Thermometry and humidity
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:
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.
|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.||$265|
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
|A33-03-02-01||This service covers the preliminary preparation and testing of each thermometer.||$1,020|
Long-stem SPRTs and HTPRTs
The following services are provided for long-stem SPRTs and HTPRTs. The temperature ranges are as shown for each calibration.
|A33-03-02-06||From -189 °C to 0 °C. This includes calibration at the triple points of argon, mercury and water.||$2,500|
|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.||$1,680|
|A33-03-02-12||From -38 °C to 157 °C. Includes triple points of mercury and water and freezing points of indium.||$2,500|
|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.||$815|
|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.||$815|
|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.||$1,680|
|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.||$1,680|
|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.||$2,500|
|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.||$4,180|
|A33-03-02-21||Re-issue of a report.||$270|
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.
|A33-03-03-01||This service provides calibration at the freezing points of zinc, aluminium and silver, with an uncertainty of 0.4 °C.||$3,010|
|A33-03-03-02||Platinum-rhodium thermocouples may be calibrated at any of the metal freezing points normally available in the laboratory.||$815|
|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.
|A33-03-04-01||This service includes the handling and inspection of each instrument received by the laboratory for calibration.||$255|
|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.||$275|
|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.||$645|
|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.||$160|
|A33-03-04-06||Comparison near the boiling point of liquid nitrogen (approximately -196 °C).||$250|
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.
|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.
|A33-03-06-00||This service includes the handling and inspection of each instrument received by the laboratory for calibration.||$200|
Dew point hygrometers
Hygrometers scaled in the units of dew point (or frost point) can be calibrated in the dew-point range from -25 °C to 70 °C. Each calibration involves A33-03-06-00 and one or more of A33-03-06-01.
|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.||$225|
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 0 °C to 70 °C. Each calibration involves A33-03-06-00 and one or more of A33-03-06-02.
|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.||$225|
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