NV Fire Alarm cheat sheet

NFPA 72 is the installation, inspection, testing, and maintenance standard; NFPA 70 (NEC) governs wiring and power. Local Nevada amendments override where more stringent.

Protection types: conventional (zone-based, alarm = zone ID), addressable (device-level ID), and analog addressable (control unit polls analog values for sensitivity decisions).

Occupancy classifications drive detector selection: assembly, educational, residential, mercantile, business, industrial, storage, and hazardous.

Smoke detector spacing: 30 ft (9.1 m) maximum on smooth ceilings, 21 ft (6.4 m) for spot-type near walls/partitions per NFPA 72 spacing tables.

Heat detector spacing: 50 ft (15.2 m) for 135°F spot detectors on smooth ceilings; reduce per NFPA 72 Table 17.6.3.1 for ceiling height.

A system's alarm signal must reach notification appliances within 10 seconds in a protected premises system; notification appliance circuit voltage drop must be verified.

Elevator recall, HVAC shutdown, door release, and suppression interface are supervisory control functions distinct from alarm and trouble signals.

NFPA 72 requires a 20% spare capacity for initiating device circuits, notification circuits, and control unit capacity.

Ohm's law: V = I × R. Power: P = V × I = I²R. Voltage drop on a circuit: VD = 2 × L × I × R per 1,000 ft (copper resistance tables).

NFPA 72 requires that notification appliance circuits not exceed 10% voltage drop from the control unit to the last appliance.

Class A circuits return to the control unit (survive single open); Class B circuits do not return (single open loses downstream devices).

Class X circuits (addressable) provide isolation so a single fault does not disable the entire circuit; required in some high-rise and healthcare occupancies.

NFPA 70 Article 760 covers fire alarm wiring: NPLFA (non-power-limited) and PLFA (power-limited) circuit requirements, conductor types FPL, FPLR, FPLP.

FPLR (riser-rated) is required for vertical runs between floors; FPLP (plenum-rated) is required in environmental air spaces.

Surge protection and grounding: single-point ground at the control unit; isolated ground reference for addressable loops per manufacturer.

Battery calculations use manufacturer standby and alarm current draws plus a 20% aging/degradation factor and 5-minute alarm duration (or 15 minutes for voice evacuation).

Spot-type smoke detectors: ionization (fast-flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination/multi-criteria.

Duct smoke detectors are required where air handling units exceed 2,000 CFM and serve more than one story or more than 15,000 sq ft per NFPA 90A.

Heat detectors: fixed temperature (135°F or 194°F typical), rate-of-rise (15°F per minute), or combination.

Manual pull stations must be within 5 ft (1.5 m) of an exit door, mounted 42–48 in (1.07–1.22 m) AFF, and unobstructed.

Waterflow switches must alarm within 90 seconds of water flow; tamper switches are supervisory, not alarm, signals.

Projected beam and air-aspirating detectors have different spacing rules than spot detectors; beam detectors require 60 ft maximum spacing with specific mounting.

Addressable devices have unique addresses; conventional zones share a circuit and require end-of-line (EOL) resistors for supervision.

Detector spacing near walls: 4 in (100 mm) minimum from wall; 36 in (900 mm) clearance from HVAC diffusers; 3 ft from ceiling fans.

Audible appliances must produce at least 15 dBA above ambient or 5 dBA above maximum ambient for 60 seconds, whichever is greater, at 10 ft (3 m).

Public mode audible requirements: 65 dBA minimum at 10 ft, or 75 dBA at the pillow in sleeping areas (private mode).

Visible appliances: candela ratings per NFPA 72 Table 18.5.5.1; 15 cd minimum for typical rooms, higher for large spaces or corridors.

Wall-mounted visible appliances: 80 in (2.03 m) to 96 in (2.44 m) AFF; ceiling-mounted: within 24 in (610 mm) of ceiling.

Voice evacuation systems require intelligible voice (STI ≥ 0.50 or CIS ≥ 0.45) and speaker circuits verified for voltage drop and wattage.

Synchronization is required when multiple visible appliances are visible from any point; NAC synchronization modules or compatible control units.

NAC voltage drop calculation: VD = (total current × total loop resistance) must not exceed 10% of nominal voltage.

Notification appliance circuit supervision: open/short faults must annunciate as trouble within 200 seconds (per NFPA 72).

Control unit must be listed to UL 864 (fire alarm) or UL 2017 (accessory); combination systems require appropriate listings.

