Sub-Slab Depressurization Systems for Elevated Levels of TCETrichloroethylene (TCE) is a chemical most commonly used in dry cleaners, the automotive industry. and metalworking industries. It also can be found in some household products such as aerosols, paint strippers, varnishes and paints. In businesses that use trichloroethylene or buildings near companies that utilize TCE, elevated concentrations may be present in the groundwater and soil beneath the structures. TCE can easily turn into vapor form which can rise from the groundwater or soil and enter into a building through gaps and cracks in the foundation. The entry of toxic soil vapors into a structure is most commonly referred to as vapor intrusion.
If elevated levels of TCE are found within a structure and determined to be harmful for the occupants inside, steps need to be taken to mitigate that risk. This also applies for new construction properties near contaminated areas. By far the most proven method of mitigating TCE vapors from a structure is sub-slab depressurization. A properly designed sub-slab depressurization system will deter rising soil vapors from entering a structure and will reduce TCE levels to a negligible or non-existent level inside. Structures built over former dry cleaning sites, metal manufacturers, and automotive manufacturers are all at risk of harmful trichloroethylene vapor intrusion, and many times the occupants of said buildings are unaware of their exposure. As soon as proper soil and groundwater testing is performed showing dangerous TCE concentrations, the mitigation process should begin. In over 22 years of business, Lifetime Environmental Solutions has designed and implemented thousands of sub-slab depressurization systems in commercial buildings and residential homes alike. Give us a call today for a free, no obligation sub-slab depressurization quote. |
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Trichloroethylene (TCE) Health Risks
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There are immediate and long term health effects from exposure to elevated concentrations of TCE in the air. How each individual is affected and to what magnitude is dependent on multiple factors such as the individuals health, personal habits (smoking, drinking), and previous exposures to harmful air toxins. Health effects from TCE are also dependent on the length of exposure, and the concentrations of TCE present during exposure.
Immediate health effects of TCE exposure include nausea and vomiting, liver injury, heart problems, eye, nose and throat irritation and neurological issues. These symptoms typically arise when TCE levels are measured above 50,000 ppbV which is considered ultra high. Exposure to this degree is mostly found in occupational settings. Long term effects of TCE exposure can include the development of certain cancers such as kidney, liver, and non-Hodgkin's lymphoma, as well as birth defects in babies born from pregnant mothers exposed to the chemical over time. It isn’t difficult to build up long term exposure to TCE if your workplace is affected, as many of us spend up to 10 hours a day in such settings. As with radon gas, vapor intrusion is something that needs to be addressed as soon as it is found inside of a livable structure to prevent loss of life. |
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Sub-slab Depressurization Systems
Sub-slab depressurization systems as mentioned before are designed to deter rising soil gases and vapors from entering a structure. This is done by creating a negative pressure underneath the slab. To create the negative pressure needed for proper mitigation under a structure, collection points need to be dug and typically an active fan is necessary to draw air from those points through a PVC or stainless steel pipe sealed to the top of those points. To determine where the collection points are created, extensive pressure field extension (PFE) testing should be performed before and after install to ensure that the entire structure is covered. In commercial buildings, multiple collection points and fans will be necessary to cover the larger footprint. In residential homes built near contaminated sites, typically only one collection point and fan will be necessary. After the proper amount of collection points are created and the right sized fans are in place, post-testing is necessary to prove that the TCE contamination is no longer a threat to the health of the occupants in the building. If the building is without a slab on the lowest level (i.e gravel or dirt crawlspace) a vapor barrier will be necessary to trap and remove the vapors rising up from the soil and groundwater. The addition of piping and a fan to a vapor barrier is known as sub-membrane depressurization. If your home or commercial building is in need of a sub-slab depressurization system or a sub-membrane depressurization system to reduce the risk of TCE vapor intrusion, Lifetime Environmental Solutions is here to help! Give us a call now for a free estimate.