This Standard Practice covers dimensions, design, testing, and marking requirements for butterflyvalves. Further reference should be made to the MSS SP-68.
This Standard Practice covers two types of butterfly valves: Type I Valves for tight shut-off (Tested per Section 10.2.1) Type II Valves permitting seat leakage (See Section 10.2.2)
This Standard Practice covers flangeless (wafer-type), single-flange (lug-type), and flanged-endvalves in size NPS 1? through NPS 72, along with grooved-end valves, and shouldered-end valves,with pressure ratings in accordance with the requirements of Sections 3 and 4.