ASTM E235-03
(Specification)Specification for Thermocouples, Sheathed, Type K and Type N, for Nuclear or for Other High-Reliability Applications
Specification for Thermocouples, Sheathed, Type K and Type N, for Nuclear or for Other High-Reliability Applications
SCOPE
1.1 This specification covers the requirements for sheathed, Type K and N thermocouples for nuclear service. Depending on size, these thermocouples are normally suitable for operating temperatures to 1652 °F (900 °C); special conditions of environment and life expectancy may permit their use at temperatures in excess of 2012 °F (1100 °C). This specification was prepared specifically to detail requirements for using this type of sheathed thermocouple in nuclear environments. This specification can be used for sheathed thermocouples which are required for laboratory or general commercial applications where the environmental conditions exceed normal service requirements. The intended use of a sheathed thermocouple in a specific nuclear application will require evaluation by the purchaser of the compatibility of the thermocouple, including the effect of the temperature, atmosphere, and integrated neutron flux on the materials and accuracy of the thermoelements in the proposed application. This specification does not attempt to include all possible specifications, standards, etc., for materials that may be used as sheathing, insulation, and thermocouple wires for sheathed-type construction. The requirements of this specification include only the austenitic stainless steels and other alloys as allowed with Specification E 585/E 585M for sheathing, magnesium oxide or aluminum oxide as insulation, and Type K and N thermocouple wires for thermoelements (see Note 1).
1.2 General Design—Nominal sizes of the finished thermocouples shall be 0.0400 in. (1.016 mm), 0.0625 in. (1.588 mm), 0.125 in. (3.175 mm), 0.1875 in. (4.763 mm), or 0.250 in. (6.350 mm). Sheath dimensions and tolerances for each nominal size shall be in accordance with . The classes of thermocouples covered by this specification are as follows:
1.2.1 Class 1 (grounded)—Measuring junction electrically connected to conductive sheaths, and
1.2.2 Class 2 (ungrounded)—Measuring junctions are electrically isolated from conductive sheaths and from reference ground.
1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E 235 – 03
Standard Specification for
Thermocouples, Sheathed, Type K and Type N, for Nuclear
1
or for Other High-Reliability Applications
This standard is issued under the fixed designation E 235; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.3 The values stated in inch-pound units are to be regarded
as the standard. The values given in parentheses are for
1.1 This specification covers the requirements for sheathed,
information only.
Type K and N thermocouples for nuclear service. Depending
1.4 This standard does not purport to address all of the
on size, these thermocouples are normally suitable for operat-
safety concerns, if any, associated with its use. It is the
ing temperatures to 1652 °F (900 °C); special conditions of
responsibility of the user of this standard to establish appro-
environment and life expectancy may permit their use at
priate safety and health practices and determine the applica-
temperaturesinexcessof2012°F(1100°C).Thisspecification
bility of regulatory limitations prior to use.
was prepared specifically to detail requirements for using this
type of sheathed thermocouple in nuclear environments. This
2. Referenced Documents
specificationcanbeusedforsheathedthermocoupleswhichare
2
2.1 ASTM Standards:
required for laboratory or general commercial applications
A 262 Practices for Detecting Susceptibility to Intergranu-
where the environmental conditions exceed normal service
lar Attack in Austenitic Stainless Steels
requirements. The intended use of a sheathed thermocouple in
E 3 Practice for Preparation of Metallographic Specimens
a specific nuclear application will require evaluation by the
E 45 Test Methods for Determining the Inclusion Content
purchaser of the compatibility of the thermocouple, including
of Steel
the effect of the temperature, atmosphere, and integrated
E 94 Guide for Radiographic Examination
neutron flux on the materials and accuracy of the thermoele-
E 112 Test Methods for Determining Average Grain Size
ments in the proposed application. This specification does not
E 165 Test Method for Liquid Penetrant Examination
attempt to include all possible specifications, standards, etc.,
E 220 Test Method for Calibration of Thermocouples by
for materials that may be used as sheathing, insulation, and
Comparison Techniques
thermocouple wires for sheathed-type construction. The re-
E 230 Specification for Temperature-Electromotive Force
quirements of this specification include only the austenitic
(EMF) Tables for Standardized Thermocouples
stainless steels and other alloys as allowed with Specification
E 344 Terminology Relating to Thermometry and Hydrom-
E 585/E 585M for sheathing, magnesium oxide or aluminum
etry
oxide as insulation, and Type K and N thermocouple wires for
E 585/E 585M Specification for Compacted Mineral-
thermoelements (see Note 1).
Insulated, Metal-Sheathed, Base Metal Thermocouple
1.2 General Design—Nominal sizes of the finished thermo-
Cable
couplesshallbe0.0400in.(1.016mm),0.0625in.(1.588mm),
E 780 Test Method for Measuring the Insulation Resistance
0.125 in. (3.175 mm), 0.1875 in. (4.763 mm), or 0.250 in.
of Sheathed Thermocouple Material at Room Temperature
(6.350 mm). Sheath dimensions and tolerances for each nomi-
E 839 Test Methods for Sheathed Thermocouples and
nal size shall be in accordance with Table 1. The classes of
Sheathed Thermocouple Material
thermocouples covered by this specification are as follows:
E 883 Guide for Reflected-Light Photomicrography
1.2.1 Class 1 (grounded)—Measuring junction electrically
E 1652 Specification for Magnesium Oxide and Aluminum
connected to conductive sheaths, and
Oxide Powder and Crushable Insulators Used in the
1.2.2 Class 2 (ungrounded)—Measuring junctions are elec-
Manufacture of Metal-Sheathed Platinum ResistanceTher-
trically isolated from conductive sheaths and from reference
mometers, Base Metal Thermocouples, and Noble Metal
ground.
Thermocouples
1
This specification is under the jurisdiction of ASTM Committee E20 on
2
Temperature Measurement and is the direct responsibility of Subcommittee E20.04 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
on Thermocouples. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Nov. 1, 2003. Published January 2004. Originally Standards volume information, refer to the standard’s Document Summary page on
e1
approved in 1964. Last previous edition approved in 1996 as E 235 – 88 (1996) . the ASTM website.
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