A fire broke out at the base of a building’s wooden structural column, on the job site of a chemical plant undergoing renovation work. The outbreak of fire was detected during a 2nd security round, 4 hours after operations at the job site had stopped. Upon their arrival, the firemen disconnected the site’s electrical power supply then were able to bring the blaze under control after 30 minutes. None of the installations in operation were located near the fire; only a 10 m³ tank of acetic acid was in the immediate vicinity of the wall concerned.

The blaze was apparently caused by pipe welding operations being conducted on the wooden column by a subcontractor 4½ hours earlier. Incandescent particles or burning droplets may have fallen at the base of the column during the welding operations and then smouldered until finally catching fire. The accident only caused property damage: the wooden structure separating the two walls was destroyed, along with 10 m² of roof. The firefighting water was recovered in special catchpits designed for this purpose, then treated by the site’s treatment station.

Following the accident, the prevention and protection mechanisms were improved: monitoring at the end of the job site is now conducted by the site foreman and the plant’s delegated officer in charge; job site wastes are to be removed at the end of each work day. As an internal contingency plan had not yet been developed, the necessary information must be obtained from the fire department (description of stock contents, the site’s extinguishing capabilities, location of water sources…). Furthermore, the Inspectorate requested that the electrical installations be inspected by an approved organisation prior before the production equipment be placed back into operation.