MI Fire Alarm key terms

A component that starts a signal in the fire alarm system when it detects a change such as smoke, heat, water flow, or manual pull. It is the first link in the detection chain.

A device that alerts occupants through audible, visible, or tactile output, such as horns, strobes, speakers, or bed shakers. It responds to signals from the control unit.

The central panel that monitors initiating circuits, processes signals, and operates notification and auxiliary circuits. It supplies power, makes system decisions, and displays status information.

A field device with a unique digital identifier that reports its individual status to the control unit. Addressable devices allow precise identification of the device in alarm or trouble.

A grouping of initiating devices wired on a common circuit, where the control unit indicates only the zone rather than the individual device. Troubleshooting requires walking the circuit.

A resistor installed at the far end of a conventional initiating or notification circuit that allows the panel to monitor wiring integrity. Opens or shorts change the supervised current.

Continuous monitoring of circuit wiring and component integrity so that a fault produces a trouble signal rather than going unnoticed. Supervision covers opens, shorts, and ground faults.

An indication that a system component or circuit is not functioning properly, such as an open circuit, ground fault, or power loss. It is distinct from an alarm and typically sounds a distinctive tone.

The output indicating that a fire condition has been detected and that notification appliances should activate. It takes priority over supervisory and trouble signals on the same system.

A control-unit function that stops the audible and visible output of notification appliances while preserving the alarm condition and display. A subsequent alarm typically reactivates the notification circuits.

A control-unit action that clears alarm or trouble conditions and returns the system to normal supervisory operation after the initiating condition has cleared. Devices may require manual reset afterward.

A device that senses products of combustion and sends an alarm signal. Common types include ionization, photoelectric, and air-sampling units, each suited to different fire signatures.

A smoke detector mounted on or in an air-handling duct to sample airflow and detect smoke moving through the HVAC system. It typically triggers shutdown of the air handler.

A device on a sprinkler system that detects sustained water movement in the piping and sends an alarm. It is typically set with a delay to avoid false alarms from pressure surges.

A device that monitors the position of a valve or the condition of a component and reports abnormal status. It produces a supervisory signal rather than a fire alarm.

An indication that a system or suppression component is off-normal, such as a closed valve or low pressure, without indicating a fire. It warns of conditions that could impair protection.

A notification device that produces sound to warn occupants, such as a horn, bell, or speaker. Its output must be distinguishable from other building sounds and meet audibility requirements.

A notification device that produces flashing light to warn occupants, especially those with hearing loss or in high-noise areas. Flash rate and intensity are governed by code.

The normal source of electrical energy for the fire alarm system, usually a dedicated branch circuit. It must be reliable and arranged so that it cannot be accidentally disconnected.

A backup energy source, such as batteries or a generator, that keeps the fire alarm system operating when primary power fails. It must support the system for a defined duration.

An unintended connection between a circuit conductor and ground that can disrupt operation or cause false signals. Supervised systems typically report it as a trouble condition.

A break in a conductor path that stops current from flowing, often caused by loose terminations or damaged wiring. On supervised circuits it produces a trouble signal.

The National Fire Alarm and Signaling Code, which sets requirements for design, installation, testing, inspection, and maintenance of fire detection and signaling systems. It is widely adopted as the governing standard.

The National Electrical Code, which governs electrical wiring methods, overcurrent protection, and grounding for fire alarm circuits among other installations. Article 760 addresses fire alarm systems specifically.

The organization or official responsible for approving installations and enforcing code requirements, such as a fire marshal or building official. Their interpretation can govern acceptance of a system.

A documented test performed after installation to verify that the system operates as designed and meets code before it is placed in service. Results are recorded and made available to the authority.

The process of examining submitted design drawings and specifications against code and project requirements before installation begins. It catches deficiencies while changes are still inexpensive.

Record drawings updated to show the system as actually installed, including device locations and circuit routing. They support future inspection, testing, and maintenance work.

A document certifying that the fire alarm system was installed and tested in accordance with applicable codes and approved plans. It captures system details and is provided to the owner.

The property of alarm sound being loud enough to be heard and recognized above ambient noise throughout the protected area. Code sets minimum sound pressure levels above background.

An electrical circuit supplying only the fire alarm system, with no other loads connected. It improves reliability and prevents unrelated equipment from interrupting alarm power.

A device such as a fuse or circuit breaker that interrupts current when it exceeds a safe level, protecting conductors and equipment. Fire alarm circuits are protected in accordance with code.

The amount of energy a standby battery can deliver, usually expressed in ampere-hours, which determines how long the system can operate without primary power. It must be sized for standby plus alarm load.

The reduction in voltage along a circuit caused by conductor resistance and current flow. Excessive drop can prevent notification appliances from operating at their rated output.

A circuit arranged so that an open or ground fault does not prevent operation of devices beyond the fault. It provides continued operation and reports the fault as a trouble.

A circuit where an open or ground fault disables all devices beyond the fault point. It is supervised but does not provide continued operation past a break.

A visual and functional check of system components to confirm they are present, accessible, undamaged, and in the intended condition. It is often performed at defined intervals under a maintenance program.

The operation of system components to verify that they perform their intended function, such as activating a detector or appliance. Test results are recorded and compared with code intervals.

Work performed to keep the fire alarm system in proper operating condition, including cleaning, adjustment, repair, and replacement of components. It follows inspection and testing findings.

A check that a smoke detector responds within its listed sensitivity range, often using a calibrated instrument or aerosol. Out-of-range units are cleaned, adjusted, or replaced.

A condition in which a fire protection system or portion of it is out of service, reducing protection. It requires notification of the authority and occupants and may require a fire watch.