ID Fire Alarm cheat sheet

NFPA 72 is the installation, inspection, testing, and maintenance standard for fire detection and alarm systems; NFPA 70 (NEC) governs wiring methods, and NFPA 101 governs life-safety occupancy requirements.

NFPA 72 Chapter 9 addresses initiating device circuits and pathways; survivability of circuits serving notification and emergency communications is covered in Chapters 12 and 24 and requires 2-hour protection for Class X or Class N pathways in high-rise or partial evacuation designs.

Pathway Class designations: Class A circuits survive a single open, Class B do not; Class X adds survivability of both open and short conditions; Class N is the newer Ethernet-based pathway class for digital alarm communicator and emergency communications systems.

Initiating device circuits (IDCs) are classified by Style: Style B has an end-of-line resistor and no redundant path; Style D and Style E provide Class A redundancy, meaning an open circuit does not prevent alarm signal transmission from devices beyond the break.

NFPA 72 requires that alarm signal be manually or automatically initiated, and that a single open or ground fault on a Class A circuit does not prevent alarm annunciation; on Class B circuits a single open prevents alarms from devices beyond the break.

Spot-type smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; NFPA 72 permits 900 sq ft (84 sq m) maximum coverage per detector under smooth ceiling conditions, reduced by 0.7 factor for high ceilings.

Notification appliance circuits (NACs) must be supervised; a single open on a Class B NAC may silence all appliances beyond the break, so Class A is required where partial evacuation or relocation is a design strategy.

NFPA 72 Chapter 14 requires a record of completion (Form 72-1) and an inspection, testing, and maintenance record; the installation must be tested per Chapter 14 before acceptance, and periodic testing intervals range from monthly (battery inspection) to annual and semiannual tests depending on component type.

The Authority Having Jurisdiction (AHJ) enforces the code and may accept alternate methods; the designer of record is responsible for the design, and the contractor is responsible for installation per approved plans.

A fire alarm system has four functional components: initiating devices, notification appliances, control equipment, and the connecting pathways; the control unit processes signals and activates outputs.

System types include conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) and each device has a unique address for annunciation.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors are rate-of-rise or fixed-temperature and respond to thermal energy, not smoke.

A zone is a defined area of detection; NFPA 72 limits a conventional detection zone to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone for addressable systems where zone annunciation is required.

Alarm signal characteristics: temporal-3 pattern (three pulses, pause, repeat) is the standard audible fire alarm evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Two-stage or voice evacuation systems use a pre-signal (alert) followed by an evacuation signal; the pre-signal must be distinct from the evacuation signal and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract, and is the highest level of monitoring reliability.

Supervisory signals indicate off-normal conditions of system components (valve closed, low air pressure, pump off); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; the control unit must process and display the highest-priority condition and must not allow a lower-priority signal to mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings, detectors are spaced based on the slope, and the detector row is placed within 3 ft (0.9 m) of the peak for slopes over 10 degrees.

Beam smoke detectors are listed for specific spacing and must be installed per manufacturer instructions; projected beam detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems have a capacity over 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to a temperature increase of about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, and on the latch side of the door; they must be unobstructed and visible.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers and at least 4 in (0.1 m) from walls; they must not be installed in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; they must be installed on the sprinkler system and are supervised; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable initiating devices report their unique address; conventional devices report only a zone; a device's address must match the program and the as-built documentation.

Audible notification must produce a sound level at least 15 dBA above the ambient sound level or 5 dBA above the maximum sound level lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation; a lower level may be permitted only with AHJ approval and specific conditions.

Visible notification appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected based on room size and mounting height, with 15 cd minimum for small rooms and higher candela for larger spaces.

The visible appliance must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor, and the coverage area depends on the candela rating and the mounting height; a 15 cd appliance covers a smaller area than a 110 cd appliance.

Audible appliances must be listed and marked with their dBA rating at 10 ft; the dBA rating at the pillow is calculated using the inverse square law: each doubling of distance reduces sound by 6 dB.

