The Gran Sasso National Laboratories (

The aim of this work is the application of a performance-based approach in the field of the Fire Safety Engineering within the Gran Sasso National Laboratories (LNGS), one of the structures owned and managed by the National Institute for Nuclear Physics (INFN). CFD (Computational Fluid Dynamics) models provide a solid foundation on which a complete assessment of the different choices and procedures of evacuation management might be performed. These choices take into account, not only the characteristics of the surrounding environment and the accident scenario, but also the psychological and human aspects induced in people involved in an emergency event. The analysis has been implemented through the development of fire simulation models FDS (Fire Dynamic Simulator of the NIST) applied to new experimental installations, facilities and utilities in one of the LNGS underground areas. The object of the study has been the definition and simulation of a fire caused by an electrical cabinet devoted to the new experimental apparatus named "LUNA-MV" located inside the interferometer tunnel of the LNGS. The analysis addressed the choices in the preliminary design of the safety systems and in the optimization of the technical, economic and design parameters taken into account for each hypothesized event scenario. The work allowed also identifying the crucial factors for reviewing and optimizing the LNGS Emergency Plan, thus providing useful elements to support the LNGS users' training.