Full-scale fire tests in the Morgex north tunnel

Some severe fires in Europe, such as those of the Mont Blanc, Gotthard and Tauern tunnels, have clearly displayed the dramatic urgency of adapting the road and rail tunnels to higher safety standards. From 2004 the European directive 2004/54/EC requires risk analysis for existing tunnels of the trans-European road network that are considered below the minimum safety standards. Those risk analysis procedures have to develop and combine proper models to calculate the flux of danger between the sources and the targets (people, infrastructure and the environment): so, since experimental tests are often not feasible, a key role is nowadays played by computer simulations and fire models. Moreover, the use of computational fluid dynamics (CFD) in this field can be useful for the development of fire protection systems, for designing adequate ventilation systems (for both ordinary and emergency conditions) and defining necessary escape routes. A transient real-scale fire test (with a heat release rate, HRR, of about 15 MW) has been conducted in July 2012 in the Morgex north tunnel (Italy). This fire test allowed to collect different measurements (temperature, air velocity, smoke composition, pollutant species) useful for validating and improving the CFD codes and for testing the real behavior of the tunnel and its safety systems during a diesel oil fire with a significant HRR. In this work, the transient fire dynamics is presented with particular attention to the temperature measurements which are discussed and compared to both theoretical and empirical correlations and literature measurements obtained in other tunnel fire tests. The test saw the fundamental cooperation of Corpo Valdostano Vigili del Fuoco (fire fighters) and RAV SpA (tunnel owner).