SGM-SF_2017with 12/20 Revisions

Building Investigations Prior to Design 6 ANSI/AARST SGM-SF 2017 (with 1220 revisions) Soil Gas Mitigation Standards for Existing Homes 5.4 Nondestructive Investigation An investigation of the building structure(s) shall be conducted by a qualified radon or soil gas mitigation professional prior to initiating mitigation work. Note—The investigation is intended to identify any specific building characteristics and configurations that may affect the design, installation and effectiveness of a mitigation system. 5.4.1 Document review Note—The contractor should review all available construction drawings and other information regarding the building that might be of value in determining the mitigation strategy. 5.4.2 Create diagrams A floor plan diagramor series of diagrams shall be developed for retention in quality control records or as provided to a client and should be complemented with photographic documentation of areas of the building to be mitigated. 5.4.3 Visually inspect the building A visual inspection shall be conducted to help identify any specific building characteristics, hazards and configurations that may affect the design, installation and effectiveness of a mitigation system. Note—Examples include: a) significant slab openings, crawlspaces, adjoining slabs, slab floor and exterior wall integrity, and potential footing locations; b) the design nature of heating, ventilation and cooling (HVAC) systems that may cause significant building depressurization or have ducting in contact with the soil; c) identification of fire-rated assemblies or separation required (including for fire-rated party walls between different occupied spaces and fire-rated floor assemblies); and d) identification of general safety concerns that may warrant precautions for worker or occupant health as described in Section 11.2 . 5.4.3.1 The contractor shall provide timely documented notice to the client for conditions found that present safety concerns or unexpected challenges to envisioned mitigation designs. 5.4.4 Design diagram The design plan of the proposed layout of the mitigation system shall be annotated on a diagram to include components of the mitigation system, such as active soil depressurization (ASD) fans, piping and suction points . 5.5 Diagnostic investigation Informative advisory — Diagnostic procedures are recommended and sometimes required to enable appropriate and effective system design. Section 13.2 stipulates required ASD diagnostics when the purpose of the mitigation is for chemical vapor intrusion. Note— Diagnostic procedures chosen will depend upon the level of complexity for identifying or characterizing conditions under, beside and within buildings to adequately project the effects of various system designs. Diagnostic investigation can include one or multiple procedures such as: sub-slab pressure field extension (PFE) tests or analysis; visual assessment(s); characterization of pressure or air exchange rates between indoors and outdoors and also between floors or adjoining air spaces; and diagnostic radon measurements or other contaminant measurements at locations of interest (e.g., mechanical spaces, groundwater and spaces not in ground contact). 5.5.1 ASD designs Informative advisory —For design of ASD systems, it is recommended and sometimes required to conduct a PFE Analysis . PFE Analysis is a set of commonly needed diagnostic techniques to aid design and optimization of soil depressurization systems. Procedures are: a) PFE testing needs to be conducted under closed-building and normal operating conditions for the building. b) Qualitative evidence is sought to identify the distance potential of PFE across the soil gas collection plenum (e.g., airspace under slabs or soil gas retarder). Measurements are made and recorded at a point distant from each suction point to verify intended design. c) Quantitative measurements are also employed for analytical determination of: