Methods for determining the in-service life of polymer water pipes

A key requirement for polymer pipes, in having the ability to achieve a long in service life, is the retention by the polymeric material of its anti-oxidants. In dry air and other favourable environmental conditions the life-span of the polymer material can be many decades. However, when polymer pipes are transporting water and the pipes need to be installed in all kinds of ground conditions then the loss of anti-oxidant from the polymer can become more of a problem. To maintain integrity of water distribution networks, companies aim to plan for replacement of water pipes before they are likely to fail. This paper presents ways in which small scale evaluations of aged pipe material can be employed to assess remaining in-service life of water pipes. Small-scale chemical and physical evaluations have been devised to provide indicators of the ageing process with associated loss of mechanical properties. The presented studies were performed using MDPE and PE80 pipe materials. These materials were evaluated before and after ageing to identify which chemical and physical evaluations were the most appropriate to assess the remaining life of in service polymer pipes.