The Nature of Airblast Loads and Effects of a Process Cell Due to a Vapor Cloud Explosion

The accidental release of combustible materials is not an infrequent event in our highly industrialized society. Such a release has the potential to cause an associated explosion which can produce severe consequences to nearby workers, equipment and structures. This paper describes a computer program (HALL) which was developed for evaluating the consequences of internal accidental explosions on structures, equipment and people. This computer program was designed to help analyze the effects of blast waves which travel along a single axis, i.e., it analyzes one-dimensional propagation and reflections of blast waves within structures. In order for a HALL analysis to be sufficiently realisitic, the structure must be relatively long compared to its width. Structures or components of structures falling into this category include two- to three-story chemical process cells or hallways in process facilities. The program is illustrated by its application to a process cell which contains a chemical reactor vessel. The process cell is equipped with a blow-out panel and a blow-out wall. In this illustration the reactor vessel experiences a leak which produces a local vapor cloud which subsequently explodes. The solution focuses on the blast environment within the process cell and the response of the blow-out panel and a blow-out wall in mitigating the effects of the accidental blast.