SGM-SF_2017with 12/20 Revisions

ASD (revised 12/20) 12 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes b) adequate isolation cannot be created between the non-habitable airspace and surrounding airspaces containing one or more atmospherically vented combustion appliances. Resulting configurations shall not induce flue gas spillage described in Section 11.2.2 ; and c) the extent of inaccessible openings between the isolated space and both interior and exterior areas surrounding the isolated space has not been evaluated and accounted for in system design and installation. Regardless if creation of access is needed or if extensive efforts are required to seal or further partition the isolated airspace, the resulting system shall not cause the structure to become unsafe or adversely affect the performance of the building to include: a) Adverse impacts to building systems (with the most notable being flue gas spillage from atmospherically vented combustion appliances located elsewhere in the building); and b) Excessive energy penalties and damage to building components (with the most notable being hot, cold and humid outside air drawn into a non-habitable airspace by the mitigation system). Note—Sub-membrane depressurization (SMD) for open earth crawl spaces is a preferred mitigation method to minimize energy penalties and damage to building components, even if access needs to be created. 6.1.4.4 Safety Requirements ( non-habitable airspaces ) Where entry into a non-habitable air space being depressurized might occur in the future for maintenance or other reason, precautionary safety features are required to prevent exposures to excessive radon or chemical vapor exposure that can result within the depressurized airspace. Safety features shall include: a) Access ports to non-habitable air spaces shall be labeled in accordance with Section 8.4.6 c to provide warning and instructions, such as for ventilating the airspace prior entry or, as warranted, other precautions and instructions; b) Doors and access port hatches that can be opened without the use of tools shall be provided hardware to facilitate adding a lock to prevent incidental entry; and c) Fan monitors required in accordance with Section 8.2 shall be located where they can be accessed without entering the depressurized non-habitable air space. 6.1.5 Block walls 6.1.5.1 Suction Pipe Locations Note—Suction pipe locations for Block Wall Depressurization will depend on the configuration of the hollow void network(s) within walls to be depressurized and the ability to close openings that surround the void network(s). 6.1.5.2 Sealing (block walls) For Block Wall Depressurization , all accessible openings and gaps in the wall that surround the hollow void network being depressurized shall be closed in accordance with Section 7.4.1 to resist air movement between the depressurized void network and both indoor and outdoor air. Informative advisory —If the top or wall surfaces of the void network cannot be closed to resist air entry into the voids, depressurization of the block wall(s) may not be possible. Where openings are not accessible, closure of voids in a course of blocks below the inaccessible openings at a location above outside grade should be considered to isolate a smaller void network for depressurization . Block Walls Pipe to Fan