How to Prevent a Chimney Fire

Learn how to prevent a chimney fire using this detailed guide that will help any wood burner work more efficiently and safely.


| January/February 1988



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SAFE STOVE INSTALLATION:  [A] CAP AND SPARK SCREEN[B] FLEXIBLE ATTACHMENT TO PREVENT STRESS-CRACKING[C] CHIMNEY TOP AT LEAST 3 FEET ABOVE ROOF PEAK[D] ROOFING AND RAFTERS HELD BACK AT LEAST 2 INCHES FROM THE CHIMNEY[E] AS MUCH OF CHIMNEY AS POSSIBLE INSIDE THE HOUSE[F] JOISTS HELD BACK 2 INCHES FROM CHIMNEY[G] CONNECTOR PENETRATES THIMBLE AT LEAST 3 INCHES[H] ALL JOINTS FIXED WITH SCREWS[I] TILE THIMBLE[J] AIR SPACE[K] TILE LINER APPROVED CATALYTIC WOODSTOVE IS PREFERABLE[L] CLEAN OUT


ILLUSTRATION: DON OSBY

Your best prevention is regular care by a chimney sweep. Here's what to do to prevent a chimney fire when that precaution isn't enough. 

How to Prevent a Chimney Fire

One of the true challenges of parenthood is facing questions like, "Mommy, where do the pieces of tree you put in the woodstove go?" What do you say? Do you launch into a speech on oxidation of carbon, vaporization of water, temperature-induced draft and flue gas velocity? Might as well invoke gremlins. A more honest and effective answer would be to explain that much of the wood turns into goo — a substance resembling day-old oatmeal, except it's black — that sticks to the inside of the chimney.

That glop is, of course, creosote, the wood burner's bane. It's a nuisance to clean out and a hazard to leave alone. Touched off by the right combination of heat and oxygen, creosote can show a demonic mind of its own, turning a normally smoky chamber into an inferno. Flame temperatures in a chimney fire can exceed 2,000 degrees Fahrenheit, sufficient to crack a flue liner or send showers of sparks onto the roof. More than 20% of all house fires are caused by woodburning appliances, and around half of those are related to chimney problems.

What Is It?

Creosote consists of particles and condensed vapors left over from the incomplete combustion of wood. It comes in many different forms — chimney sweeps identify types such as tar glaze, slag, flakes and soot — but all are combustible. Besides posing the threat of chimney fires, creosote is messy; it stains pipes, connectors, chimneys and roofs and corrodes metal parts of the chimney system. Some of its constituents may be highly carcinogenic.

The best way to combat creosote is to bum wood as completely as possible in one of the new clean-burning woodstoves. Look for a heater that has been certified by the state of Oregon's Department of Environmental Quality or the U.S. Environmental Protection Agency. However, an efficient stove is still no substitute for a good chimney system. The following suggestions will help any wood burner work more efficiently and safely.

Good Chimney Design

A properly designed and installed chimney will accumulate creosote more slowly than will an inadequate one, and it will be better able to withstand the ravages of a chimney fire, should one occur. If you're considering installing a chimney, take comfort in the fact that it doesn't cost a lot more to do it right; and if your present chimney doesn't measure up, consider the potential costs of neglect.

gretchen
9/3/2014 2:16:30 PM

This is an excellent article, because there are about 22,000 chimney fires each year in the United States which account for up to $100 million in damages and lost lives. As the article suggests, it is a good idea to keep a chimney fire extinguisher, such as Chimfex on hand. Chimfex puts chimney fires in as little as 22 seconds. The Chimney Safety Institute of America has awarded Chimfex with Accepted Product Status based on its ability to quickly and safely extinguish chimney fires. Find it and learn more at www.chimfex.com.


jack_27
11/29/2007 7:20:11 PM

I used a flare type to put out my chimney fire.. worked great. But now I cann't find any one that sells them .. could you help- Thanks , Jack






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