When foam concentrate is introduced into a fire line, what is the correct method?

• A. Injected at the nozzle
• B. Added at the pump
• C. Inducted into the line
• D. Mixed with water in hydrant

Answer: (C)

Inducting the foam concentrate into the water line using a foam inductor (or other proportioning device) is the correct method. This approach pulls concentrate from its reservoir into the flowing water at a controlled ratio, producing a consistent foam solution as it travels to the nozzle. It ensures proper mixing regardless of pump pressure or flow changes, and keeps the concentrate separate from the hydrant water until it’s properly proportioned.

Injecting at the nozzle can lead to uneven mix and potential nozzle issues, since there’s no guaranteed metering once the water and foam converge at the nozzle. Adding at the pump or mixing in the hydrant are not reliable methods for maintaining the correct, uniform proportion throughout the stream.