Foam proportioner is defined as:

• A. A device that injects foam concentrate into the water stream.
• B. Foam expansion by adding air to foam solution.
• C. Device that injects the correct amount of foam concentrate into the water stream to make the foam solution.
• D. An inline eductor placed along the length of a hoseline.

Answer: (C)

Foam proportioner is the device that injects the correct amount of foam concentrate into the water stream to make the foam solution. In firefighting, getting the right concentrate-to-water ratio is essential for creating effective foam that cools, blankets the fuel, and suppresses vapors. The proportioner continuously adds the concentrate at the specified proportion as the water flows, so the resulting foam solution has the intended properties, even with changes in flow.

This distinguishes it from simply injecting concentrate, which may not ensure the proper ratio; from foam expansion by air, which is about creating foam structure rather than mixing in the concentrate; and from an inline eductor as a specific design, since the concept is about proportioning the concentrate into the water, not a particular hardware form.