How to Avoid Chimney Fires: Essential Tips for Homeowners

 

Chimney fires can be a devastating event for homeowners, leading to extensive damage and posing serious safety risks. Understanding the causes and implementing preventive measures is crucial for maintaining a safe home environment. This article will explore effective strategies to avoid chimney fires, ensuring that your fireplace or wood stove remains a source of warmth and comfort rather than a potential hazard.

Understanding Chimney Fires

Chimney fires occur when the buildup of creosote—a highly flammable substance formed from burning wood—ignites within the chimney flue. This can lead to flames shooting out of the chimney, causing significant damage to the structure and potentially spreading to other parts of the home. Recognizing the signs of a chimney fire and understanding its causes is the first step in prevention.

Causes of Chimney Fires

1.       Creosote Buildup: The primary cause of chimney fires is the accumulation of creosote, which can ignite when exposed to high temperatures. All types of wood create creosote. 

2.       Improper Burning Practices: Burning unseasoned wood or using excessive amounts of fuel can lead to incomplete combustion, resulting in more creosote production.

3.       Obstructions: Debris, animal nests, or blockages in the chimney can restrict airflow, increasing the risk of a fire.

4.  Improper Maintenance: Lack of proper maintenance, including sweeping to remove creosote, and inspections to check the condition of the chimney, can lead to chimney fires. 

Regular Inspections and Maintenance

Annual Chimney Inspections

One of the most effective ways to prevent chimney fires is to schedule annual inspections with a certified chimney sweep. These professionals will thoroughly examine your chimney for any signs of damage or buildup and perform necessary cleanings.

What to Expect During an Inspection:

·         A thorough cleaning of the flue to remove soot and creosote.

·         An inspection with a Chimney camera, visual inspection, and a detailed condition report outlining any issues
       found.

·         Recommendations for repairs or maintenance.

Cleaning Your Chimney

Regular cleaning is essential to prevent creosote buildup. Homeowners should consider the following:

·         Frequency of Cleaning: If you use your fireplace frequently, aim for at least two cleanings per year. For occasional use, an annual cleaning may suffice. For wood stove burners: at least twice during the season. 

·         DIY Cleaning: If you choose to clean your chimney yourself, ensure you have the right tools, such as chimney brushes and rods, and follow safety precautions. This is not recommended because homeowners usually will not know how to identify problems with the chimney system. 

Proper Wood Burning Practices

Use Seasoned Wood

Burning seasoned wood is crucial for minimizing creosote buildup. Seasoned wood has been dried for at least six months, reducing moisture content to 20%, and producing less smoke.

Identifying Seasoned Wood:

·         Look for cracks on the ends of the logs.

·         The wood should feel lightweight and produce a hollow sound when struck together.

• Use a moisture meter to measure moisture content
  

Control Airflow

Understanding how to manage airflow in your fireplace or wood stove can significantly impact combustion efficiency.

·         Adjusting the Damper: Ensure the damper is fully open when starting a fire to allow for maximum airflow. Once the fire is established, you can adjust it to maintain a steady burn.

·         Avoid Overloading: Do not overload your fireplace or stove with wood, as this can lead to smoldering fires that produce more creosote.

Installing Safety Features

Chimney Caps

Installing a chimney cap can help prevent debris and animals from entering the chimney, which can obstruct airflow and increase fire risk.

·         Benefits of a Chimney Cap:

·         Keeps out rain and snow, reducing moisture buildup.

·         Prevents animals from nesting in the chimney.

Monitoring Fire Conditions

Use a Chimney Thermometer

A chimney thermometer can help you monitor the temperature of the flue gases. Keeping the temperature within the optimal range (300-500 degrees Fahrenheit) can help prevent creosote buildup.

·         Signs of Overheating: If the thermometer indicates temperatures above 500 degrees, reduce the amount of wood being burned or adjust the airflow.

Recognize Warning Signs

Being aware of the signs of a chimney fire can help you act quickly if one occurs. Look for:

·         Loud roaring or popping noises from the chimney.

·         Flames or sparks shooting from the chimney top.

·         Smoke suddenly backing up into the home.

