At 11:30 a.m., an explosion occurred in a sawdust collection silo at a sawmill, igniting the silo’s bag filters. The firefighters were alerted by the employee who heard the detonation. They arrived at 12:30 p.m. and extinguished the fire at 7:00 p.m. The firewater was collected in a retention pond. The accident caused €225,000 in material damage and €111,000 in operating losses. The 17 t of wet sawdust from the silo were taken to an external composting facility.

The turbine of the sawdust collection system was abnormally worn. Sawdust was able to pass through the turbine and produce sparks. The sawdust collection system was fitted with a spark detection and extinguishing system designed to spray a jet of pressurised water. A spark caused the dust inside the silo to explode. It had been detected by the system, but was not sufficiently extinguished by it. As the system was designed to place the silo at positive pressure, there was a high concentration of dust inside the silo.

The dust suction fan is currently located upstream of the bag filter. The operator modified the system to prevent any further premature wear. He placed the fan at the bag filter’s outlet, thereby putting the system at negative pressure and reducing the concentration of dust inside the silo. The bag filter was moved away from the silo to prevent the spread of fire. The pressure of the nozzles on the spark extinguishing system was increased to increase their extinguishing efficiency. Other spark detection and extinguishing systems were fitted on the sawdust collection ducts. An outlet was also added so that sawdust is no longer sent to the silo if sparks are detected.