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Temperature Calibration Resources

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Calibration is a broad topic and includes the untimate reference sources, such as the national metrology laboratories, who are the custodians of the International Temperature Scale, and those services that are directly traceable to the the national standards.

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Yes, there is an "official" temperature scale. It's based on the true, thermodynamic temperature scale, but the real, working temperature scale is something practical which can be repeatably produced anywhere in the world given the correct practices and equipment. This is a lot like the freezing and boiling points of water but developed and refined to a higher degree (pardon the pun).

It is revised periodically as our technical abilities improve and as those who specialize in the field of metrology (measurement science) are able to come to some consensus. This hyperlink provide detailed information about the newest revision of the temperature scale used in calibration and measurement.

This is the scale which the national labs, or those affiliated to those labs, refer to in the calibration certificates of reference devices that may be used in corporate or university or other measurement laboratories which provide a more local service such as to working instruments in a process plant or experimental apparatus.

The International Temperature Scale of 1990 (ITS-90) :
(A technical paper describing the scale, in fact a site dedicated to the ITS-90 and related topics)

The International Bureau of Weights and Measures (Bureau International des Poids et Measure or BIPM)
The task of the BIPM is to ensure world-wide uniformity of measurements and their traceability to the International System of Units (SI). It does this with the authority of the Convention of the Metre, a diplomatic treaty between fifty-one nations, and it operates through a series of Consultative Committees, whose members are the national metrology laboratories of the Member States of the Convention, and through its own laboratory work. Temperature and Humidty are but two of the principle measurement areas of interest.

Some Calibration Services and National Standards Custodians

NIST's Calibration Service Users Guide
Direct calibrations by the USA custodian of temperature (and other) standards

NIST MEASUREMENT SERVICES: Radiance Temperature Calibrations
An online technical description, in great depth, about the (a) realization and dissemination of ITS-90 above 700C, (b) a description of the facilities in the NIST Radiance Calibration Laboratory, (c) A discussion of the the wavelength calibration, size of source and linearity issues, (d) An explanation of the use and calibration of radiance temperature standards, and, (e) A summary of the values of stability and uncertainty in the ITS-90 Scale at NIST and the expanded uncertainties for ribbon filament lamp, optical pyrometer and infrared radiation thermometer calibrations. In short, a very complete description of the technology behind the calibration services at high temperatures at NIST.

Calibration of High- Temperature Resistance Thermometers
Oak Ridge National Labs,
Instrumentation and Controls Division.

National Research Council of Canada
The Canadian national custodian for standards.

The National Physical Laboratory
The Custodion of standards for The United Kingdom

The Commonwealth Scientific and Industrial Research Organizations, The Australian Standards for Temperature,

Resources for Calibration of Temperature Sensors: Non-Commercial Organizations

The National Conference of Standards Laboratories International (NCSL) home page

About The NCSL

UKAS, The United Kingdom Accreditation Service
The UK service that accredits calibration laboratories for many variables and types of devices including all kinds of temperature sensors and calibrating equipment, e.g. black body sources, baths, lamps etc. The UKAS web site includes a search engine for all accredited calibration labs in the UK, and some outside the UK because UKAS accreditation is recognised worldwide.

Some Useful & Informative Links
(with minimal commercial content)

A calibration resource for all things related to calibration including job openings, equipment, books, standards and much more.

Cal Lab Magazine's Web Site...
A treasure trove of information and links related to all things metrological including temperature.. with links to the national custodians of standards for almost every nation in the world and much, much, much more.

ITS-90 Site
A Web site dedicated to the International Temperature Scale of 1990

Isotech Support CD
Cal NotePad Software, Isotech Technical Info, Evaluation Reports, Isocal-6 Video & Performance Information.

Some (by no means all) Suppliers of Temperature Calibration Equipment, Services and/or Training  

  1. Advanced Sensing Products (USA)
    A secondary standard PRT and precision RTD probe manufacturer. They make own RTD elements to completely control product quality. Provide NIST traceable calibration services with temperature ranging from -189 to 850°C. Customers are in metrology, instrumentation, power industry, turbine manufacturers, and the military.
  2. AAMETEK Denmark A/S
  3. ASL, Temperature Metrology and Calibration
    Known for their RTD bridges and other high quality calibration equipment.
  4. Barber-Colman Industrial Instruments Division and Cii Continental
    Both companies are divisions of Invensys. They design, build and calibrate a full line of sensors including thermocouples, RTDs and furnace atmosphere probes. Cii is in the process of relocating the Barber-Colman sensor products to their new site. They are both ISO-9000 approved.
  5. Burns Engineering, Inc.
  6. Caliso Calibration Toolbox - The calibration management program for scientists and engineers.
  7. eCalibration--'s mission is to be the premier resource for calibration professionals worldwide as a clearinghouse of information and services specific to managing the calibration function within the manufacturing arena.
  8. Cole Parmer Instruments (USA)
    The laboratory equipment supply company has a range of temperature and calibration equipment.
  9. GEC Instruments (USA)
    Precision thermocouple instruments connect to a PC via RS232 serial port or USB. Windows software with built in calibration wizard enables user calibration of individual thermocouples toattain overall system measurement accuracy of better than ± 0.1C including thermocouple wire error. GEC Instruments also provides custom thermocouples and custom thermocouple calibrations.
  10. Hart Scientific(USA)
    Triple Point of water cells, RTDs, training course and very much more. It's an educational experience just visiting their extensive web site and reading their literature.
  11. ICL Labs (USA)
  12. Insco Metrology (USA)
    Temperature calibration services for TCs, RTDs, LiGs traceable to NIST to 1100 C and with their custom-made fixed point cells ( FPs Hg,Ga, In, Sn, Zn, Al, Ag).
  13. Isotech (UK)
    One of the truely educational web sites on temperature metrology; a reknown vendor of quality calibration equipment and services-representatives in all the major countries-the sponsor of the ITS-90 web site.
  14. Omega Engineering
  15. Pond Engineering Laboratories (USA)
    Triple point of water and other fixed points and related equipment and training for realizing the International Temperature Scale of 1990 to very high precision.
  16. Process Instruments, Pittsburgh, PA (USA)
    Supplier of equipment and services to industry for many years, traceable to NIST for all types of temperature sensor calibrations.
  17. Sira Test & Certification Ltd (UK)
    Operates its UKAS approved, traceable temperature calibration facilities approximately 12 miles south of London.
  18. Spectrodyne (Infrared Only) in eastern Pennsylvania. (USA)
    One of the very few sources of independent IR thermometer calibration services-traceable to NIST.
  19. Techne Instruments
    Manufacturers of temperature controled liquid baths used in calibration work.
  20. Tempsens Instruments India
    An ISO 9001/2000 certified manufacturer of all types of temperature sensors and Calibration Baths & Furnaces for Thermocouples & RTDs from -30 to 1500 Deg. C, Black body sources for pyrometer calibration from 50 to 1500 deg C and master sensors for thermocouple Type R,S, or N/K with accredited certificate.They also manufacture high accuracy master RTDs up to 1/10 DIN
  21. Thermo Gauge Instruments Inc.(USA)
    Suppliers of a unique resistance-heated, graphite tube design of low thermal mass, high temperature, precision blackbody furnaces. Many of these special furnaces can be found in National Metrology Labs and the production and development labs of the major IR radiation thermometer makers around the world-Temperatures up to 3000°C.
    Thermo Gauge Instruments, Precision Blackbodies
  22. Yokogawa Instruments
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