This standard covers design, material, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for two types of check valves. Type `A' check valves are short face-to-face as defined in Tables 2A and 2B and can be: wafer, lug, or double flanged; single plate or dual plate; gray iron, ductile iron, steel, nickel alloy or other alloy designed for installation between Class 125 and 250 cast iron flanges as specified in ASME B16.1, between Class 150 and 300 ductile iron flanges as specified in ASME B16.42, between Class 150 - 2500 steel flanges as specified in ASME B16.5, and between Class 150 - 600 steel pipeline flanges as specified in MSS SP-44 or carbon steel flanges as specified in ASME B16.47. Type `B' check valves are long face-to-face as defined in 4.1.2 and can be: flanged or butt-welding; steel, nickel alloy or other alloy designed for installation between Class 150 - 2500 steel flanges as specified in ASME B16.5 or for butt-welding into industry accepted piping systems.