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Debunking a myth on assembly space doors

Blog Post created by rcote Employee on Jun 16, 2015

MYTH:  Any assembly occupancy room with an occupant load of more than 50 must
have a second egress door.

 

Assembly occupancy exits are typically accessed via a
corridor or lobby and take the form of enclosed exit stairs or doors directly
to the outside. The floor or story might have to be arranged to provide access
to a minimum of two exits.

 

The door or doors from the assembly room to the corridor or lobby are
rarely exit doors; they are most often exit access doors. NFPA 101®, Life Safety Code® contains no
requirement that an assembly room with an occupant load of more than 50 be
provided with a minimum of two exit access doors. Such rooms are often provided
with a second exit access door in order not to violate the common path of
travel limitation. Common path is the initial portion of the exit access (and
the initial portion of the overall travel distance to the nearest exit) for
which the occupants are steered in one direction without a choice of paths
leading to different exits.

 

Assembly occupancy rooms or areas with an occupant load of more than 50
persons are permitted only 20 ft (6.1 m) of common path of travel. For most
room locations and arrangements, a second exit access door from the room can be
positioned to provide occupants with a second travel path while still within
the room. The presence of the second exit access door can reduce what would
otherwise be an excessive common path of travel to one that is within the
permitted distance.

 

Figure 1 depicts a meeting room that is classified as an assembly
occupancy as the occupant load exceeds 50 persons. The 20-ft common path of
travel limitation forces the presence of a second exit access door from the
space.

 

Figure 1. Assembly occupancy meeting room requiring two exit access
doors so as not to exceed the allowable common path of travel.

 

Figure 2 depicts a meeting room that is not classified as an assembly
occupancy as the occupant load is fewer than 50 persons. The room is considered
incidental to the remainder of the floor’s occupancy classification of
business. The building is sprinklered so that the allowable common path of
travel is 100 ft (30 m). The room arrangement, with a single door to an exit
access corridor that provides for travel to two different exits, complies with
the common path of travel limitation so as not to require a second exit access
door from the room.


Figure 2. Meeting room requiring only a single exit access door as the
allowable common path of travel is met.

Outcomes