Vapor Intrusion Mitigation Systems in Gas StationsPetroleum Vapor Intrusion (PVI) is a real concern for gas stations and buildings present over former gas station sites. Vapor intrusion occurs when contaminants in the subsurface beneath a structure reach vapor form and rise up to enter. PVI is a type of vapor intrusion that occurs when volatile petroleum hydrocarbons such as gasoline, diesel fuel, or jet fuel turn to vapor form and enter a building. Once these vapors are present inside of a structure they can ignite and explode. At lower quantities, these vapors may not explode, but cause detrimental health effects to the occupants of the structure. In either case, it is important to be mindful of possible PVI when taking ownership of a gas station, or a building over a former gas station site.
For the most part, PVI is caused by a leaking underground storage tank that hasn’t been addressed. In many cases these tanks may be forgotten about or the owners may have had no knowledge that the tanks were leaking. Proper testing for PVI should be performed on gas stations and buildings over former gas station sites to ensure the safety of the current and future occupants. If testing shows that a vapor intrusion issue is present, and results from the vapor intrusion screening level (VISL) calculator show a high risk for the buildings occupants, vapor intrusion mitigation should be performed. Lifetime Environmental Solutions specializes in vapor intrusion mitigation and has over two decades of experience in the field. We will work with you to find the best possible vapor intrusion solution for your building to get you back to breathing healthy clean air once again. Give us a call now for a quote! |
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Active Soil Depressurization Systems (ASD)
Active soil depressurization is the most common and proven method to divert and remove toxic soil vapors from underneath a structure. Active soil depressurization works by drawing air out from under the slab of the building to create a negative pressure that either will redirect the soil gasses away from the building, or draw the gasses into a vent pipe to be diverted to a safer area. The type of ASD system a building will require depends entirely on how the building is constructed.
Sub-slab Depressurization
The most common form of ASD is sub-slab depressurization (SSD). Sub-slab depressurization systems consist of PVC or stainless steel piping, an in-line fan, and a manometer to measure vacuum pressure. A hole (or multiple holes depending on the size of the building) is drilled into the slab and material from under the slab is removed to create a collection point. Once the collection points have been dug out, the piping and fan units are attached and vented out above the roofline of the structure to prevent re-entry. Before and after a sub-slab depressurization system is installed, proper pressure field extension (PFE) testing should be performed to ensure that the system will cover the entire footprint of the building. All SSD system installations should be performed by a certified mitigator as PFE testing and the implementation of a proper SSD system is a complicated process. SSD is a proven and affordable method to mitigate vapor intrusion issues in any structure. Give us a call today for a free sub-slab depressurization system estimate.
Sub-membrane Depressurization
In buildings that only have a partial slab, or no slab at all in the lowest level, a vapor barrier should be placed and sealed air tight to prevent further entry of soil vapors. Properly installed sub-membrane depressurization systems have vapor barriers that trap rising soil gasses, and vent piping with a fan to draw the trapped gasses out. SMD systems are aesthetically identical to SSD systems on the exterior of the property, and sometimes require stronger fan types to ensure maximum depressurization.
Sub-slab Depressurization
The most common form of ASD is sub-slab depressurization (SSD). Sub-slab depressurization systems consist of PVC or stainless steel piping, an in-line fan, and a manometer to measure vacuum pressure. A hole (or multiple holes depending on the size of the building) is drilled into the slab and material from under the slab is removed to create a collection point. Once the collection points have been dug out, the piping and fan units are attached and vented out above the roofline of the structure to prevent re-entry. Before and after a sub-slab depressurization system is installed, proper pressure field extension (PFE) testing should be performed to ensure that the system will cover the entire footprint of the building. All SSD system installations should be performed by a certified mitigator as PFE testing and the implementation of a proper SSD system is a complicated process. SSD is a proven and affordable method to mitigate vapor intrusion issues in any structure. Give us a call today for a free sub-slab depressurization system estimate.
Sub-membrane Depressurization
In buildings that only have a partial slab, or no slab at all in the lowest level, a vapor barrier should be placed and sealed air tight to prevent further entry of soil vapors. Properly installed sub-membrane depressurization systems have vapor barriers that trap rising soil gasses, and vent piping with a fan to draw the trapped gasses out. SMD systems are aesthetically identical to SSD systems on the exterior of the property, and sometimes require stronger fan types to ensure maximum depressurization.
Petroleum Vapor Intrusion Health Risks
Health risks for occupants spending time in a structure with PVI can vary depending on the concentrations of the toxic vapors and the amount of exposure. One glaring risk that is associated with PVI is the risk of explosion. Across the country there have been cases of buildings situated above leaking underground storage tanks from past or current gas stations that have catastrophic results of petroleum vapor intrusion. At high vapor concentrations it doesn’t take much to set off a devastating chain of events inside of your building. Proper soil and water testing is extremely important to keep this from ever happening. Other health risks associated with petroleum vapor intrusion can include liver and kidney damage, birth defects, and even cancer. Give us a call today for a free vapor mitigation system quote!