Recently I've been looking at a range of network server cabinets with a mesh door at the rear. At the top of the cabinet are ceiling mounted fans with dust filters attached. These fans suck air out of the cabinet - presumably to remove the hot air that has risen to the top.

My question is why do these fans have dust filters? What point do they serve? If the air flow is pulled in by these fans through the mesh door, then surely they are not there to protect the hardware inside from dust?

Also, there are other minor grilled gaps around the enclosure, how does this kind of ventilation design work?


  • 3
    Not all cabinets are well-designed. Maybe these fans can also be used at the bottom or the front of the cabinet, where the filter makes sense. You should ask the vendor. – Oliver Jun 22 '12 at 7:42
  • First thing I thought when I read about dust filters on the top is that maybe someone along the way read the blueprint upside-down. :D – HopelessN00b Jun 22 '12 at 12:18
  • Have a picture of it or model number? Some cabinets just put filters absolutely everywhere, just to be safe. Or it could be the fans can be flipped around to suck air in if you had an air conditioning vent above the rack. – Grant Jun 22 '12 at 14:10
  • I'm sure the fans can be flipped, but would that help the situation? The square area of the mesh door is much larger than the fan holes. Bringing air in from the top may generate a positive pressure inside the cabinet keeping the dust out, but wouldn't the air head straight out of only the top section of mesh door? (Link added in question) – Nicholas Jun 23 '12 at 8:23

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