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Fire Safety

Smoke Alarms and Home Safety

​​Smoke alarms save lives!

A smoke alarm is an often overlooked, but very important part of keeping your home safe. Many fire deaths happen in the home, especially at night or early in the morning when people are asleep. Death is usually caused by breathing in the smoke and toxic gases from the fire, not from being burned. Poisonous gases created during a fire, like carbon monoxide, can quickly cause a person to become confused and disoriented.

Once a fire starts it can spread quickly. In as little as 3 minutes, the heat from a small fire can cause everything in the room to burst into flames (called a flashover).

Studies show that death or serious injury due to fire is less in homes where smoke alarms were installed and maintained.

What is a smoke alarm?

A smoke alarm is a device that combines smoke detection and a loud alarm together in one unit. The alarm sounds if it detects smoke in large amounts, like in a fire.

A smoke alarm, when properly installed, tested, and maintained gives you an early warning of a fire, which increases your chances of getting out.

What types of smoke alarms are there?

There are two types of smoke alarms:
  1. Ionization:
    • Detects fast, flaming fires.
    • Detects smoke produced by flammable liquids, loosely packed light combustibles, and kitchen grease.
  2. Photoelectric:
    • Detects slow burning, smouldering types of fires.
    • Detects smoke caused by cigarettes burning in furnishings and bedding.

By law, smoke alarms sold in Canada must comply with the Underwriters Laboratories of Canada (ULC) Standard for Smoke Alarms, CAN/ULC-S531. ULC studies show that both types of alarms work equally well to detect smoke and sound a loud warning. Installing both types of smoke alarms within a home can increase safety.

Smoke alarms are powered by batteries or household electricity (hard-wired):

  • Battery: 9-volt batteries usually need to be replaced at least once a year.
  • Lithium battery: Some can last up to 10 years. Once installed and closed the battery can’t be taken out.
  • Hard-wired: uses the building’s power supply. It may have a battery back-up. It should be installed by a qualified electrician. New homes or new construction must, by code, have smoke alarms hard-wired to the building’s electrical system.


    Using a combination of both hard-wired and battery-powered alarms is recommended. Check with the local Building Safety Codes Officer for smoke alarm power requirements in new homes.

    Some smoke alarms may be manufactured with both the ionization and photoelectric features. Since most home fires are a mixture of smoke types, any type of smoke alarm will meet the needs of the average home. Always follow the manufacturer’s instructions for installing, testing, and maintaining the smoke alarm.

Under Alberta Law, all dwelling units (including rental units) must have smoke alarms. The Fire Code and Building Code have different codes for different types of buildings. Contact your local fire department or building branch if you have any questions about fire or building codes or how to install the alarm.

A dwelling is any type of housing. It includes:
  • apartment buildings
  • dormitories
  • hotels and motels
  • lodging houses
  • mobile homes
  • rooming houses

Where should smoke alarms be located?

There are two important things to remember when deciding where to put smoke alarms:
  1. Most fires start in the kitchen.
  2. Smoke alarms are to warn people asleep in bedrooms.

Install at least one smoke alarm on every level of your home, including the basement (but not in unfinished attics).

  • Put smoke alarms in the hallways that lead to each bedroom.
  • On floors without bedrooms, install the smoke alarm in or near each living area such as dens, living and family rooms.
  • Put a smoke alarm on the ceiling at the bottom of any staircase leading to upper floors.
  • Mount the smoke alarm high on walls or ceilings (remember—smoke and hot gases rise). Wall-mounted alarms should be placed at least 10 to 30 cm down from the ceiling. Ceiling-mounted alarm should be placed at least 10 cm away from the nearest wall. If ceilings are pitched, install the alarm near the ceiling’s highest point.

Where shouldn’t smoke alarms be located?

Smoke alarms shouldn’t be put in kitchens, garages, or bathrooms. This is because dust, steam, and exhaust can set off nuisance alarms (see “What are Nuisances Alarms” below). Nuisance alarms are often called “false” alarms. However, it isn’t a false alarm because the smoke alarm is doing what it is supposed to.

Don’t install a smoke alarm near a window or register, where drafts can affect alarm operation and sensitivity.

How do I care for a smoke alarm?

Smoke alarms must be kept in a clean condition to work, as dust and grime may affect how they work.

  • Replace the batteries at least once a year
  • Replace a smoke alarm every 10 years, sooner if it isn’t working.
  • Regularly dust or vacuum the unit.
  • Keep the unit free of paint, stickers, or other decorations that may prevent it from working properly.

Make sure the alarm is still working

Smoke alarms are electronic devices that age and can fail. Once installed, people sometimes have a false sense of security and don’t think to test the units regularly. Regular testing and maintenance is important to make sure the smoke alarm is working.

  • Press the test button at least once a month to make sure that power is going to the alarm and that it will go off when it detects smoke.
  • You can do a smoke test by blowing out a candle and letting its smoke to drift towards the alarm. The alarm should sound within 20 seconds. You can turn off the alarm by fanning the smoke away.
  • Tenants are responsible for testing and maintaining smoke alarms in their units—this includes changing the batteries. Tell your landlord right away if your smoke alarm isn’t working.

What should I do if the alarm goes off?

Every household should have a fire escape plan!
  • Have a home escape plan and make sure that everyone knows what to do.
  • Practice the pre-planned fire drill at least twice a year.
  • Identify two ways to get out of every room.
  • Decide on a meeting place outside the home.

What are “nuisance” alarms?

A smoke alarm going off when there is no real danger of a fire is called a nuisance alarm. Homeowners will often disable smoke alarms; however, doing this puts everyone in the home at risk in case there is a real fire, especially at night when everyone is sleeping.

If the alarm goes off often, try to figure out what the problem is. Below are some reasons for nuisance alarms:

Possible Cause

Reason Recommendation
Improper locationInstalled near the kitchen or bathroom, where smoke or steam can trigger the alarm.Don’t install smoke alarms near the kitchen or bathrooms.
Wear and tearSmoke alarms wear out, regardless of type or quality. The failure rate is very high after a unit is over 10 years old.Replace smoke alarms every 10 years.
Poor maintenanceThere may be more false alarms in a dirty or greasy environment. Dirt, dust, and cobwebs can collect in the unit, making it more sensitive.Regularly dust and vacuum smoke alarms.
Early installationAlarms installed too early during construction or renovation can become contaminated with dirt or dust.Install smoke alarms during construction and keep them covered, or install a new one after the work is finished.

Current as of: February 25, 2015

Author: Environmental Public Health, Alberta Health Services