Sometimes referred to as EVOH, Oxygen Barrier PEX tubing is used primarily in radiant floor heating, radiator heating systems, and snow melting applications. This variety of PEX is coated with an oxygen barrier to prevent oxygen from leaving or entering the tube thus stopping corrosion of sensitive components in the system. Nations WareHouse offers type B oxygen barrier tubing compliant with the following standards: ASTM F876/F877, CSA B137.5, DIN 4726, NSF 14, SDR 9.