FEMA 453 Design Guidance for Shelters and Safe Rooms

3.4.1 Class 3 Safe Room
Features of the Class 3 Safe Room can be either permanent or
expedient. Guidance for preparing the safe room is presented in
four parts:
m How to tighten the room before an emergency – to
permanently seal unintentional openings
m How to prepare for sealing the room in an emergency – to
temporarily close intentional openings such as ducts, doors,
and windows in an emergency
m How to prepare for rapid deactivation of fans
m How to accommodate the safe use of air conditioning or
heating in protective mode
3.4.1.1 Tightening the Room
m Ceiling-to-wall juncture. Typically, most leakage occurs through
the wall-to-ceiling and wall-to-floor junctures, particularly if
suspended lay-in ceilings are used without a hard ceiling or a
well-sealed roof-wall juncture above the lay-in ceiling. If the
selected room has only a lay-in ceiling between the living space
and attic space, the ceiling should be replaced with one of
gypsum wallboard or other monolithic ceiling configuration.
m Floor-to-wall juncture. A baseboard often obscures leakage
paths at the floor-to-wall juncture, and to seal these leakage
paths may require sealing behind the baseboards. One
approach is to temporarily remove the baseboards and apply
foam sealant in the gap at the floor-to-wall juncture. The
alternate approach is to use clear or paintable caulk to seal the
top and bottom of baseboards and quarter rounds. If there are
electric baseboard heaters, the heaters should be temporarily
removed to seal the wiring penetrations and the gap at the
floor-to-wall juncture.
3- 0 CBR ThReaT pRoTeCTion