Inside this Issue

Measurement and Marketing: Considera‐

tions When Determining the Method 

of Sale for Liquefied Natural Gas (LNG) 

and Compressed Natural Gas (CNG)

1

Training and Events Calendar 2

Important Update:

FTC’s Fair Packaging and Labeling Act 4

Publications:

OWM Publications Update 5

1

Volume 7 Issue 2

March 24, 2016

OFFICE OF WEIGHTS AND

MEASURES

General Inquries: (301) 975‐4004; e‐mail:

owm@nist.gov

Office Chief, Carol Hockert: e‐mail:

carol.hockert@nist.gov

Newsletter Editor: Linda Crown; (301) 975‐

3998; e‐mail: linda.crown@nist.gov

CHECK OUT THE NEW

CLASSES ADDED TO THE

TRAINING AND EVENTS

CALENDAR FOR 2016.

Measurement and Marketing: 

Considerations When De‐

termining the Method of

Sale for Liquefied Natural

Gas (LNG) and Compressed

Natural Gas (CNG)

Byline: Juana Williams

This article was developed by National Institute of Standards and Technology

(NIST), Office of Weights and Measures (OWM) and originally titled “Mea‐

surement and Marketing: Considerations when Determining the Method of

Sale (MOS) for Liquefied Natural Gas (LNG)/Compressed Natural Gas (CNG).”

This discussion was first published as a companion piece to industry’s view‐

point on a proposal to modify NIST Handbook legal metrology requirements

for commercial vehicle fueling equipment and the MOS for CNG and LNG.

Both perspectives appeared in the article “Weighing In: Two different organ‐

izations offer their stance on how to measure CNG and LNG” published in

the spring 2015 edition of The Source: The Voice and Choice of Public Gas,

Vol. 7, Issue 3, pp. 10 – 13, which is also available at: http://www.nxtbook.com/nay‐

lor/PGAQ/PGAQ0115/index.php#/12. 

The following information, based on the NIST OWM piece published in The

Source: (1) addresses an issue currently being considered by the U.S.

weights and measures community and natural gas industry; and (2) is being

reprinted to provide the legal metrology community with fundamental

philosophies that are used along with technical principles for good meas‐

urement practices to establish a uniform and traceable MOS for sale of com‐

modities by weight, measure, or count. 

The basic principles of measurement used in trade and commerce date back

thousands of years and must be understood by everyone, buyers and sellers,

businesses and consumers. To put it simply, measurements in commerce

must be clear, transparent, verifiable, and understandable to protect con‐

sumers and ensure fair competition among businesses. In the United States,

our forefathers understood the importance of good measurement in com‐

merce; John Quincy Adams wrote, “Weights and Measures may be ranked

among the necessaries of life...and is often learned by those who learn noth‐

ing else, not even to read and write.” To that end, Congress has passed var‐

ious legislations associated with ensuring uniform measurements in the

marketplace, including the creation of the Office of Weights and Measures

in 1836 and the signing of the Treaty of the Meter in 1875. With the found‐

The Office of Weights

and Measures

will glady include your weights and

measures related events in our cal‐

endar.

Contact the Editor:

Linda.Crown@nist.gov
W&M Connection 2 Volume 7 Issue 2

Training and Events

Calendar 

2016

Registration for training in the NIST Office of

Weights and Measures is handled by Yvonne

Branden at yvonne.branden@nist.gov.

Course descriptions can be viewed on the Of‐

fice of Weights and Measures website at

http://www.nist.gov/pml/wmd/calendar.cfm

and clicking on the name of the course. 

April 4 ‐ 8 (5 days)

Fundamentals of Metrology

Class No. 5380

NIST/Gaithersburg, MD

April 5 ‐ 7

NTEP Lab Meeting

Columbus, OH

www.ncwm.net

April 7 (2 hr)

Webinar ‐ Software Verification and Validation

2:00 p.m. ‐ 4:00 p.m.

