This International standard specifies safety requirements, certain functional requirements, and marking of valves and other components with similar bodies, hereinafter called valves, for use in refrigerating systems including heat pumps. Valves in the sense of this standard include extension pipes. The standard describes the procedure to be followed when designing valve parts subjected to pressure as well as the criteria to be used in the selection of materials. The standard describes methods by which reduced impact values at low temperatures may be taken into account in a safe manner. This standard applies to the design of bodies and bonnets for pressure relief devices, including bursting disc devices, with respect to pressure containment but it does not apply to any other aspects of the design or application of pressure relief devices.