Fire Safety Science Digital Archive

The main features of accidents with BLEVE's (Boiling Liquid Expanding Vapour Explosions), occuring in fires, are analyzed. Simple mathematical models, describing liquid or vapour discharge through perforations of vessels with superheated liquids and a liquid behaviour in heated by a fire vessel, are formulated. These models are verified on the basis of available in literature experimental data. The analysis of the well known accident with BLEVE on a railway tank in a fire and a fireball formation (Alma-Ata, 1989) is presented. It was shown, that this accident could be prevented by means of a vent device (safety valve or breaking diaphragm) with the cross-section area greater than 77 cm² and the operation pressure lower than 1.6 MPa. The using of such vent devices could prevent BLEVE's during fires with the presense of tanks with superheated liquids or liquefied gases.