Installed in homes and businesses everywhere, a smoke alarm detector is a legally mandated fixture in all public buildings and commercial enterprises. In homes, smoke alarm detectors should be located at least one per floor to ensure timely notification if a fire breaks out. Smoke alarm detectors are offered by numerous brands, including Kidde and First Alert. Most are available for $20 or less, but wireless interconnected units can be much more expensive.
Smoke Alarm Detector Types
There are two basic types of smoke alarm detectors: ionization and photoelectric. Ionization smoke alarm detectors are able to pick up very fine, nearly invisible smoke particles using a trace amount of an ionizing radioactive element. Photoelectric smoke alarms sound when enough smoke is present in the chamber to redirect a light source to trigger a sensor. This makes photoelectric smoke alarms much more effective in detecting fires with large quantities of smoke.
Smoke Alarm Power Supply
Smoke alarm detectors can be wired into a home's power supply, plugged into a wall outlet or operate on a 9-volt or long-life lithium battery. Hardwired smoke alarms have a more involved installation, but feature a backup battery in case power should go out. AC-powered, plug-in smoke alarms must be installed directly on an outlet. Battery-powered smoke alarms work independently or can be wirelessly interconnected so that if one goes off, all other alarms do as well.