SGM-SF_2017with 12/20 Revisions

14 SGM-SF SGM-SF Discussion CG SECTION 13 VAPOR INTRUSION REQUIREMENTS Additional requirements when mitigating chemical vapor intrusion. 13.1 Qualified Professionals and Teams For Mitigation professionals— Informational descriptions are provided for understanding interactions between parties that are more complicated than relationships with a single family. Persons qualified in varied disciplines with different skill sets are usually needed to accomplish reductions in occupant exposures to hazardous chemical vapors, gases and other substances. For Commissioning teams— It is recommended to engage a Qualified Soil Gas Professional at the onset of mitigation discussions. 13.2 Assemble Site Information 13.2.1 Handling and control of hazardous substances and conditions Advisory Example 1— Details associated with evaluating and designing effective ground water control are beyond the scope of this document. A qualified and experienced ground water control specialist should be contracted or consulted when ground water control is needed. Evaluations of this condition normally include review of structural and exterior components that might have failed or are ineffective for ground water control. When grading and roof downspouts do not flow rainwater away from a building, the tremendous weight of water collecting in the soil will drive water below grade to forcefully intrude into a structure. For Mitigation professionals and Commissioning teams— It is very important to identify limits on the scope of work as described in SGM-SF Sections 4.2.2 d and and 4.2.2 f. Advisory Example 2— Approved processes for handling and disposing of contaminated soil are beyond the scope of SGM-SF. Advisory Example 3— Approved processes and designs associated with federal, state or local requirements when exhausting potent vapor concentrations are beyond the scope of SGM-SF. Advisory Example 4— Complete details for system design for mitigating the hazards of flammable gas are beyond the scope of SGM-SF. Responses shall be sought Advisory— Responsibility is inherently owned by the mitigation professional for safe practices during work. 13.2.2 Existing Measurements Advisory— Not all indoor air VI measurements are conducted under closed-building conditions. Existing measurements need to be evaluated to optimize system design and worker health protection. 13.3 Building Investigations and Systems Design Advisory— Pressure field extension (PFE) analysis is required and includes that test ports be provided for future verification of PFE. Advisory—Durability of pipe joint configurations is important to prevent condensed chemical compounds from escaping the pipe within a home. 13.4.2 Non-habitable air spaces Advisory— Ventilation can be found justifiable but an evaluation of impacts to other portions of the building is important. See Annex A.