SGM-SF_2017with 12/20 Revisions

ASD (revised 12/20) 19 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 6.4 ASD Exhaust Discharge 6.4.1 General 6.4.1.1 Measuring Distances Distances shall be measured between the closest point of the exhaust opening to the closest point of all location requirements specified in Section 6.4 using the shortest distance, as if a string were stretched between them. 6.4.1.2 Definitions Definitions a), b), c) and d) of this Section 6.4.1.2 shall apply to exhaust requirements in Section 6.4 : a) Openings in structure The openings created in structural walls or roofs for the purpose of mounting windows, skylights, doors or other assemblies that might open to outdoor air; b) Operable openings The operable or constantly open portion of windows, skylights, doors and other openings designed to readily operate for increasing ventilation with outdoor air; c) Exhaust trajectory The angle of the pipe or elbow at the point of exhaust . The angle of the exhaust trajectory from the open end of the pipe or elbow is geometrically defined as the straight- or center-line axis that extends outward from the geometric center of the exhaust opening and is perpendicular to the plane of the exhaust opening; and d) Exhaust spread The exhaust spread extends outward from the point of exhaust in the shape of a circular cone. The tip or apex of the cone is at the geometric center of the exhaust opening and the cone profile grows larger as distance from the point of exhaust increases. Note—The total directional spread of the exhaust or cone is defined in degrees by the offset-axis angle of the cone profile compared to the cone's center-line axis. Expanding outward from the point of exhaust : — An exhaust spread radius of 45˚ equals an exhaust spread diameter of 90˚. — An exhaust spread radius of 11˚ equals an exhaust spread diameter of 22˚. 6.4.2 Outdoors The point of exhaust for all soil gas vent systems shall be located outdoors. 6.4.3 Directional spread (restrictions) The exhaust trajectory with an exhaust spread radius of 45˚ shall not encounter openings in any structures, building materials or the breathing space where individuals congregate or traverse within 10 feet (3 m) from the point of exhaust . Exception: Composite or otherwise layered water-tight roofing materials. 6.4.4 Straight-line trajectory (restrictions) The straight-line exhaust trajectory with an exhaust spread radius of 11˚ shall not encounter openings in any structures, attic ventilation openings, building materials or the breathing space where individuals congregate or traverse within 20 feet (6 m) from the point of exhaust .