DIN 16961


DIN 16961 Thermoplastics pipes and fittings with profiled outer and smooth inner surfaces:

Part 1: Dimensions

Part 2: Technical delivery conditions

The first part of this German standard sets the dimensions and properties for thermoplastic pipes with profiled outer and smooth inner surfaces. The second part focuses on technical properties for profiled pipes made of PE-HD (high density polyethylene), PVC-U (unplasticized polyvinyl chloride), PP (polypropylene) homopolymers or copolymers. Among other issues the standard sets the methodic for both measuring and calculating ring stiffness of such pipes.
For the purposes of this standard profiled pipes are those with profiled outside surfaces, flanged pipes, helically wound pipes and pipes with foamed inserts in their walls.
The methodic for ring stiffness determination according to DIN 16961 differs completely from the method set by ISO 9969. DIN 16961 takes into account among other parameters the elastic modulus of the material used, the change in test pieces’ internal diameter during the test (measurements in 1 hour, 6 hours and 24 hours after the start of the experiment) due to the constant force applied on the test piece surface.
Today the DIN 16961 is the only standard available EU covering pipes with diameters over DN 1200, more specifically out of scope of the EN 13476 (the application range of EN 13476 is DN 100 – DN 1200). That is why most of the large diameter pipe producers use DIN 16961 for classification of their pipes over DN 1200.