The calibration accuracy of four type R thermocouples was evaluated from a series of deviations between measured values which were corrected with a SPRT and interpolating thermo-EMFs concerning the JIS for thermocouples. The mean deviation of each thermocouple is found to be about -0.15°C∼+0.10°C with the standard deviation of less than ±0.05°C in the temperature range of 50°C∼950°C.
