FEMA 453 Design Guidance for Shelters and Safe Rooms

Light wood frame structures do not possess significant resistance
to blast loads although larger wood commercial buildings will be
better able to accept these lateral loads than light frame wood
construction. These buildings are likely to suffer heavy damage
in response to 50 pounds of TNT at a stand-off distance of 20 to
50 feet. A shelter would best be located in a basement where the
protection to blast loading would be provided by the surrounding
soil. Large explosive detonations in close proximity to the
building will not only destroy the superstructure, but the effects of
ground shock are likely to fail the foundation walls as well; therefore,
protected spaces should be located interior to the building.
Locating the shelter on the ground floor, for slab on grade structures,
provides the maximum number of floors between occupants
and possible roof debris. Debris catch systems may be installed
beneath roof rafters of single-story buildings; however, the effectiveness
of the debris catch system will be limited if the zone of
roof damage is extensive.
Structural deSign criteria
Figure 2-2
W2 wood commercial
buildings
2- 9