NIST OWM Study Guide-GMM/NIR Devices Page 1 of 8 Rev 04/17/20

NIST, Office of Weights and Measures

Study Guide

for

Grain Moisture Meters (GMMs) and

Near Infrared (NIR) Measuring Devices

NIST OWM Study Guides are designed for use by weights and measures officials and service personnel 

to enhance and strengthen their knowledge of specific areas of legal metrology inspection and testing. 

These study guides are not intended to be a comprehensive summary of all training and development 

opportunities recommended for inspectors working in a specific topic area. Rather, they are intended 

to help individuals in their professional development by targeting the use of information and resources 

available on the NIST OWM website. Study guides are particularly ideal for use by individuals who are 

working remotely and are striving to enhance and strengthen their technical knowledge.

Included in this study guide are:

• An overview of resources available on the NIST OWM website, including self-study course 

material; videos; and newsletter articles and guidance documents on legal metrology issues.

• Suggestions for how each of these resources might be used for either independent, 

individual study or by groups of inspectors/service personnel led by an instructor or 

supervisor.

• Information on other training opportunities, including both on-line training and in-person 

instructor-led training and other resources for professional development.

We hope you find this guide useful in your continued development as a legal metrology professional. 

Please contact NIST OWM at owm@nist.gov if you have questions about this guide or suggestions 

for its improvement.

I. Course Materials – Self-Study Course on NIST Handbook 44

Estimated Study Time: 8-16 hours (self-study time; see below for details)

Below is a NIST OWM website link to a NIST Handbook 44 course designed for use as a selfstudy activity. OWM recommends completing this course before proceeding to other 

resources.

This self-study course describes the history, organization, and intended use of NIST Handbook 

44. It also provides instruction on NIST Handbook 44 terminology; how to locate specific 

paragraphs; use of the National Conference on Weights and Measures Final reports to 

understand the application of specific sections; and use of requirements in conjunction with 

the NIST Examination Procedure Outlines.
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https://www.nist.gov/pml/weights-and-measures/legal-metrologydevices/training-materials

While this course is particularly relevant for newer inspectors, it is also valuable for more 

experienced inspectors to enhance their understanding and use of the NIST Handbook 44. This 

course can also provide opportunities for discussion amongst field staff during in-person 

meetings or using web conferencing tools, if available.

This course has been designed as a self-study course. That means it is designed to enable you 

to work on your own, without an instructor. The only materials you will need are the course 

manual and a copy of the most recent edition of NIST Handbook 44; both the course manual 

and NIST Handbook 44 are available for download from the NIST OWM website at no charge. 

You should use a calculator for the exercises that involve computations.

The course is divided into five chapters. Chapter 2 is relatively short and introductory in nature, 

and you can easily complete it in a couple of hours. The other chapters are considerably longer 

and the subject matter is more difficult. You should allow yourself at least several hours to 

complete each of these.

You can set your own pace, but avoid rushing yourself: this material is important and should be 

studied carefully. At the same time, you should, if possible, work on this course steadily until 

you complete it. If you stretch it out too much, you may find that you need to spend more time 

reviewing material you've already covered before proceeding to a new subject.

Note Chapters 2 to 5 of this course each include a quiz (along with answers) on the learning 

concepts covered in the chapter.

https://www.nist.gov/pml/weights-and-measures/legal-metrologydevices/training-materials 

Below is an outline of topics included in this course. Learning objectives for each chapter are 

included in the course material.

• Chapter 1 – Introduction to the Course 

• Chapter 2 - Background

• Chapter 3 – Organization and Format of NIST Handbook 44 

• Chapter 4 - How to Use NIST Handbook 44 

• Chapter 5 - Basic Principles Underlying NIST Handbook 44 
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II. Reference Documents

The following provides links on the NIST OWM website to the current editions of NIST 

Handbooks and/or other documents specifically relevant to the inspection and testing of 

commercial weighing and measuring devices and systems. These documents are available for 

viewing or downloading at no charge. Some documents are available for download either in 

entirety or in individual sections. Note that your state may adopt earlier editions of the NIST 

Handbooks.