Voice evacuation systems must produce intelligible voice messages; intelligibility is measured by the Speech Transmission Index (STI) or Common Intelligibility Scale (CIS), with a minimum acceptable value of 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and must be capable of operating all appliances simultaneously; the NAC must be sized so that the total current does not exceed the panel's rated output, and voltage drop must be calculated to ensure the last appliance receives rated voltage.

Notification appliances must be synchronized when more than one appliance is visible in the same area; synchronization prevents conflicting flash patterns and is required for visible appliances in the same view.

The fire alarm control panel (FACP) must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary power supply (battery) capable of operating the system for 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be sized to the calculated amp-hour requirement and must be tested under load.

Ground fault detection is required on the system; a ground fault on a supervised circuit must annunciate a trouble condition; the panel must detect and annunciate ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

Addressable SLC circuits use a signaling line circuit that carries both power and data; the SLC must be supervised for opens, shorts, and ground faults; the panel must be able to communicate with each device on the loop.

Relay outputs are used for controlling auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function, and the relay must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch must silence the notification appliances but not the alarm processing; a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals; they must be located where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing of all initiating devices, notification appliances, and control functions; the test must verify that each device produces the correct signal and that the panel annunciates the correct zone and device.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors are tested with a heat source or a listed test method; pull stations are tested by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and control panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels must be measured with a sound level meter at the required locations, and visible appliances must be observed for proper flash rate and synchronization.

Testing must be documented on the inspection and testing form; records must include the date, the device tested, the test method, the result, and the name of the tester; records must be retained for at least one year or as required by the AHJ.

A pre-test walkthrough verifies that devices are installed per plans and that addresses match the program; discrepancies must be corrected before functional testing to avoid false failures.

Impedance and voltage-drop tests on NACs verify that the last appliance receives the rated voltage; a voltage drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble condition indicates a fault that may impair system operation, and the system must be restored to normal operation as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced; cleaning intervals depend on the environment.

False alarms can be reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or a ground fault locator can identify the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested to verify proper operation, and the maintenance record must be updated with the date, the work performed, and the result.

The system must be maintained in accordance with the manufacturer's instructions and NFPA 72; a maintenance program must include inspection, testing, and corrective action, and records must be available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents that the system was installed per the approved plans and tested per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration; they must be updated whenever the system is modified.

The inspection and testing record must include the date, the devices tested, the test method, the results, and the tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including the date, the work performed, the parts replaced, and the result; it supports the system's history and helps identify recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance; it provides a chronological history for troubleshooting and for AHJ review.

Notification appliance circuit calculations (voltage drop and current) must be documented and retained; they demonstrate that the design meets the listing and code requirements.

Reports to the AHJ must be submitted as required by the local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.

NFPA 72 covers installation, inspection, testing, and maintenance of fire alarm systems; NFPA 70 (NEC) covers wiring methods; NFPA 101 covers life-safety occupancy requirements.

Pathway Class A survives a single open; Class B does not; Class X adds short-circuit survivability; Class N is the Ethernet-based pathway class.

IDC Styles: Style B uses an end-of-line resistor with no redundancy; Style D and Style E provide Class A redundancy so a single open does not block alarms beyond the break.

Spot smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; maximum coverage is 900 sq ft (84 sq m) per detector.

NACs must be supervised; Class A is required where partial evacuation or relocation is a design strategy because a Class B open may silence appliances beyond the break.

NFPA 72 Chapter 14 requires a record of completion and an inspection, testing, and maintenance record; testing intervals range from monthly to annual depending on component type.

The AHJ enforces the code and may accept alternate methods; the designer of record is responsible for design, and the contractor is responsible for installation per approved plans.

Temporal-3 is the standard evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Four functional components: initiating devices, notification appliances, control equipment, and connecting pathways; the control unit processes signals and activates outputs.

System types: conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) with unique device addresses.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors respond to thermal energy, not smoke.

A conventional detection zone is limited to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone where zone annunciation is required.

Two-stage or voice evacuation systems use a pre-signal followed by an evacuation signal; the pre-signal must be distinct and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract.

