Standard Guide for Testing Sheathed Thermocouples, Thermocouples Assemblies, and Connecting Wires Prior to, and After Installation or Service

SIGNIFICANCE AND USE
These test procedures ensure and document that the thermocouple assembly was not damaged prior to or during the installation process and that the extension wires are properly connected.
The test procedures should be used when thermocouple assemblies are first installed in their working environment.
In the event of subsequent thermocouple failure, these procedures will provide benchmark data to verify failure and to help evaluate the cause of failure.
The usefulness and purpose of the applicable tests will be found within each category.
These tests are not meant to ensure that the thermocouple assembly will indicate temperatures accurately. Such assurance derives from proper thermocouple and instrumentation selection and proper placement in the location where the temperature is to be measured. For further information, the reader is directed to MNL 12, Manual on the Use of the Thermocouples in Temperature Measurement2 which is an excellent reference document on metal sheathed thermocouples.
SCOPE
1.1 This guide covers methods for users to test metal sheathed thermocouple assemblies, including the extension wires, just prior to, and after installation or some period of service.
1.2 The tests are intended to ensure that the thermocouple assemblies have not been damaged during storage or installation, to ensure that the extension wires have been attached to connectors and terminals with the correct polarity, and to provide benchmark data for later reference when testing to assess possible damage of the thermocouple assembly after operation. Some of these tests may not be appropriate for thermocouples that have been exposed to temperatures higher than the recommended limits for the particular type.
1.3 The tests described herein include methods to measure the following variables of installed sheathed thermocouple assemblies and to provide benchmark data for determining if the thermocouple assembly is subsequently damaged in operation:
1.3.1 Loop Resistance Thermoelements,
Combined extension wires and the thermoelements,
1.3.2 Insulation Resistance Insulation, thermocouple assembly,
Insulation, thermocouple assembly and extension wires.
1.3.3 Seebeck Voltage:
1.3.3.1 Thermoelements,
1.3.3.2 Combined extension wires and thermocouple assembly.
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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ASTM E1350-07 - Standard Guide for Testing Sheathed Thermocouples, Thermocouples Assemblies, and Connecting Wires Prior to, and After Installation or Service
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1350 − 07
StandardGuide for
Testing Sheathed Thermocouples, Thermocouples
Assemblies, and Connecting Wires Prior to, and After
1
Installation or Service
This standard is issued under the fixed designation E1350; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Thermocouples are widely used in industry and provide reliable service when used within their
specified temperature range. However, if thermocouples fail in service the consequences can range
from negligible to life-threatening. Often, an expensive loss of equipment, product, or operating time
will result. The user should weigh the potential consequences of thermocouple failure when
considering what tests should be performed either prior to, during, or after installation.
This standard is a guide for the field testing of thermocouples, thermocouple assemblies, and their
connecting wires to ensure that they were not damaged during storage, installation, or use rather than
being a guide for acceptance testing of thermocouples as delivered from the vendor.The test methods
range from the most basic tests to assure the thermocouple was properly installed to simple tests
necessaryforfailureanalysis.Thermocoupletestssuchashomogeneity,capacitance,andloop-current
step-response require elaborate equipment and sophisticated analysis and are not included in this
guide.
Faulty installation practices and in-service operation beyond prescribed limits are frequently the
cause of failure in properly made sheathed thermocouples. Many of the most common forms of these
conditions may be detected through use of the test methods described in this document. For further
information, the reader is directed to MNL12, Manual on the Use of Thermocouples in Temperature
2
Measurement, which is an excellent reference document on metal sheathed thermocouples.
1. Scope thermocouples that have been exposed to temperatures higher
than the recommended limits for the particular type.
1.1 This guide covers methods for users to test metal
sheathed thermocouple assemblies, including the extension
1.3 The tests described herein include methods to measure
wires, just prior to, and after installation or some period of
the following variables of installed sheathed thermocouple
service.
assemblies and to provide benchmark data for determining if
the thermocouple assembly is subsequently damaged in opera-
1.2 The tests are intended to ensure that the thermocouple
tion:
assemblies have not been damaged during storage or
1.3.1 Loop Resistance:
installation, to ensure that the extension wires have been
1.3.1.1 Thermoelements,
attached to connectors and terminals with the correct polarity,
andtoprovidebenchmarkdataforlaterreferencewhentesting 1.3.1.2 Combined extension wires and the thermoelements,
to assess possible damage of the thermocouple assembly after 1.3.2 Insulation Resistance:
operation. Some of these tests may not be appropriate for
1.3.2.1 Insulation, thermocouple assembly,
1.3.2.2 Insulation, thermocouple assembly and extension
wires.
1
1.3.3 Seebeck Voltage:
This guide is under the jurisdiction ofASTM Committee E20 on Temperature
Measurement and is the direct responsibility of Subcommittee E20.04 on Thermo-
1.3.3.1 Thermoelements,
couples.
1.3.3.2 Combinedextensionwiresandthermocoupleassem-
Current edition approved May 1, 2007. Published June 2007. Originally
approved in 1991. Last previous edition approved in 2001 as E1350–97 (2001). bly.
DOI: 10.1520/E1350-07.
2
1.4 This standard does not purport to address all of the
Manual on the Use of Thermocouples in Temperature Measurement, MNL 12,
ASTM. Available from ASTM International, www.astm.org. safety concerns, if any, associated with its use. It is the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E1350 − 07
responsibility of the user of this standard to establish appro- temperature-emf characteristics matching the extension wires
priate safety and health practices and determine the applica- or thermoelements they are intended to connect.
bility of regulatory limitations prior to use.
3.2.6.1 Discussion—The temperature-emf characteristics of
the connector parts will match the extension wires or the
2. Referenced Documents
thermoelements only over a specified temperature range.Ther-
3
mocouple connectors are described in Specifications E1129/
2.1 ASTM Standards:
E1129M and E1684.
E230Specification and Temperature-Electromotive Force
(EMF) Tables for Standardized Thermocouples
4. Summ
...

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