Lead Agency: Norwegian Radiation and Nuclear Safety Authority (DSA). Website: The mandatory regulations exist for schools and kindergartens and includes legally binding radon limit values for indoor radon. The limits are 100 Bq/m3 (action level) and 200 Bq/m3 (maximum level).  For buildings whit high public occupancy in general, there are only recommended guidelines.  https://www2.dsa.no/dav/906ecb0b6c.pdf (in English, see Section 6 paragraph 6)