Nitrox course. What's the point?

[Belzelbub]

Question for the OP, if you analyze your gas and the result is 32.4%, what value do you use as an input to your computer? What if it is 32.7%? Why?

Good question. Interestingly, this was not one that I recall being covered during my Nitrox course. I do know how to handle those, but I didn’t get it from the course. At least not directly.

 

[OTF]

+/- 1% doesn't really matter for the sake of MOD or nitrogen calculation and is well within the margin of error for most analyzers anyway so don't sweat 1% either way. Round to the nearest and go diving.

Not riding the edge of your MOD and adding a few minutes of extra hangtime at the end will give you far more of a safety buffer than agonizing over how to round 1% of your FO2.

 

[Belzelbub]

I am not sure I understand the question. I have never done it before so I assume that you mean you can’t enter the exact value, that some computers can handle decimals.

I’d say that’s probably most computers. All that I’ve used only have the ability to enter the mix in whole numbers.

Theoretically, if it was the case, I would be conservative and use the next digit up for the sake of MOD. However, for NDL and computer entry, that should be the other way around so I will round down. I need my computer to calculate the nitrogen exposure. MOD, I can deal with it myself.

Correct. Though in most cases unless you are pushing the limits, it won’t matter. Sounds like you have a good grasp on most of what you will learn. Unfortunately, I would not apply that to most divers. Several of the certified divers in the Nitrox class I took probably shouldn’t have been certified in OW in the first place based on their questions.

 

[Divin'Papaw]

All I dive is Nitrox. Air is an awful gas for diving. It either doesn’t have enough oxygen or too much nitrogen depending upon depth. I put air in my pony bottles and only because I occasionally use them to fill tires or as a blower.

Getting Nitrox certified was my most valuable cert beyond OW.

The point of the course is to teach you to use Nitrox safely. It also grants you the card you need to get fills & rent Nitrox tanks which most shops require.

 

[rick00001967]

it is possible the instructor just certified you for both courses with TDI.

 

[tursiops]

Dakota's triangle?

Dalton?

 

[Dody]

By the way. I have never asked. What does OP mean?

 

[rhwestfall]

Dalton?

Yep, see post #31...

 

[Divin'Papaw]

By the way. I have never asked. What does OP mean?

Original Post or Original Poster depending upon the context.

 

[David Novo]

I am not sure I understand the question. I have never done it before so I assume that you mean you can’t enter the exact value, that some computers can handle decimals. Theoretically, if it was the case, I would be conservative and use the next digit up for the sake of MOD. However, for NDL and computer entry, that should be the other way around so I will round down. I need my computer to calculate the nitrogen exposure. MOD, I can deal with it myself.

Good answer. I would read also the computer instructions as in some you should always round down and the computer uses that value for NDL calculations and the input + 1pp for MOD calculations.

+/- 1% doesn't really matter for the sake of MOD or nitrogen calculation and is well within the margin of error for most analyzers anyway so don't sweat 1% either way. Round to the nearest and go diving.

Not riding the edge of your MOD and adding a few minutes of extra hangtime at the end will give you far more of a safety buffer than agonizing over how to round 1% of your FO2.

Rounding to the nearest can be a nuissance, without any need for it.
For example, if you are going to dive to 30m and you round up 34.5%, a computer that calculates as the one I mentioned above is going to compute a MOD of 28.9m (@ ppO2 = 1.4) and start beeping for no reason.