Dear Dipil,
As you raised a good question I have bit experience in HVAC because one of my close friend has working as a HVAC Engg I was learned something while we was in iraq.
They mentioned in Presentation its wrong it’s not a damper its ‘’FIRE DAMPER’’. . .
See the below definition which I got from web hope it will solve your query.
DAMPER:
A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air handling equipment. A damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control.
FIRE DAMPER:
Fire dampers are passive fire protection products used in heating, ventilation, and air conditioning (HVAC) ducts to prevent the spread of fire inside the ductwork through fire-resistance rated walls and floors. Fire/Smoke dampers Are similar to Fire Dampers in fire resistance rating, and also prevent the spread of smoke inside the ducts. 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 utilizing detectors remote from the damper, indicating the sensing of heat or smoke in the building occupied spaces or in the HVAC duct system.
Note: Do you remember Mr.Nadhan
https://www.citehr.com/339848-car-c-...must-read.html. He is a HVAC Engg was participate on our most of threads specially HVAC related issues just now I wrote a mail to him regarding this hopefully he will add his inputs soon.
Keep on sharing. . .