Summary of Unconfined Vapour Cloud Explosions

'SUMMARY OF THE EXPLOSIONS OF UNCONFINED VAPOUR CLOUDS
From </ref> Gugan monograph on te nature of UCVEs, the realisation of the severity and extent of te damage from their detonation has steadiy grown. Starting from the classical investigation by </ref> Zel'dovich, Kogarko and Simonov of small scale spherical detonations, they were soon expanded to varying mixtures of fuel and oxidant and the effects of inert diluents </refs> Bull and co-workers and Kogarko and others. However, many features remain to be resolved in the generation of the blast wave in the surrounding atmosphere which produces as much or more damage than than that produced within the cloud itself. Amongst these are the effects of the likely variation in composition throughout the cloud </ref> Nettleton, the influence of structures on the acceleration of the initiating flame </ref> Nettleton and the type and strength of the initiator </ref> Nettleton.

LIST OF INCIDENTS
</ref/> Strelow was one of the first to review spherical detonations. Many more have occurred since then, some in cases, discussed later, where external confinement played a minimal role. That in Flixborough in 1974 </ref> HSE Report, recently subject to criticisms, see </ref> Cox, drew them to the attention of the UK public. It was followed by one in the Delaware Oil Refinery in 2001, </ref> US Department of Justice. In the same year another occurred at the Humber Refinery (UK), </ref> HSE Report. The UK has proved particularly susceptible with that, probably causing the greatest number of casualties, at the Piper Alpha North Sea rig of a fire and explosion </ref> McGinty. Then, shortly after British Petroleum's take-over, there was a UCVE at the Texas City Refinery, </ref> Chemical Safety and Hazard Board. The explosion at Buncefield oil depot </ref>, with a blast wave that wakened those within a 200 km. radius, was hopefully the last in the UK. More recent (2007 and 2009) and poorly documented ones, in Makali and the shopping complex in Catano, both in the Phillipines, have presented investigators with problems in deciding whether some of the damage might have been caused by a terrorist act.
Explosions where containment, until its final stages, played a minor role include those in the unloading/ cleaning of the tanks of giant oil carriers, see 1979 Betelgeuse in Eire, 1987, Vitoria in Seine, 1989, Khark V in Morocco, 1990, Mega Borg in Galveston and 1991, Haven in Genoa summarised by </ref> Bergman and Reigel. </ref> Oppenheim suggested that a UCVE, involving hydrogen and air, occurred following melt-down of the nuclear reactor at Three Mile Island.
EXTENT OF DAMAGE AND MEASURES OF MITIGATION.
</ref>Leiber gives a comprehensive list of blast damage produced by various accidental explosions. Few produce symmetrical patterns of damage anticipated from spherically expanding fronts. </ref>Sadee, Samuels and O'Brien suggest that it may be accounted for by the influence of non-symmetrical siting of obstructions both on the acceleration of the flame and the resultant blast. The influence of inerting the tanks of crude oil carriers is demonstrated by their markedly increased record of safety. Quenching of the flame by water sprays has had many advocates, see for instance </ref>Watts or Thomas. </ref>Nettleton has demonstrated how the intensity of the blast may be reduced by triggering the release of a gas with a higher velocity of sound.

SEE ALSO
Buncefield Fire
Flixborough Disaster
Lincolnshire Fire and Rescue Service
Detonation
Deflagration
Blast Wave
Flame Retardants
REFERENCES
*Gugan, 'Unconfined Vapour Cloud Explosions' UK Inst.Chem.Eng., (1979).
*Zel'dovich, Kogarko and Simonov, Sov.Phys.Tech.Phys.,1,1689 (1956).
*Bull, Elsworth, Hooper and Quinn, J.Phys.D.,9,1991,(1976).
*Bull, Elsworth and Hooper, Acta Astronautica, 5,997 (1978).
*Kogarko, Adushkin and Lyamin, Int.Chem.Eng., 6, 393 (1966).
*Nettleton, J.Occ.Acc., 1,3, (1976) and arch.termo.i spanalia, 8,2 (1977).
*Nettleton, Comb.Inst.European Symp. p72, Academic Press, London, (1973) and arch.termo.i spanalia, 6,457 (1975).
*Nettleton, 'Gaseous Detonations', Chapman and Hall, London (1987).
*Strehlow, 14th.Symp.(Int.)Comb., 1189, Comb.Inst., Pittsburg, (1973)
*HSE Report, HMSO ISBN 0113610750.
*Cox, Chem.Engineer No.309,353, (1976).
*US Dept. Justice Law Suit, (2005).
*HSE Rept. on Conocophillips fire and explosion, (2003).
*McGuinty, 'Fire in the Night: The Piper Alpha Disaster' Macmillan, London (2008).
*Chemical Safety and Hazard Investigation Report No.2005-044-TX, (2007).
*Bergman and Riegel, Plant/Operation 2,189 (1983).
*Oppenheim, Appendix C, Technical aspects of hydrogen control and combustion in light-water reactor accidents, Nat.Acad.Press, Washington, 109 (1987).
*Leiber, 'Assessment of Safety and Risk with a Microscopical Model of Detonation', Elsevier (2003).
*Sadee, Samuels and O'Brien, J.Occ.Acc.,1,203 (1977).
*Watts, J.Loss Prev.,10,48 (1976).
*Thomas, UK Inst.Chem.Eng.,78,339 (2000).
*Nettleton, 2nd.European Comb.Symp., Orleans (1975)>
Michael Nettleton (talk) 15:33, 6 February 2010 (UTC)

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