what the different between using Nitrox and Normal Air to dive???

[Rich Keller]

rox, I would like to see that study if you can find it. The random effects do depend on your state of being at the time but the test is just an indicator of tolerance not a scientific determination. The people giving these tests do not claim to know as much as some of the people here but if you have a problem with O2 at depth this will show it. It is not to be chiseled in stone but it is cheap and simple way to find out if this is going to be a problem for the divers wanting to get into Nitrox. Is it possible that the reason this test is not mentioned is that it might deter people from taking the course and buying all the equipment that goes along with it?

 

[PfcAJ]

If you want to read that study, its in the post Rainer made.

Your tolerance test isn't a valid test, that's the moral of the story. It makes no sense to test people for tolerance to hyperbaric oxygen because there is HUGE intrasubject variability. You don't gain anything by testing. Passing the test once has nothing to do with passing it again, and failing it once has nothing to do with failing it again. Its a crapshoot.

Just because the Navy manual says something, that doesn't make it true. Blindly following something is one of the WORST things you can do.

 

[scubamama5]

 

[Cave Diver]

rox, I would like to see that study if you can find it. The random effects do depend on your state of being at the time but the test is just an indicator of tolerance not a scientific determination. The people giving these tests do not claim to know as much as some of the people here but if you have a problem with O2 at depth this will show it. It is not to be chiseled in stone but it is cheap and simple way to find out if this is going to be a problem for the divers wanting to get into Nitrox. Is it possible that the reason this test is not mentioned is that it might deter people from taking the course and buying all the equipment that goes along with it?

Two things.

1) The parameters you posted for the test are much higher than those experienced by a recreational diver. Failing that test has no bearing on how someone is going to react diving recreationally on Nitrox. Just because something works in the military doesn't mean it translates to civilian use.

2) Nitrox is not equipment intensive. Many of the same regs people use for air diving are compatible with up to 40% Nitrox. A little more care is needed to clean and maintain tanks, but it's not really that $$ intensive.

You're really trying to compare apples and oranges here.

 

[SC_Hoaty]

FWIW, took the course, and there was no O2 tolerance test.

 

[UCFKnightDiver]

Bottom line. Nitrox is a tool. Use for appropriate applications. A 30' quarry dive. Yep. You wasted your money. A 150' deco dive using 24-25% bottom mix and a 50% deco mix. Well worth the money.

If you don't want to pay for it, go buy a compressor, whip, and some J bottles of O2 and mix. I think you'll find the cost of supporting the tools needed to blend will offset several overpriced fills.

I disagree

 

[Cave Diver]

I disagree

Yikes! I missed that.

 

[UCFKnightDiver]

I disagree

To elaborate, I don't think nitrox is a safe gas for diving at that depth, I think trimix is a much more prudent gas choice!

 

[BKP]

I'm not a tech diver, so this may be a learning moment for me, but at 25% EAN that 616 mentioned, and a P02 of 1.4, wouldn't that allow for a max depth of 151, and if you push it to 1.6, a max depth of 178?

Again, it's not an area I play in, just curious...

 

[gypsyjim]

All I can think of, reading threw this thread, is a story one of my brothers told about the Navy.

He was civilian, scientist involved in the detecting of Ruskie subs (a long time back now). He had a presentation of some sort to the high brass boys, on the technology, and partway through his presentation an Admiral interrupted him to ask a question.

"Son," he said, "I can't help but notice that you are using Russian Navy Oceanographic depth charts. Why are you using Russian Navy charts and not US Navy depth charts?"

My brother explained that in their experience the Russian charts were more accurate, to which the Admiral replied, quite coldly:

"Son, I am an Admiral in the United State Navy. When you do a presentation to me, you will use US Navy depth charts."

He used this story to explain the difficulty the civilian tech boys had, getting the carreer brass to even consider a new concept or idea, or drop an out dated concept.

The navy takes a long time to accept new ideas. As an example, in the late 30's and early 40's the high brass was mostly certain the battleships would rule the sea, and flat tops, and air power were just good for protecting the real firepower that would dominate any future conflicts, the king of the seas, battleships.

Although I may have learned tonight that before I do any 700 ft dives I might need to look into testing my O2 tolerance?