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Chlorine resistance and durability examined
The Plastics Pipe Institute Inc. (PPI) announced that an analysis has been completed on the potential effects of disinfectants on potable water supply polyethylene (PE) pipe. The findings are now available to the industry in a report posted online.
Commissioned by the PPI and The Alliance for PE Pipe, the study, conducted by Jana Laboratories, examines the various areas of a potable water system including chlorination, durability, oxidative aggressiveness, temperature and pressure/stress. Case studies of actual systems encompassing a range of operating conditions, scope of service and system life were also included. Ontario, Canada-based Jana Laboratories is a world-recognized authority on testing and evaluating the effects of disinfectants on pipe materials, according to PPI.
"The base resin in a PE pipe formulation is highly engineered to provide the balance of properties required by the end-use application," said Tony Radoszewski, executive director of the PPI. "This latest study helps to answer the question, 'How will PE pipe perform in my utility?' and identifies the areas that should be addressed during an evaluation. It will also help a utility manager or a water system design engineer respond to questions about the longevity of PE pipe."
Radoszewski explained the background behind the Jana study and the significance of this PPI initiative for the industry.
"Polyethylene pipe materials have been successfully used in potable water applications for more than 50 years and enjoy a consistently high satisfaction rating from water utilities,” he said. “During this time, there has been a continual evolution in PE resins and their performance in pipe systems. To demonstrate and validate the long-term performance of these resins, the industry has been working for more than 10 years to develop accelerated test and analysis methodologies that will help project long term performance in specific end-use environments. This report is a result of that effort.
"Current models project that high performance PE piping materials can, conservatively, provide more than 100 years of resistance to chlorine and chloramine treated potable water through the vast majority of potable water systems when properly designed and installed."
The report, which can be found directly at http://www.janalab.com/pdf/disinfection.pdf, contains case study examples, charts, figures, photographs and other illustrations. It also provides a summary of the efforts; details the mechanisms of long-term aging of PE materials in potable water applications, examines the primary end-use and product factors impacting the long-term aging mechanisms, reports on the methodology to project long-term performance of PE piping materials in potable water applications, validates the methodology and provides the resulting performance projections based on the currently available data.
"The methodology we used for forecasting long-term aging shows that performance is a function of the water quality, water temperature and operating stress, all of which will vary by utility," said Ken Oliphant, Ph.D., P.Eng, executive vice president of Jana Laboratories Inc. "Overall, the methodology developed to project PE pipe performance shows that current generation materials are
expected to have excellent longevity across the majority of end-use applications and good performance even in very aggressive end-use environments."