Thermometry and humidity calibration services


Please note our prices have changed.


A complete range of temperature and humidity calibrations is available for resistance thermometers, liquid-in-glass thermometers, thermistors, thermocouples, humidity sensors and non-contact thermometers. Special arrangements can be made to calibrate other temperature or humidity measuring devices. The NRC normally calibrates only first-class instruments. We may refuse to undertake certain, or all, methods of calibration for inferior instruments. We can advise clients on the selection, use and appropriate calibration of sensors for any aspect of temperature and/or humidity measurement.


The NRC has a complete set of primary standards (calibration equipment and thermometers), which enables us to realize the ITS-90 , in accordance with its definition, from 14  K to 3200  K . In addition, we have calibration facilities for all the types of thermometers commonly used in the above temperature range. Furnaces, cryostats and measuring equipment are also available for studies of melting and freezing points of high-purity materials as temperature reference points, for annealing of electrical thermometers and for examining the behaviour of temperature-measuring instruments.

Relative humidity and dew-point calibrations are performed in a two-pressure humidity generator traceable to NRC pressure and temperature standards. Calibrations are performed in air. Hygrometers (humidity probes) can be calibrated either directly inside the humidity generator or remotely by connecting them to the generator via air intake tube.


If you wish to order a calibration service, please request a quote from the following technical contact:

Temperature Metrology

Note that fees for measurement and calibration services are subject to change. The fees for service quoted do not include shipping, insurance or the cost of a customs broker. The client must arrange and pay for these services separately.

Calibration number Description Fee/point
A33-03-00-00 Custom temperature standards measurements or services Fee on request
A33-03-00-01 Handling fee. A charge is levied for any instrument that is found to be unsuitable for calibration. This fee covers opening, inspection and return, and is based on the work done prior to the discovery of the fault. $295

Standard platinum resistance thermometers

The standard platinum resistance thermometer (SPRT) defines the ITS-90 within the range 13.8033  K to 1234.93  K , when calibrated at specific sets of defining fixed points, and used with specified reference and deviation functions for interpolation at intervening temperatures. The defining fixed points are listed in the following table.

T90( K ) t90 ( °C ) Fixed point
13.8033 -259.3467 e-Hydrogen triple point.
17.035 -256.115 e-Hydrogen vapour pressure point near 33.3213 kPa .
20.27 -252.88 e-Hydrogen vapour pressure point near 101.292 kPa .
24.5561 -248.5939 Neon triple point.
54.3584 -218.7916 Oxygen triple point.
83.8058 -189.3442 Argon triple point.
234.3156 -38.8344 Mercury triple point.
273.16 0.010 Water triple point.
302.9146 29.7646 Gallium melting point.
429.7485 156.5985 Indium freezing point.
505.078 231.928 Tin freezing point.
692.677 419.527 Zinc freezing point.
933.473 660.323 aluminium freezing point.
1234.93 961.78 Silver freezing point.

The ITS-90 contains a number of overlapping subranges. The calibration of a particular SPRT involves selecting the range over which the thermometer will be used, or the maximum range over which the SPRT may be operated in accordance with the recommendations of the manufacturer. SPRTs may be broadly classified into two types: capsule thermometers and long-stem thermometers. Capsule thermometers are used primarily between 13.8  K and 273  K and, by the nature of their construction, generally become an integral part of the apparatus in which they are used to determine temperature. Long-stem SPRTs (25  Ω at 0  °C ) normally operate between 84  K and 660 °C . The high-temperature platinum resistance thermometer (HTPRT) (0.25 to 2.5  Ω at 0  °C ) may be operated to 961.78  °C .

Preliminary preparation and testing

Calibration number Description Fee/point
A33-03-02-01 This service covers the preliminary preparation and testing of each thermometer. $1,130

Long-stem SPRT s and HTPRTs

The following services are provided for long-stem SPRT s and HTPRTs . The temperature ranges are as shown for each calibration.

Calibration number Description Fee/point
A33-03-02-06 From -189  °C to 0  °C . This includes calibration at the triple points of argon, mercury and water. $2,760
A33-03-02-11 From -38  °C to 30  °C . This includes calibration at the triple points of mercury and water and at the melting point of gallium. $1,855
A33-03-02-12 From -38  °C to 157  °C . Includes triple points of mercury and water and freezing points of indium. $2,760
A33-03-02-15 From 0  °C to 30  °C . This includes calibration at the triple point of water and at the melting point of gallium. $905
A33-03-02-16 From 0  °C to 157  °C . This includes calibration at the triple point of water and the freezing point of indium. $905
A33-03-02-17 From 0  °C to 232  °C . This includes calibration at the triple point of water and the freezing points of indium and tin. $1,855
A33-03-02-18 From 0  °C to 420  °C . This includes calibration at the triple point of water and the freezing points of tin and zinc. $1,855
A33-03-02-19 From 0  °C to 660  °C . This includes calibration at the triple point of water and the freezing points of tin, zinc and aluminium. $2,760
A33-03-02-20 From 0  °C to 962  °C . This includes calibration at the triple point of water and the freezing points of tin, zinc, aluminium and silver. $4,610
A33-03-02-21 Re-issue of a report. $300

