What term describes the ratio of finished foam solution after the concentrate is mixed with water and agitated?

The term that accurately describes the ratio of finished foam solution after the concentrate is mixed with water and then agitated is "expansion." In the context of foam application, expansion refers to the increase in volume of the foam solution once the concentrate has been combined with water and agitated. This process creates a stable foam that can effectively suppress fires by coating surfaces and preventing oxygen access.

The concept of expansion is critical in firefighting because the effectiveness of foam in extinguishing fires largely depends on its ability to expand and cover a larger area, providing a blanket over flammable materials. The greater the expansion ratio, the more coverage the foam can offer per unit of concentrate used.

The other terms mentioned do not accurately describe this phenomenon. Concentration typically refers to the amount of foam concentrate present in a solution but does not measure the volume increase resulting from mixing and action. Density relates the mass of a substance to its volume, which is not a measure of foam expansion. Compression would imply a reduction in volume, whereas the process in question involves an increase in volume through agitation. Understanding these definitions helps distinguish the characteristics of different aspects of foam usage in firefighting.