Laboratory Metrology

Laboratory Metrology Program Overview

The OWM Laboratory Metrology Program promotes and ensures SI traceability of measurement results for state-level legal metrology laboratory programs across the United States through metrology training and by providing proficiency testing (PT) and laboratory recognition services. Laboratory Metrology also collaborates with the other OWM programs and standards development organizations (SDOs) to maintain and develop documentary standards, technical guidance documents, and other training resources, such as standard operating procedures, good measurement practices, and on-the-job training materials that support state legal metrology laboratory calibration workload. 

Who We Are

Staff members are physical scientists, laboratory metrologists, and program administrators with experience working in local, state, and federal metrology laboratories and as state weights and measures officials. 

What We Do

The OWM Laboratory Metrology Program standards and services underpin the SI traceability of state legal metrology laboratories, which are the custodians of state-level measurement standards. This ensures equity in U.S. trade and commerce and the reference standards for U.S. industry calibration services. 

Training. The Program delivers outstanding technical in-person and online Laboratory Metrology Training designed to meet International Accreditors for Continuing Education and Training (IACET) criteria and needs for a wide range of metrology stakeholders. This includes local, state, and federal government, commercial industry,  and National Metrology Institutes and Designated Institutes (NMI/DIs). Historically, the state-level legal metrology laboratories are the primary benefactors of the provided training.  

In addition to in-person classroom and laboratory-based training, OWM provides metrology training through a Regional Measurement Assurance Program (RMAP). Participants include local, state and federal laboratory metrologists and representatives from the various metrology industries. Learn more about the upcoming 2025 Combined RMAP training event here. 

Proficiency Testing (PT). The Program operates ISO/IEC 17043-compliant Proficiency Testing (PT) services that assess the training effectiveness for the RMAP participants and the traceability of state metrology laboratories to the SI through NIST standards and services. Participants include local, state, federal, and commercial laboratories across the U.S.  

Laboratory Recognition. To promote SI traceability and encourage technical and professional competence among participating individual state-level laboratories, the Program evaluates and provides Laboratory Recognition to these laboratories to NIST Handbook 143, which consists of additional requirements to ISO/IEC 17025. Upon the annual evaluation of a participating laboratory’s ability to deliver reliable calibration services in the areas of its scope (principally mass, volume, length, and temperature), a Certificate of Metrological Traceability is issued and accepted as reciprocity by other state-level legal metrology programs. The current recognition status and certificate for each participating state metrology laboratory are provided here. 

Following successful laboratory recognition, OWM encourages (and partially subsidizes the fees for) state metrology laboratories to pursue further ISO/IEC 17025 accreditation through the NIST National Voluntary Laboratory Accreditation Program (NVLAP).  

Learn more about the cooperative OWM-NVLAP effort to support state metrology laboratory recognition and accreditation here. 

Documentary Standards and Resources. The Program maintains a series of Documentary Standards and Resources that support its metrology training, laboratory recognition services, and proficiency testing (PT) services.  These include the NIST Handbook 105 series, NIST Handbook 143, and several NIST Internal Reports (NISTIRs).  Additional technical guidance documents, such as Good Laboratory Practices (GLPs), Standard Operating Procedures (SOPs), Good Measurement Practices (GMPs) and Calibration Procedures are also available. 

Other NIST Resources

• Calibration Services
• Engineering Metrology Toolbox
• Fluid Flow Group (and Volume)
• Length
• Mass and Force Group
• National Voluntary Laboratory Accreditation Program (NVLAP)
• SI Units, Uncertainties
• Statistical Engineering, Electronic Statistics Handbook
• Thermometry and Humidity
• Traceability Resources