OK Fire Alarm Installer cheat sheet

NFPA 72 (National Fire Alarm and Signaling Code) governs design, installation, inspection, testing, and maintenance; the edition adopted by the local jurisdiction is the enforceable edition on a project.

NFPA 70 (NEC) Article 760 covers fire alarm wiring: Part II addresses non-power-limited fire alarm circuits (NPLFA) and Part III addresses power-limited fire alarm circuits (FPL).

Cable markings: FPL for general-use power-limited fire alarm cable, FPLR for riser, FPLP for plenum, and NPLF for non-power-limited fire alarm cable.

NFPA 101 (Life Safety Code) and the locally adopted fire code (IFC or state code) determine when a fire alarm system is required for a given occupancy.

Design and installation documents must be submitted to the authority having jurisdiction for review and approval before installation begins and before wiring is concealed.

Where two adopted documents conflict, the more restrictive requirement generally applies, and a written interpretation from the AHJ controls.

Most states require a licensed fire alarm or low-voltage contractor and a qualified (often NICET-certified) designer and tester to perform plan work and acceptance testing.

NFPA 72 requires the installing contractor to deliver documentation to the owner, including design drawings, calculations, as-builts, and inspection/testing records.

A protected premises system consists of initiating devices, notification appliances, a listed control unit, and primary plus secondary power sources.

Signal priority is alarm over supervisory over trouble; supervisory and trouble signals must be visibly and audibly distinct from alarm signals.

Class B circuits: a single open or ground fault annunciates a trouble but can prevent devices beyond the fault from operating.

Class A circuits: the pathway leaves the control unit and returns on a separate conductor, so a single open fault leaves all devices operational.

Pathway survivability Levels 0 through 4 describe how well circuits resist fire; higher levels use fire-rated cable, 2-hour enclosures, or redundant paths.

On smooth ceilings, spot-type smoke detectors are spaced no more than 30 ft apart and no more than 15 ft from any wall, about 900 sq ft per detector.

Heat detector spacing equals the detector's listed spacing on a smooth ceiling, reduced for ceiling heights above the listing and for joist or beam obstructions.

Detectors must be kept at least 3 ft from air supply diffusers and must not be placed in dead-air spaces such as the tops of stairwells or corners.

Conventional zones identify only the group of devices that alarmed; addressable signaling line circuits identify each device individually.

Ionization smoke detectors respond fastest to flaming fires with small particles; photoelectric detectors respond best to smoldering fires producing larger visible particles.

Heat detectors are fixed-temperature, rate-of-rise (commonly 15 degrees F per minute), or combination types, and may be restorable or nonrestorable.

Manual fire alarm boxes: operable portion 42 in to 48 in above finished floor, located within 5 ft of the exit doorway, and within 200 ft travel distance along the path of egress.

Waterflow switches must alarm within 90 seconds of flow equivalent to one sprinkler (not less than 10 gpm) and must not alarm on surges below that threshold.

Valve tamper switches are supervisory devices that must indicate off-normal within two revolutions of the handwheel or one-fifth of the valve travel.

Duct smoke detectors are required by mechanical code on air handling units of 2,000 cfm or greater and serve to shut down the unit, not to protect the occupied space.

Two-wire detectors must be listed as compatible with the specific control unit; an unlisted panel-detector combination can prevent proper alarm, reset, or supervision.

Beam, air-sampling, and video-based smoke detection are used where spot-type detectors are impractical, such as high ceilings, atria, and harsh environments.

Flame detectors (UV or IR) are used for high-hazard, fast-developing fires and require a clear line of sight to the protected hazard.

Public mode audibility requires 15 dBA above average ambient sound or 5 dBA above the maximum ambient lasting 60 seconds or more, whichever is greater.

Sleeping areas require 75 dBA at the pillow or 15 dBA above ambient, whichever is greater, and commercial sleeping rooms require a 520 Hz low-frequency alarm tone.

Visible appliances are rated in candela and selected from the room-size table; strobes in the same field of view must be synchronized to preserve effective warning.

Sound pressure at the minimum hearing distance from an audible appliance must not exceed 110 dBA, and must not exceed 120 dBA where a person may be present.

