Download 2009 IBC® Mixed Occupancies

2009 IBC Mixed Occupancies
Purpose
The goal of this course
is to provide processes
for determining code
requirements for
accessory,
nonseparated and
separated occupancy
options established in
IBC Section 508.
2009 IBC® Mixed
Occupancies
Based on the 2009 International Building Code® (IBC®)
Mixed-occupancy Building
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Objectives
Objectives
After completing this seminar, you will be able to:
 Define the concept for addressing mixed-occupancy buildings.
 Identify the three methods that are available for regulating mixedoccupancy buildings.
 Describe the relationship of occupancy classification, allowable
height, allowable area and occupancy separation to mixedoccupancy buildings.
 Follow a seven-step process for applying the Accessory
Occupancies provisions.
 Identify incidental accessory occupancies and understand how
they differ from mixed-occupancy conditions.
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2009 IBC Mixed Occupancies
 Apply the separation and/or fire protection requirements
for incidental accessory occupancies.
 Follow a four-step process for applying the nonseparated
occupancies provisions.
 Follow a five-step process for applying the separated
occupancies provisions.
 Apply the mixed-occupancy methods to a multiple-story building.
 Evaluate the differences between the three methods, including
the relative advantages and disadvantages for each method.
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2009 IBC Mixed Occupancies
Explanation of Icons
 These events may be identified by the following icons
throughout this training:
Module 1
Mixed Use and
Occupancy
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Mixed Use and Occupancy Scope
Section 508
Definition
 A mixed-occupancy condition occurs where two or more
distinct occupancy classifications are determined to exist
in the same building.
 Under such circumstances, the designer has available
several different methodologies to address the mixedoccupancy building.
The provisions of Section 508 address two main concepts:
 Nonseparated Occupancies regulated by
Sections 508.2, 508.3 and 508.4
 Incidental Accessory Occupancies regulated by
Section 508.2.5
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Mixed Occupancies
Incidental Accessory Occupancies
 Two or more distinct occupancy classifications result in the
mandatory use of Section 508.
 Floor areas listed in Table 508.2.5 are designated
as Incidental Accessory Occupancies.
 One or more of the options below must be applied to the building
under consideration for mixed-occupancy conditions:
 Incidental Accessory Occupancies are uniquely regulated for:
 Accessory Occupancies regulated by Section 508.2.
 Nonseparated Occupancies regulated by Section 508.3.
 Separated Occupancies regulated by Section 508.4.
 Occupancy classification, and
 Separation, fire protection or a combination of both.
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Mixed Occupancies: Location
Mixed Occupancies
Section 508.1
 Two or more occupancies within a building
 Provisions of Section 508 address the relationship between two
individual occupancy groups adjacent to each other in a building;
vertically or horizontally.
 Provisions of Section 508 must be applied.
 Adjoining occupancies are regulated by the IBC.
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Mixed Occupancies:
Scope, Section 508.1
Mixed Occupancies:
Scope, Section 508.1
 Three methods established in Section 508 to
address mixed-occupancy buildings include:
The scope of Section 508 is limited to four fundamental issues:
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Occupancy classification;
Allowable building height;
Allowable building area; and
Separation.
 Accessory Occupancies.
 Nonseparated Occupancies.
 Separated Occupancies.
 Method for determining maximum allowable size, height and area
identified for each option.
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Mixed Occupancies:
Scope, Section 508.1
 Occupancy Classification
 Proper occupancy classifications determined
 Two or more different occupancies, Section 508
 Allowable Building Height and Area
 Final analysis for allowable height and area cannot be done
until one of the three mixed-occupancy options has been
chosen.
 Separation
 Separation is not required between occupancies.
 Some degree of fire-resistance-rated separation is mandated to
isolate one occupancy from another.
Module 2
Occupancy
Classification
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Classification of Occupancies
Section 302
Classification of Occupancies
Section 302
 Classification is essential to the proper application
of the IBC.
 Structure classified according to the function or functions for which
it is intended.
 Buildings classified prior to the application of Section 508
regulating mixed-occupancy conditions.
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A
Assembly
I
Institutional
B
Business
M
Mercantile
E
Educational
R
Residential
F
Factory/Industrial
S
Storage
H
High Hazard
U
Utility
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Classification of Occupancies
Section 302
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Use and Occupancy Classification:
Chapter 3
 Chapter 3 provides an extensive listing of various uses
and their corresponding occupancy classifications.
 IBC created a means to differentiate occupancies.
 If two or more distinct occupancy groups present, the provisions of
Section 508.3 will apply.
 26 specific occupancy classifications organized into 10 broad
groupings.
 Occupancy classification regulates the hazards associated with a
buildings expected use.
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Section 302.1 General
Section 302.1
General
 Structures classified into one or more occupancies in
accordance with their intended uses.
 If the use is not specifically identified in Chapter 3, it must be
classified with the occupancy it most nearly resembles.
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A
B
E
F
Assembly
Business
Educational
Factory and Industrial
H
I
M
R
Hazardous
Institutional
Mercantile
Residential
S
U
Storage
Utility
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Section 303.1
Assembly Group A
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Section 303.1
Assembly Group A
 Assembly Group A includes a gathering together for:
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 The following are general characteristics of
Assembly Group A occupancies:
Civic functions.
Social activities.
Religious functions.
Food or drink consumption.
Awaiting transportation.
 Densely occupied areas.
 Moderate to large occupant loads.
 Moderate fuel load.
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Section 303.1
Assembly Group A
Section 303.1
Assembly Group A
 Group A-1: Viewing performing arts or motion pictures.
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 Group A-2: Food or drink consumption.
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Movie theaters.
Multiple-theater complexes.
Performance theaters.
Symphony and concert halls.
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Banquet halls.
Night clubs.
Restaurants.
Taverns and bars.
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Section 303.1
Assembly Group A
Section 303.1
Assembly Group A
 Group A-3: Worship, recreation or amusement and other
assembly uses not classified elsewhere in Group A.
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 Group A-4: Indoors sports events and activities with spectator
seating.
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Community halls.
Dance halls (not including food or drink consumption).
Gymnasiums (without spectator seating).
Places of religious worship.
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Arenas.
Pools.
Skating rinks.
Tennis courts.
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Section 303.1
Assembly Group A
Section 304.1
Business Group B
 Group A-5: Viewing or participating in outdoor activities.
 Business Group B occupancy includes the use of
a building or structure, for office, professional or
service-type transactions, including storage of
records.
 Amusement park structures.
 Grandstands and bleachers.
 Stadiums.
 Examples:
 Auto showrooms, car washes.
 Banks.
 Clinics, ambulatory healthcare facilities.
 College classrooms.
 Outpatient facilities.
 Testing and research laboratories.
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Section 305.1
Education Group E
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Section 306.1
Factory Group F
 The occupancy of six or more persons at any one time
for education purposes through the 12th grade.
 Includes the use of a building or structure for assembling,
disassembling, fabricating, finishing, manufacturing, packaging,
repair or processing operations that are not otherwise classified as
a Group H High-hazard occupancy or Group S Storage occupancy.
 The day care of toddlers and infants ages 2 ½ years and under
may also be classified as a Group E occupancy under three
conditions as established in the Exception to Section 308.5.2
(Group I-4 occupancies).
 Divided into two different categories:
 Group F-1: Moderate Hazard
 Group F-2: Low Hazard
A Group E classification is possible where:
 The number of toddlers/infants is more than 5 but no more
than 200 children;
 The rooms in which the children are being cared for are
located on the level of exit discharge; and
 Each of these child care rooms has an exit door directly to the
exterior.
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Section 306.1
Factory Group F
Section 306.1
Factory Group F
 Group F-1: Moderate Hazard (those uses not specifically classified
as a Group F-2 Low-hazard occupancy).
 Aircraft plant.
 Bakeries.
 Dry cleaners.
 Furniture plants.
 Printing and publishing.
 Group F-1 occupancies typically include those
Factory/Industrial operations that utilize or involve combustible
materials.
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 Group F-2: Low Hazard (the fabrication or manufacturing of
noncombustible materials not involving a significant fire hazard).
 Foundries.
 Glass products.
 Gypsum.
 Ice.
 Metal fabrication.
 Nonalcoholic beverages.
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Section [F] 307.1
High Hazard Group H
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Section [F] 307.1
High Hazard Group H
 Conditions where a Group H classification is not required:
 Typically include, among others, the use of a building or structure,
or a portion thereof, that involves the manufacturing, processing,
generating or storage of materials that constitute a physical or
health hazard in quantities in excess of those allowed in control
areas as set forth in Tables 307.1(1) and 307.1(2).
 Buildings used for application of flammable and combustible
liquids, aerosol manufacture or storage and the storage of black
powder.
 Cleaning establishments utilizing solvents under
specific conditions.
 Closed systems housing flammable or combustible liquids or
gases utilized for the operation of machinery or equipment.
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Section [F] 307.1
High Hazard Group H
Section [F] 307.1
High-hazard Group H, Table 307.1(1)
 Conditions where a Group H classification is not required:
 Materials for agricultural purposes on the premises.
 Refrigeration systems.
Table 307.1(1),
Page 26-27
 Stationary batteries used for emergency power or uninterrupted
power supply (UPS).
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Section [F] 307.1
High-hazard Group H, Table 307.1(1)
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Section [F] 307.1
High-hazard Group H, Table 307.1(2)
Table 307.1(1),
Page 26-27
Table 307.1(2),
Page 28
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Section [F] 307.3
Group H-1 Structures
Section [F] 307.4
Group H-2 Structures
 Buildings and structures that contain materials that
present a deflagration hazard or a hazard from accelerated
burning must be classified as Group H-2.
 Buildings and structures that contain materials that present
a detonation hazard must be classified as Group H-1.
 Such materials include, but are not limited to:
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 Such materials include, but are not limited to:
Explosives,
Unclassified detonable,
Organic peroxide,
Class 4 oxidizers,
Class 3 detonable,
Class 4 unstable (reactive) materials and detonable
pyrophoric materials.
 Class I, II or IIIA flammable, or combustible liquids that
are used or stored in normally open containers or
systems; or in closed containers or systems pressurized
at more than 15 psi,
 Combustible dusts,
 Flammable cryogenic liquids,
 Flammable gases,
 Class I organic peroxides,
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Section [F] 307.4
Group H-2 Structures
Section [F] 307.5
Group H-3 Structures
 Buildings and structures that contain materials that support
combustion or present a physical hazard.
Such materials include, but are not limited to:
 Class 3 oxidizers used or stored in normally open
containers or systems, or in closed containers or
systems pressurized at more than 15 psi,
