Step by Step to determine a building’s Occupancy Classification (with examples of each)


When starting any design of new building construction or even a renovation one of the first steps is to determine the building’s Occupancy Classification.  This is very important because each classification has specific Dos, Don’ts, and regulations specific to the classification and groups.  The code uses Occupancy Classifications, which represent varying levels of hazard and risk to building occupants and adjacent properties, to classify buildings by their primary use and purpose.  In this post, we will assume your local jurisdiction has adopted the International Building Code (IBC) as it is the most popular model code in the USA and adopted in many countries worldwide.  The IBC organizes and categorizes buildings into 10 main Occupancy Classifications and when you consider subgroups there is a total of 26 groups.

For many buildings, it can be quite easy and straightforward to determine the building’s Occupancy Classification.  You simply go to the IBC Chapter 3 and find the building group listing that most closely matches your building’s usage.  For example if you are planning to design and build an office building then you would find that Section 304 “Business Group B” includes buildings uses for office, professional, or service-type transactions.  Similarly if you are planning a hotel you would find under section 310, “Residential Group R” specifically list Hotels and Motels as Residential Group R-1. 

ICC provides FREE access to all of their model codes. See our post for free links to all of the ICC codes such as IBC, IRC, IEBC, etc.

Why does the IBC have Occupancy Classifications?

The International Building Code (IBC) uses the occupancy group classifications to ensure buildings are designed and built to appropriate safety standards.  The occupancy classifications are grouped primarily based on their relative fire hazard and life safety properties such as how many people will be in the area, are there hazardous materials or manufacturing, and are people sleeping, cooking, living etc.  The rest of the codebook uses the occupancy classification to organize requirements like allowable building height, appropriate types of construction as well as occupant safety requirements such as means of egress, fire protection systems, fire rated wall separations and devices.

All Occupancy Groups and Examples

The information provided below is for general use only, additional information is available in the International Building Code specifically Chapter 3 Use and Occupancy Classifications.  You should also consult your Local Building Official or a Design Professional in determining the appropriate Classification for your situation.

Occupancy ClassificationExamples
Assembly Group A-1Movie Theaters, Concert Halls
Assembly Group A-2Restaurants, Bars, Cafeterias
Assembly Group A-3Churches, Gymnasiums, Libraries
Assembly Group A-4Arenas, Indoor Swimming Pools
Assembly Group A-5Outdoor Stadiums
Business Group BOffices, Colleges, Banks
Educational Group EK-12 Schools, Daycare Facilities
Factory and Industrial Group F-1Moderate-hazard Factories
Factory and Industrial Group F-2Low-hazard Factories
High Hazard Group H-1High-hazard Detonation
High Hazard Group H-2High-hazard Accelerated Burning
High Hazard Group H-3High-hazard Combustion
High Hazard Group H-4High-hazard Health
High Hazard Group H-5High-hazard Semiconductors
Institutional Group I-1Assisted living, Halfway Houses
(Greater than 16 occupancts)
Institutional Group I-2Hospitals, Nursing Homes
Institutional Group I-3Prisons, Detention Centers
Institutional Group I-4Adult or Child care facilities
Mercantile Group MDepartment or Drug Store, Markets
Residential Group R-1Hotels, Boarding Houses
Residential Group R-2Apartments, Dormitories, Live/ Work Units
Residential Group R-3Single family homes, Duplex homes
Residential Group R-4Assisted living, Halfway Houses
(Between 5 and 16 occupants)
Storage Group S-1Storage of Books, Furniture, Lumber
Storage Group S-2Storage of Glass, Metals, Food
Utility and Miscellaneous Group UBarns, Carports, Sheds

Below is much greater detail of each occupancy classification and more examples from the IBC.

Assembly Group A (IBC Chapter 3, Section 303)

Assembly Group A occupancy includes, among others, the use of a building or structure, or a portion thereof, for the gathering of persons for purposes such as civic, social or religious functions; recreation, food or drink consumption or awaiting transportation.  The codebook further breaks down Group A into smaller subgroups, A-1 through A-5. 

Exceptions:

  • An assembly building or space with an occupant load of less than 50 persons or less than 750 square feet (70 square meters) shall be classified as a Group B occupancy.
  • A room or space used for assembly purposes that is associated with a Group E occupancy is not considered a separate occupancy.
  • Accessory religious educational rooms and religious auditoriums with occupant loads of less than 100 per room or space are not considered separate occupancies.