Supervisory signals indicate off-normal component conditions (valve closed, low air pressure); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; a lower-priority signal must not mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings over 10 degrees, the detector row is placed within 3 ft (0.9 m) of the peak.

Projected beam smoke detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems exceed 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, on the latch side, and unobstructed.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers, at least 4 in (0.1 m) from walls, and not in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable devices report a unique address; conventional devices report only a zone; the address must match the program and the as-built documentation.

Audible notification must produce at least 15 dBA above ambient or 5 dBA above the maximum sound lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation.

Visible appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected by room size and mounting height, with 15 cd minimum for small rooms.

Visible appliances must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor; the coverage area depends on the candela rating and mounting height.

Audible appliances must be listed and marked with their dBA rating at 10 ft; each doubling of distance reduces sound by 6 dB (inverse square law).

Voice evacuation systems must be intelligible; the minimum acceptable value is 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and capable of operating all appliances simultaneously; total current must not exceed the panel's rated output, and voltage drop must be calculated.

Notification appliances must be synchronized when more than one appliance is visible in the same area to prevent conflicting flash patterns.

The FACP must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary supply capable of 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be tested under load.

Ground fault detection is required; a ground fault on a supervised circuit must annunciate a trouble; the panel must detect ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

The SLC carries both power and data and must be supervised for opens, shorts, and ground faults; the panel must communicate with each device on the loop.

Relay outputs control auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function and must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch silences notification appliances but not alarm processing, and a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing all initiating devices, notification appliances, and control functions and verifying correct zone and device annunciation.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors with a heat source or listed method; pull stations by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels are measured with a sound level meter, and visible appliances are observed for flash rate and synchronization.

Testing must be documented on the inspection and testing form with the date, device tested, test method, result, and tester's name; records must be retained as required by the AHJ.

A pre-test walkthrough verifies devices are installed per plans and addresses match the program; discrepancies must be corrected before functional testing.

Impedance and voltage-drop tests on NACs verify that the last appliance receives rated voltage; a drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble indicates a fault that may impair operation, and the system must be restored to normal as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced.

False alarms are reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or ground fault locator identifies the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested and the maintenance record updated with the date, work performed, and result.

The system must be maintained per the manufacturer's instructions and NFPA 72; the program must include inspection, testing, and corrective action, with records available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents installation per approved plans and testing per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration, and must be updated whenever the system is modified.

The inspection and testing record must include the date, devices tested, test method, results, and tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including date, work performed, parts replaced, and result; it supports the system history and identifies recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance, providing a chronological history for troubleshooting and AHJ review.

NAC calculations (voltage drop and current) must be documented and retained to demonstrate that the design meets listing and code requirements.

Reports to the AHJ must be submitted as required by local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.

NFPA 72 is the installation, inspection, testing, and maintenance standard; NFPA 70 (NEC) governs wiring methods; NFPA 101 governs life-safety occupancy requirements.

Pathway Class A survives a single open; Class B does not; Class X adds short-circuit survivability; Class N is the Ethernet-based pathway class.

IDC Styles: Style B uses an end-of-line resistor with no redundancy; Style D and Style E provide Class A redundancy so a single open does not block alarms beyond the break.

Spot smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; maximum coverage is 900 sq ft (84 sq m) per detector.

NACs must be supervised; Class A is required where partial evacuation or relocation is a design strategy because a Class B open may silence appliances beyond the break.

NFPA 72 Chapter 14 requires a record of completion and an inspection, testing, and maintenance record; testing intervals range from monthly to annual depending on component type.

The AHJ enforces the code and may accept alternate methods; the designer of record is responsible for design, and the contractor is responsible for installation per approved plans.

Temporal-3 is the standard evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Four functional components: initiating devices, notification appliances, control equipment, and connecting pathways; the control unit processes signals and activates outputs.

System types: conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) with unique device addresses.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors respond to thermal energy, not smoke.

A conventional detection zone is limited to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone where zone annunciation is required.

Two-stage or voice evacuation systems use a pre-signal followed by an evacuation signal; the pre-signal must be distinct and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract.

