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Reference Materials that do not meet all the criteria for certified reference materials are more widely available: the principal difference is the additional evidence of metrological traceability and statement of measurement uncertainty provided on the certificate for certified reference materials.
For instance, in the basement of the NIST's Gaithersburg facility in 2009, when measuring the gravity acting upon Pt‑10Ir test masses (which are denser, smaller, and have a slightly lower center of gravity inside the Kibble balance than stainless steel masses), the measured value was typically within 8 ppb of 9.801 016 44 m/s 2.
NIST had an operating budget for fiscal year 2007 (October 1, 2006 – September 30, 2007) of about $843.3 million. NIST's 2009 budget was $992 million, and it also received $610 million as part of the American Recovery and Reinvestment Act. [18] NIST employs about 2,900 scientists, engineers, technicians, and support and administrative personnel.
Commercial scales have to be National Type Evaluation Program (NTEP) approved or certified. The certification is issued by the National Conference on Weights and Measures (NCWM), in accordance to the National Institute of Standards and Technology (NIST), "Handbook 44" specifications and tolerances, [1] through Conformity Assessment and the Verified Conformity Assessment Program (VCAP) [2]
The international prototype of the kilogram (IPK) is an artefact or prototype that was defined to have a mass of exactly one kilogram.. In metrology (the science of measurement), a standard (or etalon) is an object, system, or experiment that bears a defined relationship to a unit of measurement of a physical quantity. [1]
This NTEP Certificate of Conformance indicates that the device manufacturer has demonstrated the ability to meet applicable requirements for commercial weighing and measuring equipment in the United States as specified in Handbook 44: Specifications and Tolerances and Other Technical Requirements. NTEP certification is required in most states ...
Within a product's supply chain, traceability may be both a regulatory and an ethical or environmental issue. [3] Traceability is increasingly becoming a core criterion for sustainability efforts related to supply chains wherein knowing the producer, workers and other links stands as a necessary factor that underlies credible claims of social, economic, or environmental impacts. [4]
The NIST-4 Kibble balance, which is used to measure weight via electric current and voltage. With this instrument, the measurement of mass is no longer dependent on a defined mass standard and is instead dependent on natural physical constants. Metrology is the scientific study of measurement. [1]