A fire alarm is a unit made of several devices, which uses visual and audio signalization to warn people about a possible fire, smoke, or carbon monoxide occurrence in the area of coverage. Fire alarms are usually set in fire alarm systems to provide zonal coverage for residences and commercial buildings. The warning signal is either a loud siren/bell or a flashing light, or it can include both. Some fire alarm systems use additional warnings, such as sending a voice message or making a phone call.
Depending on the functionality and the integrated components, there are several classifications of fire alarm systems.
A conventional fire alarm system consists of the following devices:
Wireless fire alarm systems do not use any wiring between the fire control panel and the other devices. Most fire alarms used today are wireless. The most advanced use smart technology, and can be integrated into a smart home with various software applications.
The fire alarm panel (or the fire alarm control panel - FACP) is the base or the control hub of the system. It controls the settings of the other components and communicates the information through the system.
Fire detectors can be heat, smoke or carbon monoxide sensors. They are placed around the building to trace the presence of such emergencies. Some advanced sensors can even detect radiation. Call points or pulls belong to manually-controlled fire alarm systems. Most residential properties don’t use them, but many business facilities still do. Sounders emit a loud siren signal. Flashers are for visual warnings and emit intermittent or rotating flashes (typically red or white).
A fire alarm system can use the main electricity power supply as a primary source. In case of power failure, the system switches to the secondary power supply, consisting of a fire alarm battery. Conventional fire alarms need frequent battery replacements. Some of them require basic technical skills, such as using a screwdriver to mount their parts on a wall or ceiling.
Contemporary fire alarm systems use automatic functions to detect the occurrence of an event that may result in a fire. They receive a signal from a fire sensor (smoke, heat or carbon monoxide detector) and automatically transmit it to the fire alarm panel.
In wireless systems, the signal from the detectors to the control panel is transmitted with radio frequency. Heat detectors usually have built-in thermistors to sense the heat. Carbon monoxide detectors use integrated chemical, electrochemical, opto-chemical or biomimetic cells to trace the gas. Smoke detectors use photoelectricity or ionization to detect smoke or combustion particles. Combined detectors use a number of detection mechanisms.
The fire alarm panel activates the flashers or the sounders, turns on sprinklers (or they can be activated along with the detector), or makes a call to the authorities or to the occupants. If the fire alarm system is addressable, the source of the occurrence will be pointed on the control panel. Users on separate floors or in connected buildings can be notified in several ways: by horns, gongs and loudspeaker messages advising appropriate action for each department.
Most advanced fire alarm systems use wireless technology and smart devices to protect and manage automated buildings from a remote control panel, typically a mobile app that can be downloaded, installed and managed from a smartphone.
The computerized logic of the control panel analyzes multiple detectors at the same time to decide on the most appropriate course of action. These modern smart fire alarm systems are more sensitive than classic models and are better at avoiding false alarms. With better design and stronger resistance, they can be placed in areas difficult to reach and give instructions about the best escape route to the people in the building. Smart fire alarm systems can perform integrated automatic actions, for example, discharge fire-suppression systems in closed designated areas; and vary the notifications to support people on their way out, while protecting expensive electronic equipment inside.
Smart wireless detectors use long-life batteries that can last up to 7 years. That is the shelf life of the smart unit itself. The smart sensor is activated by connecting it to a mobile account via a sim card. Users can activate, deactivate and assign fire alarm functions to each sensor from anywhere. Two big bonuses of most advanced fire alarms systems are the sleek design and the more pleasant audio warnings that don’t build upon the panic that’s already there.
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