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SECTION
910 SMOKE AND HEAT VENTS
[F]
910.1 General. Where required by this code or otherwise
installed, smoke and heat vents, or mechanical smoke exhaust
systems, and draft curtains shall conform to the requirements
of this section.
Exceptions:
1. Frozen
food warehouses used solely for storage of Class I and II
commodities where protected by an approved automatic sprinkler
system.
2.
Where areas of buildings are equipped with early suppression
fast-response (ESFR) sprinklers, automatic smoke and heat
vents shall not be required within these areas.
[F]
910.2 Where required. Smoke and heat vents shall be installed
in the roofs of one-story buildings or portions there of occupied
for the uses set forth in Sections 910.2.1 through 910.2.3.
[F]
910.2.1 Group F-1 or S-1. Buildings and portions thereof
used as a Group F-1 or S-1 occupancy having more than 50,000
square feet (4645 m2) in undivided area.
Exception: Group S-1 aircraft
repair hangars.
[F]
910.2.2 High-piled combustible storage. Buildings and
portions thereof containing high-piled combustible stock
or rack storage in any occupancy group in accordance with
Section 413 and the International
Fire Code.
[F]
910.2.3 Exit access travel distance increase. Buildings
and portions thereof used as a Group F-1 or S-1 occupancy
where the maximum exit access travel distance is increased
in accordance with Section 1016.2.
[F]
910.3 Design and installation. The design and installation
of smoke and heat vents and draft curtains shall be as specified
in Sections 910.3.1 through 910.3.5.2 and Table 910.3.
[F]
910.3.1 Design. Smoke and heat vents shall be listed
and labeled to indicate compliance with UL 793.
[F]
910.3.2 Vent operation. Smoke and heat vents shall be
capable of being operated by approved automatic and manual
means. Automatic operation of smoke and heat vents shall
conform to the provisions of Sections 910.3.2.1 through
910.3.2.3.
[F] 910.3.2.1 Gravity-operated drop-out vents.
Automatic smoke and heat vents containing heat-sensitive
glazing designed to shrink and drop out of the vent opening
when exposed to fire shall fully open within 5 minutes
after the vent cavity is exposed to a simulated fire,
represented by a time-temperature gradient that reaches
an air temperature of 500°F (260°C) within 5 minutes.
[F] 910.3.2.2 Sprinklered buildings. Where installed
in buildings provided with an approved automatic sprinkler
system, smoke and heat vents shall be designed to operate
automatically.
[F] 910.3.2.3 Nonsprinklered buildings. Where installed
in buildings not provided with an approved automatic sprinkler
system, smoke and heat vents shall operate automatically
by actuation of a heat-responsive device rated at between
100°F (38°C) and 220°F (104°C) above ambient.
Exception: Gravity-operated drop-out vents complying with
Section 910.3.2.1
[F]
910.3.3 Vent dimensions. The effective venting area
shall not be less than 16 square feet (1.5 m2)
with no dimension less than 4 feet (1219 mm), excluding
ribs or gutters having a total width not exceeding 6 inches
(152 mm).
[F]
910.3.4 Vent locations. Smoke and heat vents shall be
located 20 feet (6096 mm) or more from adjacent lot lines
and fire walls and 10 feet (3048 mm) or more from fire barrier
walls. Vents shall be uniformly located within the roof
area above high-piled storage areas, with consideration
given to roof pitch, draft curtain location, sprinkler location
and structural members.
[F]
910.3.5 Draft curtains. Where required by Table
910.3, draft curtains shall be provided in accordance
with this section.
Exception: Where areas of buildings are equipped with
ESFR sprinklers, draft curtains shall not be provided within
these areas. Draft curtains shall only be provided at the
separation between the ESFR sprinklers and the conventional
sprinklers.
[F]
910.3.5.1 Construction. Draft curtains shall be constructed
of sheet metal, lath and plaster, gypsum board or other
approved materials which provide equivalent performance
to resist the passage of smoke. Joints and connections shall
be smoke tight.
[F]
910.3.5.2 Location and depth. The location and minimum
depth of draft curtains shall be in accordance with Table
910.3.
[F]
910.4 Mechanical smoke exhaust. Where approved by the
fire code official, engineered mechanical smoke exhaust shall
be an acceptable alternate to smoke and heat vents.
[F]
910.4.1 Location. Exhaust fans shall be uniformly spaced
within each draft -curtained area and the maximum distance
between fans shall not be greater than 100 feet (30 480
mm).
[F] 910.4.2 Size. Fans
shall have a maximum individual capacity of 30,000 cfm (14.2
m3 /s). The aggregate capacity of smoke exhaust
fans shall be determined by the equation:
C = A x 300
(Equation 9-10)
where:
C = Capacity of mechanical
ventilation required, in cubic feet per minute (m3
/s).
A = Area of roof vents
provided in square feet (m2) in accordance
with Table 910.3.
[F]
910.4.3 Operation. Mechanical smoke exhaust fans shall
be automatically activated by the automatic sprinkler system
or by heat detectors having operating characteristics equivalent
to those described in Section 910.3.2. Individual manual
controls of each fan unit shall also be provided.
[F]
910.4.4 Wiring and control. Wiring for operation and
control of smoke exhaust fans shall be connected ahead of
the main disconnect and protected against exposure to temperatures
in excess of 1,000 °F (538°C) for a period of not less than
15 minutes. Controls shall be located so as to be immediately
accessible to the fire service from the exterior of the
building and protected against interior fire exposure by
fire barriers having a fire-resistance rating not less than
1 hour.
[F]
910.4.5 Supply air. Supply air for exhaust fans shall
be provided at or near the floor level and shall be sized
to provide a minimum of 50 percent of required exhaust.
Openings for supply air shall be uniformly distributed around
the periphery of the area served.
[F]
910.4.6 Interlocks. In combination comfort air-handling/smoke
removal systems or independent comfort air-handling systems,
fans shall be controlled to shut down in accordance with
the approved smoke control sequence.
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