Building Codes and Barrier-Free Design 267
regulates the length of travel distance from anywhere in a building to the floor or building’s exit. Typi-
cally, however, if the travel distance within a tenant space exceeds 75 feet (22.9m), an additional exit is
required, even if it is not required by the occupant load.
Codes usually allow a room to have a single exit through an adjoining or intervening room, provided
that it affords a direct and unobstructed means of travel to an exit corridor or other exit and as long as
the total stipulated maximum travel distances are not exceeded. Exiting is not permitted through
kitchens, storerooms, rest rooms, closets, or spaces used for similar purposes. Codes normally catego-
rize foyers, lobbies, and reception rooms constructed as required for corridors with a one-hour-rated wall
as intervening rooms, thereby allowing them to be used for exit purposes.
Typically, corridor construction must be of 1-hour fire-resistive construction when serving an occu-
pant load of 10 or more in R-1 and I occupancies and when serving an occupant load of 30 or more in
other occupancies. The 1-hour-rated corridors must extend through the ceiling to the rated floor or roof
above unless the ceiling of the entire story is 1-hour-rated. Where a duct penetrates a fire-rated corri-
dor, a fire damper that closes automatically upon detection of heat or smoke so as to restrict the pas-
sage of flame must be provided.
There are different types of stairs including straight run, curved, winder, spiral, scissor, etc. Exit
stairs should be wide enough to allow for two people to descend side by side with no sudden decrease
in width along the path of travel. Stairs must also adhere to specific code and accessibility requirements
and be constructed in a manner and using materials consistent with the construction type of the build-
ing. Typically, new stairs are required to have a minimum width of 44 inches, an 11-inch tread depth, and
a maximum riser height of 7 inches (Figure 11.6). Handrails and guardrails are likewise regulated.
Figure 11.5 Maximum acceptable distances required to exits (source: Interior Design Reference Manual by
D.K. Ballast).