This document specifies the characteristics and describes test methods for check and non-return valves for CO2, inert gas or halocarbon gas fire extinguishing systems.Non-return and check valves allow the passage in the direction of flow and they prevent flow in the reverse direction.This document is applicable to check valves installed between container valve and manifold and non-return valves installed in pilot lines, except those valves which are tested in combination with non-electrical control devices.