Load & DesignQuestion 17 of 110
A branch duct must deliver 200 CFM at a velocity of about 600 feet per minute. Approximately what free area is required?
a.0.10 square feet
b.0.20 square feet
c.0.33 square feet
d.0.66 square feet
Explanation
Area equals CFM divided by velocity: 200 / 600 = 0.33 square feet. This corresponds to roughly a 8-inch round duct. Selecting the right size keeps velocity and noise within acceptable limits.
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