1. NIST Handbook 44, Specifications, Tolerances, and Other Technical Requirements for 

Commercial Weighing and Measuring Devices

Current Edition:

https://www.nist.gov/pml/weights-and-measures/publications/nisthandbooks/other-nist-handbooks/other-nist-handbooks-2-3

Earlier Editions from 2000 to Current:

https://www.nist.gov/pml/weights-and-measures/publications/nisthandbooks/other-nist-handbooks/other-nist-handbooks-2

2. NIST Handbook 159, Examination of Grain Moisture Meters Using Air-Oven Reference 

Method Transfer Standards, 2017 Edition

https://nvlpubs.nist.gov/nistpubs/hb/2017/NIST.HB.159-2017.pdf

This Handbook is divided into two parts:

• Part 1: Laboratory Grain Sample Preparation and Testing provides guidance on 

developing grains samples used as standards to test moisture meters.

• Part 2: Field Inspection and Evaluation provides guidance and requirements for 

testing grain moisture meters

III. Newsletter Articles – NIST OWM

NIST OWM staff have developed newsletter articles on a variety of technical topics over the 

years; many of these articles are available for review and/or download from the NIST OWM 

web site. The following articles, listed alphabetically by topic along with the NIST OWM web 

site link, are relevant to the inspection and testing of grain moisture meters (GMMs) and NearInfrared (NIR) Grain Analyzers. Each article takes approximately 10-20 minutes to read.
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1. Accuracy of Measurement

Measure for Measure – Does Accuracy Matter to You? – July 2016

https://www.nist.gov/system/files/documents/pml/wmd/pubs/2016/06/30/W

MConnections-Vol7-Issue4-July2016.pdf

2. Audit Trails – Inspecting Equipment with Audit Trails

Inspecting Equipment with Audit Trails – December 2003 (Article J-007)

https://www.nist.gov/system/files/documents/2017/05/09/J-007.pdf

3. GMM Series – Part 1 - Overview

Grain Moisture Meter (GMM) Series Part 1 – Overview of GMM Series TopicsNovember 2006

(Article C-005)

https://www.nist.gov/system/files/documents/2017/05/09/C_005.pdf

4. GMM Series – Part 2 – Economic Impact 

The Economic Impact of Errors in Moisture Measurements Part 2, Grain Moisture 

Meter Series – March 2007 – (Article C-006)

https://www.nist.gov/system/files/documents/2017/05/09/C-006.pdf

5. GMM Series – Part 3 – Near Infrared Technology 

Grain Moisture Meter (GMM) Series Part 3 - Grain Moisture Meter Measurement 

Technology - Near Infrared – September 2007 – (Article C-007)

https://www.nist.gov/system/files/documents/2017/05/09/C-007.pdf

6. GMM Series – Part 4 – Grain Preparation, Storage, and Meter Testing

Grain Preparation, Maintenance and Storage of Grain Transfer Standards, Equipment 

and Apparatus, and Field Test Procedures – September 2008 – (Article C-008)

https://www.nist.gov/system/files/documents/2017/03/14/c-008.pdf

7. Operation and Calibration of GMMs

What do Grain Moisture Meters Measure and How are They Calibrated? – September 

2006 – (Article C-004)

https://www.nist.gov/system/files/documents/2017/05/09/C-004.pdf
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8. Standards – Thermometers

Get the Lead Out! – March 2006 (Article H-013)

https://www.nist.gov/system/files/documents/2017/05/09/H-013.pdf

9. Standards – Thermometers

NIST Launches New Website to Educate Industry About Alternatives to Mercury 

Thermometers – March 2013, Issue 1

https://www.nist.gov/system/files/documents/2017/05/09/WMConnectionsVol4-Issue1-Feb-25-2013.pdf

10. Suitability – Device Suitability and Application of NTEP CC

Suitability of Installation and Variations of Weighing and Measuring Devices Covered 

by an NTEP CC (Article J-014)

https://www.nist.gov/system/files/documents/2017/05/09/J-014.pdf

11. Technology – New Generation of Grain Moisture Meters

A New Generation of Grain Moisture Meters – February 2012 – (Article C-010)

https://www.nist.gov/system/files/documents/2017/03/14/c-010.pdf

12. Test Procedures and Tolerances – Grain Moisture Meters

Grain Moisture Meter Test Methods and Tolerances – May 2011 – (Article C-009)

https://www.nist.gov/system/files/documents/2017/03/14/c-009.pdf

13. Test Procedures - Grain Moisture Meters

Testing Grain Moisture Meters (GMMs) – May 2004 – (Article C-003)

https://www.nist.gov/system/files/documents/2017/05/09/C-003.pdf

14. Test Procedures - Moisture Basis – NIR Inspection

Near Infrared (NIR) Device Inspection and Moisture Basis – November 2002 – (Article 

