What is a smoke alarm?
Smoke alarms aren't new. The technology has been around since the 1960s. The single-station, battery-powered smoke alarm, similar to the one we know today, became available to consumers in the 1970s. The National Fire Protection Association (NFPA) estimates that 93% of U.S. homes have at least one smoke alarm. Smoke alarms save so many lives that most states have laws requiring them in residential dwellings.
 
Most people who die in home fires are not in the room where the fire starts; working smoke alarms alert people to fire and give them time to escape in a situation where minutes can mean the difference between life and death.
 
Even though they are widely used, almost half of home fires and three-fifths of fire deaths occur in homes with no smoke alarms. Tragically, thousands of people die each year in these home fires.
 
Homeowners should frequently check their smoke alarms. These poorly maintained smoke alarms create a false sense of security among home occupants. Wake County encourages you to regularly check your smoke alarms to make sure they are in proper working order.
 
Purchasing a Smoke Alarm
A working smoke alarm cuts your chance of dying in a home fire by about 50%. By properly placing, regularly testing and maintaining your alarms, you can ensure that they are, in fact, working and will alert you if a fire breaks out. Make sure you buy only those alarms that bear the mark of an independent testing laboratory. Some alarms operate using an "ionization" sensor while others use a "photoelectric" sensor. An ionization alarm uses an extremely small quantity of radioactive material to make the air in the alarm chamber conduct electricity. Smoke from a fire interferes with the electrical current and triggers the alarm. A photoelectric alarm 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 alarms offer adequate protection if they are properly installed and maintained.
 
Installing a Smoke Alarm
A recent National Fire Protection Association (NFPA) report on smoke alarms found that there are a substantial number of households that do not have smoke alarms on every level of the home. 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 alarms on every level of the home – including the basement – and outside each sleeping area. New homes are required to have a smoke alarm 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 alarm inside each bedroom. Alarms should also be installed in other areas of your home where people sleep. In new homes, the National Fire Alarm Code requires hard-wired alarms to be interconnected, so that if one alarm is activated, all alarms will sound the alarm signal. On floors without bedrooms, smoke alarms should be installed in or near living areas, such as family rooms and living rooms.
 
If you purchase a smoke alarm that is to be hard-wired into the home electrical system, a qualified electrician should complete installation. If your alarm plugs into a wall socket, make sure it has a restraining device to keep its plug from being pulled out. Never connect an alarm to a circuit that could be turned off at a wall switch. Most alarms are battery-powered and can be installed with a screwdriver and drill by following the manufacturer's instructions.
 
Since smoke and deadly gases rise, alarms 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 alarms out of possible "dead air" spaces, since hot air is turbulent and may bounce so that it misses spots near a surface. Installing alarms 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 alarm at or near the ceiling's highest point. In all cases, smoke detectors should be installed in accordance with the manufacturer's instructions.