Occupancy classifications indicate the approved usage of built spaces. The features of indoor environments and the activities performed have a big impact on the characteristics of a fire that might occur, and thus they also determine which fire alarm system design is appropriate.

Buildings, or portions thereof, should be classified under the occupancy group they resemble the most, considering the fire safety and relative hazard involved. In addition, approval by the FDNY commissioner is required.

Occupancy Groups Where Fire Alarms Are Required

Since fire alarms play a key role in alerting occupants when a fire occurs, they are required in a wide range of built environments. The following table summarizes the requirements for each occupancy group:

OCCUPANCY GROUP

CONDITIONS FOR MANDATORY FIRE ALARMS

Assembly Group A

Occupant load of at least 300

Business Group B



Locations protected by an automatic sprinkler system, plus at least one of the following conditions:
1. At least 500 occupants across all floors
2. More than 100 occupants above or below the lowest exit discharge level
3. A fire area containing an ambulatory healthcare facility

Educational 
Group E

All Group E occupancies.

Factory and Industrial Group F

Occupancies at least two stories high, plus at least one of the following conditions:
1. Total occupant load of at least 100
2. At least 25 occupants above or below the lowest exit discharge level

High Hazard
Group H

Subgroup H-5, and all occupancies used for the manufacture of organic coatings.

Institutional
Group I

All Group I occupancies.

Mercantile
Group M



Occupancies that meet at least one of the following conditions:
1. A single fire area exceeding 12,000 sq.ft.
2. A fire area located more than three stories above grade.
3. Combined fire area across all floors exceeding 24,000 sq.ft.
4. A fire area below grade exceeding 1,500 sq.ft.

Residential
Group R






All subgroup R-1 occupancies, unless they meet a series of fire protection measures and exit accessibility requirements detailed in Article 907.2.8

Subgroup R-2 occupancies that meet either of the following conditions:
1. Any dwelling units are located at least three stores above the lowest exit discharge level.
2. Any dwelling units are located more than one story below the highest exit discharge level.
3. Buildings with at least 16 dwelling units.
4. Student apartments.

The NYC Building Code also establishes special fire alarm requirements for buildings that meet either of the following descriptions, regardless of occupancy classification:

  • High-rise buildings
  • Atriums that connect more than two stories
  • Aerosol storage rooms and warehouses
  • Lumber mills and other wood processing applications
  • Underground buildings
  • Covered mall buildings above 50,000 sq. ft.

This list is a general guide, and should not be considered a replacement for the NYC Building Code. Detailed requirements and exceptions apply in many cases, and they should be taken into account before designing and installing a fire alarm system. Consider that fire alarms systems must also meet the NFPA 72 standard, in addition to the NYC Building Code.

Fire Alarm System: Device Requirements by Occupancy

Just like the general requirement to install fire alarms changes by occupancy, the device requirements also vary. They are summarized in the following table:

Occupancy

Areas Covered

Devices Required

Assembly
Group A




Any number of occupants: civic or social functions, worship, recreation, food or beverage consumption, transportation waiting areas, or similar group activities.

75 persons or more: educational or instructional purposes.

- Manual pull station
- Voice/alarm communication system
- CO detectors
- Control relay modules
- Monitor modules

Business
Group B


Office spaces, professional and service-type transactions, public or civic services, limited record and account storage, and limited stocked goods for office usage.

- Manual pull station
- Smoke/heat detectors
- Control relay modules
- Monitor modules

Educational
Group E


Buildings intended for usage by at least five persons simultaneously, for educational purposes up to 12th grade, and where no more than two children are under age 2.

- Manual pull station
- Smoke detectors
- Control relay modules
- Monitor modules.

Factory and Industrial
Group F

Industrial activity with non-combustible materials, including cleaning, laundering, fabrication, manufacturing, finishing, packing or processing, among others.

- Manual pull station
- CO detectors
- Control relay modules
- Monitor modules

High Hazard
Group H


Manufacturing, processing, generation or storage activities, with dangerous materials that represent a physical or health hazard in the quantities present.

- Manual pull station
- CO detectors
- Control relay modules
- Monitor modules

Institutional
Group I




Supervised environments for people with physical limitations due to health or advanced age, for care-taking or treatment. Also includes facilities where people are detained for penal or correctional purposes.



- Manual pull station
- Voice/alarm communication system
- CO detectors
- Control relay modules
- Monitor modules
- Notification devices

Mercantile
Group M


Spaces uses to display and sell merchandise, which may include storage areas.


- Notification devices
- Control relay modules
- Monitor modules
- Manual Pull station

Residential
Group R



Buildings, or building portions, used for living or sleeping, but not including occupancies classified as Group I.



- Smoke detectors
- Control relay modules
- Monitor modules
- Two-way communication system (only for high-rise buildings)

Storage
Group S*

Warehouses, storage rooms, freight depots and distribution centers that are not classified under Group H.

- Manual pull station
- Notification devices

Utility and Miscellaneous
Group U*

Accessory areas such as private garages, retaining walls, sheds and carports.

- Manual pull station
- Notification devices

*The NYC Building Code does not make fire alarms mandatory in these occupancy groups, except in special cases, but there are still requirements to meet if the decision to install a fire alarm is made.

Final Recommendations

This article deals exclusively with requirements for fire alarm systems, but consider there are only among many fire protection systems for buildings. In addition, these other systems may or may not be mandatory depending the occupancy classification, and there are also requirements that vary by occupancy.

NYC has very stringent fire protection standards, so the best recommendation is to seek professional engineering services from the start of the project. In the specific case of high-rise office buildings, it is very important to ensure the property is fully sprinklered according to Local Law 26 of 2004, where the deadline is July 1, 2019.

Code References

  • NFPA 72.
  • NYC building code chapter 3.
  • NYC building code chapter 9 section BC 907

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