RR1129 - Buncefield investigation: dispersion of the vapour cloud

The Buncefield explosion on 11th December 2005 resulted in widespread damage to the surrounding area and huge fires involving large oil fuel tanks. Liquid petrol, released from a large storage tank that overfilled, formed a dense, low-lying vapour cloud that spread across the site and neighbouring areas before igniting. Following the incident, HSE sponsored a large programme of experimental and modelling research to investigate the technical issues involved and develop methods of analysis. Previous HSE Research Reports (RR718, RR908 and RR936) described research on the explosion event, vapour cloud formation, and liquid flow.

This report examines the dispersion of the flammable vapour cloud. Images of the visible mist from security camera records are analysed and Computational Fluid Dynamics (CFD) simulations of dense gas dispersion are presented and compared to observations including burn damage. The modelling showed that the vapour cloud dispersion behaviour under zero wind speed conditions is affected significantly by terrain and obstacles. A paper on these findings was published in 2011 (Gant and Atkinson, Process Safety and Environmental Protection, Vol. 89(6).) This detailed report, prepared in 2008, gives full details of the modelling that are of ongoing interest for scientific specialists working to further develop understanding of vapour cloud explosions and their mitigation.

A 2016 review by HSE specialists of vapour cloud explosion incidents worldwide is described in RR1113.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

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Updated 2021-12-14