Fine Fire Alarms
It seems like the question of how a fire alarm system works passes through everyone's mind at some point or another. Before that question can be answered, it is even more important for a person to know exactly what a fire alarm system is. Fire alarm systems are devices or series of devices that are meant to alert people and institutions to the presence of a fire within some building or another. In the industry, these systems are referred to as "active fire protection", which basically translates to mean that the system can be turned on or off, that is, activated, in some way or another.
Every single fire alarm system in the world operates on a simple principle, no matter what sort of form it takes. There are things working in it that tell it there is a fire, so called alarm initiating devices, things that let people who use it know there is a fire, the so called alarm notification appliances, things that it uses to try to prevent the spread of fire, the so called fire control units, and all the infrastructure that holds these three things together, all the electricity and wires that runs throughout the whole affair. All these things working in unison and correctly have often saved the lives of people who were in buildings that have caught fire.
Then, how does a fire alarm system work? Basically, it works by having the devices looking for fire being tripped. This can mean that a smoke alarm sniffs smoke and sends the signal to the system, or it can mean that someone sees a fire and pulls the alarm lever to let the system know that something is burning. At this point a sound too loud to be ignored is raised so that people will know there is a fire and can begin to get out of the building in an orderly fashion. Some fire alarm systems are equipped with strobe lights or the like so that people who are deaf can be alerted as well.
Nearly every single fire alarm system has a smoke detector installed on it in some location. This is because, as the old adage goes, where there is smoke there is fire. So one of the best ways to spot a nascent fire is to look for sign of smoke. Smoke detectors come in two flavors, those that use light and those that use air. The smoke detectors that use air look out the world with a beam of light and can detect when smoke scatters the signal of the light in a particular way. Those that use air "sniff" for smoke by analyzing the ionization of the air in the location where they are stored.