Platinum-rhodium thermocouples

Standard platinum 10 percent rhodium/platinum thermocouples (type S) must be at least 90  cm long and made of wire not less than 0.35  mm in diameter. It is recommended that a standard thermocouple be at least 120 cm long and be shipped as bare unstrained wire. This is to facilitate the annealing of the thermocouple wire at high temperature (1300  °C ) by electrical heating prior to assembly. Platinum 13 percent rhodium/platinum thermocouples (type R) of the same construction will also be calibrated under A33-03-03-03.

Calibration number Description Fee/point
A33-03-03-01 This service provides calibration at the freezing points of zinc, aluminium and silver, with an uncertainty of 0.4  °C . $3,325
A33-03-03-02 Platinum-rhodium thermocouples may be calibrated at any of the metal freezing points normally available in the laboratory. $905
A33-03-03-03 Most calibrations of platinum-rhodium thermocouples are performed by comparison with a calibrated type-S ( Pt -10  % Rh / Pt ) or type-R ( Pt -13  % Rh / Pt )
thermocouple in an electrically-heated tube furnace over the range 250  °C to 1100  °C , with an uncertainty of 0.5  °C .

Thermocouples, thermistors and resistance thermometers (including laboratory grade digital thermometers)

This category includes both individual sensors (thermocouples, thermistors, industrial resistance temperature detectors) and various digital instruments that read directly in terms of temperature. Calibrations are performed by comparison against SPRTs or standard thermocouples that determine the calibration temperature. The comparison facilities include a variety of baths, furnaces and cryostats. Each calibration involves A33-03-04-01 and one or more of A33-03-04-02 to A33-03-04-05.

Calibration number Description Fee/point
A33-03-04-01 This service includes the handling and inspection of each instrument received by the laboratory for calibration. $285
A33-03-04-02 This service is performed only when it is necessary to anneal an instrument or to perform additional tests to assess its stability. $305
A33-03-04-03 This service calibrates thermocouples within the range 300  °C to 1100  °C within an electrically-heated tube furnace by comparison with a type-S thermocouple as the standard. $715
A33-03-04-04 A high-temperature furnace with a molybdenum disilicide heating element is available for calibrations within the range 1100  °C to 1700  °C .This service tests one instrument at one
calibration temperature within the specified range. Separate fees apply to each instrument and each calibration temperature.
A33-03-04-05 Within the range -80  °C to 500  °C , comparisons are carried out in stirred liquid baths (alcohol, water, oil, nitrate salts) with an SPRT as the standard. $180
A33-03-04-06 Comparison near the boiling point of liquid nitrogen (approximately -196  °C ). $280

Radiation thermometers

Radiation thermometers (RTs) are calibrated using a wide variety of variable temperature blackbody sources (VTBBs) covering a total range of -40  °C to 2500  °C . For temperatures below 1000  °C , the blackbodies are measured with a standard platinum resistance thermometer (SPRT) or a Au : Pt standard thermocouple traceable to the NRC realization of the international temperature scale of 1990 (ITS-90). For temperatures over 1000  °C , the blackbody is measured with a radiance temperature transfer standard calibrated in accordance with the ITS-90. Radiation thermometers with a field-of-view (spot size) up to and including 20  mm may be calibrated in this manner. RT calibrations using fixed point blackbody sources (FPBBs) are also available using indium, tin, zinc, aluminium, and silver FPBBs . Other radiation thermometers may be calibrated by special arrangement.

Calibration number Description Fee/point
A33-03-05-01 This service is for the calibration of a Radiation thermometer.The client must first contact the laboratory to confirm the calibration range and number of temperature points,
and to schedule the calibration. There may be additional charges for multiple ranges or additional points.


Calibration number Description Fee/point
A33-03-06-00 This service includes the handling and inspection of each instrument received by the laboratory for calibration. $225

Dew point hygrometers

Hygrometers scaled in the units of dew point (or frost point) can be calibrated in the dew-point range from -35 °C to 30 °C . Each calibration involves A33-03-06-00 and one or more of A33-03-06-01.

Calibration number Description Fee/point
A33-03-06-01 This service provides calibration for a dew point hygrometer using a humidity generator. The Charge for A33-03-06-00 also applies. $255

Relative humidity sensors

Hygrometers scaled in the units of relative humidity can be calibrated in the relative humidity range from 10 % rh to 95 % rh at air temperatures ranging from 10 °C to 30 °C . Each calibration involves A33-03-06-00 and one or more of A33-03-06-02.

Calibration number Description Fee/point
A33-03-06-02 This service provides calibration for a relative humidity sensor using a humidity generator. The Charge for A33-03-06-00 also applies. $255