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What Nitrox Calculations do you use?

Discussion in 'Basic Scuba' started by citykid, Sep 19, 2005.

  1. ScubaSixString

    ScubaSixString Solo Diver

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    I get the impression he is in class and thinks he needs to memorize the formulas. But it really isn't clear
     
  2. GQMedic

    GQMedic NAUI Instructor

    # of Dives: I'm a Fish!
    Location: SoCal. (Yeah, baybee)
    678
    2
    18
    Ummmm, okay. 1st, 1. Are you currently Nitrox Certified or are you currently taking a Nitrox Cert class? Inquiring minds wanna know..

    ETA:

    After planning out my dive, I've got firm idea of how far down MAX I'll go keeping with the 1.4 ATM rule, I do a little math and come up with BEST MIX. (I'm assuming you already know how to do this) After this, I do a little more math and come up with my MOD (Max Op Depth) Everything should jive, plugging in the numbers is easy stuff. When planning your dive, don't forget to plan for contingincies. I've an OceanX wheel, call me old fashioned, but I'd rather rely on the math. Conservative well planned out dives = Happy diver over and over again.

    Some divers have already posted some great replies. I don't think I can say anything more without trying to reinvent the wheel.
     
  3. StSomewhere

    StSomewhere Loggerhead Turtle

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    I've taken a page from someone else's K.I.S.S. playbook, and pretty much stick with EAN32. Its easy to find, has an appropriate MOD (for me, YMMV!) and I've pretty much memorized my Buhlman EAN32 tables for common depths, SI and RNTs.

    OTOH, I do like working the problems and have been known to run the numbers for ****s and grins. I agree with the above, if you know how the numbers are derived the formulas just "fall out".
     
  4. String

    String Master Instructor

    # of Dives: I just don't log dives
    Location: Grand Cayman
    8,509
    365
    83
    Unless i know im doing something more exciting i tend to keep my main tank full of 32% and my second tank of 36%.

    This works for most of my diving although i do occasionally have to vent out perfectly good 32% and replace with 27 or 28 if i find out we're actually doing some interesting diving.

    As a result i have the MODs and so on of 32 & 36 firmly embedded into my head. That said i do analyse every mix and then write a label for the tank at the same time (initials, date, % O2 and MOD at 1.4 and 1.6)

    As i said though i dont actually have any tables i can use with nitrox/EAD at the moment so its all done on computer or a rough guess off PC software.
     
  5. Jarrett

    Jarrett Solo Diver

    # of Dives: 50 - 99
    Location: DFW area
    760
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    Can you not just use a 32% mix and dive air tables? That was my plan. Or maybe like Christi mentioned. Set one computer to EAN32 and other to air, then monitoring O2 Tox loading on EAN32 compter and bottom time/nitrogen loading on the other. Seems like a good plan, is it not?
     
  6. Hickdive

    Hickdive Solo Diver

    # of Dives: 1,000 - 2,499
    Location: Glasgow, UK
    1,028
    653
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    Dalton's Triangle

    Pg
    -------------
    Fg | P

    or Pigs eat Figs and Peas.

    Cover the unknown to reveal the formula for calculating it.

    Pg is max ppO2, Fg is % of gas in mix as a decimal fraction and P is ambient pressure
     
  7. ScubaSixString

    ScubaSixString Solo Diver

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    That depends on what you're doing. I was going to dive the U-352 (115-120 ft) 2 weeks ago (visibility blew that one out :( ) and EAN32 would have put me over the 1.4 PO2

    Luckily, the shop banked 30 which was perfect....if only the sea had cooperated. The others diving with me aren't Nitrox certified, so i was going to dive EAN30 on air tables for the added safety margin.
     
  8. String

    String Master Instructor

    # of Dives: I just don't log dives
    Location: Grand Cayman
    8,509
    365
    83
    Nitrox on air tables is perfectly possible provided you manually track O2 tox. It does defeat one of the main purposes of nitrox though - longer no stop and shorter deco stops.
     
  9. ScubaSixString

    ScubaSixString Solo Diver

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    As i'm sure you are aware (and as the courses are now teaching), diving nitrox on air tables (provided you manually track oxygen loading) reduces the risk of DCI. That's what the books are calling the 3rd benefit of nitrox diving. But it does restrict the NDLs.
     
  10. String

    String Master Instructor

    # of Dives: I just don't log dives
    Location: Grand Cayman
    8,509
    365
    83
    Proven by DAN (2 years ago) to be such a small difference its statistically insignificant and below the noise floor.
     

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