Preventing Flue Fires
by Ben Spong – WVU Extension Specialist
Reviewed by Mark Lambert – Director of WVU Extension Fire Service 1/12/1
As temperatures begin to fall and your family starts to spend more time around the fireplace, it’s imperative that your fireplace and chimney are functional, clean and safely exhausting smoke and other gases away from your living spaces.
In 2011, the US Consumer Product Safety Commission reported 24,400 fireplace or chimney fires that resulted in 30 deaths, 90 injuries and $88 million dollars in property loss. Many of these fires may have been prevented by proper cleaning and maintenance.
The benefits of seasoning firewood
As you get ready to use your fireplace this season, start by ensuring your firewood is properly seasoned. Fresh cut wood can have 60 percent or more of its weight in water, which results in the fire’s energy going to evaporate water, rather than heat your home. Seasoning wood is easy – stack and loosely cover the wood, allowing air to circulate and dry the wood. A typical seasoning time period is 12 months.
When burning non-seasoned wood, a tarry substance called creosote will condense on the interior of the chimney more rapidly than when burning seasoned wood. Thick multiple-inch layers of creosote can coat your chimney after a single season, restricting the airflow and acting as a flammable fuel that can lead to chimney fires.
An annual professional inspection of your chimney is important to detect creosote buildup and other potential problems with your chimney. It is critical to correct any problems before using your fireplace again.
A preliminary do-it-yourself inspection is easy, but first make sure to put on safety goggles and a disposable dust mask.
Confirm that air is moving up through the chimney. This can be tested using a hanging tissue taped to the top front of the fireplace and visually looking to see which way the air is moving.
With a powerful flashlight and a fireplace poker (or similar tool), scratch the black surface of the smoke chamber (area above the damper). A shallow groove or scratch less than 1/8 inch deep in the creosote indicates that cleaning is probably not necessary. If the groove is 1/4 inch or greater, do not use the fireplace until it has been cleaned, as this level creosote could ignite at any time.
Of course, if you are unsure that you are checking the correct place or the actual depth of the scratched groove, contact a professional before using the fireplace.
A creosote-filled chimney can be swept using special tools that scrape the residue from the chimney walls and knock off any other soot and dust in the chimney. This is a messy job that requires a lot of tarps, buckets, vacuums and personal safety equipment. These services can be provided by professional chimney sweeps. The best companies are certified, knowledgeable about building construction methods, trained on deterioration and venting identification and have the tools to do the job quickly, cleanly and accurately.
With a safe, well-functioning fireplace and chimney, your family will be ready to enjoy the fire during upcoming cold, winter nights!