Supervisory signals indicate off-normal component conditions (valve closed, low air pressure); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; a lower-priority signal must not mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings over 10 degrees, the detector row is placed within 3 ft (0.9 m) of the peak.

Projected beam smoke detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems exceed 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, on the latch side, and unobstructed.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers, at least 4 in (0.1 m) from walls, and not in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable devices report a unique address; conventional devices report only a zone; the address must match the program and the as-built documentation.

Audible notification must produce at least 15 dBA above ambient or 5 dBA above the maximum sound lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation.

Visible appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected by room size and mounting height, with 15 cd minimum for small rooms.

Visible appliances must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor; the coverage area depends on the candela rating and mounting height.

Audible appliances must be listed and marked with their dBA rating at 10 ft; each doubling of distance reduces sound by 6 dB (inverse square law).

Voice evacuation systems must be intelligible; the minimum acceptable value is 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and capable of operating all appliances simultaneously; total current must not exceed the panel's rated output, and voltage drop must be calculated.

Notification appliances must be synchronized when more than one appliance is visible in the same area to prevent conflicting flash patterns.

The FACP must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary supply capable of 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be tested under load.

Ground fault detection is required; a ground fault on a supervised circuit must annunciate a trouble; the panel must detect ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

The SLC carries both power and data and must be supervised for opens, shorts, and ground faults; the panel must communicate with each device on the loop.

Relay outputs control auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function and must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch silences notification appliances but not alarm processing, and a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing all initiating devices, notification appliances, and control functions and verifying correct zone and device annunciation.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors with a heat source or listed method; pull stations by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels are measured with a sound level meter, and visible appliances are observed for flash rate and synchronization.

Testing must be documented on the inspection and testing form with the date, device tested, test method, result, and tester's name; records must be retained as required by the AHJ.

A pre-test walkthrough verifies devices are installed per plans and addresses match the program; discrepancies must be corrected before functional testing.

Impedance and voltage-drop tests on NACs verify that the last appliance receives rated voltage; a drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble indicates a fault that may impair operation, and the system must be restored to normal as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced.

False alarms are reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or ground fault locator identifies the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested and the maintenance record updated with the date, work performed, and result.

The system must be maintained per the manufacturer's instructions and NFPA 72; the program must include inspection, testing, and corrective action, with records available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents installation per approved plans and testing per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration, and must be updated whenever the system is modified.

The inspection and testing record must include the date, devices tested, test method, results, and tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including date, work performed, parts replaced, and result; it supports the system history and identifies recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance, providing a chronological history for troubleshooting and AHJ review.

NAC calculations (voltage drop and current) must be documented and retained to demonstrate that the design meets listing and code requirements.

Reports to the AHJ must be submitted as required by local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.

NFPA 72 covers installation, inspection, testing, and maintenance; NFPA 70 (NEC) governs wiring methods; NFPA 101 governs life-safety occupancy requirements.

Pathway Class A survives a single open; Class B does not; Class X adds short-circuit survivability; Class N is the Ethernet-based pathway class.

IDC Styles: Style B uses an end-of-line resistor with no redundancy; Style D and Style E provide Class A redundancy so a single open does not block alarms beyond the break.

Spot smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; maximum coverage is 900 sq ft (84 sq m) per detector.

NACs must be supervised; Class A is required where partial evacuation or relocation is a design strategy because a Class B open may silence appliances beyond the break.

NFPA 72 Chapter 14 requires a record of completion and an inspection, testing, and maintenance record; testing intervals range from monthly to annual depending on component type.

The AHJ enforces the code and may accept alternate methods; the designer of record is responsible for design, and the contractor is responsible for installation per approved plans.

Temporal-3 is the standard evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Four functional components: initiating devices, notification appliances, control equipment, and connecting pathways; the control unit processes signals and activates outputs.

System types: conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) with unique device addresses.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors respond to thermal energy, not smoke.

A conventional detection zone is limited to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone where zone annunciation is required.

