All this 'positive pressure' is doing my head it. The pressure difference between inside of and outside of case is so minimal it is ridiculous. It is less than the difference between the barometric pressure at sea level and 10 feet above sea level .. which is 0.274 mmH2O
As a comparison, positive air pressure cleanrooms (like used for electronics classrooms, optical, aerospace, etc), normally operate at an air pressure range of 0.02 in. (0.51mm) to 0.2 in (5.08mm) H20 above ambient .. about 1/10th as much.
Datavacs work quite well, but using basic vent filters and vacuuming them about once a month when I vacuum house (no, i don't vacuum house once a month, I do it every week) and maybe I'll blow out computer once a year .. at most.
The Emu lives in extreme conditions. But with a face like that it's understandable.
Desert / arid conditions are terrible for dust. I'm in warm moist country. 15-25c with 70-90% humidity. Here we worry more about rust, than dust. Edited by doyll - 8/18/16 at 9:25pm