A smoke alarm is a device that detects smoke, typically as an indicator of fire. Smoke alarms are usually powered by batteries and can be either ionization or photoelectric. Ionization alarms are more sensitive to fast-flaming fires, while photoelectric alarms are more sensitive to smoldering fires.
Smoke alarms are an important part of a home safety plan. They can provide early warning of a fire, giving you and your family time to escape. Smoke alarms should be installed in every bedroom, outside each sleeping area, and on every level of your home, including the basement.