ASTM E574-23

Standard Specification for Duplex, Base Metal Thermocouple Wire With Glass Fiber or Silica Fiber Insulation

ABSTRACT
This specification sets forth the requirements for duplex, types E, J, K, N and T thermocouple wire, insulated with E-glass, S-glass, amorphous silica fiber or polycrystalline fiber. This specification presents the requirements for impregnated and non-impregnated fiber insulated thermocouple wire for normally accepted industrial use. The material shall be classified as follows: Class A-Duplex; Class B-Duplex; Class C-Duplex; Class D-Duplex; Class E-Duplex; and Class F-Duplex. Thermoelements shall be solid thermocouple grade materials with a smooth, bright finish and shall be fully annealed prior to insulating. Individual thermoelements shall be covered with a braid, or double wrap (one wrap in each direction) of glass fibers, a braid of glass fibers, or braid of fibers.
SIGNIFICANCE AND USE
4.1 This specification presents the requirements for impregnated and non-impregnated fiber-insulated thermocouple wire for normally accepted industrial use, but does not attempt to define such usage.  
4.2 A supplement contains the requirements for insulated thermocouple wire that will be exposed to high humidity. The purchase order or inquiry shall specify if the requirements in this supplement are required.
SCOPE
1.1 This specification sets forth the requirements for duplex, types E, J, K, N and T thermocouple wire, insulated with E-glass, S-glass, amorphous silica fiber or polycrystalline fiber.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2023
• ICS: 17.200.20 - Temperature-measuring instruments
• Technical Committee: E20 - Temperature Measurement
• Drafting Committee: E20.12 - Thermocouples - Specifications

