scope:

This document specifies a classification and a description of imperfections likely to be encountered in thermoplastic welded joints. This document applies to the following welding processes: - heated tool welding; - electrofusion welding; - hot gas welding; - extrusion welding. This document applies to the following group of materials: - PVC-C; - PVC-U including PVC-NI, PVC-RI, PVC-HI; - PP including PP-B, PP-H, PP-R; - PE; - PVDF; - ECTFE; - FEP; - PFA. This document is not concerned with the search for the possible influence of these defects on the behaviour of joints in relation to the different types of stress to which the latter may be subjected or on method for preventing such defects. It cannot therefore be used for the acceptance of welds which is defined in quality level standards (see [1]). Only defects giving rise to discontinuities of materials or changes in shape are taken into consideration in this document, specifying their type, their shape and their positions, without however always indicating their origin or their causes.