APPLICABILITY OF VENTILATION SYSTEMS FOR REDUCING THE INDOOR RADON CONCENTRATION.

An analysis is presented of the ability of balanced mechanical ventilation systems to reduce the radon concentration in residential buildings efficiently. The analysis takes into account the following parameters: radon supply rate into the building, ventilation intensity, required indoor radon concentration and energy consumption. It is shown that the applicability of ventilation systems is limited mainly by energy consumption. Ventilation systems can be considered energetically acceptable if the ventilation intensity does not exceed 0.6 h-1, i.e. radon supply rate should not exceed 60 Bq/m3h for a required indoor radon concentration of 100 Bq/m3. Energy consumption can be significantly reduced by operating the ventilation system in a cyclic mode. Simulating the behavior of ventilation systems in time has been found as a useful tool for their design. In order to express by one parameter energy consumption and radon reduction, a completely new quantity-the 'radon-related energy need' has been proposed.

Radon diffusion coefficients and radon resistances of waterproofing materials available on the building market.

This paper presents radon diffusion coefficient values and radon resistance values determined for 650 widely-used waterproofing materials divided into 29 groups according to their chemical composition. The reliability of two different approaches for determining the radon resistance is discussed, and differences between the two approaches are identified. A comparison between the radon resistances of waterproofing materials and the requirements prescribed by various building standards indicates that some requirements are unnecessarily strict. It is shown that the most effective approach for setting the requirements is to prescribe several minimum radon resistance values in dependence on the parameters of the building and the subsoil.