What size spiral duct for 2000 cfm?

To determine the appropriate size of spiral duct for a flow rate of 2000 CFM (cubic feet per minute), you can use the equation for air velocity and the duct's cross-sectional area. A common rule of thumb is to aim for an air velocity of around 900 to 1,200 feet per minute. For 2000 CFM, a duct diameter of approximately 14 to 16 inches is typically suitable, but it's advisable to consult duct sizing charts or a professional to account for specific system conditions and requirements.