Background of the Subslab Depressurization System (SSDS)
- 65,000 square feet of Subslab Depressurization System (SSDS) in a concrete tilt up building
- Historical use: manufacturing filter membranes
- Chemicals of Concern (COC’s): TCE and chloroform
- TRG worked coordinated its Subslab Depressurization System work with two Fortune 500 consulting firms who did not have SSDS construction capabilities.
Pre-Work for the Subslab Depressurization System (SSDS)
- Prior to SSDS construction, Due to the manufacturing operation that was in the building, several trenches and swales needed to be filled in.
- Due to borings from previous environmental investigations, hundreds of “holes” from 1” to 18” in diameter needed to be plugged
- The slab was severely impacted with cracks, holes and trenches.
- The slab was sealed which ultimately significantly increased the effectiveness of the SSDS
Construction of the Subslab Depressurization System (SSDS)
- Subslab Depressurization System extraction points were installed along interior walls and roof support beams to minimize impact on future building uses
- SSDS Extraction points were connected to collection pipes hung from the roof beams and trusses
- SSDS extraction blower and carbon filters were installed outside of the building to keep floor space open and available
- 11 SSDS performance observation ports were installed in the floor of the building with flush mounted stainless steel covers
Start Up, Acceptance and Operation of the Subslab Depressurization System (SSDS)
- The California Department of Toxic Substances Control (DTSC) accepted the SSDS design and construction
- Subslab Depressurization System start-up parameters exceeded design specifications.
- More than sufficient vacuum influence was observed at all 11 observation points
- Current owner has requested we reevaluate the SSDS to accommodate tenants request to remove/relocate some extraction pits to accommodate a clean room operation
- Current owner has entered into a contract with TRG to perform routine minimal maintenance and sampling of the Subslab Depressurization System