A mechanical room is 40 ft by 30 ft by 12 ft high. If temporary exhaust is set for 6 air changes per hour, what exhaust rate is required?
Correct Answer
D) 1,440 cfm
Volume = 40 × 30 × 12 = 14,400 cubic feet. Six changes per hour require 86,400 cubic feet per hour, or 1,440 cfm. The other rates correspond to 5, 7.5 and 10 ACH. The supplied 6 ACH is an exercise target, not proof that an actual hazardous atmosphere is safe.
Why This Is the Correct Answer
Volume = 40 × 30 × 12 = 14,400 cubic feet. Six changes per hour require 86,400 cubic feet per hour, or 1,440 cfm. The other rates correspond to 5, 7.5 and 10 ACH. The supplied 6 ACH is an exercise target, not proof that an actual hazardous atmosphere is safe.
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