Sub-Slab Depressurization Systems for Commercial Properties
Commercial properties such as office buildings, schools, hospitals, factories, warehouses, airports, and stores all can have indoor air issues caused by harmful soil gases rising up and entering through the slab. The most common indoor air issue across the country is the entry and build up of radon gas. Radon gas is an invisible naturally occurring soil gas that derives from the breakdown of uranium in the soil. When inhaled into the lungs over a long period of time, the radioactivity can cause mutations that end in lung cancer. According to the EPA radon gas kills over 21,000 Americans every year. Long term exposure to radon gas is not a hard thing to accomplish when high concentrations exist inside your place of work as most of us spend 8-10 hours a day there. Detecting radon gas early with a proper radon test can save the lives of current and future occupants. Another indoor air contamination concern for commercial structures is vapor intrusion. Vapor intrusion occurs when vapor forming chemicals in the subsurface rise up and enter into a structure. These vapor forming chemicals include volatile organic compounds (VOCs) like benzene and trichloroethylene, semi volatile organic compounds (SVOCs) like naphthalene, and explosive hazards such as gasoline, diesel, and jet fuel. Typically these issues arise when a building is near a former dry cleaning facility, metal manufacturing company, or a gas station. Exposure to high concentrations of chemicals such as trichloroethylene (TCE) from vapor intrusion can lead to a variety of health effects including cancer and birth defects. As with radon testing in a commercial building, vapor intrusion testing should always be performed by a certified professional. If your building has tested high for either radon or a harmful chemical vapor there is a solution! With the installation of a sub-slab depressurization system the soil gasses rising up into the structure will be diverted to a safer area therefore reducing the concentrations inside of the structure to a safe level. Lifetime Environmental Solutions has installed thousands of sub-slab depressurization systems over our 22 years of business and we hold certifications through AARST and the NRPP. Give us a call today for a free, no obligation sub-slab depressurization system estimate!
Sub-slab Depressurization Methods
Every commercial building has its own unique features and because of this, all sub-slab depressurization (SSD) systems are custom built to fit the needs of the structure. A typical sub-slab depressurization system consists of PVC or stainless steel piping (dependent on the chemicals present), an in-line fan, and a manometer to measure the fan's effectiveness. In larger commercial buildings, multiple pipes and fans will be required to cover the large footprint. Prior to installation a pressure field extension (PFE) test will be performed to determine where the collection points are to be dug. During installation, a 4” to 5” hole is cored into the slab and material is removed from underneath. The piping for the SSD system is sealed air tight to the collection points and runs up and out of the structure. Per code, the piping must vent above the roofline to prevent re-entry. There exist multiple types of mitigation fans that can be used for a variety of different soil types and larger footprints. During initial inspection of the building and subsequent PFE tests we can determine which type of fan will be most effective.
Some commercial buildings either do not have a slab on the lowest level or only a partial slab present. In this case, a vapor barrier will need to be installed and sealed air tight to the open soil. The vapor barrier will trap rising soil gasses even more effectively than a concrete slab. After the vapor barrier is installed, collection points are dug under the barrier and the mitigation system piping is sealed down to the barrier above those points. The rest of a sub-membrane depressurization is essentially the same as a common SSD system. In new construction properties, the utilization of a vapor barrier and a concrete slab can greatly reduce both radon and vapor intrusion indoors. Lifetime Environmental Solutions will assist in the implementation of sub-membrane depressurization systems in both new construction projects and existing structures, Give us a call today for a free quote!
One of the most effective forms of SSD is drain-tile depressurization. Drain-tile depressurization utilizes the corrugated drain-tile beneath the slab to draw airflow through that predesigned pathway. By using that pathway, the sub-slab depressurization is able to cover the entire footprint of the structure with less collection points and fewer fan units. If the property is without drain-tile, Lifetime Environmental Solutions can install drain-tile under the slab through various trenching techniques. New construction properties should strongly consider having drain-tile added before pouring the slab not only for drainage but also for vapor mitigation usage. Give us a call today for a free consultation.
Block Wall Depressurization
In some cases, the soil gases entering a building are not only entering from the slab. Open block walls can cause a stack effect that will draw gasses from the soil up through the blocks and into the structure with relative ease. To combat block wall entry, the tops of the block walls will need to be sealed air tight, and a pipe will need to be added into the wall to draw those gasses out. Block wall depressurization is simply an addition to a typical SSD system to ensure that the entire building is properly covered. Lifetime Environmental Solutions provides block wall depressurization services in addition to traditional SSD services for buildings that need it. Give us a call now for a free quote!