Definition - What does Combustible Limit mean?
Combustible limit refers to the range between which a flammable material is able to be ignited with the introduction of an ignition source. Ignition may be in the form of deflagration, detonation or explosion. Deflagration occurs when the velocity of propagation of the combustible material happens at less than the speed of sound. Detonation occurs when propagation is greater than the speed of sound. Explosions happen when a container ruptures as a result of the build-up of internal pressure.
Safeopedia explains Combustible Limit
The combustible limit is defined by the lower and upper explosive limits. If there is less than 5% of methane in the atmosphere, no ignition can take place. The lower explosive limit is the lowest amount of a gas or vapor in the air that is able to produce an ignition in the presence of an ignition source. The upper explosive limit is the highest amount that will produce an ignition.