What is the preferred attack line for Class B fires, such as auto fires?

The preferred attack line for Class B fires, including auto fires, is foam. Foam is effective in suppressing flammable liquid fires because it creates a barrier that smothers the fire, cutting off the oxygen supply to the burning materials. This is particularly important in Class B fires, which involve hydrocarbons or flammable liquids that require specific methods to extinguish.

Using foam is advantageous because it not only extinguishes the fire but also prevents re-ignition by forming a thermal blanket over the surface of the burning liquid. This is crucial in auto fires where both flammable liquids and various materials can be present.

While water can be used in some situations, it may not be effective for Class B fires and, in some cases, could exacerbate the problem by spreading the burning liquid. Similarly, while dry chemical agents can be effective, they may not provide the same level of smothering or re-ignition prevention as foam. Chemical foam, which incorporates specific additives to enhance the smothering effect, can also be an option but is not as commonly considered as standard foam for initial attack.

Thus, foam remains the preferred and most effective method of attack for Class B fires due to its ability to suppress flames and prevent re-ign