If a duct measures 36 in. x 24 in. and has an average velocity of 600 fpm, what is the CFM?

To determine the CFM (Cubic Feet per Minute) of air moving through a duct, you can use the formula:

CFM = Area (in square feet) × Velocity (in feet per minute).

First, you need to calculate the cross-sectional area of the duct. The dimensions of the duct are 36 inches by 24 inches. To find the area in square feet, convert the dimensions from inches to feet:

• 36 inches ÷ 12 inches per foot = 3 feet

• 24 inches ÷ 12 inches per foot = 2 feet

Now, multiply these two measurements to find the area:

Area = 3 feet × 2 feet = 6 square feet.

Next, use the average velocity provided (600 fpm) to find the CFM:

CFM = 6 square feet × 600 fpm = 3600 CFM.

Thus, the calculated CFM of 3600 is confirmed by applying the calculations correctly to the given dimensions and velocity, making this the correct answer.