This International Standard specifies requirements for residual pressure valves, with or without a non-return function, for gas cylinders and the methods of testing such valves, for type approval. This International 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 International 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.