 Nondetonable pyrophoric liquids, solids and gases,
 Class 3 nondetonable unstable (reactive) materials and
 Class 3 water reactive materials.
 Such materials must include, but are not limited to:
 Class I, II, IIIA flammable or combustible liquids that are
used or stored in normally closed containers or systems
pressurized at less than 15 psi;
 Combustible fibers;
 Consumer fire works, 1.4G (Class C, common);
 Oxidizing cryogenic liquids;
 Flammable solids,
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Section [F] 307.5
Group H-3 Structures
Section [F] 307.6
Group H-4 Structures
 Buildings and structures that contain materials that are
health hazards.
Such materials include, but are not limited to:
 Class II and III organic peroxides;
 Class 1 and 2 oxidizers;
 Class 3 oxidizers used or stored in normally
closed containers or systems pressurized at less
than 15 psi;
 Oxidizing gases;
 Class 2 unstable (reactive) materials; and
 Class 2 water reactive materials.
 Such materials must include, but not be limited to:
 Corrosives,
 Highly toxic materials and
 Toxic materials.
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Section [F] 307.7
Group H-5 Structures
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Section 308.1
Institutional Group I
 Semiconductor fabrication facilities and comparable research and
development areas in which hazardous production materials (HPM)
are used and the aggregate quantity of materials are in excess of
those listed in Table 307.1(1) and 307.1(2).
 Include the use of building or structure, or a portion
thereof, in which people are:
 Provided with care or live in a supervised environment;
 Harbored for medical treatment or other care due to
physical limitations caused by health or age; or
 Detained for penal or correction purposes or in which the
liberty of the occupants is restricted.
 Areas must be designed and constructed in accordance with
Chapter 4 (Special Detailed Requirements Based on Use and
Occupancy), Section 415.8.
 Institutional occupancies shall be classified as Group I-1, I-2, I-3 or
I-4.
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Section 308.2
Institutional Group I-1
Section 308.3
Institutional Group I-2
 Includes buildings, structures or parts thereof housing
more than 16 persons, on a 24-hour basis, who live in a supervised
environment that provides personal care.
 Includes buildings and structures used for medical,
surgical and psychiatric care on a 24-hour basis of persons who
are not capable of self-preservation.
 Occupants must be able to respond to an emergency situation
without assistance.
 Examples:
 24-hour child care for more than five children 2½
years of age or less.
 Detoxification facilities.
 Hospitals.
 Intermediate-care facilities.
 Skilled-care nursing homes.
 Mental hospitals.
 Examples:
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Assisted living facilities.
Drug rehabilitation facilities.
Convalescent facilities.
Group homes.
Halfway houses.
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Section 308.4
Institutional Group I-3
Section 308.4
Institutional Group I-3
 Includes buildings and structures that are inhibited by
five persons under restraint or security and incapable of selfpreservation due to security reasons.
 Buildings of Group I-3 must be classified into one
of five conditions:
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Condition 1 – Free movement—interior/exterior—Group R.
Condition 2 – Free movement interior only.
Condition 3 – Free movement within smoke compartment.
Condition 4 – Limited movement—remote locks—up to 10
manual release locks.
 Condition 5 – Restricted movement—manual release locks.
 Examples:
 Jails.
 Prisons.
 Reformatories.
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Section 308.5
Institutional Group I-4
Section 308.5
Institutional Group I-4
 Examples:
 Buildings and structures occupied by persons of any age receiving
custodial care outside of the home by nonfamily members for less
than 24-hours per day.
 Adult day care:
 More than five persons.
 Supervision and personal care.
 Less than 24 hours.
 Five or fewer persons must be classified as Group R-3 or comply
with the IRC.
 Child day care:
 More than five persons.
 Supervision and personal care.
 Less than 24 hours.
 2½ years of age or less.
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Section 308.5
Institutional Group I-4
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Section 309.1
Mercantile Group M
 Child care facilities may be classified as Group E
occupancies where:
 Used for the display and sale of merchandise.
 Mercantile occupancies include, but are not limited to:
 The number of children 2½ years of age or less exceeds 5 and
is less than 100;
 The rooms where such children are cared for are located on the
level of exit discharge; and
 Each of these child care rooms has an exit door directly to the
exterior.
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Department stores.
Drug stores.
Markets.
Motor fuel-dispensing facilities (including the
canopy).
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Section 310.1
Residential Group R
Section 310.1
Residential Group R
 Occupancies classified as Group R-2 include two types of
residential living arrangements where the occupants are primarily
permanent in nature:
 The use of a building, or a portion of a building, for
sleeping purposes when not classified as Institutional Group I.
 Usually has a high fuel load and high fire risk.
 Residential Group R includes:
 Group R-1: Residential occupancies for transient lodging,
including hotels and motels.
 Occupants are there for a short time period.
 Occupants not familiar with exits.
 Usually no cooking facilities.
 “Transient” considered as occupancy for no more
than 30 days.
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 Apartment houses, nontransient hotels and motels,
vacation timeshare properties and similar buildings
having more than two dwelling units.
 Dormitories, fraternity and sorority houses, nontransient
boarding houses, convents, monasteries and similar
buildings considered as congregate living facilities,
live/work units.
 Where a congregate living facility (nontransient) has an occupant
load of 16 or less, it can be classified as a Group R-3 occupancy.
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Section 310.1
Residential Group R
Section 310.1
Residential Group R
 Occupancies classified as Group R-3 include those residential uses
where the occupants are primarily permanent in nature and the use
is not classified as Group R-1, R-2, R-4 or I.
 Group R-3 occupancies include:
 Adult and child care facilities that are within
a single-family home are permitted to comply with the IRC.
 Group R-4: Residential occupancies for residential care or assisted
living.
 One- and two-family dwellings that fall outside of the
scope of the IRC;
 Adult and child care facilities that accommodate 5 or
less persons of any age for less than 24 hours;
 Congregate living facilities (transient) having an
occupant load of 16 or less; and
 Congregate living facilities (nontransient) having an
occupant load of 16 or less.
 More than five and less than 16 occupants (excluding
staff).
 Permitted to comply with IRC provided building is
sprinklered.
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Section 311.1
Storage Group S
Section 311.2
Moderate-hazard Storage, S-1
 Group S-1: Buildings occupied for storage uses that are not
classified as Group S-2 or Group H including, but not limited to,
storage of the following:
 The use of a building or structure or portions thereof,
for storage not classified as a hazardous occupancy.
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Aerosols, Level 2 and 3.
Aircraft hangers.
Books and paper in rolls or packs.
Cardboard.
Cloth and clothing.
Furniture.
Lumber.
Motor vehicle repair garages complying with the
maximum allowable quantities of hazardous materials.
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Section 311.3
Low-hazard Storage, S-2
Section 312.1
Utility and Miscellaneous Group U
 Buildings used for storage of noncombustible materials.
Storage uses include:
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 Buildings and structures not classified in any specific occupancy
must be constructed, equipped and maintained to conform to the
requirements of this code.
Beverages up to 16-percent alcohol.
Cement in bags.
Dairy products in nonwaxed coated paper containers.
Empty cans.
Glass.
Gypsum board.
Meats.
Metal cabinets.
Parking garages (open or enclosed).
 Examples:
 Agricultural buildings.
 Barns.
 Carports (to be open on at least two sides in accordance
with Section 406.1.3).
 Fences more than 6 foot (1829 mm) high.
 Grain silos.
 Private garages.
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Allowable Building Heights
and Areas, Section 503
 Determination of which method applies.
Module 3
Allowable Building Size
 Differences in how the allowable height is regulated.
 Provisions related to allowable height and area be understood.
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Allowable Building Heights
and Areas, Table 503
Allowable Building Heights
and Areas, Table 503
Table 503.
Page 80
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Table 503.
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Height Modifications Section 504
Allowable Height Increase
Height Modifications Section 504
Allowable Height Increase
 The height values in Table 503 are permitted
to be increased by:
 Group R occupancies equipped with an approved automatic
sprinkler system in accordance with Section 903.3.1.2 (NFPA 13R),
the height values are permitted to be increased by:
 A maximum of one story.
 A maximum of one story.
 A maximum additional height of 20 feet (6096 mm).
 These increases are permitted in addition to the area increase
in accordance with Section 506.2.
 A maximum additional height of 20 feet (6096 mm).
 Up to a limit of four stories and 60 feet (18 288 mm).
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Allowable height increase example
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Example
 Type VA building, Group B occupancy.
 Table 503 Tabular Height: 3 stories; 50 feet (15 240 mm)
maximum height.
 Equipped with NFPA 13 sprinkler system:
 Allowable one story increase to four stories.
 Allowable 20 foot (6096 mm) height increase to 70
feet
(21 336 mm) maximum height.
 Area increase is also permitted.
(without sprinklers)
Group B, Type VA
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Area Modifications
Section 506
Area Modifications
Section 506
 Two methods by which the allowable area limits set
forth in Table 503 may be increased:
 The permitted increases are added to the tabular
allowable area in the following manner:
 Aa= {At + [At x If] + [At x Is]}, where
 Automatic sprinkler system protection (Is) in accordance with
Section 506.3.
 Open frontage (If) in accordance with Section 506.2.
 Aa = Allowable area per story (square feet)
 At = Tabular area per story in accordance with Table 503
(square feet)
 If = Area increase factor due to frontage in accordance with
Section 506.2
 Is = Area increase factor due to sprinkler protection in
accordance with Section 506.3
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Allowable Area Increase: Sprinkler
Protection Section 506.3
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Area Increase for Sprinklers:
Table 503 and Section 506.3
 Allowable area of a fully sprinklered (NFPA 13 only) building:
 Additional 200 percent (IS=2), multiple-story building
 Additional 300 percent (IS=3), single-story building
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Given: One-story, Type VA building housing Group B occupancy
Determine: Maximum allowable area if fully sprinklered
Tabular area:
 The area increase for sprinkler protection is not permitted under
the following conditions:
N
 Group H-1 occupancies.
 Group H-2 and H-3 occupancies (where a mixedoccupancy building contains a Group H-2 and/or H-3
occupancy, the sprinkler increase is only applicable to
those portions that are not classified as Group H-2 or H3).
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Sprinkler increase: 54,000 sq. ft. (300% increase)
Total
allowable area:
(per story)
72,000 sq. ft.
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18,000 sq. ft. (Table 503)
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Area Increase for Sprinklers:
Table 503 and Section 506.3
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Allowable Area Increase: Frontage
Section 506.2
 To receive an area increase for frontage purposes, a building must:
Given: Two-story, Type VA building housing Group B occupancy
Determine: Maximum allowable area if fully sprinklered
Tabular area:
N
 Adjoin or have access to a public way, and
 Have more than 25 percent of its perimeter on a public way or
open space that is a minimum of 20 feet in width.
18,000 sq. ft. (Table 503)
Sprinkler increase: 36,000 sq. ft. (200% increase)
Total
allowable area:
(per story)
54,000 sq. ft.
Workbook page 27
Workbook page 28
77
Allowable Area Increase:
Frontage Section 506.2
78
Allowable Area Increase:
Frontage Section 506.2
 The frontage increase is calculated in the following manner:


