CC-1000_2018

Soil Gas Control Systems ANSI/AARST CC-1000 2018 in New Construction of Buildings 7 Informative note— These aggregates contain a high percentage of nominally 3/4-inch (19mm) stone with less than 5% fines; or b) A void space that allows unabated air movement across the entire soil gas collection plenum such as under plastic membranes placed over open soil in crawl spaces or engineered voids under concrete; or c) Sand, fine gravel and soils if permitted and with systems configured in accordance with Section 5.5.3 . 5.5.3 Sand, fine gravel and soils Materials as specified in Table 5.5.3 shall be permitted when all of the following design features are provided: a) A uniform layer of the aggregate not less than 4 inches (10 cm) in depth is provided or exists; b) Main trunk, secondary trunk or branch ducting, such as within geotextile drainage matting or perforated pipe are placed within the gas permeable layer at distances no greater than 20 feet (6 m) apart. When using perforated piping, the piping shall be placed in a trench backfilled with clean aggregate meeting the criteria of Section 5.5.2.a surrounding the pipe on at least 2 sides. The cross-sectional area of the aggregate and pipe soil gas collector shall be at least 50 square inches (323 cm 2 ); c) Inlets into the ducting are to be no closer than 12 inches (30 cm] and no further away than 10 feet (3 m) from foundation walls or other surfaces that represent the sides of the soil gas collection plenum; and d) The configuration or duct network shall provide no less than 1.0 in 2 /ft (21 cm 2 /m) of unobstructed inlet openings to aggregate in a continuous manner across the length of perforated pipe or face of geotextile drainage matting. Table 5.5.3 Alternative gas permeable layer requirements Options Allowed If Including Required System Design Features Restricted Use Example Of Required Design Features Smaller Stone Option This option shall be in accordance with size numbers 467, 67, 7 and 8 as classified by ASTM C33. Informative note— These aggregates contain a high percentage of nominally 3/8-inch (9.5 mm) stone. Example: 3800 sq ft (383 m 2 ) Sand Option This option shall be in accordance with size number 9 as classified by ASTM C33. Informative note— These aggregates contain a high percentage of nominally 0.2 inch (4.75 mm) to 0.1 inch (2 mm) granules. Not permitted for fine sands, silt and clay with more than 10% of the aggregate < 0.05 inch (1 mm). Soil Option This option shall be native soil existing at the building location with uniform characteristics for fragmental aggregate. The native soil shall consist of too little fine earth to fill interstices larger than 1 mm between stones, cobbles, gravel and very coarse sand particles after compaction occurs. Not permitted when containing more than 35% of sand, rock fragment fines, clay and silt. Not permitted when containing more than 10% high plasticity clay or silt (e.g., expansive soil with a liquid limit ≥ 50%)