Inside this Issue

Draining Test Measures and 

Provers 1

Training and Events Calendar 2

1

Volume 6 Issue 3

March 26, 2015

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

Draining Test Measures

and Provers

Byline: G. Diane Lee

I often think about the amount of money spent on gasoline per year just to

get to and from work. Like many, I travel a considerable distance to work,

which accounts for a lot of gas and money per year. It is reassuring to know

that I can rely on the work of weights and measures officials who inspect

and test gasoline dispensers to ensure accurate measurements. Throughout

the United States, thousands of volume standards are calibrated in weights

and measures laboratories every year. Weights and measures inspectors

then use these standards to test gasoline dispensers to provide consumers

assurance that they are getting what they pay for at the pump. These tests

also protect device owners and ensure device owners are receiving fair pay‐

ment. The accuracy of these tests depends on the inspector following the

correct test procedures. One very important procedure in the testing of

gasoline dispensers is that of draining test measures and provers. Incorrectly

draining a test measure or prover can contribute a considerable amount of

error in testing. This article reviews the correct procedures for draining five‐

gallon test measures and bottom‐drain provers; answers frequently asked

questions concerning these procedures; and provides information on addi‐

tional training tools available on this topic. 

PROCEDURES FOR DRAINING TEST MEASURES AND PROVERS

NIST Handbook 44 “Specifications, Tolerances, and Other Technical Require‐

ments for Weighing and Measuring Devices” Section 3.30. Liquid Measuring

Devices, paragraphs N.4.4.1. and N.4.4.2. addresses the procedures for drain‐

ing test measures and provers.

N.4.4.1.Pour and Drain Times for Hand‐held Test Measures. –

Hand‐held test measures require a 30 second (± 5 seconds) pour fol‐

lowed by a 10 second drain with the measure held at a 10 degree to

15 degree angle from vertical.

N.4.4.2.Drain Times for Bottom Drain Test Measures or Provers. –

Bottom drain field standard provers require a 30 second drain time

after main flow cessation.

When draining a hand‐held test measure you must pour the product back

to storage by first touching the neck of the test measure to the neck of a

NATIONAL CONFERENCE

ON WEIGHTS AND MEASURES

100TH ANNUAL MEETING

JULY 19 ‐ 23 , 2015

PHILADELPHIA, PENNSYLVANIA

This milestone meeting will be taking place

in historic Philadelphia. Plan to bring your

family to tour this remarkable historical city.

Visit the Liberty Bell, Independence Hall, and

the many other historical sites in the area.

Registration and lodging information for the

July meeting is available online at:

https://www.ncwm.net/sems/event_detail/2

015_annual_pa. 

The meeting schedule, supporting docu‐

ments, and hotel information are also avail‐

able at this website location.

Let Your Voice Be Heard!
W&M Connection 2 Volume 6 Issue 3

Training and Events

Calendar 

2015

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 1 (2 hr)

Webinar ‐ NISTIR 6969, SOP 8, Part 1

2:00 p.m. ‐ 4:00 p.m.

Class No. 5364

April 2 (2 hr)

Webinar ‐ NISTIR 6969, SOP 8, Part 2

2:00 p.m. ‐ 4:00 p.m.

Class No. 5365

April 8 (2 hr)

Webinar ‐ NISTIR 7383, SOP 19 (18) Part 1

2:00 p.m. ‐ 4:00 p.m.

Class No. 5366

April 9 (2 hr)

Webinar ‐ NISTIR 7383, SOP 19 (18)

Part 2

2:00 p.m. ‐ 4:00 p.m.

Class No. 5367

April 13 ‐ 17 (5 days)

Handbook 133, “Checking the Net Contents

of Packaged Goods,” Basic

Class No. 5362

Indianapolis, IN (continued pg 3)

metal funnel. A plastic funnel may cause a static electric charge, and must

not be used to return product back to storage. The contents must be poured

slow enough so that the main flow stops after 30 seconds ± 5 seconds. Then,

the remaining liquid is drained for 10 seconds at a 10 degree to 15 degree

angle from vertical.

