Abstract Fire risk in Architectural Heritage represents a fundamental problem for occupants’ safety. Italian-style historical theatres are one of the most interesting examples because of their historic and artistic value, high fire vulnerability, fire sources and occupants’ features (many people are not familiar with the architectural spaces). Current fire safety regulations approaches for similar Architectural Heritage generally suggest massive and irreversible interventions in order to improve the occupants’ level of safety: main related solutions concern with interventions on building layout (e.g. introduction of fire-proof elements; increasing dimension and number of evacuation paths and exits). This really implies a conflict in preserving original architectural characteristics. Besides, experiments demonstrate how these adopted solutions can be insufficient in improving the individuals’ safety level, especially in case of high occupants’ density and people who are unfamiliar with the building itself, because of individuals’ behaviours in emergency conditions. An efficient emergency evacuation layout has to be able to help evacuating occupants, especially in smoke or blackout conditions. “Intelligent Evacuation Guidance Systems” (IEGS) could monitor human behaviours (how people move) and related criticisms in the evacuation process (e.g. slowing down along paths, paths blockage). Then, they could elaborate these data through smart inducing algorithm so as to suggest dynamic evacuation paths to occupants. In this way, IEGS can effectively suggest the “best” evacuation path to occupants depending on the effective human behaviours. In this paper, an IEGS is firstly defined by introducing suggested low impact environmental components and their related requirements. In particular, occupants’ behaviours are associated to evacuees’ density along egress paths, doors and exits, by using indoor individuals’ tracking systems (e.g. RFID, Wireless localization). A density-based algorithm based on Level-of-Service conditions is adopted for evaluating possible overcrowding phenomena and identify the best evacuation paths. Directional electrically-illumined signs are used so as to indicate the proper direction to occupants. Wireless communication between the system elements is required. Each element is provided with backup power supply. Then, the proposed IEGS is evaluated by applying it to a significant case study (the “Gentile da Fabriano theatre” in Fabriano, AN). Interactions between occupants and IEGS are reproduced within a validated fire evacuation simulator (FDS + EVAC), and the system effectiveness is evaluated by performing evacuation simulation for the whole building. Comparisons of evacuation times between the original scenario and the IEGS-related one are proposed. Total maximum egress time is reduced down to 26% in the IEGS scenario (40% for levels with 3 or more different possible paths). The number of people using secondary paths (that are also the less crowded ones) raises to 88%. IEGS elements correctly and fully interact with people by understanding their evacuation behaviour and suggesting them the most appropriate (clearest) path: hence, the overall evacuation efficiency can be so increased by virtue of this “behavioural design” approach. Besides, it is strongly important to underline how IEGS elements provide no architectural modifications.