Using the formula for CFM, if a duct measures 40 inches by 22 inches and the air velocity is 1,500 fpm, what is the CFM?

To determine the CFM (Cubic Feet per Minute) in this scenario, you can use the formula:

[ \text{CFM} = \text{Area (sq ft)} \times \text{Velocity (fpm)} ]

First, you need to calculate the area of the duct in square feet. The duct dimensions are given in inches, so you should first convert these dimensions to feet:

• Width: 40 inches = ( \frac{40}{12} = \frac{10}{3} ) feet

• Height: 22 inches = ( \frac{22}{12} = \frac{11}{6} ) feet

Now, you can calculate the area:

[

\text{Area} = \text{Width} \times \text{Height} = \left( \frac{10}{3} \right) \times \left( \frac{11}{6} \right) = \frac{110}{18} \text{ sq ft} = \frac{55}{9} \text{ sq ft} \approx 6.11 \text{ sq ft}

]

With the area calculated, you can now use the velocity provided, which