There are two types of fire alarms: ionization and photoelectric alarms. Both have practical uses in both residential and commercial properties. Ionization fire alarms provide excellent fire safety protection against quick-moving fires and detect flaming in the room. They're effective at detecting curtain or trash can fires, for instance. Photoelectric fire alarms, on the other hand, are more effective at detecting smoldering fires that start as a result of electrical shorts. Service 1st Fire Protection LLC installs dual-sensor alarms that combine both types into one system or one of each throughout your building.