A fire damper is an important component of a heating, ventilation, and air conditioning (HVAC) system. It is designed to protect a building from the spread of fire by closing off the air ducts when a fire is detected. Fire dampers are typically installed in the walls and ceilings of buildings and are usually made of steel or aluminum. They are usually equipped with a fusible link, which is a heat-sensitive device that triggers the damper to close when the temperature reaches a certain level. Fire dampers are designed to close off the air ducts and prevent the spread of smoke and flames throughout the building. They are an essential part of any fire safety system and should be inspected and maintained regularly to ensure they are functioning properly.