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.
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.
Copyright ©2024 All Rights Reserved