🔍 Key Concepts

• Aqueous Film Forming Foam (AFFF) – what each word in the name tells you about how it works • Difference between chemical foam, mechanical foam, and high‑expansion foam • Common type of foam used on flammable liquid (Class B) fires on ships and aircraft decks

💭 Think About

• Think about what happens when this foam is applied to a fuel fire: does it form a physical blanket, a vapor‑suppressing film, expand a lot in volume, or rely on a chemical reaction in the flame? • Which of the listed options is the general category that includes foams produced by mixing a concentrate with water and air through equipment like proportioners and nozzles? • Is AFFF normally described by its expansion ratio (low/medium/high) or by the way it’s generated (chemical vs mechanical)?

✅ Before You Answer

• Identify which option best matches foam that forms a thin water-based film over hydrocarbon fuels to prevent vapor release • Recall that AFFF is commonly used from fixed shipboard systems and portable foam equipment for oil/fuel fires • Verify which term is used in training manuals to classify foam made by agitation/mixing (induction) rather than by chemical reaction in the fire