Two-stage or voice evacuation systems use a pre-signal followed by an evacuation signal; the pre-signal must be distinct and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract.

Supervisory signals indicate off-normal component conditions (valve closed, low air pressure); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; a lower-priority signal must not mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings over 10 degrees, the detector row is placed within 3 ft (0.9 m) of the peak.

Projected beam smoke detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems exceed 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, on the latch side, and unobstructed.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers, at least 4 in (0.1 m) from walls, and not in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable devices report a unique address; conventional devices report only a zone; the address must match the program and the as-built documentation.

Audible notification must produce at least 15 dBA above ambient or 5 dBA above the maximum sound lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation.

Visible appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected by room size and mounting height, with 15 cd minimum for small rooms.

Visible appliances must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor; the coverage area depends on the candela rating and mounting height.

Audible appliances must be listed and marked with their dBA rating at 10 ft; each doubling of distance reduces sound by 6 dB (inverse square law).

Voice evacuation systems must be intelligible; the minimum acceptable value is 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and capable of operating all appliances simultaneously; total current must not exceed the panel's rated output, and voltage drop must be calculated.

Notification appliances must be synchronized when more than one appliance is visible in the same area to prevent conflicting flash patterns.

The FACP must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary supply capable of 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be tested under load.

Ground fault detection is required; a ground fault on a supervised circuit must annunciate a trouble; the panel must detect ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

The SLC carries both power and data and must be supervised for opens, shorts, and ground faults; the panel must communicate with each device on the loop.

Relay outputs control auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function and must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch silences notification appliances but not alarm processing, and a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing all initiating devices, notification appliances, and control functions and verifying correct zone and device annunciation.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors with a heat source or listed method; pull stations by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels are measured with a sound level meter, and visible appliances are observed for flash rate and synchronization.

Testing must be documented on the inspection and testing form with the date, device tested, test method, result, and tester's name; records must be retained as required by the AHJ.

A pre-test walkthrough verifies devices are installed per plans and addresses match the program; discrepancies must be corrected before functional testing.

Impedance and voltage-drop tests on NACs verify that the last appliance receives rated voltage; a drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble indicates a fault that may impair operation, and the system must be restored to normal as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced.

False alarms are reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or ground fault locator identifies the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested and the maintenance record updated with the date, work performed, and result.

The system must be maintained per the manufacturer's instructions and NFPA 72; the program must include inspection, testing, and corrective action, with records available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents installation per approved plans and testing per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration, and must be updated whenever the system is modified.

The inspection and testing record must include the date, devices tested, test method, results, and tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including date, work performed, parts replaced, and result; it supports the system history and identifies recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance, providing a chronological history for troubleshooting and AHJ review.

NAC calculations (voltage drop and current) must be documented and retained to demonstrate that the design meets listing and code requirements.

Reports to the AHJ must be submitted as required by local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.

NFPA 72 covers installation, inspection, testing, and maintenance; NFPA 70 (NEC) governs wiring methods; NFPA 101 governs life-safety occupancy requirements.

Pathway Class A survives a single open; Class B does not; Class X adds short-circuit survivability; Class N is the Ethernet-based pathway class.

IDC Styles: Style B uses an end-of-line resistor with no redundancy; Style D and Style E provide Class A redundancy so a single open does not block alarms beyond the break.

Spot smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; maximum coverage is 900 sq ft (84 sq m) per detector.

NACs must be supervised; Class A is required where partial evacuation or relocation is a design strategy because a Class B open may silence appliances beyond the break.

NFPA 72 Chapter 14 requires a record of completion and an inspection, testing, and maintenance record; testing intervals range from monthly to annual depending on component type.

The AHJ enforces the code and may accept alternate methods; the designer of record is responsible for design, and the contractor is responsible for installation per approved plans.

Temporal-3 is the standard evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Four functional components: initiating devices, notification appliances, control equipment, and connecting pathways; the control unit processes signals and activates outputs.

System types: conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) with unique device addresses.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors respond to thermal energy, not smoke.

A conventional detection zone is limited to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone where zone annunciation is required.

