Simulation-Based Performance Analysis of Ventilation and Fire Protection Strategies in Road Tunnel Fires: Review

Tunnel fires pose severe risks due to confined geometry, limited evacuation options, and rapid smoke propagation. This literature review compiles insights from recent studies on smoke movement, ventilation control, fire suppression, and evacuation behaviour in tunnel environments. It also highlights the growing use of simulation tools like PyroSim and Pathfinder to analyse fire dynamics and human response. Key findings across studies include the significance of critical ventilation velocity, the risks of smoke back- layering, and the throttling effect in high-heat-release fires. While systems like water mist and deluge sprinklers improve tenability, their effectiveness depends on placement, droplet behaviour, and airflow interaction. Evacuation outcomes are shown to rely heavily on visibility, exit spacing, and guidance systems. The review underscores that tunnel safety requires a coordinated approach, where fire suppression, ventilation, and evacuation systems work in synergy. This paper aims to provide a more consolidated foundation for designing a more resilient tunnel fire safety system by thoroughly examining the tested strategies and simulation based evaluations.