A Class B extinguisher with a rating of 40-B would be expected to extinguish which size flammable liquid surface fire when used by a non-expert?

A Class B extinguisher rated at 40-B indicates its effectiveness in handling flammable liquid fires. The number 40 signifies the unit's capability to extinguish a fire covering an area of 40 square feet. Class B extinguishers are specifically designed for flammable liquids such as gasoline, oil, and grease, and the rating of 40-B allows a non-expert user to tackle a flammable liquid fire that occupies this surface area.

Understanding fire fighting equipment ratings is crucial for ensuring that the right extinguisher is used for the appropriate fire type and size. This knowledge helps in selecting an extinguisher capable of handling the expected fire scenario, promoting safety and effectiveness in fire suppression efforts. For the other choices, they either misrepresent the appropriate measurement for this specific extinguisher rating or correspond to areas that exceed its intended operational scope, highlighting the importance of accurate terminology in fire safety.