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Old 2017-12-03, 8:17pm
aommaster aommaster is offline
Marblemaker in the making
Join Date: Apr 12, 2017
Location: Dubai
Posts: 10

In addition to what Speedslug said, I'd like to also bring your attention to another aspect of fan sizing.

Exhaust fans are specified with two parameters, the volumetric flow rate of air moved (the CFM) and the maximum developed pressure, or suction head. The head is normally provided in units of water column inches (you'll see things like 0.3 inches water column) or Pascals (around 75 pascals).

You'll have to make sure that the fan is able to develop the necessary pressure in order to overcome pressure drop as a result of ducting and elbows. From your description, it looks like there are no elbows or any other constrictions in your duct that can cause a pressure drop, which means the pressure drop in your duct is very minimal. Note here that a pressure drop still exists, but it's not a significant amount, and any small fan will be able to overcome that drop.

However, if you do decide to modify the design of your ducting, the pressure drop is something you should also consider.
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Last edited by aommaster; 2017-12-03 at 11:03pm.
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