Radon Mitigation is used to lower the indoor radon concentrations within the home or building. This is completed by tapping a pipe into the underlying soil (under the slab) and applying vacuum on the soil voids to essentially suck the radon-laden soil gas (air) from under the home or building. The air is then channeled via PVC pipe and vented above the home or building.
The goal on all MEI jobsites is to get that pesky radon is LOW AS POSSIBLE. We have successfully reduced the indoor radon concentrations in multiple homes to under the EPA estimated average outdoor concentration of 0.4 pCi/L. The Environmental Protection Agency (EPA) has established an action level for radon gas of 4.0 pCi/L. This means that radon detected at or above 4.0 pCi/L represents an unacceptable risk, thus, mitigation work should be sought to reduce the concentration. Any exposure to radon gas may present a health risk. At MEI, we guarantee to reduce the indoor radon concentration to 2.5 pCi/L or lower. This is verified by performing follow up testing, post-system installation.
Several design factors are incorporated into our planning phase to give you low post-mitigation results. The four critical design factors:
Extraction Pits – The number of extraction (suction) pits. The location, size, depth, and number of suction pits plays an important role in further reducing the radon. The suction pit(s) is / are created by essentially constructing a "sump-like" void underneath the slab, in order to make it easier for the radon-laden air to migrate from the soil voids into the pipe. It is SUPER important to spend enough time and remove an adequate volume of soil from beneath the slab. This is the dirty part of the job and often gets overlooked. Basically, the more time spent removing soil from under the slab, the better the radon mitigation system will operate. Normally, MEI will remove at least ten gallons of soil (unless connected to drain tile), sometimes more than 20-gallons of soil if the subsurface conditions are tight.
Fan – The fan design is also a crucial component because the fans are designed for different scenarios. For example, we may find clayey soil underneath the slab, where a soil communication test shows inadequate air flow for your typical in-store purchased radon fan. Therefore, a fan designed for high suction / low flow, or high suction / high flow would be able to most effectively reduce the radon.
Soil Type – The soil type plays a large role on the design / installation of a radon system. Stiffer soils such as clay prohibit air flow in comparison to sandy soils or gravelly soil, where soil voids are large and air flow is adequate.
Pipe – Both the pipe diameter and length of pipe affect the air flow. The more pipe and pipe features, such as elbows – the more energy loss due to friction, which will affect system performance. Homes with large footprints may require larger diameter pipe (4-inch over 3-inch) to accommodate the excess air that needs to be cleared from the larger subsurface footprint. This can also be done by constructing more suction pits.