A lot of this sort of information is surprisingly US centric. For instance, you might find building codes that forbid the sort of "non-exposed" room in residential housing as a health and safety issue due to ventilation or emergency exit or other reasons.<p>My rule of thumb is simple.<p>- Know the nearest target.<p>- Know who might hit it with a nuke.<p>- Check the NukeMap ( <a href="https://nukemap.org/" rel="nofollow">https://nukemap.org/</a> ) based on who might nuke it and what nukes they are known to have... to estimate the if you even need to care about shelter. If you're too close to the nearest target theres not much you could hope to do without shelter. If you're far enough then you wont need to care about the immediate attack either.<p>- Missile warning will likely create havoc with transport as people without plans try to suddenly make them. So consider where you spend most of your time during a normal day, and what transport options you have with you then depending on your personal level of paranoia make a decision about the best shelter options based on two things, travel time and level of protection. You should travel for better shelter, but not risk traveling far given the uncertainty of the situation. Just having a basic background understanding of what the suitable shelter would be in your life and this becomes more like knowing where you could hide from sudden rain without an umbrella on a walk down the street.<p>- Shelter will depend a lot on your local environment, just keep the basic principles of radiation protection in mind. 1st is Distance, 2nd is Mass. If you cant get distance from the radiation source, put mass between you and it. Given that fallout will be dropping from the sky as heavier than air dust, you want to primarily find anything to give you protection against it being blown closer to you horizontally, and maximum distance from whatever roof is over your head. If neither of these are particularly available, prioritise the horizontal wind blown dust, settle for whatever concrete slab building you can find that would afford you some measure of protection from dust blowing in even if the windows and doors were damaged.<p>- Think of it as extreme, unusual, but also unlikely, weather event. You don't want to get "wet" from the dry rain of fallout dust, you also want to be as far away from it as you can, and don't want it getting tracked/blown inside.