Optimizing Key Evacuation Features for Safer Egress in Complex Buildings with Underground Connections: A Simulation-Based Approach to Resilient and Sustainable Design

This study explores the impact of key evacuation features on occupant safety in complex buildings with underground connections in Seoul, the city with the highest concentration of such buildings in the country. By analyzing factors like exit spacing, exit width, stairwell distances, and stairway configurations, the study assesses evacuation safety using fire and evacuation simulations, comparing available safe egress time (ASET) with required safe egress time (RSET). Reducing interior exit facility spacing from the legal standard of 100 m to 50 m improved evacuation time by 77.5% (from 36 min to 8 min and 7 s), with a further reduction to 40 m improving performance by an additional 23.3% (to 6 min and 13 s). In downward evacuations, reducing the walking distance to exterior exits from over 50 m to 30 m cut evacuation time by at least 59.9% (from 23 min and 55 s to 9 min and 35 s), ensuring successful evacuations. These findings demonstrate that optimizing evacuation routes, addressing bottlenecks, and improving evacuation feature standards can significantly enhance safety and minimize casualties. By adjusting building design and fire safety regulations, these optimizations promote resilient urban infrastructure, reduce disaster-related socio-economic impacts, and inform evidence-based policies, offering valuable insights for policymakers and guiding future improvements in fire safety and evacuation protocols.