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    Luke Durkin

    I'm having trouble finding much good as well.  My Ballast 4.0 book isn't helpful.  Just googling around it seems like it's a matter of finding out the CFM (cubic feet per minute) needed then using a chart.  I can't find much about how to get the CFM it seems complicated so I'm guessing that's something we aren't going to be expected to figure out.  The following link was kind of helpful, but probably more complicated than what we'd be tested on.  
    http://www.johnrwhite.net/three%20steps%20to%20duct%20sizing.htm

    Here are some examples of sizing charts I found via google.

    http://faculty-legacy.arch.tamu.edu/jbryant/teaching/COSC325/Downloads/Low%20-%20Medium%20Velocity%20Duct%20Sizing%20Chart.jpg
    http://2.bp.blogspot.com/-lAXhq4qQs28/TsDV3sh-p7I/AAAAAAAAAME/PWc88_8FmYc/s1600/DuctChart.gif
    http://energy-models.com/sites/all/files/advanced-pages-31043/duct-sizing-charts-tables-1.png

     

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    ANGELA FERRIGAN

    Luke, thanks for the info.  I think the charts and 'three steps' website are a good start, but it would be great if someone had a resource with a practice exam question. Seeing the actual numbers plugged into the formula and how that applies to the chart(s) would be really helpful. There are several comments in the PPD and PDD thread suggest that we should study duct sizing. I'm going to post something under one or 2 of those threads and see if they can offer any advice.

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    Anson Nickel

    Hi Angela,

    While duct sizing is interesting (.....), I don't think it'll be a huge component of either PPD or PDD tests. If anything, you'll probably see something like a ceiling clearance coordination issue, rather than a specific sizing due to room size or any other mechanical requirements.

    I'd recommend understanding the basic concepts of mechanical design (Air Unit -> big trunk -> small branch -> distribution, round = more air efficient than square, square more air efficient than rectangular) and what the main differences are between air/water, air/air, and other systems.

    These exams try to test you on what a typical architect might need to know. Specific duct sizes and how to get them don't usually fall into that category. 

    Best,
    Anson 

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    ANGELA FERRIGAN

    Good point, Anson. I just saw it listed as a study item in previous posts and thought I'd look into it. I think you're right though...it might be too in depth to actually be on this exam.

  • Avatar
    Anson Nickel

    As a follow-up, I've found a good rule of thumb is if the information you are studying can be found via large tables or excessive formulae, then that info will either 1) not be on the test or 2) will be presented on the test as an excerpt.

    Of course, various tables do require knowing fully (occupancy charts, construction types, etc) but in general, steel beam charts, psychrometric charts, ductolator numbers, etc need to be understood only in the general sense.

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    Luke Durkin

    I agree for PPD.  The PPD is about selecting systems, so understanding square/rectangular ducts vs circular ducts is a great example of something to know.  PDD is generally about sizing things.  For PDD I think it's about the same as structural, understand the formulas provided, then know the terms & units, in this case, CFM, in structural, Section Modulus, S, and Moment of Inertia, I.

    I'd also look at what the graphic vignettes are from 4.0.  My thinking is that if it was important enough to have a graphic vignette about it, odds are you'll get a question or possibly multiple questions about it in 5.0.

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