Two Types of Chimney Fires Explained

Chimney Fire
In prefabricated chimneys, a chimney fire will warp the flue system and the cap, as pictured.

A lot of people don’t know it but not all chimney fires are the same, that is, professionals classify chimney fires into two different classes based on differences between the two, and both are generally covered by homeowner’s insurance. You will want to check with your insurance agent to be sure that you are protected against both. The difference between the two is the way the fire actually burns.

A rapid burning chimney fire is the type of chimney fire which your chimney professional will usually detail to you. An rapid burning chimney fire can be characterized by a loud rushing or rumbling sound which can resemble the noise of a nearby freight train. Insurance agents refer to chimney fires as sudden occurrences.

Chimney fires are caused by creosote buildup in the flue system which is ignited by sparks from the flames below.

Chimney Fire
This cap was warped by a chimney fire in a clay flue system.

The rapid increase in temperature in the flue system caused by combustion can cause physical damage to the flue system in the form of cracking the flue tiles or even causing them to crumble. These types of chimney fires generally leave behind glazed creosote all over the flue system because combustion actually occurs in the flue system and the creosote is what is being burned.

A slow burning chimney fire occurs when the heat from the flames in your firebox, which is intended to contain such heat, makes their way up through the damper system into the chimney flue system. These chimney fires burn slowly due to lack of oxygen.

When certain conditions exist, the flames move up through the damper system from the firebox, causing an extreme change in temperature in the flue system known as thermal shock. This thermal shock can damage the flue tiles by cracking or crumbling the flue tiles which are not meant to contain such levels of heat. In slow or rapid burning chimney fires, sometimes the chimney’s flue system is completely cleaned so that it looks like new. This is not typical but can be the result of a chimney fire.

Clay Lamb
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2 thoughts on “Two Types of Chimney Fires Explained

  1. My name is Wesley Muir, I’m 28 and have been with my fiancé for 8 years. We have a 3yo and a 6wk old. Our house recently burnt down. I have a story with lots of pictures I would like to share with you to help me determine if I am responsible for taking my families home, their security, their comfort, and our dog.
    I know that sounds harsh but I feel it necessary I understand the consequences of my ignorance and take ownership of my mistakes.
    I will tell you, in my unprofessional opinion the burn pattern along with the environmentals, events and pictures do not show me evidence of a chimney fire. I would like to point out the keyword “unprofessional”.
    I feel crazy and I can’t tell if my mind is just trying to reach out an find justifications to ease my hearts guilt or if my heart is refusing to accept responsibility and is is trying to convince my mind why.
    Sorry I sound crazy but your response and help in anyway would be sincerely heartfelt appreciated which ever direction the responsibility falls.
    Wesley R. Muir

  2. After speaking with you, on the telephone yesterday, I felt it important to respond to your blog post.
    Please note that I have removed your personal phone number from this post!
    May I first rejoice with you that you and your family where not hurt in house fire, while at same time express my sincerest regards for the lose of your families dog.
    Your sending me pictures, to provide you with my own opinion of a matter of this magnitude while not actually being able to be physically on your property, I feel that it would not be prudent or professional on my behalf.
    Respectfully may I say that I’m not a Forensic Fire Investigator, nor do attempt to act in that manor. It is my opinion that professional fire investigators needs to be supplying you this very critical information, as well as their own written legal opinion of the “cause of” the fire that has occurred at your home.
    I will assume that a insurance carrier as well as a fire investigator will be doing this type of investigation before payment for any claims to you or possible a landlord are satisfied.
    My concern is the sorrow and guilt that I hear in your words. Please allow me the liberty to share my own Biblical perspective. After the death of King David’s son, that he personally knew that he alone had bought on, he needed to grieve for a very important period of time then move on.
    For me a period of grieving as well as having closure is an important part of our healing process. If I hadn’t gone through periods of grieving in past events in my own life I would not be able to function or lead my own family with the love and attention that is needed.
    I found that grieving, healing as well as fact finding, all go hand in hand then I had to make a choice to move on, or not. I had to learnto identify what part of this process I was in, as well as the amount of my own life and timethat I would allow myself spend in it!
    . . .During what ever part of the process your in, may you receive God’s blessing and protection on you and your family!
    Clay Lamb

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