Definition - What does Fire Alarm mean?
A fire alarm is a standalone device or a complete network of devices, installed in a building or an area, which gives audible and/or visible warning of an outbreak of fire in that building or area. A fire alarm system could be automatic, semi-automatic or manual. Fire alarm systems are mandatory in buildings, industrial installations, markets, offices, living spaces, public areas and some kinds of transports.
Safeopedia explains Fire Alarm
Fire alarms are generally audible and/or visible, mechanical or electrical signals or intelligence, indicating a fire incident that requires emergency actions such as fire-fighting, emergency services and evacuation from a building or an affected area.
There are many different types of fire alarms and combinations depending on the location, occupants of the location, noise environment, legal requirements and choices. The types used singularily or in combinations include:
Bell or gong - manual or electrical
Siren - electrical
Hooter - electrical
Emergency voice alarm communication systems - electrical
Flashing or rotary warning lights - electrical
A fire alarm system is comprised of three main stages:
Detection - manual (at the sighting of flame or smoke and burning smell) or automatic (heat or smoke detectors). There are chances of false alarms with automatic detection
Signal initiation - manual (pull or push bell electric or manual), semi-automatic (through a system panel that requires manual confirmation) or automatic (there are chances of false alarms)
Occupant notification - manual, semi-automatic (auto detection, manual confirmation and notification) or automatic (there are chances of false alarms)
Some fire alarms are combined with automatic fire extinguishing systems hence work as occupant notification and evacuation warning signal.