Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
IBC [F] section 910.1.
IBC [F] section 910.1 is amended by adding sections to read as
follows:
910.1.1
Required
venting method. Required smoke and heat venting shall be accomplished
with mechanical smoke exhaust according to Section 910.4.
Exceptions:
1. Calculated engineering design of
mechanical smoke exhaust in accordance with Section 910.5 shall be permitted
for buildings sprinklered throughout.
2. For non-sprinklered buildings, smoke and
heat vents as specified in Section 910.3 shall be permitted.
3. Where approved by the building official,
smoke and heat vents as specified in Section 910.3 shall be permitted in
sprinklered buildings.
910.1.2
Listing. Smoke and heat
vents and mechanical smoke exhaust fans shall be listed for the intended
purpose.
910.1.3
Curtain
boards. When mechanical smoke exhaust is provided in accordance with
Section 910.4 or 910.5, curtain boards are only required at the separation
between areas protected with early suppression fast response (ESFR) sprinklers
and conventional sprinkler systems.
Subp. 2.
IBC [F] section 910.4.
IBC [F] section 910.4 is amended to read as follows:
910.4
Mechanical smoke exhaust.
Mechanical smoke exhaust shall be in accordance with Sections 910.4.1 through
910.4.7.
(Subsections 910.4.1 through 910.4.7 remain unchanged except as
amended in subparts 2a and
3.)
Subp. 2a.
IBC [F] section
910.4.3.1.
IBC [F] section 910.4.3.1 is amended to read as follows:
910.4.3.1
Supply air. Supply air
for exhaust fans shall be sized to provide a minimum of 50 percent of the
required exhaust. Air velocity at each supply air opening shall not exceed an
average of 200 feet per minute when measured 4 feet (1219 mm) in front of the
opening. Openings for supply air shall be uniformly distributed around the
periphery of the area served and be located or ducted to a position not >
one-half the storage height above the floor. Supply air openings shall open
automatically upon operation of the smoke exhaust system and shall not require
a manual action at each supply opening for operation. Supply air openings shall
be kept clear of storage or obstructions to airflow for at least 4 feet (1219
mm) in front of the opening. Supply air openings shall be separated from
exhaust fans and exterior combustibles to prevent introduction of smoke into
the building.
Subp. 3.
IBC [F] section 910.4.4.
IBC [F] section 910.4.4 is amended to read as follows:
910.4.4
Operation. Mechanical
smoke exhaust fans shall be manually activated. Individual manual controls of
each fan unit shall also be provided.
Subp. 4. [Repealed, 44 SR 609 effective
3/31/2020]
IBC [F] section 910.4.5 is amended to read as follows:
910.4.5
Supply air. Supply air
for exhaust fans shall be sized to provide a minimum of 50 percent of the
required exhaust. Air velocity at each supply air opening shall not exceed an
average of 200 feet per minute when measured 4 feet (1219 mm) in front of the
opening. Openings for supply air shall be uniformly distributed around the
periphery of the area served and be located or ducted to a position not more
than one-half the storage height above the floor Supply air openings shall open
automatically upon operation of the smoke exhaust system and shall not require
a manual action at each supply opening for operation. Supply air openings shall
be kept clear of storage or obstructions to airflow for at least fear 4 feet
(1219 mm) in front of the opening. Supply air openings shall be separated from
exhaust fans and exterior combustibles to prevent introduction of smoke into
the building.
Subp.
5.
IBC [F] section 910.5.
IBC [F] section 910.5 is amended, and subsections added, to
read as follows:
910.5
Calculated engineering design of mechanical smoke exhaust. Calculated
engineering design of mechanical smoke exhaust shall be in accordance with
Sections 910.5.1 through 910.5.5.
910.5.1
Methodology. Mechanical smoke exhaust systems shall be designed to
remove smoke after a fire is extinguished and to assist the fire department
during suppression operations or during marginal sprinkler control situations.
They are not considered life safety systems and are not designed for occupant
safety.
910.5.2
Calculation
method. Volumetric flow rate calculations shall demonstrate that the
system will provide at least three air changes per hour for the space required
to be provided with smoke exhaust. When only a portion of a space is used for
high-piled storage requiring smoke exhaust, the volume to be extracted shall be
based on the ceiling height multiplied by the actual gross floor area for
storage.
910.5.3
Operation.
Mechanical smoke exhaust fans shall be manually activated. In addition,
individual manual controls of each fan unit shall also be provided.
910.5.4
Supply air. Supply air
for exhaust fans shall be sized to provide a minimum of 50 percent of the
required exhaust. Air velocity at each supply air opening shall not exceed an
average of 200 feet per minute when measured 4 feet (1219 mm) in front of the
opening. Openings for supply air shall be uniformly distributed around the
periphery of the area served and be located or ducted to a position not more
than one-half the storage height above the floor. Supply air openings shall
open automatically upon operation of the smoke exhaust system and shall not
require a manual action at each supply opening for operation. Supply air
openings shall be kept clear of storage or obstructions to airflow for at least
4 feet (1219 mm) in front of the opening. Supply air openings shall be
separated from exhaust fans and exterior combustibles to prevent introduction
of smoke into the building.
910.5.5
Equipment. Wiring and controls shall be as required in Sections
910.4.5 and 910.4.6. Interlock controls shall be as required in Section
910.4.7. Exhaust fans shall be uniformly spaced and each fan shall have a
maximum individual capacity of 30,000 cfm (850
m3/min).
Subp. 6.
IBC [F] section 910.6.
IBC [F] section 910 is amended by adding a subsection to read
as follows:
910.6
Testing and
maintenance. Mechanical smoke exhaust systems shall be tested and
maintained as required by Sections 910.6.1 through 910.6.4.
910.6.1
Acceptance testing.
Mechanical smoke exhaust systems shall be acceptance tested as required
by Sections 909.18 and 909.19.
910.6.1.1
Controls. For testing purposes, each smoke exhaust system equipped
for automatic activation shall be put into operation by the actuation of the
automatic initiating device. Control sequences shall be verified throughout the
system, including verification of override from the firefighters control panel
when systems are equipped for automatic activation.
910.6.2
Special inspections.
Special inspections for mechanical smoke exhaust shall be conducted according
to Section 909.18.8.
910.6.3
Maintenance. Mechanical smoke exhaust systems, including exhaust
fans, supply air openings and controls, shall be maintained and
unobstructed.
910.6.4
Operational testing. Operational testing of the smoke exhaust
system shall include all equipment such as initiating devices, fans, dampers,
controls, and supply air openings. Mechanical smoke exhaust systems shall be
operated and tested under each control sequence at least annually.