Ventilation control in complex tunnels – results from system tests

Complex tunnels with multiple slip roads and/or connections to other tunnels pose a big challenge in controlling ventilation in the case of fire. This is true for both road and rail tunnels. The aim of a ventilation system is to provide air and smoke management as described in the tunnel safety documentation. In order to do this a software-based control algorithm steers all the required actions of the actuators (fans), based on response information (air velocity).
However, measuring air velocity in a tunnel under given boundary conditions is not a simple task. In addition, the interaction between fans and air movement is strongly influenced by the compressibility of air. Hence, the interaction between fans and air movement requires, on the one hand, a very good control mechanism, and on the other, correct monitoring of the air velocity (feed-back).
The current paper focuses on both, a specific method for calibration of measurement devices for air velocity in a tunnel and the test and adjustment procedures of tunnel ventilation control systems in order to achieve the required ventilation goal.