SGM-SF_2017with 12/20 Revisions

ASD (revised 12/20) 21 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 6.4.8 Equipment Wells and Parapet roofs The point of exhaust relative to open equipment well airspaces or parapet roof construction, where areas are enclosed by more than two walls, shall comply with Section 6.4.3 Directional spread , to include the breathing space where individuals conduct maintenance. 6.4.9 Angled Trajectories The point of exhaust shall be directed upward without obstruction at an angle that does not deviate more than 45 degrees from a vertical exhaust trajectory. The exhaust discharge shall not exhaust downward. Exceptions: 90 degree horizontal exhausts shall comply with requirements in Section 6.4.12 6 .4.10 Roof The point of exhaust shall comply with Section 6.4.3 Directional spread and, unless all requirements of Section 6.4.11 are met, the point of exhaust shall be: a) not less than 1 foot (30 cm) above a pitched roof at the point penetrated; b) not less than 6 inches (15 cm) above the edge of the roof when ASD piping is attached to the side of a building; and c) not less than 18 inches (46 cm) above a flat roof. 6.4.11 Below the roof The point of exhaust shall be permitted to be located below the edge of the roof if the configuration complies with all other requirements of Section 6.4 and all of the following requirements are met: a) The justification for not locating the exhaust above the edge of the roof shall be recorded in the operations and maintenance plan and shall be based upon either: 1. the inability to comply with other requirements of Section 6.4 if the point of exhaust were located above the roof, or 2. the edge of the roof exceeds 20 feet (6m) above grade nearest to the point of exhaust ; b) The point of exhaust shall be not less than 20 feet (6m) above grade nearest to the point of exhaust ; and c) Testing shall be conducted within the occupiable area that immediately adjoins the 45˚ Directional spread required in Section 6.4.3. This testing is required no later than in conjunction with the initial post- mitigation test and shall be recommended for inclusion in all future post- mitigation tests. Informative advisory —Where time constraints allow, long-term testing subsequent to an initial short-term test is recommended.