Traceability of Surface Temperature Measurements Using Contact Thermometers

Two methods of transferring traceability from contact thermometers calibrated by immersion to thermocouples measuring surface temperature are compared. The temperature of a reference surface is determined (i) by extrapolation from thermometers inserted at different depths, or (ii) by measurement on the surface using a thermally compensated thermocouple. Components of measurement uncertainty are discussed for each technique, and results are compared from 50 deg C to 300 deg C.