Pollution
Humain
Environnement
Economique

An explosion took place in the smoke flue of a 2.5 MW gas boiler installed in the boiler room of a hospital. The accident resulted in significant material damage on the boiler (access doors and covers ripped out, masonry destroyed, joints and chimney interiors blown away). Two theories had been propounded as to the origin of the accident: malfunctioning of the burner cycle or more likely poor combustion and smoke evacuation conditions. The flue shape (large horizontal volume) and the presence of unfavourable weather conditions (storm) may have contributed to the accumulation of CO, with ignition of the other boiler connected to the same flue. Inspecting the gas solenoid valve helps ensure its air tightness.