How does the Class B rating compare to a Class 2-A rating in terms of effectiveness?

The Class B rating indicates that an extinguisher is specifically designed for fires involving flammable liquids, such as gasoline, oil, and solvents, while a Class 2-A rating is intended for ordinary combustible materials like wood and paper. The effectiveness of these classes is measured differently due to the nature of the materials they are designed to extinguish.

A Class B extinguisher is critical for handling flammable liquids, while the Class 2-A rating refers to a specific amount of extinguishing capability against ordinary combustibles. When comparing the two, it's important to understand that Class B extinguishers are more effective in containing and extinguishing fires involving flammable liquids. Because flammable liquid fires can spread rapidly and are often harder to control than fires involving ordinary combustibles, serious classification differences arise.

The extremely high effectiveness rated by the Class B rating compared to Class 2-A reflects the challenges associated with flammable liquid fires. Thus, the statement that Class B is "twenty times as effective" underscores the heightened risk and specialized nature of handling flammable liquid fires, emphasizing that a Class B extinguisher is essential for environments where such materials are present and particularly dangerous.