Millwright Level 1 Practice Exam 2025 – All-in-One Guide to Master Your Certification!

The class of fire that involves vapors is classified as flammable liquids, which is represented by the Red Square (B). This class includes fires fueled by liquids that evaporate readily and produce vapors that can ignite. Common examples include gasoline, oil, and solvents.

Understanding that vapors play a crucial role in this class of fire is important for recognizing the dangers associated with flammable liquids. These vapors may ignite at ambient temperatures, posing significant risks. Effective fire suppression methods for this class typically include using foam fire extinguishers or dry chemical agents specifically designed to smother the flames and prevent the vapors from reigniting.

The other classes identified do each pertain to specific materials or types of fires. For instance, Class A typically involves ordinary combustibles, Class B involves flammable liquids, and Class D is concerned with combustible metals, while Class C deals with electrical fires. Recognizing these distinctions helps in both fire prevention and while fighting fires, ensuring that the appropriate methods are employed, especially when dealing with flammable vapors.