Chimneys and flue pipes must be swept at least every twelve months. The decrees mentioned in article L. 1311-2 may stipulate that chimney sweeping is to be carried out several times a year, including once during the heating period.
In the case of collective appliances, the flues are swept at least every six months, including once during the heating period. However, when a collective appliance is powered exclusively by gaseous fuels, flues that have never been used to evacuate the products of combustion of solid or liquid fuels or, once they have been swept prior to a change in the fuel used, that are no longer used to evacuate such products, may only be swept every twelve months.
In the case of first-time installation or replacement, the first sweeping is carried out within the period mentioned, depending on the appliance concerned, in the first paragraph or the first sentence or the second sentence of the second paragraph, following the first installation or replacement.
For the appliances mentioned in the first subparagraph and the second sentence of the second subparagraph, if they are not used at all for at least twelve months, no soot sweeping is required during this period. At the end of such a period, a sweep is required before any new use.
For the appliances mentioned in the first sentence of the second paragraph, if they have not been used at all for at least six months, no soot removal is required during this period. At the end of this period, a sweep is required before any new use.