

CWMA

Central Weights and Measures Association

EPO

Examination Procedure Outline

EV

Electric Vehicle

EVFE

Electric Vehicle Fueling Equipment

EVSE

Electric Vehicle Supply Equipment

FHWA

Federal Highway Administration

HB

Handbook

LMD

Liquid Measuring Devices

LPG

Liquified Petroleum Gas

MMA

Meter Manufacturer Association

NCWM

National Conference on Weights and Measures

NEWMA

Northeastern Weights and Measures Association
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NIST

National Institute of Standards and Technology

NTEP

National Type Evaluation Program

OWM

Office of Weights and Measures

OIML

International Organization of Legal Metrology

RMFD

Retail Motor Fuel Dispenser

S&T

Specification and Tolerances

SD

Secure Digital

SI

International System of Units

SMA

Scale Manufacturers Association

SWMA

Southern Weights and Measures Association

USNWG

U.S. National Work Group

VTM

Vehicle Tank Meter

WIM

Weigh-in-Motion

WWMA

Western Weights and Measures Association