Flammability limit - Citizendia

Flammability limits, also called flammable limits, give the proportion of combustible gases in a mixture, between which limits this mixture is flammable. Fuel is any material that is burned or altered in order to obtain energy This page is about the physical properties of gas as a state of matter Flammability is the ease with which a substance will ignite causing Fire or Combustion. Gas mixtures consisting of combustible, oxidizing, and inert gases are only flammable under certain conditions. An oxidizing agent or oxidising agent (also called an oxidant, oxidizer or oxidiser) can be defined as either a Chemical compound In English to be inert is to be in a state of doing little or nothing The lower flammable limit (LFL) describes the leanest mixture that is still flammable, i. Lower flammability limit (LFL usually expressed in volume per cent is the lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor e. the mixture with the smallest fraction of combustible gas, while the upper flammable limit (UFL) gives the richest flammable mixture. Increasing the fraction of inert gases in a mixture raises the LFL and decreases UFL.

Flammability limits of mixtures of several combustible gases can be calculated using Le Chatelier's mixing rule for combustible volume fractions $x i$ :

$LFL_{mix}=\frac{1}{\sum \frac{x_{i}}{LFL_{i}}}$

and similar for $U F L m i x$ . Henry Louis Le Chatelier (8 October 1850 - 17 September 1936 was an influential French/Italian Chemist of the late 19th and early 20th centuries

Temperature and pressure also influences flammability limits. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface Higher temperature results in lower LFL and higher UFL, while greater pressure increases both values. The effect of pressure is very small at pressures below 10 millibar and difficult to predict, since it has hardly been studied. The bar (symbol bar) decibar (symbol dbar) and the millibar (symbol mbar, also mb are units of Pressure.

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Flammability is the ease with which a substance will ignite causing Fire or Combustion.

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