Wirsbo hePEX is PEX tubing with an oxygen diffusion barrier for radiant heating/cooling and snow melting applications. Wirsbo hePEX is manufactured by Uponor. The tubing meets ASTM F876 and F877 and is listed to ANSI/NSF Standards 14 and 61 for potable plumbing applications as well. The tubing is rated by the PPI for 200°F at 80 psi, 180°F at 100 psi, and 73.4°F at 160 psi. The oxygen diffusion barrier meets DIN 4726.