Sistemas de extracción como técnicas constructivas para evitar la entrada de gas radón en las viviendas

The health risk associated to high radon levels in living spaces leads to perform remedial actions in buildings with radon reduction techniques to reduce radon concentration down to acceptable levels. Within this type of solution, extraction systems, consisting in sumps buried in the ground and connected to the outside through pipes, have demonstrated a high effectiveness in reducing the flow of radon that penetrates into a building from the field. This article presents the results of effectiveness of 4 extraction solutions implemented in a module representative of a home, built in an area with high radon concentrations. Effectiveness is studied depending on the locations of the sumps, with centered or perimeter situation under the floor of the module, and with different types of expulsion of gas, natural convection or forced convection. The main conclusion include the high efficiency displayed by extraction system, with reduction ranges between 91% and 99%, with the exception of the system that use the sump buried by the outer perimeter of the module, and working by natural convection, which actually awarded only in the range of 53% to 58%.El riesgo que supone para la salud el habitar en espacios con altos contenidos de gas radón conlleva a realizar actuaciones en los edificios con soluciones constructivas enfocadas a frenar la entrada del gas para reducir así la concentración interior hasta unos niveles aceptables. Dentro de este tipo de soluciones, los sistemas de extracción constituidos por elementos captadores enterrados en el terreno y conectados al exterior mediante tuberías de expulsión, han demostrado poseer una alta efectividad en la reducción del flujo de radón, que proveniente del terreno, penetra en un edificio. En este artículo se presentan los resultados de efectividad de 4 soluciones de extracción ejecutadas en un módulo representativo de una vivienda, construido en un terreno con altas concentraciones de radón. Las efectividades se analizan en función de las localizaciones de los elementos captadores, con situación centrada o perimetral conforme a la planta del módulo, y con distintos tipos de expulsión del gas, por convección natural o por convección forzada. Como conclusión principal cabe destacar la alta efectividad que manifiestan las medidas de extracción con rangos de reducción que oscilan entre un 91% y un 99%, a excepción de la medida que hace uso del elemento captador enterrado por el perímetro exterior del módulo, y que funciona por convección natural, que únicamente consiguió efectividades en el rango de 53% a 58%

European Atlas of Natural Radiation

Natural ionizing radiation is considered as the largest contributor to the collective effective dose received by the world population. The human population is continuously exposed to ionizing radiation from several natural sources that can be classified into two broad categories: high-energy cosmic rays incident on the Earth’s atmosphere and releasing secondary radiation (cosmic contribution); and radioactive nuclides generated during the formation of the Earth and still present in the Earth’s crust (terrestrial contribution). Terrestrial radioactivity is mostly produced by the uranium and thorium radioactive families together with potassium. In most circumstances, radon, a noble gas produced in the radioactive decay of uranium, is the most important contributor to the total dose. This Atlas aims to present the current state of knowledge of natural radioactivity, by giving general background information, and describing its various sources. This reference material is complemented by a collection of maps of Europe displaying the levels of natural radioactivity caused by different sources. It is a compilation of contributions and reviews received from more than 80 experts in their field: they come from universities, research centres, national and European authorities and international organizations. This Atlas provides reference material and makes harmonized datasets available to the scientific community and national competent authorities. In parallel, this Atlas may serve as a tool for the public to: • familiarize itself with natural radioactivity; • be informed about the levels of natural radioactivity caused by different sources; • have a more balanced view of the annual dose received by the world population, to which natural radioactivity is the largest contributor; • and make direct comparisons between doses from natural sources of ionizing radiation and those from man-made (artificial) ones, hence to better understand the latter.JRC.G.10-Knowledge for Nuclear Security and Safet

Permeability as an important parameter for radon risk classification of foundation soils

Permeability of soils and rocks for gases is one of the main parameters for final radon risk classification of building sites. For the improvement of the method for radon risk classification it is recommended to complete in situ measurements of permeability and/or results derived from grain size analysis by an expert description of parameters of soils and rocks and their changes in vertical profile

Practical usefulness of radon risk maps and detailed in-situ classification of radon risk

