Smoke Detectors & Smoke Alarms

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Without a working smoke detector in the house, all of its occupants are sitting ducks in a fire. Many people mistakenly assume that if there was a fire in the house, they would be able to smell the smoke and wake up. Nothing could be farther from the truth. Smoke contains carbon monoxide, an odorless compound. It will not wake you up, no matter how good of a nose you have, but rather, it will put its occupants into a deeper sleep. So a good smoke alarm is necessary.

Studies show that 60 to 80 percent of fire fatalities are attributed to either a non-functioning smoke detector or no smoke detector at all. The presence of a working smoke detector is the first and most important step in child safety.

Types of smoke alarms

Photoelectric smoke detectors:
These work by directing a LED light into a dark chamber containing a photo cell, which is a light sensitive electrical component. When smoke enters the chamber it scatters the light, which then strikes the photo cell. When the photo cell’s voltage reaches a pre-determined level, the alarm sounds. Photoelectric smoke detectors tend to be better at sensing large, slow rising particles which are typical of smoldering fires. They are slower to recognize the near invisible particles released in a hot, fast burning fire.

Ionization smoke detectors:
These contain a small amount of radioactive material (generally 1 microgram or less of Americium 241, far too little to pose any risk to health by radiation), which ionizes the air within the sensing chamber. This gives it an electric charge that will conduct a current. When smaller more invisible smoke particles enter the chamber and disrupt the current, it sounds the alarm.

We strongly recommend that families purchase newer smoke detectors which contain both photoelectric and ionization sensors. Fire fighters have reported showing up to house fires in which a fire was ravaging the home. Despite having “working” smoke detectors, no fire alarms were sounding, because the home happened to have the wrong type of alarm – a slow, smoldering fire was not detected by the ionization detectors, or vice versa. This is too important of a threat to your family to ignore. If you do not have combination detectors, you should work both types into your system. It is recommended you have at least 1 ionization detector, either on the main level of your house or outside the sleeping areas, with the rest being photoelectric.

Checking the batteries in your alarm

  • Make sure that your smoke detectors are in good working order, with good batteries. Make a habit of replacing the batteries in your smoke detectors twice per year. Most people find it easy to change their smoke detectors whenever they change their clocks. If not, around the holiday season and around the fourth of July make good times, as people are a little more focused on fire safety then.
  • We would recommend that you use lithium batteries, which tend to last longer in smoke detectors.

Installing smoke alarms in your home

  • You should mount smoke detectors on a ceiling or high on a wall. The center of the ceiling is the best. If this is not feasible, move them to one side of the ceiling, but no closer to 6 inches to a wall. If you tuck them into a corner they may be much slower to register smoke. In a house fire where every second counts, this delay could be deadly.
  • One smoke detector is not enough. Equip your house with several . . . one in the kitchen, one on each level, and outside the bedrooms.
  • It’s best to have a system that is wired together, so that when one goes off, they all sound the alarm. If you’re financially capable of upgrading your home with a more professional system, it would be well worth it. It may even earn you some insurance discounts.

Testing your smoke alarm

Do a test run in your house. Pick a night after your children have gone to sleep to set off your smoke alarms. See if they wake up. Many smoke alarms are simply not adequate to wake a child in their sleep. If they don’t wake up, or if it takes a while for them to wake up, you will need to consider updating your system to something better. Or maybe a smoke detector closer to the sleeping area is needed. Check online for more advanced systems. (Read more about this issue in our article: When their life is on the line, will your child wake up?)

Teaching Children About Fire Alarms

  • Let your children hear the sound of their smoke detector, so that they know what it sounds like.
  • Explain to them that whenever they hear that sound, it means they need to get up right away and get out of the house as fast as they can.
  • Let your children be active in helping you maintain the smoke detectors, so their minds can keep focused on safety. When it is time to change the batteries, let your children help you with a ladder, or hold smaller children on your shoulders to help you change them. Keeping them constantly reminded of the smoke detectors in their home helps to ensure quicker recognition if they ever go off.

Read The Sound of Smoke to your children, in our kids academy fire safety lessons area.

If you have your families smoke alarms installed, check out these other fire safety issues:


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