Commercial Plan Review
Land Use and Environmental Service Agency
(Code Enforcement)
Building Q&A 2009
Fourth Quarter 2009
General:
1. (Q) Table 508.3.3 indicates the separation requirements between occupancy types
for mixed occupancy situations. Occupancies like “B” and “F-1” show a
separation requirement of “N” (No separation requirement) and “B” and “F-2”
as 1-hour if fire sprinklered and 2-hour if not fire sprinklered. Why is the fire
separation requirement less for the “B” and “F-1” separation than for the “B”
and “F-2” separation?
(A) It is true that the separation requirement between “B” and “F-1” should be
greater than for “B” and “F-2” as the code considers “F-1” a greater hazard than
“F-2.” The 2006 NCBC did in fact provide a 3-hour separation between “B” and
“F-1” and a 2-hour separation if the building was fully sprinklered. Table 508.3.3
unfortunately does not tell the whole story. You can provide “B” and “F-1” in the
same building without separation, but the building is then unseparated mixed use
and must be built to the more stringent occupancy type. If you want to design a
building with separated mixed use for “B” and “F-1” you have to go to Table
706.3.9. This is because the code offers no other means of fire-resistance-rating
such separation. Table 706.3.9 is intended to be used to separate like occupancies
such as “B” and “B” into separate fire areas, but it is our only alternative for
separated mixed use fire-resistance-ratings where Table 508.3.3 provides no
rating. For “B” and “F-1” you would use the worst case scenario, and the
required rating would be 3-hours. Note that Table 706.3.9 does not allow a
reduction for fire sprinklers. Note: The 2009 IBC changes the section number
from 706.3.9 to 707.3.9 and adds the following sentence to correct this issue:
“The fire barriers or horizontal assemblies, or both, separating fire areas of mixed
occupancies shall have a fire resistance rating of not less than the highest value
indicated in Table 707.3.9 for the occupancies under consideration. All of the
above was clarified in an interpretation from the NC Department of Insurance
dated June 19, 2009.
2. (Q) Does Code Section 1008.1.3.3 apply to all sliding doors or just those entering
a building or tenant suite required for egress in and out of the space?
(A) Refer to Code Section 1008.1.2 for door swing. Egress doors shall be sidehinged swinging. Exception 1: Private garages, office areas, factory and storage
areas with an occupant load of 10 or less. This exception would allow for a sliding
door in an office area with an occupant load of 10 or less. Exception 6 in other
than Group H occupancies, horizontal sliding doors complying with Section
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1008.1.3.3 are permitted in a means of egress. Section 1008.1.3.3 requires that
the sliding door comply with 8 criteria with the first being: The door shall be
power operated and shall be capable of being operated manually in the event of a
power failure. Thus, a 400 sq. ft. conference room could have a sliding door but
the door must comply with all 8 items in 1008.1.3.3.
3. (Q) If an accessory room, (such as a conference room, or a break room) of a
tenant space has an exit access door opening directly onto the exit access
corridor; is the occupant load of the accessory area required to be included as
part of the total occupant load of the primary space in determining the egress
requirements?
(A) No, provided the accessory room (conference room, etc.) occupant load does
not require egress through the primary space. The primary space must comply
with the egress requirements for number and size of exits as well as remoteness of
exits and may or may not utilize the accessory room in the exit path to satisfy the
required remoteness of exits for the primary tenant space.
4. (Q) A tenant space may require two or more remotely located exits per 1015.1
and 101015.2 because of the space size, length of exit travel and/or number of
occupants. If the limited length of exit access corridor does not provide sufficient
distance to satisfy the remoteness rule along the corridor, is it acceptable to
separate the space into two smaller tenant type areas (each small enough to
require only one exit) and treat the two smaller areas as if they were separate
tenants each required to provide single exits, thereby eliminating the need for
remoteness?
(A) Yes, provided all of the following conditions are met:
a) Each space shall comply as a single exit space meeting Table 1015.1
b) The communicating access door must be located to meet the
remoteness rule for the space and marked with an exit sign on each
side
c) The division wall shall be constructed consistent with the tenant
separation requirements for the building, but not less than smoke-tight
floor to ceiling
d) Hard wired smoke detectors shall be installed in the corridor within 15
feet of the tenant space corridor doors with alarms that can be heard
throughout the tenant space
5. (Q) Many listed and approved fire stop systems require that an item penetrating
the rated wall or floor (pipes, conduit, wiring, etc.) be rigidly supported on both
sides of the wall or floor being penetrated. What is required for these penetrating
items to meet the “rigidly supported” condition?
(A) Section 712, 712.3.1.1 and 712.4.1.1.1 require that when a building service
system (electrical, plumbing, mechanical) penetrates a fire rated assembly it
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shall be protected by an approved fire stop system. The approved fire stop
system must be installed consistent with the requirements of the listing. To
ensure the penetrating item does not move at the point of penetration causing
the fire stop system to be compromised, it requires adequate (or rigid)
support on each side of the penetration. Minimum support for electrical,
plumbing, and mechanical systems is addressed by various tables in the
respective volumes of the North Carolina State Building Code. Unless the
support requirements are specifically addressed by the approved listed test;
building service systems, which are supported in accordance with the Code,
shall be deemed adequately/rigidly supported. The support system should be
designed based on the premise the fire stop system (point of penetration)
provides no support.
6. (Q) Are secondary or miscellaneous structural members, such as a steel wall
frame member, header or masonry lintel required to be fire protected if they are
welded or bolted to a rated structural frame?
(A) Yes, a minimum of 24 inches of the secondary member will need to be
protected at the connection to the structural frame. Table 601 specifies the
required fire protection of the structural frame based on the type of
construction. Footnote (a) defines the structural frame as the columns,
girders, beams, trusses and spandrels having direct connections to the columns
and bracing members designed to carry gravity loads. The concern is that
although a secondary structural member and its performance may not have a
direct effect on the stability of the primary building frame, it could allow heat
to transfer through the direct connection and cause the premature failure of the
structural frame. Due to this potential heat transfer problem, in addition to
structural members requiring full protection, any secondary structural
members with direct connections to the structural frame shall be protected a
minimum of 24 inches from the connection.
Fourth Quarter 2009