This project in Los Angeles, California, involved a building that formerly housed a metal plating shop. The processes involved with the plating operations used PCE (a chlorinated solvent that readily volatilizes) and released it into the soil beneath the site. Soil vapor surveys and assessments have identified the threat to the health of the occupants of the building due to the intrusion of PCE vapors into the building. Following a site inspection, The Reynolds Group performed a pilot study to determine the applicability of sub-slab vapor intrusion mitigation to protect the occupants from exposure to PCE.
Due to the release and subsequent human health threat occurred after the building was constructed, the options for mitigating vapor intrusion were limited. The buildings slab-on-grade construction further limited the options. Through the pilot study, TRG demonstrated that applying a vacuum (depressurization) to the interface between the bottom of the concrete slab and the soil immediately beneath it, PCE vapors could be captured and prevented from entering the building. TRG then designed a simple and practical depressurization system to be installed to protect the workers at the facility from the human health risk.