The European Standards DIN EN ISO 15874-1, DIN EN ISO 15874-2, DIN EN ISO 15874-3 and DIN EN ISO 15874-4 replace the standards from March 2004. The most significant modification is the incorporation of another type of material (PP-RCT). Requirements and test methods are specified for components made from PP-H, PP-B, PP-R and PP-RCT, their joints with one another as well as with joints with components made of other plastics and materials intended to be used for hot and cold water installations within buildings for the conveyance of water, whether or not intended for human consumption (domestic systems), and for heating systems. Part 1 contains general specifications such as definitions of terms, classes of application and corresponding service conditions as well as material requirements. Furthermore, Parts 2 and 3 contain separate specifications for pipes or fittings on general, geometrical, mechanical and physical characteristics as well as marking. Part 5 serves as a basis for the assessment of the fitness for purpose of the system, consisting of the single components pipe, fitting and joint. The European Standards have been prepared by CEN/TC 155/WG 16 "Plastic piping systems and ducting systems - Systems for hot and cold water applications" (secretariat: SIS, Sweden) with the active German collaboration of Working Committee NA 119-04-06-05 GUA "Gemeinschaftsunterausschuss NAW/FNK: Warm- und Kaltwasserleitungen (CEN/TC 155/WG 16)" ("Joint Subcommittee NAW/FNK: Hot and cold water supply pipelines (CEN/TC 155/WG 16)") at NAW.