scope:

This standard decribes only iron-body, nonassisted, swing-check valves, 2 in. through 24 in. (50mm through 600-mm) NPS, with mechanical-joint or flanged ends that are installed in approximately level settings in water systems. The manufacturer should be consulted for special conditions. Check valve sizes described in this standard are 2-, 2 1/2-, 3-, 4-, 6-, 8-, 10-, 12-, 14-, 16-, 18-, 20-, and 24-in. (50-, 65-, 75-, 100-, 150-, 200-, 250-, 300-, 350-, 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.

Seating Types. Check valves may be of the metal-to-metal, resilient-to-metal, or resilient-to-coated seat construction as illustrated in Figure 1.

Hinge arm types. Check valves may incorporate either a metal or resilient hinge arm as illustrated in Figure 1.

Waterway types. Swing-check valves may be of the clear waterway design (where the disc in the full open position swings clear of the waterway) or the full waterway design (where the disc in the full open position is not clear of the waterway, but the body is enlarged to provide full waterway area around the disc).

Pressure ratings. The working water pressure shall be a minimum of 175 psig (1,200 kPa) for check valves with diameters of 2-in. through 12-in. (50-mm through 300-mm) NPS inclusive. The working water pressure shall be a minimum of 150 psig (1,030 kPa) for check valves 14-in. through 24-in. (350-mm through 600 mm) NPS inclusive. The working water temperature shall not exceed 125 degrees F (52 degrees C).

Conditions not described. The following design and installation conditions are not described in this standard.

Swing-check valves for use in lines conveying water of unusual corrosivity are not described in this standard. Example: Water with a pH less than 6.

Conditions of water hammer, hydraulic pulsation, and excessive operating noise are beyond the scope of this standard and require special design