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.

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.

Radon diffusion coefficient measurement in waterproofings--a review of methods and an analysis of differences in results.

This paper summarizes information about 16 measuring methods for determining the radon diffusion coefficient of waterproofing materials. We have found that the differences in results for identical membranes, which can be as high as two orders of magnitude, can mainly be attributed to insufficient duration of the tests, insufficient radon concentration to which the samples are exposed, and the use of steady state calculation procedures for data measured under non-steady state conditions.

Basic principles for the development of a common standardised method for determining the radon diffusion coefficient in waterproofing materials.

Paper presents the principles for unified test methods for determining the radon diffusion coefficient in waterproof materials in order to increase the accuracy, repeatability and reproducibility of the results. We consider this very important, because an assessment of the radon diffusion coefficient is required by several national technical standards when waterproofing acts as a radon-proof membrane. The requirements for key parameters for one test method performed under non-stationary conditions and for two methods performed under stationary conditions are described in this paper.

1st International comparison measurement on assessing the diffusion coefficient of radon.

Radon diffusion coefficient is a material parameter which is usually used in the radon mitigation measures design. There are different approaches used for radon diffusion coefficient measurement and assessment. The International comparison measurement which was jointly organised by National Radiation Protection Institute and Faculty of Civil Engineering CTU Prague in 2009 and 2010 has registered 11 laboratories from all over the world.

Limited applicability of cost-effectiveness and cost-benefit analyses for the optimization of radon remedial measures.

Ways of using different decision-aiding techniques for optimizing and evaluating radon remedial measures have been studied on a large set of data obtained from the remediation of 32 houses that had an original indoor radon level above 1000 Bq/m(3). Detailed information about radon concentrations before and after remediation, type of remedial measures and installation and operation costs were used as the input parameters for a comparison of costs and for determining the efficiencies, for a cost-benefit analysis and a cost-effectiveness analysis, in order to find out whether these criteria and techniques provide sufficient and relevant information for improving and optimizing remediation. Our study confirmed that the installation costs of remediation do not depend on the original indoor radon level, but on the technical state of the building.

Investigation and remediation of houses affected by radon phenomena connected with earlier exploration of silver and uranium ore.

The sources of gamma radiation inside buildings affected by earlier silver and uranium mining activities are discussed. Possibilities how to reduce gamma dose rates from building materials were studied on several houses located in the old mining town Jáchymov. Results of the efficiency analysis are presented.

Radon diagnosis procedures focused on dwellings with ineffective measures against radon.

An efficiency analysis of remedial measures launching in the Czech Republic before 2004 revealed that in 52% of houses the remediation was not successful. An example of the house with an ineffective mitigation is described in order to present radon diagnosis procedures focused on the identification of critical factors responsible for the remedial mitigations insufficiency. A description of additional measures application is presented and results of the final efficiency evaluation are discussed.