Firefighters intervened late in the morning today, Tuesday 18 June 2024, due to a chimney fire in Valgreghentino.
Chimney fire: intervention by the firefighters
The fire broke out around 12pm in a house located in an inaccessible area. Four teams from the provincial command of Lecco Lecco and the Valmadrera detachment intervened on site and used off-road vehicles equipped for fires in areas inaccessible to heavy vehicles.
The firefighters worked hard to get the better of the flames. The timely intervention avoided major damage to the structure.
The fire inside the chimney is due to the ignition of the soot deposited on the internal walls of the chimney. Soot is composed of unburned solid particles that are conveyed by the fumes and hot gases of combustion. The formation of these particles, which give smoke its characteristic blackish colour, occurs exclusively in the presence of solid and liquid fuels and must be excluded in the combustion of gases. The sulfur contained in some solid fuels, when burned, releases a certain quantity of sulfur dioxide in the fumes which, if condensed together with the water vapour, forms sulfuric acid, which is extremely corrosive. The formation of this acid film on the walls of the smoke ducts, in addition to being harmful to the materials, is also the cause of the aggregation of unburned solid particles and, therefore, of the formation of high quantities of soot which, exposed to the high temperatures of the smoke, in certain cases can catch fire.
According to the Fire Brigade, to avoid the formation of soot it is necessary:
ensure that combustion takes place in the presence of adequate ventilation, possibly with excess air so that all particles burn completely during the period they remain in the combustion chamber; in this regard it is essential to make sure that the ventilation openings required to allow correct combustion have been created;
carry out periodic cleaning of both the burner and the flue duct, in order to remove solid combustion residues;
avoid the formation of the flue adequately
avoid the formation of acid condensation by using sulphur-free fuels.
