Vapor intrusion

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Since vapor intrusion is caused by contaminated soil, the Environmental Protection Agency (EPA) has done extensive research into how property owners can protect their buildings.  One of the recommendations is to install a radon mitigation system, which can also remove soil vapors from below the foundation before they enter a building.

That is why OES provides several vapor intrusion mitigation options that address all kinds of contamination and foundation types:

• Sub-Slab Depressurization (SSD): SSD is considered the most practical vapor intrusion mitigation strategy for existing and new structures.  The system draws air from beneath the slab using a fan-powered vent to create lower sub-slab pressure relative to indoor air pressure.  So even if there are cracks, gaps, and holes between the building and the subsurface, vapors flow downward.  Which is why a well-designed depressurization system will prevent toxic vapors from intruding into living spaces.
• Sump Pit Depressurization System (SPD): If your property has a high-water table in the ground, then an SPD is a good option.  An SPD is when a sump pump pit acts as a suction pit.  A PVC pipe runs to a fan, which applies a vacuum to the sump pump pit, collecting and discharging vapor outside.
• Sub-membrane Depressurization Systems: A sub-membrane depressurization system is similar to a sub-slab unit, but they are for buildings with crawl spaces where there is no slab or a partial slab.  A vapor barrier or membrane is placed on the floor or directly on the soil, acting as an impermeable layer against gasses.  One or more suction pits go beneath the membrane where they create negative pressure under the property so that vapors do not rise into the building.
• Pressure Field Extension Testing: A soil communication tests, or PFE test, is a diagnostic analysis used in radon and soil vapor extraction by using a manometer and several pilot holes in the slab to determine how easily air can move under the foundation.  The test is also conducted again after installation to check the effectiveness of the system.

OES can also install vapor pins for diagnostic and annual maintenance.  The vapor pin is a reusable sub-slab soil gas sampling device constructed of a single piece of metal.  It has a single-piece design, along with a silicon sleeve to eliminate potential leak points.  It provides a sealable measurement point for the annual maintenance of the system.