SGM-SF_2017with 12/20 Revisions

ASD (revised 12/20) 13 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 6.2 ASD Piping 6.2.1 Air and water-tight All duct piping and fittings that transport air shall result in being air- and water-tight, except at soil gas intake locations, exhaust locations and fan monitor test ports. 6.2.2 Slope required Above-ground duct piping shall have a continuous downward slope toward the suction point (s) of not less than 1/8 inch (3.2 mm) per foot (30 cm) to allow condensation or rainwater within the pipes to drain downward into the ground beneath the slab or soil-gas retarder membrane. When drainage cannot be achieved, other methods for draining collected water shall be provided. Configurations that result in obstructed airflow as a result of allowing water to collect within duct piping are prohibited. 6.2.3 Positively-pressurized pipe Positively-pressurized ASD duct piping or other positively pressurized components of an ASD system shall not be installed in or pass through or pass under the conditioned space of the building. 6.2.4 Labels required (duct piping) Duct piping shall be labeled in accordance with Section 8.4.4. 6.2.5 ASD pipe materials All ASD duct piping, except piping routed below concrete slabs or under soil gas retarder membranes shall be rigid, non-perforated and meet the following requirements: a) ABS plastic piping shall comply with ASTM D2661, F628 or F1488. Pipe wall thickness shall be Schedule 40 with solid, cellular core or composite wall. ABS pipe joints shall be solvent welded in accordance with the pipe manufacturer’s instructions, with solvent cement conforming to ASTM D 2235. b) PVC plastic piping shall comply with ASTM D2665, F891 or F1488. Pipe wall thickness shall be Schedule 40 with solid, cellular core or composite wall. PVC pipe joints shall be joined in accordance with the pipe manufacturer’s instructions with cement conforming to ASTM D2564. The joint surfaces for PVC plastic pipe and fittings to be solvent welded shall be prepared with: 1. a primer conforming to ASTM F656; or 2. a self-priming product; or 3. as otherwise stipulated in the pipe manufacturer instructions. c) All ASD plastic pipe fittings shall be of the same material as the plastic piping they are joined to and solvent welded unless joined with flexible couplings in accordance with Section 6.2.6 . Figure 6.2.3 Negatively pressured pipe Positively pressured pipe