Your Guide to Home Fire Safety

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A smoke detector can provide vital early warning to protect you and your family from the perils of a home conflagration.
A smoke detector can provide vital early warning to protect you and your family from the perils of a home conflagration.
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Collapsed, the fire escape is smaller than a downspout.     
Collapsed, the fire escape is smaller than a downspout.     
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Extended by pivoting from the wall, it forms a stable ladder.
Extended by pivoting from the wall, it forms a stable ladder.
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Side braces prevent the ladder from swinging side to side.     
Side braces prevent the ladder from swinging side to side.     
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If you cannot find straight-gauge U-channel steel, try the combination of readily available parts pictured here.
If you cannot find straight-gauge U-channel steel, try the combination of readily available parts pictured here.
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Smoke alarms should be placed on each level of the house near bedrooms and stairwells. Ceiling locations are preferred, but walls are acceptable.
Smoke alarms should be placed on each level of the house near bedrooms and stairwells. Ceiling locations are preferred, but walls are acceptable.

Each year, between 5,000 and 6,000 people in the U.S. die as a result of structural fires, ranking it fourth as a cause of accidental death. Only car accidents, falls, and drowning claim more lives. Of these fatalities, more than 80% occur in one- and two-family homes.

Happily, there are significantly fewer fire deaths today than there were 10 years ago–this despite more than a doubling in property losses owing to fire during the same period. There’s a simple explanation for the declining number of deaths in the face of increasing dollar losses. It’s called the smoke detector.

Types of Smoke Detectors

There are two basic types of smoke detectors. An ionization unit contains a small amount (less than one microcurie) of a radioactive substance, such as americium-241. The decaying material fills one or two sampling chambers with ions of nitrogen and oxygen, which support a very small electrical current that keeps the alarm silent. Should smoke enter the chamber(s), however, the ions attach to the particles, and the current path breaks down, sounding the alarm.

Photoelectric smoke alarms rely on light scattering to detect smoke. As long as light emitted periodically by a diode (LED) fails to strike a photocell set out of line of the light path, the alarm stays off. But if smoke enters the light-tight chamber, the particles will reflect and refract the light onto the photocell, sounding the alarm.

  • Published on Nov 1, 1989
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