At 2:50 pm., a tube burst in the preheating furnace of the desulphurising section of a refinery resulted in the release of a mixture of gasoil and hydrogen (40 bar) that provoked a large fire.

One operator was at work in the section. After detecting the fire start in the furnace, the evacuation of the area was started. A second operator arrived at the scene, presumably for the change of shift. At 2.55 pm., a large fire burst due to the collapse of the tube, injuring seriously the 2 employees. One of them died in hospital the next morning.

The fire department first responded by cooling adjacent installations ; the large amount of water used caused the sewer to overflow. The material loss was estimated at 500.000 euro (excluding the production losses during the following 6 months stop).

The tube rupture was due to a high temperature sulphur corrosion caused by negligent maintenance in combination with strong internal pollution in the convection tube. The maintenance management was indeed inadequate and the replacement of pressurised parts not documented : the return bends of the involved convection tube had been replaced in 1997, but not the straight pipe itself which was 37 years old.

The seriousness of the situation was not recognised when the first signs of the incident were visible. The emergency procedure in case of fire in the furnace asked the technicians to close valves underneath the furnace, which means getting closer to the risks…

The operator improved maintenance and documentation with structural inspection management and inspection techniques and/or preventive replacement of parts of a certain age. Working procedures were also improved and a shut down from safe distance was installed.