ME Fire Alarm key terms

A power-limited or non-power-limited circuit whose wiring is controlled by Article 725 rules for remote-control and signaling, operating at voltages and currents above Class 2 or 3 thresholds and requiring Chapter 3 wiring methods.

A circuit supplied from a listed Class 2 power source and limited in voltage and energy so that fire initiation risk is low; Article 725 permits reduced wiring methods and often Article 800-style cable.

A circuit supplied from a listed Class 3 power source, limited in voltage but carrying higher current or energy than Class 2, so Article 725 requires more restrictive cable and installation rules.

Power-limited fire alarm circuit: a fire alarm circuit supplied by a listed power-limited source and installed under Article 760 Part III, allowing Class 2 or 3 cable methods rather than Chapter 3 raceway methods.

Non-power-limited fire alarm circuit: a fire alarm circuit that is not power-limited, installed under Article 760 Part II and requiring Chapter 3 wiring methods such as raceway or metal-clad cable.

Circuit wiring covered by NEC Article 800 for telephone, data, and similar signal transmission, including entrance, riser, and horizontal cabling; its separation and listing rules affect fire alarm pathways sharing those spaces.

The ability of a fire alarm circuit to continue operating during fire exposure, achieved through listed circuit integrity cable, raceway with fire-resistive protection, or other approved means for survivability.

An NFPA 72 signaling line or initiating device circuit that leaves the control unit and returns on a separate path, so a single open or ground fault does not prevent alarm signal transmission.

A circuit in which the devices connect in a single path that terminates at the last device; an open fault beyond that point disables all devices downstream of the break.

A signaling line circuit with Class A redundancy plus isolation of each device or group, so a short circuit on one segment does not disable communication with the remaining devices.

The wiring path connecting automatic detectors and manual stations to the fire alarm control unit, also called an initiating loop or zone circuit, classified as Class A or Class B.

A detector, module, or station with a unique digital address that reports its individual identity and status to the control unit, allowing precise annunciation of the alarm location.

A grouping of initiating devices wired to a single circuit that annunciates as one area or zone rather than as individual devices, typically used with non-addressable control panels.

A detector that samples smoke at a single location using photoelectric light-scattering or ionization sensing, mounted on a ceiling or wall per NFPA 72 spacing and location rules.

The maximum coverage area and distance between smoke or heat detectors, set by NFPA 72 using the listed spacing, ceiling height, and construction adjustments such as beam pockets and slopes.

A smoke detector installed in an air-handling duct to sense smoke in the airstream and initiate shutdown of the fan or other smoke-control action, with its sampling tubes oriented to airflow.

A device such as a horn, strobe, chime, or speaker that produces audible, visible, or voice evacuation signals to occupants, governed by NFPA 72 audibility, intelligibility, and candela requirements.

The luminous intensity of a visible notification appliance, used to select strobes so that required illumination levels are met across the protected area per NFPA 72 tables.

The coordinated flashing of visible appliances in the same field of view so that strobes flash together, required by NFPA 72 to prevent seizures and reduce confusion during evacuation.

The power and signal path from the control unit or power supply to notification appliances, sized for voltage drop so appliances receive their rated operating voltage at the end of the circuit.

The loss of voltage along a circuit due to conductor resistance; NFPA 72 requires notification appliance circuits to be designed so the last appliance still operates within its listed voltage range.

A facility that receives and processes signals from protected premises fire alarm systems, categorized as central station, proprietary, remote, or auxiliary with distinct NFPA 72 requirements.

A listed supervising station, typically UL 827, staffed continuously and equipped to monitor alarm, supervisory, and trouble signals from many protected premises and dispatch response.

A constantly attended location, such as a fire department, that receives signals from a protected premises over a communications path and is not a central station or proprietary station.

A protected premises system that connects to a municipal fire alarm circuit, using a listed trip device or shunt so the public box transmits the alarm to the fire department.

The building or area covered by a fire alarm system, whose detection, notification, and control equipment are installed and monitored as one coordinated unit.

The recurring NFPA 72 program of visual inspection, functional testing, and maintenance of initiating devices, notification appliances, and control equipment at frequencies set by the code tables.

The NFPA 72 form documenting the installed system configuration, device locations, and as-built details, signed by the installer and used as the baseline for later inspections.

The maximum interval, such as monthly, quarterly, semiannual, or annual, at which each device type or system function must be tested under NFPA 72 Table 14.4.3.2.

The continuous and unobstructed path from any point in a building to a public way, comprising exit access, the exit, and exit discharge under NFPA 101.

The total number of persons that may occupy a space, calculated from NFPA 101 area factors or fixed seating, used to size egress width and determine exit requirements.

The NFPA 101 grouping of a building or space by use, such as assembly, business, educational, or residential, which determines the required detection, alarm, and egress features.

The portion of the means of egress that leads from an occupied space to an exit, including aisles, corridors, and intervening rooms, and limited in travel distance by NFPA 101.

The measured length along the path of egress travel from the most remote point in a space to an exit, capped by NFPA 101 based on occupancy and sprinkler protection.

The Maine credential issued under state fire alarm statutes and rules authorizing a business to design, install, service, or maintain fire alarm systems within the state.

The state regulations adopted under Maine fire alarm statutes that set licensing, installation, inspection, and reporting requirements in addition to referenced NFPA standards.

The formal examination of submitted fire alarm drawings and calculations by the authority having jurisdiction before installation, confirming code compliance and completeness.

A single-line schematic showing fire alarm circuits, control equipment, power supplies, and device connections, used to understand system architecture and verify wiring class.

The NFPA 72 computation of secondary power capacity using standby load times required standby duration plus alarm load times alarm duration, with a derating factor applied.