This document provides quality levels for imperfections in thermoplastics welded joints. It applies to material thickness above 2,0 mm. Three quality levels are given in order to permit application for a wide range of welded fabrication. They are designated by symbols B, C and D, where B is the most stringent. The quality levels refer to production quality and not to the fitness-for-purpose (see 3.2) of the manufactured product. This document applies to the following thermoplastic materials in Table 1: Table 1 Thermoplastic materials Abbreviation Material description ABS Acrylonitrile-butadiene-styrene plastic ECTFE Ethylene-chlorotrifluoroethylene copolymer FEP Fluorinated ethylene propylene PA-U Unplasticized Polyamide PB Polybutylene PE Polyethylene PFA Perfluoroalkoxy PP-B Polypropylene block copolymer PP-H Polypropylene homopolymer PP-R Polypropylene random copolymer PVC-C Chlorinated polyvinyl chloride PVC-U Unplasticized polyvinyl chloride (rigid PVC) PVDF Polyvinylidene fluoride and to the following welding processes: heated tool welding; electrofusion welding; hot gas welding using filler rod only; extrusion welding; solvent welding of pipes.