This document specifies the general aspects of polyethylene (PE) piping systems in the field of the supply of gaseous fuels. It also specifies the test parameters for the test methods referred to in this document. In conjunction with Parts 2 to 5 of EN 1555, this document is applicable to PE pipes, fittings, and valves, their joints and to joints with components of other materials intended to be used under the following conditions: a) a maximum operating pressure, MOP, up to and including 10 bar1 at a reference temperature of 20 °C for design purposes; b) an operating temperature between -20 °C and 40 °C. NOTE 1 – For operating temperatures between 20 °C and 40 °C, derating coefficients are defined, see EN 1555-5 . EN 1555 (all parts) covers a range of maximum operating pressures and gives requirements concerning colours. NOTE 2 – 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.