Nitrox class

[oldschoolto]

Well, with a few exceptions I agree with you. Calibrating the analyzer is pretty important.....and watching people at dive resorts it is clear many do not have a clue about calibration. Turning on the valve just a bit and not too much is pretty important; depending on the analyzer too much gas flow can blow out the sensor or at least give a reading that is way too high. Rock bottom is the term for something else....I think you mean Maximum Operating Depth.

Maybe the problem is that people think it is so trivial that they stop thinkng.

In theory you need to check a tester before every check... But, In the real world... If I take tester, Any tester off the shelf and it gives me the reading I believe it should, I'm good... If I put a volt meter on a 6 volt battery and the meter reads 6.01 good... If it reads 22volts, Well I may need to look at it.. If I hook up a 32% nitrox tank and I get 31.99% good... If I get 42% I'm going to check that out.. But let's face the facts... If they are filling from banked nitrox at 32% at a dive shop you'll be getting 32% nitrox... If they are blending, that's a whole new ball game...

Jim...

And sorry you don't like my " Rock bottom " term...

 

[NAM001]

In regards to comments about nitrox and advanced nitrox being the same. I suspect that the nitrox class was probably over taught. The advanced IMO is much more important to do the dive with the gas as it has shallow mods. basic nitrox should by this time should be a pretty simple and brief course. The largest meat being the tank checkout and getting your computer set for the correct FO2. The rest is more or less primer for the advanced course. My wife is going to take a nitrox course with a shop that probably does not have nitrox in the shop. I will have to provide 2 tanks of nitrox for her to test. I may just give them one with 40% in it at 1500 psi and have them top off with air a bit for the second tank check.

 

[Johanan]

I suspect that the nitrox class was probably over taught.

Quite possible, given the present curricula. OTOH, I would see more sense to teach all the EAN calculations 0-100% + how to use the analyser in one Nitrox course. Gas switches, use of stages and setting up the computer for multiple gases could be included in the Deco Procedures course with no extra charge. Advanced Nitrox would be superfluous. I mean, there is not enough substance in the EAN topic for two consecutive courses.

 

[tursiops]

Quite possible, given the present curricula. OTOH, I would see more sense to teach all the EAN calculations 0-100% + how to use the analyser in one Nitrox course. Gas switches, use of stages and setting up the computer for multiple gases could be included in the Deco Procedures course with no extra charge. Advanced Nitrox would be superfluous. I mean, there is not enough substance in the EAN topic for two consecutive courses.

It is reasonable to ask the newer, less experienced divers to learn something about Nitrox (how to use it safely) without going into the full machinery of higher percentage O2, stages, etc. In a way, the current begining nitrox courses are a carryover from when the classes had much more material in them because it was felt that to be safe, you needed to know all that stuff. Clearly, you don't. So the courses have backed off on content but the course and certification and costs (!) remain.

I'd like to see the beginning Nitrox be an optional endorsement on the AOW card...and treated as some classroom time and hands-on-analyzer time during the class. So you'd end up with an AOW card or an AOW/N card. Very small additional cost, very little additional time. You'd also need to carry around only one card.

 

[oldschoolto]

^^^^ This makes a lot of sense ^^^

 

[boulderjohn]

Don't know anything about SSI and TDI. But there is day and night differences between PADI's Basic Nitrox and IANTD's Adv Nitrox. The Adv Nitrox includes 50% deco mix for light deco with a backmount twin set throw in as well. You can get away with a single tank with H-valve as alternative. Whatever it is, two independent 1st stages are required for the course.

There is an important difference between recreational nitrox and technical nitrox classes, and that difference translates into how the classes are taught.

Recreational nitrox limits divers to 40%, and that limit does not provide any real problems for the recreational diver--40% us all you need at the depths at which it can be used, and the NDLs for air at the shallower depths are so long that nitrox provides little real benefit. The benefit of the higher percentages allowed in technical nitrox courses is to be found in its use during decompression dives. That means the diver will need to carry at least one additional tank for that higher mix. So that is the main instructional difference. The recreational nitrox user will have only one tank, will not be making and gas switches, and will not be doing mandatory decompression stops. That makes doing any dives unnecessary; you learn nothing by doing them. In contrast, all of that will be new to the technical nitrox student, so there is a significant skill portion to the class.

The academic portions of the classes, though, are not that much different. The academic material related to nitrox in an Advanced Nitrox class is not much different from a recreational nitrox class. The TDI program allows the Advanced Nitrox course and the Decompression Procedures course to be taught as if they were one course, and in my view, it is almost foolish to do it otherwise. The courses are much better when the instructor is allowed to bring decompression skills from the DP course into the earlier dives for the AN course. I have never had to teach the AN class by itself, and I think I would feel hamstrung in my planning by such a limitation.

With PADI, the instructor MUST merge the advanced nitrox instruction and the decompression instruction. There is no Advanced Nitrox course by itself in the PADI program--learning to use (and being certified for) higher oxygen mixes is integrated into the Tec 40, 45, and 50 decompression diving courses. The students start using higher mixes right away in Tec 40 and then can use 100% oxygen for deco in Tec 45. They move on to using two decompression gases in Tec 50.

