What happens below the lower flammable limit?

When a fuel-air mixture is below the lower flammable limit, it is considered too lean to burn. This means that there is insufficient fuel in the mixture for combustion to occur effectively. In practical terms, the concentration of the flammable substance (fuel) is below the minimum level required for a sustained flame, resulting in an inability for ignition to take place.

Understanding the concept of flammable limits is crucial in fire safety and prevention because maintaining the right fuel-air ratio is essential for controlling combustion. If the mixture is lean, even an ignition source will not be able to initiate combustion, which is why it's important for firefighters and safety personnel to be aware of these parameters when assessing fire risks.