Assembly Group A-1

Group A-1 occupancy includes assembly uses, usually with fixed seating, intended for the production and viewing of the performing arts or motion pictures.

Examples of IBC Assembly Group A-1 Occupancies include, but not limited to:

  • Motion picture theaters
  • Symphony and concert halls
  • Television and radio studios admitting an audience
  • Theaters

Assembly Group A-2

Group A-2 occupancy includes assembly uses intended for food and/or drink consumption.

Examples of IBC Assembly Group A-2 Occupancies include, but not limited to:

  • Banquet halls
  • Casinos (gaming areas)
  • Nightclubs
  • Restaurants, cafeterias and similar dining facilities
    • (including associated commercial kitchens)
  • Taverns and bars

Assembly Group A-3

Group A-3 occupancy includes assembly uses intended for worship, recreation or amusement and other assembly uses not classified elsewhere in Group A.

Examples of IBC Assembly Group A-3 Occupancies include, but not limited to:

  • Amusement arcades
  • Art galleries
  • Bowling alleys
  • Community halls
  • Courtrooms
  • Dance halls (not including food or drink consumption)
  • Exhibition halls
  • Funeral parlors
  • Greenhouses for the conservation and exhibition of plants that provide public access.
  • Gymnasiums (without spectator seating)
  • Indoor swimming pools (without spectator seating)
  • Indoor tennis courts (without spectator seating)
  • Lecture halls
  • Libraries
  • Museums
  • Places of religious worship
  • Pool and billiard parlors
  • Waiting areas in transportation terminals

Assembly Group A-4

Group A-4 occupancy includes assembly uses intended for viewing of indoor sporting events and activities with spectator seating.

Examples of IBC Assembly Group A-4 Occupancies include, but not limited to:

  • Arenas
  • Skating rinks
  • Swimming pools
  • Tennis courts

Assembly Group A-5

Group A-5 occupancy includes assembly uses intended for participation in or viewing out-door activities.

Examples of IBC Assembly Group A-5 Occupancies include, but not limited to:

  • Amusement park structures
  • Bleachers
  • Grandstands
  • Stadiums

Business Group B (IBC Chapter 3, Section 304)

Business Group B occupancy includes, among others, the use of a building or structure, or a portion thereof, for office, professional or service-type transactions, including storage of records and accounts.

Examples of IBC Business Group B Occupancies include, but not limited to:

  • Airport traffic control towers
  • Ambulatory care facilities
  • Animal hospitals, kennels and pounds
  • Banks
  • Barber and beauty shops
  • Car wash
  • Civic administration
  • Clinic, outpatient
  • Dry cleaning and laundries: pick-up and delivery stations and self-service
  • Educational occupancies for students above the 12th grade
  • Electronic data processing
  • Food processing establishments and commercial kitchens not associated with restaurants, cafeterias and similar dining facilities not more than 2,500 square feet (232 square meters) in area.
  • Laboratories: testing and research
  • Motor vehicle showrooms
  • Post offices
  • Print shops
  • Professional services (architects, attorneys, dentists, physicians, engineers, etc.)
  • Radio and television stations
  • Telephone exchanges
  • Training and skill development not in a school or academic program (this shall include, but not be limited to, tutoring centers, martial arts studios, gymnastics and similar uses regardless of the ages served, and where not classified as a Group A occupancy)

Education Group E (IBC Chapter 3, Section 305)

Educational Group E occupancy includes, among others, the use of a building or structure, or a portion thereof, by six or more persons at any one time for educational purposes through the 12th grade. 

Examples of IBC Education Group E Occupancies include, but not limited to:

  • Public and private K-12 schools
  • Religious educational rooms (accessory to places of worship with 100 or more occupants)
  • Religious auditoriums (accessory to places of worship with 100 or more occupants)
  • Day care facilities (more than 5 children older than 2 ½ years of age)

Factory Group F (IBC Chapter 3, Section 306)

Factory Industrial Group F occupancy includes, among others, the use of a building or structure, or a portion thereof, for assembling, disassembling, fabricating, finishing, manufacturing, packaging, repair or processing operations that are not classified as a Group H hazardous or Group S storage occupancy. The codebook further breaks down Group F into two smaller subgroups, F-1 and F-2.

Factory Group F-1 – Moderate-Hazard Factory Industrial

Group F-1 occupancy includes all buildings that are not classified as F-2, low-hazard factory industrial.

