Results, Scenario 2: Door Open + Box Fan Exhaust + Open Window + Circulating Box Fan

Conditions:

Dry ice was used to raise CO₂ levels in the QLFC conference room. When CO₂ reached greater than 2,000 ppm, the CO₂ source was removed from the room and a box fan was placed in a door open to outside air and a 3 x 3 ft window was opened. The time for the CO₂ to reach approximately 37% of the peak level was measured.

Outside CO₂ level = 415 ppm. Peak CO₂ = 2,267 ppm. With the open door, window and exhaust fan, the time for the CO₂ level to drop to <37% peak (931 ppm) was 3 minutes 51 seconds = 0.064 hours.

Result:

With the open door, window and exhaust fan, CO₂ levels dropped rapidly from a peak level of 2,267 ppm to 931 ppm in just 3 minutes 51 seconds. The calculated result indicated that 20 ACH was achieved under these conditions, far exceeding the target of 4 to 5 ACH.