Final answer:
AFFF extinguishers are intended to be used on Class B fires that involve flammable or combustible liquids. The fluorinated solution creates a barrier that smothers the fire and prevents re-ignition, making it effective for fighting large-scale liquid fires.
Step-by-step explanation:
AFFF (Aqueous Film Forming Foam) extinguishers are designed to be used on fires involving flammable liquids. These fire extinguishers use a fluorinated solution that spreads across the surface to smother the fire and prevent the vapors from reigniting. While AFFF can be used for multiple types of fires, it is primarily intended for Class B fires, which involve flammable or combustible liquids such as gasoline, kerosene, grease, and oil.
AFFF extinguishers work by releasing a foam that covers the fire, blocking oxygen and extinguishing the flames. The foam is effective on liquid fires because it can float on the surface and suppress the fire's ability to breathe. It's important to note that AFFF extinguishers should not be used on fire extinguisher systems foaming plastics, as they can degrade certain types of plastics.