This part of EN ISO 1452 gives guidance for the assessment of conformity of compounds/formulations, products, joints and assemblies in accordance with the applicable parts of EN ISO 1452 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 to EN ISO 9001 [1]. NOTE 2 If third-party certification is involved, it is recommended that the certification body is accredited to EN 45011 [2], EN 45012 [3] or EN ISO/IEC 17021 [4], as applicable. In conjunction with part 1 to 5 of EN ISO 1452 (see Foreword) this document is applicable to unplasticized poly(vinyl chloride) (PVC-U) plastics piping systems for water supply and for buried and above-ground drainage and sewerage under pressure.