Final answer:
A 10 "B" rated extinguisher has the potential to extinguish up to 10 square feet of a Class B fire, which involves flammable liquids. The number indicates the extinguisher's relative power in ideal test conditions, though effectiveness can vary in real situations.
Step-by-step explanation:
A 10 "B" rated extinguisher indicates that it has the potential to extinguish up to 10 square feet of a Class B fire. Class B fires are fires that involve flammable liquids such as gasoline, oil, and grease. The rating system for fire extinguishers is a combination of letters and numbers, where the letter indicates the type of fire the extinguisher is designed to combat and the number provides a relative measure of the extinguishing capability for that type of fire.
The number in a Class B extinguisher rating denotes the approximate square footage of a flammable liquid fire that a non-professional user should be able to extinguish under ideal test conditions. Therefore, a '10 B' rating means the extinguisher can cover 10 square feet of a Class B fire.
It is important to note that in actual fire situations, the effectiveness can vary based on many factors, such as the nature and spread of the fire, the experience of the user, and the specific extinguishing agent in the unit.