WaterPEX tubing is a cross-linked polyethylene tubing used for potable water applications. WaterPEX is manufactured without an oxygen barrier. Maximum working pressure: 160 psi (pounds per square inch) (11 bar) at 73.4 F (degree Fahrenheit) (23 C degree Celsius), 100 psi (6.9 bar) at 180 F (80 C), 80 psi (5.5 bar) at 200 F (93 C). Watts WaterPEX is manufactured in accordance with ASTM (American Society for Testing and Materials) F-876 and F-877 to SDR-9 (Standard Dimension Standards) 14 and 61 for use in potable water systems. WaterPEX is listed by NSF (National Sanitation Foundation) to be in compliance with the Uniform Plumbing Code. All WaterPEX is labeled B137.5 which indicates that it is also compliant to the CSA (Canadian Standards Association).