Ecoflex thermal twin pipes are designed for fluid transfer in heating and cooling applications. The Wirsbo hePEX service pipes in Ecoflex thermal twin piping are manufactured by the Engel-method (PEX-a) process and are listed to ASTM F876 and F877. An oxygen-diffusion barrier extruded onto the service pipe dramatically reduces the amount of oxygen molecules that can migrate through the tubing wall. This oxygen-diffusion barrier protects ferrous components within the fluid pathway from corrosion. The pipe is surrounded by multi-layer, closed-cell, PEX-foam insulation and a water-resistant, corrugated HDPE jacket, making it ideal for direct-burial applications.