NYC Fire Alarm System Requirements by Occupancy Group

Understanding fire alarm system requirements by occupancy group is critical for any project in New York City. The NYC Building Code (BC 907), together with BC 903 for sprinklers and the NYC Fire Code, establishes a framework that dictates when manual pull stations, automatic detection, voice/alarm systems, and monitoring are required based on a building’s use and size. Because each occupancy group (Assembly, Residential, Business, Mercantile, Storage, and others) has its own distinct triggers and exceptions, even minor design changes can shift the fire alarm requirements significantly. This article explains how those requirements are applied under BC 907, illustrates key thresholds that activate alarm and sprinkler systems, and highlights common design pitfalls encountered in NYC fire protection design and permitting.

What “triggers” a fire alarm system?

BC 907 lists conditions by occupancy group when manual (pull stations) and automatic (smoke/heat, waterflow) initiation, and sometimes emergency voice/alarm communication systems (EVACS), are required.

• Manual fire alarm boxes (pull stations): When a fire alarm system is required, at least one manual box must be provided (even when other boxes are permitted to be eliminated due to sprinklers). Placement rules include ≤ 5 ft from each exit.

• Automatic initiation: Fire alarm systems are typically activated through automatic detection devices, such as smoke, heat, or sprinkler waterflow detectors, when required by occupancy group or system design per BC §907.2. In many cases, these automatic devices work in conjunction with manual pull stations and central monitoring to provide full building protection.

• EVACS (voice/alarm): Required in specific uses (e.g., E, certain R-1, large S buildings); R-2 high-rise has special voice/communication rules unique to NYC.

• Monitoring: Required systems are central-station monitored per NFPA 72 and FDNY approval.

NYC Fire Alarm System Requirements by Occupancy Group

Before diving into the group-by-group breakdown, it’s important to note that the Building Code often ties fire alarm requirements to a building’s occupant load (OL), which is the number of people a space is designed to accommodate.

Occupant Load (OL) is determined under BC §1004 based on floor area and use, and it directly influences whether an alarm, sprinkler, or voice system is required.

Occupancy	When is a fire alarm system required?	Notes
A (Assembly)	Manual & automatic alarm where: OL ≥ 300 EVACS often required. Additional triggers vary by subclass. Example: A-2 cabaret ≥ 75 OL → manual system; A-2 OL ≥ 300 → add automatic system; A with a stage ≥ 75 OL → EVACS Presignal + EVACS: In A-1 with OL ≥ 300, and all other Group A with OL ≥ 1,000, activation must initiate a presignal at a constantly attended location, notify FDNY, and start EVACS live voice instructions	Manual boxes may be omitted when fully sprinklered except A-2 cabaret; when omitted, at least one box still required.
B (Business)	Manual & automatic alarm where: OL ≥ 500 total; >100 persons above/below exit discharge; or ambulatory care present. Partial smoke detection required if not sprinklered. “Large-area” B >100,000 sf in low-rise also has added detection + EVACS.	Standard manual-box placement (≤5 ft at exits).
E (Educational)	Manual & automatic alarm in all Group E; EVACS required; exception: EVACS not required if OL ≤100 (alarm must still sound).	Standard manual-box placement (≤5 ft at exits).
F (Factory / Industrial)	Manual & automatic when: 2+ stories and OL ≥ 100, or  ≥25 persons above/below exit discharge.	Standard manual-box placement (≤5 ft at exits).
H (High-hazard)	Manual & automatic in H-5 and where organic coatings are manufactured; extra smoke detection for certain hazards per FC. Additional detection per NYC Fire Code for specific materials.	Standard manual-box placement (≤5 ft at exits).
I (Institutional)	Manual & automatic; automatic smoke detection in specified areas (I-1, I-2 details) Notification per §907.5; see I-1/I-2 corridor and area coverage specifics.	Standard manual-box placement (≤5 ft at exits).
M (Mercantile)	Manual & automatic when any of: single fire area >12,000 sf, fire area >3 stories above grade, combined M areas >24,000 sf, below-grade fire area exceeds 1,500 sf. If not sprinklered: provide manual FA + partial-coverage automatic smoke or heat detection per NFPA 72. Large-area: >100,000 sf (highest occupied floor ≤75 ft) and covered malls >50,000 sf → automatic smoke detection  + EVACS.	Standard manual-box placement (≤5 ft at exits).
R-1 (Transient)	Provide manual fire alarm (activates notification); automatic smoke detection in public corridors (except where each unit exits directly to exterior); in-unit detection & notification with annunciation at a constantly attended location; dormitories: interconnect required smoke alarms to the building FA. Large R-1: >50 sleeping rooms above street level in buildings with highest occupied floor ≤ 75 ft → automatic smoke detection + EVACS	Standard manual-box placement (≤5 ft at exits).
R-2 (Multifamily)	In many non-student R-2s meeting listed conditions, a fire alarm system without notification appliances is required; student apartments have separate manual/automatic provisions. No EVACS in R-2 high-rise: for R-2 >75 ft, alarms signal central station only; provide one-way voice communication to dwelling units & stairs.	Manual boxes generally not required in typical non-student R-2 unless specifically triggered
S (Storage)	Manual & automatic when any: Group S fire area OL ≥300, or combined S OL ≥300 across floors. Large-area S (> 500,000 sf) also needs EVACS + automatic smoke detection.	Standard manual-box placement (≤5 ft at exits).

