thermocouples

Thermodynamic Quantities

Thermocouples, Thermocouple Materials, Thermometer Indicators

Technical Contacts:
Karen Garrity (32010C-32101C, 32150S)
Tel: 301-975-4818
E-mail: karen.garrity@nist.gov

C. Dawn Cross (32110C-32147C)
Tel: 301-975-4822
E-mail: dawn.cross@nist.gov

Please contact the technical staff before shipping instruments or standards to the address listed below.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8363
Gaithersburg, MD 20899-8363

Comparison Calibrations, Temperature Measured with Thermocouple (TC):
Service ID Number	TC Type	Temp Range ºC	Points	Min. Length (mm)	Temp. ( ºC)	Expanded Uncert., k=2 (ºC)	Fee ($)
32010C	S	0 to 1450	1 ºC or 1 ºF Interv. Table	700	0 to 1100 1450	0.3 1.6	973
32020C	R	0 to 1450	1 ºC or 1 ºF Interv. Table	700	0 to 1100 1450	0.3 1.6	973
32030C	B	0 to 1750	1 ºC or 1 ºF Interv. Table	1000	0 to 800 800 to 1100 1450 1750	(3 µV) 0.3 1.6 2.4	1434
32031C	B	800 to 1750	1 ºC or 1 ºF Interv. Table	1000	800 to 1100 1450 1750	0.6 1.6 2.4	973
32040C	E	0 to 1000	4 to 15	700	0 to 1000	0.9	973
32041C	J	0 to 760	4 to 15	700	0 to 760	0.7	973
32042C	K	0 to 1100	4 to 15	700	0 to 1100	1	973
32043C	N	0 to 1100	4 to 15	700	0 to 1100	1	973
32044C	T	0 to 400	4 to 15	700	0 to 400	0.4	973
32050C	Comparison calibration, two point minimum, per point, for all items above						432/pt
32060C	Each additional table of results at 1 ºC or 1 ºF intervals, for type S, R, or B at later date						279
32070C	Thermocouple materials tested against Pt Thermoelectric standard, 4 to 15 points, 700 mm minimum lengths						973

Calibration at Metal Freezing Points, Minimum TC Wire Diameter 0.4 mm, Freezing Point Determination at Au, Ag, Al, and Zn
Service ID Number	TC Type	Temp Range ºC	Points	Min. Length (mm)	Temp. (ºC)	Expanded Uncert. k=2 (ºC)	Fee ($)
32090C	S or R	0 to 1450	Table 1 ºC or 1 ºF Interv. and equations to generate table	1000	at freezing points 0 to 1100 1450	0.1 0.1 1.6	2192
32091C	Type S or T, freezing point determination, per point, two point minimum						690

Calibration of Digital Thermometer Indicator or Portable Potentiometer
Service ID Number	Description of Services	Fee ($)
32100C	Indicator or Potentiometer, first dial or range	997
32101C	Indicator or Potentiometer, each additional dial or range	563

Comparison Calibration of Thermocouples or Thermocouple Materials Tested against Pt Thermoelectric Standard, Temperature Measured with Standard Platinum Resistance Thermometer, Minimum TC Wire Length 1.0 m, 2 Point Minimum
Service ID Number	Description of Services	Fee ($)
32110C	Range -110 ºC to 315 ºC and Liquid N₂ (-196 ºC) or -166 ºF to 600 ºF and Liquid N₂ (-321 ºF), Expanded Uncertainty 0.4 ºC	505/pt
32120C	316 ºC to 550 ºC or 601 ºF to 1022 ºF, Expanded Uncertainty 0.5 ºC	505/pt

Table at one degree intervals for Type T thermocouple for any of the following options: (The cost of the table will be in addition to the calibration per point covered under fee schedule services numbered 32110C-32120C.)
Service ID Number	Description of Services	Fee ($)
32150S	Special Tests of Thermocouples and Thermocouple Materials	At Cost

Fees are subject to change without notice.

NOTE: Due to the extra time involved in calibrating sheathed thermocouples, a surcharge of 20% of the cost of calibrating bare-wire thermocouples will be added to the relevant fees listed above.

