Understand the basics of Fire Alarm system

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What is the Fire Alarm System

A Fire Alarm Systems is for life safety of the public. The system gives audible and or visible warning of a fire in the Building.

It is indicating a fire incident that requires emergency actions such as fire-fighting, emergency services and evacuation from a building.

Once the system identifies the fire with the help of various detectors installed across Building.

It gives the alarm to the occupants of a building of fire through sounders and flashers and calls the fire-fighters through automatic communication.

The components of Fire Alarm are designed and installed as per NFPA 72. 

Fire Alarm system uses manually operated devices like pull stations or automatically activated devices like smoke and heat detectors.

Basic Design of Fire Alarm System

Important Components of Fire Alarm System

Smoke/heat detector, Duct detector, Beam detector, Manual pull station, Interface unit, Strobe, Sounder and Sounder/strobe

Fire Alarm System Integration

The Fire Alarm System is integrated with all the system in buildings, below listed system were integrated with Fire Alarm

1. HVAC
   1. AHU
   2. FCU
   3. VAV
   4. VRV
   5. MSFD
2. Mechanical
   1. Fire Pump
   2. Electrical Pump
   3. Jockey Pump
   4. Fuel Tank
3. Electrical
   1. Generator
   2. FM200
   3. FOAM System
4. ELV System
   1. Public Address
   2. Access Control
   3. BMS
   4. Lighting Control
   5. Central Battery

Basic Working Principle of Fire Alarm System

Fire Alarm system mainly complies with NFPA72 code. Now we’ll see the working of the Fire Alarm system in particular Building. 

Let’s take an example of a familiar place we all visit, i.e. Mall.

If the fire initiated inside the Mall, the smoke detector senses the smoke and indicates Fire Alarm Control Panel (FACP), 

Fire Alarm Control Panel(FACP) programmed as per the individual building requirements with local civil defence codes and standards. Currently, we will see an example of the Mall. 

Here when the detector and indication sense smoke has occurred in FACP, the system specialist along with security is given three minutes to investigate whether it is the real fire or just dust that detector has sensed.

If it’s only dust, then system specialist along with security, acknowledges the FACP and silences the alarm Whereas no further fire signal will be initiated in Building.

If it is real fire then after 3 minutes, FACP automatically gives a signal to sounder/flasher and public address in building to give evacuation message and sound an emergency alarm in Building. 

So people in Mall can evacuate the BuildingBuilding immediately, which is the first step FACP initiates, below we are going to see the sequence.

FACP sends the signal to Access Control system to unlock all Entrance Access doors and fire exit doors and other room where general public and staff are inside Mall.

FACP sends a signal to the HVAC system to shutdown AHU, FCU, VRV, MSFD to stop the airflow, which prevents the smoke from spreading around the Mall.

FACP sends a signal to the Lighting control system/central battery system to make sure all lights are ON in the Mall for the public to ensure the route is clear to exit. 

FACP sends a signal to BMS to monitor all systems functioning properly during the fire if any system fails then system specialist along with security manually take the necessary action to prevent the fire from spreading and public to exit safely.

Hence Fire Alarm System is installed in Building for public safety. Therefore Fire Alarm System is called as one of Life Safety System.

Have a question about this topic? Message Hamza on WhatsApp and get a reply from the author.