A soot fire or chimney fire occurs when soot deposits in the chimney ignite. These flammable soot particles normally result from incomplete combustion of the fuel. In general, such fires occur when using solid fuels, in rare cases also with liquid and gaseous fuels.
The causes of the formation of such combustible deposits is usually operating errors of the operator. These deposits could also be manifested by the use of a fuel which is too moist or even unsuitable, a worn hearth or an excessive reduction in the supply air.
All these points mean that the temperature in the combustion chamber is too low and therefore not all combustible components can be burned. In very few cases, a technical defect of the fireplace could also be a reason.
Depending on the cause, the degree of fire also varies.
Flake-dust soot fire
In case of this fire, the soot deposits dissolve in the chimney and are discharged to the outside. The soot deposits can then be identified by strong sparks. Such soot fires endanger flammable components and neighbouring buildings.
Solution: Chimney sweeper cleans away the soot with a suitable sweeping tool.
Hard or shiny soot fire
These soot fires produce extremely high temperatures, which range around 1000 ° C. As a result of this heat, pitch, tar and glossy / hard-soot layers swell up to 30 to 50 times the volume and there is the danger of a chimney closure. In addition, the residues become liquid and can close the elbow points when the chimneys have offsets.
One can also expect a high risk of fire for anything flammable in the area, in addition to high flames and very strong sparks flying at the chimney top.
As a rule, a chimney fire is not extinguished because the combustible components can ignite again at any time. The chimney sweep ensures that it does not come to a chimney closure any time. The fire department ensures fire protection.
Solution: Chimney sweep constantly cleans/removes the swollen residue with a suitable sweeping tool.
It is important that a soot fire is never extinguished with water, as it creates huge amounts of water vapor, which leads to a strong pressure increase in the chimney and this can literally lead to an explosion!
If all requirements and standards are met, a soot fire should not occur!