Class No. 5399

April 4 ‐ 7 (4 days)

Handbook 133, Checking the Net Contents of Pack‐

aged Goods ‐ Basic

Class No. 5411

Sparks, NV

April 8 (1 day)

Handbook 130, Uniform Packaging and Labeling

Regulations, Price Verification

Class No. 5412

Sparks, NV

April 11 ‐ 14 (4 days)

SEMAP**

Class No. 5405

Richmond, VA

April 18 ‐ 21 (4 days)

CaMAP**

Class No. 5406

Bayamon, PR

April 26 ‐ 27 (2 days)

NTEP MDMD Work Group Meeting

Reynoldsburg, OH

www.ncwm.net

April 27 (2 hr)

Webinar ‐ Calibration Method Validation

2:00 p.m. ‐ 4 p.m. 

Class No. 5430

April 28 (2 hr)

Webinar ‐ Calibration Method Validation

2:00 p.m. ‐ 4:00 p.m.

Class No. 5400

(continued on pg 3)

ing of the National Conference on Weights and Measures by the National Bu‐

reau of Standards in 1905, the United States took a significant step towards

assuring uniformity and equity in commerce throughout the states. 

Establishing an acceptable method of sale is a critical first step in the devel‐

opment of a fair and competitive marketplace for any commodity. For in‐

stance, milk could be sold by volume, or it could be sold by mass. If both

were allowed, the measurement principles cited above would be violated.

That is, a volume of milk purchased at one location could not easily be com‐

pared by a consumer against a weight of milk purchased elsewhere and, thus,

frustrate value comparison. For this reason, milk is only allowed to be sold

by volume in retail stores. History has shown that when products are intro‐

duced into the marketplace without a legally defined standard, confusion and

unfair competitive practices can quickly evolve and potentially harm the con‐

sumer’s perception of the product and business reputation of the seller. For

example, at one time, precious metals were being sold by the troy ounce as

well as the avoirdupois ounce. Unscrupulous dealers would buy gold by one

unit and sell by another, taking advantage of unaware customers. 

When faced with deciding on the best method to advertise and sell a new

commodity, existing trade practices are reviewed to determine what already

works and what can be improved. This review should include a look at what

occurs globally. Another consideration is how the product is measured at the

time of sale. Perhaps most importantly, and in keeping with the Treaty of the

Meter, measurements made in commerce must be traceable to the Interna‐

tional System of Units (SI). The requirement of traceability allows for inter‐

state and international commerce, and provides assurance that a

measurement made at one location is comparable to a measurement made

across the country or around the world. In looking at the method of sale for

gasoline, historically it has been sold by volume. It is sold by volume around

the world, and it is measured and dispensed by volume. NIST has the respon‐

sibility for fixing standards for measurement. As an example, it can be shown

that the unit of volume used in the United States, the gallon, is traceable to

the SI: One gallon is defined in NIST Handbook 44, “Specifications, Tolerances,

and Other Technical Requirements for Weighing and Measuring Devices,” as

exactly 231 cu in and an inch is defined as exactly 0.0254 m, with the cubic

meter being the SI unit of volume. Because the SI, the modern metric system

of measurement, is becoming the dominant measurement system used in in‐

ternational commerce, NIST Special Publication (SP) 811, “Guide for the Use

of the International System of Units (SI),” and NIST SP 330, “The International

System of Units (SI),” are the legal interpretations of and guidelines for the

use of SI in the United States. NIST definitions of measurement units can be

supported and verified throughout each level in the hierarchy for traceable

measurements. 

Although it is a more complicated measurement, the same logic can be ap‐

plied to the sale of natural gas as a vehicle fuel (Compressed Natural Gas

[CNG] or Liquefied Natural Gas [LNG]). Globally, with the exception of the

United States, the product is sold by mass (kilogram). This is largely because

natural gas dispensed as vehicle fuel is, for the most part, measured and dis‐

pensed by mass. In the United States, the product is also measured and dis‐

pensed by mass, and the measurement is verified in pounds; however, this

vehicle fuel is sold in fuel equivalent units (gasoline gallon equivalent [GGE]

or diesel gallon equivalent [DGE]). 

