scope:

This International Standard specifies a test method for the determination of the opening and closing torque of thermoplastics valves. This International Standard applies to all types of thermoplastics valves intended to be used for the transport of fluids according to ISO 16135, ISO 16136, ISO 16138, ISO 16139, ISO 21787. It does not specify the relationship between the torque and its possible increase after valve prolonged use at specific working condition or materials wear/chemical aggression. NOTE - Concerning the chemical aggression of the materials, a collection of data is reported in ISO/TR 10358[1], concerning the endurance test necessary to confirm the ability of hand-operated plastics valves to withstand prolonged use, with repeated opening and closure, information are given in ISO 8659[2].