The DIN EN 1555 standards series is the German version of the EN 1555 standard series. They specify general requirements for polyethylene (PE) piping systems used in the field of the supply of gaseous fuels, and the test parameters for the test methods referred to in this standard. They are applicable to PE pipes, fittings and valves, their joints and to joints with pipeline components of other materials intended to be used at a maximum operating pressure, MOP, up to and including 10 bar and at an operating temperature of 20 °C as reference temperature. It also contains specifications for the range of maximum operating pressures and specifies requirements for the colouring of pipeline components and the use of additives. The first part contains general requirements for the piping systems. The second part deals in particular with the pipes, the third part with the fittings and the fourth part with the valves. Part 5 specifies the requirements necessary for fitness for purpose of the system, including the resulting requirements for the joints of the single components of the piping system. The standard series addresses manufacturers, test facilities and users of polyethylene (PE) piping systems. It has the nature of a delivery standard. In particular, the standard contains aspects of quality and product safety. These standards are revisions of the standards published in 2002. The European Standards have been prepared by CEN/TC 155 "Plastics piping systems and ducting systems" the secretariat of which is held by NEN (the Netherlands). The responsible German Committee is Working Committee NA 054-05-08 AA "Kunststoff-Rohrleitungssysteme für die Gasversorgung" ("Plastics piping systems for the supply of gaseous fuels") of FNK.