PE-X & Other Pipes
Plastic Pipes Conference Association # 1998 Gothenburg
Gill, Knapp, W.Bradley, L.Bradley
The objectives of this research are to better understand the degradation of cross-linked polyethylene (PEX) tubing subjected to pressurized, hot chlorinated water in flow-through systems (like home plumbing) and to estimate its service lifetime. PEX tubing was subjected to pressure testing with flowing hot, chlorinated water at elevated temperatures from 90 ' C to 120 O C . with chlorine levels between 0 and 5 ppm. The combined effects of free chlorine, pH, and metal ion content on the time-tofailure were found to better correlate with the oxidation-reduction potential (ORP) than with the free chlorine content directly. Consumption of the antioxidant was analyzed using the oxidation-induction time (OIT) as a function of fraction of the time-to-failure in the tests, with the antioxidant being fouild to be completely consumed in less than half of the time-to-failure at 115 O C . Fractographic observations made using a scanning electron microscope (SEM) indicated no degradation until the antioxidant was completely consumed. The mechanical integrity of the pipe at failure in the tests. which was always by leakage, was evaluated using burst tests. The nature of the damage at failure was investigated using highly polished cross-sections of pipe which failured by a pin hole leak.
Related papers
Author(s) : Randall J. Knapp
The U.S. Department of Transportation (DOT) through the Pipeline and Hazardous Materials Safety Administration (PHMSA) promulgates Title 49 Code of Federal Regulations. Part 192 establishes the minimum federal safety standards for the transportation of natural or other gas by pipelines in the U.S. On Nov. 20, 2018...
Author(s) : Randall J. Knapp
The “Pipeline Inspection, Protection, Enforcement and Safety Act of 2006” required the Department of Transportation (DOT) to establish a regulation prescribing standards for integrity management programs for distribution pipeline operators. The Pipeline and Hazardous Materials Safety Administration (PHMSA) published...
Author(s) : Bradley, Slay, Self, Register, Lamborn
The crack growth rate in HMN 5202 and HXM 50100 polyethylcne has bcen studied as a function of stress intensity using deeply notched three-point bend specimens. l'he load-line displacen~entin response to a static applied load has been measured, with tlie material compliance as a function of time determined from the...
Author(s) : Morris, Gill
The introduction of a new grade of polyethylene for pressure pipes has presented a challenge to the UK Water Industry. Some aspects of the performance of the pipe itself are claimed to be significantly better than those of existing MDPE grades which would offer significant economic and operational benefits. However,...
Author(s) : Stephens, Gill
Due to its link with the Water Industry WRC has been involved with uPVC pipes for many years. Rased on information gathered from several WRC exercises involving detailed evaluation of operational data, research into pipe failures and information from other suitable sources this paper discusses various aspects found by...
Author(s) : Gill, Law
The pricipal plastics materials used for the distribution of potable water supplies in this comtry are uPVC and polythene. uPVC is now available in pipe sizes up to 24 in. and its use in the UK has increased rapidly since the first pipe of this material was laid in 1958. Polythene pipes have been used for rather...
Members of the Association
