Vapor intrusion is the movement of chemical vapors from contaminated soil and groundwater into nearby buildings through openings or cracks in the building foundation or through the naturally occurring pores in concrete. Once inside, vapors can accumulate and pose short- and long-term health risks. To mitigate these risks in a new commercial building, the Bank of North Carolina selected WithersRavenel to design a subslab soil exhaust system.
With this system, vapor removal happens in three stages. First, a layer of washed clean stone beneath the building’s concrete slab allows vapor to collect underground rather than immediately penetrating the building. Next, a strong fan draws the vapor out of the stone layer and into a series of exhaust pipes. Finally, the vapors are expelled through an opening in the roof, where they are dispersed in the outdoor air. The result is in interior space that is safer for working and doing business.