The presentation answers the frequent question about the practical usefulness, advantages and disadvantages of radon risk maps and detailed in-situ classification of radon risk. Czech Radon Programme derives the benefit from radon maps on various scales – 1:500 000, 1:200 000 and 1:50 000, as well as from the uniform method for direct detailed classification of radon risk. The reliability assessment of the practical usefulness is based on the direct comparison between the results obtained from detailed in-situ classification of radon risk of building sites and the corresponding reading from the radon risk map. Altogether almost one thousand of detailed radon risk assessments, i.e. tens of thousands of soil-gas radon concentration measurements, were compared with the expected radon risk categories in five radon risk map sheets on the scale 1:50 000. The new results more specify and correspond to the previous results from comparisons performed in 1992, 1995 and 2002. We can prepare quite consistent maps, which can be successfully used to direct the search of existing houses with higher indoor radon values. On the other hand, the risk of underestimation or overestimation in the case of deriving the radon risk classification of a specific building site from the map seems to be too high to use the maps for direct assessment of specific sites. For new buildings, it is recommended to use detailed in-situ measurements and classification

Permeability as an important parameter for radon risk classification of foundation soils

Permeability of soils and rocks for gases is one of the main parameters for final radon risk classification of building sites. For the improvement of the method for radon risk classification it is recommended to complete in situ measurements of permeability and/or results derived from grain size analysis by an expert description of parameters of soils and rocks and their changes in vertical profile.PublishedJCR Journalope

Soil Radon Concentration and Permeability at “Valle della Caffarella” Test Site (Roma, Italy). Evaluation of Gas Sampling Techniques and Radon Measurements Using Different Approaches

Soil gas radon concentration at “Valle della Caffarella” test site (Roma, Italy) was monitored in December 2009 and June 2010, using three different gas sampling and measurement techniques (alpha spectrometry, scintillation cells and ionization chambers). Gas permeability of soil was associated to radon measurements to evaluate its effects on soil radon results. During the winter campaign, the three methods provided comparable results at depths of 50 and 80 cm (stations in areas A and B), where the gas permeability is low. Stations in area C apparently do not respond to this simple model. Determinations carried out at depths of 20 and 30 cm are generally 60 % lower using the continuous radon monitor (alpha spectrometry device), because larger volumes of air are extracted using the built-in pump. The proximity to soil/air interface probably drains atmospheric air into the subsoil and radon-poor air is then delivered to the instrument. This effect is enhanced by larger gas permeability. Results from the summer campaign substantially mirror those of the winter fieldwork, even if soil radon concentrations are strongly reduced both at 30 and 80 cm depth because of enhanced radon release to the atmosphere when soil is drier, warmer and more permeable. The recourse to a mixed approach (Radon v.o.s. probe + RAD7 continuous monitor) shows that the volume of extracted air affects soil radon results less than the combined effect of the probe tip size and the poor sealing of the sampling hole

Preliminary results of radon survey in thermal spas in V4 countries

Radon concentration was measured in 11 thermal spas in Visegrad countries (Czech Republic, Hungary, Poland, and Slovakia). The results showed that in 84% of spas radon activity concentration is less than 400 Bq·m–3. However, areas with radon activity concentration exceeding 1000 Bq·m–3 were found in the Czech Republic and Slovakia as well. Preliminary analyses indicated that the highest radon activities in spas were found in places with thermal pools. Radon concentration in waters used in spas ranged from 0.5 Bq/l to 384 Bq/l. The influence of radon activity concentration in water on radon activity in the air inside the spa was observed. It was found to increase indoor radon with increasing radon in the waters. Correlation with indoor radon and radon in water was more significant for baths and less significant for pool waters. In the cases filling of the bath from water taps, significantly contribute to the increased radon was observed in the pool and bath areas of the spa

Preliminary results of radon survey in thermal spas in V4 countries

Radon concentration was measured in 11 thermal spas in Visegrad countries (Czech Republic, Hungary, Poland, and Slovakia). The results showed that in 84% of spas radon activity concentration is less than 400 Bq·m–3. However, areas with radon activity concentration exceeding 1000 Bq·m–3 were found in the Czech Republic and Slovakia as well. Preliminary analyses indicated that the highest radon activities in spas were found in places with thermal pools. Radon concentration in waters used in spas ranged from 0.5 Bq/l to 384 Bq/l. The influence of radon activity concentration in water on radon activity in the air inside the spa was observed. It was found to increase indoor radon with increasing radon in the waters. Correlation with indoor radon and radon in water was more significant for baths and less significant for pool waters. In the cases filling of the bath from water taps, significantly contribute to the increased radon was observed in the pool and bath areas of the spa