Generalized Measurement System and Standards:
The term standard is used to denote universally accepted specifications for devices. Components or processes which ensure conformity and interchangeability throughout a particular industry. A standard provides a reference for assigning a numerical value to a measured quantity. Each basic measurable quantity has associated with it an ultimate standard.
Working standards, those used in conjunction with the various measurement making instruments. The national institute of standards and technology (NIST) formerly called National Bureau of Standards (NBS), it was established by an act of congress in 1901, and the need for such body had been noted by the founders of the constitution. In order to maintain accuracy, standards in a vast industrial complex must be traceable to a single source, which may be nationals standards.
The following is the generalization of echelons of standards in the national measurement system.
1. Calibration standards
2. Metrology standards
3. National standards
1. Calibration standards:
Working standards of industrial or governmental laboratories.
2. Metrology standards:
Reference standards of industrial or Governmental laboratories.
3. National standards:
It includes prototype and natural phenomenon of Sl (Systems International), the world wide system of weight and measures standards.