Pex Piping With Oxygen Barrier
External coating of oxygen barrier PEX tubing effectively prevents diffusion of oxygen molecules into the water through walls of the pipe. This feature prevents corrosion of cast iron components in the system (circulator pumps, air purgers, fill valves, boiler heating elements, etc.)
Most oxygen-barrier PEX does not have the appropriate approval codes for use with potable water and should not be installed in domestic plumbing applications. Since oxygen from the air can penetrate PEX tubing (even when the PEX is embedded in a concrete slab), an oxygen barrier is needed in most heating systems. It often has a shiny gloss to it, compared to non barrier. Rub it together and it will squeak. If you heat it with a match or torch carefully you may see that EVOH layer start to de-laminate from the tube. PEX with an oxygen barrier is designed for closed-loop space heating systems, and will normally be either red or white. It is usually not approved for use with potable water. PEX piping is more durable than copper piping, and it is used in an innumerable number of applications, such as radiant heating systems for residential and industrial plumbing. The average life span of PEX for plumbing purposes goes well over 50 years.