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  1. #1
    Join Date
    Sep 2002
    I don't know

    Air flow relative to duct size

    How much air can a 8 x 5 1/2" rectangular duct flow?
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  2. #2
    Join Date
    Aug 2007
    Northern VA 38 degrees N by 76 degrees W
    It would depend on the velocity and the friction rate that you chose. if you where using around 600 fpm around 160 cfm

  3. #3
    Join Date
    Jun 2010
    Philadelphia PA


    You have been a long time user. Use my profile and I'll be happy to share some simple thoughts that may help
    You have got to learn from other people's mistakes! Because God knows you don't live long enough to make them all yourself !!!!!!!!

  4. #4
    Join Date
    Dec 2005
    Cincinnati, Oh
    Quote Originally Posted by amd View Post
    How much air can a 8 x 5 1/2" rectangular duct flow?
    It would depend, as said, on friction rate, and velocity.

    for your general run of the mill guess, I'd agree somewhere in the 160 range.

    But, as an example:

    10 round caries (general rule) what, 300-400 cfm?
    I've got a system I'm doing where I'm moving 2k cfm through 10", for a special exhaust, and thats design from the manufacturer.

    as a general rule, but does not cover all situations and varies system by system:
    "Better tell the sandman to stay away, because we're gonna be workin on this one all night."

    "Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

    "Just get it done son."

    Dad adjusted

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