The NIST Handbooks and NCWM: A Brief History

The U.S. Constitution (Article I, Section 8, Clause 5) grants Congress the power to “fix the standard of weights and measures”. The NIST Organic Act also authorizes NIST to engage in implementing activities to carry out this function, including “cooperat[ing] with the States in securing uniformity in weights and measures laws and methods of inspection” [15 U.S.C. § 272(c)(4)]. NIST’s statutory role to assure uniformity in the U.S. legal metrology system has been embodied in legal metrology standards published in NIST Handbooks (since the early 1900s) and include device specifications; uniform laws and regulations; methods for checking contents of packaged goods; and various other Handbooks, guidance documents, and test procedures.

Though NIST is not a regulatory agency, these documentary standards serve as “model” laws and regulations to be adopted as legal requirements by Federal, State, and local regulatory agencies. These laws, regulations, and procedures are used to regulate and ensure equity for consumers and sellers in commercial transactions based on weight and measure in a wide range of applications, from grocery scales to charging devices for electric vehicles to emerging areas such as e-commerce transactions and hemp product labeling.

NIST and the National Conference on Weights and Measures (NCWM) have been closely associated for over 100 years and share the mutual goal and responsibility of facilitating uniformity in weights and measures laws, regulations, standards, and practices. The National Bureau of Standards (NBS; now NIST) held the “First Annual Meeting of Sealers of Weights and Measures of the United States” (now NCWM) in 1905 where State representatives discussed the lack of uniform standards and regulatory oversight for weighing and measuring devices used in commerce and in law enforcement activities. NBS published the first legal metrology standards in 1918 as Miscellaneous Publication No. 1 Manual of Inspection and Information for Weights and Measures Officials. Now titled NIST Handbook 44 Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, all 50 States adopt this handbook.

Through this enduring and interwoven cooperation, NCWM provides a forum for weights and measures officials, industry representatives, and consumer groups together with NIST Technical Advisors to work cooperatively to propose, develop, and ultimately adopt uniform code and technical requirements which are published as standards in NIST Handbooks. As managed by NCWM, this current process is used to develop and adopt standards that are maintained by NIST in Handbooks 44, 130, and 133.