A comprehensive survey of reported thermocouple drift rates since 1972

Thermocouples are widely used in industry, but a commonly encountered difficulty is the thermoelectric drift which causes an unknown change to the thermovoltage over time. A comprehensive survey of the published information on drift rates for Types B, C, D, K, N, R, S, Au/Pt and Pt/Pd thermocouples is presented. The data that is available for thermocouple drift rates is reviewed for each major thermocouple type, and any large gaps in the reported data are stated. The effects of different parameters on the drift rate are summarised, with a particular focus on what happens at different temperatures. The effects of temperature, thermoelement diameter, sheath and/or insulation type, atmosphere and thermocycling on the drift rate are considered (where data is available). This will allow users to assess the likely magnitude of the drift rate of different thermocouples for a given application.