# 2004 Milan
The lifetime of plastic pipes has been studied at Bodycote Polymer AB for more than 30 years. This paper will compare two test methodologies for evaluating multi-layer pipes. An attempt will be made to investigate antioxidant consumption as a function of exposure time for three different PE based multi-layer pipes exposed in a circulation loop, compared with the results from pipes that have been hydrostatically pressure tested. Preliminary lifetime predictions will be made allowing comparison between pipes exposed in a circulation loop and those hydrostatically pressure tested.