INTERNATIONAL TEMPERATURE SCALE OF 1990 (ITS-90)|
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.
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.
International Temperature Scale of 1990 (ITS-90)
technical paper describing the scale, in fact a site dedicated to the ITS-90 and
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.
Calibration Services and National Standards Custodians
Calibration Service Users Guide
Direct calibrations by the USA custodian of temperature (and other) standards
MEASUREMENT SERVICES: Radiance Temperature Calibrations
An online technical description, in great depth, about the (a) realization and
dissemination of ITS-90 above 700°C, (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.
of High- Temperature Resistance Thermometers
Oak Ridge National Labs, Instrumentation
and Controls Division.
Research Council of Canada
Canadian national custodian for standards.
National Physical Laboratory
The Custodion of standards for The United Kingdom
The Commonwealth Scientific and Industrial Research Organizations, The Australian
Standards for Temperature,
for Calibration of Temperature Sensors: Non-Commercial Organizations
National Conference of Standards Laboratories International (NCSL) home page
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.
Useful & Informative Links
(with minimal commercial content)
calibration resource for all things related to calibration including job openings,
equipment, books, standards and much more.
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.
A Web site
dedicated to the International Temperature Scale of 1990
Cal NotePad Software, Isotech Technical Info, Evaluation Reports,
Isocal-6 Video & Performance Information.
(by no means all) Suppliers of Temperature Calibration Equipment, Services and/or
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.
Temperature Metrology and Calibration
Known for their RTD bridges and
other high quality calibration equipment.
Barber-Colman Industrial Instruments Division and
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.
Calibration Toolbox - The calibration management program for scientists
eCalibration.com'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.
Parmer Instruments (USA)
The laboratory equipment supply company has a
range of temperature and calibration equipment.
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 ± 0.1°C including thermocouple wire
error. GEC Instruments also provides custom thermocouples and custom thermocouple
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.
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).
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.
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.
Instruments, Pittsburgh, PA (USA)
Supplier of equipment and services
to industry for many years, traceable to NIST for all types of temperature sensor
Test & Certification Ltd (UK)
Operates its UKAS approved, traceable temperature calibration facilities approximately
12 miles south of London.
(Infrared Only) in eastern Pennsylvania. (USA)
One of the very few sources of
independent IR thermometer calibration services-traceable to NIST.
Manufacturers of temperature controled liquid baths used
in calibration work.
- 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
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.
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