This standard covers only iron-body, bronze-mounted, nonassisted, swing-check valves, 2-24 in. (50-600 mm) NPS, with mechanical-joint or flanged ends that are installed horizontally in water systems. The manufacturer should be consulted for special conditions. Check valve sizes covered by this standard are 2, 2 1/2, 3, 4, 6, 8, 10, 12, 16, 20 and 24 in. (50, 65, 75, 100, 150, 200, 250, 300, 400, 500 and 600 mm) NPS. Sizes refer to the nominal diameter of the waterway through the inlet and outlet connections and the seat ring. The following design and installation conditions are not covered by this standard. 1.1.4.1 Swing-check valves for use in lines conveying water of unusual corrosivity are not covered by this standard. 1.1.4.2 Conditions of water hammer, hydraulic pulsation, and excessive operating noise are beyond the scope of this standard and require special design and construction consideration.
