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King's Cross Underground Fire In 1987

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Introduction Within this report I am going to state how the King’s Cross Underground fire in 1987 happened and the evacuation process that the authorities followed. I am also going to state why this incident led to the identification of a method of fire propagation known as the “trench effect”. 1. A brief report on the incident and the evacuation (500) At King's Cross provides both the mainline railway station above ground and subsurface platforms for the Metropolitan line. There are also the underground tube lines for the Northern, Piccadilly, and Victoria lines. There were two separate escalator shafts leading down to the Victoria and Piccadilly lines; the Northern line was reached from the Piccadilly line. Stairs connected the Piccadilly …show more content…

Firstly, David Halliday investigated the scene and decided that the point of origin was on third of the way up the escalator. He was able to determine this as the steps below this point were less charred and the fire spread upwards. He then decided to examine the area underneath the escalator where he only found that the only combustible materials underneath the escalator were a thick layer of grease that had formed naturally from the constant use of the escalators over a long period of time. “The grease had impregnated dust and dirt in it making it easier to become …show more content…

3. Details of the mechanism known as the “trench effect” (500) The two methods that are combined to form the trench effect is based on two well-understood but separate ideas: the Coandă effect from fluid dynamics and the flashover concept from fire dynamics. “The Coandă effect is the phenomena in which a jet flow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial jet direction.” The flash over concept is in a compartment fire there may come a stage where the total thermal radiation from the fire plume, hot gases, and hot compartment boundaries (ceilings and walls) causes the radiative ignition of all exposed combustible surfaces within the compartment. Where the compartment is adequately ventilated in the case of the king’s cross fire it would be the wind from the tubes pushing the air up the escalator, this sudden and sustained transition of a growing fire to a fully developed fire is known as a flashover. Why them together creates the trench effect? These two forces combined created what is called the trench effect due to the way in which the flames go sideways instead of straight up like a general

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