1.1 API 609 standard covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for gray iron, ductile iron, bronze, steel, nickel-based alloy, or special alloy butterfy valves.
1.2 The following two categories of butterfy valves are included:
a) Category A—Manufacturer’s rated cold working pressure (CWP) butterfy valves, usually with a concentric disc and seat confguration. Sizes covered are NPS 2 to NPS 60 for valves having ASME class 125 or class 150 fange bolting patterns.
b) Category B—ASME class and pressure-temperature-rated butterfy valves that have an ofset seat and either an eccentric or a concentric disc confguration. Sizes covered are listed below:
— for lug and wafer, class 150 and 300: NPS 2 to NPS 60;
— for lug and wafer, class 600: NPS 3 to NPS 60;
— for double-fanged short and long pattern, class 150, 300, and 600: NPS 3 to NPS 60;
— for butt-welding ends, class 150, 300 and 600: NPS 3 to 60;
Information to be specifed by the purchaser is shown in Annex B.
1.3 Valve confgurations include double-fanged, lug- and wafer-type with facings that permit installation between ASME and MSS fanges and butt-welding ends. Confgurations conform to the standards and specifcations listed in Section 2. Typical valve construction and nomenclature for valve parts are shown in Annex C.