Oertli, Ifwarson
# 2001 Munich
While guaranteed lifetimes of pressure pipes in use is roughly 50 years, it is commonly accepted that a well designed and manufactured HDPE/MDPE pressure pipe would last as long as 100 years without failures. With ever-growing world population and intensifying pollution, it has become increasingly difficult supplying people with their daily demand for adequately pure drinking water. Water-works in many regions of the world cannot depend of filtration methods alone for preparing a flawless water quality but must adhere to chlorination for dealing with germs and microorganisms. In extended studies related to the influence of chlorinated water on the lifetime expectation of pressure pipes conducted over the last 7 years it has become evident, that even a very small concentration of chlorine in the water can have a detrimental effect on the lifetime expectancy of pressure pipes. Pipe exposed to non-chlorinated water show longer lifetimes estimated to be 10-30 times longer than the same pipes exposed to chlorinated water. In an attempt to better understand the reason for such early failures under laboratory conditions and finding novel additive formulations, various pipe formulations were tested under severe chlorine conditions. It was found that the lifetime prediction for pressure pipes strongly depends on the formulation.