How Sprinklers Drive the Alarm Design

• Sprinkler presence adds automatic initiation (waterflow) to the fire alarm system and, in many occupancies, allows reduction of manual boxes, but one box is still required.

• BC 903 sets occupancy-specific sprinkler thresholds (e.g., Group I occupancy, high-rise triggers, certain S-1 motor-vehicle storage, mattress & upholstered furniture in M). Designers must check both 903 and 907 together.

• In New York City, sprinklers do not, by themselves, require a full building fire alarm system. The trigger for a building fire alarm is BC 907. When BC 907 does require a fire alarm, that system must supervise sprinkler control valves and waterflow under BC 903.4, and it must be central-station monitored (FDNY-approved). Unlike the model codes (IBC/IFC), which generally expect sprinkler supervision by a listed fire alarm control unit in most sprinklered buildings, NYC amends §903.4 to tie supervision to the presence of a required fire alarm system. Even when a building fire alarm isn’t required, §903.4.2 still mandates an exterior local waterflow alarm (e.g., bell/gong) on every sprinkler system; and if a building fire alarm system is installed for any reason, sprinkler actuation must automatically actuate that system

Common Issues

• Thinking sprinklers erase pull-station requirements. In NYC, sprinklers do not automatically remove manual boxes. Only where that occupancy’s §907.2 subsection explicitly allows it may boxes be reduced, and NYC still maintains at least one pull when an exception applies.

• Forgetting central-station monitoring. When §907 requires a fire alarm system, it must be monitored by an FDNY-approved supervising station (limited exceptions only).

• Overlooking occupant-load/area thresholds. Triggers hinge on OL and fire area math. Small changes in layout can flip the requirement.

• Misclassifying fire areas. Many thresholds reference “fire area” or combined fire areas on all floors. Get separations, ratings, and sprinkler zoning right before deciding triggers.

• Under-documenting for DOB/FDNY. BC §907.1 expects complete submittals that include, but are not limited to, the following: narrative/sequence of operations, riser and device layouts, and coordination with sprinkler shop drawings and ARCS (if applicable).

• Overlooking emergency/standby power. In NYC, FA systems must meet NFPA 72 battery capacity (typically 24-hr standby + 5-min alarm, or 15-min for EVACS) as adopted in Appendix Q; separately, specific life-safety loads (e.g., certain voice/alarm systems, smoke control, exit signs, etc.) require generator-backed emergency/standby power per BC §2702 and NYC EC.

BUILT Engineers Can Help

At BUILT Engineers we assist architects, engineers, contractors and property owners with:

• Code analysis and determination (which occupancy group, thresholds, exceptions apply)

• Fire‐alarm system design

• Plan review and submittal documentation for DOB and FDNY

• Coordination with mechanical, electrical, plumbing and fire-protection trades (MEP/FP integration)

• Permitting support and construction-phase review to ensure code-compliant installation

If your project involves a fire alarm system in NYC whether a new build, tenant improvement, or alteration/retrofit, contact our team today so we can help you navigate NYC fire alarm requirements and implement a practical, code‐compliant solution.