NSF Special Section-Oxidative Stability Requirements for PEX Pipe
In 2002, ASTM F876, Standard Specification for Cross-linked Polyethylene (PEX) Tubing, was updated to include a requirement for the oxidative stability in potable chlorinated water application. This was based on the test method F2023-03, Standard Test Method for Evaluating the Oxidative Resistance of Cross-linked Polyethylene (PEX) Tubing and Systems to Hot Chlorinated Water.
The standard requires all PEX pipes used in potable water to be evaluated against the ASTM F2023 test method and have a minimum extrapolated test lifetime of 50 years at the end use conditions of 80 psi constant internal gauge pressure with water temperatures at: