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Home institution University of Maribor Faculty of Civil Engineering Slovenia

Education and Culture Lifelong Learning Programme ERASMUS. Assist.Prof.Dr. Lucija Hanžič. LECTURE 4 Protection of human dwellings against radon www.fg.uni-mb.si/lucija/presentations/2008sakarya-lecture4.ppt. 14 – 18 April 2008. Host institution Sakarya University

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Home institution University of Maribor Faculty of Civil Engineering Slovenia

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  1. Education and Culture Lifelong Learning Programme ERASMUS Assist.Prof.Dr. Lucija Hanžič LECTURE 4 Protection of human dwellings against radon www.fg.uni-mb.si/lucija/presentations/2008sakarya-lecture4.ppt 14 – 18 April 2008 Host institution Sakarya University Technical Education Faculty Turkey Home institution University of Maribor Faculty of Civil Engineering Slovenia

  2. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon Isotopes Protons p = 86 n = 133 219Rn Figure 1. Bohr-Rutherford atomic model. Nucleus www.voyagesolarsystem.org, 28.03.2008. Neutrons RADON atom n = 134 220Rn Electron shells n = 134222Rn Electrons e = 86 Figure 2. Sign for radiation danger. Figure 3. Basic types of radiation. Wikipedija, http://en.wikipedia.org/wiki/Radioactive, 2.3.2007. Wikipedija, http://en.wikipedia.org/wiki/Radioactive, 2.3.2007. 2/6 University of Maribor, Faculty of Civil Engineering Radon and radiation Click for Periodic table Radon is an inert gas, which means that it is chemically unreactive and at atmospheric conditions it is in gaseous form. It is found in form of three isotopes that are all unstable. Half-life is a time period in which half of initial number of radioactive nuclei dacays. Unstable nuclei decay spontaneously into lighter nuclei by emitting particles or energy. The result of this proces is radiation – most well known are α, βand γ. Sheet of paper Since radiation is a natural phenomena our body receives an annual dose of irradiation from natural sources which is amounts to ~ 2.4 mSv. Aluminium plate Lead block Radiation dose measured in Sieverts (Sv) is estemated on the basis of the damage caused on the tissue by a certain type of radiation.

  3. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon 219Rn:4.0 s Half-life of radon isotopes 220Rn:55.6 s 222Rn: 3.8 days Figure 5. Radioactive decay chain of 238U where 222Rn is formed. Applied Techniques Co., http://www.atral.com/U2381.html, 2.3.2007. 3/6 University of Maribor, Faculty of Civil Engineering Table 1. Annual doses from different irradiation sources. Figure 4. Natural sources of radiation and their contribution to annual dose. Irradiation caused by radon and its decay products is one of the important reasons for lung cancer.

  4. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon Figure 6. Sources of radon in dwellings. geoscape.nrcan.gc.ca <09.04.2008> 4/6 University of Maribor, Faculty of Civil Engineering Radon sources in dwellings 1. Cracks in solid floors 2. Construction joints 3. Cracks in walls 4. Gaps in suspended floors 5. Gaps around service pipes 6. Cavities inside walls 7. The water supply Table 2. Concentration of 226Ra in some materials used in construction industry. Indoor concentration 1 Bq = 1 decay per second 1 Ci = 3.7·1010 Bq

  5. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon Figure 7. Types of building fundation. www.indoor-air-health-advisor.com <09.04.2008> 5/6 University of Maribor, Faculty of Civil Engineering Methods for radon reduction New buildings 1. Careful selection of materials 2. Risk assasment – evaluation of soil 3. Adequate building design Old buildings 1. Determination of radon concentration(short-term, long-term) 2. Source determination (soil, building materials, water) 3. Instalation of adeqate radon mitigation system Soil Sealing cracks Soil depressurization House pressurization Natural ventilation Heat recovery ventilation Water Activated carbon filters Aeration Point of entry or Point of use Material Reducing air pressure in cavity walls

  6. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon 6/6 University of Maribor, Faculty of Civil Engineering Further reading Field R.W., radon occurrence and health risk, College of Public Health, Iowa, http://www.cheec.uiowa.edu/misc/radon_occ.pdf, <09.04.2008>. Nazaroff WW, Nero AV (eds): Radon and Its Decay Products in Indoor Air. New York, John Wiley & Sons, 1988. Field RW, Steck DJ, Smith BJ, Brus CP, Fisher EL, Neuberger JS, Platz CE, Robinson RA, Woolson RF, Lynch CF: Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study, American Journal of Epidemiology 151(11):1091-102, 2000. A citizan’s guide to radon. U.S. Environmental Protection Agency, http://www.epa.gov/radon/pubs/citguide.html, <09.04.2008>.

  7. Assis.Prof.Dr. Lucija Hanžič Protection of human dwellings against radon 5/6 University of Maribor, Faculty of Civil Engineering Back

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