FEMA 453 Design Guidance for Shelters and Safe Rooms

Table 1-4: ISC CBR Levels of Protection
Level of
Protection
Low
Medium
High
For Biological/
Radiological
Contaminants
use minimum
efficiency reporting
value (MerV) 13
filter or functional
equivalent.
use high-efficiency
particulate air (HePa)
filter or functional
equivalent.
use HePa filter or
functional equivalent.
For
Chemical/
Radiological
Additional Considerations Class
none none 3
use gas
absorber for
outside air.
use gas
absorber for
outside air
and return
air.
design for future detection
technology
stairway pressurization
system should maintain
positive pressure in stairways
for occupant refuge, safe
evacuation, and access
by firefighters. the entry
of smoke and hazardous
gases into stairways must be
minimized.
Locate utility systems at least
1 m ( 0 ft) from loading
docks, front entrances, and
parking areas.
design for future detection
technology
stairway pressurization
system should maintain
positive pressure in stairways
for occupant refuge, safe
evacuation, and access
by firefighters. the entry
of smoke and hazardous
gases into stairways must be
minimized.
Locate utility systems at least
1 m ( 0 ft) from loading
docks, front entrances, and
parking areas.
1-18 design considerations
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