When draining a five‐gallon truck mounted prover, the truck is typically

grounded to the dispenser before testing begins. Some jurisdictions also

ground the prover to the storage tank on the truck. You should check with

your organization’s safety officer or other expert to ensure that equipment

is properly grounded. The release valve on the prover is opened and the

product is drained from the prover to the storage tank below. Observe the

sight glass as the liquid drains from the prover. After the main flow stops,

the remaining liquid is allowed to drain for 30 seconds and the valve is closed.

Although these procedures may not seem difficult to a more seasoned in‐

spector, no matter what your experience level, the following frequently asked

questions may provide new information or confirm or enhance your existing

knowledge of draining test measures and provers. 

Frequently Asked Questions:

What is a test measure? What is a prover?

Both a test measure and prover are volumetric standards used to test gasoline

dispensers and other liquid measuring devices. Requirements for these field

standards are included in NIST 105‐3, “ Specifications and Tolerances for Grad‐

uated Neck‐Type Volumetric Field Standards.“ 

“Test measures” are small, hand‐held volumetric measures that are typically

20 L (5 gal) or smaller in size. See Figure 1 ‐ Test Measure.

“Provers” are bottom‐drain volumetric measures and may be free standing

or permanently mounted on a truck, platform, or trailer that are typically 20 L

(5 gal) or larger. See Figure 2 ‐ Prover.

Figure 2 ‐ Prover

LEGEND

1‐Removable Cap

2‐Vapor Return

3‐Neck Reinforcement

4‐Gauge Mounting

5‐Gauge Assembly

6‐Bullseye Level

7‐Thermometer Well

8‐Identification Plate

9‐Reinforcing Bands

10‐Vortex Breaker

11‐Drain Valve

12‐Sight Glass

13‐Swivel Ball Joint As‐

sembly

14‐Truck Storage/Transfer

Tank

1

3 2

4

5

6

7

8

9

10

11

12

13

14

LEGEND

1‐Neck Reinforcement

2‐Handle (raised)

3‐Gauge Assembly

4‐Gauge Mounting

5‐Reinforcing Bands

6‐Identification Plate

7‐Concave Bottom

Figure 1 – Test Measure
W&M Connection 3 Volume 6 Issue 3

The Office of Weights and Measures

will glady include your weights and measures related events in

our calendar.

Contact the Editor: Linda.Crown@nist.gov

April 13 ‐ 16 (4 days)

SEMAP**

Class No. 5357

Tallahassee, FL

April 14 ‐ 16 (3 days)

Train the Trainer

Class No. 5353

NIST/Gaithersburg, MD

April 20 ‐ May 1 (10 days)

Mass Metrology Seminar

Class No. 5374

NIST/Gaithersburg, MD

May 4 ‐ 7 (4 days)

WRAP**

Class No. 5358

Olympia, WA

May 4 ‐ 8 (5 days)

Northeast Weights and Measures Associa‐

tion (NEWMA) Annual Meeting

Saratoga Springs, NY

Contact: James Cassidy, 

jcassidy@cambridgema.gov

May 12 ‐ 13 (2 days)

Multiple Dimension Measuring Device Work

Group Meeting

Reyoldsburg, OH

Information at: 

https://www.ncwm.net/meetings/ntep/md

md

May 18 ‐ 22 (5 days)

Central Weights and Measures Association

(CWMA) Annual Meeting

Columbus, OH

Contact: Sherry Turvey, 

sherry.turvey@kda.ks.gov

June 1 ‐ 5 (5 days)

Handbook 133, “Checking the Net Contents

of Packaged Goods,” Basic

Class No. 5345

Indianapolis, IN

June 1 ‐ 5 (5 days)

Liquefied Petroleum Gas Liquid‐Measuring

Devices

Class No. 5375

Madison, WI

June 1 ‐ 11 (9 days)

Advanced Mass Seminar (Rev 2015)

Class No. 5349

NIST/Gaithersburg, MD

July 19 ‐ 23 (5 days)

National Conference on Weights and Meas‐

ures (NCWM) Annual Meeting

Philadelpha, PA

Contact: info@ncwm.net

July 19 ‐ 23 (5 days)

NCSL International Conference 2015

Metrology and the Quality of Life

Grapevine, TX

Information: www.ncsli.org

(continued pg 4)

Why is it important to follow proper drain procedures?

