Smoke Alarms

Smoke Alarms Save Lives!

From the National Fire Protection Association, U.S. Fire Administration and the Department of Homeland Security

Fire experts consider smoke alarms to be the most effective low-cost warning device available. They are the single most important means of preventing house and apartment fire fatalities by sounding an early warning signal. They are easy to acquire and simple to install and maintain. Do not buy smoke alarms unless it bears the label of an independent testing laboratory. There are several common types of home smoke alarms. Some smoke alarms are powered by batteries; others are designed to be plugged or hard-wired into a household electrical system.  

Most smoke alarms use one of two sensing systems for detecting a fire:

Ionization type smoke alarms pass an electric current through a sensing chamber.  When smoke enters the chamber, it interrupts the flow of current and activates the alarm.

Photoelectric type smoke alarms aim a light source into a sensing chamber.  Smoke entering the sensing chamber reflects the light onto the photocell and activates the alarm.


Heat and smoke rise, so all alarms should be installed high on a wall or on the ceiling. Install alarms on every level of your home. The National Fire Protection Agency recommends that you sleep with bedroom doors closed to slow the spread of smoke and fumes if there is a fire. Sometimes small children don't wake up to the sound of smoke alarms.Test the alarm outside children's bedrooms while the children are asleep to check their response. If people in your household sleep with doors closed, install interconnected alarms inside sleeping areas as well.  

Wall-mounted alarms should be installed so that the top of the alarm is 4 to 12 inches from the ceiling.

Ceiling-mounted alarms should be placed 4 to 10 inches from any wall. If the ceiling is pitched, mount the unit at or near the highest point.

Do not install near a window, door, fireplace or forced-air register where drafts could detour smoke away from the unit.

Position basement alarms close to the bottom of the stairs. Don't place the unit at the top of the stairs; dead air trapped near the closed door could prevent smoke from reaching the unit.


Batteries in smoke alarms should be replaced at least once a year. Pick a certain holiday, birthday or daylight-savings time to help you remember to replace the batteries. Many battery-powered smoke alarms will "chirp" to warn you that their battery power is too low.

Clean your smoke alarms twice a year by using a vacuum over and around the alarm to remove dust and cobwebs. Dirty alarms can degrade sensitivity.  Never paint any part of a smoke alarm.

Test alarms once a month. If your alarm doesn't respond to the manufacturer's recommended test procedure (usually pushing a test button), change it's batteries.  If it still doesn't perform, replace the alarm. Alarms will last 8 to 10 years. You can write the purchase date with a marker on the inside of your unit, then you will know when to replace it.

If you have a problem with nuisance alarms, due to cooking fumes or other non-fire causes, do not disconnect the alarm or remove the batteries. You may not remember to put the batteries back in the alarm after cooking. Instead, wave a towel near the alarm. Try another location or another model of alarm, but keep your home protected. Always be sure you understand why an alarm is sounding before you treat the alarm as a nuisance.

Plan and practice escape routes several times a year.

Make sure all family members know when and how to call emergency phone numbers.