During firefighting operations, what is the primary use of medium-expansion foam?

Medium-expansion foam is primarily utilized for smothering fires. This type of foam has the ability to create a thick blanket over a burning surface, effectively cutting off the oxygen supply to the fire and reducing its intensity. By smothering the flames, medium-expansion foam can help suppress the fire rapidly and minimize the risk of re-ignition.

The chemical composition of medium-expansion foam allows it to form a stable layer that covers both liquid and combustible solids, making it effective in various firefighting scenarios, especially for flammable liquids. The foam's expansion capabilities help it to envelop the burning material, providing a cooling effect while simultaneously isolating the fire from the surrounding environment.

In contrast, while options such as transporting firefighters and cooling structures may play roles in some firefighting tactics, they do not relate directly to the primary function of medium-expansion foam. Additionally, creating barriers is more characteristic of certain types of fire attack strategies or other firefighting agents, rather than the specific use of medium-expansion foam.