The International Association of Fire Chiefs suggests that each time you change your clock, you change the battery in you smoke detector.

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National Fire Protection Association
International Association of Fire Chiefs

The following information is courtesy of the National Fire Protection Association.

Smoke detectors aren't new. The technology has been around since the 1960s. The single-station, battery-powered smoke detector, similar to the one we know today, became available to consumers in the 1970s. NFPA estimates that 93% of U.S. homes have at least one smoke detector. They save so many lives that most states have laws requiring them in residential dwellings.

Still a Major Problem

Although 13 of every 14 homes have at least one smoke detector, almost half of home fires and three-fifths of fire deaths occur in the share of homes with no detectors. Thousands of people still die each year in home fires where smoke detectors aren't present.

In addition, there are now more homes with smoke detectors that don't work than homes without detectors at all. These poorly maintained units create a false sense of security among occupants. Approximately one-third of homes with smoke detectors that experience fires have smoke detectors that aren't working, and hundreds of people die each year in these fires.

Tragically, the grave importance of installing and maintaining smoke detectors has not yet been fully realized. Most people who die in home fires are not in the room where the fire starts; working smoke detectors alert people to fire and give them time to escape in a situation where minutes can mean the difference between life and death.

Working Smoke Detectors Save Lives

Having a smoke detector cuts your chance of dying nearly in half if you have a home fire. By properly placing, regularly testing and maintaining your detectors, you can ensure that they are in fact working and will alert you if a fire breaks out. Make sure you buy only those detectors that bear the mark of an independent testing laboratory. Some detectors operate using an "ionization" sensor while others use a "photo-electric" sensor. An ionization detector uses an extremely small quantity of radio-active material to make the air in the detector chamber conduct electricity. Smoke from a fire interferes with the electrical current and triggers the alarm. A photoelectric detector uses a tiny light source shining on a light sensitive sensor. The alarm is triggered when smoke from a fire interferes with the light. All tested and labeled smoke detectors offer adequate protection if they are properly installed and maintained.

Make Placement a Priority

A recent NFPA report on smoke detectors found that there is a substantial number of households that do not have the devices on every level of the home, as needed. The majority of fire deaths occur at night when people are asleep. NFPA's National Fire Alarm Code (NFPA 72) says homes must have smoke detectors on every level of the home including the basement and outside each sleeping area. New homes are required to have a smoke detector in each sleeping area as well.

To slow the spread of smoke and fumes if a fire develops, NFPA suggests that you sleep with your bedroom doors closed. If you sleep with your bedroom doors closed, install a smoke detector inside each bedroom. Detectors should also be installed in other areas of your home where people sleep. In new homes, the National Fire Alarm Code requires hard-wired detectors to be interconnected, so that if one detector is activated, all detectors will sound the alarm signal. On floors without bedrooms, smoke detectors should be installed in or near living areas, such as family rooms and living rooms.

Detectors that are hard-wired into the home electrical system should be installed by a qualified electrician. If your detector plugs into a wall socket, make sure it has a restraining device to keep its plug from being pulled out. Never connect a detector to a circuit that could be turned off at a wall switch. Most detectors are battery-powered and can be installed with a screwdriver and drill and by following the manufacturer's instructions.

Since smoke and deadly gases rise, detectors should be placed on the ceiling at least 4 inches from the nearest wall, or high on a wall, 4-12 inches from the ceiling. This 4-inch minimum is important to keep detectors out of possible "dead air" spaces, because hot air is turbulent and may bounce so much it misses spots near a surface. Installing detectors near a window, door or fireplace is not recommended because drafts could detour smoke away from the unit. In rooms where the ceiling has an extremely high point, such as in vaulted ceilings, mount the detector at or near the ceiling's highest point.

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Maintenance is a Must

What good are smoke detectors that don't work? No good at all! That's why it is imperative that you keep your smoke detectors fit and in good shape. It's easy. Maintain your smoke detectors by:

Testing

Whether your detectors are hard-wired or battery operated, NFPA recommends testing them once a month to make sure they are operating. A working smoke detector greatly reduces your chances of dying in a home fire. Testing is the only way to ensure they are working to protect you. Test each detector by pushing the test button and listening for the alarm. If you can't reach, stand under the detector and push the test button with a broom handle.

Replacing Batteries

If your smoke detectors are battery operated, replace their batteries according to the manufacturer's instructions. NFPA recommends doing this at least once a year or when the detector chirps, alerting you that the battery power is low. Replace the batteries immediately if you move into a new home. Make sure no one disables your smoke detectors by borrowing batteries for other uses. Everyone you live with should understand how critical it is to have working smoke detectors.

Cleaning

Just as you clean your home, your smoke detectors need to be cleaned. Make sure you follow the manufacturer's instructions about cleaning. Cobwebs and dust usually can be removed with a vacuum cleaner attachment. If you are going to be doing work nearby that could send dust in the air, cover the detector with a shield. Also, shield the detector if you are painting around it, and never paint on it. Remove the shield promptly after work is completed.

Dealing with Nuisance Alarms

Regularly cleaning your smoke detectors and following the manufacturer's instructions may help stop "nuisance" or false alarms. If this doesn't stop them, install a fresh battery in the detectors giving nuisance alarms. Evaluate where your detectors are placed if the problem still persists. Cooking vapors and steam can set off a smoke detector. If the detector is near the kitchen or bathroom, try moving it farther away. If nuisance alarms continue, install a new smoke detector.

No Substitute for Smoke Detectors

Fire protection in the home must start with smoke detectors. There are many other kinds of detectors which may be designed to detect such factors as high temperatures, rapid changes in temperature, and certain gases produced in fires. However, these detectors are not as effective as smoke detectors in giving the first warning when a fire breaks out. NFPA does not require heat detectors in homes, however, they may be used for optional extra protection in areas like kitchens, attics, and garages, where smoke detectors are susceptible to nuisance alarms.

Tests performed on the speed of warning given by smoke detectors and heat detectors for many types of typical home fires showed smoke detectors consistently give first warning- often by enough of a margin to make a major difference in your chances of escaping alive. Smoke and deadly gas spread farther and faster than heat.

Contrary to popular belief, the smell of smoke may not wake a sleeping person. Instead, the poisonous gases and smoke produced by a fire can numb the senses and put one into a deeper sleep.

Smoke Detectors Are Cost-Effective

A battery-operated smoke detector for the home retails for less than $10. Smoke detectors with extra features can cost up to $25. Batteries cost $1 to $2, depending on the brand. A smoke detector for a typical hard-wired system costs $14-$18. Smoke detectors for people with hearing impairments cost approximately $100 each. In 1994, home fires caused $481,000 in damage every hour.