It is not intended to imply that these spaces guarantee safety during a storm, but that they are the safest available in the building. These are some facilities such as lightweight modular houses, offices, and classrooms which must be presumed to be death traps. Know tornado history for the geographic area. Consult the nearest National Weather Service Office. Obtain plans for each floor of the building.
Ideal plans are small, to scale, with sufficient detail.
If the drawings are not available, have someone prepare a simple, accurate drawing of each floor. Check the drawings against the actual building. The space per person depends on the size of the people and their degree of mobility. Small children require only 3 sq. Usually 5-6 sq.