For a building owner, navigating the maze of fire safety regulations is difficult at best and, at times, downright confusing. A big part of that confusion is the fact that while most states’ fire regulations are based on the National Fire Protection Association (NFPA) standards, there are also fire safety requirements outlined in building codes. Most of these codes are based on the International Building Code (IBC). And, they don’t always match up well with the NFPA codes.
In this post, we will provide some clarity, specifically around occupancy classifications. Occupancy classifications are one of the most critical elements of fire code for building owners to understand because they provide the basis for almost all of the other fire protection regulations they will be required to meet, including sprinkler systems.
We have written about the different occupancy classifications in the NFPA codes pertaining to sprinkler systems here. This post will focus specifically on the occupancy classifications in the IBC and the sprinkler system requirements they contain. While the requirements in both the NFPA and IBC are intended to improve fire safety, it is very easy to confuse the occupancy classifications they contain and their associated requirements.
Comparing the Occupancy Classifications in the IBC and NFPA
In the IBC, occupancy classifications refer to how the structure or portion of a structure is used, specifically the purpose for which it will be used, the size of the space, and the number of people that could be using it at any given time. This is referred to as the “occupant load,” which is the number of persons for which the means of egress from a building or part of a building is designed. These factors are used to determine the relative fire hazards in a given space and inform the fire safety requirements in the IBC, including those for sprinkler systems.
There are ten basic types of occupancies in Section 3 of the IBC, each of which has subclassifications called “Groups” based on various factors that might affect the level of risk associated with a fire. These occupancy classifications provide the basis for the sprinkler system requirements in Section 9 of the IBC, which makes finding the applicable requirements relatively straightforward.
Where the confusion comes in is when you start with the IBC and then want to find the associated requirements in the NFPA codes. At first glance, this might seem pretty straightforward, too, because the occupancy classifications in the IBC are quite similar to the occupancy classifications in NFPA 101 Life Safety Code (Table 1). However, to understand the requirements for sprinkler systems, these are not the relevant occupancy classifications. The NFPA requirements for sprinkler systems are based on an entirely different set of occupancies, which are defined in Chapter 5 of the NFPA 13 Standard for the Installation of Sprinkler Systems:
Chapter 5 Classification of Occupancies and Commodities
5.1 Classification of Occupancies
5.1.1 Occupancy classifications for this standard shall relate to sprinkler design, installation, and water supply requirements only.
Table 1: A comparison illustrating the similarities between the occupancy classifications in NFPA 101 and those in the IBC.
| Occupancy Category | NFPA 101 Occupancy Classification | IBC Occupancy Group | Examples |
| Assembly | Assembly |
A-1 |
Fixed seating, production/viewing |
| A-2 | Restaurants, nightclubs | ||
| A-3 | Other assemblies (gyms, museums) | ||
| A-4 | Arenas, pools | ||
| A-5 | Bleachers, grandstands | ||
| Business | Business | B | Offices, dentists' offices, city halls |
| Educational | Educational | E | Schools ≤ grade 12 |
| Industrial | Industrial |
F-1 |
Facilities with moderate hazards |
| F-2 | Factories with low hazards (bricks, glass) | ||
| Storage | Storage | S-1 | Storage with moderate hazards (furniture) |
| S-2 | Storage with low hazards (canned goods) | ||
| High Hazard | Occupancy Type + hazardous contents requirements | H-1 | Detonation hazard (explosives) |
| H-2 | Accelerated burning hazard (flammable gasses) | ||
| H-3 | Supported combustion hazard (flammable solids) | ||
| H-4 | Health hazards | ||
| H-5 | Semiconductor fabrications | ||
|
Medical Care /Institutional |
Healthcare (4+ patients) |
I-2 (>5 patients) |
Inpatient (24 hr) care, nursing homes |
|
Board & Care |
Residential Board & Care (4+ persons) |
I-1 (>16 persons) |
Personal care services & lodging |
|
Day-Care |
Day-Care (4+ clients) |
I-4 (>5 persons) |
Care & supervision (>24 hr) |
|
Detention & Correctional |
Detention & Correctional (1+ persons) |
I-3 (>5 persons) |
Occupants under restraint or security |
|
Mercantile |
Mercantile |
M |
Display, sale of goods (retail) |
| Residential |
Hotel & Dormitories |
R-1 |
Hotels, Motels (transient use) |
|
Hotel & Dormitories |
R-2 |
Dormitories |
|
|
Apartments |
Apartments |
||
|
Lodging and Rooming |
R-3 |
Boarding |
|
|
Board & Care |
R-4 (5-16 persons) |
Board & Care, rehab facilities |
|
|
Special Structures |
Occupancy Type + Special Structure provisions |
Group U |
Towers, tanks |
(Modified from NFPA Xchange, 2017)
In contrast to the occupancy classifications in the IBC, there are only five occupancy classifications in NFPA 13 (Table 2). These classifications are based on the fire hazards that might be expected in a building or space within as opposed to its intended use or occupancy load.
Table 2: Occupancy classifications in NFPA 13 based on fire hazard associated with the occupancy as opposed to its intended use or occupancy load.
| Hazard Type | NFPA 13 Occupancy Classification | Examples |
|
Light Hazards |
Light Hazard |
Offices, healthcare facilities, churches, schools |
|
Ordinary Hazards |
Ordinary Hazard (Group 1) |
Mechanical plants, laundries, food processing facilities, or other manufacturing operations in which a fire would release moderate rates of heat |
|
Ordinary Hazard (Group 2) |
Distilleries, barns and stables, dry cleaners, libraries, machine rooms, and auto repair shops |
|
| Extra Hazards |
Extra Hazard (Group 1) |
Spaces with some small amounts of combustible or flammable liquids, but the classification is primarily based on the presence of highly combustible solids |
| Extra Hazard (Group 2) |
Plastic manufacturing operations, steel manufacturing, and automobile paint spray booths |
In our previous post, Commodity and Occupancy Classifications for Fire Sprinklers, we provide a more thorough treatment of the NFPA 13 occupancy classifications shown in Table 2. Below, we provide a summary of the sprinkler requirements in the IBC based on the occupancy classifications defined in the IBC (Table 3).
