If calibration does not use a grand master or intrinsic standard, how is the reference value known?

In the context of calibration, traceability is crucial for ensuring that measurements are accurate and reliable. When calibration does not utilize a grand master or intrinsic standard, the reference value is established through a traceable hierarchy. This means that the measurement instruments are linked to national or international standards that provide a recognized and accepted reference. The traceability ensures that the reference values are obtained from well-defined methods and are verifiable, maintaining the integrity of the measurements.

The traceability chain typically involves the use of established measurement standards, which are maintained by certifying organizations and are periodically verified against higher-order standards. This process allows technicians to ensure that their measurements correlate with widely accepted definitions of measurement units and values, thus affirming their accuracy.

Other methods such as trial-and-error or assumptions do not provide a reliable means of obtaining a reference value due to their subjective or unverified nature. Calibration history may provide insights into previous measurements but does not establish a solid reference framework like traceability does. Therefore, utilizing traceability ensures that measurements are consistently accurate and reliable within a calibration system.