Extinguishing Chimney Fires

BY JONATHAN RIFFE and LARRY PATIN

Although many fire departments respond to chimney fires in the winter months, how much time do they spend teaching recruits the proper method of extinguishing these fires? Chimney fires are easy to handle and mitigate if you take the right actions; however, you still need to be proficient. Following are some helpful hints and notes to assist you when called to this type of emergency. In this article, fireplaces and woodstoves are referred to as a “unit.”

The purpose of a chimney is to remove the by-products of combustion in the unit as well as to provide air flow for combustion. The movement of air for combustion and exhaust is called draft. This draft is created by warmer and, therefore, lighter air rising from the point of combustion and pulling cooler air into the unit.

The cause of most chimney fires is creosote, a by-product resulting from the incomplete combustion of wood. Creosote may be black or brown, crusty and flaky, tar-like, drippy, and sticky or shiny and hardened (photo 1). Often, all forms will occur in the chimney. Creosote accumulates on the side of the chimney and stovepipe as a liquid and later turns to a solid (photo 2). As it builds up, it not only blocks the flue but can ignite into a roaring fire. A fire hazard exists if one-quarter inch of creosote (or more) coats the inner walls of the chimney.


1. Photos by Jonathan Riffe.

 


2.

The first indication of a chimney fire is usually the noise—a roaring sound that grows louder as the fire intensifies. It may sound like a low-flying aircraft or a freight train and reach a temperature of up to 2,000°F. This roaring fire produces turbulence and pressure from the increased rate of combustion. Both may cause hot gases to be pushed out of cracks in the mortar (a cause of dwelling fires) or cause connectors to fall apart. Outside the house, you will see clouds of black smoke and sparks exiting the top of the chimney; in severe fires, flames can extend several feet above the chimney. However, there have also been chimney fires that homeowners did not know about. Slow-burning fires do not get enough air or have enough fuel to be dramatic or visible. But the temperatures they reach are very high and can cause as much damage to the chimney structure and nearby combustible parts of the house as the more spectacular ones.

Every piece of apparatus should have a chimney kit. Most departments carry this equipment in a metal bucket for easy storage and movement. The basic equipment should be the chimney bucket, a mirror (for a better view of the chimney interior), heat gloves, a weighted chain (with window weight, a spring, etc.), and chimney bombs (zipper seal bags containing dry chemical extinguisher powder) (photo 3).


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FIREFIGHTING OPERATIONS

On confirmation that there is a working chimney fire, institute the following action plan.

Interior Sector

1. Advance your hoseline (1½- or 1¾-inch) to the front of the residence. Remember: If you lay out, you are pulling an attack line (photo 4).


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2. Determine the status of the occupants of the building.

3. As soon as the occupants are determined to be safe, go directly to the attic and make sure that the fire has not extended into this space or the cockloft (photo 5). The older a chimney, the more susceptible it is to deterioration. As the chimney ages, the mortar between the bricks begins to fall out. This creates space between the bricks, which can easily cause the fire to spread to the attic and wall spaces. However, masonry chimneys are not the only ones to watch for fire spread. New chimneys or “factory-built chimneys” may present problems as well. Some of these require unrestricted air flow to keep the metal cool enough not to present a fire hazard. The buildup of creosote may restrict that flow. Others may not have been installed with enough clearance. This clearance may not be a problem during normal operation. However during a chimney fire, with its increase in temperature, the reduced clearance may cause the structure to become involved.


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4. Investigate the full length of the chimney to guarantee the fire has not extended into any walls surrounding the chimney. Use a thermal imaging camera and heat gun on each floor of the house.

5. Examine all walls for closed-off thimbles (openings through which a stovepipe passes) behind wallpaper, paneling, etc.

6. Check the carbon monoxide readings in the house with the carbon monoxide detector.

7. Place floor runners from the doorway to the unit and, if possible, around the unit to keep the homeowner’s floor clean (photo 6).