Primary power: 120 VAC dedicated circuit, marked "FIRE ALARM CIRCUIT CONTROL," with a lockable disconnect or breaker lock.

Secondary power: sealed lead-acid batteries sized for 24-hour standby plus 5 minutes alarm (15 minutes for voice); sealed batteries must be replaced every 4–5 years.

Battery charger must be capable of recharging batteries to 80% capacity within 24 hours of a discharge.

Control unit annunciation must distinguish alarm, supervisory, and trouble signals; trouble must sound within 200 seconds of fault.

Remote annunciators and addressable loop cards require separate power or supervision; verify with manufacturer load calculations.

Ground fault detection: control units must annunciate ground faults; isolated loops reduce nuisance ground faults.

Power supply load calculations: sum all device currents (standby and alarm), add 20% spare, compare to supply rating.

NFPA 72 Table 14.4.3.2 sets testing frequencies: monthly (some devices), quarterly, semiannual, annual, and 5-year intervals.

Annual testing: all initiating devices, notification appliances, control unit functions, batteries, and remote annunciators.

Monthly: inspection of control unit, battery terminals, and trouble signals; quarterly: waterflow and tamper switch tests.

Smoke detector sensitivity testing: annual per NFPA 72; detector must be within manufacturer's listed sensitivity range.

Test records must be retained and available to the AHJ; documentation includes device ID, test method, result, and tester.

Battery load test: annual; replace if capacity falls below 80% of rated capacity or manufacturer's threshold.

Impairment procedures: notify AHJ and occupants, post fire watch if system is out of service, and document restoration.

Acceptance testing: 100% of devices tested at initial acceptance; representative sampling allowed for periodic testing per NFPA 72.

Submittal package: floor plans, riser diagram, device legend, battery calculations, voltage drop calculations, and manufacturer cut sheets.

Plans must show device locations, spacing dimensions, circuit routing, conduit sizes, and control unit location.

Riser diagram must show all circuits, zones, addressable loops, and interfaces to other systems (suppression, HVAC, elevator).

NFPA 72 requires record of completion (Form 72-1) and record of inspection and testing at acceptance.

As-built drawings must reflect actual installed conditions; changes during construction require AHJ approval.

Sequence of operations matrix documents cause-and-effect for each alarm/supervisory/trouble condition.

Nevada requires plan submittal to the State Fire Marshal or local AHJ with licensed contractor information before installation.

Calculations must demonstrate battery capacity, NAC voltage drop, and standby/alarm current within listed limits.

Nevada Revised Statutes (NRS) Chapter 477 governs fire protection, including fire alarm system requirements and State Fire Marshal authority.

Nevada Administrative Code (NAC) Chapter 477 contains adopted fire and life safety codes; the State Fire Marshal adopts current editions of NFPA standards by reference.

Fire alarm contractors must be licensed by the Nevada State Contractors Board (NSCB) in the appropriate classification; low-voltage work may require a separate license.

Nevada requires permits and inspections for fire alarm installation; work without permit may result in stop-work orders and fines.

NFPA 72 and NFPA 1 (Fire Code) are adopted by reference; local jurisdictions may impose stricter requirements.

Nevada adopts the International Building Code (IBC) and International Fire Code (IFC) with state amendments; occupancy classification drives alarm requirements.

Contractors must maintain records of installation, testing, and maintenance and provide them to the AHJ upon request.

False alarm ordinances in Nevada jurisdictions may impose fees or penalties; proper maintenance and detector placement reduce false alarms.

Lockout/tagout (LOTO) procedures are required before working on energized circuits; verify absence of voltage with a tester.

Personal protective equipment: safety glasses, hard hat, hearing protection (for alarm testing), and arc-rated clothing where required.

Ladder safety: 3-point contact, 4:1 angle, secure footing; do not work on ladders near energized lines.

Fire alarm testing may require hearing protection; audible appliances can exceed 85 dBA in test mode.

Tool use: torque screwdrivers for terminal connections per manufacturer; verify conductor terminations to prevent loose connections.

Conduit bending and installation must follow NEC Chapter 3 and NFPA 72; support spacing per code.

Jobsite documentation: maintain as-built drawings, test records, and red-line markups; report changes to project manager.

Coordination with other trades: avoid conflicts with sprinkler piping, HVAC ducts, and electrical panels; maintain clear access to devices.