Chimney fires can be deadly. Even though chimneys are designed to withstand high temperatures and stop a fire from spreading to your home, they can fail if creosote in your chimney catches fire. Creosote is a highly flammable chemical compound that builds up in your chimney. A stray spark or high temperature in your chimney can ignite it. Chimney fires fueled by creosote can get to up to 2,000 degrees Fahrenheit. This can cause the chimney liner to crack and allow flames to spread to your home.
What is Creosote?
Smoke from a wood burning fire contains wood particles, gases, and other chemical compounds. As these combustion byproducts cool on their way up the chimney, they condense along the chimney walls. This condensation is what turns into creosote.
Creosote is extremely flammable. As it builds up, it passes through three stages. Each progressive stage is harder to remove than the last.
First Stage Creosote
When creosote forms, in the first stage, it is flaky and easy to remove. Professionals can quickly get rid of it with a basic chimney brush.
Second Stage Creosote
As more creosote builds up, it changes. It thickens and hardens into a shiny, glass-like compound that can’t be removed with a brush. Second stage creosote requires professional removal. CSIA-certified chimney sweeps typically use a power drill with a rotary loop to remove it.
Third Stage Creosote
If creosote continues to build up in a chimney, it moves on to a third stage. Third stage creosote is a thick, sticky tar-like substance. It is the most flammable at this point. It is practically a concentrated fuel. Third stage creosote also required professional removal by a CSIA-certified chimney sweep. In most cases, professional grade chemicals will be used to remove it. In severe cases of extreme buildup, it may be necessary to remove and replace the chimney liner.
You can prevent creosote buildup from reaching the third stage or causing a chimney fire by following the best practices recommended by the NFPA.
How to Minimize Creosote Buildup & Prevent a Chimney Fire
The National Fire Protection Association (NFPA) is a nonprofit organization that was founded in 1896 to help prevent house fires. They develop safety codes and best practices to reduce fires based off of their research. They are an authority on how to minimize creosote buildup and prevent chimney fires. Here are there top recommendations:
- Only burn dry, seasoned firewood.
Freshly cut wood is packed with moisture that makes it difficult to burn and produces dense black smoke filled with combustion byproducts. Allowing firewood to season, or dry out for at least six months, helps it to burn completely and produce less smoke.
- Never burn artificial logs.
Artificial logs produce more combustion byproducts than regular wood which significantly increases creosote buildup.
- Build hot, clean burning fires.
Stacking firewood with enough space between the logs for oxygen to circulate will produce a hotter, cleaner burning fire. If you consistently build efficient fires like this, less creosote will build up in your chimney because your fires will produce less smoke.
- Make sure the fire gets enough oxygen.
Open the damper in your fireplace before you light a fire to ensure it will get enough oxygen. If your fireplace has glass doors, it is a good idea to leave them cracked open slightly so that air can circulate.
- Reduce condensation by warming up a cold flue.
If your chimney isn’t well insulated, the flue can reach low temperatures. Lighting up your fireplace when the flue is cold will create more condensation and larger creosote deposits. You can easily warm up the chimney by rolling newspaper up to make a torch, lighting it and holding it up in the chimney. When you notice the smoke from the torch rising straight up, you’ll know that the flue is warm enough.
- Schedule an annual chimney cleaning and inspection.
The NFPA recommends an annual chimney inspection and cleaning because they have found that it is the most effective way to reduce the risk of a chimney fire. Professional chimney sweeps are trained to spot issues in your chimney that may pose a safety risk or increase creosote buildup. We also have the tools and training to safely and efficiently remove creosote.
Following these six recommendations will help you protect your home from a dangerous chimney fire. If you are looking for professional chimney cleaners that you can trust, give us a call at High’s Chimney Service. Our CSIA- and CCP-certified chimney technicians serve residents in Maryland, Virginia and Washington, DC.