Effect of chlorine on polyethylene pipes in water distribution networks

Abstract

With the increasing worry over water supplies, there is much interest worldwide in measures to be taken to retain the integrity of water distribution networks. This paper reports on a study of the integrity of polyethylene water distribution pipes related to the effect of chlorine in the water. Pipes used in water distribution networks are subject to demanding environmental, functional, and other stresses. Their working lifespan depends much on retention by the material of its antioxidant. In dry air, polyethylene can retain its properties for many decades. However, when polyethylene pipes are used in water distribution networks, the diffusion and loss of antioxidant from the material is increased from the inner pipe surface. When chlorine is present in the water, it can enter and spread through the material to increase the depletion rate of the antioxidant population. In this research, samples of pipe materials and sections of manufactured pipes have been subjected to accelerated life assessments. Also, modelling techniques have been devised to simulate the depletion of antioxidants in the pipe materials and used to research different possibilities including varying the concentrations of aggressive agents.