NF EN 28233

<p class="MsoBodyText"><span lang="EN-GB">This document specifies a test method for the determination of the opening, closing and running torque of thermoplastics valves.</span></p> <p class="MsoBodyText"><span lang="EN-GB">This document is applicable to all types of manually operable thermoplastics valves, with or without actuator, intended to be used for the transport of fluids.</span></p> <p class="Note"><span lang="EN-GB">NOTE 1<span style="mso-tab-count: 1;">        </span>Examples of valve types tested with this method are in ISO 4437-4, ISO 16135, ISO 16136, ISO 16138, ISO 16139, ISO 16486-4, ISO 21787, EN 1555-4^[¹³^] and EN 12201-4^[¹⁴^].</span></p> <p class="MsoBodyText"><span lang="EN-GB">This document does not specify the relationship between the torque and its possible increase after prolonged use of the valve under a specific working condition or wear/chemical aggression of the materials.</span></p> <p class="Note"><span lang="EN-GB">NOTE 2<span style="mso-tab-count: 1;">        </span>Concerning the chemical aggression of the materials, a collection of data is reported in ISO/TR 10358 concerning the endurance test necessary to confirm the ability of hand-operated plastics valves to withstand prolonged use with repeated opening and closing operations. Further information is provided in ISO 8659.</span></p>