Which foam proportioner test checks the volume of foam concentrate that is drawn through the system?

The correct answer involves the foam concentrate displacement method, which is designed to measure the volume of foam concentrate that is drawn through the foam proportioning system. This testing method is effective because it allows operators to directly evaluate the amount of concentrate being utilized in the foam solution during firefighting operations.

By utilizing the displacement method, you can determine whether the proportioner is drawing the correct amount of concentrate relative to the flow of water being supplied. This measurement is critical for ensuring that the foam is effective in suppressing fires, as the correct foam-to-water ratio is essential for optimal performance.

The other options reference different types of tests that do not specifically measure the volume of concentrate drawn through the system. The foam solution refractivity and conductivity tests primarily assess the quality and concentration of the foam solution rather than the volume of concentrate utilized. Meanwhile, the foam concentrate pump discharge volume method would measure the discharge from the foam concentrate pump rather than the actual amount being incorporated into the foam mixture. Therefore, the foam concentrate displacement method is the most suitable way to verify the volume of foam concentrate being drawn.