(65bl) Simple Objects As Indicator of the Severity of Vapour Cloud Explosions

Simple objects such as instrument boxes and oil drums are often found on petro-chemical plant sites.  In the event of an accidental vapour cloud explosion (VCE),  they serve as reliable indicators of the explosion overpressure at their positions provided there is a good understanding of their behaviour in a VCE.  

Such objects were used to great effect in estimating the overpressure magnitude in the Buncefield incident in 2005. In large scale tests conducted since the Buncefield incident (both as part of a joint industry project and subsequently), such objects were located at varying distances from the cloud, as well as some within the cloud. Overpressure measurements were made at or adjacent to the location of these objects and many have been analysed using advanced finite element analysis. The objectives were to (i) gain a better insight into the response of these objects when subjected to different types and magnitudes of pressure loading, (ii) validate finite element models; (iii) assess the suitability of different finite element modelling techniques for predicting the response of these structures and (iv) develop pressure impulse (PI) diagrams which can be used to provide a rapid assessment of explosion magnitude through an examination of the damage level.

This paper presents an overview of the tests performed and the analysis results with comparisons with the actual behaviour of the objects.