CC-1000_2018

Soil Gas Control Systems ANSI/AARST CC-1000 2018 in New Construction of Buildings 11 record of the inspection(s) shall be retained in accordance with Section 12 . Notice : This provision is strongly recommended but not mandatory unless: a) it is required for exercising design options for larger soil gas collection plenums in accorda nce with Sections 4.3.2 and 4.3.3 ; o r b) it is specifically referenced in contract or local ordinance. See Annex A-1 . SECTION 6: CLOSE THE TOP OF THE PLENUM 6.1 General. A continuous sealed barrier is required between the gas permeable layer and the interior of the building to break the air transfer connection between soil and indoor air. The capacity for the closure of concrete floors and soil gas retarders to degrade over time shall be considered when choosing materials and methods for sealing the top of the soil gas collection plenum(s). Considerations shall include: a) building settlement or movement; b) shrinking or cracking of building materials; and c) potential needs to access mechanical systems under floors. 6.2 Closure of concrete floors. Soil gas retarder material shall completely cover the area under the concrete floor and be placed between the gas permeable layer and the concrete slab. The soil gas retarder materials and installation shall be no less than specified in Section 6.4 . Exception: Alternatives to the soil gas retarder are permitted only where ASD fans are installed concurrently with the soil gas vent system and a continuous sealed barrier between soil gas and indoor air is constructed to achieve sustainable closure including requirements of Section 6.2.3 . 6.2.1 Above the soil gas retarder The concrete floors shall be cast directly upon a soil gas retarder with the following exceptions: a) Where sheet foam board insulation or woven geotextile matting is installed under the concrete floor, it is permitted that the soil gas retarder be installed below the foam board insulation or woven matting; and b) A thin layer of fabric or fill material for water drainage or protection of the soil gas retarder is permitted between the soil gas retarder and the concrete floor when the layer is no greater in depth than is required for such purposes. Informative notes — Appropriate considerations include opposing concerns. There can be potential for groundwater above a soil gas retarder to pool and leach into the concrete and cause moisture concerns on the top sides of the slab. Meanwhile, aggregate fills above the soil gas retarder can introduce a radon source not previously present and not addressed herein. 6.2.2 Construction joints in interior concrete floors Permanent closure shall be provided for all concrete joints around the perimeter of each slab and at all expansion or contraction joints by means of: a) gasket materials made of closed cell polyethylene that are manufactured for filling joints and have a tear-off edge strip. These products can retain closure of joints after concrete shrinkage from curing; or b) caulk applied after the concrete cures with caulk that complies with ASTM C920 class 25 or higher or equivalent. The curing period before caulk is applied shall be 28 days unless a qualified concrete or structural professional has verified concrete mixtures allow a shorter curing period; or c) caulk applied prior to the complete curing of concrete if a structural professional verifies that concrete shrinkage is expected to result after curing in joints that are less than 1/8th of an inch (4 mm) in width. The verification calculation shall consider both the concrete mixture and the slab size(s). 6.2.3 Molded or saw-cut control joints In any situation where a soil gas retarder is not placed between the slab and the gas permeable layer, all molded or saw-cut control joints shall be sealed with caulk complying with ASTM C920 class 25 or higher or an equivalent method. 6.2.4 Openings and penetrations Openings and penetrations in the top of all soil gas collection plenums shall be sealed against air leakage to include openings around plumbing, exhaust vent pipes , mechanical piping, structural supports and gaps to the inside of hollow structural posts and electrical conduits that are open to soil. Sealing of the penetration or opening shall be achieved with caulk that complies with ASTM C920 class 25 or higher or equivalent, closed cell gasket materials or an equivalent method. When caulk is used to seal a crack, joint or opening greater than 1/2 inch (13 mm) in width, foam backer rod or other comparable filler material Figure 6.1