ASTM E220 : 86(1996)e1

Standard Test Method for Calibration of Thermocouples By Comparison Techniques

Standard Details

1.1 This test method covers the techniques of thermocouple calibration based upon comparisons of thermocouple indications with those of a reference thermometer, different from methods involving the use of fixed points. The precise evaluation of the electromotive force (emf)-temperature relation of a thermocouple is accomplished by determining its emf output at each of a series of measured temperatures. Calibrations are covered over temperature ranges appropriate to the individual types of thermocouples within an over-all range from about -180 to 1700°C (-290 to 2660°F).

1.2 In general, the test method is applicable to bare wire thermocouples or sheathed thermocouples. The latter may require special care to control thermal conduction losses.