In fire suppression, what does the term 'expansion ratio' refer to?

The term 'expansion ratio' in fire suppression specifically refers to the volume of foam produced relative to the liquid concentrate. This is a crucial measure as it determines how much aerial coverage the foam can provide when deployed. The expansion ratio is an important factor since the greater the expansion ratio, the more effective the foam can be in smothering flames, insulating surfaces, and creating a barrier against fuel vapors.

Understanding the expansion ratio helps firefighters evaluate the foam's performance and its efficiency in suppressing various types of fires, particularly those involving flammable liquids. It essentially indicates how much the foam can expand and cover an area when mixed with air, impacting its effectiveness in various fire scenarios.