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Smoke alarms and home safety

Smoke alarms save lives. A smoke alarm is very important for keeping your home safe. You can die in a fire at home, especially at night or early in the morning when you're asleep. More people die from breathing in smoke and poisonous gases (like carbon monoxide) from the fire than from being burned.

Fire can spread quickly. In just 3 minutes, the heat from a small fire can cause everything in the room to catch on fire (called a flashover).

Studies show that fewer people die or get seriously hurt in a fire when their homes have well-maintained smoke alarms.

What is a smoke alarm?

A smoke alarm is a device that detects (notices) smoke and sounds a loud alarm.

A smoke alarm, when properly installed, tested, and maintained, gives you an early warning of a fire so you have a better chance of getting out.

What types of smoke alarms are there?

There are 2 types of smoke alarms:


  • Detects fast, flaming fires.
  • Detects smoke produced by flammable liquids, loosely packed light combustibles, and kitchen grease.


  • 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 in your home can make it safer.

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 should be fine for the average home. Always follow the manufacturer’s instructions for installing, testing, and maintaining the smoke alarm.

Under Alberta Law, all dwelling units (any type of house, including rental units, dorms, hotels and motels, mobile homes, rooming and lodging houses) 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.

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 "nuisance" alarms?” below). 

Don’t install a smoke alarm near a window or register, where drafts can affect how it works.

How do I care for a smoke alarm?

Keep smoke alarms clean, because dust and grime may affect how they work.

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

How do I make sure the smoke alarm is still working?

Smoke alarms can get old and stop working. It's important to test and maintain your smoke alarms regularly 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 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.
  • Practise the pre-planned fire drill at least twice a year.
  • Have 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. Some people will take out the batteries or disconnect their smoke alarms because of nuisance alarms. Don't do this - it puts everyone in the home in danger, especially at night when you're sleeping.

If the alarm goes off often when there's no fire danger, try to figure out the problem. Below are some reasons for nuisance alarms:

Possible cause

Reason   What to do
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 tearAny smoke alarm can wear out. Your  smoke alarms shouldn't be older than 10 years.Replace smoke alarms every 10 years.
Poor maintenanceThere may be more false alarms in a dirty or greasy area. Dirt, dust, and cobwebs can collect in the smoke alarm and make it more sensitive.Regularly dust and vacuum smoke alarms.
Installed too earlyAlarms installed too early during construction or renovation can get dirt or dust inside them.Install smoke alarms during construction and keep them covered, or install a new one after the work is finished.

Current as of: September 28, 2021

Author: Environmental Public Health, Alberta Health Services