3. Assessment of the overpressure effects of a BLEVE 3.1 Phenomena involved The problem of determining the overpressure effects of a BLEVE covers several different issues. The overpressure effects of a BLEVE can in fact be generated by three different, non-exclusive phenomena: gas phase expansion ; explosive vaporization of the liquid; combustion of flammable vapors. Thus, a typical overpressure signal from a BLEVE may be as shown in figure 9. The relative intensity of the peaks in the figure is not representative.