Hoods with fire dampers shall be provided within how many inches from the damper?

Hoods with fire dampers shall be provided within how many inches from the damper?

• A. 6 inches
• B. 12 inches
• C. 24 inches
• D. 18 inches from the damper

Answer: (D)

Fire dampers are installed in exhaust ducts to stop fire from traveling through the ductwork. Placing the damper within a short distance from the hood ensures the protected, rated portion of the duct is as close as possible to the source of heat and flames, so the damper can close quickly and effectively. The standard requires the fire damper to be within 18 inches of the hood, keeping the run between hood and damper short enough to minimize an unprotected duct path and to maintain proper response and performance of the automatic shutoff. Distances like 6 or 12 inches would not align with the intended protection and practical installation, while 24 inches would leave too long a gap between the hood and the damper, reducing the effectiveness of the fire-stop arrangement.

Fire dampers are installed in exhaust ducts to stop fire from traveling through the ductwork. Placing the damper within a short distance from the hood ensures the protected, rated portion of the duct is as close as possible to the source of heat and flames, so the damper can close quickly and effectively. The standard requires the fire damper to be within 18 inches of the hood, keeping the run between hood and damper short enough to minimize an unprotected duct path and to maintain proper response and performance of the automatic shutoff. Distances like 6 or 12 inches would not align with the intended protection and practical installation, while 24 inches would leave too long a gap between the hood and the damper, reducing the effectiveness of the fire-stop arrangement.