ASTM F3253 – Standard Specification for Crosslinked Polyethylene (PEX) Tubing with Oxygen Barrier for Hot- and Cold-Water Hydronic Distribution Systems

1.1 This specification covers requirements, test methods, and marking requirements for crosslinked polyethylene (PEX) tubing with a polymeric oxygen barrier layer, made in one standard dimension ratio (SDR 9), and distribution system components intended for hydronic heating and cooling applications up to and including a maximum working temperature of 200 °F (93 °C).

1.1.1 Components are comprised of tubing, fittings, valves, and manifolds. Tubing made to this specification incorporates a single outer or middle wall oxygen barrier layer intended for inhibiting the transmission or permeation of oxygen through the tubing wall. Requirements and test methods are included for materials, workmanship, tubing dimensions and tolerances, burst pressure, sustained pressure, excessive temperature and pressure, thermo-cycling, bent tube, oxidative resistance, layer adhesion, UV resistance, oxygen permeation, and fitting pull-out strength tests. The components covered by this specification are intended for use in residential and commercial hydronic heating and cooling systems. Requirements for potable water applications are outside the scope of this specification.