Doug Seargeant, P. Eng.
Papers # 2014 Chicago
Many utilities experience problems related to corrosion of buried metallic components of their water distribution systems. In seeking non-metallic alternatives to solve these problems, questions concerning the life expectancy of these alternatives are often raised. This paper describes testing of Poly Vinyl Chloride (PVC) pipe material after being in service for more than 25 years in Edmonton. The first use of PVC water main pipe manufactured to AWWA C900 in the City of Edmonton occurred in 1977. The increasing rate of water main failure in the cast iron water main material used previously in the distribution system led the water utility to seek a non-metallic alternative. This initial installation in 1977 quickly led to PVC becoming the material of choice for water distribution piping used for replacement of the deteriorating cast iron piping system as well as for installations in newly developing areas of the city. By the end of 2013, the length of PVC pipe in the City of Edmonton water distribution system was over 1, 600 kilometres (1,000 miles) representing 47% of the total length of pipe in the water distribution system. In 1994, a study was undertaken to review the City of Edmonton’s experience with respect to the performance of PVC pipe over time and to assess the integrity of material which had been in service for 17 years. In 2005, the decision was made to revisit the methodology used in the 1994 study and look at PVC pipe that had been in service for at least 25 years. This paper summarizes the findings in those studies and provides additional information on EPCOR’s water distribution system in Edmonton.