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How Do Fire Alarm Systems Work?

Last Updated: March 9, 2022

Your fire alarm system is one of the most important life safety systems in the building. Most people have experienced a fire alarm in action as part of an evacuation practice or false alarm. Of course, the real purpose of a fire alarm is to alert people of an emergency when an actual fire is present. This often requires complex design and engineering to accomplish. But no matter how fire alarm setups vary between buildings and industries, their primary purpose remains the same.

Here’s a look at the basic functions these crucial systems so you can better understand how fire alarm systems work.

Fire Detection

The first step in any fire alarm system is to detect heat and smoke that indicate the presence of flames. Fire detection is made possible by initiating devices, which include:

  • Smoke and heat detectors: Most people are familiar with these devices because they’re installed in homes and apartment buildings. However, smoke detectors come in many varieties, including photoelectric smoke detectors, ionization smoke detectors, and in-duct smoke detectors. In places where smoke detection is unreliable, heat sensors may be installed instead.
  • Sprinkler water flow switches: These devices detect movement in the sprinkler system when a sprinkler head activates, transmitting a signal to the fire alarm control panel and setting off the alarm in the process.
  • Manual pull stations: When a building occupant spots a fire faster than detection devices can sense it, he or she can activate a manual pull station and set off the alarm.

Building Occupant Notification

Detecting a fire is one thing—letting everyone in the building know about it is another. Occupant notification is facilitated by audio and visual indicating appliances that go off when the system enters the alarm state. These include:

  • Horns, bells, or chimes: The blaring noise of an audio notification appliance captures everyone’s attention immediately and makes it obvious that it’s time to evacuate the building.
  • Spoken announcement: It’s possible to configure your intercom and paging system to broadcast a pre-recorded message instructing building occupants what to do if there’s a fire. You can also deliver live instructions by speaking into a built-in microphone.
  • Strobe lights: For the hearing impaired, strobe lights provide a visual indicator that an emergency is underway.
  • Electronic signs: As the visual equivalent of making a PA announcement, electronic signage can be programmed to read “EMERGENCY” and deliver concise instructions for mitigating the threat and evacuating to safety right away.

Fire Department Notification

Not all fire alarms provide automatic notification to the fire department—only monitored systems have this capability. With fire alarm monitoring, a signal is automatically transmitted to the local fire department when an initiating device activates the building notification system. This eliminates the need to make the call manually, ensuring that help is dispatched to your location as fast as possible. Monitoring also automatically notifies the fire department if the building is empty when a fire ignites, potentially preventing catastrophic property damage.

Programming and Operation

The control panel is the heart of any fire alarm system. It allows users to program and operate the system from a central location. It also displays the current state of the system and any troubleshooting information as needed. From the control panel, you can silence an alarm, reset the system following an incident, and reprogram settings if necessary.

Other system operations occur automatically. For instance:

  • The activation of an in-duct smoke detector may automatically shut down the heating and cooling equipment.
  • A set-off smoke detector in the lobby may automatically call the elevators to a designated floor of the building.
  • Activated smoke detectors in select areas may automatically turn on exhaust fans.

Primary and Secondary Power Functions

Similar to exit and emergency lighting, fire alarms should have backup batteries in case the central power goes out. With the correct design and implementation, the fire alarm batteries should take over when needed with no interruption in fire protection. The batteries can be self-contained or enclosed within the control panel. A charger is also required to keep the batteries ready at all times.

Schedule Fire Alarm Services in the Mid-South

If you are looking to construct a new building in Tennessee, Arkansas, Mississippi, or Alabama and you need to install a code-compliant fire alarm system, give us a call.  If you already have a functioning fire alarm, but you need an inspection to ensure everything is working properly or if you’re dealing with repeat false alarms that disrupt business operations, and you need an emergency repair to restore normal function, we can help!

We offer fire alarm installation, inspection, testing, maintenance, and repair for business owners and property managers throughout our service area and would love to serve you.

For questions about our services, or to schedule an appointment, please contact us online or call us today at 901-531-6550.

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