# What Does Cfm Stand For?

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what does cfm stand for? is there some way we can calculate this.

exampel: my case is ca 35 liters, i have 4 case fans at 28 cfm. how fast will they change the air in my case?

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cubic feet per minute.

here's a link for metric conversions:

Metric Conversion

according to my calculations, 35 liters would only be 1.236 cf. actually figuring out how long it will take to cycle your case air depends on the fan configuration.

Edited by upok

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I got 2 seconds. Does that sound right?

That can't be right.

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wekll mine should cycle in less than 1 second because i have 60cfm going in a 60 cfm going out

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yeah, it wouldn't take long. if there are two intake and two exhaust, then theoretically there should be 56 cfm of airflow. that would be .9333 cf/sec. with a case volume of 1.236 cf, then time for air cycle would be 1.324 sec. that doesn't seem right does it?

maybe it is

Edited by upok

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i don get it.... if its 1236 cf, and my fans move around 100 cfm it would take 12 min??

that cant be right??

is there no math expert here???

Edited by leifeinar

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don't think about it as terms of "pulling out all the old air and putting in new air"

think about it more of a room temp... its hot in the room, you turn the air on.. how long does it take for you to feel the temp change?

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yeah, it wouldn't take long.  if there are two intake and two exhaust, then theoretically there should be 56 cfm of airflow.  that would be .9333 cf/sec.  with a case volume of 1.236 cf, then time for air cycle would be 1.324 sec.  that doesn't seem right does it?

maybe it is

484385[/snapback]

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i don get it.... if its 1236 cf, and my fans move around 100 cfm it would take 12 min??

that cant be right??

is there no math expert here???

484387[/snapback]

it's not 1236 cf, it is 1.236 cubic feet. as in just over one and a quarter cubic feet, not one thousand two hundred thirty six cubic feet.

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it's not 1236 cf, it is 1.236 cubic feet.  as in just over one and a quarter cubic feet, not one thousand two hundred thirty six cubic feet.

484408[/snapback]

thats actually just LESS than 1 and a 1/4 cubic feet.. = 1.25

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sorry guys, not twelve hundred cf but 1,2 was sleepy last night.

so if i devide my 100cf by 60 it gives 1,66 cf pr.sec

this means that it takes less than a second to change the air in the case.

so who need noisy high cfm case fans? 1 sec or 0,5 sec should not mather.

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I don't think it's that cut 'n' dry guys. Their's a lot of blocked air and weird turbulence inside computer cases. If it exchanged all the air in one second or less, ambient case temps would be a lot lower.