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• Integration of ASET-RSET concept and FED concept into a risk index. • Map-based fire scenario design and fire risk evaluation design. • Incorporation of evacuation performance into fire risk evaluation. • Occupant weighted method for overall fire risk calculation. Fire is a critical threat to large buildings. With the fire smoke diffusion, the risk of injury and death exists over a wide area. To investigate the fire risk level of large buildings, a Risk Index is defined as the fractional effective dose at the moment of required safe egress time to model the maximum potential fire risk of an area. Then, the map-based method is adopted to acquire a Risk Index map for each fire scenario and a Risk Index scenario map for the whole building. Finally, the overall fire risk of a fire scenario and a building could be acquired by integrating the Risk Index in each area and the Risk Index scenario in each fire scenario. The platform of a subway station is taken as a case study to validate the applicability of the proposed method. The results indicate that the method provides a more detailed and accurate evaluation of fire risk distribution of each fire scenario and the whole platform. Besides, the proposed method can provide more flexible and adaptive evacuation strategy recommendations. The results could be used for future fire risk evaluation, worst fire scenario identification and evacuation strategy design in different buildings. [ABSTRACT FROM AUTHOR]

[Display omitted] • An improved Accimap framework is proposed for subway accident investigation. • A sub-system concept is introduced to model the multi-stage characteristics. • The internal logic of the Zhengzhou subway Line 5 waterlogging accident is analyzed. • The countermeasures taken by governments after the accident is summarized. The cause of major accidents provides valuable lessons for hazard prevention and management improvement. However, the investigation of major accidents in a social-technical system could be a challenge that requires inter-disciplinary approaches. Accimap, a system-oriented method in accident investigation, has been widely used around multiple industries. However, as a typical social-technical system with various internal and external interactions, system-oriented analysis has rarely been applied in subway systems. Therefore, the objective of this work is to enhance the Accimap framework to conduct a hierarchical investigation into the contributions of multiple factors to the Zhengzhou waterlogging accident and analyze the interconnections between factors during the accident's progression. To capture the multiple-stage characteristic of subway accidents, a sub-system concept is introduced. By studying the accident evolution in depot/construction subsystem, station/dispatch subsystem and tunnel/rescue subsystem, this work provides a detailed case study that reveals the underlying deficiencies in the emergency management of Chinese subway system. Besides, this work also reviewed the most important countermeasures and policies implemented by different levels of governments following the accident. By demonstrating the lessons learned from and improvements made after the major accident, the findings can support the accident prevention and policy making within the subway industry in the future. [ABSTRACT FROM AUTHOR]