Emergency Preparedness

Know What to Do in Case of a Chimney Fire

If you suspect a chimney fire, it’s essential to act quickly:

•     Call Emergency Services: Dial 911 immediately to report the fire.
•     Close the Damper: If safe to do so, close the damper to limit airflow and help extinguish the fire.
•     Evacuate the Home: Ensure everyone in the home is safe and evacuate if necessary.
•   Keep watch for several hours after the fire has been extinguished. Sometimes fires or heat that escape      the chimney can ignite nearby combustibles in the walls or attic and smolder for hours. 

Keep Fire Extinguishing Tools Handy

Having the right tools on hand can make a difference in an emergency:

·         Fire Extinguisher: Keep a Class ABC fire extinguisher near your fireplace or wood stove.

·         Chimney Fire Extinguishers: Consider investing in specialized chimney fire extinguishers that can be deployed in case of a fire.

Conclusion

Preventing chimney fires requires a combination of regular maintenance, proper burning practices, and awareness of potential hazards. By following these guidelines, homeowners can enjoy the warmth and comfort of their fireplaces and wood stoves while minimizing the risk of fire. Remember, safety should always be a priority, and when in doubt, consult with a professional to ensure your chimney is in optimal condition.

By taking proactive measures, you can protect your home and loved ones from the dangers of chimney fires, ensuring a safe and enjoyable heating experience throughout the colder months.
__________________________

Marge Padgitt is a seasoned veteran in the chimney industry, with over 40 years of experience. She is the author of Your House is Killing You, Wood-Fired Heating and Cooking, and The Chimney and Hearth Pro's Resource Book. Reach her at www.chimkc.com or email margepadgitt@gmail.com. 

Tis the Season for Chimney Fires

 

By Marge Padgitt

Chimney Fire: Source: Marlboro FD, VA

It’s that time of year again – the season for chimney fires. As a chimney and fireplace service company we see the results of the lack of proper maintenance and improper installation that can cause fires and destruction of property, and in some cases injury or death. Chimney fires are preventable and should be avoided because of the risk that they could escape the chimney and catch the house on fire.  

All types of wood – even hardwood- creates creosote when burned. It accumulates on flue and smoke chamber walls and must be periodically removed. Chimney sweeping should be done by a professional chimney sweep who has the proper equipment to do the job right. First, tarps and a vacuum are set up. Then the sweep brushes the flue with wire brushes for masonry flues, or poly brushes for metal flues, and removes the creosote from the flue and fireplace or wood stove. Next, the sweep should run a chimney camera through the chamber and flue to inspect it and make sure there are no broken flue tiles, missing mortar, or blockages, or in the case of a manufactured fireplace or stove, that all of the metal pipe seams are solid and unwarped. The chimney sweep will then do a visual inspection of the interior and exterior chimney, check for proper clearance to combustibles and proper installation of components, then provide a report on its condition.

Chimney sweep  Source: Adobestock.com

It is very common for repair issues to arise with any type of chimney. Regular maintenance is
needed in order to keep the system functioning properly. Exterior masonry repairs should be done in the spring or summer, but if the chimney needs a new flue liner this can be done any time of year. Chimney fires can cause costly damage to a masonry or metal chimney system. If relining is necessary, it will cost thousands of dollars. Fortunately, chimney fires are covered by homeowner’s insurance. However, it is best to avoid a chimney fire in the first place.  

According to the U.S. Fire Administration there were 83,300 house fires caused by heating in 2018.  The National Fire Protection Association’s latest press release dated November 22, 2010 estimates that 66,100 home fires caused 1.1 billion in property damage, 1,660 injuries and 480 deaths in 2008, which was a 0.5% decline from 2007.  15,200 (23%) of all home heating fires are creosote fires, which the NFPA calls “failure to clean” fires that were confined to a chimney or flue, or involved solid-fueled space heaters, chimneys, connectors, and fireplaces.  See the entire news release at www.nfpa.org

Tips:

1.       Never burn a dry Christmas tree in a fireplace.

2.       Only burn dry, seasoned hard or soft cordwood in a stove or fireplace

3.       Only burn one piece of hedge to two pieces of other types of wood.

4.       Have the chimney inspected and swept annually, or twice per season if using a wood stove.

5.       Have a Draw Collar installed for hard-starting wood stoves.

6.       When purchasing a new home have the chimney inspected by a CSIA Certified Chimney Sweep prior to closing so you know what you are getting into.

7.       If you hear a whooshing sound, or freight-train like sound, or the room fills with smoke, get out of the house and call the fire department. Go outside and see if flames are shooting out the top of the flue.

