INVESTIGATION ON A CAR PARK FIRE

摘要

This work deals with the reconstruction through modeling of a fire developed during the night in a pilotis flooron the ground level of a multi-storey building where several cars, parked there, were burned and the building suffered agreat level of damage. The most probable cause of the fire was an ignition of car due to arson, and since the ceiling of thepilotis floor was covered with polystyrene, the fire quickly developed through lateral flame spread, so transmitting heatback to the cars parked and causing a fire to settle. Because of this event 38 cars and 8 motorcycles, parked on the pilotisfloor behind the entrances of a residential building 120 meters long and 27 meters high with 8 floors, were totallydestroyed, and the pipelines for gas, water, electricity and wastewater were broken. The jetfire of the pressurised gasreleased from the pipeline running along the ceiling of the pilotis floor contributed to the severity of the fire, even if noexplosion fortunately occurred. The people living in the building were kept outside for safety reasons and the buildingwas placed under attachment by the Attorney General. Fire investigation was then requested in order to ascertain if thefire was due to fault or arson and, in case of arson, if the fire started from one or more cars (this change the charge). Thereconstruction of the fire presented herein is twofold based: test results and fire dynamics submodels. The test resultscome from proper reaction to fire tests made on some polystyrene panels coming from the pilotis floor, not destroyed bythe fire. The fire dynamics submodels come from the description of the event observed: plume fire from one or more cars,ceiling jet, lateral flame spread and high rate of heat feedback. The combination of tests and fire dynamics makes thuspossible a plausible reconstruction of what was observed. The outcome of this integral approach has been the numericalcounterpart of the physical fire observed, where an interesting result of the simulation is the occurrence of the wave offire traveling through the cars and the effect of acceleration of this wave induced by the combustible ceiling of the carpark enclosure. It is worth noting that the same wave traveling fire has been observed during the event really occurred.