Smoke Detectors And Fire Alarms

Smoke Detectors And Fire Alarms

Smoke Detectors And Fire Alarms,How to Choose a Smoke Detector

If a fire starts in your home, you may have as little as 2 minutes to evacuate. A well-chosen and working smoke detector, or smoke alarm, may double your chances of surviving the fire, according to the Kenya Fire Protection policy.

You have several options to consider in choosing a smoke alarm; here’s how to choose a smoke detector that’s right for your home.

Know the types of smoke detectors and their strengths and weaknesses. Smoke detectors detect smoke using one or more of the kinds of sensors described below.


Ionization alarms work by ionizing the air inside the smoke alarm with trace amounts of a radioactive element.

This sets up an electric current within the smoke detector. Smoke particles entering the ionization chamber disrupt the current, triggering the alarm.

Ionization alarms are better at detecting the tinier smoke particles from fires that ignite quickly, such as paper and grease Smoke Detectors And Fire Alarms or fires caused by arsonists. Some ionization smoke alarms are integrated with carbon monoxide detectors.


Photoelectric alarms use a small pulsating (strobe) light; smoke particles entering the detection chamber diffract the light onto a sensor to trigger the alarm.

 Photoelectric alarms are better at detecting the larger smoke particles from slow, smoldering fires, such as electrical fires or those in bedding, clothing, or upholstery.

 They are usually more costly than ionization alarms, but they are less susceptible to being triggered accidentally.


Dual-sensor smoke alarms incorporate both ionization and photoelectric sensor components. They are the costliest but provide the best smoke detection for home use. You can also buy both separate ionization and photoelectric smoke detectors and use them together.

Another type of smoke detector, the air-sampling smoke detector, uses a sensor in a network of pipes through which air is circulated, to determine whether smoke from a fire is present.

They are similar to ionization alarms but more sensitive and geared for business and scientific environments warehouses and laboratories where a higher degree of smoke sensing is called for.

Some manufacturers now offer “combination” alarms that include sensors for carbon monoxide in addition to smoke, which may be useful in homes having fuel-burning appliances or an attached garage.

 Note that sensitivity of CO sensors often does not last as long as smoke detectors, so combination units may need more frequent replacement.

Consider the way the smoke detector is powered. Many smoke detectors run on 9-volt, AA, or AAA batteries, which must be replaced periodically.

 Manufacturers suggest replacing the batteries once a year, when you adjust your clocks to go on or off Daylight Savings Time.

Some smoke alarms are equipped with lithium batteries designed to last for the 10-year life of the unit, while others are designed to be wired into household current and have backup batteries that kick in when the power goes out.

Some regulations now require all new homes or remodeled homes to have smoke alarms that are “hard-wired” to the household current and wired to each other, with or without battery backup.

Factor in the size of your house. You should plan to install a Smoke Detectors And Fire Alarms in each room of the house, including the basement and attic.

Also plan to put a smoke detector in each hallway that leads to a bedroom, as well as in the bedroom itself, and at either end of a stairway.

If you have a large house, consider getting a smoke alarm system where the individual smoke detectors are wired together so that when one detects smoke, they all sound.

These units usually have to be wired into household current and, thus, have to be professionally installed. Wireless, battery-powered, network alarms are also available.

Although using both ionization and photoelectric smoke alarms is recommended, you may want to use only photoelectric smoke detectors around the kitchen stove or toaster, as the more sensitive ionization detectors may be set off by cooking smoke.

Some smoke alarm units are not designed for use in attics, where they may be subject to very high or very low temperatures.

You may wish to consider installing a “heat detector” there instead of a smoke alarm, but that may require installation of an alarm control panel.

Look for a convenient way to test the smoke detector. Smoke alarms should be tested on a monthly basis to make sure the battery is not dead.

Most smoke detectors have a test button on the unit to verify that they work, but if you aren’t comfortable climbing on a ladder to test the alarm, choose a smoke detector that can be tested with the infrared signal from a remote-control unit, or with a long-handled tool.

Look for a unit that’s easy to maintain. Smoke detectors should be vacuumed once a month to remove dirt that can block their sensors or trigger false alarms.

Hinged or removable covers can make vacuuming easier. Also, some smoke alarms feature slides out battery drawers to make inserting new batteries easy, assuming the batteries are replaceable.

Look for the ability to turn off the alarm without disabling the unit. If you can’t shut the smoke alarm off when it sounds a false alarm, you may be tempted to take out the batteries and not put them back in when you need to have the smoke alarm work.

 Some units contain a so-called “hush” feature that may silence the alarm for a few minutes, while you search for the source of the alarm.

Consider any special needs you may have. Some smoke detectors come with options or add-on equipment to supplement the audio alarm, such as a visual alert system or a bed-shaker for the hearing-impaired. This option is usually available only as part of a network smoke detection system, however.

Recognize when your installation is large or complex enough that you need a professional installer, who may also recommend having a central panel and various sensors for smoke, heat, carbon monoxide attached.

The panel then activates annunciating devices such as horns, bells, flashing lights when there are alarm conditions. They may also contain diagnostic features to indicate “trouble” with a sensor or its batteries or wiring.

If you’re concerned about smoke/fire alarms when you are away from home, it is essential to have a means for the alarm system to call for help automatically.

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