CCAH-2020

Reducing Radon in New Construction of ANSI/AARST CCAH 2020 1 & 2 Family Dwellings and Townhouses 8 SECTION 403 SUB - SLAB SOIL GAS COLLECTION PLENUMS 403.1 Concrete floors. The floors of basement, concrete crawl space and slab-on-grade foundation systems shall be provided with a soil gas collection plenum installed in accordance with Sections 403.1.1 through 404.1.6. 403.1.1 Soil gas collector. A soil gas collector shall be installed in accordance with Section 403.1.1.1, 403.1.1.2,403.1.1.3 or 403.1.1.4. 403.1.1.1 Gravel. A uniform layer of clean aggregate, not less than 4 inches [10 cm] in depth, shall be placed over the soil. The aggregate shall have a void ratio of not less than 35 percent or shall be Size Number 4, 5, 56, 57, or 6 as classified by ASTM C33. 403.1.1.2 Geotextile. A layer of geotextile drainage matting shall be placed over a uniform layer of either soil or sand. The geotextile drainage matting shall be designed to allow the lateral flow of soil gases to the system’s suction point fitting. The geotextile matting shall have a cross-sectional area of not less than 12 square inches [77 sq. cm] and shall be placed along the entire inside perimeter of the foundation at a distance of 12 inches [30 cm] to 18 inches [46 cm] from the foundation wall to the closest edge of the drainage matting. Deviation from the 12 inch [30 cm] to 18 inch [46 cm] distance to the foundation wall shall be allowed only at the location of obstacles such as plumbing and other utilities. 403.1.1.3 Pipe loop. A loop of 4 inch [10 cm] minimumdiameter perforated pipe shall be placed along the entire inside perimeter of the foundation at a distance of 12 inches [30 cm] to 18 inches [46 cm] from the centerline of the pipe to the foundation walls. Such piping shall be placed in a trench backfilled with clean aggregate meeting the criteria of Section 403.1.1.1 and surrounding the pipe for at least 1/3 of the outside pipe circumference. The cross-sectional area of the aggregate and pipe soil gas collector shall be at least 50 square inches [323 sq cm]. The piping shall form a continuous loop and pipe sections shall be joined with a connector device/method recommended by the manufacturer. Deviation from the 12 inch [30 cm] to 18 inch [46 cm] distance to the foundation wall shall be allowed to avoid obstacles such as plumbing and other utilities. 403.1.1.4 Foundation form/drain/vent soil gas collector. The soil gas collector shall consist of a loop of interconnected lineals used to cast the foundation footing and left in place to provide ground water control and provide a separate channel above the ground water channel for soil gas ventilation. Said soil gas ventilation channel shall have a cross sectional area no less than 12 square inches [77 sq. cm]. 403.2.2 Suction points. Not less than one suction point shall be provided for each foundation type and not less than one suction point shall be provided for each soil gas collector. Alternatively, each soil gas collector shall be interconnected by a pipe loop soil gas collector that is constructed in accordance with Section 403.2.3 and served by one or more suction points . During construction, suction point openings above the slab shall be protected from the entry of aggregate, concrete and debris. Suction points shall be installed in accordance with Section 403.2.2.1, 403.2.2.2 or 403.2.2.3 as applicable for the type of soil gas collector installed.