Given: One-story, Type VA building housing Group B occupancy
Determine: Maximum frontage increase permitted
If= [F/P – 0.25] W/30, where
If = (F/P – 0.25) W/30
If = Area increase due to frontage
F = Building perimeter that fronts on a minimum 20-foot-wide
public way or open space
P = Perimeter of entire building
W = Width of public way or open space per Section 506.2.1
(20 feet minimum)
N
F = 420'
P = 840'
W = 35' at west, 40' at south
If = (420/840– 0.25) W*/30
= (.50– 0.25)(30*/30)
= .25 (1.0)
If = 0.25 or 25%
 Where W is 30 feet or greater, a value of 30 feet is to be used in
calculating the frontage increase.
*30' to be used for W
Workbook page 28
Workbook page 28
79
2009 IBC Mixed Occupancies
80
20
2009 IBC Mixed Occupancies
Frontage Increase:
Weighted Average Section 506.2.1
Frontage Increase:
Weighted Average Section 506.2.1


 Where W is greater than or equal to 20 feet, but less
than 30 feet, the weighted average method is used when
calculating the frontage increase. For those open spaces or public
ways that have a minimum width of 30 feet or more, a value of 30
feet is to be used in the calculation.
Given: One-story Type VA building housing Group B occupancy
Determine: Maximum frontage increase permitted
If = (F/P – 0.25) W/30
N
F = 420' P = 840'
W = 35' at west, 40' at south
W = [25(220)+ 30*](200)=27.4
= (0.50– 0.25)(27.4/30)
= 0.25 (0.91)
If =0.23
=23%
*30' to be used for W
Workbook page 29
Workbook page 29
81
Open Space Limits
Section 506.2.2
Area Increases
Sections 506.1, 506.2 and 506.3
 Open space used for a frontage increase to allowable
area must be:
 The maximum allowable area for a building one story
in height is based on:
 Located on the same lot as the building under consideration or
dedicated for public use.
 Accessed from a street or approved fire lane.
 The tabular values from Table 503, plus
 The sprinkler increase, if applicable, based on Section 506.3,
plus
 The frontage increase, if applicable, based on Section 506.2.
Workbook page 29
Workbook page 30
83
2009 IBC Mixed Occupancies
82
84
21
2009 IBC Mixed Occupancies
Area Increases
Sections 506.1, 506.2 and 506.3


Area Increases
Sections 506.1, 506.2 and 506.3


Given: One-story, Type VA building housing Group B occupancy
Determine: Maximum allowable area if fully sprinklered
Given: Two-story Type VA building housing Group B occupancy
Determine: Maximum allowable area per story if fully sprinklered
Tabular area:
Tabular area:
18,000 sq. ft. (Table 503)
18,000 sq. ft. (Table 503)
Sprinkler increase: 36,000 sq. ft. (200% increase)
N
Sprinkler increase: 54,000 sq. ft. (300% increase)
N
Total
allowable area:
(per story)
4,500 sq. ft.
Total
allowable area:
(per story)
25%
4,500 sq. ft.
25%
Total allowable area: 58,500 sq. ft. Additive
Total allowable area: 76,500 sq. ft. Additive
Workbook page 30
Workbook page 30
85
Area Determination: Multiple-story
Buildings Section 506.4
86
Area Determination: Multiple-story
Buildings Section 506.4


