This Handbook describes the procedures followed in evaluating State (and a few other jurisdictional) legal
metrology laboratories for competence. To be formally Recognized, a laboratory must satisfy general and technical
requirements for each measurement area in which recognition is desired (see Appendix B). This program is
managed by the WMD.
The general requirements in sections 4 and 5 incorporate ISO/IEC 17025:2005 (as adopted by the NVLAP
Calibration Laboratories Accreditation Program) and address internationally accepted quality management practices
for calibration and testing laboratories. In addition to ISO/IEC 17025 and NVLAP requirements, sections 4 and 5
contain additional general requirements as “notes” that are specific for State legal metrology laboratories. (See
Section 7, References.)
The technical criteria in Section 6 amplify general criteria (ISO/IEC 17025) for each specific measurement
parameter to be used as needed. Technical requirements of the WMD recognition program are nearly identical to
the NVLAP guidelines published in the NIST/NVLAP Handbook 150-2F (Dimensional) and 150-2G (Mechanical),
Calibration Laboratories Technical Guides; however, while WMD does not operate a formal accreditation program
it does use the technical section as requirements rather than as guidelines. The technical requirements include
demonstration that: 1) suitable test equipment, calibration standards, defined test procedures, and the general
facilities necessary for good metrological services are available; and 2) that staff have a comprehensive
understanding of calibration, measurement, and test requirements and are capable of applying them.