PERT pipe with an EVOH (Ethylene Vinyl Alcohol) layer is a specialized tube designed for closed-loop hydronic heating systems. While retaining the core benefits of standard PERT—excellent flexibility and high-temperature resistance—it adds a crucial co-extruded outer layer. This EVOH barrier prevents oxygen from permeating the pipe and dissolving into the system's water. This protection is vital for preventing the rust and corrosion of ferrous components like boilers, pumps, and radiators, ensuring system longevity and efficiency.