This part of the standard determines the special requirements and tests to be applied to control valves for a range PN 6 to PN 25, the nominal dimensions of which are as defined in Part 1. The Type tests shall be carried out on valves of DN <= 500, by agreement between the supplier and purchaser, for higher DNs. This Part 5 does not deal with the performance of control valve accessories whether or not these form an integral part of the valves.