A new standard evaluates the possible effects of chlorinated water on PEX (crosslinked polyethylene) piping. F 2023, Standard Test Method for Evaluating the Oxidative Resistance of PEX Thermoplastic Piping is now available from ASTM. Approved in June, F 2023 was devised by a task group of Subcommittee F17.40 on Test Methods in Committee F17 on Plastic Piping Systems.

By performing the evaluation in F 2023, PEX suppliers can measure and compare various formulations and assess future modifications, says Task Group Chairman Stephen Pregun, a consultant with Pregun’s Polymer Services, Houston, Texas, and a 40-year plastics industry veteran formerly with Shell Chemical. “The results obtained from the test method will provide a reference index so that materials can be compared under similar, extremely aggressive test conditions that exceed those conditions typically found in U.S. plumbing systems,” he notes.

“Over the past 20 years there has been considerable debate over the suitability of plastic pipe for use in potable water plumbing systems,” he explains. “In particular the long term performance of polyolefin piping was questioned. This standard was developed specifically to provide a method whereby pipe utilizing PEX could be evaluated under extremely aggressive conditions.

“PEX piping is currently most widely used in a variety of water applications in North America, Europe, and Asia,” continues Pregun, who has developed plastic piping standards with ASTM for 35 years. “The major use would be in potable water plumbing systems containing chlorine levels usually between 0.4 and 2.0 parts per million of chlorine operating at temperatures of 150 degrees F or below. Another significant and long-established use is in underfloor heating applications where long lengths of pipe can be coiled, minimizing the need for joints.”

PEX is also being considered for use in residential fire-sprinkler systems.

Technical questions may be directed to Stephen Pregun, Pregun’s Polymer Services, 5711 Sugar Hill #39, Houston, TX 77057(phone/fax: 713/ 782-2898). Committee F17 meets Nov. 13-16 in Orlando, Fla. For meeting or membership information, contact Staff Manager Pat Picariello, ASTM (610/832-9720). //

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