1202.7.3 Radon Prescriptive Requirements
Exception: Aggregate shall not be required if a substitute material or system, with sufficient load-bearing characteristics, and having approved capability to provide equal or superior air flow, is installed.
All penetrations and joints in concrete slabs or other floor systems and walls below grade shall be sealed by an approved sealant to create an air barrier to limit the movement of soil-gas into the indoor air.
Sealants shall be approved by the manufacturer for the intended purpose. Sealant joints shall conform to manufacturer's specifications. The sealant shall be placed and tooled in accordance with manufacturer's specifications. There shall be no gaps or voids after the sealant has cured.
One continuous sealed pipe shall run from a point within the aggregate under each concrete slab to a point outside the building. Joints and connections shall be permanently gas tight. The continuous sealed pipe shall interface with the aggregate in the following manner, or by other approved equal method. The pipe shall be permanently connected to a "T" within the aggregate area so that the two end openings of the "T" lie within the aggregate area. A minimum of 5 feet (1524 mm) of perforated drain pipe of 3 inches (76 mm) minimum diameter shall join to and extend from the "T." The perforated pipe shall remain in the aggregate area and shall not be capped at the ends. The "T" and its perforated pipe extensions shall be located at least 5 feet (1524 mm) horizontally from the exterior perimeter of the aggregate area.
The continuous sealed pipe shall terminate no less than 12 inches (305 mm) above the eave, and more than 10 horizontal feet (3048 mm) from a woodstove or fireplace chimney, or operable window. The continuous sealed pipe shall be labeled "radon vent." The label shall be placed so as to remain visible to an occupant.
The minimum pipe diameter shall be 3 inches (76 mm) unless otherwise approved. Acceptable sealed plastic pipe shall be smooth walled, and may include either PVC schedule 40 or ABS schedule of equivalent wall thickness.
The entire sealed pipe system shall be sloped to drain to the subslab aggregate.
The sealed pipe system may pass through an unconditioned attic before exiting the building; but to the extent practicable, the sealed pipe shall be located inside the thermal envelope of the building in order to enhance passive stack venting.
Exception: A fan for subslab depressurization system includes the following:
If the subslab depressurization system is exhausted through the concrete foundation wall or rim joist, the exhaust terminus shall be a minimum of 6 feet (1829 mm) from operable windows or outdoor air intake vents and shall be directed away from operable windows and outdoor air intake vents to prevent radon reentrainment.
If the 4-inch (102 mm) aggregate area underneath the concrete slab is not continuous, but is separated into distinct isolated aggregate areas by a footing or other barrier, a minimum of one radon vent pipe shall be installed into each separate aggregate area.
Exception: Separate aggregate areas may be considered a single area if a minimum 3-inch (76 mm) diameter connection joining the separate areas is provided for every 30 feet (9144 mm) of barrier separating those areas.