Smoke Alarms

Buying Time
When a smoke alarm senses smoke, an alarm will automatically sound. Fires often generate lethal amounts of unseen smoke and fumes well before flames are visible and before heat makes residents feel uncomfortably warm. When carefully purchased, installed, and maintained, smoke alarms can prevent such needless deaths. Smoke alarms buy time to get out of the house fast -- before toxic fumes accumulate to lethal levels. Teach children what the smoke alarm sounds like and what to do - leave the building immediately by crawling under the smoke - when they hear it sound.

Quality
When Purchasing a smoke alarm, quality, not price, should be the determining factor. Check for the following:
  • Laboratory label insuring that samples of the model you are buying have been carefully tested
  • An alarm loud enough to awaken the family through closed bedroom doors
  • A malfunction signal, to warn you when batteries are worn out or weak
  • A manufacturer's warranty of at least 5 years
  • Ease in maintenance and cleaning, which should be simple, as by regular vacuuming and dusting
Types of Alarms
  • Ionization - This type contains a small amount of radioactivity that conducts electricity. Electric current flows continuously between two electrodes in the chamber. When smoke particles enter, they disturb this flow, causing the alarm to go off.
  • Photoelectric - This type contains a beam of light and a photocell within the chamber. When smoke enters, it deflects the beam, causing it to strike the photocell and set off the alarm.
Which is better?
Ionization alarms are more sensitive to the tiny particles of combustion that cannot be seen or smelled - those emitted by flaming fires. Photoelectric alarms are more sensitive to the large particles of combustion emitted smouldering fires. Consequently, ionization alarms will respond faster to flaming fires, and photoelectric alarms faster to smouldering fires. The differences between the two types are generally not critical, since the difference in response time in only a matter of a few seconds. Since most home fires produce a rich mixture of smoke types, with detectable amounts of both large particle and small particle smoke early in the fire's growth, either an ionization or a photoelectric alarm will meet most needs.
Placement
  • Buy as many smoke alarms as it takes to give your home complete coverage.
  • You increase you chances of survival with each one that you have, but one on each level of the house is the absolute minimum.
  • You should have a smoke alarm in a bedroom if the occupant smokes or sleeps with the door closed.
  • When bedroom doors are left open, you should have at least one in the hallway outside the bedroom area
Detector placement diagram
Installation
  • Follow the manufacturer's installation instructions.
  • On the ceilings, mount the device away from corners and walls, which have dead air space nearby. About 8 to 10 inches is the recommended distance.
  • On walls, install the alarms high, because smoke rises, and place them from 8 to 10 inches away from corners and ceilings.
  • Install smoke alarms at least 3 feet from vents, which might recirculate the smoke.
  • Never place smoke alarms on uninsulated interior and exterior walls or ceilings. The difference in temperature between the interior and exterior can ruin batteries and prevent smoke from reaching the alarms.
Maintenance
  • Check smoke alarms monthly by pushing the test button. If you cannot reach the button easily, use a broom handle.
  • Change the batteries in your alarms twice a year - perhaps when you change your clocks for Daylight Savings Time.
  • If cooking smoke sets off the alarm, do not disable it. Turn on the range fan, open a window, or wave a towel near the alarm.
  • Do not remove the batteries to put in other appliances such as personal stereos or games.
  • Smoke alarms wear out over time. Replace yours if it is 10 years old or more.