Every construction project has its own idiosyncrasies and problems that come up. Sometimes these problems don’t come up until after the project has long been completed. As the earth settles over time the geotechnical surveys that were completed can become obsolete and won’t always take into account the gases and vapors that are trapped under water-tables and compressed sediment or soil. This eventuality has begun to be more commonplace as structures that were built decades ago are experiencing settling and where new construction was hastily erected.
To combat the rising number of instances and structures where vapor and gas intrusion are happening, new technologies are being developed and implemented to keep the spaces safe. The construction and MEP engineering communities are always working to come up with new and creative ways to mitigate the problems facing building owners and occupants today.
As regulations increase across the country regarding evaluating vapor intrusion pathways, so too is the need for proper mitigation systems. The first step towards properly mitigating vapor intrusion in a commercial building structure involves sub-slab soil gas sampling to identify the levels assess the potential risk.
If vapor intrusion is identified, and found to be above the accepted screening levels, a mitigation system should then be designed and put in place. For existing commercial buildings where vapor intrusion is identified, currently the most common mitigation system is the sub-slab depressurization system. These systems are used to mitigate indoor vapors arising from subsurface contamination.
