Fire detectors sense one or more of the products or phenomena resulting from fire, such as
smoke
Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwante ...
,
heat
In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, ato ...
,
infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
and/or
ultraviolet
Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...
light radiation, or
gas.
In dwellings, smoke detectors are often stand-alone devices. In non-domestic buildings, fire detection will typically take the form of a
fire alarm system, incorporating one or more of the following automatic devices:
*
Heat detector
*
Smoke detector
*
Flame detector
*
Fire gas detector
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Detectors
Active fire protection
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