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.
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.
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.
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.
- MeSH
- konstrukční materiály analýza MeSH
- radon analýza normy MeSH
- referenční standardy MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
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. Three sets of samples of polyethylene damp-proof membranes were sent to these laboratories for measurement. Till today, the organisers received only five sets of results. The results showed a great variability among laboratories involved.
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. In addition, the study reveals that the efficiency of remediation does not depend on the installation costs. Cost-benefit analysis and cost-effectiveness analysis lead to the conclusion that remedial measures reducing the indoor radon concentration from values above 1000 Bq/m(3) are always acceptable and reasonable. On the other hand, these techniques can neither help the designer to choose the proper remedial measure nor provide information resulting in improved remediation.
Reasons of low effectiveness of radon remedial measures have been studied on several unsuccessfully remediated houses. Based on the thorough analysis, factors responsible for failures are clarified. The possibilities of how to improve the effectiveness of installed measures are also discussed. Experience in this field is documented by several examples of additionally mitigated houses. After application of additional measures, indoor radon concentration in the studied houses decreased in average 5.3 times. Costs for additional mitigation were at least four times cheaper compared with costs required for installation of original measures.
- MeSH
- bydlení MeSH
- dávka záření MeSH
- dekontaminace metody MeSH
- financování organizované MeSH
- monitorování radiace metody MeSH
- radiační ochrana metody MeSH
- radioaktivní látky znečišťující vzduch analýza MeSH
- radon analýza MeSH
- znečištění vzduchu ve vnitřním prostředí analýza prevence a kontrola MeSH
- Geografické názvy
- Česká republika MeSH
This paper describes a new device and a method to determine the radon diffusion coefficient in damp-proof membranes developed in the Czech Republic. The main advantage of the device is that it enables tests to be carried out in all the known measuring modes used throughout Europe. Two recently developed computer programs are presented for the numerical modelling of the time-dependent radon transport through damp-proof membranes. According to this method, the radon diffusion coefficient is derived from the process of fitting the numerical solution to the measured curve of radon concentration in a receiver container. Numerical simulation and measured data are also compared. Reasons for disagreements between different methods and specific configurations of the measuring device are also discussed.
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 Jachymov. Results of the efficiency analysis are presented. Experience obtained up to now indicates that it is almost impossible to reduce the gamma dose rates in such buildings to the level corresponding with the natural background, because some of the gamma radiation sources cannot be completely removed from the building structures.
- MeSH
- bydlení MeSH
- dávka záření MeSH
- dekontaminace metody MeSH
- financování organizované MeSH
- hornictví MeSH
- monitorování radiace metody MeSH
- radiační ochrana metody MeSH
- radioaktivní látky znečišťující vzduch analýza MeSH
- radon analýza MeSH
- stříbro MeSH
- uran MeSH
- znečištění vzduchu ve vnitřním prostředí analýza prevence a kontrola MeSH
- Geografické názvy
- Česká republika MeSH
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.
- MeSH
- bydlení MeSH
- dávka záření MeSH
- dekontaminace metody MeSH
- financování organizované MeSH
- monitorování radiace metody MeSH
- radiační ochrana metody MeSH
- radioaktivní látky znečišťující vzduch analýza MeSH
- radon analýza MeSH
- znečištění vzduchu ve vnitřním prostředí analýza prevence a kontrola MeSH
- Publikační typ
- hodnotící studie MeSH
- Geografické názvy
- Česká republika MeSH
