What is the significance of the upper flammable limit?

The significance of the upper flammable limit (UFL) lies in its definition, which describes the maximum concentration of flammable vapors in the air that is capable of sustaining combustion. When the concentration of flammable vapors exceeds this limit, the mixture becomes too rich to ignite, meaning that there is insufficient oxygen to support combustion. This concept is crucial for safety in environments where flammable gases or vapors are present, as understanding the UFL helps in preventing explosive conditions that could arise from improper handling or storage of flammable materials. Proper awareness of the UFL enables crews to manage risks associated with fire and explosion on board vessels or in other hazardous environments.