1.1 ,This specification covers the requirements for metal-sheathed industrial platinum resistance thermometers (PRT's) suitable for direct immersion temperature measurement. It applies to PRT's with an average temperature coefficient of resistance between 0 and 100 ,°,C of 0.385 ,%/°,C and nominal resistance at 0 ,°,C of 100 Ω, or other specified value. This specification covers PRT's suitable for all or part of the temperature range ,−,200 to 650 ,°,C. The resistance-temperature relationship and tolerances are specified as well as physical, performance, and testing requirements.