Have you viewed those little round objects attached to the ceiling and marveled how they function and detect fume? We see them each day and everywhere but a bigger portion of us don’t know they operate. Since were talking about alarms and sensors, do you know that inside that small cylindrical object a little nuclear reaction happens? Let’s see how it these fire detectors work.

Currently, we have two types of fume detectors. The most common is the ionization detector. They work better than the other type which is the photoelectric detector. In addition, ionisation sensors are cheap and require tiny space when put in.

Ionisation Detector

The ionization detector utilizes 2 plates with opposite voltages and a little amount of Americium-241. A cell usually powers this voltage and are encased in a metal chamber where air can stream freely. The actual body of chamber functions as the negative plate and the positive plate covers the Americium. The Americium develops alpha particles which ionise oxygen and nitrogen atoms in the air within the chamber. What in reality takes place is nothing more than a bumping off of electrons. As the electrons are bumped off, the air atom becomes positively charged and attracts to the negative plate, while the electron gets drawn to the positive plate. Meanwhile, the electric circuits inside the detector senses if there are no disruptions to the pattern.

As air passes freely in the chamber, it becomes ionised. As smoke enters the chamber, the ionisation operation is broken up and consequently ignites the electrical horn to sound off.

Photoelectrical Detectors

Photoelectric sensors arent used as mostly because they arent that sensitive as most need a substantial amount of smoke to go off. Photoelectric sensors consist of two channels, one is to give out light and the other discovers it. If fume molecules are present in the air, this will interfere with the signal and the alarm goes off.

Most Fire Alarm Systems are bound together so if one gets an alarm, the entire fire systems go off. Some are even connected together with a water shower that mechanically goes off in the event of fire.