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Smoke Alarm Guidelines

Working smoke alarms save lives. Don't be foolish enough to think a barking dog will awaken you or that you will smell smoke - don't bet your life on it!

Toxic smoke and fumes kill. In a house fire, it is the flames that do the structural damage, but smoke is the primary danger to people. The majority of deaths in fires come from smoke poisoning.

Modern homes contain many materials, such as wood, wool, nylon and plastics, which when burning, produce heavy smoke and toxic fumes such as carbon monoxide and cyanide gas. These materials can smoulder for extended periods of time, producing substantial smoke and fumes before they burst into visible flames.

If you are asleep when a fire starts, you could suffer from smoke inhalation before you wake up. In fact, the combination of toxic smoke and gases and reduced levels of oxygen in the air can make waking up extremely difficult and in some circumstances, tragically impossible. So, it is essential to install and maintain working smoke alarms that will detect the smoke and sound an alarm.

Recent research indicates that house fires today burn faster and kill quicker than house fires 30 years ago. Research in the 1970s showed a safe escape time of 17 minutes. In 2005, this has decreased to an escape time of 3 minutes, or less in some circumstances. This drastic drop in escape time is primarily due to the contents of our modern homes, such as furnishings, that burn faster and more intently. This reduced escape time highlights the need for home fire escape planning and performing periodic practice drills.


  • Over 90% of residential fires in Ontario are preventable.
  • An injury is reported in 1 out of every 17 preventable home fires, and not all injuries are reported.
  • 1 out of every 100 preventable residential fires is a fatal fire.
Research from 1995 to 2004 regarding preventable, fatal residential fires in Ontario indicates:
  • 35% of fires - a smoke alarm was present and operated.
  • 25% of fires - a smoke alarm was present and did not operate.
  • 21% of fires - no smoke alarm was present.
  • 19% of fires - smoke alarm operation was undetermined.
This research pertains to 609 fatal fires that occurred in Ontario from 1995 to 2004. In about 50 per cent of fatal home fires, there was no smoke alarm warning. In the majority of these fatal home fires, it was determined a dead battery or no battery installed was the reason for the smoke alarm failing to activate.

Statistics also indicate the holiday season between November and the end of January to be the highest point of the year for fires and related fatalities. From November 1, 2004 to January 31, 2005, alone there were 35 fire fatalities in Ontario. This highlights the need to exercise extra caution during the holiday season when we may be most distracted.

(Statistical Source: Office of the Ontario Fire Marshal)

Visit the Ontario Fire Marshal's website to learn more about Ontario Smoke Alarm Status in Residential Fires 2003 to 2007

Often you hear people using the terms smoke alarms and smoke detectors interchangeably. However, there is a difference between the two. What's the difference?

A smoke alarm is an all-in-one, self-contained device, with a detector, which senses the products of combustion (smoke) and sounds an audible, and sometimes visual warning or alarm. Smoke alarms are widely used in residential settings. Put simply, a smoke alarm detects smoke and sounds an alarm.

A smoke detector is strictly a sensing device only, which senses the products of combustion (smoke) and sends a signal to a building's fire alarm system to activate an audible, and sometimes visual warning or alarm. Smoke detectors must be connected to a building's fire alarm system and are NOT a stand-alone unit. Put simply, a smoke detector senses smoke only and must be connected to a fire alarm system control panel. Smoke detectors are a detection device only - not an alarm.



There are two types of technologies used in smoke alarms to detect the presence of smoke or the products of combustion. Smoke alarms will employ one or both of these types of technologies. Each type of detector has its advantages and disadvantages.

Ionization smoke alarms activate more quickly for fast, flaming fires with little visible smoke. Photoelectric smoke alarms are particularly more responsive to smouldering fires and the dense smoke given off by foam-filled furnishings.

When properly installed and maintained, both types of alarms alert you to a fire and save lives. As in all things relating to your family's safety, buy the highest quality smoke alarm your budget will allow. Do not select a detector based solely on its low cost.

Smoke alarms are designed to be battery-powered or powered by a permanent connection to the household alternating current (AC) electrical supply (110v).
It is important when replacing smoke alarms that the correct type is installed. Smoke alarms that are installed with permanent electrical connections, also known as direct-wired or hard-wired smoke alarms, cannot be replaced with battery-powered units.

When purchasing a smoke alarm, look for a product that has been manufactured and tested to an acceptable standard, indicated by a marking for the Underwriters Laboratories of Canada (ULC), or Underwriters Laboratories Incorporated (cUL).

Ionization Smoke Alarms

Ionization smoke alarms use a small amount of radioactive material that ionizes the air between two electrically charged plates, causing a current to flow between the plates. When smoke enters the chamber, it changes the flow of current, which is detected and activates the alarm.

Ionization smoke alarms activate more quickly for fast, flaming fires with little visible smoke.

  • Cheaper than other types of smoke alarms
  • Very good with fast flaming fires with little visible smoke
  • Suitable for general use
  • Less prone to false alarms due to dust and steam
  • Very susceptible to nuisance alarms due to cooking
  • May be slow to respond to slow smouldering fires
  • Contain radioactive material

Photoelectric (Optical) Smoke Alarms

A photoelectric (optical) smoke alarm "sees" the smoke. NOTE: The term photoelectric does not refer to the power source for the smoke alarm. The power supply can be battery or direct-wired on the household electrical current (110v A/C). Both types are available to the consumer. Photoelectric (optical) smoke alarms operate on the principle of light scattered from the surface of particles. Smoke entering the sensing chamber reflects light onto the sensor, which triggers the alarm. Because large particles have much more surface area than small particles, a photoelectric smoke alarm is more sensitive to the large smoke particles produced in a smouldering fire.

