A new method is presented to calculate the blast effects originating from an exploding vessel of liquefied gas. Adequate blast calculation requires full knowledge of the blast source characteristics, i.e., the release and consequent evaporation rate of the flashing liquid. As the conditions that allow explosive evaporation are not entirely clear and the evaporation rate of a flashing liquid is unknown, safe assumptions are the starting point in the modelling. The blast effects from a BLEVE are numerically computed by imposing the vapour pressure of a flashing liquid as boundary condition for the gas dynamics of expansion. The numerical modelling is quantitatively explored just for liquefied propane. In addition, it is demonstrated that often an estimate of BLEVE blast effects is possible with very simple acoustic volume source expressions.

The modelling shows that the rupture of a pressure vessel containing a liquefied gas in free space only develops a blast of significant strength if the vessel nearly instantaneously disintegrates. Even if a rupture and the consequent release and evaporation of a liquefied gas extend over just a short period of time, the blast effects are minor.