Vapor Intrusion: 5 Things You Should Know

What is Vapor Intrusion?
Vapor intrusion (VI) is the migration of chemical vapors into indoor air, entering buildings through cracks in the foundation, through the building slab, around pipes, penetrations, or drain systems. VI occurs after chemicals have been spilled or dumped, vaporize, and then migrate into the building.

1. It can impact public health
VI can pose serious potential health and safety risks for building occupants. Many of the chemicals of concern are carcinogens and can have significant impacts to sensitive populations such as children, pregnant women, and the elderly. 

2. It can impact property value
VI may result in a reduction of property value. VI issues are often discovered during property acquisitions or during redevelopment. If VI is discovered as a potential environmental risk, property value can decrease due to the need for a mitigation system or the perceived risk associated with VI and effects to building occupants. 
3. Size doesn’t matter
Sources of environmental contamination, and subsequently VI, can vary. It isn’t always the large manufacturing facility that seems most obvious, but could be a small dry cleaner or gas station.

4. Vapors travel the path of least resistance
Unlike groundwater, which typically flows downhill, vapors can often travel a different path. Vapors travel the path of least resistance through the subsurface, frequently through sub-grade utility corridors or gravel sub-base. The vapors can then accumulate under buildings and enter the building due to preferential pathways and pressure differentials.

5. The right strategy for mitigation is key
The strategy for a VI mitigation system is key to protecting the health of your building and its occupants. Designing a vapor mitigation system for a new building will be different than mitigating an existing building. The type of building foundation, sub-grade base material, and the overall severity of contamination can impact the mitigation strategy. Our environmental team has proven success with VI mitigation systems and achieving regulatory approval of our design strategies. 

BLE is leading the vapor intrusion industry and has implemented various vapor mitigation solutions across the Southeast.

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