ISO 15996:2017 specifies design, type testing and marking requirements for cylinder valves incorporating residual pressure devices, hereinafter referred to as residual pressure valves (RPVs). This document applies to the following types of RPVs:a) cylinder valves intended to be fitted to refillable transportable gas cylinders;b) main valves (excluding ball valves) for cylinder bundles;c) cylinder valves or main valves with integrated pressure regulator (VIPR);d) valves for pressure drums and tubes;which convey compressed or liquefied gases.NOTE Where there is no risk of ambiguity, cylinders, pressure drums, tubes and cylinder bundles are addressed with the collective term "cylinder" within this document.These requirements are in addition to those in ISO 10297.For RPD stand-alone devices this document can also be applied.ISO 15996:2017 does not apply to RPVs for portable fire extinguishers, cryogenic equipment, low pressure refrigerant gases (cylinder test pressure less than 50 bar), dissolved gases or liquefied petroleum gas (LPG).