SGM-SF_2017with 12/20 Revisions

Non-ASD Methods 44 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 12.1.5 Long-term OM&M plans required All ASD and non- ASD methods applied shall be accompanied with an OM&M Plan in accordance with Section 13.7 that includes all applicable provisions for each method. 12.2 Sources for Air Delivered to a Building Informative advisory —A variety of the options may be present for sources of air (or make-up air) when needed for pressurization or dilution systems. Many of these choices can however have profound adverse effects on energy consumption and occupant comfort or safety. 12.2.1 Capacity (sources of air) System design and installation shall result in a configuration with adequate capacity to continually provide the required volume of air needed to achieve mitigation goals. 12.2.2 Adverse effects Sources for air delivered to the airspace being mitigated shall not result in adverse effects on the building including for: other mechanical systems (i.e., back draft of combustion appliances); other indoor air quality concerns 8 ; unnecessary energy consumption 9 ; and occupant comfort and safety. 12.2.3 Air intake and distribution vents a) Vent Blockage Vents shall be in locations unlikely to be inadvertently blocked by stored or standing items and natural obstructions such as snow or foliage. b) Vent Protection Vents shall be protected at both internal and external locations with vent covers, wire mesh or screening in order to prevent blockage from debris, entry of animals or injury to occupants. c) Intake Vents – Air Quality Intake vents shall be in locations where airborne pollutants (e.g., vehicle emissions, trash containers and combustion appliance emissions) are distant enough from the intake to not enter the building and adversely affect the comfort and safety of occupants. d) Interior Intake Vents - Adverse Effects Intake vent locations within a building shall be located and installed to not adversely affect energy consumption, other building systems including combustion appliances, and occupant comfort and safety. e) Duct Balance Contractors shall verify that the balance of incoming and outgoing airflow does not create a negative pressure within portions of the building in contact with the soil. 12.2.4 Outdoor air systems Requirements for mechanical systems that introduce outdoor air into a building include: a) Protective Capacity Systems shall be configured to constantly deliver the air volume and velocity needed to achieve mitigation goals whenever any portion of the building is occupied , in accordance with Section 12.7 . b) Distances—Supply and Exhaust Ports For HRV and ERV installations, interior supply and exhaust ports shall be located a minimum of 12 feet (3.8 m) apart. The exterior supply and exhaust ports shall be positioned to avoid blockage by snow or leaves and be a minimum of 10 feet (3 m) apart. c) Condensate Drainage Adequate drainage capacity shall be considered in design and provided to accommodate condensate water from systems. 8 For further information, see ANSI/ASHRAE Standard 62.1 “Ventilation for Acceptable Indoor Air Quality” for buildings that are more than three stories tall or ANSI/ASHRAE Standard 62.2 “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings” 9 For further information, see ANSI/ASHRAE/ USGBC/IES 189.1, “Standard for the Design of High-Performance Green Buildings Except Low- Rise Residential Buildings,” or ICC 700, “National Green Building Standard for Residential Construction”.