Tunnel Safety

Aerodynamics and Smoke Propagation

Tunnel safety is affected by many factors. Among these, the conservation of smoke-free escape routes is of paramount importance in case of a fire incident. Tunnels, their cross passages, escape tunnels or emergency stair cases form complex confined air spaces. Counteracting forces like wind pressure or heat-generated buoyancy have the potential to turn around the anticipated movements of fresh air and to allow smoke entering and blocking escape routes and in that way reducing the safety. Clearly a task for the specialist.

Probability, Loss and Risk

For road tunnel projects, our experts conduct comprehensive quantitative risk assessment and risk analysis studies according to the methodologies of PIARC, RABT, RVS, ASTRA or ANAS in order to find the optimum ventilation design in consideration of tunnel safety issues, economic feasibility and regulatory or contractual requirements.

Methodology of risk assessment

The applied methods range from the relatively simple measuring against guidelines and standards to the application of well established empirically and theoretically deducted formulations up to the execution of more complex simulation tools like zone models or field models. Beside a number of tailored inhouse codes and utilities, for the simulation of the aerodynamics and thermodynamics of tunnel fire ventilation, the proven and well established commercial software IDA-RTV (EQUA Simulation AB, Sweden), the public domain code FDS (Fire Dynamics Simulator) and the open source CFD-package OpenFOAM are used.