This thesis investigates the impact of different fixed firefighting systems (FFFS) on road tunnel resilience. The road tunnel and fire protection communities are considering a uniform approach for considering the benefits of an integrated design for FFFS on other systems including emergency ventilation in tunnels. However, there is currently a knowledge gap in the evaluation of effectiveness and reliability of the integrated systems. This study provides a comprehensive synthesis of currently available information regarding the performance, effectiveness, reliability, and benefits of FFFS in road tunnel applications. It also helps to scrutinize different assumptions against the use of FFFS in tunnels. The investigation was based on publically available studies conducted in different countries for different types of FFFS in road tunnels. The FFFSs were analyzed for their impacts on heat release rate, temperature, smoke movement, ventilation load, fire spread, and structural damage. The analysis was followed by an annual economic loss analysis in the case of tunnel fire with and without FFFS. The study shows that the arguments against the use of FFFS were based on conceptions and were assisted with a failed experiment conducted in the Ofenegg Tunnel in Switzerland in 1965. There has been no FFFS malfunctioning or false activation experienced in Japan and Australia for over fifty years. Available full-scale tests, computational modeling studies, and surveys show that FFFS controlled the spread of fire, decrease peak heat release rate, and peak temperatures when compared to tunnel fires without FFFS. The cost benefit analysis for a tunnel fire with and without an FFFS showed that the tunnel can save a significant amount of money with the FFFS installed. The investigation recommends that a tunnel user should install an FFFS for structural safety. The data available to analyze the cost benefit, reliability, the impact on occupants, and the effectiveness on liquid pool fire is still limited. Further research is needed to address these issues.
