Defines the requirements of fitness for purpose of the polyethylene (PE) piping system to be used for the supply of gaseous fuels.

This part of ISO4437 specifies the requirements of fitness for purpose of the polyethylene (PE) piping system to be used for the supply of gaseous fuels. It specifies the definitions of electrofusion, socket fusion, butt fusion, and mechanical joints. It specifies the method of preparation of test piece joints and the tests to be carried out on these joints for assessing the fitness for purpose of the system under normal and extreme conditions. It specifies the test parameters for the test methods referred to in this part of ISO4437. In conjunction with ISO4437-1, ISO4437-2, ISO4437-3, and ISO4437-4, it is applicable to PE pipes, fittings, valves, their joints, and joints with components of PE and other materials intended to be used under the following conditions: the maximum operating pressure (MOP) is based on the design stress, determined from the compound minimum required strength (MRS) divided by the C factor, and taking into account rapid crack propagation (RCP) requirements; a temperature of 20°C as reference temperature for the design basis. NOTE1 For other operating temperatures, derating coefficients are given in AnnexA. NOTE2 It is the responsibility of the purchaser or specifier to make the appropriate selections from these aspects, taking into account their particular requirements and any relevant national regulations and installation practices or codes.