LEARN ABOUT AUTOMATIC FIRE ALARM SYSTEM

Automatic fire alarm system is a system that automatically detects a fire or fire risk and notifies the place of fire occurrence to the person who installs the automatic fire alarm system.

1. Structure of automatic fire alarm system

A typical automatic fire alarm system will have 3 components as follows:

Fire fighters center

Designed as a cabinet, including the main equipment: a control mainboard, modules, a transformer, a battery.

Input devices

• Detector: smoke detector, heat detector, gas alarm, fire alarm ...
• Emergency switch (emergency push button).

Output device

• Extra display panel (keyboard).
• Alarm bell, siren.
• Alarm lights, exit lights.
• Phone dialer automatically.

2. Classify automatic fire alarm system

If sorting the automatic fire alarm system according to the working principle of a fire detector:

• Automatic fire alarm system using smoke detector: It is an automatic fire alarm system working based on the working principle of smoke detectors. This system primarily detects an increase in smoke concentration in the protected area.
• Automatic fire alarm system using thermal fire detector: It is an automatic fire alarm system that works based on the working principle of a fire detector. This system primarily detects temperature changes in the protected area.
• Automatic fire alarm system using light detector (fire): Working based on the working principle of fire detectors. This system primarily detects the intensity of light enhancement of the fire in the protected area.
• Automatic fire alarm system using mixed fire detector: It is a working system based on the working principle of mixed fire detectors such as heat and smoke detectors; fire and heat detectors. This system primarily detects changes in environmental factors in the protected area.
• Classify automatic fire alarm system according to the specification of fire alarm system.
• Automatic fire alarm system by region (automatic fire alarm system usually): is an automatic fire alarm system with a fire alarm function to an area, a place (there may be one or more fire detectors). The protection area of ​​an area can range from a few tens to 2,000 m2 (depending on the area characteristics).
• Automatic fire alarm system by address: An automatic fire alarm system capable of fire alarm accurately to each position of each separate detector (each specific address). The protection area of ​​a fire alarm address is limited to a few tens of square meters (depending on each type of fire detector). Intelligent automatic fire alarm system: With the development of science and technology, automatic fire alarm system has developed into intelligent fire alarm system (Intelligent fire alarm system). This is an automatic fire alarm system in addition to the normal fire alarm function by address, it can also measure some environmental parameters of the area where the fire detector is installed such as temperature, smoke concentration, ... and it is possible to change the threshold of fire detectors according to the design and installation requirements. In practice, this classification is often used.

3. Operation principle of automatic fire alarm system

• When normally the whole system is in live, standby mode. In this mode, the fire alarm center always has programming to check the working to the devices in the system and the fire detectors, modules ... also have a response signal to the center. Periodically, over time (optional) the center will print the status of the system and information on the equipment to be maintained. The circuit always has Io current running through it.
• In monitoring mode if the center receives an error signal from the device or does not receive a response from the device, the center will switch to trouble mode. All information about the incident will be displayed on LCD liquid crystal display.
• When a fire occurs in protected areas, the changing environmental factors (temperature, smoke, light) will affect the fire detectors. When these elements reach the working threshold, the fire detectors will work to generate signals transmitted to the center (including fire signals and signaling signals of fire alarms). At the fire alarm center, there will be signal processing activities carried out according to the program installed to give the signal of the fire area through central speaker and LCD liquid crystal display. At the same time the corresponding peripherals will activate to transmit fire alarm signals and perform the tasks set out.
• In the case of a fire alarm center with additional monitoring functions for other devices, when there is a change in the status of the equipment (eg: fire fighting pump, active flow switch ...) then the system will switch to notify monitoring device to change status. Information about this change will be displayed on the center crystal screen of the center. This mode will also end automatically if the monitoring device returns to its normal position.