Quick airflow question

[MichiganDude]

Anyone have any rough idea what percentage of CFM a carbon scrubber will take away? For instance, if I have a 100 CFM fan, will a carbon scrubber degrade that by 40% so I'll only have 60 cfm actual.

Obviously, I want to make sure I have negative pressure, and I'm trying to make sure my inflow is less than my actual outflow with a carbon scrubber attached.

Thanks in advance for any help you can give me.

 

[4EVR420]

MD, love the avatar man! I too would like to know if there is an accurate way to meassure the degridation of cfms by adding a scrubber.

 

[nouvellechef]

I would guess less. Hmm, maybe 10-15 percent.

 

[MichiganDude]

I'll keep looking to see if I can find something out on the internets about it. A crude test like measuring how long it would take to fill a known volume, like a trash bag, before and after might work. I guess then it would be some simple math to figure out the degradation of airflow. Certainly not entirely accurate, but I guess close enough for gubment work.

 

[zem]

if you make the carbon screen surface area big enough you wont lose any cfm, i dunno how to tell how big you need it exactly tho. the bigger surface area also means that the air moves slower through the screen and gets scrubbed better

 

[dman1234]

there is a chart that tells you how big the surface area of your scrubber needs to be in accordanc with your fan size.

anyone know where it is?

but i also believe Zem has it rite if its big it wont slow the fan down.

 

[nouvellechef]

So always one size up. 6" fan=8"scrubber (reducer needed). Two might be over kill.

 

[zem]

the diy carbon filter is long cylindrical shape surface area more than double fan size. the carbon grain size also matters in blocking airflow, finer grains block more air need larger surface area