Two-stage or voice evacuation systems use a pre-signal followed by an evacuation signal; the pre-signal must be distinct and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract.

Supervisory signals indicate off-normal component conditions (valve closed, low air pressure); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; a lower-priority signal must not mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings over 10 degrees, the detector row is placed within 3 ft (0.9 m) of the peak.

Projected beam smoke detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems exceed 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, on the latch side, and unobstructed.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers, at least 4 in (0.1 m) from walls, and not in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable devices report a unique address; conventional devices report only a zone; the address must match the program and the as-built documentation.

Audible notification must produce at least 15 dBA above ambient or 5 dBA above the maximum sound lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation.

Visible appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected by room size and mounting height, with 15 cd minimum for small rooms.

Visible appliances must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor; the coverage area depends on the candela rating and mounting height.

Audible appliances must be listed and marked with their dBA rating at 10 ft; each doubling of distance reduces sound by 6 dB (inverse square law).

Voice evacuation systems must be intelligible; the minimum acceptable value is 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and capable of operating all appliances simultaneously; total current must not exceed the panel's rated output, and voltage drop must be calculated.

Notification appliances must be synchronized when more than one appliance is visible in the same area to prevent conflicting flash patterns.

The FACP must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary supply capable of 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be tested under load.

Ground fault detection is required; a ground fault on a supervised circuit must annunciate a trouble; the panel must detect ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

The SLC carries both power and data and must be supervised for opens, shorts, and ground faults; the panel must communicate with each device on the loop.

Relay outputs control auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function and must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch silences notification appliances but not alarm processing, and a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing all initiating devices, notification appliances, and control functions and verifying correct zone and device annunciation.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors with a heat source or listed method; pull stations by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels are measured with a sound level meter, and visible appliances are observed for flash rate and synchronization.

Testing must be documented on the inspection and testing form with the date, device tested, test method, result, and tester's name; records must be retained as required by the AHJ.

A pre-test walkthrough verifies devices are installed per plans and addresses match the program; discrepancies must be corrected before functional testing.

Impedance and voltage-drop tests on NACs verify that the last appliance receives rated voltage; a drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble indicates a fault that may impair operation, and the system must be restored to normal as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced.

False alarms are reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or ground fault locator identifies the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested and the maintenance record updated with the date, work performed, and result.

The system must be maintained per the manufacturer's instructions and NFPA 72; the program must include inspection, testing, and corrective action, with records available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents installation per approved plans and testing per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration, and must be updated whenever the system is modified.

The inspection and testing record must include the date, devices tested, test method, results, and tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including date, work performed, parts replaced, and result; it supports the system history and identifies recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance, providing a chronological history for troubleshooting and AHJ review.

NAC calculations (voltage drop and current) must be documented and retained to demonstrate that the design meets listing and code requirements.

Reports to the AHJ must be submitted as required by local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.

NFPA 72 covers installation, inspection, testing, and maintenance; NFPA 70 (NEC) governs wiring methods; NFPA 101 governs life-safety occupancy requirements.

Pathway Class A survives a single open; Class B does not; Class X adds short-circuit survivability; Class N is the Ethernet-based pathway class.

IDC Styles: Style B uses an end-of-line resistor with no redundancy; Style D and Style E provide Class A redundancy so a single open does not block alarms beyond the break.

Spot smoke detector spacing is 30 ft (9.1 m) on smooth ceilings, with the first detector within 15 ft (4.6 m) of any wall; maximum coverage is 900 sq ft (84 sq m) per detector.

NACs must be supervised; Class A is required where partial evacuation or relocation is a design strategy because a Class B open may silence appliances beyond the break.

NFPA 72 Chapter 14 requires a record of completion and an inspection, testing, and maintenance record; testing intervals range from monthly to annual depending on component type.

The AHJ enforces the code and may accept alternate methods; the designer of record is responsible for design, and the contractor is responsible for installation per approved plans.

Temporal-3 is the standard evacuation signal; temporal-4 is used for CO alarms; a continuous signal is not the standard evacuation pattern.

