Dynamic Simulation Of Industrial Accidents Davide Manca, Sara Brambilla CMIC Department, Politecnico di Milano P.zza Leonardo da Vinci, 32 – 20133 Milano – ITALY – davide.manca@polimi.it In the past, process simulators and accident simulators belonged to two distinct worlds. Dynamic process simulators were mainly applied to process control, process dynamic investigation and safety analysis (in terms of definition of emergency shutdown procedures). Accident simulators were related usually to the steady state accident investigation, as well as risk analysis and emergency preparedness and response. The manuscript shows how the coupling of process and accident simulators represents an innovative and powerful tool to support the engineer’s activity in several fields, e.g. process planning, process control, accident investigation, accident preparedness and response. The biunique interaction between these simulators allows investigating feedbacks and interactions among plants and industrial accidents. Actually, process dynamics affects the source term, i.e. the amount of released components and their chemical and physical properties, while the accident dynamics closes the loop by affecting the plant dynamics. The accident may have a direct effect on the plant dynamics (as in the presence of a heat source, e.g. a pool fire) or may have an indirect effect by influencing the integrity of field operators when the release of a toxic substance occurs. The manuscript shows the biunique interactions between a pool fire (originated by the release of a flammable liquid, as the consequence of an industrial accident) and the process itself. 1. Introduction Dynamic process simulation has become an indispensable and central tool for process design, analysis, and operation in the chemical industry. The dynamic simulation of a chemical process is a step ahead from the steady state analysis and has some effective and significant advantages. A dynamic simulation of the process allows: checking the control system configurations before applying it to the real plant so as to uncover possible control system errors; training the operators to increase their awareness and skills; planning and testing the start-up and shutdown procedures; increasing the process safety by testing and validating the procedures in a non-destructive environment. The support of a dynamic process simulator to training allows operators gaining experience, facing malfunctions and deviations from the nominal conditions, and becoming aware of the importance of following the correct procedures. The operators can modify virtually the process variables of the dynamic simulation while quantifying the consequences on the plant conditions without incurring into real risks. Moreover, the operators are trained to cope with plant deviations from nominal conditions due to accidental events that affect either the plant (e.g. emission, release, fire, explosion) or the people working in the plant (e.g. a fire, explosion, toxic gas cloud). Industrial accidents are dynamic phenomena that evolve depending on the