Creosote Facts and How To Get Rid Of It
Creosote - What is it and How Can I get Rid of it?
By definition, creosote is simply unburned wood particles and condensed flue gases which deposit on the inside of the chimney. The creosote forms as the flue gases exit the fireplace or wood stove, and draft upward into the relatively cold flue where condensation occurs and begins to solidify. This results in carbon based condensation that materializes inside the flue and becomes creosote.
As creosote builds on the chimney interior, it goes through three stages and becomes more and more of a fire hazard as it goes through each stage. All three stages of creosote can exist in one chimney, and no matter if you have one or all three it's highly combustible. If allowed to build up in sufficient quantities, and ignite inside the chimney flue, the result is a volcanic chimney fire. This article discusses the three stages of creosote build up and which products are most effective to get rid of it before it causes damage to your property and family.
Stage 1 creosote build up is known as soot and is identified as fine, silky, black dust
Soot is primarily composed of unburned carbon particles but may also contain ash. Soot has a soft texture and will be black or brown in color. The flammability of soot will depend on the concentration of soot and ash. Soot, since it is made of carbon, is combustible. Ash is non-combustible.
Top Rated Products to get rid of stage 1 creosote
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Stage 2 creosote build up is known as creosote and is identified as porous and crunchy
Creosote can be defined as a combustible deposit in the venting system. Creosote is a by-product of incomplete combustion, which begins as condensed wood smoke including tar, fogs and vapors. If a fuel is fully burned there will be no smoke and, therefore, no creosote. Creosote will be hard brown or black and form either curly, flaky or bubbly deposits in the venting system all of which are flammable.
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Stage 3 creosote build up is known as glaze and can be identified as drippy, sticky, shiny glaze
Glaze is a form of deposit that presents itself as a shiny, tarry substance. Glaze can form puddles or drop down and make formations that resemble black icicles. Glaze is the densest type of chimney deposit and, therefore, represents the greatest amount of fuel to burn in the event of a chimney fire. Glaze is also the most difficult type of deposit to remove from the chimney.
Top Rated Products to get rid of stage 3 creosote
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What causes creosote build up?
Residence Time - Residence time is the time the smoke remains in the venting system. Residence time is affected mainly by flow. Flow is simply the amount of air moving through the chimney. Within certain limits, the greater the air movement, the lower the residence time will be. Abnormally high flow can result in turbulence, which can actually increase residence time. Low flow, usually caused by oversized flues, results in longer residence time and high rates of creosote buildup. The less time the smoke stays in the chimney, the less it can deposit on the walls. This is desirable for maintaining a clean chimney.
Smoke Density - Smoke density is the amount of smoke produced by the fire. When combustion air is restricted, it causes incomplete combustion resulting in high smoke density. Creosote is simply unburned particulates and gases leaving the fire. When smoke density is high, creosote deposits will be high. Without smoke there is no creosote. If you can visualize an open campfire, it generally produces very little smoke because it has plenty of air to complete the combustion process. With complete combustion there is no smoke and no creosote. Stack temperature is the temperature of the interior walls of the chimney. Stack temperature is affected by the amount of heat allowed to go up the chimney. The warmer the walls of the chimney the less the creosote can adhere to them. Stack temperature is also affected by the size and location of the chimney. If the chimney is on an exterior wall as opposed to an interior wall, it will constantly be subjected to outside cooling effects. If the chimney is oversized, it will require more heat to keep the surface walls warm due to the increased mass. With this thought in mind, you can see how a very large chimney that will never fully warm up would have the potential to cause excessive creosote deposits.
Prevent excess creosote build up and chimney fires by following these simple tips in our article for Proper Chimney Venting.