Four functional components: initiating devices, notification appliances, control equipment, and connecting pathways; the control unit processes signals and activates outputs.

System types: conventional (zone-based), addressable (device-level identification), and hybrid; addressable systems use a signaling line circuit (SLC) with unique device addresses.

Detector types: ionization (fast flaming fires, small particles), photoelectric (smoldering fires, larger particles), and combination; heat detectors respond to thermal energy, not smoke.

A conventional detection zone is limited to 1,000 sq ft (93 sq m) and a maximum of 25 devices per zone where zone annunciation is required.

Two-stage or voice evacuation systems use a pre-signal followed by an evacuation signal; the pre-signal must be distinct and must not exceed 180 seconds before evacuation if not acknowledged.

A supervising station monitors alarm, supervisory, and trouble signals; central station service requires listed equipment, a listed central station, and a contract.

Supervisory signals indicate off-normal component conditions (valve closed, low air pressure); trouble signals indicate a fault in the system itself (open circuit, ground fault, battery failure).

Priority of signals: alarm signals take precedence over supervisory and trouble signals; a lower-priority signal must not mask an alarm.

Smoke detector spacing on smooth ceilings is 30 ft (9.1 m); on sloped ceilings over 10 degrees, the detector row is placed within 3 ft (0.9 m) of the peak.

Projected beam smoke detectors are spaced per listing, often up to 60 ft (18.3 m) apart, and require alignment testing.

Duct smoke detectors are required where air-handling systems exceed 2,000 cfm (0.94 cu m/s) to shut down the unit and prevent smoke spread; they are not a substitute for area detection.

Heat detectors: fixed-temperature units are rated typically at 135°F to 194°F; rate-of-rise units respond to about 15°F per minute; combination units provide both responses.

Manual pull stations must be mounted 42 to 48 in (1.07 to 1.22 m) above the floor, within 5 ft (1.5 m) of the exit door, on the latch side, and unobstructed.

Detectors must be at least 3 ft (0.9 m) from air supply diffusers, at least 4 in (0.1 m) from walls, and not in dead air spaces or within 3 ft of ceiling fans.

Waterflow switches are initiating devices that detect sprinkler flow; a waterflow alarm must be annunciated within 90 seconds of flow.

Sprinkler supervisory devices include valve tamper switches (supervise the open position of control valves) and low-air-pressure switches; tamper switches are required on valves that control waterflow.

Addressable devices report a unique address; conventional devices report only a zone; the address must match the program and the as-built documentation.

Audible notification must produce at least 15 dBA above ambient or 5 dBA above the maximum sound lasting 60 seconds, whichever is greater, measured at 10 ft (3 m) from the appliance.

In sleeping areas, the sound level must be at least 75 dBA at the pillow level, and the temporal-3 pattern must be used for evacuation.

Visible appliances must be installed in public and common areas and in sleeping areas per accessibility requirements; candela ratings are selected by room size and mounting height, with 15 cd minimum for small rooms.

Visible appliances must be mounted 80 to 96 in (2.03 to 2.44 m) above the floor; the coverage area depends on the candela rating and mounting height.

Audible appliances must be listed and marked with their dBA rating at 10 ft; each doubling of distance reduces sound by 6 dB (inverse square law).

Voice evacuation systems must be intelligible; the minimum acceptable value is 0.50 STI or 0.70 CIS.

NAC circuits must be supervised and capable of operating all appliances simultaneously; total current must not exceed the panel's rated output, and voltage drop must be calculated.

Notification appliances must be synchronized when more than one appliance is visible in the same area to prevent conflicting flash patterns.

The FACP must be listed and installed per NFPA 72; it provides power, supervises circuits, and processes signals; it must have a secondary supply capable of 24 hours of standby plus 5 minutes of alarm.

Battery sizing: calculate standby current for 24 hours plus alarm current for 5 minutes, then apply a 20% derating factor for aging; the battery must be tested under load.

Ground fault detection is required; a ground fault on a supervised circuit must annunciate a trouble; the panel must detect ground faults on the SLC, NAC, and power circuits.

