Browsing by Author "Gous, Michelle Danille"

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    Experimental and numerical investigation on the fire behaviour of South African passenger trains with an emphasis on arson
    (2022-03) Gous, Michelle Danille; Walls, Richard Shaun; Cicione, Antonio; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Internationally, passenger train fires have become a rare occurrence as trains are tested to strict standards in order to ensure passenger safety. At the same time, arson attacks have become a frequent occurrence on Metrorail trains in South Africa in recent years, resulting in severe damage, huge financial losses, and in some cases, even the injury and death of passengers. Intra-urban passenger trains form a crucial part of the economy as many people rely on this form of public transport to travel to work. Metrorail trains offer a low-cost alternative to other forms of public transport. Arson attacks threaten the existence of passenger trains as a form of public transport as these lead to damage to infrastructure, trains being destroyed and affect business continuity. Little is known about the fire behaviour in the carriages which is causing these very dangerous fires. This study aims to investigate this fire behaviour by using small-scale material tests, large-scale experiments, and full-scale numerical simulations to gain insight into this problem. The small-scale material tests include the determination of material density, bomb calorimeter tests to determine the heat of combustion, and radiant panel tests in order to determine the ignition temperature and critical heat flux, as well as to observe how these materials react to heat. Further material properties are obtained from literature once all material types are identified. The large-scale experiments involve the burning of full seat assemblies on a scale in an open-air environment, while taking heat flux and temperature readings. This is used to determine the mass loss rate of the seats, and are replicated in Fire Dynamics Simulator (FDS) version 6.7.6 numerical simulations to observe the accuracy of the simulation using the parameters determined through smallscale testing, large-scale experiments and literature values where required. To study the approximate fire behaviour in a full-scale passenger train carriage, the carriages are replicated, and the seat models are used in numerical simulations involving various fire scenarios. These include a variation on the ventilation conditions, minimum and maximum, as well as varying the ignition position between the front and middle of the carriage to study the effect these variables have on fire behaviour. The results are used to analyse the tenability conditions and determine the time passengers have to evacuate before experiencing injury or death. Passengers were found to have minimal time to evacuate the carriages, with a high risk of mortalities in the case of a full carriage. Some materials were found to be an extreme fire hazard which contributed to the high heat release rate and all fire scenarios leading to flashover before 300 seconds. The fires were found to be ventilation controlled, even in the maximum ventilation scenarios. All seats were found to be non-compliant when compared to EN 45545-2 requirements, by exceeding the limit of 350 kW on the peak heat release rate, and also exceeding limitations placed on fire spread and flame length.