Primary Laboratory

Isotech can calibrate your primary standards to the lowest of uncertainties

Our uncertainties of calibration and procedures have all been scrutinised and agreed with UKAS, who are party to the ILAC-MRA. Each year we are audited by UKAS who check our electrical and thermal standards, examine and witness our procedures and question our uncertainty spreadsheets.

The Primary Laboratory maintains Reference Fixed Point Cells from the Triple Point of Argon (-189.3442°C) through to the Freezing Point of Silver (961.78°C).

The measurement systems in operation comprise the best precision thermometry bridges money can buy in the microK and ASL F900, coupled with Model 670SQ and 96178 Standard Platinum Resistance Thermometers and Tinsley 5685A Standard Resistors the Primary laboratory has a Calibration and Measurement Capability (CMC) comparable if not better than most of the worlds National Metrology Institutes.

Primary laboratory calibration scope

  • Standard Platinum Resistance Thermometers (SPRT)
  • Fixed Point Cells
  • Standard Resistors
  • Au/Pt Thermocouples
  • Noble Metal Thermocouples

Features of NTPL

  • Clear and simple certification - the uncertainty stated on the certificate is for the piece of equipment that has been calibrated.
  • Committed Service - if an SPRT requires annealing prior to calibration the customer will be consulted and the annealing will take place at no extra cost to the customer.


Isotech’s UKAS accredited calibration laboratory, Northern Temperature Primary Laboratory (NTPL), was established in 1980 and has grown to be a full scale laboratory providing calibration to the smallest of uncertainties. Isotech was the first UKAS laboratory to be accredited to calibrate ITS-90 Fixed Point Cells. Our accredited uncertainties are now smaller than many the scope of other accredited laboratories and smaller than most National Measurement Institutes.

Isothermal Technology Ltd
NTPL (Northern Temperature Primary Laboratory)
Pine Grove

UKAS accredited – Accreditation No. 0175

Tel: +44 (0)1704 543830/544611
Fax: +44 (0)1704 544799

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