 Where a single-occupancy building has two or more stories above
grade plane, the maximum allowable area of the building is
determined by multiplying the allowable area of the first story by:
 Two times, for buildings with two stories above grade plane; or
 Three times, for buildings with three or more stories above
grade plane.
Tabular area:
N
 The allowable area per story is limited to that determined by
Section 506.1 for the occupancies on each story.
18,000 sq. ft. (Table 503)
Sprinkler increase:
36,000 sq. ft. (200% increase)
Frontage increase:
4,500 sq. ft.
Total allowable
area per floor:
58,500 sq. ft. Additive
25%
Total allowable
area for the building: 175,500 sq. ft. 3x
Workbook page 31
Workbook page 31
87
2009 IBC Mixed Occupancies
Given: Four-story, Type VA building housing Group B occupancy
Determine: Maximum allowable area if fully sprinklered
88
22
2009 IBC Mixed Occupancies
Area Determination: Multiple-story
Buildings Section 506.4
Unlimited Area Buildings
Section 507
 Allowable area for a mixed-occupancy multiple-story building varies
based on the mixed-occupancy methods used from Section 508.
 Provisions of Section 507 permit the floor area
of complying buildings to be unlimited for
allowable area purposes.
The limitations include:
 Accessory Occupancies: Based upon general provisions
of Section 508.2.
 Nonseparated Occupancies: Based upon most restrictive provisions
for each occupancy.
 Separated Occupancies: Based upon sum of ratios for each
occupancy in accordance with Section 508.4.2, where the sum of the
ratios on all floors shall not exceed:




 Multiply by two for two-story buildings; or
 Multiply by three for buildings three stories and higher.
Workbook page 31
Applicable only to certain occupancies.
Maximum height of one or two stories.
Automatic sprinkler system protection.
Significant open space surrounding the
building.
Workbook page 32
89
Unlimited Area Buildings
Section 507
90
Unlimited Area Buildings
Section 507
 Section 507.3 addresses the most common application
of unlimited area provisions. Under this provision, a building may
have an unlimited allowable area if it complies with four
fundamental conditions:
 Mixed-occupancy building can also be regulated under the
unlimited area provisions.
 Provisions of Section 508 must be reviewed for compliance.
 Group B, F, M or S occupancy (also Group A-4 of other than
Type V construction).
 Maximum of one story in height.
 Automatic sprinkler system provided throughout.
 Surrounded and adjoined by minimum 60-foot yards and/or
public ways.
Workbook page 32
Workbook page 32
91
2009 IBC Mixed Occupancies
92
23
2009 IBC Mixed Occupancies
Separation:
Fire Barriers Section 707
Separation: Fire Barriers
Section 706
 Under the Incidental Accessory Occupancy and the
Nonseparated Occupancy a fire-resistance-rated separation
is not required.
 Separations must be fire barriers constructed in
accordance with Section 707, and/or horizontal assemblies in
accordance with Section 712.
 Provisions of Section 706 address:
 Under the Separated Occupancies, reference for any fireresistance-rated separation comes from Table 508.4.






 Indicates the minimum required separation between adjacent
occupancies.
 Some require no separation.
 Some require separation with the minimum level of fire
resistance.
Workbook page 33
Continuity.
Openings.
Penetrations.
Joints.
Ducts and air transfer openings.
Supporting construction.
Workbook page 33
93
Mixed Occupancies:
Overview Section 508.1
Mixed Occupancies:
Overview Section 508.1
 There are four key components that regulate
mixed-occupancy buildings:




Occupancy classification.
Allowable height.
Allowable area.
Separation.
Accessory
Occupancies
Section 508.2
Nonseparated
Occupancies
Section 508.3
Separated
Occupancies
Section 508.4
Occupancy
Classification
Individually classified
Individually classified
Individually classified
Allowable Area
For accessory
occupancy, based on
allowable area of main
occupancy
For building, based
on most restrictive of
occupancies under
consideration
For building,
determined such that
the sum of the ratios
of actual area divided
by allowable area
cannot exceed 1.0
Allowable
Height
For accessory
occupancy, based on
tabular values of Table
503
For building, based
on most restrictive of
occupancies under
consideration
For building, based on
general provisions of
Section 503.1
Separation
No separation
required between
occupancies except
for incidental
accessory
occupancies
No separation
required between
occupancies
Fire-resistance-rated
separation as required
by Table 508.4
Table 508.2.5,
Page 85
 The three mixed-occupancy methods differ from the other based
upon one or more of the four components.
Workbook page 34
95
2009 IBC Mixed Occupancies
94
Workbook page 34
96
24
2009 IBC Mixed Occupancies
Mixed Occupancies:
Three Methods Section 508.1
 Section 508.1 mandates that one of the three methods must be
applied where a mixed-occupancy exists.
 Determination of the method depends on the owner/designer.
 Building function
 Construction costs
 Design flexibility
Module 4
Accessory Occupancies
 Building official verifies compliance of the selected method with the
proper code requirements.
Workbook page 35
97
Mixed Occupancies:
Three Methods Section 508.1
Mixed Occupancies: Use of Multiple
Methods Section 508.1
 Section 508.1 exceptions:
 Special provisions of Section 509 superseded Section 508.1.
 Mixed-occupancy conditions are prohibited for Group H-1, H-2
and H-3 occupancies required to be in a detached building by
Table 415.3.2.
 Specific requirements for live/work units in Section 419.
 Owner/Designer may choose to use more than one method.
 Relationship between multiple pairs of occupancies should be
individually analyzed.
Workbook page 35
Workbook page 35
99
2009 IBC Mixed Occupancies
98
100
25
2009 IBC Mixed Occupancies
Accessory Occupancies: Method 1
Section 508.2
Accessory Occupancies: Method 1
Section 508.2
 Must be subsidiary to the main occupancy of the building or to a
portion.
 Limited to 10 percent of the floor area of the story located.
 Examples of occupancies that may be considered as subsidiary to
the main occupancy:
 Group A-2 employee lunchroom within a Group S-1
warehouse.
 Group A-3 training room in a Group B office building.
 Group M showroom within a Group F-1 manufacturing
building.
 Group R-3 manager’s dwelling unit within a Group S-1
self-storage facility.
 Floor area cannot exceed the tabular allowable floor areas
established by Table 503.
 When more than one occupancy is under consideration, the
aggregate area of such occupancies are used to determine
compliance.
Workbook page 37
Workbook page 37
101
Accessory Occupancies
Example
102
Accessory Occupancies: Occupancy
Classification Section 508.2.2
 Must be assigned to an occupancy group established in
Chapter 3 based upon unique characteristics.
 The spaces of the building considered as accessory occupancies
must meet all code requirements applicable to the specific
occupancy classification.
 Example:
 The means of egress requirements for an accessory
occupancy are based upon the occupancy classification
of the accessory occupancy, not that of the main
occupancy.
Workbook page 38
Workbook page 39
103
2009 IBC Mixed Occupancies
104
26
2009 IBC Mixed Occupancies
Accessory Occupancies: Allowable
Area and Height Section 508.2.3
Accessory Occupancies: Allowable
Area and Height Section 508.2.3
 Allowable area of any accessory occupancy is based on
the main occupancy.
 Combined area of the main occupancy and accessory occupancy
cannot exceed that permitted by Section 503.1 for the main
occupancy.
Workbook page 39
Workbook page 39
105
Accessory Occupancies: Allowable
Area and Height Section 508.2.3
Accessory Occupancies: Separation
Section 508.2.4
 Height is limited to that set forth in Table 503 without
any height increase for a sprinklered building.
 Application of the accessory occupancy method will result
in no physical or fire-resistance-rated separation being mandated.
Workbook page 40
Workbook page 40
107
2009 IBC Mixed Occupancies
106
108
27
2009 IBC Mixed Occupancies
Accessory Occupancies:
A Seven-Step Process

