Pre-insulated Wirsbo® hePEX™ features oxygen-barrier PEX pipe encased in polyethylene-foam insulation to meet ASHRAE 90.1-2013 energy-code requirements for hydronic piping and radiant heating/cooling applications. The piping is approved for direct burial in soil provided it is not exposed to groundwater. Uponor recommends adding 1/2 in of insulation to accommodate for foam compression in direct-burial applications.