Which device placed in HVAC ductwork that penetrates rated walls or floors helps restrict the spread of heat and/or smoke?

Which device placed in HVAC ductwork that penetrates rated walls or floors helps restrict the spread of heat and/or smoke?

• A. Fire/Smoke Dampers
• B. Duct Heaters
• C. Smoke Detectors
• D. Vent Fans

Answer: (A)

Fire/Smoke dampers are placed in ductwork where it pierces fire-rated walls or floors to stop the passage of heat and smoke between compartments. When heat is detected or a fire control system is activated, these dampers automatically close, sealing the duct and preserving the integrity of the rated barrier. That direct action—physically blocking the path through the duct—is why this option is correct. Duct heaters add heat to the air and don’t prevent spread. Smoke detectors sense smoke but don’t block passage. Vent fans move air and can spread smoke; they don’t seal barriers.

Fire/Smoke dampers are placed in ductwork where it pierces fire-rated walls or floors to stop the passage of heat and smoke between compartments. When heat is detected or a fire control system is activated, these dampers automatically close, sealing the duct and preserving the integrity of the rated barrier. That direct action—physically blocking the path through the duct—is why this option is correct. Duct heaters add heat to the air and don’t prevent spread. Smoke detectors sense smoke but don’t block passage. Vent fans move air and can spread smoke; they don’t seal barriers.