Development of DIN standards regarding structural measures for radon protection. Final report

The report comprises four work packages. In work package 1, an overview of the situation of the currently valid regulations on radon protection in European countries is given at the beginning. This includes general building regulations with references to structural radon protection, radon standards as well as other publications from the public sector. This compilation is supplemented by an overview of the situation in North America. Only in three countries (Austria, Czech Republic and Canada) radon-specific building standards have been introduced. In all other countries considered, regulations for determining the radon soil potential (usually via so-called radon maps) have been introduced for specific localities. Several countries (Belgium, Denmark, England, Finland, Ireland, Norway, Switzerland, Czech Republic) have also published more or less detailed official publications on radon protection in buildings, which partly compensate for the lack of building standards. In the second part of WP 1, the radon standards from Austria, the Czech Republic and Canada are described and evaluated in detail. Finally, conclusions and recommendations for the development of the German radon standard are formulated and aspects that are not or not yet satisfactorily clarified are pointed out. In work package 2, selected non-normative publications from European countries are presented and evaluated. The extensive technical literature on radon protection was reviewed and evaluated with regard to relevance for the DIN standards work. Specialist publications on partial issues (e.g. on health issues, individual geological aspects, regional specifics, etc.) and on example presentation were not included in the evaluation. Publications that contain results that are particularly relevant for the standardisation work were used for the evaluation. The following list provides an overview of the evaluated publications: - Radon Manual Germany (2019) - Radon Manual Switzerland (2000) - Publication BR 211 "Radon - Guidance on protective measurements for new buildings" (England, 2015) - Brochure series of the Technical University of Prague (Czech Republic) on radon protection (2017) On the topic of the durability of radon protection measures, which was investigated in work package 3, only a few European publications could be consulted. Only two comprehensive studies from England (2011) and Sweden (2002) as well as a study on special case situations from Austria (1994) were available. In the studies evaluated here, various structural and ventilation remediation solutions were considered. Radon measurements before and directly after the remediation as well as at intervals of several years afterwards can be used to assess the effectiveness of the different solutions as well as their durability. With regard to the efficiency of different measures, the study from England showed significant differences between different approaches. In particular, active subsoil extraction delivered good results. It is important to note that it was not always possible - regardless of the measure chosen - to fall below the desired target value. In particular, the Swedish study covered a large scope of solutions with 91 examples spread over 12 different remediation options. Due to the duration of the Swedish study of 10 years, it was also possible to capture changes in the effectiveness of the solutions over time. Work package 4 deals with the topic of "radon impermeability". Essentially, this is understood as the property of materials or building products to prevent diffusive entry of radon-containing soil air from the subsoil. An assessment is usually carried out by a standard-based laboratory measurement of the radon diffusion coefficient or characteristic values derived directly from it. In Germany, for example, the radon diffusion length is used as a criterion. Throughout Europe, however, there are different procedures for evaluation, which often cannot be directly compared with each other. Meaningful measurement series of the radon diffusion coefficient exist in particular from the Czech Republic. It has been shown that the test value can vary by many orders of magnitude between different product groups and can even vary considerably within a group. In addition to (areal) diffusive radon entry into the building, (local) convective entry plays an important role in practice. An attempt was made to make an order-of-magnitude estimate of this proportion with the help of Hagen-Poiseuille's law.