Prevent a Chimney Fire!
Each year in the U.S. there are 25,000-plus chimney fires, which cause more than $125 million in property damage. A poorly maintained chimney can lead to a fast, loud, terrifying and destructive chimney fire—or a slow, quiet and eventually, equally damaging one.
Either way, you will not be able to control a chimney fire. It’s a true emergency, so call 911 immediately! Because firefighters have to fight the flames from the top of the chimney, they will send water flooding through your house, causing water damage on top of the fire damage. Simply put: you can lose your home to a chimney fire.
Fortunately, by performing regular maintenance and keeping watch for any signs of trouble, you can prevent most chimney fires. Read this article to understand what a chimney fire is, how it starts and how to stop one from occurring in your home.
Chimney Fires, Fast and Slow
With a fast chimney fire, you’ll first hear cracks and pops that could be as loud as gunshots, followed by a deep, rumbling sound. You’ll see black, flaming creosote falling into the firebox. And then, it’ll seem like an explosion. Flames will shoot out of the top of the chimney and back down into the firebox. Smoke will get pushed into your living space. Finally, the flue may crack, allowing flames to shoot into your walls.
Slow-burning chimney fires don’t get enough air or have enough fuel to burst into plain sight, but they can still be hazardous. You may not even know the fire took place until you get your chimney inspected. Still, the temperatures reached in a slow-burning fire are high enough to cause the same amount of damage to the chimney structure and nearby combustible parts of your home as their louder and more shocking siblings.
What Causes a Chimney Fire?
The job of chimneys that serve fireplaces and wood stoves is to expel the substances produced when wood burns. These by-products of combustion include smoke, water vapor, gases, unburned wood particles and more. These substances exit the fireplace or wood stove at high temperatures and flow up into the relatively cooler chimney, resulting in condensation and the eventual buildup on the inner walls of the chimney of a black or brown residue called creosote. The longer the smoke stays in the flue, the more likely it is that creosote will form. Creosote can be crusty and flaky, or sticky and drippy, or shiny and hardened—and each form is highly combustible. When creosote builds up on the inside of your chimney and the internal flue temperature gets high enough, a chimney fire can start and burn at up to 2,000°F.
Creosote is more likely to build up in your chimney if your fireplace or stove:
- is burning unseasoned wood
- isn’t pulling in enough air
- has cooler than normal chimney temperatures
What to Do if You Have a Chimney Fire
If you discover a chimney fire, immediately:
- Get everyone out of the house, including yourself
- Call 911
If you can do so—only without putting yourself at risk—take these additional steps to help save your home:
- Place a chimney fire extinguisher or fire suppressant into the fireplace or wood stove, which will consume oxygen and starve the fire
- Pour sand or baking soda onto the fire in the firebox (keep a bucket of sand nearby for this purpose)
- Close the glass doors on a fireplace or the air inlets on a wood stove
Once outside, use a garden hose to spray down your roof (not the chimney) to keep the fire from spreading while you wait for the fire department.
Once the chimney fire is completely out, call an expert fire damage restoration company like SERVPRO of West Hartford, who will remove all traces of damage, smoke and soot from your home and possessions.
And before you light another fire, hire a certified chimney sweep to inspect for damage to your chimney and fireplace, whether it’s masonry, prefabricated metal or a wood stove.
Prevent a Chimney Fire: Regularly Clean and Inspect
Every chimney is vulnerable to a chimney fire. It’s how you maintain your fire-burning equipment that makes the difference and keeps you safe.
Once oily, black, sticky creosote has condensed on the inside of your chimney, it will lurk there, building up and growing into a real fire hazard, until it is removed.
Additionally, rain, wind or animals can carry flammable debris into the chimney, which can quickly fuel a chimney fire if touched by loose embers from a fire. If a chimney is not protected by a flue cap, wind can blow leaves and twigs inside, and birds, squirrels and other vermin can build nests.
The best way to ensure that you never have a chimney fire is by cleaning and inspecting it regularly. A chimney sweep will remove both creosote and any debris that’s in your chimney. In addition, the sweep will inspect your chimney to detect:
- creosote built up to a honeycombed or puffy appearance
- warped metal in the damper, smoke chamber or chimney
- cracked, damaged or collapsed flue tiles
- discolored and/or distorted chimney cap
- creosote flakes and pieces on the roof or ground
- roofing material damaged by hot creosote
- cracks in exterior masonry
- soot deposits around mortar joints of masonry or tile liners
Try to have your chimney cleaned and inspected each year before fire burning season starts. (If you haven’t done it yet this season, call today before you light another fire!)
In addition to scheduling an annual chimney cleaning, you should pay attention to the condition of your chimney and fireplace. Schedule another cleaning when you notice creosote that:
- falls into the firebox during a fire
- resembles a honeycomb on the inside of the chimney
- is more than 1/4-inch thick
You’ll also want to do more frequent cleanings if you:
- burn fires more than a couple of times a week
- use a lot of artificial logs
- burn green or unseasoned firewood
Prevent a Chimney Fire: Pay Attention
In addition to scheduling an annual chimney inspection, you should watch for these indications that you may be headed for a chimney fire. If you spot any of them, call a certified chimney inspector before you light your next fire.