Circuit supervision: an open or short on a Class B circuit annunciates a trouble; a Class A circuit continues to operate beyond a single open; the panel must annunciate the specific circuit and zone.

The SLC carries both power and data and must be supervised for opens, shorts, and ground faults; the panel must communicate with each device on the loop.

Relay outputs control auxiliary functions such as door holders, dampers, and elevators; they must be supervised if they perform a fire-safety function and must be listed for the application.

The panel must be capable of being reset, silenced, and tested; the silence switch silences notification appliances but not alarm processing, and a subsequent alarm must resound.

Remote annunciators must be supervised and must display alarm, supervisory, and trouble signals where they can be observed by responding personnel.

Acceptance testing per NFPA 72 Chapter 14 requires testing all initiating devices, notification appliances, and control functions and verifying correct zone and device annunciation.

Smoke detectors are tested with listed aerosol or calibrated test gas; heat detectors with a heat source or listed method; pull stations by operating the mechanism and verifying the alarm.

Battery tests include a load test to verify capacity; the battery must be tested annually and replaced when it fails the load test or reaches the manufacturer's recommended service life (typically 3 to 5 years).

Periodic testing intervals: monthly inspection of batteries and panel indicators; semiannual testing of duct detectors and waterflow switches; annual testing of all initiating devices, notification appliances, and control functions.

Notification appliance testing must verify audibility and visibility; sound pressure levels are measured with a sound level meter, and visible appliances are observed for flash rate and synchronization.

Testing must be documented on the inspection and testing form with the date, device tested, test method, result, and tester's name; records must be retained as required by the AHJ.

A pre-test walkthrough verifies devices are installed per plans and addresses match the program; discrepancies must be corrected before functional testing.

Impedance and voltage-drop tests on NACs verify that the last appliance receives rated voltage; a drop exceeding the manufacturer's limit requires larger conductors or a different circuit design.

Trouble signals must be investigated and corrected promptly; a trouble indicates a fault that may impair operation, and the system must be restored to normal as soon as practicable.

Common trouble causes: open circuit (broken wire, loose terminal), short circuit (damaged insulation, water intrusion), ground fault (wire contacting conduit or ground), and device failure (dirty detector, failed appliance).

Dirty smoke detectors cause false alarms; detectors must be cleaned per manufacturer instructions, and a detector that cannot be cleaned must be replaced.

False alarms are reduced by proper detector selection (photoelectric in smoldering environments), proper placement (away from diffusers and cooking areas), and regular maintenance.

Battery maintenance includes checking terminals for corrosion, verifying charging voltage, and testing under load; a battery that does not hold a charge must be replaced, not just recharged.

Ground faults are located by isolating circuits section by section; a clamp-on ammeter or ground fault locator identifies the circuit with the fault; the fault must be repaired, not just reset.

After any maintenance or repair, the affected circuits must be retested and the maintenance record updated with the date, work performed, and result.

The system must be maintained per the manufacturer's instructions and NFPA 72; the program must include inspection, testing, and corrective action, with records available to the AHJ.

The record of completion (NFPA 72 Form 72-1) documents installation per approved plans and testing per Chapter 14; it must be signed by the contractor and the AHJ representative.

As-built drawings must reflect the actual installation, including device locations, addresses, circuit routing, and panel configuration, and must be updated whenever the system is modified.

The inspection and testing record must include the date, devices tested, test method, results, and tester's name; it must be retained and made available to the AHJ.

The maintenance record must document all maintenance and repairs, including date, work performed, parts replaced, and result; it supports the system history and identifies recurring problems.

Sequence of operations documentation describes how the system responds to each input (alarm, supervisory, trouble) and which outputs are activated; it must match the programmed system.

A written logbook should record all events, including alarms, troubles, tests, and maintenance, providing a chronological history for troubleshooting and AHJ review.

NAC calculations (voltage drop and current) must be documented and retained to demonstrate that the design meets listing and code requirements.

Reports to the AHJ must be submitted as required by local code; failure to maintain records can result in citations and may affect insurance and occupancy approvals.