DEPARTMENT OF DEVELOPMENT SERVICES
BUILDING DIVISION
Ronald L. Lynn, Director/Building Official
Gregory J. Franklin, Assistant Director
Neil Burning, Manager of Plans Examination
PROPOSED ASSEMBLY USES IN
EXISTING OPEN PARKING
GARAGES
The Clark County Building Division has
identified a number of concerns
regarding the proposed use of an
existing open parking garage for any
assembly uses.
PARKING STRUCTURE
Mandalay Bay Concert
ASSEMBLY
EVENTS
Fremont Street Concert
STRUCTURAL
The Building Code requires a parking garage to
meet a minimum structural design standard of 40
psf for live loads, whereas the minimum live load
design standard for buildings used for assembly
purposes is 100 psf, or 250% greater.
If a stage or platform is provided in the assembly
use, the minimum live load required for the stage
or platform is 125 psf or 313% greater than what is
required for parking garages.
STRUCTURAL
CONTINUED
All buildings must also meet specific occupancy category
requirements for structural design. These categories are
assigned by the intended use of the building. A parking garage
is assigned as a Category II building, while a building used for
public assembly is classified as a Category III building.
A Category III classification requires the building to meet more
stringent design standards for resisting seismic, snow and
wind loads. Therefore, the minimum structural design for
buildings used for an assembly use must resist a 25% greater
seismic load, a 10% greater snow load, and a 15% greater
wind load than what is required for the structural design of a
parking garage.
These significant differences in minimum structural design
requirements represents a potential life-safety risk to the
building occupants, if an existing parking garage was allowed
to be used for assembly purposes.
MEANS OF EGRESS
There are also substantial differences in the means
of egress requirements for buildings used for
assembly versus a building used as an open garage,
including the following:
MEANS OF EGRESS
CONTINUED

Travel Distance
In a typical parking garage (non-sprinkled) the occupants are
permitted to travel a distance of 300 feet in order to reach an
exit.
However, a building used for public assembly is limited to a
maximum travel distance of 200 feet; 250 feet if the building
has fire sprinklers throughout.
This travel distance restriction is due to the fact that it takes
much more time for the occupants in assembly buildings to
exit due to the much greater number and density of the
occupants.
MEANS OF EGRESS
CONTINUED

Size and Number of Exits
The occupant load for a parking garage is required to be
based on an occupant load factor of 200 gross square feet
per person.
In contrast, the required occupant load factor for a building
used for public assembly is 15 net square feet per person.
This means the number of occupants in buildings used for
public assembly is approximately thirteen (13) times greater
than a typical open parking garage having the same floor
area.
Also, due to the much larger number of occupants, many
more exits are required to allow the occupants to safely
evacuate the assembly building.
MEANS OF EGRESS
CONTINUED

Capacity (Width) of Exit Stairs
Since buildings used for assembly have thirteen (13) times
the number of occupants than a parking garage, the
dimensional size or widths of the exit stairs must also be
much greater than those used in parking garages.
MEANS OF EGRESS
CONTINUED

Exit Stair Enclosures
All stairs serving a building used for public assembly are
required to be enclosed within two (2)-hour fire-resistant-rated
shaft enclosures. In contrast, stairways that serve an open
parking garage are allowed to be unprotected and completely
open.
MEANS OF EGRESS
CONTINUED

Ceiling Height
A building used as a parking garage is allowed a clear ceiling
height of only 7 feet in the vehicle and pedestrian traffic
areas.
A building used for public assembly must maintain a
minimum ceiling height of 7 feet 6 inches.
FIRE PROTECTION
SYSTEMS
Automatic fire sprinkler systems are not required to be
installed in open parking garages, regardless of the
height or area of the garage.
However, the Building Code requires an automatic fire
sprinkler system to be installed throughout a building
used for assembly, if the building exceeds 5,000
square feet in area or if the number of occupants
exceeds 300 people.
Sprinklers are always required if the assembly use is
located on an elevated floor level or within a
basement not having direct access to the exterior of
the building.
FIRE PROTECTION
SYSTEMS
CONTINUED
Fire alarms and other fire alarm/occupant notification
systems are not required for open parking garages.
However, a fire alarm system is required for any
building used for public assembly, if the number of
occupants exceeds 300. If the number of occupants
exceeds 1,000, then the building would also be
required to have an emergency voice/alarm
communication system installed throughout.
PLUMBING FIXTURE
COUNTS
A minimum number of plumbing
fixtures such as water closets,
lavatories, drinking fountains,
and service sinks, is not required
for open parking garages.
However, the Building Code
requires a large number of
plumbing fixtures in buildings
used for assembly due to the
extremely large number of
building occupants.
ACCESSIBILITY
Handicap accessibility requirements of the
Building Code must also be met for any
building used for public assembly.
These requirements include an accessible
means of egress, accessible routes
throughout
the
building,
accessible
entrances, accessible bathroom facilities,
accessible drinking fountains and unisex
toilets and bathing rooms.
ACCESSIBILITY
CONTINUED
There are significant differences between the
accessible means of egress requirements for an
assembly use and those required for an open
parking garage.
Areas of refuge are not required at exit stairways or
elevators serving open parking garages.
Buildings used for assembly must have an
accessible means of egress. This requires that the
exit stairways contain an area of refuge (an enlarged
floor-level landing).
Similarly, to be considered part of an accessible
means of egress, an elevator must be accessed
from either an area of refuge or from a horizontal
exit.
ELEVATORS
Enclosed elevator lobbies are not required for
elevators serving open parking garages.
However, if an assembly use is added to an existing
open parking garage, then the elevator is required to
be enclosed in a fire-resistance rated shaft enclosure
and if the elevator shaft connects more than three
stories, then an enclosed elevator lobby would be
required at each floor.
SPECIAL REQUIREMENTS
There are special electrical, mechanical and
plumbing design requirements for any building
used for public assembly.
The most significant requirements are for the
required smoke control systems and for
emergency and standby power. These emergency
power systems are necessary to ensure the
smoke control systems work if the building
should lose power and also to have sufficient
lighting to allow the occupants to exit the building.
MIXED-USE PROVISIONS
FOR A NEW BUILDING
The Building Code does contain “special
provisions” for new buildings designed for
mixed uses; such as buildings having separate
areas within the same building to be used for
both an open parking garage and for assembly.
These “special provisions” are subject to
specific conditions. There are two different
design approaches as to how the mixedoccupancies are to be separated:
MIXED-USE PROVISIONS
FOR A NEW BUILDING
CONTINUED

Non-separated Occupancies
Under this design approach, fire-resistance rated separations
are not required between the different uses (occupancies).
Each occupancy in the building is individually classified and
code requirements are applicable to each portion of the
building based on the occupancy classification of that space;
however, the most restrictive applicable provisions Section
403 (high-rise requirements) and Chapter 9 (fire protection
systems) must be used for the entire building.
Further, the allowable height and area of the building must be
based on the most restrictive allowances of the occupancy
groups under consideration.
MIXED-USE PROVISIONS
FOR A NEW BUILDING
CONTINUED

IBC Section 508.3.3 – Separated Occupancies
Under this design approach, each occupancy in the
building is individually classified, and the individual
occupancies must be separated from the adjacent
occupancies by fire-resistance rated walls/floors in
accordance with the Building Code. Each fire area
then must comply with the applicable code
requirements based on the occupancy classification
of that portion of the building.
SUMMARY
The Clark County Building Division has
significant concerns regarding the potential
risks to the life safety and welfare of the
building occupants, if a parking garage
building is not brought into full compliance
with all current code requirements for
buildings used for public assembly.