DISCLAIMER: For educational purposes only. If in any doubt always contact your local fire department for advice. In an emergency call 911.
When it comes to fire, safety is the number one priority. Fire is a great source of heat, however, it is also an incredibly destructive force, and such you should be aware of the risks and hazards involved with burning on a regular basis.
Today we will be breaking down one such potential hazard, the chimney fire.
What are the Causes of a Chimney Fire?
There are many factors that can cause a chimney to ignite. In the USA alone there are over 25,000 chimney fires annually, and such an event puts your entire house in immediate danger. Therefore, it is important that you understand what factors cause a chimney to catch fire.
One of the most common causes of chimney fire is improper fireplace size. If a fireplace is too large for a room it will be unable to volatize the fuel from the burning wood, and instead, this will travel up the chimney itself. This is an issue as having fuel collecting inside the chimney results in the burning of said fuel in the chimney at a later date.
Another contributor to the collection of fuel inside the chimney is moist wood. Wood must have a moisture content of below 17% to volatize effectively, otherwise, the damper parts of fuel will travel up the chimney in the same way as an unsuitable fireplace.
Finally smoldering over long periods of time can have a seriously detrimental effect on the health of your chimney breast. Overnight burns – if incorrectly prepared, can produce a lot of smoke and debris which has a high likelihood of getting stuck in the chimney – literally adding fuel to the impending fire.
What are the Signs of a Chimney Fire?
While understanding the cause of such fires is the most effective way of minimizing risk, you must also be aware of the signs that your chimney is currently on fire, ensuring you can act quickly and efficiently.
It is important to note that there are two types of chimney fires; slow, and fast-burning. As the name implies, fast-burning fires eat the fuel much quicker and as such, they produce a lot of smoke (from either end of the chimney), smell incredibly strong, and create a lot of noise.
The burning creosote stuck in the chimney creates a loud cracking and popping noise like a regular fire but much louder, and a loud roaring sound much like a large pyre or blowtorch, thanks to the large intake of oxygen at both ends.
Slow-burning chimney fires are much subtler because they are burning the creosote slower. However, there are signs of this occurring, such as structural damage at either end of the breast. This includes warped metal, cracked bricks, and tiles, or burnt objects near the chimney.
Slow-burning fires, while dangerous in the long run, are only identifiable after the fact. But the structural damage resulting from the fire can leave your chimney (and other parts of your house) in a dangerous condition.
If ever in any doubt always call 911 (or your own county’s fire emergency number)
What to do if a Chimney Goes on Fire?
So now you know what to look out for – what should you do once you spot it? Because there are two different speeds of burning, you should respond to them in two different ways.
A fast-burning fire is the most dangerous of the two. Fuel is burning at a rapid rate and the inside of your chimney is quickly heating up. As such you need to act quickly.
If you recognize any of the signs of a fast-burning chimney fire the most important step is to evacuate the premises and call the emergency services. By no means should you attempt to deal with your chimney yourself, as this could cause more damage, or even speed up the rate of burning.
Slow-burning chimney fires will need a professional chimney sweep to come and clean the chimney. Flammable substances on the inside of the flue become hot enough to catch fire but do not have enough oxygen to sustain them. Over time they can cause just as much damage as fast-burning chimney fires making it essential for annual maintenance. A clean flue is much less likely to catch fire as there will be no combustible material clinging to the inside.
How Often Should my Chimney be Cleaned?
While you can take steps during a fast-burning fire, a slow-burning chimney fire is relatively undetectable, and so the best method for minimizing the risk of either is through preventative methods.
While those who use their chimneys infrequently may not need to clean them as often, it is important you get a chimney inspection at a minimum annually. Regardless of whether you are a frequent burner or part-time fire-maker, chimneys are warm and sheltered spaces, so along with checking for any build-up of creosote, you must be wary of hibernating animals blocking the hole.
This inspection ensures your chimney is safe for operation, and as such the best time to get it inspected is when you are anticipating heavy use. This tends to be just before the burning season (spring to summer). Getting an inspection before fall will mean that you can fix any identified issues prior to the colder seasons.
Can you Clean your Chimney yourself?
Sometimes chimneys will turn up fine for use, other times there will be a build-up that needs clearing before you start burning again. If that is the case, then you may be wondering whether you might be able to save yourself some money and clean it yourself.
The answer is no. While there may be ways you can inspect and clean your own chimney, fire is not an element you want to mess with, and as such, it is better to spend a bit extra to hire a certified inspector and cleaner.
Soot is a relatively simple removal, however, if there is a build-up of creosote, specialist tools and equipment will be required to ensure that it is fully dealt with. Failure to clean a chimney properly may leave potential for a chimney fire in the near future, and when your house and your life are on the line, it is very much better safe than sorry.
A chimney sweep will cost you between $88 – $162 depending on the state of your chimney, and the chimney sweep’s own rate. While this may seem like a large sum to fork out annually, the expense of rebuilding a house will run you a much higher sum, and so this price tag is an unfortunate but incredibly necessary operational cost.
By now you should be better informed as to what a chimney fire is, how to spot it, how to respond, and ways you can prevent it. From natural build-up to burning incorrect material, there are many reasons a chimney may begin to accumulate creosote, but there are other ways you can prevent this from happening.
One of the best ways is to know what you can and can’t burn, and if you are unsure what you can safely put on your fire, you should check out our article ‘Can you Burn Wood with Nails in it?’.