Fire Alarm Systems: The Basics
Fire alarm systems are required to meet the standards set by NFPA 72, the National Fire Alarm Code. The following explanations are simplified and generalize some technical details, devices, and system components for clarity.
Initiating devices activate the alarm system.
- Manual Pull Station: This device is commonly found on the wall with a label like “Pull in case of fire”. When the handle is moved, it triggers the alarm system.
- Smoke Detectors: When a smoke detector senses smoke, it triggers the alarm system.
- Heat Detectors: When a heat detector senses a rise in temperature above a set point, it triggers the alarm system.
- Sprinkler System Flow Switches: A flow switch is installed in the piping of the fire sprinkler system. When the sprinkler system activates, the flow switch triggers the alarm system.
Notification devices alert people about a fire or emergency.
- Horn: A loud noise maker that alerts people of a fire emergency.
- Strobe: A flashing light emitting device used for visual alert.
- Horn-Strobe: A combination of the horn and strobe in one appliance.
- Speaker: A recorded announcement used for audio alert in some occupancies.
Control and Transmission Devices
Control and transmission devices manage the fire alarm system.
- Fire Alarm Control Panel (FACP): The FACP connects all initiating and notification devices. When an initiating device is triggered, the FACP activates all notification devices. The FACP also sends signals to shut off equipment when necessary.
- Automatic Dialing Devices: The auto-dialer device is a phone/modem that calls a monitoring service to notify the fire department when an alarm is triggered.
- Fire Alarm Annunciator Panels (FAAP): The FAAP is a secondary control panel that can be located in strategic locations. It is a smaller version of the control panel from the FACP.