Handbook Plastic Pipe Ring Stiffness part 3
- Alternative Test Procedures for Ring Stiffness
All Manufacturers of large diameter plastic pipes face the same challenge regarding regular testing of ring stiffness. Especially dimensions bigger than DN 2000 are problematic, because of typical existing infrastructure in laboratories. The weight of the cut pipe lenght and the size it self require special equipment to handle the samples and more that that often bigger laboratories are necessary.
In earlier times thermoplastic pipes did not reach sizes and weights as they do today. Pipe weights of more than 2 ton/m are now realistic. The mentioned practical reasons but also commercial reasons were the beginning for developing an alternative test method for testing pipe stiffness. Furthermore the bigger the pipes the more complicate become the testing of samples by external laboratories and third party control.
Thermoplastic pipes are homogenously manufactured and provide uniform static properties around the circumference and lenght. A cut pipe segment should have same characteristics if the disturbing load differences are considered. A group of large diameter pipe producers made many tests to verify the theoretical assumptions and in the meantime in the Germen DIN 16917 the procedure is described in detail.