Which classes of fire extinguisher include a number in their classification?

Fire extinguishers are classified according to the type of fire they are designed to combat. Classes A and B are specifically designed for different categories of combustibles, and they include a numerical designation that indicates the size of the extinguisher's effectiveness.

Class A extinguishers are used for ordinary combustible materials like wood, cloth, paper, rubber, and many plastics. The numerical rating for Class A indicates the amount of water in gallons that an extinguisher would effectively put out, with the rating indicating the relative effectiveness in extinguishing fires of this class.

Class B extinguishers are intended for flammable liquids such as gasoline, oil, grease, and paints. Like Class A, Class B extinguishers are deemed effective based on numerical ratings that correspond to the size of the fire they can extinguish, usually in terms of square feet.

In contrast, Class C extinguishers are for electrical fires and do not include a number in their classification since they are typically rated by the voltage of the electrical equipment they can safely extinguish without conducting electricity. Other classes, such as Class D for combustible metals and Class K for cooking oils and fats, also have different classification systems.

Therefore, the correct answer relates to the fact that Classes A and