Examples of IBC Factory Group F-1 Occupancies include, but not limited to:

  • Aircraft (manufacturing, not to include repair)
  • Appliances
  • Athletic equipment
  • Automobiles and other motor vehicles
  • Bakeries
  • Beverages: over 16-percent alcohol content
  • Bicycles
  • Boats
  • Brooms or brushes
  • Business machines
  • Cameras and photo equipment
  • Canvas or similar fabric
  • Carpets and rugs (includes cleaning)
  • Clothing
  • Construction and agricultural machinery
  • Disinfectants
  • Dry cleaning and dyeing
  • Electric generation plants
  • Electronics
  • Engines (including rebuilding)
  • Food processing establishments and commercial kitchens not associated with restaurants, cafeterias and similar dining facilities more than 2,500 square feet (232 square meters) in area.
  • Furniture
  • Hemp products
  • Jute products
  • Laundries
  • Leather products
  • Machinery
  • Metals
  • Millwork (sash and door)
  • Motion pictures and television filming (without spectators)
  • Musical instruments
  • Optical goods
  • Paper mills or products
  • Photographic film
  • Plastic products
  • Printing or publishing
  • Recreational vehicles
  • Refuse incineration
  • Shoes
  • Soaps and detergents
  • Textiles
  • Tobacco
  • Trailers
  • Upholstering
  • Wood; distillation
  • Woodworking (cabinet)

Factory Group F-2 – Low-Hazard Factory Industrial

Group F-2 occupancy includes factory industrial uses that involve the fabrication or manufacturing of noncombustible materials that during finishing, packing or processing do not involve a significant fire hazard

Examples of IBC Factory Group F-2 Occupancies include, but not limited to:

  • Beverages: up to and including 16-percent alcohol content
  • Brick and masonry
  • Ceramic products
  • Foundries
  • Glass products
  • Gypsum
  • Ice
  • Metal products (fabrication and assembly)

High-Hazard Group H (IBC Chapter 3, Section 307)

High-hazard Group H occupancy includes, among others, the use of a building or structure, or a portion thereof, that involves the manufacturing, processing, generation or storage of materials that constitute a physical or health hazard in quantities in excess of those allowed in control areas. The codebook further breaks down Group F into five smaller subgroups, H-1 through H-5. Group H can be a very complicated group to navigate and it is recommended to contact your local Building Official for assistance. 

Exceptions:

  • Hazardous materials stored, or used on top of roofs or canopies, shall be classified as outdoor storage or use and shall comply with the International Fire Code.
  • An occupancy that stores, uses or handles hazardous materials as described in Section 307.1 shall not be classified as Group H, but shall be classified as the occupancy that it most nearly resembles.  See Table 307.1 for Maximum Allowable Quantities for the hazardous material.  The table gives guidance on what H group you fall into if the maximum allowable quantity is exceeded.

Group H-1 – High-Hazard Detonation

Group H-1 occupancy includes buildings and structures containing materials that pose a detonation hazard.

Group H-2 – High-Hazard Deflagration or Accelerated Burning

Group H-2 occupancy includes buildings and structures containing materials that pose a deflagration hazard or a hazard from accelerated .

Group H-3 – High-Hazard Combustion or Physical

Group H-3 occupancy includes buildings and structures containing materials that readily support combustion or that pose a physical hazard.

Group H-4 – High-Hazard Health

Group H-4 occupancy includes buildings and structures which contain materials that are health hazards.

Group H-5 – High-Hazard Semiconductor, Research and Development

Group H-5 occupancy includes semiconductor fabrication facilities and comparable research and development areas in which hazardous production materials are used and the aggregate quantity of materials is greater than the allowable quantities in table 307.1.

Institutional Group I (IBC Chapter 3, Section 308)

Institutional Group I occupancy includes, among others, the use of a building or structure, or a portion thereof, in which people are cared for or live in a supervised environment, having physical limitations because of health or age are harbored for medical treatment or other care or treatment, or in which people are detained for penal or correctional purposes or in which the liberty of the occupants is restricted. The codebook further breaks down Group I into smaller subgroups, I-1 through I-4. 

Group I-1 – Institutional Personal Care Services

Group I-1 occupancy includes buildings, structures or portions thereof for more than 16 persons who reside on a 24-hour basis in a supervised environment and receive custodial care. The persons receiving care are capable of self-preservation.

