If the application rate of Class A foam for a 2000 square foot fire is 0.25 gpm/square foot and the nozzle gpm is 200 gpm, how much will the nozzle fall short of the application rate?

• A. 0.05 gpm/square foot
• B. 0.10 gpm/square foot
• C. 0.15 gpm/square foot
• D. 0.20 gpm/square foot

Answer: (C)

To determine how much the nozzle falls short of the application rate, we first need to calculate the total application rate required for the 2000 square foot area. The application rate is 0.25 gpm per square foot. Thus, the total required flow rate can be calculated by multiplying the application rate by the area:

Total flow rate required = Application rate × Area

Total flow rate required = 0.25 gpm/square foot × 2000 square feet = 500 gpm

Now, the nozzle is producing a flow of 200 gpm. To find out how much this falls short of the required application rate, we subtract the nozzle flow rate from the total flow rate required:

Shortfall = Total flow rate required - Nozzle flow rate

Shortfall = 500 gpm - 200 gpm = 300 gpm

Now, to gauge this shortfall on a per square foot basis, we convert the total shortfall back to a per square foot measurement:

Shortfall per square foot = Shortfall / Area

Shortfall per square foot = 300 gpm / 2000 square feet = 0.15 gpm/square foot

This means the nozzle falls short of the application rate by