ASTM International Standard Specification for Compacted Mineral-Insulated, Metal-Sheathed, Noble Metal Thermocouples and Thermocouple Cable ASTM E2181/E2181M-19

This specification establishes the requirements for materials and manufacturing, dimensions, inspection and testing, and processing of compacted, mineral-insulated, metal-sheathed Type S (platinum-10 % rhodium versus platinum), Type R (platinum-13 % rhodium versus platinum), and Type B (platinum-30 % rhodium versus platinum-6 % rhodium) noble metal thermocouples, and thermocouple cables with at least one noble metal thermoelement pair. This specification describes both the required processing and testing requirements, and also the optional supplementary testing and quality assurance requirements. Additionally, provisions are made herein for selecting the type of noble metal thermocouple or thermoelements, either magnesia (MgO) or alumina (Al2O3) insulation, and a noble metal alloy or other alternate heat-resistant sheath material. Provisions are also made for selecting a thermocouple measuring junction style and for a transition or termination.