Initially, the discussion had focused on whether to abolish this obligation, which stems from a 1968 building regulation that has provided the country with the highest ratio of shelter space to national population, said a report on the daily Corriere del Ticino.
According to the original proposal, the shelters would be built only in hospitals. However, the March tsunami-triggered nuclear crisis in Japan has pushed the majority of lawmakers to vote in favour of maintaining the obligation for residential properties to have secure fallout rooms.
Only those buildings with over 38 apartments must be equipped with shelters, and they must be big enough to hold at least 25 people at a time, the paper said.
Switzerland already has an extensive network of fallout shelters in place, not only in government buildings, such as schools, but also in all residential buildings built after 1968. The nuclear shelters must be able to withstand a blast from a 50 megatonne explosion at a distance of 700 metres.