4.0 DIFFERENT TYPES OF FIRE ALARM SYSTEMS
Fire Alarm Systems can be broken down into four main types;
4.1 Conventional Fire Alarm Systems: At Basscomm Nigeria, 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. The Types of Conventional Fire Alarm Panels are:
- Nano zone fire alarm panel ( can take only 1 zone/ detector)
- 2 zone fire alarm panel ( can take maximum of 2 zones and each zone takes not more than 100 detectors)
- 4, 6 etc
4.2 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. The Types of Addressable Fire Alarm Panels are:
- Nano loop alarm panel ( this type of panel has only 1 loop card slot)
- 2 loop alarm panel ( this type of panel comes with 2 card slots and each card can take 100 detectors connected to each card)
- 4, 6 loop panels
Each addressable panel comes with 1 loop card, so when purchasing a panel buying of extra cards is considered; the number of detectors determines the type of panel to recommend.
4.3 Intelligent Fire Alarm Systems: 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 mean large premises can be monitored from one single panel.
4.4 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.
5.0 ADVANTAGES OF ADDRESSABLE OVER CONVENTIONAL
- Reduced installation cost
- Flexible wiring topology
- Better false alarm management
- Early detection. Reduced damage to property
- Pin point location of the fire
- Increased flexibility
- Ease of use
- More effective maintenance
- Increased reliability
- Remote control with graphic maps (via IP)
6.0 DISADVANTAGE OF AN ADDRESSABLE FIRE ALARM SYSTEM
The main disadvantage of installing an addressable fire alarm system is that the systems are more expensive than conventional fire alarm systems. However, the level of protection that they offer makes them worth the price difference.