This document, together with prEN 13476-2 and prEN 13476-3, specifies the definitions and general requirements for pipes, fittings and the system based on unplasticized poly(vinyl chloride) (PVC-U), polypropylene (PP) and polyethylene (PE) structured-wall piping systems that are intended for use in non-pressure underground drains and sewers for foul wastewater. NOTE 1 Products complying with this document can also be used in non-pressure underground drains and sewers for surface water. This document is applicable to: a) structured-wall pipes and fittings, which are to be used buried in the ground outside a building structure only; reflected by the marking of products by U ; b) structured-wall pipes and fittings, which are to be used buried in ground both outside (application area code U ) and within a building structure (application area code D ); reflected in the marking of products by UD . In conjunction with prEN 13476-2 and prEN 13476-3, it is applicable to structured-wall pipes and fittings with or without an integral socket with elastomeric ring seal joints, as well as welded and fused joints. This part specifies general aspects and gives guidance concerning a national selection of requirement levels and classes where part 2 and part 3 of this standard provide options. prEN 13476-2 and prEN 13476-3 specify material characteristics, dimensions and tolerances, test methods, test parameters and requirements for pipes with smooth internal and external surfaces, Type A, and pipes with smooth internal and profiled external surfaces, Type B. This document, together with prEN 13476-2 and prEN 13476-3, covers a range of pipe and fitting sizes, materials, pipe constructions, stiffness classes and tolerance classes and offers recommendations 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. NOTE 3 Pipes, fittings and other components conforming to any plastic product standards referred to in Clause 2 can be used with pipes and fittings conforming to this standard, when they conform to the requirements for joint dimensions given in part 2 and part 3 of this standard and to the performance requirements given in Clause 9.