What describes foam that has an expansion ratio of 20:1 to 200:1?

The description of foam with an expansion ratio of 20:1 to 200:1 corresponds to medium expansion foam. This type of foam creates a thicker blanket that is effective in smothering flames while providing superior coverage over surfaces. Medium expansion foam is particularly useful in fighting flammable liquid fires, as it can effectively suppress the vapors that contribute to the fire's growth.

Foam with an expansion ratio of less than 20:1 would typically be classified as low expansion foam, which is used for different applications. High expansion foam, categorized as having an expansion ratio greater than 200:1, is designed for use in confined spaces where it can fill large volumes quickly. Concentrated expansion foam is not a standard classification used in firefighting terminology. Understanding these characteristics is essential for effective foam application during fire suppression.