Cooperative Personnel Services Firefighter (CPS) Practice Exam 2026 – The All-in-One Guide to Master Your Firefighter Exam Success!

The Lower Flammability Limit (LFL) indicates the leanest mixture of fuel that will not burn. This means that when the concentration of fuel in the air falls below this threshold, the mixture is too weak to support combustion. Understanding LFL is critical in fire safety and prevention, as it helps in assessing the risk of fire or explosion in environments where flammable materials are present.

When the concentration of fuel is at or above the LFL, it has enough vapor present to ignite if there is an ignition source. For effective safety measures, preventing fuel concentrations below the LFL can help avoid potential fire hazards, making it a key factor in risk assessments and fire control strategies. This knowledge helps firefighters and safety personnel respond effectively to incidents and mitigate fire risks in various environments.