An accelerated method for establishing the long term performance of polyethylene gas pipe materials

Abstract

Abstract It was demonstrated in a previous investigation that both horizontal and vertical shifting is required to produce master curves for the relaxation moduli from elevated temperature data for polyethylene gas pipe materials. In this study, the shift functions obtained from these stress relaxation tests are applied to an assortment of elevated temperature time‐dependent failure data for a variety of medium and high density polyethylenes. In all cases the data are successfully shifted to produce coherent master curves within the intrinsic scatter of the original data sets. The implication is that these horizontal and vertical shift functions are, for all practical purposes, universal for polyethylene gas pipe materials. This finding provides the basis for interpreting elevated temperature test data for polyethylene pipe materials so that a substantial savings in cost and time may be achieved in assessing the performance, structural integrity, and life expectancy of piping systems made from these materials.