It has been suggested that the most appropriate method of sale of these fuels

would be by their energy content. This would be analogous to a home

owner’s purchase of natural gas heating fuel metered by a temperature com‐

pensated vapor meter. The owner is billed on the metered usage that is con‐
W&M Connection 3 Volume 7 Issue 2

May 2 ‐ 5 (4 days)

WRAP**

Class No. 5407

Los Angeles, CA

May 16 ‐ 19 (4 days)

NEWMA Annual Meeting

Portland, ME

www.ncwm.net

May 16 ‐ 27 (10 days)

Mass Metrology Seminar

Class No. 5381

NIST/Gaithersburg, MD

May 23 ‐ 26 (4 days)

CWMA Annual Meeting

Rapid City, SD

www.ncwm.net

May 23 ‐ 26 (4 days)

Retail Motor‐Fuel Dispensers and Consoles

Class No. 5404

Rapid City, SD

June 6 ‐ 10 (5 days)

Laboratory Administration Seminar

Class No. 5382

NIST/Gaithersburg, MD

June 13 ‐ 17 (5 days)

Volume Metrology Seminar

Class No. 5398

NIST/Gaithersburg, MD

June 13 ‐ 17 (5 days)

Liquefied Petroleum Gas (LPG)

Liquid‐Measuring Systems

Class No. 5419

Raleigh, NC

July 24 ‐ 28 (5 days)

National Conference on Weights and Mesaures

101stAnnual Meeting

Denver, CO

info@ncwm.net

August 8 ‐ 12 (5 days)

Fundamentals of Metrology

Class No. 5417

NIST/Gaithersburg, MD

August 11 (2 hr)

Webinar ‐ Contract Review

2:00 p.m. ‐ 4:00 p.m.

Class No. 5383

August 22 ‐ 26 (5 days)

Handbook 133 ‐ Chapter 4, Dimensional Measure‐

ment

Class No. 5401

NIST/Gaithersburg, MD

August 23 ‐ 24 (2 days)

NTEP Weighing Sector Meeting

Denver, CO

www.ncwm.net

August 25 (2 hr)

Webinar ‐ Document Control and Recordkeeping

2:00 p.m. ‐ 4:00 p.m.

Class No. 5384

(continued on pg 4)

verted to its value in therms (a heat value equal to 100 000 Btu [1.05 x 102

MJ] at a specified temperature ). However, vehicle fueling occurs over a short

period of time and the energy content of the fuel depends on the fuel’s con‐

stituents, source, the season, reservoir of product in storage, etc. How much

energy the vehicle can glean from a tank of fuel will depend on the engine’s

efficiency, vehicle load, terrain, environment, and a host of other factors. So,

in 1994 both industry and the weights and measures community agreed that

attempting to establish and maintain a precise conversion between the actual

energy content of gasoline and natural gas and to maintain and verify the re‐

lationship was considered to be an unrealistic task at the retail level.

Over the course of an actual fuel delivery an automatic means should be in

place to correct for energy content fluctuation which contributes to the vari‐

ation in energy equivalent content for a fuel product. Unfortunately, to indi‐

cate an averaged or estimated energy equivalent unit on the fuel dispenser’s

total quantity display breaks the hierarchy of traceability, which is necessary

for rigorous and credible measurements. An equivalent unit based on an es‐

timated energy content does not provide the consumer with the measured

quantity of product being dispensed, violating the basic principles of meas‐

urement in trade and commerce. 

As a result, the natural gas market is faced with competing desires between

sound trade practices and the ability to market natural gas in terms to which

consumers can relate. One potential solution could be to allow for the sale

of natural gas by mass (as it is dispensed and measured) and to recognize its

marketing by the fuel gallon equivalent (for comparison shopping). Supple‐

mentary information such as this is used to market a variety of products, such

as laundry detergent (approximate number of wash loads) or shredded

cheese (approximate number of cups); however, this “comparison” informa‐

tion is not used as the basis for sales.

