Manufacturing Complex with Vapor Intrusion of a Flammable Soil Gas


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Manufacturing Complex with Vapor Intrusion of a Flammable Soil Gas

Vapor intrusion (VI) is the process in which organic chemicals in soil or groundwater evaporate and enter buildings at potentially toxic levels.  A particular concern occurs when flammable vapors are present in concentrations above the lower explosive limit (LEL), where they could burn or explode.  Many volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) are combustible, and their chemical breakdown often generates methane, which is, of course, combustible.  Accordingly, even chemicals that are not highly toxic can pose VI risk from explosion.

Cox-Colvin was asked to evaluate VI at a large operating Midwestern manufacturing facility with the underlying groundwater containing petroleum-related VOCs.  Cox-Colvin employees installed 78 of our patented Vapor PinsTM into the floor using hand-held equipment over a broad area of interest.  Following installation, we screened the sample points for VOCs and flammable vapors, removed the Vapor PinsTM, and plugged the holes, all within two days.  Field screening, verified with lab results, indicated the presence of flammable vapors beneath the floor above the LEL.  The delineation of vapor contamination indicated the need for a vapor mitigation system beneath a small part of the building.