Fixed point calibrations - CCPI
Fixed Point Calibrations

CCPI Europe’s UKAS Accredited Calibrations Laboratory (No. 0600) (ISO17025) holds some of the tightest uncertainties of measurement or Calibration Measurement Capabilities (CMC’s) granted by UKAS for the calibration of noble metal thermocouples.

This high accuracy level is achieved due to the extensive range of fixed points the CCPI Europe laboratory has in operation.


What is a fixed point in temperature calibration?

A fixed point is a reproducible physical event that has a defined temperature value assigned. An example of a conventional fixed point used in temperature calibrations is the freezing point of a pure metal such as Tin.

Tin, for example, 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 and from the test results, developing an individual emf output curve for the thermocouple.

CCPI Graph

Fixed points used at 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) 1324.29 °C
  • Palladium Carbon (PdC) 1491.16 °C
  • Palladium (Pd) in air 1553.5 °C

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


Check out the CCPI Europe’s laboratories accuracies (CMC)
UKAS Schedule (No. 0600)

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