Smoke Detectors

Although many homeowners spend thousands of dollars to increase the value and comfort of their homes, they often overlook a simple measure that can help protect both their largest investment and the lives of their families.

Studies have shown that smoke alarms, when working, cut the risk of dying in a house fire in half. The sooner a fire is discovered, especially during sleeping hours, the less destructive and deadly the consequences. Thousands of lives have been saved by smoke detectors, but some homes still have none, many homes don't have as many as they should, and many of those currently installed are not working due to failure to replace batteries.

How Many and Where to Install

The main purpose of a smoke detector is to protect residents from fires while they are sleeping. Detectors should be located either outside bedrooms (if doors are left open) or in each bedroom (if doors are kept closed). You should also have one on each level of the home, so that any fires will be detected quickly before they spread. The detectors should be located either on the ceiling, at least six inches from the wall, or high on the wall, between six and twelve inches from the ceiling. They should not be located in kitchens or garages where cooking fumes or exhaust could set them off. If you want additional protection for these areas, consider a heat sensing alarm instead.

Smoke Detector Types

There are two main types of smoke detectors - photoelectric and ionization. Photoelectric detectors contain a source of light that shines into a chamber, along with a photocell that is sensitive to light. When smoke enters the chamber, it scatters the light and reflects it onto the photocell, which triggers the alarm. Photocell detectors react more quickly to smoldering fires, like a cigarette burning in a couch cushion. Ionization detectors contain a tiny radioactive cell that electronically charges molecules of air, creating particles called ions. These ions produce a continuous flow of electrical current that diminishes when smoke attaches to the ions. As the flow of current is reduced, the smoke alarm is triggered. Ionization detectors react more quickly to flaming fires. Both types work well in general, and if installing several you might consider one or more of each. Special alarms are available for the hearing impaired - they use a bright flashing light to signal the alarm.

Smoke detectors can be powered either by battery or standard household current ("hard-wired"). Most are battery operated and the batteries should be replaced once a year. Designate a specific day, like the day you set your clocks back from daylight savings time in the fall, and be sure to use the correct batteries (the battery type is usually printed inside or next to the battery compartment).

Hard-wired detectors require no batteries by are more difficult to install. They have a "power on" light to let you know the unit is working. Some hard-wired detectors include a battery backup in case the power goes out.

Maintenance and Replacement

Both types of smoke detectors should be tested monthly. If the testing mechanism is not working properly, the unit should be replaced right away. Along with replacing the batteries, it's a good idea to occasionally vacuum off any dust, cobwebs or insects. Be sure to read your owner's manual for any specific recommendations for that model.

Most smoke detectors have a useful life of about ten years. If yours are ten years old or older, you should replace them even if they seem to be working. New smoke alarms are relatively inexpensive, and considering the potential risks, a worthwhile investment.

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