Devices designed to impede the spread of fire through walls, floors and partitions. Fire dampers are installed in the ducts of heating, ventilation and air conditioning systems which penetrate fire-resistant constructions. When a rise in temperature occurs, the fire damper closes, usually activated by a thermal element which melts at temperatures higher than ambient but low enough to indicate the presence of a fire, allowing springs to close the damper blades. Fire dampers can also close following receipt of an electrical signal from a fire alarm system utilising detector remote from the damper, indicating the sensing of heat or smoke in the building occupied spaces or in the HVAC duct system.