Examples of IBC Institutional Group I-1 Occupancies include, but not limited to:

  • Alcohol and drug centers
  • Assisted living facilities
  • Congregate care facilities
  • Convalescent facilities
  • Group homes
  • Halfway houses
  • Residential board and custodial care facilities
  • Social rehabilitation facilities

Group I-2 – Institutional medical, surgical, psychiatric, nursing or custodial care

Group I-2 occupancy includes buildings used for medical, surgical, psychiatric, nursing or custodial care for persons who are not capable of self-preservation

Examples of IBC Institutional Group I-2 Occupancies include, but not limited to:

  • Detoxification facilities
  • Foster care facilities
  • Hospitals
  • Nursing homes
  • Psychatric hospitals

Group I-3 – Institutional restraint or security

Group I-3 occupancy includes buildings and structures that are inhabited by more than five persons who are under restraint or security. An I-3 facility is occupied by persons who are generally incapable of self-preservation due to security measures not under the occupants’ control.

Examples of IBC Institutional Group I-3 Occupancies include, but not limited to:

  • Correctional centers
  • Detention centers
  • Jails
  • Pre-release centers
  • Prisons
  • Reformatories

Group I-4 – Institutional care facilities

Group I-4 occupancy includes buildings and structures occupied by persons of any age who receive custodial care for less than 24 hours by individuals other than parents or guardians, relatives by blood, marriage or adoption, and in a place other than the home of the person cared.

Examples of IBC Institutional Group I-4 Occupancies include, but not limited to:

  • Adult care facility
  • Child care facility

Education Group M (IBC Chapter 3, Section 309)

Mercantile Group M occupancy includes, among others, the use of a building or structure or a portion thereof, for the display and sale of merchandise and involves stocks of goods, wares or merchandise incidental to such purposes and accessible to the public.

Examples of IBC Mercantile Group M Occupancies include, but not limited to:

  • Department stores
  • Drug stores
  • Markets
  • Greenhouses for display and sale of plants that provide public access.
  • Motor fuel-dispensing facilities
  • Retail or wholesale stores
  • Sales rooms

Residential Group R (IBC Chapter 3, Section 310)

Institutional Group R includes, among others, the use of a building or structure, or a portion thereof, for sleeping purposes when not classified as an Institutional Group I. The codebook further breaks down Group R into smaller subgroups, R-1 through R-4. 

Residential Group R-1

Group R-1 occupancy containing sleeping units where the occupants are primarily transient in nature.

Examples of IBC Residential Group R-1 Occupancies include, but not limited to:

  • Apartment houses
  • Congregate living facilities (nontransient) with more than 16 occupants
  • Boarding houses (nontransient)
  • Convents
  • Dormitories
  • Fraternities and sororities
  • Monasteries
  • Hotels (nontransient)
  • Live/work units
  • Motels (nontransient)
  • Vacation timeshare properties

Residential Group R-2

Group R-2 occupancy containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature.

Examples of IBC Residential Group R-2 Occupancies include, but not limited to:

  • Apartment houses
  • Congregate living facilities (nontransient) with more than 16 occupants
  • Boarding houses (nontransient)
  • Convents
  • Dormitories
  • Fraternities and sororities
  • Monasteries
  • Hotels (nontransient)
  • Live/work units
  • Motels (nontransient)
  • Vacation timeshare properties

Residential Group R-3

Group R-3 occupancy is buildings where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I.

Examples of IBC Residential Group R-3 Occupancies include, but not limited to:

  • Adult or Child care facilities (five or fewer persons of any age for less than 24 hours)
  • Congregate living facilities (16 or fewer persons)
    • Boarding houses
    • Convents
    • Dormitories
    • Fraternities and sororities
    • Monasteries
  • Duplex dwelling units
  • Single family dwelling units

Residential Group R-4

Group R-4 occupancy includes buildings where the occupants are primarily permanent in nature and are arranged for, more than 5 but not more than 16 persons, excluding staff, who reside on a 24 hour basis in a supervised environment and receive custodial care. The persons receiving care are capable of self-preservation.

Examples of IBC Residential Group R-4 Occupancies include, but not limited to:

  • Alcohol and drug centers
  • Assisted living facilities
  • Congregate care facilities
  • Convalescent facilities
  • Group homes
  • Halfway houses
  • Residential board and custodial care facilities
  • Social rehabilitation facilities

Storage Group S (IBC Chapter 3, Section 311)

Institutional Group S includes buildings for storage that is not classified as a hazardous occupancy. The codebook further breaks down Group S into two smaller subgroups, S-1 and S-2. 

