Radon fans play a crucial role in many radon mitigation systems. Radon is a naturally occurring radioactive gas that is the second most common cause of lung cancer. Since the air pressure in most houses is lower than the pressure within soil around it, houses can have a sort of vacuum effect that pulls this dangerous gas into them through the foundation. Luckily, some radon mitigation systems can decrease the amount of radon entering a home by as much as 99 percent. The preferred method of radon prevention is called sub-slab depressurization (SSD) because it keeps radon from entering the home at all; however, there are fans that will fight radon without having to penetrate the slab of a house. The following is a list of the different types of fans that are used in radon prevention systems and will help choose the right radon mitigation system for one's house.
Room Pressurization Fans
These fans are mounted above ground and draw air from outdoors or upper levels of a house and force it into the basement areas. The idea is that these fans can change the air pressure in the basement so that instead of drawing radon up, it pushes it down. These fans are the easiest to install because they work entirely above ground, but they are the least effective. Climate, house construction, and the amount of time that doors and windows are open in the house will all affect how well this type of fan works. These fans should only be used in smaller residential houses and only after better more efficient SSD fans have been considered.
Low and Medium Power SSD Fans
Low and medium power fans are ideal for homes that have gravel installed below the slab because the gravel is quite porous. For this reason, more often than not, these fans are generally installed during new construction after the gravel layer and foundation have been laid. These fans are quieter and last longer than most other types of fans. Their low power also draws less electricity which will be reflected in home owners’ electric bills. These fans can be connected to either 3 or 4 inch piping for its flow and exhaust. These fans usually only need a single slab penetration.
High Flow SSD Fans
These fans are commonly used on houses that are being retrofitted for radon reduction. They protect against air leakage and work particularly well beneath foundations that do not have enough gravel below them to make the sub-slab layer very porous. The biggest of these fans with the highest flow rates are used for giant structures like schools and office buildings. High flow fans for homes usually use either 4 or 6 inch piping and may require more than one slab penetration to properly do the job; however, big industrial fans of this style will require 6 to 10 inch piping as well as many slab penetrations and exhaust ports.
Suction SSD Fans
Suction fans work best in areas where the sub-slab material is not very porous. This situation usually occurs where sand or dense clay exist beneath the slab. For the most part these fans require 3 inch piping and multiple slab penetrations to draw enough air to be efficient. The larger versions of these fans are recommended for areas at higher altitudes where air is thinner.