Buildings

Buildings provide considerable protection from fallout. A brick building provides better protection than does a brick veneer building, which is better than that of a frame building. Multiple stories increase protection as well. The interior of a one-story building reduces exposure by 50 percent. A level below ground reduces exposure by 90 percent. Additional levels provide more shielding and increase the overall effectiveness above and below ground.

However, notice in the five-story example that the middle floors provide better shielding than the ground floor because fallout that covers the ground emits gamma radiation along with that on the exterior surfaces of the building. Moving to a higher floor in the building increases the distance from the ground source but, at some point, increases exposure from the source on the rooftop.

The best option is to move to the center of the building away from the exterior walls and below ground, if possible, or to a middle floor above ground. In a detailed illustration of a building, note how the position in the building and surroundings affect the percentage by which exposure is reduced in various locations.