When liquid is drained from a test measure or prover, a residual amount of

liquid will remain clinging to the walls. It is impractical to dry the inside of the

test standard between uses; thus, when a standard is calibrated, it is cali‐

brated “to deliver” its content. A “to deliver” calibration means that the

standard is calibrated to compensate for this clingage so that tests can be run

one after another without having to take time out to thoroughly dry the stan‐

dard before each test. Using proper drain procedures ensures that each time

you perform an accuracy test on a gasoline dispenser, you start with the same

amount of liquid clinging to the inside of the standard between each test and

helps to ensure accurate measurements from test to test. 

If the inside of a standard is dry, the standard must be wet down (e.g. fill the

standard to capacity and follow the draining procedures in this article) before

using it to test gasoline dispensers. During periods of non‐use, such as, driv‐

ing from one location to another location for testing or breaking for lunch

while testing at one location, care must be taken to ensure that testing re‐

sumes with a standard that has been properly wet down. 

When draining a test measure, how do I hold the test measure at a 10 to

15 degree angle? 

One way to determine if you are holding the test measure at a 10 degree to

15 degree angle from vertical when draining it is to think of the arm that you

use to hold the handle of the test measure as your vertical line (a line that

extends up and down) (See Figure 3). This arm makes a 90 degree angle with

the ground (See figure 3 and 4). Holding the bottom of the test measure with

your other hand, adjust the test measure to the 10 degree to 15 degree angle

from vertical as shown in Figures 3 and 5.

Figure 3 – Inspector Draining a Test Measure at a 10 Degree to 15 Degree Angle.
W&M Connection 4 Volume 6 Issue 3

August 10 ‐ 14 (5 days)

Fundamentals of Metrology

Class No. 5373

NIST/Gaithersburg, MD

August 13 (2 hr)

Webinar ‐ Contract Review

2:00 p.m. ‐ 4:00 p.m.

Class No. 5334

August 17 ‐21 (5 days)

Volume Metrology Seminar

Class No. 5356

NIST/Gaithersburg, MD

August 19 ‐ 20 (2 days)

NTEP Grain Analyzer Sector Meeting

Live Web Meeting

Details unavailable at this time.

Information to be posted at:

https://www.ncwm.net/ntep/sectors/grain‐

analyzer/registration

August 25 ‐ 26 (2 days)

Weighing Sector Meeting

Denver, CO

Information at: 

http://www.ncwm.net/sems/event_detail/201

5_weighing

August 27 (2 hr)

Webinar ‐ Document Control and Record

Keeping

2:00 p.m. ‐ 4:00 p.m.

Class No. 5335

September 14 ‐ 17 (4 days)

NEMAP**

Class No. 5359

Needham, MA

September 15 ‐ 16 (2 days)

NTEP Measuring Sector Meeting

Denver, CO

Information at:

http://www.ncwm.net/meetings/ntep/mea

suring (continued pg 5)

How do I correctly measure the drain times for test measures and provers?

When draining test measures or provers, inspectors must use a stop watch

or other timing device with a second indicator to determine the correct drain

time. 

Test measures must be emptied by pouring the contents slowly enough that

the main flow stops after 30 seconds and then drained for 10 seconds at a

10 degree to 15 degree angle. While it may be difficult to look at a stop watch

or watch with a second hand or digital indicator while pouring the contents

of the test measure, an option is to wear the stop watch around the neck and

periodically look down at the stopwatch to determine if you need to adjust

the timing of your pour. A watch with a second hand or indicator worn on

the arm used to hold the handle of the test measure could also be used. Turn

the watch so that you can see the second hand or indicator as you pour and

then drain liquid from the test measure. 

