This specification covers temperature sensors, instrumentation, thermal processing equipment, system accuracy tests, and temperature uniformity tests. These are necessary to ensure that parts or raw materials are heat treated in accordance with the applicable specification(s). It is applicable to all heat treatment of parts and to those heat treatments by producers of raw material which could affect fabrication of properties of parts. This specification is not applicable to heating, or to intermediate heat treatment, by raw material producers to facilitate subsequent operations (e.g., hot or cold working). It is also not applicable to brazing, hot isostatic pressing and coating. The requirements herein pertaining to system accuracy tests and temperature uniformity tests are waived for laboratory equipment used to heat treat specimens in accordance with material specifications providing test instrument(s) and sensor(s) in contact with, or in close proximity to, specimen(s) are used to measure specimen temperature(s). Conformance of raw material heat treating equipment to the requirements herein pertaining to readability of working instruments i waived for a transition period of one year after the date of publication of this document. Conformance of raw material heat treating equipment to other requirements herein is waived for a transition period of six months providing pyrometry conforms to appropriate industry of U.S. Government specifications (e.g., MIL-STD-1684).