Core TradesQuestion 147 of 700
A room measures 12 ft by 15 ft with an 8-ft ceiling. To provide 6 air changes per hour, what mechanical ventilation airflow is required?
a.120 CFM
b.144 CFM
c.180 CFM
d.96 CFM
Explanation
Room volume = 12 x 15 x 8 = 1,440 cubic feet. Six air changes per hour = 1,440 x 6 = 8,640 cubic feet per hour. Divide by 60 to get CFM: 8,640 / 60 = 144 CFM. The other answers result from using the wrong number of air changes or forgetting to divide by 60.
Law Reference: 2025 CA Mechanical Code, Chapter 4 (Ventilation)Practice all 700 questions free — no signup required.
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