It has been more than two decades since the community’s move to recognize

a conversion value that resulted in the creation of a supplemental fuel “unit”

of measurement. The supplemental unit is in use for CNG fuel advertisement

and part of the equation used to calculate the sales transaction. If the com‐

munity moves in that same direction to create yet another supplemental nat‐

ural gas vehicle fuel unit, then the community is encouraged to use and

document recognized scientific methods for establishing such a conversion

factor. The 20 year old MOS practice for CNG continues to convert based on

a fixed conversion factor that was derived using the lowest estimated energy

content value for a specific type of fuel; while acknowledging that the energy

content for a supply of fossil fuel even when it meets a fuel quality standard

is in a constant state of fluctuation.

In 1993, studies were conducted using averaged energy data to compare one

fossil fuel to another, that is, the mean natural gas composition based on the

Wobbe number and the lower heating value for gasoline (i.e., “indolene”), to

arrive at a list of possible conversion factors. The factor the community chose

would be applied to the mass metered by the CNG dispenser and converted

to the gasoline gallon equivalent (GGE) value of CNG for use in the quantity

display and then the GGEs would be used to calculate the total dollar value

for each sale. This practice may not take into account the effect that varia‐

tions in thermophysical and other properties of the fuel have in the determi‐

nation of commercial measurement results. Alternative fuels offer safe clean,

domestic sources of energy for the United States. It is anticipated that the

community will receive future requests for ways to make comparisons be‐

tween other or newer alternative fuels. Therefore, It becomes necessary to

utilize the most current technology and data to provide supplemental com‐

parison information in a uniform and fair manner. This will to avoid confusion
W&M Connection 4 Volume 7 Issue 2

September 11 ‐ 15 (5 days)

WWMA Annual Meeting

Honolulu, HI

www.ncwm.net

September 13 ‐ 14 (2 days)

NTEP Grain Analyzer Sector Meeting

Kansas City, MO

www.ncwm.net

September 14 (1 day)

NTEP Measuring Sector Meeting

Kansas City, MO

www.ncwm.net

September 19 ‐ 22 (4 days)

NEMAP**

Class No. 5408

Concord, NH

October 3 ‐ 6 (4 days)

SWAP**

Class No. 5409

Austin, TX

October 17 ‐ 20 (4 days)

MidMAP**

Class No. 5410

Columbus, OH

October 20 (2 hr)

Webinar ‐ Internal Auditing Best Practices

2:00 p.m. ‐ 4:00 p.m.

Class No. 5385

September 20 ‐ 21 (2 days)

NTEP Measuring Sector Meeting

Denver, CO

www.ncwm.net

October 24 ‐ November 4 (10 days)

Mass Metrology Seminar

Class No. 5386

NIST/Gaithersburg, MD

2017

February 16 (2 hr)

Webinar ‐ Conducting an Effective Management

Review

2:00 p.m. ‐ 4:00 p.m.

Class No. 5416

March 2 (2 hr)

Webinar ‐ Internal Auditing Best Practices

2:00 p.m. ‐ 4:00 p.m.

Class No. 5420

*State W&M labs only or invitation only.

**Regional Measurement Assurance Pro‐

gram “MEMBERS” (State and Industry RMAP

member laboratories.)

and giving an unfair advantage to any one fuel sector. The community should

be able to point to rigorous methodology that can clearly and repeatedly be

used to arrive at each conversion factor. The use of a supplemental fuel equiv‐

alent unit should be studied to determine the impact of reporting quantities

to other agencies to avoid confusion or the creation of trade barriers because

of erroneous use of the term or expanding its use into other disciplines where

similar principles do not apply. 