Storage Group S-1 – Moderate-hazard

Group S-1 occupancy containing buildings occupied for storage uses that are not classified in Group S-2.

Examples of IBC Storage Group S-1 Occupancies include, but not limited to:

  • Aerosols, Levels 2 and 3
  • Aircraft hangar
  • Bags: cloth, burlap and paper
  • Bamboos and rattan
  • Baskets
  • Belting: canvas and leather
  • Books and paper in rolls or packs
  • Boots and shoes
  • Buttons
  • Cardboard and cardboard boxes
  • Clothing
  • Cordage
  • Dry boat storage
  • Furniture
  • Furs
  • Glues, mucilage, pastes and size
  • Grains
  • Horns and combs
  • Leather
  • Linoleum
  • Lumber
  • Mattresses
  • Motor vehicle repair garages
  • Photo engravings
  • Resilient flooring
  • Silks
  • Soaps
  • Sugar
  • Tires
  • Tobacco, cigars, cigarettes and snuff
  • Upholstery
  • Wax candles

Storage Group S-2 – Low-hazard

Group S-2 occupancy includes buildings used for the storage of noncombustible materials such as products on wood pallets or in paper cartons with or without single thickness divisions; or in paper wrappings. Such products are permitted to have a negligible amount of plastic trim, such as knobs, handles or film wrapping.

Examples of IBC Storage Group S-2 Occupancies include, but not limited to:

  • Asbestos
  • Beverages up to and including 16-percent alcohol in metal, glass or ceramic containers
  • Cement in bags
  • Chalk and crayons
  • Dairy products in nonwaxed coated paper containers
  • Dry cell batteries
  • Electrical coils
  • Electrical motors
  • Empty cans
  • Food products
  • Foods in noncombustible containers
  • Fresh fruits and vegetables in nonplastic trays or containers
  • Frozen foods
  • Glass
  • Glass bottles, empty or filled with noncombustible liquids
  • Gypsum board
  • Inert pigments
  • Ivory
  • Meats
  • Metal cabinets
  • Metal desks with plastic tops and trim
  • Metal parts
  • Metals
  • Mirrors
  • Oil-filled and other types of distribution transformers
  • Parking garages, open or enclosed
  • Porcelain and pottery
  • Stoves
  • Talc and soapstones
  • Washers and dryers

Utility and Miscellaneous Group U (IBC Chapter 3, Section 312)

Utility Group U occupancy includes buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy.

Examples of IBC Utility Group U Occupancies include, but not limited to:

  • Agricultural buildings
  • Barns
  • Carports
  • Fences more than 6 feet high
  • Greenhouses (not classified as another occupancy)
  • Livestock shelters
  • Private garages
  • Residential aircraft hangars
  • Residential grain silos
  • Retaining walls
  • Sheds
  • Stables
  • Tanks
  • Towers

Related Questions

What if my building does not match an exact Occupany Group Classification?

When a building’s usage purpose does not fit neatly into one of the prescribed groups the IBC tells us that the structure shall be classified “in the occupancy it most nearly resembles based on fire safety and relative hazard.”  Although it is typically the Architect’s responsibility to determine the Occupancy Classification, it should be remembered that the ultimately the Building Official will make the final call.  However if the code official makes a determination that you do not agree with there are means for appealing the decision. 

What if my building has mixed use?

Buildings, such as a mall (with restaurants, shops, and maybe even a hotel) that have more than one occupancy group intended are called mixed occupancy buildings.  Section 508 of the IBC has guidelines on Mixed Use Buildings and establishes guidelines for allowable height, area of the building, and separation.

Can you change a building’s Occupancy Classification?

Yes, you can change a building’s Occupancy Classification and you should do so if the buildings use is changing.  Your architect or engineer will need to submit to the city, county or other jurisdiction and request the change.  Typically this includes the design professional creating new stamped and sealed drawings and will typically require a permit from the building department.  The drawings should at a minimum, include a building code analysis sheet, site plan, floor plans of each level, stair details, and cross sections to illustrate wall types, insulation, ceiling heights and the relationship to the outside grade and interior floor elevations.

You should keep a few things in mind when changing an occupancy.  The change may trigger some code-required upgrades such as accessibility improvements, seismic upgrades, and some life safety improvements such as fire sprinklers and/ or rated wall partitions.  In addition, you find that the code requires more parking for your new occupancy and you simply may not have the space required to add the additional parking. 

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