This part of EN 13476, together with EN 13476-1, specifies the definitions and 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 to be used for non-pressure underground drainage and sewerage systems. This part is applicable to pipes and fittings with smooth internal and external surfaces, designated as Type A. It specifies test methods and test parameters as well as requirements. This part is applicable to: a) structured-wall pipes and fittings, which are intended to be used buried underground outside the building structure; reflected in the marking of products by “U”; b) structured-wall pipes and fittings, which are intended to be used buried underground both outside (application area code “U”) and within the building structure (application area code “D”); reflected in the marking of products by “UD”. This part 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 covers a range of pipe and fitting sizes, materials, pipe constructions, stiffness classes, application classes, and tolerance classes and gives recommendations concerning colours.