As noted above, there is one option the community discussed in 2014 that of‐

fered some flexibility, where natural gas vehicle fuel sales are conducted on

the basis of mass in a traceable unit of measurement but which also recog‐

nized use of separate supplemental fuel comparison information or the fuel

gallon equivalent (strictly for comparison shopping). In this option, a fixed

conversion factor would be recognized and used throughout the United States.

To permit other than a fixed factor would require monitoring by the authorities

to eliminate instances of exaggerated claims about a variable fuel supply’s

(seasonal, comingled storage, etc.) energy content. In February 2015, a new

work group was formed that includes members from the weights and meas‐

ures and natural gas communities to review the scientific data and other back‐

ground materials cited in support of the newly proposed values for the

conversion of mass measurements of natural gas vehicle fuels to approximate

diesel gallon equivalent units. The work group at the time of publication of

this article had not yet reached a consensus on the data used to arrive at the

proposed conversion factors. NIST OWM encourages the use of reliable and

approved measurement technology that can be supported (i.e., measurements

calibrated and traceable back to SI units) by the legal metrology infrastructure.

In July 2015, the U.S. standards development process returned a proposal to

recognize a second fuel “equivalent unit” for the second time. The standards

development process allows for further consideration of that proposal (or an

alternative) by the NCWM Specifications and Tolerances Committee (for device

requirements) and the NCWM Laws and Regulations Committee (for MOS re‐

quirements). NIST OWM encourages the community to revisit alternative MOS

proposals intended as a compromise that would ensure traceability of the

units of measurement at the time of fuel delivery while offering supplemental

information that allows for fuel comparisons.

Important Update

NIST HANDBOOK 133 CONVERSION TA‐ BLES INCORPORATED INTO FTC’S FAIR

PACKAGING AND LABELING ACT

The Federal Trade Commission issued final amendments to its rules and reg‐

ulations promulgated under the Fair Packaging and Labeling Act (FPLA), which

included the incorporation of comprehensive metric conversion tables in NIST

Handbook 133 “Checking the Net Contents of Packaged Goods.” The amend‐

ments also modernize the place of‐business listing requirement, clarify guid‐

ance on the use of exponents with customary inch/pound measurements,

and eliminate outdated regulations on retail price sales related to “cents‐off”

representations, introductory offers, and economy size packages. One signif‐
W&M Connection 5 Volume 7 Issue 2

OWM Publication Updates*

Georgia L. Harris, Program Leader

NISTIR 6969, Selected Laboratory and Measurement Practices, and Procedures to Support Basic Mass Calibrations

Several procedures have been updated in NISTIR 6969 and are posted on the OWM Calibration Procedures website

(http://www.nist.gov/pml/wmd/labmetrology/calibration.cfm). The “Revision Control” document posted with the publication provides a

highlight of the changes that were made to the following documents:

• GLP 9, Rounding Expanded Uncertainties and Calibration Values

• GMP 11, Assignment and Adjustment of Calibration Intervals for Laboratory Standards

• SOP 2, Applying Air Buoyancy Corrections

• SOP 33, Calibration of Weights Carts

• SOP 34, Selection and Use of Sensitivity Weights and Tare Weights in Weighing Procedures

NISTIR 7383, Selected Procedures for Volumetric Calibrations

Several procedures have been updated in NISTIR 7383 and are posted on the OWM Calibration Procedures website

(http://www.nist.gov/pml/wmd/labmetrology/calibration.cfm). Again, the “Revision Control” document posted with the publication provides

a highlight of the changes that were made to the following documents:

• SOP 14, Gravimetric Calibration of Volumetric Ware Using an Electronic Balance

• SOP 18, Calibration of Graduated Neck‐Type Metal Volumetric Field Standards, Volumetric Transfer Method

• SOP 19, Calibration of Large Neck‐Type Metal Provers, Volume Transfer Method

• SOP 21, Calibration of LPG Provers

• SOP 26, Gravimetric Calibration of Dynamic Volumetric Systems used as Standards

The primary reasons for changes were to add options for rounding practices to GLP 9. A few changes were made to SOPs

14, 18, 19, 21, 26, and 33 to note that the mean calibration value from replicate runs should be used when reporting mass

and volume results and to note which values should be tracked on standard deviation charts if/when there are adjustments.

