A fire-actuated damper shall be installed in the supply air plenum at each point where a supply air duct inlet or supply air outlet penetrates the ______.

A fire-actuated damper shall be installed in the supply air plenum at each point where a supply air duct inlet or supply air outlet penetrates the ______.

• A. Outer Shell
• B. Duct Liner
• C. Continuously Welded Shell of the Assembly
• D. Fire-rated Barrier

Answer: (C)

The main idea is that fire dampers must be placed at penetrations of a fire-resistance–rated barrier so that the barrier’s integrity is preserved. The damper is installed in the continuously welded shell of the barrier assembly that surrounds the duct as it passes through the fire-rated partition. This continuous weld creates a solid, fire-stopping path around the damper housing, preventing flame and heat from bypassing the barrier via gaps or non-welded joints. If the damper were placed in the duct liner, outer shell, or any non-continuous portion, gaps could form around the opening and undermine the barrier’s fire rating. By mounting the damper in the continuously welded shell of the assembly, the fire rating of the penetration is maintained while still allowing the damper to operate to stop the fire from spreading through the duct system.

The main idea is that fire dampers must be placed at penetrations of a fire-resistance–rated barrier so that the barrier’s integrity is preserved. The damper is installed in the continuously welded shell of the barrier assembly that surrounds the duct as it passes through the fire-rated partition. This continuous weld creates a solid, fire-stopping path around the damper housing, preventing flame and heat from bypassing the barrier via gaps or non-welded joints. If the damper were placed in the duct liner, outer shell, or any non-continuous portion, gaps could form around the opening and undermine the barrier’s fire rating. By mounting the damper in the continuously welded shell of the assembly, the fire rating of the penetration is maintained while still allowing the damper to operate to stop the fire from spreading through the duct system.