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MSS SP-67-2022
Butterfly Valves
This Standard Practice covers dimensions, design, testing, and marking requirements for butterfly valves. 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).
Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. [mss]