Study on BIM-based simulation of fire emergency evacuation in college library

College libraries, as high-occupancy public spaces with complex layouts and atrium structures, face significant fire safety challenges, particularly regarding rapid smoke spread and safe evacuation. Existing studies often lack integrated simulations addressing both fire dynamics and human evacuation behavior in such settings. This study investigated the impact of the “chimney effect” in atrium libraries and fire source location on evacuation safety. Employing a multi-software coupling approach (BIM + PyroSim + Pathfinder), two fire scenarios were analyzed based on smoke visibility, carbon monoxide concentration, and temperature metrics. Results indicate that the atrium's “chimney effect” significantly accelerates hazard propagation: smoke spreads to the sixth floor within 300 seconds and reduces stairwell visibility to critical levels (<3 meters) within 612.5 seconds. Evacuation feasibility depends on fire location: a first-floor fire allows safe evacuation (ASET > RSET), while a third-floor fire causes hazardous congestion, reducing evacuation speed to 0.12 m/s. Simultaneously, integrating intelligent dynamic path planning, staircase widening (increasing capacity by 50%), and enhanced wayfinding signage can elevate movement speeds in congested zones from 0.12–0.24 m/s to 0.48–0.60 m/s, significantly improving evacuation outcomes. This research provides empirical support for enhancing fire safety in atrium-style buildings.