I recently attended the Annual Conference for the Uni-Bell Pipe Association in the US, the largest gathering of PVC pipe and fitting manufacturers in the world. At the conference I met with Dr Steven Folkman who recently released a highly detailed, researched and comprehensive study on water main breaks for the US and Canada. His most recent report, Water Main Break Rates In the USA and Canada: A Comprehensive Study April 2012, gave some staggering figures into the cost of corrosion in terms of water quality and failure rates of iron, cement and steel water pipes and the impact and cost of this onto the US and Canadian economy. In our own Australian industry, with many water pipelines being cast or ductile iron and having been in service for 50 years or more in many cases, I would expect these results would be similar in our local market.
The major finding of the study is that PVC pipe has the lowest overall failure rate when compared to cast iron, ductile iron, concrete, steel and asbestos cement pipes. Another major finding concludes corrosion is a major cause of water main breaks: 75% of all utilities have corrosive soil conditions and combined with a high portion of old cast iron and ductile iron pipes, corrosion is ranked the second highest reason for water main pipe failure. When comparing between older cast iron and newer ductile iron, the thinner-walled ductile iron is experiencing failures more rapidly. The study determined that the majority of ductile iron pipe failures occur between 21 and 40 years after installation, whilst concluding that PVC pipes are expected to last for over 110 years.
Dr. Steven Folkman is a registered Professional Engineer, a member of American Society for Testing and Materials (ASTM) F17 Plastic Piping Systems, a member of AWWA and a member of the Transportation Research Board Committee on Culverts and Hydraulic Structures, and has oversight of the prestigious Utah State University's Buried Structures Laboratory (USU - BSL). USU - BSL has been involved in analysis and testing of all kinds of pipe and associated structures for over 50 years and is recognized as one of two laboratories in the U.S for performing large scale tests on buried pipes. Dr. Folkman's expertise includes structural dynamics, linear and nonlinear finite element analysis utilizing soil/structure interaction, and testing.