Fire Alarm System Supervision Flashcards

Fire Alarm Control Systems

• Supervision involves monitoring the fire alarm system to identify malfunctions and ensure timely repairs.
• The Fire Alarm Control Panel (FACP) tests the continuity of the wiring loop, serving as a continuity tester.

Wiring Types and Functions

• Splices and junctions do not affect the supervision process if electrical continuity is maintained through the wiring loop.
• T-taps create dead ends in wiring, leading to unmonitored connections which can prevent fault detection.
• Class A wiring incorporates redundant paths to ensure the system remains functional during faults, unlike Class B wiring, which is a single path without redundancy.

Circuit Operations

• Class A circuits transition to two unsupervised Class B loops if a connection breaks, allowing continued fire detection.
• The FACP has multiple circuit functions including connections to initiating devices, output notifications, relays, and auxiliary powers.

Safety Mechanisms

• Short circuits create low resistance connections that can damage power sources; supervision circuits minimize this risk.
• Diodes permit current flow in one direction, functioning like check valves to control power in fire alarm systems.

Device Management

• Initiating Device Circuits (IDC) provide signals from detectors to the FACP and power smoke detectors, with changing current indicating alarms.
• Notification Appliance Circuits (NAC) serve as the system's alert mechanism, powering horns and strobes to notify occupants.

Detection and Alarms

• Status relays in the FACP indicate system conditions—alarming status, supervisory alerts, or trouble notifications.
• Resetting devices like smoke detectors involves temporarily shutting off power to reset circuits and clear alarms.

Voltage Dynamics

• Conflicting voltages during supervision ensure horns and strobes remain inactive unless an alarm is triggered, using reverse voltage polarity.
• Polarized devices have diodes that permit current flow only when in an alarm state, blocking during supervision to avoid false alerts.

Fault Detection

• Open circuits occur when wiring is broken, resulting in increased voltage; short circuits drop voltage significantly, potentially crippling the alarm system.
• Backup battery systems ensure fire alarm functionality continues even when utility power fails.

Specialized Components

• Annunciator loops manage data transfer to remote panels, powered by the FACP's auxiliary supply.
• Blocking capacitors in fire alarm speakers allow audio to pass while preventing constant DC supervision current from interfering with operation.

Summary of Circuit Management

• Relay operations in the panel switch between continuity checks and audio signal supply depending on the system's power source during alarms, facilitating effective communication during emergencies.