Nitrox class - no dives/dives?

[Germie]

To obtain the NAUI "Enriched Air Diver" certification card one must complete 2 dives using Nitrox after analyzing and recording the gas mixture.



-Z

That is easy, just analize AIR as it is nitrox. LOL. I used this when I had to proof 10 nitrox dives in the last year (I own a rebreather So have my own real time nitroxmixing machine and analyser.)

 

[Addicted2H2O]

I did my Nitrox through NAUI and they actually had two levels of certification. Nitrox Certified meant you'd taken the class but hadn't done the two required dives. Nitrox Diver (which is what I ended up with anyway even before I did the dives) meant you'd completed the required dives. Personally I think doing the dives should be a requirement so you can prove you can analyze your own mix and show that you know what your'e doing. Additionally, it would show you can plan said dives using Nitrox tables.

And now that I've been through the course and have the certification, I despise calling it "nitrox" because technically the air we breathe can be classified as nitrox. I prefer EAN at this point. Picky? Yeah....but accurate.

 

[tursiops]

And now that I've been through the course and have the certification, I despise calling it "nitrox" because technically the air we breathe can be classified as nitrox. I prefer EAN at this point. Picky? Yeah....but accurate.

Or, even better, call it deriched nitrogen, since that is what confers the benefits.

 

[Lorenzoid]

Even assuming the dives are required rather than optional, I just don't think it's a problem for most people--not enough of a problem to motivate the agency to drop the requirement. If you're the typical vacation diver--not Marie--you can do the written work online and finish up the course the first day you arrive at your destination, including dives. Most people who take the Nitrox course are newer divers, and it's not like they are in urgent need of a fill so they can go dive on their own somewhere.

 

[Photo Girl]

The nitrox course offered by the dive shop here (PADI) is classroom only.

I need to find time to take it.

 

[Barnaby'sDad]

My OW dives three and four doubled as Nitrox dives. No additional dives were required to get my OW and Nitrox cards (NAUI).

 

[Charles2]

My certification was through NAUI many, many years ago. I did the two required dives, using Nitrox, while doing other training. My certification reads "EANx Diver".

One of my grandsons just completed his NAUI training in the last few months. He did not have to complete any nitrox dives. His certification reads "Nitrox Diver".

Neither of us have any issues getting a nitrox fill.

Although oxygen enriched air, when used properly, is rather benign, I can see where someone might be a bit apprehensive when using it for the first time ever. In that case, a dive or two with an instructor (or competent buddy) might be appropriate.

Bragging a little, my instructor, Peter Oliver, was the principle author of the NAUI Nitrox Diver manual.

 

[boulderjohn]

I took the PADI Computer Nitrox class, and don't remember doing any calculations for the test. But after going back and learning what PADI didn't teach me, the things I wish PADI taught be better would be the equations for MOD, and the NOAA O2 exposure tables.

As Tursiops earlier, the PADI nitrox course I took years ago required all sorts of calculations. It was pretty tough. Nearly none of that is in the course today. I will address your two points and add more.

1. If you are using a computer, your computer will give you the MOD. Not only that, if you are diving at altitude, computers will adjust the MOD for altitude. (More on that later.)

2. The PADI course used to have long term O2 exposure tables as part of the course. The only question I missed on the 50 question test involved using that table. One thing I learned from that class was that to get into trouble on that table, you had to be doing a really, really serious set of dives. But that is not all. According to an email I go from PADI earlier this year, research after that indicated that if you are diving at the 1.4 standard, you can pretty much dive all day without a problem. That table was thus teaching something that was simply not necessary. Not only that, I learned not long ago that the NOAA O2 exposure tables is pretty much a wild guess--there was almost no science behind it when it was created.

3. Several years after getting that complex nitrox certification, I got certified as a DM, and I had to learn all the gas laws for that. I worked hard, and I got to know them well. I then did a fun dive trip with several people associated with the dive shop for which I was a DM, and we were diving nitrox at altitude. When we were talking about MODs, it suddenly occurred to me that we were diving at altitude--did we use the sea level MOD, or an adjusted MOD? We decided it had to be adjusted, but this had never occurred to any of the dive professionals in our group. We decided that we had to use the altitude adjustment table used for dive planning, meaning the 85 foot dive we were planning at the altitude needed to be planned as a 108 foot dive. We could therefore not dive with anything richer than 32%.

So that is what a group of highly trained professionals, including two nitrox instructors, decided, and we were dead wrong. The MOD for 32% at that altitude is 120 feet. We could have dived 40% safely there. Our calculations took us in the wrong direction--the MOD goes up as you gain altitude, not down. With all of our training, we did not know how to apply those gas laws we had all learned so thoroughly. In other words, people who rely on remembering and using that training are all too likely to make a mistake, and they are much better off looking things up.

I dive at that altitude regularly these days, going to depths like 280 feet when I do. Knowing the MOD is important to me. I therefore created a table for that altitude, and I do what every other diver does--I consult the table when planning a dive. During the dive itself, my computer tells me constantly what my partial pressure is during the dive, and it is adjusted for altitude.

 

[tursiops]

I also found that the equations to work out theoretical depth at altitude and the equivalent air depth for nitrox were the same equations....such that the results could cancel out. For any given altitude, there is a nitrox percentage such that the theoretical depth is the same as the actual depth. I used to dive at Mt Storm in WV a lot, and at that altitude the magic nitrox percentage was 26%, as I remember.

 

[boulderjohn]

Here is the use of math to calculate MOD at altitude. I will use 6000 feet, with an ATA of 0.8 to make the calculations easier. Let's find the MOD for 32% at that atmospheric pressure with a PPg of 1.4.

PPg = FG X P
1.4 = .32 X P
P = 4.375​

The pressure for that MOD will be the same anywhere. We just have to convert that pressure to depth.

1. At sea level, diving in salt water, with 33 feet equaling one atmosphere of pressure.

4.375 - 1 ATA = 3.375
3.375 X 33 = 111.375 feet
​

2. At 6,000 foot, diving in freshwater, with 34 feet equaling one atmosphere of pressure.

4.375 - 0.8 ATA = 3.575
3.575 X 34 = 121.55
​