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Temperature Calibration - UKAS
Contact Thermometer and Infrared Thermometer Calibration

Our UKAS temperature laboratory uses a range of reference platinum resistance thermometers, noble metal thermocouples, stirred liquid baths, specially designed isothermal calibration furnaces and black body sources to provide a comprehensive facility for cost effective thermometer calibration or temperature probe calibration over the range -80ºC to 1,200ºC.

Both contact thermometers or temperature probes such as thermocouples, prts and dial thermometers; and non-contact infrared thermometers and thermal imaging cameras are covered. We can even calibrate temperature sources such a dry block calibrators or calibration baths.

We are also able to offer stand alone UKAS calibration of digital thermometer readouts (without a temperature probe). As these are essentially an electrical instrument they are calibrated in our electrical laboratory.

The calibration uncertainties detailed below are typical examples of our best calibration and measurement capability for a reasonably repeatable thermometer. The final uncertainties quoted on the calibration certificate will include an allowance for the actual repeatability of the thermometer under test during the calibration. If the thermometer was submitted with its own readout and hence calibrated as a system, then an additional allowance will be included in the uncertainty budget to cover the resolution of the thermometer readout.

For more information, give us a call on 0845 241 1533 or send an enquiry from our contact page.

Platinum Resistance Thermometer Calibration (PRTs / RTDs)

Best UKAS Temperature Calibration Uncertainties (for a stable 4 wire PRT)...

±0.013ºC at -80ºC
±0.011ºC at -50ºC
±0.007ºC at 0ºC
±0.010ºC at 20ºC
±0.015ºC at 160ºC
±0.016ºC at 260ºC
±0.032ºC at 420ºC
±0.055ºC at 660ºC

Industrial 2, 3 and 4 wire PRTs will have a larger uncertainty.

Thermocouple Calibration (Base Metal Types)

Thermometer probes and also thermocouple compensation or thermocouple extension cable, over the relevant range.

Typical UKAS Calibration Uncertainties...

±0.15ºC from -80ºC to 420ºC
±0.20ºC from 420ºC to 660ºC
±1.20ºC from 660ºC to 1100ºC
±2.10ºC from 1100ºC to 1200ºC

The above uncertainties are typically our best for most high quality stable base metal thermocouples. A typical industrial thermocouple will attract a larger uncertainty. Over the -80ºC to 250ºC temperature range we able able to significantly improve on these uncertainties for thermocouples that have an integral cold junction. The process is however time consuming and quite expensive, and for most applications, unnecessary.

Platinum Thermocouple Calibration

Thermometer probes and also noble metal extension cable or type 'U' thermocouple compensation cable, over the relevant range.

Typical UKAS Calibration Uncertainties...

±0.50ºC from 20ºC to 660ºC
±1.20ºC from 660ºC to 1100ºC
±2.10ºC from 1100ºC to 1200ºC

Again, these are typically our best uncertainties for most high quality stable platinum thermocouples. Typical industrial thermocouples will attract a larger uncertainty. Over the 0ºC to 250ºC temperature range we can significantly improve on these uncertainties for thermocouples or that have an integral cold junction.

Calibration of Indicating Thermometers (temperature probes with readout, calibrated as a system)

The device under test may be an electronic display with an attached probe. All temperature probe or thermometer types are covered, including PRT, thermistor or thermocouple.

Dial thermometer and chart recorder type devices are also covered.

The basic calibration uncertainty will usually be a little better than the uncertainties achievable for 4 wire PRTs, but with an additional allowance for repeatability of the device under test and resolution of its readout.

Calibration of Dry Block Temperature Calibrators or Calibration Baths

Typical UKAS Temperature Calibration Uncertainties...

±0.035ºC from -80ºC to 0ºC
±0.032ºC from 0ºC to 100ºC
±0.04ºC from 100ºC to 250ºC
±0.06ºC from 250ºC to 425ºC
±0.09ºC from 425ºC to 660ºC
±1.1ºC from 660ºC to 1100ºC
±2.0ºC from 1100ºC to 1200ºC

Infrared Thermometer Calibration (Radiation Thermometer)

Typical UKAS Infrared Thermometer Calibration Uncertainties...

±0.8ºC from 20ºC to 100ºC
±1.2ºC from 100ºC to 200ºC
±1.9ºC from 200ºC to 300ºC
±2.1ºC from 300ºC to 400ºC
±2.6ºC from 400ºC to 500ºC

UKAS accredited infrared thermometer calibration can currently be undertaken over the above range. Any infrared results that fall outside of the above range may be included on the UKAS calibration certificate for completeness but will not be UKAS accredited.

Calibration of Thermal Imagers (Infrared Thermal Imaging Camera)

Thermal imaging cameras that are able to display a measured radiant temperature should be calibrated. Our temperature ranges and uncertainties for UKAS thermal imager calibration will be similar to those quoted for an infrared thermometer calibration. 

For more information, give us a call on 0845 241 1533 or send an enquiry from our contact page. 

ITS-90
The International Temperature Scale of 1990

The international measurement community defines a temperature scale which is sufficiently reproducible and accurate to satisfy most practical requirements. This scale is revised periodically, the latest revision being the International Temperature Scale of 1990 (ITS-90).

ITS-90 approximates the true thermodynamic scale by specifying a number of fixed points along the scale, such as the triple point of mercury -38.8344°C , the triple point of water 0.01°C , the melting point of gallium 29.7646°C, and so on. These fixed points are selected because their temperatures are fixed by a physical process and hence are highly reproducible anywhere in the world. ITS-90 also specifies highly reproducible types of thermometers to interpolate between these fixed points.

We use ITS-90 as the reference scale when carry out temperature calibration work.

Temperature Calibration
Typical Manufacturers
Ametek, Braun, Comark, Cropico, Digitron, Druck, Eurotherm, Flir, Fluke, Hart, Isotech, Jofra, Land, Omega, Omron, Raytek, Testo
Typical Instrument Types
Dial Thermometer, Digital Thermometer Readout, Dry Block Calibrator, Ear Thermometer, Freezer, Hot Block, Infrared Thermometer Calibration, Oven, Platinum Thermometer, PRT, RTD Probe, Soldering Iron, Temperature Probe, Temperature Chart Recorder, Temperature Sensor, Thermal Imager, Thermocouple, Thermistor, Tympanic Thermometer