In the foam testing method using water substitution, how is the percentage of foam produced calculated?

The percentage of foam produced in the foam testing method using water substitution is calculated by taking the volume of water drawn and dividing it by the volume pumped. This method provides a clear way to assess the performance of the foam in creating a reliable and significant volume of foam based on the input of water and the operational capacity of the pumping system. This ratio helps determine how effectively the foam concentrate has mixed with the water to produce foam and is crucial for evaluating the efficiency of fire suppression efforts.

In this context, assessing the volume of water drawn in relation to the volume pumped gives a good indication of how much foam was generated for firefighting purposes. The other options do not provide the necessary information for calculating foam percentage in this testing method: the volume of foam concentrate used, for instance, is not directly usable for this assessment since it doesn't take into account the water that was actually displaced by the foam. Similarly, the volume of air injected or just the water drawn does not give a comprehensive view of the foam generation efficiency when considered independently.