For a duct measuring 40 inches by 22 inches with an air velocity of 1,500 feet per minute, the calculated CFM is approximately 9,167.

For a duct measuring 40 inches by 22 inches with an air velocity of 1,500 feet per minute, the calculated CFM is approximately 9,167.

• A. False
• B. Not enough information
• C. Approximately 9,000 CFM
• D. True

Answer: (D)

The test is about calculating CFM from a duct’s cross-sectional area and air velocity. CFM equals cross-sectional area (in square feet) times velocity (in feet per minute). Convert the duct size to square feet: 40 inches by 22 inches gives 40 × 22 = 880 square inches. Since there are 144 square inches in a square foot, the area is 880 / 144 ≈ 6.11 ft². Multiply by the velocity: 6.11 ft² × 1,500 ft/min ≈ 9,166.5 CFM, which rounds to about 9,167 CFM. So the statement is true.

The test is about calculating CFM from a duct’s cross-sectional area and air velocity. CFM equals cross-sectional area (in square feet) times velocity (in feet per minute). Convert the duct size to square feet: 40 inches by 22 inches gives 40 × 22 = 880 square inches. Since there are 144 square inches in a square foot, the area is 880 / 144 ≈ 6.11 ft². Multiply by the velocity: 6.11 ft² × 1,500 ft/min ≈ 9,166.5 CFM, which rounds to about 9,167 CFM. So the statement is true.