passive intake, math of many small holes?

[Anti]

So... I know this is pretty much a dead thread... but it has lots of nifty calculations in it, so I imagine people are still reading it (like me).

My question is this:

How would adding a carbon filter to the vent chain affect these formulas?

I have read over and over and over that adding a carbon filter will increase the workload on your fans.. but does anyone have any data (experimental or otherwise) to suggest how much it affects it? Wanna get this right the first time, if at all possible.

thanks!

 

[G0d5hand]

Usually people recommend passive intakes at least twice as large as your exhaust. By twice, I mean twice the cross sectional Area. For example, your 5" exhaust has an area of 19.6 sq inches or (Pi) times (radius squared). An intake hole 2" in diameter has an area of 3.14 square inches (again area=pi times r times r). So you would need 12.5 little 2" passive intake holes.

Drilling 12 holes and then making and painting PVC elbows for those holes would take me all afternoon! Better to buy darkroom louvers and drill one or two big square holes IMO. The black louvers below are 8" X 8".

where you get them from?

 

[icough2getoff]

where you get them from?

http://www.google.com/products?q=darkroom+louver&um=1&ie=UTF-8&sa=N&hl=en&tab=wf