Really Dumb Question

Morg_NZ

can anyone either pm to me or post a simple equation to work out the nitrogen contents of a loop at a particular depth on a spacific set point???

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dive2dive2000

Not sure I am understanding the question??? set point divided by ATA will equal PPO2 or PPN, No different than OC. Basic Nitrox formulas still apply. ATA and PP will always be related whether the loop is open, semi, or closed. Hope that helps. Have you taken any Nitrox courses?

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Martin

"but what's the fun of getting what you need, instead of what you want?"

diverrob

Set point divided by the ATA will give you the % O2 in the loop and then you subtract from 100 to get the N2 in the loop.

1.3/5ATA=.26X100= 26% O2 in the loop therfore.....

100-26%O2= 74%N2 in the loop

Rob

zmcave

just remember the Total Pressure of a gas is the sum of each individual gas Partial pressure.

PT= PPgas1 + PPgas2 + PPgasn ...

So, lets take air diluent. At surface and with a set point of 1.0 you have:
PT = 1 (atmosferic pressure)
PPO2 = 1.0 (as defined by setpoint)
PPN2 = PT - PPO2 = 0 (zero) ---> N2% is zero

now at depht:

PT = 3 (at 20 meters)
PPO2 = 1.0 (as defined by setpoint)
PPN2 = PT - PPO2 = 3 - 1 = 2 (two) ----> N2% = use dalton's or the T formula:

FN2 = PPN2 / Pressure = 2 / 3 = .66 ------> N2% = 66%

Just follow that to whatever depth and set point you need.

Zé.