How Do Fire Alarms Help?
- Life safety solution
- Provides an opportunity to avoid spread of fire
- Helps restrict losses due to fire
- Gives valuable information during evacuations
A Fire alarm system is designed to detect the early signs of fire by processing the inputs from the field devices, to notify the occupants to evacuate the premises using audio visual triggers & to call for help from emergency services when it has determined that an alarm condition is warranted.
Conventional fire alarm systems are capable of indicating the Zone or Area while addressable fire alarm systems can indicate the exact Location or Detector from where the Fire is detected. The central monitoring stations are notified about the emergency using auto dialers, which use standard communication means such as telephone line or GSM technology.
The alarm receiver at the central monitoring station is an automated device that informs the operators about all pertinent site information such as the alarm trigger device, date & time of alarm, etc. so that they are able to relay as much detail as possible to the authorities. The central station operator determines what action should be taken upon receipt of a signal.
Another emerging technology is monitoring the system over the Internet. Some Fire Alarm Systems utilize Emergency Voice Alarm Communication Systems (EVACS) over public address systems to provide pre-recorded & manual voice messaging to building occupants.Building Safety Interfaces are integrated in large establishments to allow the fire alarm system to control the spread of fire & smoke by influencing air movement, controlling sprinkler pressure or flow switches, electrical systems, human transport management for exit routing & thus prepare the building for evacuation.
Central part of the system, co-ordinates the signals & resultant actions of the system, monitors & displays the healthiness of system in normal operation & location information in case of fire.
Being Life safety systems control panels are generally equipped with sealed, lead-acid backup batteries for providing secondary power in case of failure of the primary main power supply.
When the Main Control Panel receives a signal from any of the detectors or manual call points, it triggers these devices to provide stimuli for initiating emergency action & informing users, emergency response personnel & occupants about the same. Examples are Flashing light, strobe light, siren, bell, electromechanical horn, speaker, text display or a combination of these devices.
No matter what the size of the establishment, the control panel is always in one corner of the premises. Remote annunciators are usually an alpha-numeric display (may be graphic) that indicates where in the building the alarm originated by taking information from the control panel. It may also indicate the type of device. Placed at strategic locations throughout the premises, remote annunciators are used by emergency personnel for locating the fire quickly. Sometimes these will contain some control functions such as alarm silence & alarm reset.Must be key or keypad controlled.
One is not better at detecting a fire than the other, they just utilize different technologies. Addressable systems enable each & every initiating device to have an individual address or zone identifier. The operator comes to know exactly which device triggered the alarm and it also indicates exactly which detector is faulty, thus simplifying service. Another added advantage of an addressable fire alarm system is that large number of different devices can be connected to a loop that runs through the premises. It stands to reason that addressable systems have a higher equipment cost but in return give several advantages over a conventional system.
Field devices in a conventional fire alarm system are basically divided in small groups, called zones that are hardwired to the control panel. The problem is that there may be a dozen detectors on a single zone & in case one is faulty, the operator cannot know the exact location of fire and the technician is tasked with finding which detector actually triggered the alarm. More cable is required because there is a limitation on the number of devices that can be connected to each zone. A small facility or one with a limited number of devices may do very well with a conventional system.
There arehybrid systems as well, that mix conventional hardwired zones with addressable loops on the same control panel. They fit certain applications better than just one technology would.