Application of an innovative risk dedicated procedure for both conventional and 3D atmospheric dispersion models evaluation

In several contexts of risk assessment, prediction of safety distances is a key issue. Toxic or overpressure safety distances can be evaluated using both results from atmospheric 3D models (CFD, mass consistent, ...) and conventional approach results as Gaussian or integral models. Indeed, atmospheric dispersion of different types can be used in the same scope of application: hazardous materials, unobstructed environment, context of use (land use planning or emergency situation). In this context, the SAPHEDRA project offers an innovative dedicated evaluation procedure for hazardous phenomena consequence modelling tools to be used for risk assessment studies. The present paper describes the main steps of this procedure, the importance of defining the scope of application and the possible application to both above mentioned approaches with a view to increasing compatibility among atmospheric modelling evaluation. Based on a two-phase release example, which is much more complex than a gas release, this paper highligts different physics that both integral models and CFD tools evaluations have to adress to demonstrate the tools capability for a specific scenario