In a chemical plant, a fire broke out on the roof deck of a blacking production workshop. The alert was given by the municipal police, in noting the presence of flames at the roof line of the workshop. The plant staff intervened using the site’s internal resources (fire hoses); the two casting sand production lines (resins and blacking) were shut down immediately and inerted with nitrogen. External emergency services arrived on the scene within 40 minutes of alarm activation and brought the situation under control after a 3-hour intervention. The press was informed by the operator.

Apart from the translucent roof panels, the rooftop of the workshop was untouched: only the electrical installations of the production unit were affected. The fire extinction water (10 m³ maximum according to operator) was collected in a pit beneath the workshop and disposed of as waste or discharged depending on its quality. No one was hurt, but six employees had to be temporarily made redundant.

The roof assembly was made from a fibre cement and composite thermal insulation, supported by a steel frame and consisting of a 50-mm layer of rock wool with an aluminium surface. The space between these two components appeared to favour the build-up of coal dust. According to the operator, spontaneous heating of this dust caused this fire, and the production installations were not to be blamed because the particle sizes involved in the process would not have been able to create explosive dust. Furthermore, no alarm was activated and the fire department found no signs of hot spots on the installation (55°C recorded at the cyclone with a warning temperature set at 80°C).

To reduce the likelihood of such an accident recurring, the operator planned on removing the rest of the isolating panels, so as to avoid the accumulation of dust.