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8. Unload the wood from the unit, place it in the salvage bucket, and unload outside the residence (photo 7). Continue to do this until all of the wood and hot ashes have been emptied from the unit. Unload the bucket outside of the residence, and wet down with a hose or pressurized water can (photo 8). Make sure the wood and hot ashes are no longer burning. You don’t want the woods or house to catch on fire after you leave.


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9. You may have to take apart the piping that extends from the unit to the chimney to get a visual inspection to see if there is any fire evident at the base (photo 9). Once you have emptied the unit and removed the piping and you can see inside of the chimney, you can now work with the Roof Sector.


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Roof Sector

1. Visually inspect the chimney with a mirror from the chimney bucket to determine the extent of the fire. Most chimney openings are covered with a chimney cap. You can easily remove it with hand tools (photo 10).


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2. If there is a fire in the chimney, it needs to be extinguished. This can be done with “chimney bombs” (small bags filled with dry chemical) or a fire extinguisher and the weighted chain. Drop the chimney bombs directly down the chimney until they hit the bottom. The impact and heat at the base of the chimney will cause the bag to burst; the normal air flow (draft) in a hot chimney will carry the powder up and extinguish the burning creosote. Keep in mind this may not yield the desired results if the chimney is severely clogged and not drafting properly. Do not open the bags and pour the powder down the chimney. This is ineffective.

There are also special nozzles you can insert into the chimney that give off a mist or a fog to extinguish the fire. Never use a hoseline; it will damage the chimney lining. The key is not to change the temperature in the chimney too quickly. Prefabricated chimneys have a problem with water—the combination of water, creosote, and fire can produce acids.

3. After you have dropped the first chimney bomb, you can then slowly lower the chain/weight down the chimney until it reaches the base (photo 11). A crew at the base of the chimney (where the woodstove or fireplace is) will notify you when the weight has reached the base. Once it has, vigorously spin the chain inside the chimney. This will cause the burning creosote to fall into the base of the chimney. Once that is completed, raise the chain. You may have to drop one or two additional bags into the chimney to extinguish the remainder of the fire.


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During the incident, make sure you are wearing complete personal protective equipment (PPE) and SCBA. Gloves and jacket are extremely important for the Roof Sector working the chain. Activate your SCBA if the heat, ashes, and soot become unbearable as the fire is being extinguished.

Once all of the above objectives have been completed, check the walls around the chimney and attic for the final time with the TIC or a heat gun. Remember to reseal the attic space. Recheck the carbon monoxide readings inside of the house because of the smoke that has permeated from the unit throughout the house.

Last but not least, remember that you are a professional organization and your performance is what separates you from other departments. Little things count. After you have completed everything, ask the homeowner if he has a vacuum or broom so you can clean up the mess around the unit. The homeowner is already pleased you extinguished the chimney fire. Vacuuming takes only five minutes, and what a difference it makes!

The chain and weight will probably be extremely hot, so use caution when placing them back in the bucket and on the apparatus (photo 12).


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•••

Is your department equipped, trained, and ready for this type of emergency? The standard wood burning stove and fireplace unit is quickly declining and being replaced with pellet stoves, gas stoves, and other types of units. However, it is imperative to be ready for these incidents. Also important: Remind homeowners that their chimneys should be professionally cleaned before they begin to use them for the season.

JONATHAN RIFFE is a firefighter at 30 Engine for the District of Columbia Fire and EMS Department and the chief of the Huntingtown (MD) Volunteer Fire Department. He has an A.A.S degree in fire science from the College of Southern Maryland and a B.S degree in fire science from the University of Maryland University College. He teaches firefighter training through the Maryland Fire and Rescue Institute and has assisted in teaching Mayday training throughout the country. He has several certifications, including firefighter II, fire officer IV, EMT-B, hazmat tech, and instructor III.

LARRY PATIN is a planner with the United States Capitol Police Hazardous Materials Response Team. He is the captain of the Huntingtown Volunteer Fire Department, where he also served nine years as chief. He has a B.S. degree in emergency health services management. He has been a Maryland Fire and Rescue Institute instructor for the past 18 years and also teaches at FDIC. He has a number of certifications, including EMT-P, fire officer II, fire instructor III, and hazmat technician.

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