The application rate of Class B foam is given in what units?

• A. Liters Per Minute Per Square Meter
• B. Gallons Per Minute Per Square Foot
• C. Gallons Per Hour Per Square Foot
• D. Barrels Per Minute Per Square Foot

Answer: (B)

The rate at which Class B foam is applied is about how much foam solution you deliver over a given area in a given time. In ARFF practice, this is expressed as gallons per minute per square foot, which directly ties the flow rate to the surface area you’re trying to cover. This unit makes it easy to calculate total foam flow: multiply the rate (gpm/ft^2) by the affected area (ft^2) to get gallons per minute total. Using a per-hour or nonstandard unit would not reflect the rapid, area-focused application needed for hydrocarbon fires, and barrels per minute per square foot isn’t a recognized or practical measure. Some may use liters per minute per square meter in metric contexts, but the typical US convention is gallons per minute per square foot.