Session Title: Radiation Protection of the Public and the Environment FAILURE OF PREVENTIVE MEASURES AGAINST RADON PENETRATION FROM THE GROUND IN A NEW-BUILT FAMILY HOUSE - A CASE STUDY

A system of preventive protection of houses against radon penetration from the ground [1] has been in operation for more than 15 years in the Czech Republic. The determination of a so-called radon index of the building site represents the first step. The assessment is based on measurements of soil gas radon concentration and on the determination of soil permeability. During the years, the method was modified several times, especially the recommendation dealing with the classification of soil permeability, but the base remains stable: The soil characteristics are measured in-situ and protective measures are designed with respect to the measured properties of the soil and to the dwelling design. The site-specific, individual approach should enable to propose an optimal preventive strategy corresponding to local conditions. If the radon index is other than low (i.e. medium, or high), the building must be protected against radon in accordance with the Czech Atomic Law. Protective measures should be designed and installed according to the Czech National Standard [2]. Basic principles of the protection can be summarized in the following way: