Mixing water with foam concentrate to form a foam solution is referred to as:

• A. Dilution.
• B. Blending.
• C. Proportioning.
• D. Mixing.

Answer: (C)

Proportioning. In firefighting foam systems, the goal is to combine foam concentrate with water at a specific, controlled ratio to create a foam solution with the required expansion, stability, and burn‑range performance. This controlled mixing is done with a proportioning device (like an eductor or in-line proportioner) that meters the concentrate into the water stream at the correct rate. If you simply dilute or mix without this metering, you can dilute too much or too little, leading to poor foam quality and ineffective suppression. Dilution, blending, and generic mixing describe broader, less precise processes and don’t inherently convey the need for a defined concentrate-to-water ratio.