Accessory Occupancies:
A Seven-Step Process
Seven steps to follow when using accessory
occupancy method:
4. Verify that the floor area of the accessory occupancy
(or aggregate accessory occupancies where
applicable) does not exceed the tabular floor area
(without area increases of Section 506) set forth in
Table 503 for the building’s type of construction.
1. Determine the various occupancy classifications that
are found within the building.
2. Verify that any occupancy group under consideration
as an accessory occupancy is subsidiary to the major
occupancy of the building.
5. Determine the maximum allowable floor area of the
building based upon the allowable floor area of the
major occupancy, including any applicable increases
for building frontage and/or an automatic sprinkler
system.
3. Verify that the floor area of the accessory occupancy
(or aggregate accessory occupancies where
applicable) does not exceed 10 percent of the floor
area of the story in which it is located.
Workbook page 41
Workbook page 41
109
Accessory Occupancies:
A Seven-Step Process
110
Accessory Occupancies:
Applying the Process
6. Determine the maximum allowable height of the
accessory occupancy based upon the tabular values
of Table 503, without any height increase for
sprinklers in
accordance with Section 504.2.
Given: A four-story office building with a large meeting
room (occupant load of 78) on the second floor. The
building is fully sprinklered, Type IIB
constructionandqualifies for a 75 percent frontage
increase for allowable area. Each story of the building
contains 45,000 square feet and the floor area of the
meeting room is 1,170 square feet (109 m2). It is intended
that no fire-resistant occupancy separation be provided
between the meeting room and the remainder of the
building.
7. Apply all other code requirements to each portion of
the building based upon the individual occupancy
classification of the space.
Determine: If the mixed-occupancy conditions comply
with the requirements for accessory occupancies.
Workbook page 41
Workbook page 42
111
2009 IBC Mixed Occupancies
112
28
2009 IBC Mixed Occupancies
Accessory Occupancies:
Applying the Process
Accessory Occupancies:
Applying the Process

Workbook page 42
Solution:
1. Determine the various occupancy classifications that are found
within the building.
2. Verify that any occupancy group under consideration as an
accessory occupancy is subsidiary to the major occupancy of
the building.
3. Verify that the floor area of the accessory occupancy does not
exceed 10 percent of the floor area of the story in which it is
located.
4. Verify that the floor area of the accessory occupancy does not
exceed the tabular floor area (without area increases of Section
506) set forth in Table 503 for the building’s type of
construction.
Workbook page 43
113
114
Accessory Occupancies:
Applying the Process
5. Determine the maximum allowable floor area of the
building based upon the allowable floor area of the major
occupancy.
6. Determine the maximum allowable height of the accessory
occupancy based upon the tabular values of Table 503.
7. Apply all other code requirements to each portion of the
building based upon the individual occupancy classification of
the space.
Module 5
Incidental Accessory
Occupancies
Workbook page 43-44
115
2009 IBC Mixed Occupancies
116
29
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies:
Identification Section 508.2.5
Incidental Accessory Occupancies:
Identification Section 508.2.5
 Rooms or spaces that pose risks but not addressed by the
provisions of the code for the general occupancy group.
 Considered to be incidental accessory occupancies and regulated
according to their hazard level.
Workbook page 45
Workbook page 45
Examples of spaces considered incidental use
areas:
 Furnace rooms where any piece of equipment
exceeds a 400,000 Btu per hour input rating.
 Paint shops (where located within a Group F
occupancy, paint shops are not regulated as
incidental use areas).
 Laboratories in Group E and I-2 occupancies.
 Vocational shops located in Group E
occupancies.
 Laundry rooms over 100 square feet (9.29
m2).
 Waste and linen collection rooms over 100
square feet (9.29 m2).
117
Incidental Use Areas:
Identification Section 508.2.5
118
Incidental Accessory Occupancies:
Classification, Section 508.2.5
 Areas identified in Table 508.2.5 regulated under the mixedoccupancy provisions of Section 508.3.3.
 Classification is consistent with the location.
 For example:
 No specific definition for an incidental use area.
 A chemistry lab/classroom in a high school building,
although considered as an incidental accessory
occupancy, is intended to be classified as a part of the
Group E occupancy.
Workbook page 45
Workbook page 46
119
2009 IBC Mixed Occupancies
120
30
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies:
Classification, Section 508.2.5
Separated or
Protected per
Table 508.2.5
Incidental Accessory Occupancies:
Separation and/or Protection
Section 508.2.5:
 Unoccupied incidental accessory occupancies.
 Presence of combustible or hazardous material.
 Isolating remainder of building from incidental accessory
occupancies:
 Fire-resistance-rated separation.
 Automatic fire-extinguishing system (automatic sprinkler).
Separated or
Protected per
Table 508.2.5
 Fire-separation and fire-extinguishing system are mandated in
limited cases.
Workbook page 48
Workbook page 47
121
Incidental Accessory Occupancies:
Separation and/or Protection
122
Incidental Accessory Occupancies:
Identification Table 508.2.5
 Incidental accessory occupancies listed in Table 508.2.5
 Selected because of the increased risk of hazard to other areas
in the building.
 Fire separation and fire protection requirements provide
safeguards.
Workbook page 48
Workbook page 48
123
2009 IBC Mixed Occupancies
Table 508.2.5,
Page 85
124
31
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies:
Identification Table 508.2.5
Incidental Accessory Occupancies:
Separation Table 508.2.5.1
 Fire-resistance-rated separations required by
Table 508.2.5; fire barriers and/or horizontal assemblies.
 Ensure that incidental accessory occupancies are isolated.
Horizontal
Assembly per
Section 712 if a
floor system
Table 508.2.5,
Page 85
Fire barrier per
Section 707
Workbook page 49
Workbook page 49
125
Incidental Accessory Occupancies:
Fire Protection, Section 508.2.5.2
126
Incidental Accessory Occupancies:
Fire Protection, Section 508.2.5.2
 Table 508.2.5 allows for the installation of an automatic
fire-extinguishing system.
 Incidental Accessory Occupancies:
 Resistant walls.
 Regulated doors.
 Enclosed rooms.
Workbook page 50
Workbook page 50
127
2009 IBC Mixed Occupancies
128
32
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies:
The Process
Incidental Accessory Occupancies
Is the use under consideration
listed as an incidental accessory
occupancy by Table 508.2.5?
1. 300-square-foot (27.87 m2) tenant laundry room in
apartment building.
*Fire separation is
required for:
Yes
No
Provisions of
Section 508.2.5
do not apply
Is the incidental accessory
occupancy to be protected by an
automatic fire-extinguishing
system?
Yes
No
Separate the incidental
accessory occupancy with fire
barriers and/or horizontal
assemblies.
1. Hydrogen cut-off
rooms.
2. Incinerator rooms.
3. Paint shops.
4. Group I-3 cells.
5. Group I-2 waste
and linen
collection rooms.
6. Stationary storage
battery systems.
7. Rooms containing
fire pumps.
Separate the incidental accessory
occupancy with construction
capable of resisting the passage of
smoke*.
Workbook page 51

1-hour or automatic fire-extinguishing system (Table
508.2.5).
Workbook page 52
129
Incidental Accessory Occupancies
130
Incidental Accessory Occupancies
2. Woodworking shop in high school.

3. 90-square-foot (8.361 m2) waste collection
room in a hotel.
1-hour or automatic fire-extinguishing system (Table
508.2.5).
Workbook page 52
No special requirements (Table 508.2.5).
Workbook page 52
131
2009 IBC Mixed Occupancies

132
33
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies
Incidental Accessory Occupancies
5. 80-square-foot (7.432 m2) linen collection
room in a nursing home.
4. Paint shop (not a Group H) in a repair garage.
 2 hours, or 1 hour and automatic fire-extinguishing
system (Table 508.2.5).

Workbook page 52
1 hour (Table 508.2.5).
Workbook page 52
133
Incidental Accessory Occupancies
134
Incidental Accessory Occupancies
6. Paint shop (not a Group H) in a factory.

7. Group H hydrogen cut-off room in a fully
sprinklered Group F-1 manufacturing building.
1 hour (Section 416.2).

Workbook page 53
Workbook page 53
135
2009 IBC Mixed Occupancies
2 hours (Table 508.4).
136
34
2009 IBC Mixed Occupancies
Incidental Accessory Occupancies
8. Furnace room where the largest piece of equipment has
a 300,000 British thermal units per hour (Btu/h)
(87,921.32 watts per hour) input rating.

