Standard Active Last Updated: May 14, 2021
ASTM E1159-15(2020)e1

Standard Specification for Thermocouple Materials, Platinum-Rhodium Alloys, and Platinum


This specification covers non-insulated platinum rhodium alloys (weight percent composition), and platinum thermo elements. The purity of platinum for use in the negative thermo element of Type R and Type S thermocouples shall be of a specific Grade, as specified. The purity of platinum before alloying for use in the positive thermo element of Type R, S, and both thermo elements of Type B shall also be of a certain grade, as specified. All material to be supplied shall consist of continuous lengths which shall be free of kinks and shall be round and smooth. Any pits or dents that exceed a certain percentage of the diameter shall be cause for rejection of the material. After material has been processed to its final diameter and prior to subsequent anneal, it shall be cleaned to remove all dirt, lubricant, fingerprints, or other foreign residue. The thermoelements shall be such that, when matched as a thermocouple, the EMF output shall meet the tolerance on the initial value of EMF versus temperature as specified.


1.1 This specification covers non-insulated platinum-rhodium alloys (weight percent composition), and platinum thermoelements that meet the requirement of Specification E230/E230M and NIST Monograph 175.2

1.2 This specification does not cover platinum and platinum-rhodium materials, that require a higher purity than specified in 5.1, such as used for temperature coefficient of resistance (TCR) measurements or standards type calibration. For requirements of this superior quality, it is suggested that suppliers of precious metals be contacted.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 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.

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Book of Standards Volume: 14.03
Developed by Subcommittee: E20.13
Pages: 3
DOI: 10.1520/E1159-15R20E01
ICS Code: 17.200.20; 77.120.99