Ventilation ducting static pressure calculation
Results 1 to 5 of 5

Hybrid View

  1. #1
    Join Date
    Sep 2011
    Posts
    2

    Ventilation ducting static pressure calculation

    Hello,

    I was hoping for a formula to help me calculate static pressure in custom-made (smooth metal) ventilation ducting, given the following information:

    1. Length of duct in meters
    2. Area of cross-section in meters squared
    3. Air flow in meters cubed per hour

    Any pointers would be greatly appreciated!

    amrs

  2. #2
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Why? Is this a theoretical question or related to a real world design?
    Is the duct perfectly straight without fittings?
    Is "smooth" frictionless? There is a tool for real duct calculations. Get a free one at http://www.crownproductsco.com/freeductulator.htm
    What kind of velocity is your target?
    See if http://www.engineeringtoolbox.com/du...ons-d_883.html helps you.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  3. #3
    Join Date
    Sep 2011
    Posts
    2
    Hi Lynn,

    Many thanks for those pointers.

    The reason I need this is that we're installing new ducting in a suspended ceiling (for a new ventilation system), however the architecture of the ceiling is not uniform and there are various obstacles to go around. If we were to use standard round ducting I would be able to use manufacturer supplied data to measure static pressure for the different duct sizes and different volumes to figure out the overall static pressure in the whole system.

    However, to get around the problems in our suspended ceiling, we're going for custom-made rectangular ducting. The manufacturer is able to make the size to our specification but isn't able to tell me what the static pressure would be.

    I'm only looking for an estimate, just to make sure we're not overleading the machine.

  4. #4
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    The ductulator are great tools for what you are doing.
    Many show the duct fitting pressure drop information on the backside.
    Good luck.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  5. #5
    Join Date
    Aug 2011
    Location
    Kingston, Ontario
    Posts
    207
    Quote Originally Posted by amrs View Post
    Hello,

    I was hoping for a formula to help me calculate static pressure in custom-made (smooth metal) ventilation ducting, given the following information:

    1. Length of duct in meters
    2. Area of cross-section in meters squared
    3. Air flow in meters cubed per hour

    Any pointers would be greatly appreciated!

    amrs
    If you do a Google search for static pressure calculator, you should come up with a few spreadsheets. Here are some:
    http://www.bry-air.com/tech-center/r...c/default.html

    http://www.captiveaire.com/CATALOGCONTENT/DUCTWORK/DOC/STATIC PRESSURE CALCULATOR.XLS

    There are methods of calculating equivalent diameter of rectangular ducts. For example:

    http://www.hvac-toolbox.com/equivale...ter-d_443.html

    I used the captive air one to check our ductwork - easy enough to use.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event