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Laboratory Metrology Program


The OWM Laboratory Metrology Program provides the basis for ensuring traceability of state weights and measures standards to NIST. It also conducts Fundamentals of Metrology, Mass, Volume and Advanced Mass training for metrologists from the states, industry, and other countries.

State legal metrology laboratories are custodians at the State level of measurement standards that serve as the basis for ensuring equity in the marketplace and as reference standards for calibration services for indigenous industry. As part of its program to encourage a high degree of technical and professional competence in such activities, the National Institute of Standards and Technology (NIST) Office of Weights and Measures (OWM) has developed performance standards and formalized procedures for Recognition of State legal metrology laboratories on a voluntary basis. Certificates of Metrological Traceability are issued upon evaluation of the laboratory's ability to make reliable metrological measurements (principally mass, volume, length, and temperature).


The OWM Laboratory Metrology Program consists of six formal Regional Measurement Assurance Program (RMAP) groups as shown in this map. The RMAPS include the Caribbean Measurement Assurance Program (CaMAP), the Southwestern Assurance Program (SWAP), the Southeastern Measurement Assurance Program (SEMAP), the Northeastern Measurement Assurance Program (NEMAP), the MidAmerica Measurement Assurance Program (MidMAP), and the Western Regional Assurance Program (WRAP). Participants include weights and measures laboratories and other government laboratories, such as Los Angeles County (LAC) and the U.S. Department of Agriculture, Grain Inspection Packers and Stockyards Administration (USDA-GIPSA).



Can you describe the new definition of the kilogram? Can you describe how a Watt Balance operates? Watch these two NIST videos to get a great overview and get started on your challenge! The watt balance lets researchers determine the mass of an object indirectly by determining two quantities: the strength of the magnetic field, and the current running through a coil of wire. The NIST "D.I.Y." Watt Balance, made with LEGO (R) bricks, is a science project that teaches the principles used in the international kilogram redefinition effort. For more information, see For the journal paper with instructions for building your watt balance, see For additional information, see these additional links: and

SOP 18/19 Calibration of Open Neck Field Standard Test Measures

See the new video podcast of a calibration of a 5 gal graduated neck test measure. Please download and read SOP 18 and 19 prior to viewing.

Ice Point Calibration

Greg Strouse, Leader of the NIST Thermodynamic Metrology Group, and his colleague Luis Chavez (NIST guest researcher from Costa Rica / LACOMET) show how to properly realize an ice point calibration for digital thermometers used in the field, specifically for vaccine storage.


General Information:
301-975-4004 Telephone
301-975-8091 Facsimile

100 Bureau Drive, M/S 2601
Gaithersburg, MD 20899-2601