A duct fire damper is a device used in air conditioning and ventilation systems to prevent the spread of fire. It is designed to close automatically when a fire is detected, thus preventing the spread of smoke and heat through the ductwork. Duct fire dampers are typically installed in the walls and ceilings of buildings, as well as in air conditioning and ventilation systems. They are usually made of steel or other fire-resistant materials, and are typically installed in the ductwork between two rooms or floors. The purpose of a duct fire damper is to limit the spread of fire and smoke by blocking the airflow through the ductwork. In addition, they can also be used to reduce the amount of heat that is released into the building in the event of a fire. Duct fire dampers are an important part of any fire safety system, and should be inspected and maintained regularly to ensure they are functioning properly.