Table 3: Summary of occupancy classifications in the IBC and their associated sprinkler system requirements.
| IBC Occupancy Groups | Summary of Sprinkler Requirements in the IBC |
|
Assemblies Groups A-1 through A-5 |
An automatic sprinkler system is required for the fire area in which the Group A occupancy exists and the intervening floors if any of the following conditions exist:
An automatic sprinkler system is required where multiple fire areas comprised of Group A-1, A-2, A-3, or A-4 occupancies share exits or access to exits, and the combined occupant load of these fire areas is 300 or more. An automatic sprinkler system is required in the following areas in a Group 5 occupancy:
|
|
Educational Occupancies Group E |
With some exceptions, an automatic sprinkler system is required throughout the fire areas greater than 12,000 square feet in all Group E occupancies and every space within the educational buildings that is below the lowest level of exit discharge serving that part of the building |
|
Industrial Occupancies Group F-1 |
An automatic sprinkler system is required throughout all buildings with a Group F-1 occupancy if any of the following conditions exist: ● The fire area exceeds 12,000 square feet (Group F-1) ● The fire area is located more than three stories above the lowest level of fire department vehicle access ● The combined area of all Group F-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet ● The occupancy used for the manufacture of upholstered furniture or mattresses exceeds 2,500 square feet (Group F-1)
An automatic sprinkler system is required throughout all Group F-1 occupancy fire areas that contain woodworking operations in areas greater than 2,500 square feet that generate finely divided combustible waste or use finely divided combustible materials |
|
Storage Occupancies Group S-1 and S-2 |
An automatic sprinkler system is required throughout all buildings with a Group S-1 occupancy when any one of the following conditions exist: ● The fire area exceeds 12,000 square feet (Group S-1) ● The fire area is located more than three stories above the lowest level of fire department vehicle access (Group S-1) ● The combined area of all Group S-1 fire areas on all floors, including any mezzanines, exceeds 24,000 square feet ● If the fire area is used for the storage of commercial motor vehicles exceeds 5,000 square feet ● If the fire area used for the storage of upholstered furniture or mattresses exceeds 2,500 square feet
An automatic sprinkler system is required for all enclosed parking garages except those located beneath Group R-3 occupancies when either of the following conditions exist: ● Where the enclosed parking garage is located beneath other occupancy groups (S-2) ● The fire area exceeds 12,000 square feet (Group S-2) |
|
High Hazard Occupancies Groups H-1 through H5 |
The IBC requires an automatic sprinkler system for all Group H occupancies and provides design criteria specifically for Group H-5, based on the occupancy hazard classification associated with the occupancy group |
|
Groups I-1 through I-4 Occupancies |
With few exceptions, an automatic sprinkler system is required throughout all buildings with a Group I occupancy |
|
Mercantile Occupancies Group M |
An automatic sprinkler system is required throughout buildings with a Group M occupancy where any one of the following conditions exists: ● The fire area exceeds 12,000 square feet ● The fire area is located more than three stories above the lowest level of fire department vehicle access ● The combined area of all Group M fire areas on all floors, including any mezzanines, exceeds 24,000 square feet ● The occupancy is used for the display and sale of upholstered furniture or mattresses and exceeds 5,000 square feet ● Storage of merchandise is in high-piled or rack storage arrays |
|
Residential Occupancies Groups R-1 through R4 |
With some exceptions, an automatic sprinkler system is required throughout all buildings with a Group R occupancy, including their attics if used for living purposes, storage, or fuel-fired equipment |
|
Special Structures Group U |
Group U occupancies include a wide variety of special structures that are defined as “miscellaneous structures” or those of an “accessory character,” making it difficult to summarize here. The IBC provides some examples of these types of occupancies and indicates that the requirements with regard to fire safety are based on the relative fire and life hazards “incidental to their occupancy.” |
Both the NFPA and IBC occupancy classifications have the same intended purpose – to protect people from fires. However, the IBC is conceptually very different from the NFPA. While the IBC addresses a broad range of concerns with regard to building safety, including fire safety, the NFPA 101 addresses concerns relating to the construction, protection, and occupancy features necessary to minimize the danger to life from the effects of fire. But, when it comes to sprinkler systems specifically, when they are required by the IBC, with few exceptions, they must be installed in accordance with NFPA 13.
In Summary
It is useful to know that the IBC requirements for sprinkler systems typically apply only to new buildings or structures. If you are considering replacing a sprinkler system in an existing building, the IBC requirements would likely not apply. However, they might if you are renovating. And, the NFPA 13 requirements would apply in almost every case.
The differences in how the NFPA and IBC define the term “occupancy” and the fact that a unique set of occupancy classifications exist in the NFPA codes specifically for sprinkler systems can lead to confusion when trying to determine the sprinkler system requirements that apply to your situation.
So, how do you figure out which requirements apply? That part is simple – call Koorsen. With more than 70 years in the fire safety industry and regulatory experts on hand, we can help you navigate the complex maze of fire safety regulations to ensure the system you choose is right for your application and will be in full compliance with all applicable codes. Contact Koorsen anytime with all your sprinkler system questions.
