1, 2, 3 … Sweep !



The first waves of cold have arrived and along with them, the first light in the fireplaces… But to prevent a log fire from becoming a flue fire, it’s important to sweep chimneys according to the rules. This task should be completed at least twice a year, including once during the period when the fireplace will be used. According to DTU [Unified Technical Document] 24.1, “Sweeping means cleaning by direct mechanical action the interior of the chimney in order to remove soot and deposits and to ensure the flue is empty throughout”.


Chimney sweeps’ diagnostic duty

In reality, despite smoothly-running operations, unexpected fires still occur too frequently. The reason? Chimney sweeps have a tendency to omit their duty to diagnose visible non-compliance!

In other words, when they have a chimney sweep certification, craftspeople absolutely must reveal any anomalies in chimney flues, the most frequent being the presence of creosote.

Remember that creosote is residue from incomplete wood combustion that essentially forms when the smoke temperature is lower than 54°C. This tarry condensate fills the chimney and is protected by soot deposits. The problem is that creosote ignites at 145°C. So, at the beginning of winter, fireplace owners have their flues swept and start using their fireplaces, feeling they’re safe to us them. But when the soot is removed, the creosote ignites and we receive a claim.

Various types of claims

However, it’s important to be careful not to wrongly accuse chimney sweeps. Let’s specify that a residential fire that begins in the chimney area can have other causes, especially a non-visible defect like incorrect chimney installation.

Chimney flues or pipes, whether fixed or removable, used for evacuating combustion gases must be implemented in accordance with regulations. Among fire causes, we have identified:

  • More than 2 offsets, at 45° maximum (in other words, more than one non-vertical part)
  • Lack of expansion space at floor juncture
  • Incorrect safety distance between the external pipe and any adjacent combustible materials
  • Lack of a safety damper at each floor and ceiling juncture
  • Incorrectly interlocked flue (interlock must respect the flow of condensate)
  • Abrupt section changes, etc.

Regulations are strict in terms of constructing flues (rigid and flexible): The NF DTU 24.1 “Heating Engineering” is the normative reference document in this construction field. It establishes the regulations for designing and building chimneys, flues, and connecting pipes. It is crucial that flues are installed according to the rules and NF DTU 24 regulations.

Residential fires aren’t just caused by electrical faults. Let’s be careful and continue to verify chimney installations so that we can safely appreciate fires.

Construction Loss adjuster – GM Consultant Group

Nicolas PATRIS
Fire risks Loss adjuster – GM Consultant Group