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What You Must Know About Smoke Detectors

This is one of two weekends a year when it's recommended that you change the batteries in your smoke detectors, and make sure they're working right. Those weekends are when daylight-saving time begins, and when it ends in the fall.

Some 3,000 people die in house fires in the United States each year, and smoke detectors cut your chances of being trapped in a house fire by more than half, experts say.

On The Early Show Friday, consumer correspondent Susan Koeppen took a detailed look at different types of smoke detectors, and had plenty of tips about the devices.

The click here.

For word from a leading smoke detector maker, click here.

For a complete rundown of smoke alarm info from the CPSC, go to Page 2.

CPSC Daylight Saving Time Alert: Working Smoke Alarms Are Key to Surviving Home Fires

Smoke alarms are proven life savers. There are more than 300,000 residential fires every year, so when there is a fire, smoke alarms buy families valuable escape time.

Unfortunately, about two-thirds of fire deaths take place in homes with no smoke alarms or with non-working smoke alarms. The most common reasons why alarms did not work were missing, disconnected, or dead batteries. Consumers need to make sure that they have a working smoke alarm.

For better warning of fire, consumers should install smoke alarms on every level of the home, outside sleeping areas, and inside bedrooms. Replace batteries annually, and test the smoke alarms monthly. A good time to remember to replace batteries is when turning clocks ahead for daylight saving time on Sunday, March 9.

When shopping for smoke alarms, consumers should be aware of the two different types of smoke alarms: ionization and photoelectric. While both types are effective smoke sensors, ionization type detectors respond quickly to flaming fires, while photoelectric type detectors respond sooner to smoldering fires. Since consumers can't predict what types of fires might break out, CPSC staff recommends installing both ionization and photoelectric type smoke alarms throughout the home for the best warning of a fire. This recommendation is also supported by the United States Fire Administration, the National Fire Protection Association, Underwriters Laboratories, and by research conducted by the National Institute for Standards and Technology. There are also dual sensor smoke alarms that have both ionization and photoelectric sensors in one unit.

Consumers should also consider interconnected smoke alarms. Interconnected alarms are connected to each other by a hard wire or by wireless technology. If one alarm is triggered, all interconnected alarms in the home sound, alerting consumers to the fire earlier.

Many residential fires are preventable. CPSC recommends consumers follow these safety steps:
-- Never leave cooking equipment unattended.
-- Have a professional inspect home heating, cooling, and water appliances annually.
-- Inspect electrical cords for signs of wear, cracks, or age, and keep lighting away from combustibles.
-- Use caution with candles, lighters, matches, and smoking materials near upholstered furniture, mattresses, and bedding. Keep matches and lighters out of reach of young children.
-- Have a fire escape plan and practice it so family members know what to do and where to meet if there's a fire in the home. Children and the elderly may sleep through or not react to the sound of the smoke alarm, so parents and caregivers should adjust their fire escape plan to help them escape the house in the event of a fire.

For more information, also visit, for fire safety information from CPSC and other federal agencies.

Why are Smoke Alarms Important?

Every year in the United States, about 3,000 people lose their lives in residential fires. In a fire, smoke and deadly gases tend to spread farther and faster than heat. That's one reason why most fire victims die from inhalation of smoke and toxic gases, not as a result of burns. A majority of fatal fires happen when families are asleep because occupants are unaware of the fire until there is not adequate time to escape. A smoke alarm stands guard around the clock and, when it first senses smoke, it sounds a shrill alarm. This often allows a family the precious but
limited time it takes to escape. About two-thirds of home fire deaths occur in homes with no smoke alarms or no working smoke alarms. Properly installed and maintained smoke alarms are considered to be one of the best and
least expensive means of providing an early warning of a potentially deadly fire and could reduce the risk of dying from a fire in your home by almost half. Where Should Smoke Alarms be Installed?

Smoke alarms should be installed on every level of the home, outside sleeping areas, and inside bedrooms

A smoke alarm should be installed and maintained according to the manufacturer's instructions. When installing a smoke alarm, many factors influence where you will place it, including how many are to be installed. Consider placing alarms along your escape path to assist in egress in limited visibility conditions. In general you should place alarms in the center of a ceiling or, if you place them on a wall, they should be 6 to 12 inches below the ceiling.

Which Smoke Alarm Type is Better?

Although there are several choices to make in selecting the right smoke alarms to buy, the most important thing to remember is that smoke alarms save lives. For that reason, you should install a smoke alarm if your home does not have one. Smoke alarms may contain different or multiple sensors There are two main types of smoke alarms, which are categorized by the type of smoke detection sensor, ionization and photoelectric, used in the alarm. A smoke alarm uses one or both methods, sometimes with a heat detector, to warn of a fire.

