Like any other piece of equipment, a measurement artifact must be maintained. Obviously, it has to be in working order in general. However, what is more important is that it be operating within specified parameters and providing measurements that are traceable to a known source or sources. This paper provides a general overview of calibration and certification. It also discusses some key terminology and methods.
Metrology is the doctrine of measuring and includes three major subjects: the international definition of units, realization of the unit by means of scientific methods, and the establishment of traceability for the documentation to the accuracy of the measurement. Metrology is also defined as the science that deals with measurement. Metrology is important because it is the basis for calibration, or certifying, all measurement equipment.
Legal metrology, which is used in many industries, is defined as securing the accuracy of a measurement, when the measurement could have any influence on human health or safety and the transparency of financial transactions. This is evident in custody transfer applications and is one of the main reasons that having certified equipment traceable to a standard is necessary and also requires understanding by the parties involved in the transaction.