Marketing InformationDischarge from the relief valve shall be piped full size separately to the outside of the building or to an indirect waste receptor inside the building. In areas subject to freezing, the relief valve shall discharge through an air gap into an indirect waste receptor located within the heated space or by other approved means. In addition to all other requirements, if the relief outlet discharge piping is installed so that it leaves the room or enclosure in which the water heater and relief valve are located and discharges to an indirect waste receptor, there shall be an air gap installed before or at the point of leaving the room or enclosure.