ASTM_E_1350_-_13.pdf

Designation:E135013Standard Guide forTesting Sheathed Thermocouples,ThermocouplesAssemblies,and Connecting Wires Prior to,and AfterInstallation or Service1This standard is issued under the fixed designation E1350;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThermocouples are widely used in industry and provide reliable service when used within theirspecified temperature range.However,if thermocouples fail in service the consequences can rangefrom insignificant to life-threatening.Often,a costly loss of equipment,product,or operating time willresult.The user should weigh the potential consequences of thermocouple failure when consideringwhich 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 theirconnecting wires to ensure that they were not damaged during storage,installation,or use rather thanbeing a guide for acceptance testing of thermocouples as delivered from the vendor.The test methodsrange from basic tests to verify that the thermocouple was properly installed to tests necessary forfailure analysis.Thermocouple tests such as homogeneity,capacitance,and loop-current step-responserequire elaborate equipment and sophisticated analysis and are not included in this guide.Faulty installation practices and in-service operation beyond prescribed limits are frequently thecause of failure in properly made sheathed thermocouples.Many of the most common types of theseapplication errors may be identified through use of the test methods described in this document.Forfurther information,the reader is directed to MNL 12,Manual on the Use of Thermocouples inTemperature Measurement,2which is an excellent reference document on metal sheathed thermo-couples.1.Scope1.1 This guide covers methods for users to test metalsheathed thermocouple assemblies,including the extensionwires just prior to and after installation or some period ofservice.1.2 The tests are intended to ensure that the thermocoupleassemblies have not been damaged during storage orinstallation,to ensure that the extension wires have beenattached to connectors and terminals with the correct polarity,and to provide benchmark data for later reference when testingto assess possible damage of the thermocouple assembly afteroperation.Some of these tests may not be appropriate forthermocouples that have been exposed to temperatures higherthan the recommended limits for the particular type.1.3 The tests described herein include methods to measurethe following characteristics of installed sheathed thermo-couple assemblies and to provide benchmark data for deter-mining if the thermocouple assembly has been subsequentlydamaged in operation:1.3.1 Loop Resistance:1.3.1.1 Thermoelements,1.3.1.2 Combined extension wires and thermoelements.1.3.2 Insulation Resistance:1.3.2.1 Insulation,thermocouple assembly,1.3.2.2 Insulation,thermocouple assembly and extensionwires.1.3.3 Seebeck Voltage:1.3.3.1 Thermoelements,1.3.3.2 Combined extension wires and thermocouple assem-bly.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is the1This guide is under the jurisdiction of ASTM Committee E20 on TemperatureMeasurement and is the direct responsibility of Subcommittee E20.04 on Thermo-couples.Current edition approved June 1,2013.Published July 2013.Originally approvedin 1991.Last previous edition approved in 2007 as E1350 07.DOI:10.1520/E1350-13.2Manual on the Use of Thermocouples in Temperature Measurement,MNL 12,ASTM.Available from ASTM International,www.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3E230 Specification and Temperature-Electromotive Force(EMF)Tables for Standardized ThermocouplesE344 Terminology Relating to Thermometry and Hydrom-etryE608/E608M Specification for Mineral-Insulated,Metal-Sheathed Base Metal ThermocouplesE780 Test Method for Measuring the Insulation Resistanceof Mineral-Insulated,Metal-Sheathed Thermocouples andThermocouple Cable at Room TemperatureE839 Test Methods for Sheathed Thermocouples andSheathed Thermocouple CableE1129/E1129M Specification for Thermocouple ConnectorsE1684 Specification for Miniature Thermocouple Connec-torsE2181/E2181M Specification for Compacted Mineral-Insulated,Metal-Sheathed,Noble Metal Thermocouplesand Thermocouple CableMNL 12 Manual on the Use of Thermocouples in Tempera-ture Measurement3.Terminology3.1 DefinitionsThe defi