Systems approach to underground safety

The safety of underground traffic infrastructures can be considered from several viewpoints as a fairly mature field. Common minimum requirements for road tunnel safety were developed for all European countries in 2004. Furthermore, safety is codified in a detailed (at times even too detailed) manner, such as for road tunnels in several countries. Safety design can at times be extremely rigid and difficult for adapting to specific conditions, which in some cases may need to be more demanding than a “standard” tunnel. Other types of underground infrastructure, particularly, rail tunnels and underground industrial facilities, share a number of common safety-related issues with road tunnels, but are generally much less regulated. For example, there is no common regulation for the ventilation of rail tunnels in Europe. Various metro systems have different safety standards, in spite of having similar requirements. The present study illustrates selected aspects of a holistic approach required for achieving a high and sustainable safety level in underground infrastructure. Common aspects and differences between the various types of “conventional” and “emerging” underground infrastructure are outlined and the consequences are discussed, such as the different types of threats, widely differing probabilities of occurrence, and widely differing number of persons exposed. Different facilities require different safety systems; however, they can rely on common thinking and philosophies. It is essential for all stakeholders, ranging from operators and safety officers to fire services and administrative authorities, to grasp commonalities and differences to adapt requirements, regulations, and approaches to their specific needs.