2.2 Flammable limits
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2.2 Flammable limits

  2.2.1 A mixture of hydrocarbon gas and air cannot ignite unless its composition lies within a range of gas in air concentrations known as the “flammable range”. The lower limit of this range, known as the “lower flammable limit” is any hydrocarbon concentration below which there is insufficient hydrocarbon gas to support combustion. The upper limit of the range, known as the “upper flammable limit” is any hydrocarbon concentration above which there is insufficient air to support combustion.

  2.2.2 The flammable limits vary somewhat for different pure hydrocarbon gases and for the gas mixtures derived from different petroleum liquids. In practice, however, the lower and upper flammable limits of oil cargoes carried in tankers can be taken, for general purposes, to be 1% and 10% hydrocarbon by volume, respectively.


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