Would you know what to do, if in the middle of the night you woke up with smoke and fire in your home? That early warning, which can make the difference between a successful evacuation from a burning home and a tragedy, can come from an inexpensive smoke detector. For a very small price, you can equip your home with one of the best devices ever designed to prevent a family catastrophe.

Why have a smoke detector?

• Home fires are a serious threat to your family's safety. Approximately 5,000 people are killed and more than 40,000 are injured every year by residential fires. Billions of dollars worth of property damage is done by home fires. Most victims die from the smoke and toxic gases of a house fire, not because of burns, and many of these events occur at night while the victims are sleeping.
   
• A home smoke detector, when properly installed and maintained, is one of the best and least expensive ways to provide early warning of a house fire. Before the smoke reaches dangerous levels, or before the fire becomes too intense, the smoke detector alarm will go off. The risk of dying from fire is twice as high in homes that do not have functioning detectors. Remember to test your smoke detector(s) as recommended by the manufacturer.

So how does a smoke detector actually work?

• Smoke detectors work by sensing the rising smoke from a fire and sounding a piercing alarm.
   
• There are two types of smoke detectors on the market today:
  1. Ionization detectors use a radioactive source to produce electrically charged molecules (ions) in the air. This sets up an electric current within the detector chamber. When smoke enters the chamber, it attaches itself to the ions and reduces the flow of electric current, thus setting off an alarm.
  2. Photoelectric detectors sound when the smoke is dense enough to deflect a beam of light.
      
• Smoke detectors also differ by power source. Battery powered and household electricity.
   
• The batteries in battery-powered smoke detectors last approximately one year. When the battery begins to lose power and needs to be replaced, the detector will begin to emit "beeps" every minute or so. Some will keep this up for a week or longer.
   
• Smoke detectors that operate on household electric current operate as long as there is current in the circuit to which they are connected. However, they will not work in the event of a power failure, unless the unit has a battery backup. Plug-in units must be located near an electric outlet where they will not be unplugged or turned off by a wall switch. They should not get their power from a distant plug using an extension cord. Always use the hold-in clips to prevent accidental plug removal from the outlet.
   
• Here's a sobering fact to consider. According to the NFPA (National Fire Protection Association), only 6% of the homes in the USA do not have smoke detectors, yet 50% of home fire deaths occur in these homes.

So what kind of a smoke detector should I buy?

• Either type of detector is effective. Photoelectric detectors react more quickly to smoldering fires and Ionization units will respond faster to flaming fires.
   
• You may wish to buy at least one unit of each or a combination detector. However, because most home fires produce a mixture of smoke types with detectable amounts of large particle and small particle smoke early in the fire growth, either an ionization or a photoelectric detector will meet most needs.
   
• There are some special features available in smoke detectors. These include detectors that have an escape light that illuminates when the alarm is activated, portable units, or detectors that transmit their alarm to a central console by radio signal as part of a combined emergency alert system. These can be used with burglar and other warning or detection devices. As mentioned, electric current detectors with a rechargeable battery for power outages are also available.

So just how many detectors do I need?

• There should be at least one smoke detector on every floor of the house. Tests conducted by the National Bureau of Standards have shown that two detectors, on different levels of a two-story home, are twice as likely to provide enough time for escape as one detector. Although the upstairs detector senses smoke wherever it originates, the downstairs unit will react sooner to a fire that could block escape routes on the first floor.
   
• Having two detectors also allows you to select both an ionization type and a photoelectric model, or you can select one battery-powered and one plug-in or wired-in model. In this case, neither a battery failure or a loss of electrical power will leave your family unprotected.

So where should I place my detectors?

• Most smoke detectors can be installed easily. Please refer to the manufacturer's installation information for more details.
   
• Never hard-wire a detector to a circuit that can be turned off at a wall switch.
   
• Because smoke rises, each detector should be mounted high on a wall or on the ceiling to detect the first traces of smoke.
   
• For a wall-mounted unit, the top of the detector should be 4 to 12 inches from the ceiling.
   
• A ceiling-mounted detector should be placed at least 4 inches from any wall. If placed in a room with a high pitched ceiling, mount the detector on or near the ceiling's highest point.
   
• Remember, smoke and heat rises.
   
• Most home fires start in living areas - the den, family room or living room. On a floor with no bedrooms, install the required detector in or near the living area. If a stairway leads to an upper story, install the detector in the path where smoke would travel up the stairs.
   
• Don't install a detector near a window, door or air register where drafts could reduce its sensitivity.
   
• Locate a basement smoke detector close to the stairway leading to the floor above. But don't install the detector at the top of the basement stairs: dead air space near the door may prevent smoke from reaching the detector.