The dissemination of traceability to the International Temperature Scale of 1990 (ITS-90) through comparison calibration of thermocouples, is playing an important role in metrology institutes, secondary laboratories and industrial measurements. The previous studies of the Pt/Pd thermocouples at NIS-Egypt, shows promise of achieving significant improvements uncertainty of temperature measurements up to 960 °C. In this paper we describe the uncertainty assessment on the measurements of the calibration of Pt/Pd thermocouples at fixed point cells up to the freezing point of copper and by the comparison technique following a defined heat treatment at 1100 °C. All the measurements on Pt/Pd thermocouples were carried out using NIS facilities.
