Understanding brittle failure of uPVC (unplasticised polyvinyl chloride) pipe

Abstract

UPVC pipes are designed to have a 50 year lifetime. Although their performance in service is generally very satisfactory, there have been occasions where premature brittle failure has occurred. It is shown that the effect of processing variations on the yield stress is not great but that processing has dramatic effects on the brittle failure stress. Incomplete gelation of the PVC decreases the brittle failure stress and introduces flaws into the material from which brittle failure can occur. Means of predicting the lifetime to brittle failure for uPVC pipe under static and dynamic pressure are presented. © 1985 IUPAC