RMS-LB 2018 with 12/20 Revisions

Sealing (revised 12/20) 31 ANSI/AARST RMS-LB 2018 (with 1220 revisions) Radon Mitigation Standards for Schools and Large Buildings 7.3.1 Perimeter channel drains Accessible gaps to soil at perimeter channel drains and foundation drainage boards shall be closed or sealed to the extent practical without compromising water control capability of the perimeter drainage system. Where sealing perimeter channel drain gaps, methods shall employ materials that will achieve closure yet retain flexibility to allow natural movement of foundation slabs and walls. 7.4 Other Openings to Soil Other accessible and significant openings to soil in slabs or walls shall be sealed to resist air movement between soil and indoor air, such as: at support posts; electrical conduits that are open to soil; and openings for plumbing fixtures under bathtubs. 7.4.1 Block walls Where Block Wall Depressurization is installed, all accessible openings and gaps in hollow block masonry walls that surround the hollow void network being depressurized shall be closed to resist air movement between the depressurized void network and both indoor air and outdoor air. Closure shall result in resisting migration of air into the depressurized void network, to include: a) open blocks at the top course of hollow block masonry walls and open blocks under door or window openings; and b) cracks or openings in the block walls, both inside and outside of the building. Materials used to close openings and gaps shall be in accordance with Sections 7.2.3, 7.2.4 or equivalent. 7.4.2 Basement de-watering systems If an ASD suction point must be installed into a basement de-watering system, exposed openings into the drainage system that can be sealed without compromising water drainage features shall be sealed, to include as required in Section 7.3.1 . Informative advisory—The vacuum extension needed under a slab will often not occur if the suction point is drawing most of its air from nearby openings in the slab. The suction point location compared to nearby openings in a slab must be considered for achieving mitigation system goals. Consistent with this concern, it is best to close any exposed block wall foundation openings that are above the floor adjacent to a depressurized de-watering system. 7.5 Sumps and Pits Sumps or other accessible pit openings in the interior slab(s) that connect to soil air shall be covered and sealed to the extent possible without compromising the water control capability of the sump . The manner of closure shall also not compromise safety concerns, such as emergency pressure relief discharge from hydronic heating system water boilers. Covers are not required for pits that do not connect to soil air. 7.5.1 Sump cover specifications Sumps in interior floors that connect to soil air shall have a rigid lid made of sturdy and durable plastic such as polycarbonate plastic or other rot-resistant, rigid material sufficient to support anticipated loads in the area of use. The lid shall be mechanically fastened in a manner to facilitate removal for maintenance. The lid shall be sealed to resist air movement between soil gas and indoor air with a gasket or with nonpermanent caulk such as silicone. Penetrations through the lid such as gaps around electrical wiring, water ejection pipes and ASD piping shall be sealed. 7.5.1.1 Access Sump covers shall include a removable port or section of the lid no less than 4 inches (10 cm) in diameter or equivalent method when a sump pump is installed in the pit to allow physical access for routine verification that pumps are operational.