How the Fire Alarm System Works

Have you ever wondered how buildings in Singapore prepare for emergencies such as fires? The secret to an excellent fire protection setup is the use of a sophisticated fire alarm system made up of equally important interconnected parts.

Let’s look at how modern alarm systems function to use its potentials to the fullest.

Detection and Notification
To better understand how fire alarm works, one needs to differentiate between two important functions: initiating devices and the notification devices.

Detection of the fire is important in sending timely warnings to the occupants and authorities to prevent injuries, minimize damage, and to control the fire. An example of a detection device is a fire detector which looks for signals of live flame within the area. A heat sensor on the other hand may be able to detect changes in temperature and the presence of smoke, while the water flow detector is attached in a sprinkler to monitor changes in the temperature. An older alarm system uses a thermal detector which is easier to maintain and more affordable than the smoke detector, but they can be unreliable if not placed in strategical spots. The smoke sensor either has an optical detector or an ionization detector. All those mentioned are automatic detectors and are programmed to send signals to the control panel if there is an anomaly. Manual initiation may be done in case of other emergencies by pulling a handle to activate alarms.

Notification devices may consist of the emergency alarm or horns, flashing lights, and a voice communication system that will alert the occupants of an ongoing emergency. In some buildings in Singapore, a combination of the three is installed to ensure that there are visual and auditory warnings for the occupants who may have visual or hearing impairment. Once the control panel receives the signal from the detector, the alarm output devices are activated automatically. In a more sophisticated system, the electrical equipment are automatically shut down and the ventilation system is controlled to prevent the spread of fire.

Goal and Functions
The goal of installing a fire alarm system in Singapore is not to stop live fire, but to notify the occupants of a developing emergency as soon as possible as well as to alert authorities who are supposed to respond to the crisis. A fire protection system in one building may be different to another system installed in a high-rise residential complex because the type of occupants, the type of equipment housed in the building, the use of the building, and the number of buildings and units, and the critical contents are all considered when installing the right warning system. From these factors depend the following functions: means of identification of a developing fire, transmission of the alarm to authorities, control of the fire by controlling the environment, and the alert used to notify the occupants.

Fire Suppression and Other Emergencies
A fire alarm does not just work during fires, but they can also be programmed to respond to other emergencies such as severe weather, terrorism, bomb threads, high carbon monoxide levels, and others. A suppressing system is also installed to minimize potential damage while waiting for the authorities to respond to the emergency. Devices such as gaseous fire extinguishing system and sprinklers are used. The gaseous fire extinguishing system is similar to how a regular fire sensor works but they are quite rare.

If a sprinkler system is also installed, it will automatically activate at the same time as the other notification devices. Water is the most ideal fire extinguishing agent in most fires because it is easier to control and cheaper to install. A sprinkler may be classified as a dry, pre-action, wet, and deluge system depending on the equipment and materials present in the building.

Other fire suppression systems are not as effective in controlling other types of fire, that is why you might also find foam fire systems and waterless fire systems. The foam fire system uses a mixture of water, air, and foam concentrate which may be used to both coat and cool fire. On the other hand, the waterless fire system or clean agent fire system uses chemical agents and inert gasses. This may be used for buildings that house a lot of electronic equipment which can be damaged by water from the sprinklers.