At about 8 p.m., a fire broke out in the intake duct above a wood cutting machine. The fire spread to a 50 m³ cyclofilter used to collect wood dust in the maintenance area of a carpentry workshop subject to authorisation. The operator shut down the production line while the plant’s security team attempted to intervene, without success. The fire brigade was called and was able to put out the fire. The damage was insignificant and production was not affected by the incident.

The ignition source that caused the fire came from the cutting machines. The hot spot had spread into the wood dust extraction system. The fire detection and extinguishing system in the ducts was unable to operate because the operators in charge of locking out the system had not performed the tagout procedure following the technical shutdown that occurred on the day of the accident. The fire detection system was not slaved to the operation of the installations. Deficiencies in the training of these operators were found. The lack of regular cleaning of the suction duct had also participated in the formation of wood dust deposits that allowed the fire to spread. The failure to tagout the temperature detection system in the cyclofilter prevented rapid detection of the fire.

Following these observations, the operator:

• had the suction duct cleaned and integrated this cleaning operation into the list of monthly cleaning operations;
• provide specific training for the personnel in charge of lockout/tagout of the fire detection system;
• slaved the fire detection system to the operation of the installations;
• set up a dry riser inside all the cyclofilters.