Safety of LPG rail transportation: influence of safety barriers

The risk due to the road and rail transportation of liquefied petroleum gas (LPG) is well known. Severe scenarios were caused by road or rail accidents involving LPG pressurized tank cars. Consolidated approaches exist for the analysis, the prevention and the mitigation of risk due to the transportation of hazardous materials (HazMat) by road or rail. In Europe a specific regulation applies to the equipment used for the transport of HazMat and specific regulations apply to the qualification of equipment used for LPG transportation. Nevertheless, on June 29th, 2009, an extremely severe transportation accident involving LPG took place in the station of Viareggio, in Italy. A train carrying 14 tank cars of LPG derailed and several railcars overturned on the shunts in the Viareggio station. A tank was punctured, releasing its entire content that ignited causing an extended and severe flash-fire. The present study focused on the study of the effect of different parameters on the heavy gas cloud dispersion resulting from the accident, such as meteorological parameters and height of safety walls. It was found that, to be effective, the mitigation barriers must be carefully designed, with particular reference to their height with respect to the height of the heavy gas cloud.