As the title says, in this article i am going to discuss about the measurement standards that have been used even in the present date.
A standard of measurement is a physical representation of the unit of the measurement.
These terms are applied to a piece of equipment having a known measure of physical quantity. Each standard is an invention of the human being to facilitate or make possible of the measurement process. One of the most important responsibilities of a government is to set and maintain standards, thereby provided a commonly accepted basis of comparison.
This is the flow of standards as below:
These are defined on the basis of international agreements. They are regularly evaluated and checked against absolute measurement in terms of fundamental units.
These are maintained at the international bureau of weights and measure at serves near pairs and are not available to ordinary uses of measuring instruments for purpose of comparison or calibration.
The main function of the primary is the verification and calibration of the secondary standards. They are maintained by the national standards laboratories (NSL) or the stored is government lockers in different part of the world.
They are independently calibrated by absolute measurement and each of the national laboratories. The results of those measurement are compared heading to a world average figure for the primary standards.
The primary is the ultimate against which secondary' are compared. They are available for use outside the national laboratories.
These are the basics reference standards used in the industrial measurement laboratories. These standards are maintained by the particular industry and over checked locally against other reference standards in the area. The industrial laboratories are entirely responsible for maintainability and calibration of the secondary standards.
The secondary standards are normally sent to the national standards laboratories on the regular basics for its calibration and comparison against primary standards. After calibration they are sent back to the industrial user with a certification of their measured values in terms of the primary standards.
These are the principle tools of a measurement laboratories. they are to check and calibrate general laboratory instrument for accuracy and performance are to perform comparison measurement in industrial application. It may be less accurate and less expensive.