Specifies the endurance test needed to confirm the ability of hand-operated plastics valves to withstand prolonged use, with repeated closure and opening. Does not specify the ability of valves to withstand adverse conditions; particularly those of chemically aggressive fluid media and/or environments, or excessive fluid velocities and cavitation. Includes values of the parameters needed for the proper performance of the endurance test; there is a reservation that parameters may differ in particular product standards.