There are two types of household use smoke alarms.

Ionization detectors
Ionization detectors contain radioactive material that ionizes the air, completing an electric circuit. Smoke molecules attach themselves to the ions causing a change in current flow that triggers an alarm. The radioactive, synthetic metallic element is called Americium. The amount is very small and not harmful.

Photo-electric detectors
These types of detectors contain a light source (usually a bulb) and a photocell, which is activated by light. Light from the bulb reflects off the smoke particles activating the photocell that triggers the alarm.

The placement of smoke alarms is very important. Follow these steps for proper placement and installation.

• One in each sleeping area
• One in a short hallway outside the bedroom.
• Hallways longer than 30 feet should have one at each end.
• Keep the alarm away from fireplaces, wood stoves and the kitchen to avoid false alarms.
• One at the top of each stairwell; smoke rises easily through stairwells.
• If putting a smoke alarm in the kitchen, be sure to keep it away from cooking fumes or smoking areas.

Proper mounting of a smoke alarm is important. Alarms can be self-mounted, but those connected to household wiring should have a separate circuit and be installed by a professional electrician.

• If mounted on the ceiling, keep it at least 18 inches away from dead air space near walls and corners.
• If mounted on the wall, place it six to 12 inches below the ceiling and away from corners.
• Keep smoke detectors high because smoke rises.
• Never place them any closer than three feet from an air register that might re-circulate smoke.
• Do not place near doorways or windows where drafts could impair the detector’s operation.
• Do not place on an uninsulated exterior wall or ceiling. Temperature extremes can affect the batteries.

Keeping smoke alarms in good condition very important and very easy. Follow these helpful tips to keep smoke alarms in good working condition.

• Always follow the manufacturer's instructions.
• Replace the batteries every year or as needed. Most models will make a chirping, popping or beeping sound when the battery is losing its charge. When this sound is heard, install a fresh battery, preferably an alkaline type.
• Replacing smoke alarms over 10 years old is recommended.
• Replace bulbs every three years or as needed. Keep extras handy.
• Check alarm every 30 days by releasing smoke or pushing the test button.
• Clean the alarm face and grillwork often to remove dust and grease.
• Never paint a smoke alarm as paint will hamper its function.
• Check the alarm if no one has been home for a long period of time.