What device is used to automatically interrupt air flow in an air handling system?

The device used to automatically interrupt air flow in an air handling system is a fire damper. Fire dampers are specifically designed to close automatically in the event of a fire, effectively stopping the spread of smoke and flames through the system's ductwork by sealing off the openings. This function is vital for maintaining the safety of a building and protecting occupants by preventing smoke from traveling from one area to another, particularly from areas where a fire might be present to safe zones or escape routes.

The other devices mentioned serve different purposes. A fire pump is utilized to provide water supply during firefighting operations, which is not related to managing air flow in ventilation systems. An air scrubber is designed to clean the air of contaminants and is typically used for air quality improvement rather than fire safety. An exhaust fan removes air from a designated area to facilitate ventilation but does not automatically function to prevent the spread of fire-related hazards. Hence, the fire damper is the critical component that specifically addresses the need for interrupting air flow in the context of fire safety.