API 609
Butterfly Valves: Lug- and Wafer-Type
standard by American Petroleum Institute, 05/01/1997
Full Description
Covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for gray iron, ductile iron, bronze, steel, nickel-base alloy, or special alloy butterfly valves that provide tight shutoff in the closed position and are suitable for flow regulation.