### Some info about cfm calculations

Posted:

**Fri Jan 27, 2012 11:18 pm**Hi,

For my machine, I'm looking to make an exhaust to be 100% sure all air from inside the laser chamber is extracted through a hose (2m long) and out of my window

I calculated that that the total area of my machine (the part where parts are lasered) is 1200x800x400 mm big, so thats aproximately 384 liters of air

I found a 252 cfm pc fan (DELTA make)

252 cfm seems to convert to 119 liters per second.

Does that mean that theoretically this fan can move the comlete air content of my machine in about 3.2 seconds ?

Am I also right that this is theoretically because it assumes that there is no static pressure inside the machine, so the fan has no back pressure which makes it harder to suck up enough air ?

On the specs of the fan there is mentioned a maximum air pressure of 35.877 of H2O. What can I calculate with that ?

Can I somehow know how many holes are needed in the case so that enough fresh air can come in to be sucked away then by the fan ?

Any help would be very appreciated. I am not that familiar with these calculations.

Kind regards,

Bart

For my machine, I'm looking to make an exhaust to be 100% sure all air from inside the laser chamber is extracted through a hose (2m long) and out of my window

I calculated that that the total area of my machine (the part where parts are lasered) is 1200x800x400 mm big, so thats aproximately 384 liters of air

I found a 252 cfm pc fan (DELTA make)

252 cfm seems to convert to 119 liters per second.

Does that mean that theoretically this fan can move the comlete air content of my machine in about 3.2 seconds ?

Am I also right that this is theoretically because it assumes that there is no static pressure inside the machine, so the fan has no back pressure which makes it harder to suck up enough air ?

On the specs of the fan there is mentioned a maximum air pressure of 35.877 of H2O. What can I calculate with that ?

Can I somehow know how many holes are needed in the case so that enough fresh air can come in to be sucked away then by the fan ?

Any help would be very appreciated. I am not that familiar with these calculations.

Kind regards,

Bart