On a bottom‐drain prover, open the drain valve with one hand and hold the

timing device in the other hand. After the main flow stops, begin timing

the drain for 30 seconds. See Figure 6 ‐ Inspector draining a prover. 

Vertical Line

10°

15°

Figure 4 – Draining at a 10 Degree to 15 Degree Angle

Figure 5 – Test Measure at

a 10 Degree Angle

Figure 6 – Inspector Draining a Prover
WEIGHTS AND MEAS‐ URES

IN THE NEWS

Eyewitness News 3 (WFSB.com)

Experts show how to get the proper

weight of favorite items

http://www.wfsb.com/story/28274453/ex‐

perts‐show‐how‐to‐get‐the‐proper‐weight‐

of‐favorite‐items

Sandusky Register

Balancing the scales

http://www.sanduskyregister.com/new

s/government/7720076

Commerce.Gov

Weights and Measures Week 2015:

On the Path to Tomorow

http://www.commerce.gov/blog/2015/03/

04/weights‐and‐measures‐week‐2015‐

path‐tomorrow

ABC News 7

Consumer Alert: The olive oil you buy

may be a rip‐off

http://www.wjla.com/articles/2015/03/con

sumer‐alert‐the‐olive‐oil‐you‐buy‐may‐be‐a‐

rip‐off‐111994.html

W&M Connection 5 Volume 6 Issue 3

September 16 ‐ 17 (2 days)

NTEP Software Sector Meeting

Denver, CO

Information at:

http://www.ncwm.net/meetings/ntep/software

September 24 (2 hr) (tentative)

Webinar ‐ State Laboratory Annual Submission Process**

2:00 p.m. ‐ 4:00 p.m.

Class No. 5355

September 27 ‐ October 1 (5 days)

Western Weights and Measures Association (WWMA) Annual Meeting

Boise, ID

Contact: Jerry Buendel, 

jbuendel@agr.wa.gov

September 28 ‐ October 1 (4 days)

SWAP**

Class No. 5360

Columbia or Jefferson City, MO

October 5 ‐ 7

Central Weights and Measures Association (CWMA) Interim Meeting

St. Charles, MO

Contact: Sherry Turvey,

sherry.turvey@kda.ks.gov

October 5 ‐ 8 (4 days)

MidMAP**

Class No. 5361

Madison, WI

October 19 ‐ 23 (5 days) (tentative)

CaMAP**

Class No. 5372

San Juan, PR

October 22 (2 hr)

Webinar ‐ Internal Auditing Best Practices

2:00 p.m. ‐ 4:00 p.m.

Class No. 5339

October 26 ‐ November 6 (2 weeks) (tentative)

Mass Metrology Seminar

Class No. 5340

NIST/Gaithersburg, MD

2016

January 9 ‐ 14

National Conference on Weights and Meas‐

ures (NCWM) Interim Meeting

San Diego, CA

Information at: 

http://www.ncwm.net/sems/event_detail/2

016‐interim‐meeting

February 11 (2 hr) (tentative)

Webinar ‐ Conducting an Effective Management

Review

2:00 p.m. ‐ 4:00 p.m.

Class No. 5336

March 3 (2 hr)

Webinar ‐ Internal Auditing Best Practices

2:00 p.m. ‐ 4:00 p.m.

Class No. 5337

*Invitation Only

**Limited to State Laboratory Program Par‐

ticipants

Training Tools 

The NIST, Office of Weights and Measures (OWM) provides other training

tools on draining test measures and provers. You may visit the weights and

measures contacts system at https://tsapps.nist.gov/WMD/default.aspx to

locate webinars being provided on this topic. Additionally, a retail motor fuel

dispenser inspection video and shorter videos including this topic are avail‐

able on our website at http://www.nist.gov/pml/wmd/. 

Incorrectly draining a test measure or prover can contribute a considerable

amount of error in testing. Following the test procedures in this article will

help to ensure that accurate test results are obtained when testing gasoline

dispensers and help to ensure accurate commercial measurement transac‐

tions.

For additional information on draining test measures and provers, contact

Diane Lee at (301) 975‐4405.