Scenario Based Fire Risk Assessment; The effects of longitudinal ventilation in case of fire in an existing road tunnel

Abstract

This study examines the effect of longitudinal ventilation in case of fire in an existing road tunnel. The purpose of fire ventilation in road tunnels is to control heat and smoke transfer. Large tunnel fires can be a major challenge for safe evacuation and emergency efforts, emphasizing the importance of fire safety measures in road tunnels. Hence, the study aimed to evaluate the effect of the longitudinal ventilation related to smoke control and tenable conditions. Fire simulations were conducted in FDS, which consisted of fire scenarios with rapid developing HGV-fires at 50 MW, 100 MW and 200 MW. Evacuation simulations was performed in Pathfinder. The work of the study indicates that the existing ventilation configuration could not prevent smoke from moving upstream. Furthermore, the results show that evacuees with reaction times ≤ 5 minutes did avoid exposure to toxicity levels above the acceptance criteria. However, acceptable visibility levels proved to be a challenge to maintain for all the fire scenarios. The author believes the findings of the study might provide valuable knowledge regarding the effect of longitudinal ventilation in the existing road tunnel in case of fire. Nonetheless, further research is recommended in order to validate the results in this study.