Fires and accidents pose dire threats in underwater tunnels, due to the higher gradient, limited and difficult access, and egress. The issue of fire safety in road tunnels, especially in cold climate is exacerbated due to icy/slippery road conditions. At low temperatures, for instance, leaks forms ice that will affect traction and, can be an underlying cause of accidents. This requires a holistic approach to fire safety by considering the peculiar characteristics of cold operating environment.
The central thrust of this paper is to examine the current fire safety regulations and, requirements for underwater tunnels, by means of a case study. The goal is to assess the impact of cold operating environment, while also accounting for both foreseen and unforeseen uncertainties in the long term. The case study results demonstrate that implementing security systems and, equipment that have a better resistance to cold climate proves to be very important factor in reducing the casualties and lengthy disruptions of the transport system. Further, the results from the case study can serve as a guide in developing cost-effective and efficient evacuation plans that determines the best way to undertake evacuation activity in cold environment.
The issue of fire safety in road tunnels has gained high visibility, in recent years, following a series of dramatic incidents and fires, which led to human casualties, major structural damages, and lengthy disruptions of the transport system with hard felt impact on regional economies (Melbye and Dimmock 2006). In addition, road tunnel, especially underwater tunnel fire safety usually involves high uncertainty and high-stakes decisions (Gehandler 2015). Underwater tunnels, for instance, are substantially overrepresented in the statistics of fires in Norwegian road tunnels. In numbers, underwater tunnels constitute less than 4% of road tunnels in Norway; however, they represent about 44% of the fires and, the instances of smoke without fire in the period 2008–2011(Naevestad and Meyer 2012). The issue of tunnel fire safety is of high significance to Norway, since the country has one of the highest averages of road tunnel kilometres per inhabitant in Europe, with 844 tunnels and a total length of 768 km. In addition, 390 of these tunnels are longer than 500 m, some of which are among the longest in the world (24.5 km for the Laerdal tunnel, located in Aurland, Western Norway).