Methods for implementing the safety study of industrial activities with majoraccident hazards. Simulation of diffusion of dangerous substances for the risk evaluation Stefano SAETTA, Daria PINOTTI Dipartimento di Ingegneria Industriale, Università di Perugia, Perugia - Italy email: stefano.saetta@unipg.it Luca PROIETTI ARPA Umbria, Perugia KEYWORDS Safety Plants, Disease simulation, hazard prevention ABSTRACT In the paper a case of study of security is made. Case can refer to a real situation where this study is compulsory by law (Council Directive 96/82/EC). For privacy reason any specific reference to case considered has been omitted. Procedure by which implementing this analysis are shown. Estimation of possible initial events and their probability of happening are made. By using a simulation software the potential impact of a disease has been evaluated, by investingating the possible area involved. Useful insight for further simulation are made. INTRODUCTION In the paper an analytical safety study in made. Any reference of real cases for privacy reasons have been omitted. Generally speaking case refers to the facility of high toxic substances storage. As known [1], this activity must comply with the European Council Directive 96/82/EC, where industrial activities with major accident hazard are considered. While the studies of safety in this case are well known, the issue of safety is always very important considering also recent accidents (Toulouse, Baia Mare and Enschede). Today there are simulation tools that could help in making the studies. With better simulators and with the possibility offered by, for instance, Virtual Reality, it is more and more possible to “try in advance” possible dangerous situations before they can happen. evaluation tools. In addition, taking a look outside Europe, the tumultuous industrial development that is happening in different areas of the world is an interesting field of application of this studies. An other recent aspect connected to the major accident hazard activity is to include also security issues. In the first part of the paper basilar procedures and rules for making the analysis are shown. A particular stress is pointed out in considering historic documentation to make this study. Afterwards an industrial plant in considered with the estimation of initial events with their probability to happen. Also results of the simulation of the diffusion of the dangerous substance are shown. This is useful for evaluating the potential risk. Finally further considerations about the useful use of other simulation tools are made. TOOLS USED IN MAKING THE ANALYSIS As known hazard analysis of major accident industrial activities developed in Europe after some major accidents events such the dioxins emissions from a factory located in Seveso, Italy .Since then the European directive “Seveso” has been first introduced with EC/501/1982 and in the following modified with Council Directive 96/82/EC (Seveso 2, implemented in Italy in 1999). The main aim of legislation is to prevent major accident from dangerous substances used in industrial activity. One of the peculiar point is that, in the hazard evaluation, to consider all possible combination of minor accidents that can cause a major accident. In many case, hopefully, the analyst must consider situations that never .....