Water spray interaction with liquid spill in a road tunnel

Interaction between water spray and liquid spillage fires on a sloping road surface was investigated in a laboratory environment. The spill area, fuel flow rates, and fuel types were varied, as were water density and water nozzle types. The total and convective heat release rates were measured using a large fire calorimeter. The total heat release rates of E85 and gasoline were found to be in the range of 3-6 MW, in a burning spill area of approximately 6 m2. The liquid spill was created by a continuous outflow of fuel onto a smooth, sloping concrete surface. After a given time the spill was ignited and, shortly after this, a water spray with a water density of either 10 or 5 mm/min was activated. The purpose of the research was to investigate the interaction between the water spray and the liquid spillage area/heat release rate. There have been concerns expressed that using a water spray inside a road tunnel to deal with an initial spill resulting from a tank leakage incident may exacerbate the situation, as the fuel may float on top of the water and create a larger burning area. These effects were not observed in the test setup presented in this report.