Module 6
Nonseparated
Occupancies
No special requirements (Table 508.2.5).
Workbook page 53
137
Nonseparated Occupancies:
Method 2 Section 508.3
138
Nonseparated Occupancies:
Method 2 Section 508.3
 Lack of any requirements for a fire-resistance-rated
separation between adjacent occupancies.
 Some degree of flexibility through compliancy with the “worst-case”
conditions.
 Fundamental concept:
 If the building is designed in part to address the most hazardous
conditions then a fire-resistant separation is not necessary.
 This worse case application of the provision eliminates the need for
any separation.
Workbook page 55
Workbook page 55
139
2009 IBC Mixed Occupancies
140
35
2009 IBC Mixed Occupancies
Nonseparated Occupancies:
Classification Section 508.3.1
Nonseparated Occupancies:
Classification Section 508.3.2.1
 Based upon the general provisions of Section 302.1.
 Individually classified based on the use of space.
 Most restrictive applicable provisions of Chapter 9 regulating fireprotection systems apply to the entire building, not just the specific
occupancy.
Workbook page 56
Workbook page 56
141
Nonseparated Occupancies: Allowable
Area and Height Section 508.3.2
142
Nonseparated Occupancies: Allowable
Area and Height Section 508.3.2
 The maximum allowable height and area of a building is
based upon the most restrictive allowances for the occupancy
groups under consideration.
 The most restrictive allowable area is applied to the entire building.
 Same limitation is applied to the building’s height.
Workbook page 57
Workbook page 57
143
2009 IBC Mixed Occupancies
144
36
2009 IBC Mixed Occupancies
Nonseparated Occupancies: Allowable
Area and Height Section 508.3.2
Nonseparated Occupancies:
Separation Section 508.3.3
 Application of this method will result in no physical or fireresistance-rated separation between the nonseparated
occupancies.
 Benefits of this method:
 Separation element permitted, but not required, and
 Redistribution of floor area between occupancies anticipated.
 Exception:
 Cannot be used where Group H occupancies are involved.
Workbook page 57
Workbook page 58
145
Nonseparated Occupancies:
Separation Section 508.3.3
146
Nonseparated Occupancies:
A Four-Step Process

When using the nonseparated occupancies
method, the following four steps should follow:
1. Determine the occupancy classifications present in the
building.
2. Apply the most restrictive fire protection requirements
of Chapter 9 to the entire building.
3. Determine the maximum allowable height and area for
each of the occupancies under consideration and apply
the most restrictive of each to the entire building.
4. Apply all other code requirements to each portion of
the building based upon the individual occupancy
classification of the space.
Workbook page 58
Workbook page 59
147
2009 IBC Mixed Occupancies
148
37
2009 IBC Mixed Occupancies
Nonseparated Occupancies:
Applying the Process
Nonseparated Occupancies:
Applying the Process
 Given: A three-story, Type IIB building containing
assembly, business and mercantile uses as shown on the
following slide. The building is fully sprinklered and does
not qualify for any frontage increase for allowable area
purposes. Each story is 24,000 square feet (2230 m2) in
floor area.
 Determine: If the building complies when the
nonseparated-occupancies method is used to regulate the
mixed-occupancy condition.
Workbook page 60
Workbook page 60
149
Nonseparated Occupancies:
Applying the Process
Nonseparated Occupancies:
Applying the Process
Solution:
1. Determine the occupancy classifications present in
the building.
Solution:
2. Apply the most restrictive fire protection
requirements of Chapter 9 to the entire building.
3. Determine the maximum allowable height and area
for each of the occupancies under consideration,
and apply the most restrictive of each to the entire
building.
Workbook page 60
Group A-2
Group B
Group M
Allowable Height
(number of stories)
3
4
3
Allowable Area per
Story (square feet)
28,500
69,000
37,500
Allowable Building
Area (square feet)
85,500
207,000
112,500
4. Apply all other code requirements to each portion of the
building based upon the individual occupancy classification of
the space.
Workbook page 61
151
2009 IBC Mixed Occupancies
150
152
38
2009 IBC Mixed Occupancies
Separated Occupancies:
Method 3 Section 508.4
 Only one of the three methods where a fire-resistance-rated
occupancy separation is required under mixed-occupancy
conditions.
Module 7
Separated Occupancies
 Table 508.4 should be referenced to determine the degree of fire
resistance that is mandated.
Workbook page 63
154
153
Separated Occupancies:
Method 3 Section 508.4
Fire Areas
Section 901.7
 This method differs from the other occupancies in three
other ways:
 The fire protection requirements of Chapter 9 are to be
applied individually based on the occupancies in the
building.
 The allowable height for each occupancy is based on
the type of construction of the building in accordance
with Section 503.1.
 The allowable area of the building is based on the sum
of the ratios where the actual floor area of each
occupancy divided by the allowable floor area of each
occupancy is not to exceed 1.0 (unity formula).
Workbook page 63
 No relationship between mixed-occupancy provisions of Section
508 and the fire area concept in Section 903.2 for automatic
sprinkler systems.
 Compliance with any of the occupancies does not relieve
responsibility to comply with Section 901.7 and Table 707.3.9
regarding the proper separation of fire areas.
Workbook page 64
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2009 IBC Mixed Occupancies
 Based on an approach to limit the spread of fire in a building.
 Created through the use of fire barriers and/or horizontal
assemblies.
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2009 IBC Mixed Occupancies
Fire Areas
Section 901.7
Separated Occupancies: Occupancy
Classification Section 508.4.1
Occupancy separation not required
per separated occupancies and
Table 508.4
 This method also requires that the occupancies be classified
individually based upon their specific functions.
 Classification consistent with the provisions of Section 302.1
Fire area separation of 3 hours
required by Section 903.2.4 and
Table 707.3.9
 Requirements for means of egress, fire protection systems, fire
alarm systems, plumbing facilities and all other provisions are to be
applied individually to the various occupancy groups in the building.
Occupancy separation of 2 hours
required per separated
occupancies and Table 508.3.3
Fire area separation of 3 hours
required by Sections 903.2.1.3 and
903.2.9, and Table 707.3.9
Workbook page 64
Workbook page 65
157
Separated Occupancies: Occupancy
Classification Section 508.4.1
158
Separated Occupancies:
Allowable Area Section 508.4.2
 When a mixed-occupancy building is regulated under the
provisions of Section 508.4 for separated occupancies, the unity
formula is used in the determination of allowable area per story.
Minimum 1-hour F.R.R.
separation per Table 508.4
 Compliance for allowable area can only be achieved where the
sum of the ratios of actual floor area divided by allowable floor
areas for each of the occupancies involved does not exceed 1.
The formula can be expressed as:
Workbook page 65
Workbook page 66
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Separated Occupancies:
Allowable Area Section 508.4.2
Separated Occupancies:
Allowable Area Section 508.4.2
 Example:
 a1, a2 and a3 represent the actual floor areas for the individual
occupancies.
 Given: A one-story, 78,000-square foot (7246 m2), fully
sprinklered building with three occupancy groups as
shown. The building is of Type IIB construction and
adjoins two public ways that qualify for a 25-percent
frontage increase.
 A1, A2 and A3 represent the maximum allowable areas for the
same respective occupancies.
 Calculation is applied regardless of any required separation.
 Determine: If the building complies with the allowable
area limitations based on separated occupancies is.
Workbook page 66
Workbook page 67
161
Separated Occupancies:
Allowable Area Section 508.4.2
162
Separated Occupancies:
Allowable Area Section 508.4.2
 Solution:
Workbook page 67
Workbook page 67
163
2009 IBC Mixed Occupancies
164
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2009 IBC Mixed Occupancies
Separated Occupancies:
Allowable Height Section 508.4.3
Separated Occupancies:
Allowable Height Section 508.4.3
 Each individual occupancy in a multiple-story, mixed-occupancy
building is regulated for height independently based on Section
503.1.
No separation required
per Table 508.4
 Maximum height for each occupancy is limited by the type of
construction set forth in Table 503.
 Measured from the grade plane.
 If a building has an automatic sprinkler system, an increase of
one story and 20 feet (6096 m2) may be available under Section
504.2.
Workbook page 68
Workbook page 68
165
Separated Occupancies: Separation
Section 508.4.4
166
Separated Occupancies: Separation
Section 508.3.3.4
 The requirements for a fire-resistance-rated separation
between adjacent occupancies vary.
 The requirements are established in Table 508.4.
Table 508.4,
Page 86
 Fire barriers and/or horizontal assemblies are to be utilized in the
complete separation of adjacent incompatible occupancies.
Workbook page 69
Workbook page 69
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Separated Occupancies:
A Five-Step Process

