What is the primary purpose of a foam eductor?

The primary purpose of a foam eductor is to draw foam concentrate into the water stream. This device is designed to create a mixture of water and foam concentrate to generate a foam solution that can be applied to suppress flammable liquid fires. The eductor functions by using the principle of venturi, where water flows through a nozzle, creating a vacuum that draws foam concentrate into the stream. When the foam is applied, it forms a blanket that helps to smother the fire by separating the fuel from the oxygen, which is crucial for effective fire suppression.

The other options, while related to fire suppression techniques, do not accurately describe the function of the foam eductor. Increasing water pressure is more associated with fire hose management or pump operations, cooling heated surfaces is typically related to water application in fire extinguishment, and mixing water with chemical retardants pertains to different methods of fire control that do not involve foam concentrate.