What is the minimum allowable air velocity through any duct in feet per minute?

What is the minimum allowable air velocity through any duct in feet per minute?

• A. 400
• B. 450
• C. 600
• D. 500

Answer: (D)

Maintaining a minimum air velocity in kitchen vent ducts keeps grease-laden air moving fast enough to avoid grease settling inside the duct and to ensure it is carried out to the exhaust. The minimum allowable velocity is 500 feet per minute, which protects against buildup that can cause blockages or fires and helps ensure the system performs reliably. If the velocity drops below this value, grease can deposit on the duct walls and reduce efficiency. Velocities at or above 500 fpm are therefore required to consistently transport grease-laden air through the system. The other options are either below the required minimum or simply not the mandated minimum—600 fpm would meet or exceed the requirement but isn’t the minimum, while 500 fpm is the baseline that must be achieved.

Maintaining a minimum air velocity in kitchen vent ducts keeps grease-laden air moving fast enough to avoid grease settling inside the duct and to ensure it is carried out to the exhaust. The minimum allowable velocity is 500 feet per minute, which protects against buildup that can cause blockages or fires and helps ensure the system performs reliably. If the velocity drops below this value, grease can deposit on the duct walls and reduce efficiency. Velocities at or above 500 fpm are therefore required to consistently transport grease-laden air through the system. The other options are either below the required minimum or simply not the mandated minimum—600 fpm would meet or exceed the requirement but isn’t the minimum, while 500 fpm is the baseline that must be achieved.