I do know that is certain states (US) buildings that are safe for weather conditions that are severe, have a sign designating that on the building. Usually schools and the like.
There was a letter read a while back (this goes back over 5 years) stating that Kingdom Halls were not designated buildings to be used as shelters unless specified.
I figured that was part of their ongoing attempt to have zero liability (or accountability for that matter) toward their flock who gives them all their money.