The household smoke alarm consists of four parts: a sensor, a horn, a battery unit (or connected to a wire) and a circuit board.
When will the smoke be reported to the police?
(1) Producing flammable gases
In the initial stage of combustion, the first release of flammable gases, such as CO.
(2) Producing smoke
Smoke is a tiny suspended particle that can be seen with the naked eye. Its particle diameter is greater than 10nm. Smoke has a lot of fluidity, can sneak into the smoke sensor, is a more effective means of detecting fire.
(3) Generating flames
A flame is the light emitted by a substance that produces burning gas and is a kind of radiant energy. Flames emit infrared, visible, and ultraviolet light. Infrared and visible light are not suitable for fire alarm s, because heating equipment, electric lights, and solar light in normal use contain infrared or visible light. The ultraviolet light emitted by ultraviolet tube (exofielectric effect type) and some special semiconductor photoelectric-effect ultraviolet sensors can also be used to effectively monitor the ultraviolet rays emitted by the flame, but should avoid the sun's light exposure, so as not to cause false positives.
(4) Generating heat
By raising the ambient temperature, the material releases a large amount of heat when it burns violently, which can be measured using a variety of temperature sensors. But in very slow combustion, the rise in ambient temperature in the early stages of a fire is difficult to identify.