This Technical Specification gives guidance for the assessment of conformity of compounds/formulations, products and assemblies in accordance with EN 1401 1. It applies to those compounds/formulations, products and assemblies intended to be included in the manufacturer’s quality plan as part of the quality management system and for the establishment of third-party certification procedures. NOTE 1 It is recommended that the quality management system conforms to or is no less stringent than the relevant requirements of EN ISO 9001 . NOTE 2 If third-party certification is involved, it is recommended that the certification body is accredited to either EN 45011 , EN 45012  or EN ISO/IEC 17021 , as applicable. NOTE 3 In order to help the reader, a basic test matrix is given in Annex A. In conjunction with EN 1401 1 (see Foreword), this Technical Specification is applicable to piping systems made of unplasticized poly(vinyl chloride) (PVC-U) used for the following puposes: - for non pressure underground drainage and sewerage outside the building structure (application area code "U"), reflected in the marking of products by "U"; - for non-pressure underground drainage and sewerage for both buried in ground within the building structure (application area code "D") and outside the building structure (application area code "U"), reflected in the marking of products by "UD".