Phone: (714) 730-5397

Phone: (714) 730-5397

Design and Implementation of a Subslab Depressurization System (SSDS) in San Diego, California

Home/California Environmental Consulting, Environmental Contracting, Remedial Solutions, Sub Slab Depressurization, Uncategorized/Design and Implementation of a Subslab Depressurization System (SSDS) in San Diego, California


  • 65,000 square foot slab on grade, concrete tilt up building
  • Historical use: manufacturing filter membranes
  • Chemicals of Concern (COC’s): TCE and chloroform
  • TRG coordinated its Subslab Depressurization System work with two Fortune 500 consulting firms who did not have SSDS construction capabilities


  • Due to the manufacturing operation that was in the building prior to SSDS construction, several trenches and swales needed to be filled in
  • Previous environmental investigations resulted in hundreds of “holes” from 1” to 18” in diameter that 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


  • 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

  • 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 tenant’s 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


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