 

See more information about chimney and fireplace maintenance and how to choose an appliance in Marge and Gene Padgitt’s new book Wood-Fired Heating and Cooking: How to choose, maintain, and operate a wood-burning appliance at Amazon.com or hearthmasters.net.

How to Avoid a Chimney Fire that Can Lead to a House Fire

House fire caused by flammable
creosote and improper construction

Creosote is a flammable substance that must be removed from the flue and smoke chamber periodically in order to avoid having a chimney fire. 

Since all wood creates creosote, including dry hardwoods, creosote is impossible to avoid when burning wood in a fireplace, wood-burning stove, circulating fireplace, or stove insert.

Creosote can only be removed by brushing the flue and chamber out with wire or poly brushes that are made especially for this purpose. Professional chimney sweeps know what size and type of brush to use for the type of flue system installed. There are many different types of venting systems, so knowing how to properly maintain each type is critical.

In a masonry chimney with a wood-burning fireplace the most common type of flue system is made out of vitreous clay tile, and the smoke chamber is usually made out of brick, stone, or block. This type of venting system accumulates more creosote than a stainless steel flue liner does because it is more porous.

Stainless steel flue liners don't accumulate as much creosote if they are properly insulated and installed correctly, but can be damaged by a chimney fire so maintenance is necessary.

Smoke chambers that are not parge coated with insulating mortar per IRC Code requirements allow more creosote accumulation due to their rough surfaces and corbels which decrease the flow of smoke and tar vapours.

The National Fire Protection Association and the National Chimney Sweep Guild recommend that creosote be removed after 1/8" accumulation on flue walls.

Gene Padgitt Sweeping a masonry chimney

The creosote being removed should be stage 1 which is very light and ash-like, or stage 2 which is more dense. If there is any accumulation of stage 3 glazed baked-on tar-like creosote, something is not right with the system, the fuel being used, or the operation of the appliance. Stage 3 creosote is the most flammable type, and is most often associated with chimney fires.

A chimney fire occurs when a spark ignites the flammable creosote, usually in the smoke chamber just above the damper, and flame may spread through the remaining fuel source (creosote) on the flue walls.

Stage 3 Creosote on flue walls

Chimney fires can be of short or long duration, but almost always cause damage to the smoke chamber and flue liner due to the quick temperature differential that occurs to the masonry during a chimney fire. Damages may occur to the face wall above the fireplace opening inside the house, to the back wall of the chimney, or to the top portion of the chimney and cement cap due to expansion. Fresh breaks may be found in the masonry and cement cap in a masonry chimney.

Burnt creosote that has been on fire

In a manufactured fireplace and metal chimney damages may occur to the metal smoke chamber and metal chimney pipe in the form of buckling, warping, and opening of seams. With a Class A chimney system serving a wood-burning stove, the same type of damage can occur.

In either case, the damage must be repaired, or parts replaced before further use because the system is no longer functional if it has damages.

Unfortunately, most chimney fire damage is found only during inspection of the system during routine chimney cleaning/inspection maintenance by a professional chimney sweep. Most chimney fires go unnoticed by homeowners when the fire occurs because they either don't recognize the whoosh of air and increased draft during a chimney fire, or are out of the room when it occurs and the fires goes out before they return.

Burnt, honeycomb creosote that has
been burned in a chimney fire

After a fire has damaged a chimney system, the flue liner and chamber may have cracks and gaps that would allow a second fire to escape to nearby combustible wood framing. This is how a house fire due to chimney fire commonly occurs. Another way a house fire can occur is if flame and sparks shooting out the top of the chimney catch the roof on fire.

chimney inspection with a Chim-Scan Camera

Water damage from rain and condensing acidic flue gasses often causes mortar joints between tile liner sections to deteriorate and leave gaps, which may also allow heat and flame to escape the flue system and cause a house fire.

The only way to know if the flue system has damages is to sweep it first to remove creosote, then run a special chimney camera through the chamber and flue. Photos may be taken with this type of camera. If damages are found, do not use the appliance until it is properly repaired by a professional chimney contractor.
 

Break in clay tile flue liner

In the greater Kansas City area, call HearthMasters, Inc. for chimney maintenance, repair, and building.  

www.chimkc.com

816-461-3665