This is an interesting article about how fire alarms work; the author explains about the working process of fire alarms, for examples he tells us about the home alarm system for our safety, similar to that fire alarms also work in for our safety to protect us from the fire. In this article , you learn about what is fire alarm, how this device saves large number of people, then author explains about how do exactly fire alarms work and tell about types of detector that is used in fire alarm. Author breifly explain about the two types of detectors that are used in the fire alarm system. Then author gives some more points to be considered the working flow of fire alarm system.
Good article on fire alarm read it now : How Do Fire Alarm work