Ducts which serve a Type I hood in buildings more than one story in height, shall be enclosed in a continuous enclosure with a fire resistance rating of not less than _______, from the first fire rated barrier to the exterior of the building.

Ducts which serve a Type I hood in buildings more than one story in height, shall be enclosed in a continuous enclosure with a fire resistance rating of not less than _______, from the first fire rated barrier to the exterior of the building.

• A. 2 hour
• B. 1 hour
• C. 4 hour
• D. 3 hour

Answer: (B)

Ducts that carry exhaust from a Type I kitchen hood are treated as potential fire paths and must be enclosed in a continuous fire-resistance-rated assembly that runs from the first fire-rated barrier to the exterior of the building. In buildings taller than one story, the required rating is not less than one hour. This rating slows or halts the spread of a grease fire along the duct, helping to contain the fire and provide time for occupants to evacuate and for firefighters to respond. Higher ratings are not typically required for standard Type I hood duct runs in multi-story buildings, so the not-less-than one-hour enclosure is the correct requirement.

Ducts that carry exhaust from a Type I kitchen hood are treated as potential fire paths and must be enclosed in a continuous fire-resistance-rated assembly that runs from the first fire-rated barrier to the exterior of the building. In buildings taller than one story, the required rating is not less than one hour. This rating slows or halts the spread of a grease fire along the duct, helping to contain the fire and provide time for occupants to evacuate and for firefighters to respond. Higher ratings are not typically required for standard Type I hood duct runs in multi-story buildings, so the not-less-than one-hour enclosure is the correct requirement.