The clear width of aisles and other
means of egress shall comply with Section 1028.6.1 where
smoke-protected seating is not provided and with Section
1028.6.2 or 1028.6.3 where smoke-protected seating is
provided. The clear width shall be measured to walls, edges of seating and
tread edges except for permitted projections.
1028.6.1
Without smoke
protection. The clear width of the
means of egress
shall provide sufficient capacity in accordance with all of the following, as
applicable:
1. At least 0.3 inch (7.6 mm) of
width for each occupant served shall be provided on stairs
having riser heights 7 inches (178 mm) or less and tread depths 11 inches (279
mm) or greater, measured horizontally between tread
nosings.
2. At
least 0.005 inch (0.127 mm) of additional stair width for each
occupant shall be provided for each 0.10 inch (2.5 mm) of riser height above 7
inches (178 mm).
3. Where egress
requires stair descent, at least 0.075 inch (1.9 mm) of
additional width for each occupant shall be provided on those portions of
stair width having no handrail within a
horizontal distance of 30 inches (762 mm).
4. Ramped means of egress,
where slopes are steeper than one unit vertical in 12 units horizontal
(8-percent slope), shall have at least 0.22 inch (5.6 mm) of clear width for
each occupant served. Level or ramped means of egress, where
slopes are not steeper than one unit vertical in 12 units horizontal (8-percent
slope), shall have at least 0.20 inch (5.1 mm) of clear width for each occupant
served.
1028.6.2
Smoke-protected seating. The clear width of the
means of
egress for
smoke-protected assembly seating shall not
be less than the
occupant load served by the egress element
multiplied by the appropriate factor in Table 1028.6.2. The total number of
seats specified shall be those within the space exposed to the same
smoke-protected environment. Interpolation is permitted between the specific
values shown. A life safety evaluation, complying with NFPA 101, shall be done
for a facility utilizing the reduced width requirements of Table 1028.6.2 for
smoke-protected assembly seating.
Exception: For an outdoor smoke-protected
assembly with an occupant load not greater than 18,000, the
clear width shall be determined using the factors in Section 1028.6.3.
TABLE 1028.6.2 WIDTH OF AISLES FOR SMOKE-PROTECTED
ASSEMBLY
|
TOTAL NUMBER OF
SEATS
IN THE SMOKE- PROTECTED ASSEMBLY OCCUPANCY |
INCHES OF CLEAR PER SEAT
SERVED |
|
Stairs and aisle steps with handrails within 30
inches |
Stairs and aisle steps without handrails
within 30 inches |
Passageways, doorways and ramps not steeper than
1 in 10 in slope |
Ramps steeper
than 1 in 10 in
slope |
| Equal to or less than 5,000 |
0.200 |
0.250 |
0.150 |
0.165 |
| 10,000 |
0.130 |
0.163 |
0.100 |
0.110 |
| 15,000 |
0.096 |
0.120 |
0.070 |
0.077 |
| 20,000 |
0.076 |
0.095 |
0.056 |
0.062 |
| Equal to or greater than 25,000 |
0.060 |
0.075 |
0.044 |
0.048 |
| For SI: 1 inch = 25.4 mm. |
1028.6.2.1
Smoke control.
Means of egress serving a
smoke-protected assembly seating area shall be provided with a
smoke control system complying with Section 909 or natural ventilation designed
to maintain the smoke level at least 6 feet (1829 mm) above the floor of the
means of egress.
1028.6.2.2
Roof height. A
smoke-protected assembly seating area with a roof shall have
the lowest portion of the roof deck not less than 15 feet (4572 mm) above the
highest
aisle or
aisle accessway.
Exception: A roof canopy in an outdoor stadium
shall be permitted to be less than 15 feet (4572 mm) above the highest
aisle or aisle accessway provided that there
are no objects less than 80 inches (2032 mm) above the highest
aisle or aisle accessway.
1028.6.2.3
Automatic sprinklers.
Enclosed areas with walls and ceilings in buildings or structures containing
smoke-protected assembly seating shall be protected with an
approved automatic sprinkler system in accordance with Section
903.3.1.1.
Exceptions:
1. The floor area used for contests,
performances or entertainment provided the roof construction is more than 50
feet (15 240 mm) above the floor level and the use is restricted to low fire
hazard uses.
2. Press boxes and
storage facilities less than 1,000 square feet (93
m2) in area.
3. Outdoor seating facilities where seating
and the means of egress in the seating area are essentially
open to the outside.
1028.6.3
Width of means of egress for
outdoor smoke-protected assembly. The clear width in inches (mm) of
aisles and other
means of egress shall be not
less than the total
occupant load served by the egress element
multiplied by 0.08 (2.0 mm) where egress is by
aisles and
stairs and multiplied by 0.06 (1.52 mm) where egress is by
ramps,
corridors, tunnels or vomitories.
Exception: The clear width in inches (mm) of
aisles and other means of egress shall be
permitted to comply with Section 1028.6.2 for the number of seats in the
outdoor smoke-protected assembly where Section 1028.6.2 permits less
width.
