Radioactivity in Building Materials ÖNORM S 5200: A Standard in Austria to limit Natural Radioactivity in Building Materials (Revised and definite Version)

The Austrian Standard ÖNORM S 5200, prepared in the early nineties after a prestandard phase (Steger F.) and in use in Austria since 1996, provides the criteria to assess the radiation dose of building materials. Gamma radiation of the radionuclides 40K, 226Ra and thorium are taken into account, as well as the dose due to the noble gas radon, which is released from building materials after the decay of 226Ra. A type of building material is considered acceptable if its yearly effective dose in a room does not exceed 2.5 mSv.y-1. Provisions are made to minimise the required experimental efforts to prove compliance with the standard. There is also al limit of 3.4 µSv.h-1 for external beta radiation due to surfache radiation (from e.g. uranium-glazed tiles), which is derived from the limit of 10 mSv.a-1 as stated in the Austrian radiation protection regulations and 8 hours/day exposure time and corresponds to an activity concentration of about 1 Bq.cm-2 uranium in equilibrium with its progenies.