T-91-101-R (15.05.97) Long-Term Ring Bending Strain (Sb) – Flowtite Pressure Pipe


The combined loading design method of AWWA M45 requries for a pressure water application that a minimum factor of safety of 1.5 be maintained on a pipe’s long term ring bending capability while submerged in water. ASTM D5365-93 provides the testing guidelines for determining the 50 year ring bending capability of the GRP pipe. This report presents the test data for Flowtite pipe submerged in water with a pH of 4 and 10, and the resulting predicted long term ring bending strain. This report can be used with an end user or consultant as a proof statement supporting the use of a long term ring bending strain of 1.30 % for Flowtite pipe. It also helps demonstrate that the design life of Flowtite pipe is 50 years, where factors of safety (FS=1.5) are applied to the pipe’s 50 year performance limits and not initial.