Workbook page 70
Separated Occupancies:
Applying the Process
There are five basic steps to follow when using
the separated occupancies method:
1. Determine the various occupancy classifications that
occur within the building.
2. Determine the minimum required fire-resistance rating
between adjacent occupancies.
3. Verify that the building does not exceed the maximum
allowable area for the type of construction involved.
4. Verify that the location of the occupancies do not
exceed their maximum allowable height based on the
building’s type of construction.
5. Apply all other code requirements to each portion of
the building based upon the individual occupancy
classification of the space.
 Given: A 30,000-square-foot (2787 m2), one-story building
of Type VB construction contains offices, manufacturing
operations and flammable gas storage rooms (Group H-2)
as shown on the following slide. The building is fully
sprinklered and qualifies for a 50 percent allowable area
increase for frontage. There is no fire-resistant separation
between the office area and the manufacturing area. A 1hour fire barrier separates the hazardous storage rooms
from other areas of the building.
 Determine: If the building complies the provisions for
separated occupancies.
Workbook page 71
169
Separated Occupancies:
Applying the Process
170
Separated Occupancies:
Applying the Process

Solution:
1. Determine the various occupancy classifications that occur
within the building.
2. Determine the minimum required fire-resistance rating between
adjacent occupancies.
3. Verify that the building does not exceed the maximum
allowable area for the type of construction involved.
Workbook page 71
Workbook page 71-72
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2009 IBC Mixed Occupancies
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43
2009 IBC Mixed Occupancies
Separated Occupancies:
Applying the Process
Separated Occupancies:
Applying the Process
4. Verify that the location of the occupancies do not
exceed their maximum allowable height based on the building’s
type of construction.
5. Apply all other code requirements to each portion of the
building based upon the individual occupancy classification of
the space.
Workbook page 72
Workbook page 72
173
Mixed Occupancies: Allowable Height
and Area for Multi-story Buildings
Accessory Occupancies
 Application of Section 508 for mixed-occupancy is
consistent for both single-story and multiple-story buildings.
 Regulated on a story by story basis.
 Multiple-story, mixed-occupancy building:
 All three methods available.
 Evaluation of the mixed-occupancy conditions is expanded.
Workbook page 73
 When the entire building is regulated for allowable floor area, the
general requirements of Section 506.5 are applicable.
Workbook page 73
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2009 IBC Mixed Occupancies
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176
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2009 IBC Mixed Occupancies
Nonseparated Occupancies
Separated Occupancies
 The maximum allowable height and area of the building
will be based upon the most restrictive allowances for the
occupancies under consideration.
 General height and area limitations of Chapter 5 will apply.
 An occupancy shall not be located higher than permitted
by Table 503 with an increase of one story and 20 feet (6096 mm)
permitted based on the installation of an automatic sprinkler
system.
 A variation of the unity formula of Section 508.4.2 that is applied on
a per-story basis is applied to the total building.
Workbook page 74
Workbook page 75
177
Separated Occupancies
178
Separated Occupancies
 Example:
Given: A fully sprinklered, four-story, Type IIA hotel,
containing a Group A-2 restaurant, Group A-3
meeting rooms and Group M retail stores. The floor
areas of each occupancy are as shown in the
following slide. Inadequate frontage provides for no
area increase.
Determine: If the building complies with the
allowable height and area provisions of Chapter 5.
Workbook page 75
Workbook page75
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Separated Occupancies
Overview of the Mixed-occupancy
Methods Section 508.3
Accessory Occupancies
Section 508.1
Nonseparated
Occupancies
Section 508.3
Separated Occupancies
Section 508.4
Individually classified
Individually classified
Individually classified
Allowable Area
For accessory occupancy, based on
allowable area of main occupancy
For building, based on
most restrictive of
occupancies under
consideration
For building, determined such that
the sum of the ratios of actual
area divided by
allowable area cannot exceed 1.0
Allowable Height
For accessory occupancy, based on
tabular values of Table 503
For building, based on
most restrictive of
occupancies under
consideration
For building, based on general
provisions of Section 503.1
Separation
No separation required between
occupancies
No separation
required between
occupancies
Fire-resistive separation as
required by Table 508.4
Most restrictive provisions
of Ch. 9 apply to entire
building
Not applicable to Groups
H-2, H-3, H-4 and H-5
Allowable area of building
determined by sum of ratios per
Section 506.5
Occupancy
Classification
1st
story
2nd story
3rd story
4th story
24,000/46,500 + 8,000/72,000 + 14,000/64,500 = 0.85 OK
46,000/72,000 = 0.64 OK
46,000/72,000 = 0.64 OK
8,000/46,500 + 38,000/72,000 = 0.70 OK
Aggregate for building
0.85 + 0.64 + 0.64 + 0.70 = 2.83 < 3 OK
Special
Conditions
Note: Each floor is analyzed for compliance on a floor-by-floor basis, plus the
building as a whole must also comply.
Workbook page 76
181
1.
2.
3.
4.
Subsidiary to main occupancy
Aggregate area < 10% of story
Aggregate area < value in Table 503
Most restrictive provisions of Ch. 9
apply to entire
5. building
6. Not applicable to Groups H-2, H-3, H4 and H-5
Workbook page 77
182
Practice Exercise 2
Practice exercises 2-6
 Given: A 9,250-square-foot (859 m2) single-story
building containing manufacturing (Group F-1) and
storage (Group S-1) uses as shown. The building is not
sprinklered, has open frontage allowing for a 25-percent
allowable area increase and is of Type VB construction.
 Determine: If a fire-resistance-rated separation is
required between the Group F-1 and S-1 occupancies.
 Located in the workbook, pages 79-83.
Workbook page 79-83
Workbook page 78
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2009 IBC Mixed Occupancies
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2009 IBC Mixed Occupancies
Practice Exercise 2
Practice Exercise 2 Solution
Accessory
Occupancies
Not applicable as 10-percent limitation is
exceeded.
Nonseparated
Occupancies
No separation is required.
Fire Protection
The provisions of Chapter 9 do not require a sprinkler
system or a fire alarm system for either occupancy.
Allowable Height
One-story limitation is met.
Allowable Area
The Group F-1 occupancy has the most restrictive
allowance of 10,625 square feet (987 m2) [8,500 +
2125], which exceeds actual area of 9,250 square
feet (859 m2).
Separated
Occupancies
No separation is required.
Table 508.3.3
No separation required between these two
occupancies.
Allowable Area
Sum of ratios does not exceed 1.0 (6,000/10,625 +
3,250/1x1,250 = 0.56 + 0.29 = 0.85).
Answer:
Workbook page 78
Workbook page 85
No Separation is required if either the nonseparated occupancies or
separated occupancies method is utilized.
185
Practice Exercise 3
186
Practice Exercise 3
 Given: A two-story district fire station contains
Group B, R-2 and S-1 occupancies as shown. The
building is fully sprinklered, constructed of Type VB
construction and has open frontage allowing for a 75percent allowable area increase.
 Determine: If the building can be constructed under the
nonseparated occupancies provisions for mixedoccupancy buildings.
Workbook page 79
Workbook page 79
187
2009 IBC Mixed Occupancies
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47
2009 IBC Mixed Occupancies
Practice Exercise 3 Solution
Accessory
Occupancies
Not applicable as 10-percent limitation is
exceeded.
Nonseparated
Occupancies
This method may be used as the actual area does not
exceed the allowable area.
Fire Protection
The provisions of Chapter 9 require a sprinkler system,
but not a fire alarm system.
Allowable Height
Two-story limitation based on Group S-1 is met.
Allowable Area
The Group R-2 has the most restrictive allowance of
26,250 square feet (2439 m2) [7,000 + 14,000 + 5,250].
The actual area of 8,400 square feet (780 m2), based
on the first story, is below the allowable area.
Separated
Occupancies
This method requires a minimum 1-hour fireresistive
separation between the Group R-2 occupancy and the
remainder of the building.
Answer:
Practice Exercise 4
 Given: A one-story multiple-tenant retail center
containing Group A-2, B and M occupancies as shown.
The 52,000-square-foot (4831 m2) building is fully
sprinklered, of Type IIB construction and has adequate
frontage for a 60- percent allowable area increase.
 Determine: If the building will comply with Section 508
for mixed occupancies. Is a fire separation required? If
so, what minimum rating is required?
Workbook page 86
Workbook page 80
189
Practice Exercise 4
190
Practice Exercise 4 Solution
Accessory
Occupancies
Not applicable as 10-percent limitation is exceeded.
Nonseparated
Occupancies
This method cannot be used as the actual area
exceeds the allowable area.
Answer:
Fire Protection
Workbook page 80
Workbook page 86
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2009 IBC Mixed Occupancies
The provisions of Chapter 9 require a sprinkler system
and a fire alarm system, which must be provided
throughout the building.
Allowable Height
Two-story limitation is met.
Allowable Area
The Group A-2 occupancy has the most restrictive
allowance of 43,700 square feet (4060 m2) [9,500 +
28,500 + 5,700]. The actual area of 52,000 square feet
(4831 m2) exceeds the allowable area.
Separated
Occupancies
A minimum 1-hour fire barrier is required between the
Group A-2 and M occupancies. No other fire
separations are required.
Table 508.3.3
No separation is required between the Group B and M
occupancies, the pair of Group A-2 occupancies and
the pair of Group M occupancies, but a minimum 1hour separation is mandated between the Group A-2
and M occupancies.
Allowable Area
Sum of ratios does not exceed 1.0 (12,000/43,700 +
30,000/57,200 + 10,000/105,800 = 0.27 + 0.52 + 0.09 =
0.88).
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2009 IBC Mixed Occupancies
Practice Exercise 4 Solution
Practice Exercise 5
 Given: A 74,400-square-foot (6912 m2),
fully sprinklered one-story building of Type VB
construction regulated under the unlimited area
provisions of Section 507.3. Adequate open space
surrounds the building. The building is primarily Group
F-1 manufacturing and contains a 4,600-square-foot
(427 m2) employee lunchroom with an occupant load of
307.
 Determine: If the building is in compliance when
applying the accessory occupancies provisions of
Section 508.2.
Answer:
 What if the nonseparated occupancies method is
applied to the Group A-2/M condition and separated
occupancies is used for the Group B/M relationship,
allowing for no fire separations?
 Allowable Area: Sum of ratios based on most restrictive of
A-2/M (42,000/ 43,700) + B (10,000/105,800) = 0.96 + 0.09
= 1.05.
 Sum of ratios exceeds 1.0, so this approach will not work.
Workbook page 86
Workbook page 81
193
Practice Exercise 5
Practice Exercise 5 Solution
Workbook page 81
Workbook page 87
195
2009 IBC Mixed Occupancies
194
 Accessory Occupancies: Classify lunchroom as
Group A-2 occupancy.
 Lunchroom is subsidiary to manufacturing activity. Lunchroom
does not exceed 10 percent of floor area of story. 10 percent
of 74,400 = 7,440 square feet (691 m2) maximum. Lunchroom
does not exceed tabular area of Table 503. 6,000 square feet
(557 m2) for Group A-2, Type VB construction.
 The building is sprinklered throughout. The manual fire alarm
system required in the Group A-2 occupancy is required
throughout the building.
 For allowable area purposes (includes unlimited area
provisions of Section 507), the lunchroom is considered part of
the Group F-1 occupancy.
 The lunchroom is not located higher than the first story.
 The building complies with the accessory occupancies
method.
196
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2009 IBC Mixed Occupancies
Practice Exercise 6
Practice Exercise 6
 Given: A fully sprinklered five-story hotel of
Type IIA construction contains the following occupancies
located as shown:
 The floor areas of each occupancy are as indicated.
Other than a 1-hour fireresistant separation of the hotel
guest room portion, no fire-resistant separations are
provided between occupancies on the first floor. Streets
on two sides provide for a 25-percent frontage increase
for allowable area.
 Determine: If the building complies with the provisions
of Section 508.1 regulating mixed-occupancy buildings.
 First story: Lobby (Group A-3), Restaurant (Group A-2),
Administrative Offices (Group B), Retail Sales Tenants
(Group M) and Hotel Guest Rooms (Group R-1)
 Second story: Meeting/Conference Rooms (Group A-3)
and Hotel Guest Rooms (Group R-1)
 Third and fifth stories: Hotel Guest Rooms (Group R-1)
 Fourth story: Restaurant (Group A-3) and Hotel Guest
Rooms (Group R-1)
Workbook page 82
Workbook page 82
197
Practice Exercise 6
198
Practice Exercise 6 Solution
Accessory
Occupancies
No benefit provided in those cases where
applicable.
Nonseparated
Occupancies
This method may not be used for the entire
building as Group A-2 limits building height to four
stories. It may be utilized on the first story without
applying to other stories.
Fire Protection
The building is fully sprinklered and has a fire alarm
system in accordance with Section 907.2.8.
Allowable Height
Four-story limitation based on Group A-2 is not met for
building.
Allowable Area
Groups A-2 and A-3 have the most restrictive allowance
of 50,375 square feet (4680 m2) [15,500 + 31,000 +
3,875] (1440 + 2880 + 360 m2). Since the aggregate
building area of all stories is 200,000 square feet (18
580 m2) [40,000 times five stories (3716 m2 times five
stories)] exceeds the allowable building area of 151,125
square feet (14 040 m2) [three times 50,375 (4680
m2)], the building is not in compliance for
allowable area.
Answer:
Workbook page 83
Workbook page 88
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2009 IBC Mixed Occupancies
200
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2009 IBC Mixed Occupancies
Practice Exercise 6 Solution
Separated
Occupancies
This method is used throughout the remainder of the
building. It requires a minimum 1-hour fireresistant
separation between the Group R-1 occupancy and all
other occupancy groups. The required 1-hour
separation is already provided horizontally due to the 1hour floor construction required in a Type IIA building.
Table 508.3.3
Group R-1 occupancies are not permitted above the
fifth story. Group A-2 and A-3 occupancies shall not be
located above the fourth story.
Allowable Area
For allowable area purposes based on individual
stories, the various occupancies on the first story will be
evaluated under the nonseparated occupancies
provisions of Section 508.3. Stories two through five will
be evaluated as separated occupancies in accordance
with Section 508.4. The allowable area for the building
as a whole will also be based upon the separated
occupancy provisions of Section 508.4.
Answer:
Practice Exercise 6 Solution







