1.1 This specification provides standard dimensions for manual (lever and gear actuator) butterfly valves installed in shipboard piping systems in NPS 2 to NPS 24, inclusive. 1.2 This specification covers conventional and This specification covers standard envelope dimensions for manual (lever and gear actuator) butterfly valves installed in shipboard piping systems. Materials covered by this specification are conventional and ANSI B16.34 class butterfly valves (from NP