Photoelectric (optical) smoke alarms are particularly more responsive to smouldering fires and the dense smoke given off by foam-filled furnishings.

  • Good for smouldering fires and dense smoke
  • Not as prone to cooking nuisance alarms
  • Contain no radioactive material
  • Suitable for general use


  • Prone to nuisance alarms from dust and insects - must be kept clean
  • More expensive
In the normal case, the light from the light source shoots straight across and misses the sensor. When smoke enters the chamber, however, the smoke particles scatter the light and some amount of light hits the sensor, activating the alarm.

Learn more on the HOW STUFF WORKS WEBSITE at

Combination Ionization / Photoelectric (Optical) Smoke Alarms

Combination Ionization / Photoelectric (Optical) alarms combine the two technologies, ionization and photoelectric, to detect the presence of smoke or products of combustion. An alarm can be activated by either of the sensors within the unit. A combination Ionization / Photoelectric (Optical) alarm gives you the benefits of both types of technologies.

Combination Smoke Alarm / Carbon Monoxide Alarm

Smoke alarms that combine carbon monoxide detection and smoke detection capabilities are also available in a single unit. These units incorporate different sounding alarms, or in some cases voice alerting of "Fire / Fire" or "Warning Carbon Monoxide" when detecting the presence of smoke and/or carbon monoxide. If a combination smoke alarm / carbon monoxide alarm is used, it must be installed on the ceiling to ensure that it will detect smoke effectively. Follow the manufacturers instructions.

Battery-Operated Smoke Alarms and Direct-Wired or Hard-Wired (A/C) Smoke Alarms

A 9v alkaline battery powers most battery-operated smoke alarms. Some manufacturers also offer battery-operated smoke alarms powered by a long-life lithium battery.

The Ontario Building Code has required direct-wired smoke alarms be installed in all new home construction since 1986, with amendments and additional requirements over the years.

When smoke alarms are being replaced, the replacement unit must not reduce the level of detection required by the Building Code in effect at the time of construction of the residence, or by municipal by-laws in effect before the Fire Code adopted this requirement. This requirement is contained in Sentence the Fire Code. In other words, existing direct-wired or hard-wired smoke alarms or electrically interconnected smoke alarm installations must be maintained to provide the same level of protection as originally required. Any replacement smoke alarms must be of a type comparable to the original or better. Any smoke alarms installed in addition to the requirements of Section 2.13 of the Fire Code are permitted to be battery powered.

Direct-wired smoke alarms can be "interconnected" or linked to one another, which means that should one smoke alarm activate in the home it will automatically sound the alarm on all smoke alarms within the home that are connected. People who sleep with their bedroom doors closed or may have difficulty awakening to a smoke alarm sounding outside the sleeping area should strongly consider installing interconnected direct-wired smoke alarms in their home.

Remember, smoke alarms connected directly to your home's electrical power supply (A/C) will not work during hydro outages unless they have a battery back up feature. Some older models of these alarms do not have an internal battery backup. Find out what type of alarms you have in your home and ensure you are protected by battery operated smoke alarms in the event of a power failure in your home.

Smoke Alarms for the Deaf, Deafened or Hard of Hearing

Both the Ontario Building Code and Ontario Fire Code require the installation of smoke alarms in residential occupancies. By definition, a smoke alarm must sound an audible alarm to alert the home's occupants. Unfortunately, an audible alarm may not alert an individual who is deaf, deafened or hard of hearing.

There are numerous smoke alarms available on the market today that address the specialized needs of these individuals. Some devices utilize a bright flashing strobe light, as well as an audible alarm, to alert the residents in the event of a fire. Due to the electrical supply requirements to operate these strobe lights, they must be wired directly into the home's 110v A/C electrical system. Some models have a 9v battery backup that will ensure the audible alarm will activate in the event of a power failure, however the battery will not activate the strobe light.

Additional options also exist that allow the individual to connect their smoke alarms to an alerting system that may incorporate a flashing strobe light, vibrating pager and/or vibrating bed shaker to alert the resident to the emergency. Other suitable options are also available.

A catalogue detailing all available options for the deaf, deafened or hard of hearing is available through The Canadian Hearing Society. You can contact The Canadian Hearing Society in Windsor by calling 519-253-7241 (TTY: 519-254-1704). Their Head Office contact numbers are 1-800-465-4327 (TTY: 1-800-537-6030) and their website is

Smoke Alarms featuring "HUSH" Control Feature:

Cooking vapours and steam can sometimes activate a smoke alarm when no fire emergency is present. These are considered nuisance alarms and are the primary reason for people illegally disabling their smoke alarms by removing batteries or disconnecting the power supply to their smoke alarms. This practice of disabling a smoke alarm is extremely dangerous and against the law!

The Office of the Ontario Fire Marshal has introduced a website, , giving detailed instructions on ways to eliminate nuisance alarms. As well, smoke alarm manufacturers offer smoke alarms with a "HUSH" or "PAUSE" feature that allows the resident to temporarily silence the nuisance alarm. Generally, the HUSH feature will silence the alarm for approximately 7 minutes and then automatically reset itself. The smoke alarm will indicate that it is in HUSH mode by use of a periodic "chirp" or a visual indicator, such as a flashing LED light.

NOTE: Dense smoke will override the "HUSH" control feature and sound a continuous alarm to alert you to a fire emergency.

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Roger 705-795-8255

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