Extraction systems as construction techniques to prevent the entry of radon gas in homes

The health risk associated to high radon levels in living spaces leads to perform remedial actions in buildings with radon reduction techniques to reduce radon concentration down to acceptable levels. Within this type of solution, extraction systems, consisting in sumps buried in the ground and connected to the outside through pipes, have demonstrated a high effectiveness in reducing the flow of radon that penetrates into a building from the field. This article presents the results of effectiveness of 4 extraction solutions implemented in a module representative of a home, built in an area with high radon concentrations. Effectiveness is studied depending on the locations of the sumps, with centered or perimeter situation under the floor of the module, and with different types of expulsion of gas, natural convection or forced convection. The main conclusion include the high efficiency displayed by extraction system, with reduction ranges between 91% and 99%, with the exception of the system that use the sump buried by the outer perimeter of the module, and working by natural convection, which actually awarded only in the range of 53% to 58%.