Fixed Point Calibration

Our extensive range of pure metal fixed point cell furnaces allows us to offer fixed point calibration for thermocouples and platinum resistance thermometers over the operational range required by customers, all at a competitive price.

What is fixed point calibration in temperature?

Firstly, a fixed point is a reproducible physical event that has a defined temperature value assigned on the ITS90. An example of a conventional fixed point used in temperature calibrations is the freezing point of a pure metal such as Tin.
Tin freezes (goes through the transition from a liquid to a solid) at 231.928 °C

How do you calibrate a reference standard thermocouple?

The emf output of a thermocouple is measured when tested during a fixed-point transition and therefore the absolute value and difference from standard output tables can be established for that temperature point. A reference thermocouple calibration is conducted by measuring the output of the thermocouple at a number of these fixed points as well as from the test results. This therefore develops an individual emf output curve for the thermocouple.


For more information or to speak to one of our temperature measurement experts, get in touch!

Fixed Points used in the CCPI Europe Calibration Laboratory;

  • Triple point of Water 0.01 °C
  • Tin (Sn) 231.928 °C
  • Zinc (Zn) 419.527 °C
  • Aluminium (Al) 660.323 °C
  • Silver (Ag) 961.78 °C
  • Gold (Au) 1064.18 °C
  • Cobalt Carbon (CoC) 1324.02 °C
  • Palladium Carbon (PdC) 1491.16 °C
  • Palladium (Pd) in air 1553.5 °C


The CoC and PdC fixed points unlike most eutectic conventional pure metal fixed points are examples of a new range of metal carbide fixed points developed by the NPL (National Physical Laboratory) to help increase accuracies in the high temperature range above 1100 °C.