Buckling brick or stone
Look for cracking or settling of masonry inside the firebox or anywhere on the surround or hearth. Just a small gap can provide a direct route for sparks and high heat to reach the flammable parts of your home’s structure.
Soot in your firebox
If you notice crumbly black soot accumulating in your firebox, that may mean that creosote is building up, so call for a chimney cleaning.
Debris in your firebox
Of even more concern is finding what appear to be broken tile or pot shards in your firebox. Older homes may have masonry fireplaces with terra-cotta chimney liners, so finding these pieces may mean the liner has already been damaged by a chimney fire. Do not use your fireplace until it’s been inspected by a certified chimney sweep.
If you smell smoke beyond what you’re used to when you use your fireplace—or smell it outside the room the fireplace is in—extinguish the fire and call 911. Your local fire department will check for danger and damage to your chimney with heat-sensing guns or thermal imaging.
Changes in your walls
If heat has been escaping from cracked masonry, a damaged liner or an improperly installed prefab metal firebox, your home’s wood framing can become dry and charred and capable of igniting at a much lower temperature. Signs of excessive heat inside your walls include pictures falling off the wall or areas of bubbling or peeling paint. Call for an inspection if you see any of these changes.
Prevent a Chimney Fire: Prepare Your Fireplace
Beyond cleaning and inspecting your chimney and keeping an eye on potential trouble spots, you should always follow some best practices in preparing your chimney and fireplace or stove so that it burns efficiently and safely, every time.
Keep the damper open to maintain sufficient airflow during a fire (the damper is the metal plate in the flue that regulates the draft). This will allow enough air to quickly move heated smoke up the chimney. Likewise, when using a wood stove, avoid closing down the stove damper or air inlets too soon or too much. Overloading the firebox of a wood stove in an attempt to get a longer burn time also contributes to creosote buildup.
Insulate your chimney’s flue liner (the layer between the flue and chimney walls) to prevent flue temperatures from getting too cool, which can encourage fire by-products to condense and form creosote. Wrap a heat-resistant insulation blanket around the liner or pour an insulation mix such as vermiculite into the space between the liner and flue.
Install a chimney cap on the crown around the outside opening of the flue to keep debris and critters out of your chimney. A cap will also prevent acidic rainwater from entering and corroding the chimney.
Prevent a Chimney Fire: Burn Fuel That’s Clean, Never Green
When you start a fire, you want it to burn hot, fast and clean to create far less smoke, vapor and unburned wood particles, allowing little to no creosote to form in the chimney. On the other hand, low-temperature, slow-burning fires, particularly those left to smolder overnight, produce more smoke and leave behind more unburned combustible material. When that hardens into creosote on the chimney walls, there’s an increased risk of chimney fires.
Use the right fuel and build your fire the right way by following these tips.
Always burn seasoned hardwood. That means the wood has dried for at least six months and has a moisture content of 20 percent or less (you can test this with a wood moisture meter). When you burn green or unseasoned wood, energy is used initially just to evaporate the water trapped in the logs’ cells. This, in turn, keeps the resulting smoke cooler and more likely to condense in the chimney and form creosote.
Use the best fire starters for fuel, kindling and tinder, such as well-seasoned hardwood or CSIA-approved logs. Never use gasoline and kerosene to start a fire—these flammable liquids can quickly create a conflagration. And burn coal only in a coal-burning wood stove, because it can significantly raise the temperature in the flue, increasing the risk of a chimney fire.
Build a clean fire by using the top-down burn method, in which the largest logs are at the bottom of the fire and the smallest pieces at the top. Start by placing the largest pieces of wood in the bottom of the fireplace or wood stove, with the ends at the front and back, which allows the air to mix well with the fuel. Next, stack four to five smaller levels of wood on top of the first layer, each layer perpendicular to the one below, until the stack is about half the height of the fireplace. Then place kindling (the smallest pieces of wood) in smaller and smaller pieces, adding wood shavings or crumpled newspaper on top. Light the material on the top and the fire will gradually burn its way down to the largest logs.
Use dried twigs or branches for kindling and torn or crumpled newspaper or pine cones for tinder. Cardboard or glossy magazine pages contain chemicals that can emit toxins when burned.
Enjoy a Happy Ending to Your Fire
Before retiring for the night or leaving your home, always extinguish your fire safely and thoroughly. Use a fireplace poker to spread out the wood and embers, then shovel ash from the bottom of the fireplace to cover them. Next, completely cover the cooled wood and embers with baking soda, which will extinguish any remaining embers. After the firebox cools (for a minimum of three hours, but preferably eight), shovel the ashes into a metal container. Fill the metal container with water and store it outside your home and away from other flammable materials until you’re ready to discard them.
Enjoy your clean and safe fireplace, avoid a chimney fire … and live happily ever after!
If your home or business suffers damage from a fire, call SERVPRO of West Hartford today at 860.206.6141
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The team at SERVPRO of West Hartford has specialized training and experience in fire restoration and cleanup, as well as natural disaster and storm damage cleanup, water damage and mold remediation, and chemical and biohazard cleanup. Call SERVPRO of West Hartford (860.206.6141) any time.
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If your home or business suffers damage from a fire, call SERVPRO of West Hartford today at 860.206.6141