Traceability of temperature measuring instruments

Generally speaking, improving process efficiency means guaranteeing the accuracy of the values delivered by measuring equipment. To meet this need, which applies to all physical quantities, we need reliable references and the means to transfer these references from one stage of the calibration chain to another, i.e. from the national reference to the industrial measurement. The process just described is nothing more than the implementation of methods designed to establish the "traceability" of measurements.

This dossier seeks to illustrate the notion of traceability within calibration chains, using the example of temperature measurement. Temperature is a variable that influences a large number of scientific, technical and industrial processes, and is therefore measured thousands of times every day.

After a brief description of the French calibration system, the "Temperature" calibration chain is presented, based on the means and methods used to connect temperature measurement instruments. Methods for assessing the uncertainties associated with the calibration process are then illustrated, using the example of comparison calibration of a thermoelectric couple.