Which type of fuel is not considered a flammable liquid?

Bio-diesel is not considered a flammable liquid in the same way that the other fuel types listed are. Instead, it is classified as a combustible liquid due to its flash point, which is significantly higher than that of flammable liquids. The flash point of a substance is the temperature at which it can form ignitable mixtures with air; combustible liquids typically have a flash point above 100°F (37.8°C), while flammable liquids have a flash point below that threshold.

In contrast, LPG (liquefied petroleum gas) and NG (natural gas) are both considered flammable gases and can ignite easily at relatively low temperatures. Hydrogen, while a gas at room temperature, is also highly flammable and poses particular hazards due to its wide range of flammability in air. Understanding these classifications is crucial for safety during vehicle rescue operations and when handling different types of fuels.