Eduction (induction) is a foam proportioning method that uses...

• A. Manual mixing in a container.
• B. Premixing foam concentrate in a container.
• C. The pressure energy in the stream of water to induct foam concentrate into the fire stream.
• D. A venturi device to draw foam.

Answer: (C)

Induction (or eduction) foam proportioning works by using the energy of the flowing water to pull foam concentrate into the stream. As water moves through a constricted path in an eductor or venturi, its velocity rises and pressure drops, creating suction that draws foam concentrate from its container into the water, mixing to form foam the moment it exits toward the fire. This is why the statement describing using the pressure energy in the water stream to induct foam concentrate best captures the mechanism. Manual mixing or premixing foam concentrate bypasses this energy-driven entrainment, and while a venturi device is involved in the actual drawing, the essential idea is the pressure energy of the water doing the inducing rather than just the presence of a venturi.