Abstract: | The fatigue resistance of 6 inch Schedule 40 PVC solvent-bonded pipe fittings was investigated. It has often been assumed that the performance of PVC fittings is comparable to that of the corresponding pipe. The results of this study indicate that the fatigue performance of PVC fittings is much lower than that of the pipe. Several fittings were exposed to a repetitive surge cycle of 90 to 180 psig at a rate of 0.111 hertz. Failures of several tees occurred between 13,000 and 16,000 cycles, much sooner than the predicted lifetime of pipe under these conditions. |