This Part of this European Standard specifies the general aspects of polyethylene (PE) piping systems (mains and service pipes) intended for the conveyance of water for human consumption, including raw water prior to treatment. It also specifies the test parameters for the test methods referred to in this standard. In conjunction with other Parts of this European Standard it is applicable to PE pipes, fittings, 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 25 bar 2) ; b) an operating temperature of 20 °C as a reference temperature. NOTE 1 For applications operating at constant temperatures greater than 20 °C and up to 40 °C, see annex A. EN 12201 covers a range of maximum operating pressures and gives requirements concerning colours and additives. 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 guidance or regulations and installation practices or codes.