Electrical Installations in Road Tunnel Design Criteria Tested by Fire Simulations: A Confirmation of the Zoning Approach

This article analyzes improvement criteria for the service continuity, design, construction, and verification of electrical systems in road tunnels. Fire prevention in road tunnels must satisfy the primary safety objectives relating to the safeguarding of people and the protection of assets against fire risks, complying with the sustainability criterion. With this goal, design parameters are identified as the temperature exposure levels (TELs) and necessary equipment qualification categories (EQCs) that characterize their thermal resilience and adequacy to severe environments. The primary objective is to guarantee the service continuity of electrical systems in ordinary operation and in emergency situations during and after a fire. Effective measures are to apply the zoning and layering criteria of roadway tunnels that suggest specific system topologies as a special “brush distribution” as confirmed by tests of fire simulations. Knowledge of these results can help to limit the feeling of uncontrolled panic in people who are in a tunnel during a fire event. A detailed analysis of the results can assist the operators of the intervention services in their decision making during rescue and extinguishing operations.