Air filter material for server room
Our server room has an Expelair fan on an outside wall and a (fire standards appropriate) vent in the door into the sub-basement of the building. The fan pulls air through the room to the outside, when the room becomes warm. We've found that we can get far too much "human detritus" (hair and skin!) coming in from the school, and we can get too much outside dust coming in when the fan is idling. So I think I want some suitable filter material to go in front of both the fan and the door vent.
I've ordered something from Ace Filtration, but they have been absolutely useless delivering it to me. Maybe this is because the order is low £value, but I've lost faith in them now.
If anyone can suggest a suitable supplier/material that would be great!