This standard specifies requirements for residual pressure valves, with or without a non-returnfunction, for gas cylinders and the methods of testing such valves, for type approval.This standard is applicable to valves to be fitted to gas cylinders of up to 150 l water capacity, intended to contain compressed, liquefied or dissolved gases.This standard does not cover valves for fire extinguishers, cryogenic equipment or liquefied petroleum gas. These requirements are in addition to those laid down in ISO 10297.