This standard describes 1/2-in. (13mm) through 6-in. (150mm) air-release valvesand 1/2-in. (13-mm) through 20-in. (500-mm) air/vacuum and combination air valves having gray cast-iron or ductile-iron bodies and covers. The valves are designed for use in water systems with maximum working pressures of 300 psig (2,070 kPa [gauge]) and water temperatures ranging from above freezing to a maximum of 125 degrees F (52 degrees C).