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Item 3: Where the floor is located within the enclosed atrium space
(see Section 404.6), the floor is adjacent to a floor opening and
exposed to other levels of the building. In this situation, the floor
is essentially located within the boundaries of the open atrium
atmosphere and therefore the code is not focused on the vertical
spread of the fire or hot gasses within the space. It is important,
however, to notice that this exception is only applicable to portions
of floors within the atrium enclosure (Section 404.6) and does not
extend to the entire floor level unless the provisions of Exception 3
in Section 404.6 have been used and the volume of the space has
been accounted for in the smoke control system’s design. Figure
107 illustrates which floors may be left without joint protection in
accordance with Item 3.
Item 4: Similar to floors within atriums, which were addressed in
Item 3, this item will eliminate the joint protection requirements
for floors within a mall. Figure 108 illustrates this situation and
shows the floors that are covered by the exception. In applying this
provision, it is important to recognize that the wording limits the
exception to the floors within the mall and not to all floors within the
mall building. By definition and under the provisions of Section 402,
the “mall” is a common pedestrian area within a covered mall or
open mall building.
Item 5: Fire-resistive joint systems are exempted from the floors
of parking garages for a number of reasons. However, parking
garages have an extensive list of other protection requirements in
Section 406. Because provisions in Sections 712.1.10 and 406.5.9
allow various unprotected vertical openings within parking garages,
the elimination of joint protection in these structures will not greatly
compromise them. In addition, based on the amount and type of fuel
loading within a garage, a vehicle fire may be fairly extensive but
often will not spread to adjacent vehicles or areas.