Which device ensures foam concentrate is mixed into the fire stream at the proper percentage?

• A. Foam Eductor
• B. Foam Nozzle
• C. Foam Mixer
• D. Foam Proportioner

Answer: (D)

The main idea here is that foam must be added to the water at a precise, fixed percentage to create the proper foam solution. That requires a device that meters a specific amount of foam concentrate into the water flow as it passes through, so the mix stays at the intended ratio even as flow or pressure changes. The foam proportioner is designed to do exactly this, delivering a calibrated amount of concentrate into the water line and maintaining the set proportion across the system’s operating range. Because of its built-in metering, the foam solution remains at the proper concentration, which is essential for effective blanket and cooling. A foam eductor relies on venturi suction and can vary with pressure and flow, so the mixture isn’t as reliably constant across conditions. A foam nozzle or foam mixer handles the foam output or blending but doesn’t inherently enforce a fixed, correct proportion.