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Thermometry - Calibration ServicesOrdering Calibrations Services The Thermometry Group maintains the International Temperature Scale (ITS-90) in Canada. It disseminates temperature standards through its calibration service and through support for the INMS Calibration Laboratory Assessment Service (CLAS). Current research is directed towards improvement of both the primary standards of the ITS-90 and instruments and techniques for practical temperature measurements. Contact: Doug Gee ServicesA complete range of temperature calibrations is available for resistance thermometers, liquid-in-glass thermometers, thermistors, thermocouples, and optical pyrometers. Special arrangements can be made to calibrate other temperature-measuring devices. The laboratory normally calibrates only first-class thermometric instruments. It may refuse to undertake certain, or all, methods of calibration for inferior instruments. It can advise clients on the selection, use, and appropriate calibration of thermometers for any aspect of temperature measurement.
FacilitiesThe Group has a complete set of primary standards (calibration equipment and thermometers) which enables it to realize the ITS-90, in accordance with its definition, from 14 K to 2500 K. In addition, there are 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.
FeesOrdering Calibrations Services NEW procedures effective March 23, 2006.
Liquid-In-Glass Thermometers and Digital ThermometersLiquid-in-glass thermometers suitable for calibration are generally of the total immersion, ASTM-designated type with Serial Numbers. These thermometers include an ice-point reference scale which should be routinely monitored. Calibrations are made by comparison with a standard platinum resistance thermometer in a constant temperature bath within the temperature range -80°C to +500°C. A calibration consists of an ice-point reading and typically calibrations at 3 to 5 temperatures within the range of the thermometer. The thermometer is read to approximately one-fifth of a scale division. Hand-held digital thermometers suitable for calibration generally have thermocouple, PRT or thermistor input sensors and a digital readout display calibrated together. Calibrations are made by comparison with a standard platinum resistance thermometer in a constant temperature bath within the temperature range -80°C to +500°C, or by comparison with a standard thermocouple in an electrically heated furnace between 300°C and 1100°C. A calibration consists of measurements at 3 or more temperatures within the range of the thermometer.
Standard Platinum Resistance ThermometersThe 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.
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
Preliminary Preparation and Testing
Capsule-type SPRTs(A33-03-02-02 to A33-03-02-05) Calibrations of capsule-type SPRTs are available for the following temperature ranges:
Long-stem SPRTs and HTPRTs(A33-03-02-06 to A33-03-02-21) The following services are provided for long-stem SPRTs and HTPRTs. The temperature ranges are as shown for each calibration.
Platinum-rhodium ThermocouplesStandard platinum 10% 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. Such a thermocouple will be returned assembled in a pure alumina sheath 46 cm long and 4 mm in diameter, with a pyrex-enclosed reference junction and with 150 cm selected copper leads. Platinum 13%rhodium/platinum thermocouples (type R) of the same construction will also be calibrated under A33-03-03-03.
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 which read directly in terms of temperature. Calibrations are performed by comparison against SPRTs or standard thermocouples which 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.
Radiation ThermometersRadiation 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 20mm may be calibrated in this manner. RT calibrations using Fixed Point blackbody sources (FPBBs) are also available using Indium, Tin, Zinc, Aluminum, and Silver FPBBs. Other radiation thermometers may be calibrated by special arrangement.
Strip Filament LampsTungsten strip-filament lamps (vacuum and gas-filled) may be calibrated for use as transfer standards for the calibration of optical pyrometers. The calibration is performed by comparing the lamps to be calibrated with lamps which have been previously calibrated against blackbody standards using a primary photoelectric pyrometer.
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at 0°C) normally operate between 84 K and 660°C. The high-temperature platinum resistance thermometer (HTPRT) (0.25 to 2.5 