PUBLICATIONS AND VIDEOS

PROJECT SUMMARY

The Buncefield incident in December 2005 involved a large spill of petrol followed by a severe vapour cloud explosion that caused substantial damage to property and further loss of containment from nearby storage tanks. It also resulted in a major fire that took several days to extinguish. The Major Incident Investigation Board (MIIB) which was responsible for looking into the Buncefield incident invited explosion experts to advise on the work that would be required to explain the severity of the Buncefield explosion.

The Advisory Group carried out a preliminary assessment of forensic evidence and of results of supporting tests carried out by the Health and Safety Laboratory (HSL) but was not able in the time available to identify a single scenario that explained all aspects of the Buncefield explosion. A joint industry project, the Buncefield Explosion Mechanism Phase 1 JIP, was therefore undertaken (May 2008 to May 2009) to examine in greater detail the forensic evidence and perform further tests and analysis. It concluded that the most likely scenario was that an initial deflagration of the gas cloud (caused by a spark in the pump house) transitioned into a detonation when the flame travelled through dense vegetation adjoining the site. The project also recommended that further work should be undertaken to gain a better understanding of the dispersion and explosion characteristics of large vapour clouds, the influence of dense vegetation on the explosion development and whether an alternative mechanism to detonation might have played a part in the explosion.

The Buncefield Explosion Mechanism Phase 2 JIP commenced in July 2010 and was completed in December 2013. It involved several test programmes and analytical studies to understand how vapour clouds develop following large losses of primary containment, the characteristics of explosions involving large flat flammable vapour clouds and the key explosion mechanisms that can give rise to very high overpressures over a large area as observed in Buncefield and similar incidents.