UL Rated Dampers
UL dampers are also designed to prevent the spread of fire and smoke, but they are more general-purpose dampers that can be used in a variety of applications. Underwriters Laboratories (UL), a well-known group that sets safety standards for industrial and commercial products, tests and certifies UL dampers.
UL dampers, fire/smoke dampers, and fire dampers are all designed to prevent the spread of smoke, fire, and other hazardous gasses in the event of a fire. They are usually installed in HVAC ducts and are made to close automatically when the temperature gets too high. This keeps smoke and fire from spreading to other parts of the building.
Fire dampers and fire/smoke dampers are specifically designed to prevent the spread of fire and smoke in HVAC systems.
Fire dampers close automatically when the temperature in the duct reaches a certain level. On the other hand, fire and smoke dampers are made to close when smoke is found in the ductwork to stop the spread of both fire and smoke.