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CMHC for Consumers November 2006

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The following fact sheet is part of the About Your House — General Series

Wood Heat Safety in an Emergency

This information is provided to help people use wood safely as an emergency heating fuel.

As most home heating systems need electricity to work, loss of power to a house can create a heating emergency. Many householders use their wood burning stoves and fireplaces to heat their homes during such an emergency.

A properly installed and operated wood stove or heating fireplace can be a safe and secure way to heat a home. But the use of wet wood, the use of make-shift, temporary wood stove installations, and the continuous use of decorative fireplaces increase the risk of a house fire. If it is possible, get professional help from a qualified chimney installer, a chimney sweep, or ask your local fire department for advice.

Getting the Best Out of Wet Wood

You may be forced to use wet wood, which is hard to light, slow to burn, and provides much less heat than dry wood.

Here's how to make the best of an emergency situation.

  • as small pieces heat up and ignite faster than large pieces, split the wood into pieces about 75 mm (3") in diameter;
  • brush snow and ice off the wood and bring it into the house — and be sure not to store it too close to the stove;
  • burn small, bright fires, using no more than five small sticks at a time;
  • if you have some dry wood, mix it with the wet wood;
  • never load up the stove or fireplace and let it smoulder.

Tips for Safe Operation

  • if you have a battery-operated smoke detector, make sure that it works. If you don't have one, try to install one;
  • check materials around the stove or fireplace and all exposed parts of the chimney, including in the attic, for signs of overheating. Wood starts to darken as it overheats;
  • make sure all flue pipe joints are fastened with no fewer than three sheet metal screws;
  • burn small, bright fires to make the most effective use of the fuel, while avoiding the overheating that results from burning large, intense fires;
  • don't try to heat the whole house; concentrate all your activities in the room where the heater is and let the rest go cold; drain down your water pipes and pumps;
  • shovel ashes into a metal container, take it outside immediately and empty it in the yard away from trees and shrubs; never put a bucket full of ashes in the basement or on a wooden porch floor, and never put ashes in a wood or cardboard box;
  • if the stove continues to smoke, open a nearby window;
  • if you can't keep the unit from smoking, stop using it because you and your family could suffer carbon monoxide poisoning;
  • if you are using a wood burning furnace, remove the blower compartment door and open the basement door; burn small, controlled fires.

Temporary Wood Stove Installations can be Hazardous

By far the most dangerous wood stove installations are those done in a make-shift way by untrained people. While installing a wood stove may seem a simple matter, a safe installation calls for a lot of specialized knowledge. A wood stove must have a proper brick or metal chimney -- never try to vent a wood stove out a window using single-wall flue pipes. Make sure the inside of the chimney flue is clear and smooth.

The flue pipes that connect the stove to the chimney are often the weak link. Every joint in the flue pipe assembly MUST be fastened with three sheet metal screws to prevent it from falling down as it heats. Flue pipes need at least 450 mm (18") of clearance from combustible materials like wood furniture and drywall. The stove should be located a least 125cm (48") from combustible materials. Most important, get professional help:

  • in Quebec, contract with a licensed installer or accredited chimney sweep; Association des Professionnels Chauffage (APC) is the licensing and accreditation agency; the full list of licensed installers and sweeps can be found in the APC magazine Plein Feu, which is on newsstands in Quebec now;
  • in other provinces, contract with a Wood Energy Technical Training (WETT) certified installer or chimney sweep;
  • or have your local fire department check your installation.

Look in the Yellow Pages for hearth dealers and chimney sweeps nearest you, or call the numbers at the end of this message to get more information. If you cannot get professional help, don't take any chances. It would be better to have to leave your home than to risk the safety of your family and others staying with you.

Be Careful with Decorative Fireplaces

The fireplaces in most homes are designed for fire viewing, not for serious heating. The continuous use of such fireplaces can be dangerous, particularly if large fires are burned. Since decorative fireplaces do not capture much of the fire's heat, it is usually better to leave the glass doors open to gain the direct radiant heat from the fire. The tempered glass in many of these fireplaces block this direct radiation.

To help avoid smoke spillage, bum one sheet of newspaper first to preheat the chimney. Build small, brightly flaming fires to gain the most direct radiation, without overheating the fireplace structure. To reduce the amount of warm air drawn out of the house into the fireplace, close the throat damper until the unit begins to spill smoke, then open it until the smoke stops. Never leave the unit unattended.

Put your Well Being First

Use your stove or fireplace safely. Don't risk your family's safety trying to save your water pipes. Move to a warm shelter until you can provide adequate heat.

For further information, please contact:

Canada Mortgage and Housing Corporation
1 800 668-2642 or www.cmhc.ca

The Hearth Patio, and Barbecue Association of Canada
(705) 788-2221 or www.hpbacanada.org

L’association des professionnels du chauffage
(514) 270-4944 or www.poelesfoyers.ca

Wood Energy Technology Inc.
1 888 358-9388 or www.wettinc.ca