METHODS FOR VAPOR CLOUD EXPLOSION BLAST MODELING

The potential explosion hazard of fuels is quantified by methods in wh ich the explosive potential of a flammable fuel air mixture is express ed as an equivalent explosive charge whose blast characteristics are k nown. In this paper, the two most current methods are described and de monstrated in a simple case study. TNT-equivalency methods have been w idely used for this purpose for a long time now. Generally speaking, T NT-equivalency methods state a proportional relationship between the q uantity of fuel available and the weight of a TNT charge expressing th e cloud's explosive potential. However, fundamental and practical obje ctions are met if the TNT-equivalency concept is used for vapour cloud explosion hazard assessment. To some extent, these difficulties are r emedied in an alternative approach, the multi-energy method. In the mu lti-energy method, a flammable fuel air mixture is considered to be ex plosive only if it is in a partially confined, congested or obstructed area in the cloud. The explosive potential of the fuel air mixture in the various partially confined, congested or obstructed regions can b e expressed as a corresponding number of equivalent fuel air charges. The multi-energy concept is shown to be a flexible concept which makes it possible to incorporate current experimental data and advanced com putational methods into the procedure of vapour cloud explosion hazard analysis.