Risk analysis of LPG (liquefied petroleum gas) vehicles in enclosed car parks

A risk analysis is presented for an enclosed 30 x 30 m car park in which LPG (liquefied petroleum gas) vehicles are allowed to park. An event tree analysis is used to define 26 different incident scenarios and their probabilities. FLACS, a specialised CFD program, is used to calculate the formation of a flammable vapour cloud and its dilution by means of the ventilation system as well as the overpressures generated in a vapour cloud explosion. Existing empirical methods are used to calculate the overpressures generated by a BLEVE and the heat radiated by a fire ball and a jet fire. The simulations have shown that a release from a 70 I LPG fuel tank can lead to vapour clouds of up to 200 m(3) that fill the entire height of the car park, while the explosion simulations have shown that such vapour clouds can lead to overpressures above 30 kPa in the entire car park. The ventilation simulations have shown that high flow rates of approximately 0.060 m(3)/s per m(2) of car park floor area are necessary to rapidly dilute these large vapour clouds. (C) 2012 Elsevier Ltd. All rights reserved.