This publication covers isolation valves, control valves, check valves, pressure relief valves, and drain and vent valves in air separation units (ASUs) and their backup and storage piping system. It addresses the design, material selection, manufacturing, cleaning, installation, operation, and maintenance of oxygen service valves operating at temperatures below –22 °F (–30 °C).

Valves in warm service connecting instrumentation devices are excluded from the scope of this publication. Although this publication is for ASUs, some of the principles may be used for other cold oxygen installations.