P : represents the power to be dissipated (in watts)
Δt : represents the temperature difference between internal temperature of the equipment and ambient temperature
Q : represents the air flow of the fan = P(w)1.2XΔt L/s
THE AIR FLOW IS DETERMINED BY THE PROJECTION ON THE GRAPH BELOW FROM THE INTERSECTION POINT OF THE LINES AND Δt ON THE AIR FLOW SCALE.
Example given a power to dissipate of 400 W and t of 10℃
REQUIRED AIR FLOW TO COOL = 34 L/s = 72 CFM
(CFM = L/s x 0.0353 x 60)