Vibien, Couch, Oliphant, Zhou, Zhang, Chudnovsky
# 2001 Munich
The chlorine present in potable water as a disinfectant has been reported to reduce the lifetime of some plumbing system components. In this study the nature of the failure mechanism of a commercial cross-linked polyethylene (PEX) pipe material exposed in the laboratory to chlorinated potable water is examined. The observed failure mechanism for laboratory tested PEX pipe materials is seen to be similar to the failure mechanism observed for field failures of polybutylene (PB) pipe materials, indicating that laboratory testing can replicate potential failure mechanisms in service. Water quality, or more specifically, chlorine level, is seen to have a significant impact on material performance. Test lifetimes are seen to be noticeably lower for chlorinated potable water, even at chlorine levels as low as 0.1 mg/ L (ppm), than for non-chlorinated water. Through accelerated testing at multiple temperature and pressure conditions and the use of the Rate Process Model, a model to estimate the test lifetime of the PEX pipe material at end use conditions is developed. Based on this analysis the PEX pipe material examined in this study appears to have good resistance to chlorinated potable water. The extension of this testing methodology to other materials and water qualities is discussed.