C-001)

https://www.nist.gov/system/files/documents/2017/05/09/C-001.pdf
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15. Test Procedures - Reference Methods - Air-Oven 

Grain Moisture Air-Oven Reference Methods in the United States – November 2012 

– (Article C-011)

https://www.nist.gov/system/files/documents/2017/03/14/c-011.pdf

16. Test Procedures - Reference Methods - Test Weight per Bushel 

Determining Reference Test Weight per Bushel Value of Grains – September 2013 –

(Article C-012)

https://www.nist.gov/system/files/documents/2017/03/14/c-012.pdf

17. Test Weight Feature on Grain Moisture Meters

New Requirements for Grain Moisture Meters Capable of Measuring Test Weight –

February 2004 (Article C-002)

https://www.nist.gov/system/files/documents/2017/05/09/C-002.pdf

NIST OWM is continually developing new articles, so be sure to consult our website for any 

articles that may have been added since the issuance of this study guide. Articles organized by 

topic area such as “weighing” or “packaging and labeling” or “metrology” or other technical 

areas can be found at the following address:

https://www.nist.gov/pml/weights-and-measures/weights-and-measuresnewsletter-archives

Complete newsletters published from 2010 to present can be found at the following address:

https://www.nist.gov/pml/weights-and-measures/weights-and-measuresconnection-newsletter-archive
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IV. Instructor-Led Training Opportunities

1. Webinars

NIST OWM periodically offers webinars and on-line presentations on a variety of topics

related to legal metrology, including the inspection activity covered in this guide. OWM is 

currently working to increase its offerings of webinars related to the inspection and testing 

of commercial weighing and measuring devices. Be sure to consult our calendar of events 

to determine if there are any upcoming offerings related to the inspection activity covered 

in this study guide.

https://www.nist.gov/pml/weights-and-measures/about-owm/calendar-events

2. In-Person Training Events

NIST OWM periodically offers classroom-based training classes at various places around the 

U.S. Typically hosted by a weights and measures agency, this training ranges in duration 

from several days to a full week. Be sure to consult our calendar of events at the link 

referenced above for upcoming training events.

V. Technical Guidance and Interpretations

1. NIST OWM Technical Staff

As always, NIST OWM staff are available to provide guidance and interpretations on 

technical issues related to legal metrology. All our technical staff are working remotely and 

remain available via email and phone. If you are holding a virtual meeting to discuss specific 

technical issues, for example, and would like our input on a particular point, we may be able 

to connect with you remotely. All International Legal Metrology work (OIML and other) is 

being maintained. For reference, our technical staff contact list is available on our web site 

at:

https://www.nist.gov/pml/weights-and-measures/about-owm/staff-andtechnical-experts-directory

2. NCWM Final Reports

Changes to NIST Handbooks 44, 130, and 133 are developed through the National 

Conference on Weights and Measures and voted on by state and local weights and 

measures officials. During the development of these changes, weights and measures 

officials, industry, NIST, and other stakeholders present and consider background 
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information and key technical points regarding those changes and their anticipated impact. 

This information is documented in the final reports of the National Conference on Weights 

and Measures (NCWM) Specifications and Tolerances Committee (for NIST Handbook 44) 

and the NCWM Laws and Regulations Committee (for NIST Handbooks 130 and 133. The 

reports also include Committee recommendations; input from the NIST technical advisors;

and the intended application of specific requirements in Handbooks 44, 130, and 133. The 

information in the NCWM reports can be helpful in gaining a deeper understanding of many 

of the specific Handbook requirements, including their intended application and associated 

changes over the years.

Reports issued from 2008 to present are posted on the NIST OWM website at the following 

link:

https://www.nist.gov/pml/weights-and-measures/publications/ncwm-annualreports

Copies of previous reports are available upon request from NIST OWM. A flash drive 

including all NCWM reports from 1905-2017 along with keyword search capability is also 

available upon request when NIST returns to normal operating status.