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E574 − 23 An American National Standard
Standard Specification for
Duplex, Base Metal Thermocouple Wire With Glass Fiber or
1
Silica Fiber Insulation
This standard is issued under the fixed designation E574; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This specification sets forth the requirements for duplex, 3.1 Definitions—The definitions given in Terminology E344
types E, J, K, N and T thermocouple wire, insulated with shall apply to this standard.
E-glass, S-glass, amorphous silica fiber or polycrystalline fiber.
3.2 Definitions of Terms Specific to This Standard:
1.2 The values stated in SI units are to be regarded as 3.2.1 amorphous silica fiber, n—continuous filament of
standard. The values given in parentheses are for information heat-insulating material whose principal constituent is amor-
only. phous silica.
1.3 This standard does not purport to address all of the 3.2.2 duplex wire, n—matched pair of parallel, solid
safety concerns, if any, associated with its use. It is the thermoelements, individually insulated (double wrap or braid)
responsibility of the user of this standard to establish appro- with insulating fibers and a fiber braid of the same material
priate safety, health, and environmental practices and deter- overall.
mine the applicability of regulatory limitations prior to use.
3.2.3 E-glass, n—family of calcia-alumina-silicate glasses
1.4 This international standard was developed in accor-
that are used for general purposes and most electrical applica-
dance with internationally recognized principles on standard-
tions.
ization established in the Decision on Principles for the
3.2.4 impregnate, v—to saturate the fiber insulation of wires
Development of International Standards, Guides and Recom-
with a high-temperature electrical insulating compound to form
mendations issued by the World Trade Organization Technical
a moisture barrier around the wires and to inhibit fraying of the
Barriers to Trade (TBT) Committee.
fibers.
2. Referenced Documents 3.2.5 polycrystalline fiber, n—continuous polycrystalline
filament of heat-insulating material whose composition is
2
2.1 ASTM Standards:
alumina, boria, and silica in an approximate ratio of 3:1:2,
D1125 Test Methods for Electrical Conductivity and Resis-
respectively.
tivity of Water
3.2.6 S-glass, n—family of magnesia-alumina-silicate
E207 Test Method for Thermal EMF Test of Single Thermo-
glasses with a higher tensile strength and higher softening
element Materials by Comparison With Reference Ther-
temperature than E-glass.
moelement of Similar EMF-Temperature Properties
E220 Test Method for Calibration of Thermocouples By
4. Significance and Use
Comparison Techniques
E230/E230M Specification for Temperature-Electromotive
4.1 This specification presents the requirements for impreg-
Force (emf) Tables for Standardized Thermocouples
nated and non-impregnated fiber-insulated thermocouple wire
E344 Terminology Relating to Thermometry and Hydrom-
for normally accepted industrial use, but does not attempt to
etry
define such usage.
4.2 A supplement contains the requirements for insulated
thermocouple wire that will be exposed to high humidity. The
1
This specification is under the jurisdiction of ASTM Committee E20 on
purchase order or inquiry shall specify if the requirements in
Temperature Measurement and is the direct responsibility of Subcommittee E20.12
on Thermocouples - Specifications.
this supplement are required.
Current edition approved May 1, 2023. Published May 2023. Originally
approved in 1976. Last previous edition approved in 2019 as E574 – 19. DOI:
5. Classification
10.1520/E0574-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
5.1 Class A–Duplex—E-glass fiber insulated, impregnated
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
with a high-temperature electrical insulating compound and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. color-coded in accordance with Specification E230/E230M.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E574 − 23
TABLE 1 Maximum Outside Transverse Dimensions of Insulated
5.2 Class B–Duplex—E-glass fiber insulated (Note 1) not
Wire
impregnated and not color-coded.
Uninsulated Thermoele
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E574 − 19 E574 − 23 An American National Standard
Standard Specification for
Duplex, Base Metal Thermocouple Wire With Glass Fiber or
1
Silica Fiber Insulation
This standard is issued under the fixed designation E574; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification sets forth the requirements for duplex, types E, J, K, N and T thermocouple wire, insulated with E-glass,
S-glass, amorphous silica fiber or polycrystalline fiber.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.3 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D1125 Test Methods for Electrical Conductivity and Resistivity of Water
E207 Test Method for Thermal EMF Test of Single Thermoelement Materials by Comparison With Reference Thermoelement
of Similar EMF-Temperature Properties
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
E230/E230M Specification for Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples
E344 Terminology Relating to Thermometry and Hydrometry
3. Terminology
3.1 Definitions—The definitions given in Terminology E344 shall apply to this standard.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 amorphous silica fiber, n—continuous filament of heat-insulating material whose principal constituent is amorphous silica.
3.2.2 duplex wire, n—matched pair of parallel, solid thermoelements, individually insulated (double wrap or braid) with insulating
fibers and a fiber braid of the same material overall.
1
This specification is under the jurisdiction of ASTM Committee E20 on Temperature Measurement and is the direct responsibility of Subcommittee E20.12 on
Thermocouples - Specifications.
Current edition approved May 1, 2019May 1, 2023. Published June 2019May 2023. Originally approved in 1976. Last previous edition approved in 20132019 as
E574 – 13.E574 – 19. DOI: 10.1520/E0574-19. 10.1520/E0574-23.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E574 − 23
3.2.3 E-glass, n—family of calcia-alumina-silicate glasses that are used for general purposes and most electrical applications.
3.2.4 impregnate, v—to saturate the fiber insulation of wires with a high-temperature electrical insulating compound to form a
moisture barrier around the wires and to inhibit fraying of the fibers.
3.2.5 polycrystalline fiber, n—continuous polycrystalline filament of heat-insulating material whose composition is alumina, boria,
and silica in an approximate ratio of 3:1:2, respectively.
3.2.6 S-glass, n—family of magnesia-alumina-silicate glasses with a higher tensile strength and higher softening temperature than
E-glass.
4. Significance and Use
4.1 This specification presents the requirements for impregnated and non-impregnated fiber-insulated thermocouple wire for
normally accepted industrial use, but does not attempt to define such usage.
4.2 A supplement contains the requirements for insulated thermocouple wire that will be exposed to high humidity. The purchase
order or inquiry shall specify if the requirements in this supplement are required.
5. Classification
5.1 Class A–Duplex—E-glass fiber insulated, impregnated with a high-temperature electrical insulating compound and color-
coded in accordance with Specification E230/E230M.
5.2 Class B–
...