Fire Alarm Systems can be broken down into four main types;
1. Conventional Fire Alarm Systems
In a Conventional Fire Alarm System, physical cabling is used to interconnect several call points and detectors, the signals from which are wired back to the main control unit.
Call points and detectors are arranged in “Zones” to simplify locating the cause of the alarm, this is important for both the fire brigade and general building management.
Each zone is indicated at the Fire Alarm Control Panel either with an indicator lamp, a text display or in some cases both.
It makes sense that the more we can divide a building into zones, the more accurate locating the alarm trigger will be.
The Control Panel is wired to a minimum of two sounder circuits which could contain bells, electronic sounders or other audible fire alarm devices.
It is these devices which sound the alarm when triggered.
2. Addressable Fire Alarm Systems
The detection principle of an Addressable System is the same as a Conventional System except that each detector is given a set Address (usually by means of a dip-switch) and the Control Panel can then determine exactly which detector or call point has initiated the alarm.
The detection circuit is wired as a loop and up to 99 devices may be connected to each loop.
It is common for the loop to be fitted with Loop Isolation Modules so that the loop is sectioned in order to ensure that a short circuit or single fault will only cause the loss of a small part of the system; allowing the rest of the system to function normally.
In the previous two systems, the “Conventional Fire Alarm System” and the “Addressable Fire Alarm System” the detectors are not considered “intelligent” as they can only give output signals representing the value of detected phenomena.
It is left up to the Control Unit to decide whether there is a fire, fault, pre-alarm or other.
3. Intelligent Fire Alarm Systems
However, in our next type of System, which is an Intelligent Fire Alarm system, each detector effectively incorporates its own computer which evaluates the environment around it and communicates to the Control Panel whether there is a fire, fault or the detector head needs cleaning.
Essentially Intelligent Systems are far more complex and incorporate far more facilities than Conventional or Addressable Systems. Their primary purpose is to help prevent the occurrence of false alarms.
Intelligent Fire Alarm Systems are available in 2, 4, and 8 loop versions which means large premises can be monitored from one single panel.
4. Wireless Fire Alarm Systems
The final type of system we will consider is the Wireless Fire Alarm System.
These are an effective alternative to traditional wired fire alarm systems for all applications. They utilize secure, license-free radio communications to interconnect the sensors and devices with the controllers.
It is a simple concept, which provides many unique benefits and is a full intelligent fire detection system without the need for cabling.
In this article, we have learned that Fire Alarm systems are fitted in many buildings we encounter every day and that they are used to warn people within the building of an emergency fire-related situation.
Fire alarm systems are very common in constructions such as offices, houses, factories,… Fire alarm systems are designed to alert us to an emergency so that we can take action. To protect yourself and those around you.
For the fire alarm system to work, fire detection devices are required. See more articles about Types of Fire Detectors here.
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