Resistance of building foundation to radon penetration

Two-dimensional model of the steady-state diffusion radon transport from the soil to the ground floor of the building is developed. Radon concentration distributions in the soil and the living space are calculated at different foundation geometries. The model considers radon entry from enclosing structures, outside air, and diffusion from the soil. The radon field under the building is described. The quantitative criteria for the resistance of the building foundation to radon penetration from the soil are defined. It is found that the resistance of the ground slab to radon penetration and radon concentration in the plane of the soil structure contact have a decisive influence on indoor radon, and that the initial distribution of radon concentration in the soil changes significantly after the building erection. These changes depend on the radon potential in the soil, its radon permeability, resistance of the floor structure to radon penetration, and building geometry.