SOP 2 was changed to add a formula from SOP 28 for calculating effective density. GMP 11 changes included an addition

of 100 g starting restraints and check standards to the Mass Echelon I table and to change the calibration intervals for liquid

in glass thermometers used as reference standards. The calibration interval for liquid in glass thermometers was changed

in response to a complaint that was submitted with additional supporting references regarding the stability of that type of

thermometer. SOP 34 was changed based on confusion about selecting tare weights and sensitivity weights that was ob‐

served in the last Mass Metrology Seminar. 

There was a web presentation on February 25, 2016, that provided a detailed overview of the changes made to these pro‐

cedures. If you missed the session and want to review a recording of it, please contact Georgia Harris at gharris@nist.gov

Publications

icant addition is a section that notifies packagers that while some goods are exempt from FTC regulation, they nonetheless

still fall under the purview of the individual state weights and measures laws. A majority of the revisions made by FTC to

the FPLA were requested by the National Conference on Weights and Measures, where NIST staff serve as technical advisors. 

Point‐of‐Contact: Laws and Metric Group (301) 975‐4004.
W&M Connection 6 Volume 7 Issue 2

for the link and password. 

NIST Handbook 105‐4, Specifications and Tolerances for Liquefied Petroleum Gas and Anhydrous Ammonia Liquid Volu‐

metric Provers (2010)

A concern was raised within the Office of Weights and Measures (OWM) regarding Section 4.10 and the use of bleed lines

in NIST Handbook 105‐4. Note that this section was added in the 2010 version of Handbook 105‐4 but did not exist in the

1997 version. There has been a request by the Legal Metrology Devices Program to remove Section 4.10. The use of bleed

valves facilitates testing and enables inspectors to more quickly establish a zero condition during meter evaluations. Addi‐

tionally, the procedures used in Canada that were updated in October 2015 also reference the use of bleeder valves to

adjust the volume during the meter tests. Limited comments were submitted during the reviews between 1997 and 2010

that resulted in adding this requirement, but the comments did not provide legal requirements or a basis for not allowing

bleed lines. However, there were also no comments opposing the addition of Section 4.10 during the final draft reviews.

The OWM Laboratory Metrology Program has no metrological basis for retaining this section. Therefore, it is the proposal

from the NIST Office of Weights and Measures to remove this requirement from the handbook (section 4.10, page 14),

pending input and justification from users of this document. 

You can review a posted draft of Handbook 105‐4 (2016), a memorandum that identifies the issue in more detail, and

submit comments via the OWM Contact System (https://tsapps.nist.gov/WMD/default.aspx). After logging in, follow these

steps:

• Select My Comments from the menu bar (4th item in from the left).

• Select “Submit” a Comment radio button that is above any lists of comments you may have previously entered. 

• Select “Handbook 105‐4 (2016)” from the list. 

• Enter your Section, Page, and Comment.

• Press Continue.

• Review your submission and press Edit or Submit.

Action Items:

Be sure to review the latest procedures and revision control document, update your Quality Management System

master file (if these measurements are on your laboratory Scope), and implement them into your normal opera‐

tions. 

Review the latest draft of NIST Handbook 105‐4 and memorandum, and submit your comments on the document. 

*Note: Good Laboratory Practices (GLPs)

Good Measurement Practices (GMPs)

Standard Operating Procedures (SOPs)

NATIONAL CONFERENCE ON WEIGHTS AND

MEASURES

101TH ANNUAL MEETING

JULY 24 ‐ 28, 2016

DENVER, COLORADO

Registration and lodging information for the July meeting is available online at:

https://www.ncwm.net/sems/event_detail/2016‐annual‐co. 

The meeting schedule, and supporting documents are also available at this website location.