 

[IVC]

I did my Nitrox with PADI immediately after OW. It doesn't require dives because there is nothing to do in the water once the mix is analyzed properly and computer is set for the correct mix. It's a theory-based certificate where basic physics is applied to a gas mixuture, then it is linked to vast physiology studies of people exceeding various limits and (some of them) dying. So far so good.

The objection I have to some posts in this thread is trivializing Nitrox class to the physics part of it, as in "measure mixture, set up computer and forget about it." That's misleading and wrong. Without understanding the physiological aspect of using Nitrox, even if staying within limits, the class would be incomplete, bordering on negligent.

A big part of OW classes is not just about how to stay within table/computer limits, but also about what happens when those limits are exceeded. More importantly, OW teaches that the "boundaries" are not hard-science. The physics part is strict, but the effect on each individual is not. Some people get DCS even when diving within limits. Hence OW talks about contributing factors.

The same goes for Nitrox. Not teaching what happens when MOD is exceeded or how oxygen toxicity affects body, especially in light of convulsions reliably leading to drowning with no warning (the "twitching" is not a confirmed warning sign,) would be negligent. Especially, again, because the PPO2 limit of 1.4 (used to be 1.6) is arbitrary as in "works for most people." So are CNS limits.

My impression is that the PADI course was well designed because it provided more than just the basic information on how to analyze gas and use computer to figure out MOD. I wouldn't let anyone dive Nitrox unless they understood *why* it's dangerous to exceed the limits and *how* they are going to die if they do.

 

[NAM001]

For those that can handle that degree of training, I agree. I think nitrox has taken the same path as other training. Teach them only them minimum needed for the application. That means tank check ead , best mix, and mod calcs. IMO it makes no sence to teach the array of cns and otu calcs as a condition of passing basic nitrox. Now to teach it and not test it I would be ok with. As a prior educator you dont teach what you dont test. To teach cns and otu calcs and have nothing to relate it to in regards to the dives the student will be doing is wasted time. Students data dump what they do not use. I do think that there should be some time given to it so students know those things exist and why you avoid the diving that causes problems. So fo rme the class would say there is cns and otu's what it is why we track them and what the problems with it is. Then back it up with for the diving you will be doing you would have to dive 10 hours a day to reach these limits in 60 f' water and 5 hours in 120 ft water. (specifics are not important) and there fore the issues with prolonged exposure to high O2 concentrations does not normnally effect recreational divers that dive with in their limits. Then one more discusion of how long you would have to be on 40% at mod to have problems. Then what further things that divers do to not be effected at greater depths. Intro trimix and rebreathers as solution examples. That form on discussion reinforces additional dive planning.

Quite possible, given the present curricula. OTOH, I would see more sense to teach all the EAN calculations 0-100% + how to use the analyser in one Nitrox course. Gas switches, use of stages and setting up the computer for multiple gases could be included in the Deco Procedures course with no extra charge. Advanced Nitrox would be superfluous. I mean, there is not enough substance in the EAN topic for two consecutive courses.

 

[DiveNav]

SHaase,
at the end of the day there will be not too much of a difference between the SSI and PADI Nitrox course.

If you are interested we have created a nice "Introduction to Nitrox online class" (that costs $5.00) that should help you ace any official Nitrox course.

We also make (very) smart gas analyzer

 

[Centrals]

There is an important difference between recreational nitrox and technical nitrox classes, and that difference translates into how the classes are taught.

Recreational nitrox limits divers to 40%, and that limit does not provide any real problems for the recreational diver--40% us all you need at the depths at which it can be used, and the NDLs for air at the shallower depths are so long that nitrox provides little real benefit. The benefit of the higher percentages allowed in technical nitrox courses is to be found in its use during decompression dives. That means the diver will need to carry at least one additional tank for that higher mix. So that is the main instructional difference. The recreational nitrox user will have only one tank, will not be making and gas switches, and will not be doing mandatory decompression stops. That makes doing any dives unnecessary; you learn nothing by doing them. In contrast, all of that will be new to the technical nitrox student, so there is a significant skill portion to the class.

The academic portions of the classes, though, are not that much different. The academic material related to nitrox in an Advanced Nitrox class is not much different from a recreational nitrox class. The TDI program allows the Advanced Nitrox course and the Decompression Procedures course to be taught as if they were one course, and in my view, it is almost foolish to do it otherwise. The courses are much better when the instructor is allowed to bring decompression skills from the DP course into the earlier dives for the AN course. I have never had to teach the AN class by itself, and I think I would feel hamstrung in my planning by such a limitation.

With PADI, the instructor MUST merge the advanced nitrox instruction and the decompression instruction. There is no Advanced Nitrox course by itself in the PADI program--learning to use (and being certified for) higher oxygen mixes is integrated into the Tec 40, 45, and 50 decompression diving courses. The students start using higher mixes right away in Tec 40 and then can use 100% oxygen for deco in Tec 45. They move on to using two decompression gases in Tec 50.

My answer was meant to post #25. Would you like to comment on that post(#25)?