Ionization detectors contain a chamber with two plates that generate a small, continuous electric current. When smoke enters the ionization chamber, the smoke particles disrupt the current flow, which triggers the alarm.

Photoelectric detectors use a light beam and light receptor (photocell). When smoke is present between the light and receptor, depending on the type of smoke chamber configuration, the reduction or increase of light on the photocell sensor triggers the alarm.

Smoke alarms may perform differently.

Both ionization and photoelectric detectors are effective smoke sensors. Even though both types of smoke detectors must pass the same tests to be certified to the voluntary standard for smoke alarms, they can perform differently in different types of fires. Ionization detectors respond quickly to flaming fires with smaller combustion particles; photoelectric detectors respond more quickly to smoldering fires. There are combination smoke alarms also that combine ionization and photoelectric detectors into one unit, called dual sensor smoke alarms.

CPSC staff recommends the following:
-- Install a working smoke alarm on every level of the home, outside sleeping areas, and
inside bedrooms.
-- Replace smoke alarm batteries at least annually, such as when resetting clocks in the fall
or spring.
-- Test all smoke alarms in your house once a month.
-- Do not place a smoke alarm too close to a kitchen appliance or fireplace, as this may result
in nuisance alarms.
-- Avoid locating alarms near bathrooms, heating appliances, windows, or ceiling fans.
-- Replace smoke alarms that are more than 10 years old. Smoke alarms don't last forever.
-- Develop and practice a fire escape plan, because working smoke alarms and a fire escape
plan will increase your protection in case of a fire.

The type of fire, slow smoldering or fast flaming, can determine the amount of time you have to
escape before being overcome by smoke, heat, and toxic gases. A slow smoldering fire may go
undetected for a long period of time before it erupts into dangerous flames and high heat. A fast
flaming fire has a very short amount of time before flames and heat become intense. In either type of fire, once out - stay out

Fast Moving Flaming Fire
Fast flaming fires don't leave much time for escape. An ionization smoke alarm may be seconds faster than a photoelectric smoke alarm, and those seconds will count in a fast moving flaming fire.

Smoldering Fire
Smoldering fires develop slowly. A photoelectric smoke alarm can be minutes faster than an ionization smoke alarm in responding to a smoldering fire. Regardless of the type of smoke alarm, as soon as the smoke alarm sounds, leave the home as fast as possible.

What Features Come on Smoke Alarms?
In addition to the type of smoke detection sensor, ionization and photoelectric, used in the alarm, moke alarms can be powered differently or be interconnected or single station alarms. Considering all of the available options will enable you to select the smoke alarms that may work best in your situation to effectively detect a fire.

Smoke alarms can be connected to the home's wiring system, battery powered, or a combination of both. Smoke alarms most often fail to alarm because of missing, drained, or disconnected batteries. A good reminder to replace the batteries in smoke alarms is in the fall or spring when resetting the clocks.

For older homes, battery-only smoke alarms are the simplest to install. For homes under construction, smoke alarms are typically connected to the household wiring (hard-wired). Smoke alarms connected to household wiring with battery back-up will provide protection even during power outages. Consider upgrading smoke alarms to hard wired with battery back-up during a renovation or remodeling project.

If your smoke alarm begins to chirp, signaling low battery power, replace the batteries immediately to prevent you and your family from being unprotected. Also make sure that everyone in the house understands how important it is to have working batteries in every smoke alarm and how dangerous it is to remove the batteries even for a short time. Smoke alarms with sealed lithium batteries can last up to 10 years; after 10 years, the entire unit is disposable


Interconnected smoke alarms may provide improved protection and offer more escape time in a fire. This type of smoke alarm allows all smoke alarms to sound if one has detected smoke. With interconnected smoke alarms, a fire in the basement, for example, will trigger the closest smoke alarm and alert all the occupants in the home by sounding all the smoke alarms. Not all homes have interconnected smoke alarms. Prior to 1989, existing homes typically had independent single-station, battery-only-powered smoke alarms. After 1989, new homes included hard wired, interconnected smoke alarms.

Interconnected smoke alarms are typically connected using a wire, but newer wireless technology is available that allows smoke alarms to be interconnected without using wires. This allows easier and less costly upgrade to interconnected smoke alarms for older homes. Not all homes may need interconnected smoke alarms. Small, single-level homes may not benefit from interconnected smoke alarms because of the close proximity between smoke alarms.

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