22.1 INTRODUCTION

Boiling liquid expanding vapor explosions (BLEVEs) are one of the most severe accidents that can occur in the process industry or in the transportation of hazardous materials. Strictly speaking, these explosions do not necessarily imply thermal effects. However, in most cases the substance involved is a fuel that causes a severe fireball after the explosion. Usually BLEVE refers to the combination of these two phenomena, BLEVE and fireball, i.e., to an accident simultaneously involving mechanical and thermal effects.

BLEVEs occur with a certain frequency: the substances that can lead to them (butane, propane, vinyl chloride, chlorine, etc.) are relatively common in the industry, as well as the installations in which they can happen (tanks and tank cars). They can have diverse origins, such as runaway reactions and collisions, but the most frequent one is the action of fire on a container. Table 22.1 (Prugh, 1991) shows a list of the most significant BLEVEs that have occurred between 1926 and 1986. As can be seen, most of these involved fatalities. Another source (Londiche and Guillemet, 1991) mentions 900 fatalities and over 9,000 injured in 77 BLEVEs occurring between 1941 and 1990.