Allowable Area per Occupancy
A-2
50,375 square feet (4680 m2)
A-3
50,375 square feet (4680 m2)
B
121,875 square feet (11 322 m2)
M
69,875 square feet (6491 m2)
R-1
78,000 square feet (7246 m2)
1st story* 20,000/50,375 + 20,000/78,000 = 0.66 OK
(1858/4680 + 1858/7246 = 0.397 + 0.256 =
0.653 OK)
 2nd story 24,000/50,375 + 16,000/78,000 = 0.69 OK
(2230/4680 + 1486/7246 = 0.476 + 0.205 =
0.681 OK)
Workbook page 88
Workbook page 89
201
Practice Exercise 6 Solution
202
Practice Exercise 6 Solution
 Allowable Area per Occupancy
 3rd story 40,000/78,000 = 0.51 OK
(3716/7246 = 0.512 OK)
 4th story 6,000/50,375 + 34,000/78,000 = 0.56 OK
(557/4680 + 3159/7246 = 0.12 + 0.435 =
0.55 OK)
 5th story 40,000/78,000 = 0.51 OK (3716/7246 =
0.512 OK)
 All stories 0.66 + 0.69 + 0.51 + 0.56 + 0.51 = 2.93 < 3
OK (0.653 + 0.681 + 0.512 + 0.55 + 0.412 =
2.908 ? 3 OK)
Workbook page 89
Workbook page 89
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2009 IBC Mixed Occupancies
 *All portions of first story other than Group R-1
regulated as nonseparated occupancies, limited by
allowable areas of Group A-2/A-3 occupancies. As a
whole including the Group R-2 portion, first story then
regulated as separated occupancies.
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Final Reflection Activity
International Code Council is a Registered Provider with The American
Institute of Architects Continuing Education Systems. Credit earned on
completion of this program will be reported to CES Records for AIA
members. Certificates of Completion for non-AIA members are
available on request.
This program is registered with the AIA/CES for continuing professional
education. As such, it does not include content that may be deemed or
construed to be an approval or endorsement by the AIA of any material
of construction or any method or manner of handling, using, distributing,
or dealing in any material or product. Questions related to specific
materials, methods, and services will be addressed at the conclusion of
this presentation.
Workbook page 78
206
205
206
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2009 IBC Mixed Occupancies
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