Thermocouples, Thermocouple Materials and Thermometer Indicators (32010C-32147C)

Calibration services for all commonly used types of thermocouples are provided by NIST from -196 °C to 1750 °C depending upon the wire or thermocouple type. The thermocouples are calibrated by one or a combination of three general methods, depending on the thermocouple type, the temperature range, and the uncertainty required. All three methods provide traceability to the ITS-90. In the first method, thermocouples are calibrated by comparison with a reference thermocouple maintained at NIST. In the second method, thermocouples are calibrated by comparison with a standard platinum resistance thermometer. In the third method, thermocouples are calibrated at four defining fixed-point temperatures on the ITS-90: the freezing points of Zn, Al, Ag, and Au. Below 0 °C, the thermocouple calibration is performed in a cryostat; above 0 °C, stirred liquid baths, metal freezing-point cells, and electric tube-type furnaces are employed for the calibrations. Vacuum or inert gas furnaces are also available for testing thermocouples.

Only the bare wires are required to perform the thermocouple calibrations. It is preferable not to send insulating and protecting tubes as the rate of breakage of these in shipment is high. If the thermocouple is furnished mounted (as in a protection tube assembly), a nominal charge will be made for dismantling the mounting and the various parts will be returned to the sender without reassembling them. Minimum thermocouple length requirements listed in the Service ID Number tables are exclusive of lead wire. Lead wires (for connections) should not be sent with thermocouples. All thermocouple calibration data furnished in reports will be on the basis of a reference junction temperature of 0 °C (32 °F). The calibration results will be given in °C or °F, as requested by the customer. The calibration of a thermocouple will not be undertaken if it will likely not yield the specified expanded uncertainty or if it possesses unusual characteristics that would prevent the performance of the calibration or test at a reasonable cost. Only unused base-metal thermocouples and thermocouple materials will be accepted for test.

All uncertainties are expressed as expanded uncertainties and vary with test temperature. In cases where a range of temperatures is given, the stated expanded uncertainty is the maximum of the expanded uncertainties over this range of temperatures.

Special Tests of Thermocouples and Thermocouple Materials (32150S)

For requirements not covered by calibrations described above, special arrangements may be made by consulting one of the specified staff members.

References-Thermocouples

ASTM Standard E 220-86(96), Standard Method for Calibration of Thermocouples by Comparison Techniques, Annual Book of ASTM Standards 14.03, 94, Amer. Soc. For Test. and Matls., Philadelphia, PA (1997).

ASTM Standard E 230-96, Standard Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples, Annual Book of ASTM Standards 14.03, 106, Amer. Soc. for Test. And Matls., Philadelphia, PA (1997).

ASTM Standard E 1751-95, Standard Guide for Temperature Electromotive Force (EMF) Tables for Non-Letter Designated Thermocouple Combinations, Annual Book of ASTM Standards 14.03, 456, Amer. Soc. For Test And Matls., Philadelphia, PA (1996).

International Electrotechnical Commission Standard, Thermocouples, Part I: Reference Tables, IEC Publication 584- 1, Intl. Electrotech. Com., (1994).

Assessment of Uncertainties of Thermocouple Calibrations at NIST, D. Ripple, G. W. Burns, and M. G. Scroger, NISTIR 5340 (1994).

Manual on the Use of Thermocouples in Temperature Measurement, ASTM MNL 12, Amer. Soc. for Test. And Matls., Philadelphia, PA (1993).

Temperature-Electromotive Force Reference Functions and Tables for the Letter-Designated Thermocouple Types Based on the ITS-90, G. W. Burns, M. G. Scroger, G. F. Strouse, M. C. Croarkin, and W. F. Guthrie, Natl. Inst. Stand. Technol. Mongr. 175 (1993).

The International Temperature Scale of 1990 (ITS-90), H. Preston-Thomas, Metrologia 27, 3-10 (1990), Metrologia 27, 107 (1990).

NIST Measurement Services: The Calibration of Thermocouple and Thermocouple Materials, G. W. Burns and M. G. Scroger, Natl. Inst. Stand. Technol. Spec. Publ. 250-35 (April 1989).

Program questions: Calibrations

Phone: 301-975-2200, Fax: 301-975-2950

NIST, 100 Bureau Drive, Stop 8363, Gaithersburg, MD 20899-8363