SGM-SF_2017with 12/20 Revisions

Non-ASD Methods 45 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes Note—Floor drains to the sanitary sewer system or other foundation drain systems are recommended for meeting this need. HRV and ERV systems often condensate a continuous flow of water during certain seasons. Informative advisory Economizer systems, heat recovery ventilators (HRV) and energy recovery ventilators (ERV) — Economizer systems typically include controls that automatically activate dampers on return air ducts for using untampered outside air to reduce the cost of cooling a building. These systems often require modification in order to bring outside air into a building at all times. — HRV units are a commonly preferred tool for adding outdoor air to a dwelling due to energy savings when compared to energy consumption for delivering untempered outside air into a building. — ERV units (similar to HRV) often require modification for bringing outside air into a building at all times. 12.2.5 Important maintenance inspections A regimen of routine inspection shall be recommended in accordance with Section 13.7.2 or as stipulated in an OM&M plan that is in accordance with Table 13.7 to include all filters, exterior intake and exhaust vents, duct balance, controls, and other components. 12.2.6 Passive vents (soil air or indoor air dilution) Informative advisory —See Section 12.13.3 for guidance and additional requirements associated with passive ventilation. 12.3 Indoor Air Pressurization Note—Establishing positive pressure in the airspaces close to soil can, under certain conditions, be effective in stopping soil gas entry. Pressurized buildings or airspaces can in some cases be achieved with permanently installed and continually effective mechanical systems. An air source from upper floors or the building exterior is ducted into a confined airspace with enough air volume provided at a sufficient rate ( cfm ) to result in a positively pressured airspace. When Indoor Air Pressurization is employed: 12.3.1 Capacity (pressurization) Mechanical components, newly installed or augmented, shall result in adequate capacity to constantly deliver the air volume provided at a sufficient rate ( cfm ) needed to overcome leakage in the outer shell of the building, airspace or isolated assembly. Systems shall be configured in a manner that can produce consistent positive pressure within the airspace being pressurized. 12.3.2 Sources for air Sources for air delivered to the airspace being pressurized shall comply with Section 12.2 . 12.3.3 Sealing (pressurization) The building or airspace(s) being pressurized shall be augmented as needed to result in a permanently sealed isolation assembly in accordance with Section 7.9 . Exception: Access doorways for the building or airspace being pressurized are not required to be gasketed. However, a mechanical means to automatically achieve positive closure of doors subsequent to entry and exit shall be provided. 12.3.4 Unintentional radon transport For systems applied to portions of the building or an airspace rather than the entire building, considerations shall be made during design with attempts to verify after installation that radon is not transported to another portion of the building by the pressurization system. Considerations are to include the potential for systems to inadvertently drive radon under the building or through partitions into adjoining areas located laterally or vertically from the pressurized airspace. Airspaces or occupiable areas adjoining laterally or vertically to the pressurized area shall be tested for radon during either diagnostic procedures or after installation.