This Technical Specification provides guidance for the minimum content of welding procedure specifications for the following welding processes:— hot gas welding: round nozzle, high speed nozzle, wedge; — extrusion welding; — heated tool welding: butt, socket, wedge; — solvent welding: socket; — electrofusion welding: socket, saddle.This Technical Specification applies to the welding of the following products and semi-finished products made of thermoplastic materials:— sheet; — pipe; — fittings; — lining membrane.