NICET Fire Alarm key terms

The official or organization responsible for reviewing and approving fire alarm plans, installations, and tests. The AHJ enforces the adopted code and may be a fire marshal, building official, or their designee.

Equipment that has been evaluated by a nationally recognized testing laboratory, such as UL, and published on a list confirming it meets a specific standard. Fire alarm devices generally must be listed for their intended use.

Accepted by the authority having jurisdiction as meeting the applicable code or standard. Approval is a local determination and is separate from, though often based on, listing by a testing laboratory.

The National Fire Alarm and Signaling Code, a model code that covers the design, installation, inspection, testing, and maintenance of fire detection and alarm systems. It is commonly adopted into law by states and localities.

The article of the National Electrical Code that governs fire alarm system wiring, including conductor types, installation methods, and the separation of power-limited and non-power-limited circuits.

Detailed working drawings prepared by the contractor showing device locations, wiring routes, conduit sizes, and panel details. They are submitted for review before installation and become the basis for field work.

A form required by NFPA 72 that documents the installed system matches the approved design, lists devices and circuits, and is signed by the installing contractor and owner's representative.

Drawings revised after installation to show the actual installed locations of devices, routing of conduit, and any field changes from the original design. They are used for future maintenance and modifications.

A written description of how the fire alarm system responds to alarm, supervisory, and trouble conditions, including which outputs activate and in what order. It defines the intended cause-and-effect logic.

The process where the authority having jurisdiction or a design professional examines submitted drawings and calculations for code compliance before construction begins. Comments must be resolved before installation.

A defined area or group of initiating devices that the control unit identifies by a single common designation, such as a floor or room group. It helps responders locate the source of an alarm.

A defined area served by the same group of notification appliances, such as a floor or building section. Appliances in a zone are typically activated together by the control unit.

The circuit that connects automatic detectors and manual pull stations to the fire alarm control unit. It is supervised so opens, shorts, and grounds are annunciated as trouble conditions.

The circuit that supplies power to horns, strobes, speakers, and other notification appliances. It is supervised and usually power-limited, and must be sized for voltage drop.

A fire alarm system in which each initiating device and module has a unique address, so the control unit can identify the specific device that alarms or faults rather than only the circuit.

A fire alarm system that groups devices on circuits or zones; the control unit reports the zone rather than the individual device. Devices on a zone are usually wired in parallel with an end-of-line resistor.

A smoke detector whose sensing element samples air at a single point, as opposed to a beam or air-sampling detector. Its coverage depends on ceiling height, air movement, and spacing rules.

A detector designed for mounting on an HVAC duct so it samples the air stream and, on alarm, can shut down fans or close dampers. It is not a substitute for area smoke detection.

A device that responds to a rise in temperature, either fixed-temperature, rate-of-rise, or a combination. It is generally slower than smoke detection and used where smoke detectors are unsuitable.

The maximum permitted distance between detectors, set by NFPA 72 tables based on detector type, ceiling height, and ceiling configuration. Spacing limits are not the same as the actual area each detector covers.

The sound pressure level of an alarm signal in an occupied area. NFPA 72 requires it to exceed the ambient sound level by a specified margin and meet minimum levels in sleeping areas.

The degree to which a voice evacuation message can be understood by occupants, separate from whether it is loud enough. It is affected by reverberation, background noise, and speaker placement.

A strobe or combination appliance rated in candela, the unit of luminous intensity. NFPA 72 and accessibility standards set minimum candela ratings for rooms, corridors, and sleeping areas.

A rating of the wiring path between system components based on how it performs under fault conditions. Class A provides a redundant return path; Class B does not; Class X adds fault isolation.

The central panel that receives signals from initiating devices, processes the logic, supplies power, and controls notification appliances and other outputs. It also annunciates trouble and supervisory conditions.

A single-line schematic showing the vertical and horizontal arrangement of circuits, devices, and panels in a fire alarm system. It is used for design review, installation, and troubleshooting.

A resistor installed at the far end of a supervised conventional circuit that provides a known normal current. The control unit detects opens, shorts, and grounds by changes in that current.

A circuit continuously monitored by the control unit for abnormal conditions such as opens, short circuits, and grounds. Supervision ensures wiring faults are annunciated rather than leaving the system silently impaired.

A calculation of the voltage lost along conductors due to resistance, used to confirm that notification appliances receive at least their rated minimum voltage at the end of the circuit.

A calculation that sizes standby batteries to power the system during a utility outage and then support the alarm load for a required duration, accounting for aging and derating factors.

The process of sealing openings where cables or conduits penetrate fire-rated walls, floors, or ceilings, using listed materials to restore the assembly's fire resistance rating.

Cable listed for installation in air-handling spaces, having low smoke and flame spread characteristics. It is marked accordingly, such as CMP or FPLP, and required where the ceiling cavity is used for return air.

A circuit whose power is limited to levels that reduce the risk of fire and electric shock, allowing different wiring methods. Fire alarm IDCs and NACs are often power-limited and must be separated from non-power-limited wiring.

A test performed after installation to verify the system operates as designed and complies with code, witnessed by the authority having jurisdiction or its representative. It precedes the system being placed in service.

A test that measures a smoke detector's response to a calibrated aerosol or test device and compares it to the manufacturer's listed sensitivity range. Detectors outside the range must be cleaned or replaced.

A control unit mode that lets one person test initiating devices in the field while the panel records and later reports the results, reducing the need for a second person at the panel.

A condition in which a fire alarm system or part of it is out of service, whether planned or accidental. The code requires notification of the authority having jurisdiction and, when needed, a fire watch.

Testing required after a system is modified, repaired, or expanded, to confirm the affected portions still function as designed. The scope depends on the extent of the change.

The manufacturer's listed limits, expressed in percent obscuration per foot, within which a smoke detector must respond. Field testing verifies the detector remains inside that range.