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What is a fire alarm system?
A fire alarm system is a building system designed to detect a fire, alert the people inside and alert the emergency services. It works around the clock, so a fire is noticed and people start to leave before it spreads.
In larger buildings the same system can also start other safety actions, such as voice evacuation messages over the public address system.
What are the main parts of a fire alarm system?
Every fire alarm system has a control panel, devices that detect a fire, devices that warn people, and a power supply. The panel is the hub of the system: it watches every input and switches on every warning.
Drawing of a fire alarm system. The control panel and its power supply with battery backup are in the fire control room. One loop of two wires leaves the panel and comes back to it. On the way out it carries photoelectric and ionisation smoke detectors, a heat detector for the kitchen and manual call points; on the way back, four modules: a monitor module that reads the sprinkler flow switch, a control module that drives the hooters and strobes, a relay module that closes the AC dampers and controls the pressurisation system, and a relay module that starts voice evacuation over the public address system.
- Fire alarm control panelReceives signals, shows where the alarm came from and sounds the warnings.
- Smoke detectorSenses smoke in the room it covers; photoelectric or ionisation.
- Heat detectorSenses a rise in heat, for rooms where a smoke detector would not suit, such as kitchens.
- Manual call pointThe break-glass unit people press when they see a fire.
- Hooter or sounderThe sound that tells people to leave.
- StrobeThe flashing light that warns people who cannot hear the alarm.
- Monitor moduleReceives a signal from other equipment, such as the flow switch when a sprinkler operates, and passes it to the panel.
- Control moduleReceives the signal from the fire alarm circuit and operates the hooters and strobes.
- Relay moduleAfter the signal from the panel, closes the dampers in the AC ducts and controls the pressurisation system.
- Power supply with battery backupMains power, with backup batteries that take over during a power failure.
What types of fire alarm systems are there?
The two main types are conventional and addressable. A conventional system groups detectors into zones and shows the alarm by zone at the panel, while an addressable system gives each detector its own address, so the panel can tell exactly which detector or call point raised the alarm.
A third option, the wireless system, uses secure radio links instead of cabling between the devices and the panel.
Conventional or addressable: which does a building need?
It depends on both the size of the building and what it is used for. Small, simple buildings are usually well served by a conventional system, while large buildings and high-risk ones need an addressable system.
A floor plan of one hotel floor with 24 rooms in three zones. With a conventional system, a fire in one room lights its whole zone and staff must search 8 rooms; with an addressable system, only that room's detector raises the alarm and staff go to 1 room.
Tap a room to place the fire.
| Conventional | Addressable | |
|---|---|---|
| How the panel shows an alarm | By zone (an area of the building) | By the exact device |
| Usually suits | Small offices, shops, small apartment blocks with a few zones | Hospitals, hotels, high-rise towers, campuses |
| Finding the fire or fault | Search the whole zone | Go straight to the device |
| Linking to other systems | Basic | Detailed, device by device |
In a hospital or a hotel, staff need to reach the right room quickly, and an addressable panel tells them exactly where to go. In a small shop with a few zones, a conventional system does the job simply.
How does a fire alarm system work?
A detector senses smoke or heat, or someone presses a manual call point, and the device sends a signal to the control panel. The panel then sounds the hooters and strobes, shows where the alarm came from, and starts any linked actions the building has.
The signal path: a manual call point and a smoke detector are wired to the control panel, which then, through its modules, sounds the hooters and strobes, starts voice evacuation over the public address system (PA-09), and closes the AC dampers and controls the pressurisation system.
Press the call point or the smoke detector to send a test alarm.
Linked actions can include voice evacuation over the public address system and closing the AC dampers and controlling the pressurisation system, depending on what was designed for the building.
Where is a fire alarm system required?
Whether a building needs a fire alarm system depends on its use, height and size, under the National Building Code of India and the state's building and fire rules. In Kerala, those are the Kerala Municipality Building Rules (KMBR), the Kerala Panchayat Building Rules (KPBR) and the Kerala Fire and Rescue Services rules.
The fire alarm is checked as part of the fire NOC, so it has to be installed to the approved drawings. The whole process, step by step: How to get a fire NOC for a building in Kerala.
Who should install a fire alarm system?
A fire protection contractor should design, install, test and commission the system, so it matches the drawings the fire authority approved. The same contractor can then carry the fire NOC through and maintain the system afterwards.
Automation Asia Associates installs conventional and addressable fire alarm systems as one of thirteen fire protection systems on one contract, to the NBC and local fire rules. Not sure what your building needs? Book the free 15-minute compliance check.
How is a fire alarm system tested and maintained?
Detectors, manual call points, hooters and the panel's batteries are tested regularly, and every test is recorded. Working systems and complete records are what the fire NOC renewal inspection looks for.
Our annual maintenance contract (AMC) keeps the system tested and its records ready for each renewal, which must be done before the NOC expires.
From automationasia.in/articles/fire-alarm-system · Last checked 26 October 2026