Voice evacuation systems must be designed for intelligibility, and speaker circuits must be arranged so a single fault does not silence the entire system.

Notification appliance circuit voltage-drop calculations must show every appliance receives at least its listed minimum operating voltage at the worst-case point.

Alarm signals must be distinctive and may not be used for non-emergency purposes; trouble and supervisory signals must be different from alarm signals.

Audible and visible appliances must be installed so that the coverage of each space meets the code-required sound level and candela coverage.

The control unit must be listed (UL 864) and installed in accordance with its listing, manufacturer instructions, and the approved design.

Circuit types include the initiating device circuit (IDC), notification appliance circuit (NAC), and signaling line circuit (SLC), each with its own supervision rules.

Class B circuits use an end-of-line resistor at the far end; Class A circuits use a return conductor to the control unit for fault tolerance.

Ground-fault detection is required, must annunciate as a trouble signal, and is typically indicated per circuit on addressable panels.

Addressable loops use isolator modules or built-in device isolation so a single short circuit does not disable the entire signaling line circuit.

Power-limited fire alarm conductors must be separated from non-power-limited conductors and other systems by at least 2 in of air or a listed barrier.

Splices and terminations must be made in listed, accessible enclosures; splicing with tape above a ceiling or in an inaccessible location is not permitted.

Emergency control functions, including elevator recall, HVAC shutdown, door release, and stairwell pressurization, are performed through listed relay or control modules.

Primary power must come from a dedicated branch circuit marked 'FIRE ALARM CIRCUIT CONTROL' at the disconnect, with a lockable disconnect and no ground-fault protection.

Secondary power is provided by sealed lead-acid batteries or a listed UPS and must be capable of carrying the system for the code-required duration.

Typical protected premises requirement is 24 hours of standby followed by 5 minutes of alarm; voice evacuation systems require 15 minutes of alarm.

Battery capacity formula: Ah = 1.2 x [(standby current x standby hours) + (alarm current x alarm hours)], where 1.2 adds a 20 percent aging margin.

Load totals must include panel standby and alarm current plus all notification appliance, module, and auxiliary device currents at their rated values.

The charging means must be able to restore the batteries to full charge within 48 hours after a full discharge.

Voltage-drop calculations must be repeated at end-of-discharge battery voltage, because that is the worst-case condition for appliance operation.

Batteries must be load-tested at the required interval, replaced when they fail, and have their terminals protected against shorting.

NFPA 72 Chapter 14 sets minimum inspection and testing frequencies; the AHJ or manufacturer instructions may require more frequent action.

Common frequencies: control equipment monthly inspection and annual test; smoke, heat, and duct detectors annual functional test; manual fire alarm boxes semiannual.

Waterflow switches are tested semiannually and valve supervisory switches quarterly, using the bypass or test valve provided.

Batteries receive a monthly visual inspection and an annual load or capacity test; a battery that fails the load test is replaced.

Smoke detector sensitivity or calibration checks follow the manufacturer's published instructions and the code edition in effect for the project.

Before testing, notify the monitoring company, building occupants, and the AHJ; after testing, verify restoration and confirm signals were received.

All results are documented on a record of inspection and testing with dates, devices tested, results, and the tester's signature.

When a system is impaired, the AHJ, owner, and monitoring company are notified and a fire watch or other approved mitigation is provided until restoration.

Work sequence: permit and plan review, rough-in inspection before concealment, final inspection, AHJ-witnessed acceptance test, then system turnover.

Required submittals include design drawings, sequence of operations, battery and voltage-drop calculations, manufacturer cut sheets, and as-built drawings.

The record of completion documents that the installation matches the approved design and is signed by the installing contractor and verified at acceptance.

Jobsite safety: OSHA fall protection at 6 ft, ladder inspection and three-point contact, lockout/tagout on panel power, and appropriate PPE.

Energized work follows NFPA 70E and manufacturer instructions; verify de-energized with a meter before touching conductors, then apply a lock and tag.

A written contract should define scope, exclusions, the code edition used for design, schedule, change-order process, warranty, and payment terms.

Maintain licensing, insurance, and technician certifications, and record any code deficiency found in writing to the owner and AHJ.

Central station or remote monitoring connections must be tested and documented, with account information and signal handling verified before turnover.