1.1 This specification covers the design, construction, testing and operating requirements for self-contained pressure-reducing valves for air or nitrogen systems. 1.2 The values stated in this specification in inch-pounds units are to be rega This specification covers the design, construction, testing, and operating requirements for self-contained pressure-reducing valves for air or nitrogen systems. Pressure-reducing valves shall be either: type I - inlet outlet end connections of the same