Components of fire alarm system
When a fire alarm system is mentioned, most people think of the alarm box on the wall with a pull-string that hangs down. This is only one component of a fire alarm system. A fire alarm system is a network of devices and systems used to detect and report fires, or other emergencies, to the occupants of a building and/or emergency services personnel.
These fire alarm systems are commonly divided into two categories:
- Manual fire alarm systems
- Automatic fire alarm systems
Manual fire alarm systems are activated by the occupant of a building. This can be done by pulling a manual pull station, which will then activate the horn or speaker in the area and notify the occupants that there is an emergency. This would be the most common type of fire alarm system in a small storefront setting.
Automatic fire alarm systems are activated when smoke is detected or if heat sensors detect that there is extremely high temperatures in certain areas, such as near the ceiling. These types of systems will sound an audible horn and strobe light (if installed) until deactivated by an authorized person (or will deactivate automatically after a period of time if no one is found in the building).
There are several components that make up most fire alarm systems. These include:
- Smoke detectors
Smoke detectors are probably the most important part of a fire alarm system. They are installed in areas where a fire is most likely to start, such as in the kitchen, near the furnace, or in a closet. Smoke detectors are either photoelectric or ionization. Photoelectric smoke detectors use a light sensor to detect smoke particles. Ionization smoke detectors use a radioactive source of ionization to detect the smoke particles.
2.Heat detectors
Heat detectors are used to detect high levels of heat, which may be an indication of a fire. They are commonly installed in the ceiling near the exhaust fans for kitchens and bathrooms.
- Pull stations
Pull stations are used to manually activate a fire alarm system. There is usually one pull station per floor in a building.
- Control panel
The control panel is the brains of the fire alarm system. It is where all the wiring is connected and all the settings are made.
- Alarm box
The alarm box is what most people think of when they hear the term “fire alarm.” It is a metal box that is mounted on the wall and has a pull-string that hangs down. When the alarm is pulled, it sends a signal to the control panel to activate the fire alarm system.
- Duct detectors
Duct detectors are installed in the air ducts of a building and are used to detect smoke particles.
- Beam detectors
Beam detectors are used to detect the presence of a flame. They are most commonly used in areas where a fire is likely to start, such as in a warehouse or garage.
- Strobes, horns, speakers
Strobes, horns and speakers are used to notify the occupants of the building that there is an emergency.
- Tamper switches
These switches are set to activate the alarm if tampered with. Usually they will only allow authorized service personnel (such as a fireman) to disable it. This is also commonly seen amongst large office buildings, where special key cards are needed to be scanned before being allowed into the building after hours, which will then automatically disable the alarm system.
- Auxiliary power supply (Optional)
This is an optional part of the fire alarm system that allows the control panel to remain powered in case of a power outage. This will ensure alarms can still be sounded even if there is no electricity or generators are not working. A battery backup often backs up the auxiliary power supply and protects the control panel from surges.
A standard fire alarm system should include all of these components, however like with any large project, there are always small alterations to be made. For example, some buildings may not have duct detectors if they don’t need them. Certain offices might not have speakers installed in case people are working late at night or early in the morning when no one else is in the building. Often times, strobes are also not installed, since they can cause problems for people with light sensitivities or epilepsy disorders.