PADI Nitrox Course Review

[oreocookie]

While I agree that PADI is often guilty of badly worded questions, I'm not really sure this is one of them. It asks for hazards of filling; the last 2 aren't hazards unless you don't analyze the tank before you dive it, which possibly makes them hazards of stupidity, not improper filling. It is a bit disappointing, though, that the course has been "simplified", though I remember noticing that they essentially told you how to calculate MOD in the e-learning course, though in a somewhat roundabout way that (now that I try to find it again) appears to be more of an example of how ppO2 changes with depth. Telling you to scroll through your computer to find MOD is pretty lame. I did learn something somewhat useful during the course though: the LDS I did the course through does custom blends (unless the bank weird mixes) since the tanks I had to analyze included a 32%, 28% and a 23% and a regular air just to make sure I'd notice (apparently the MOD of air is ~188ft).

 

[TMHeimer]

But TMH, neither being hungover nor being tired from a surface swim causes DCS at all. What causes DCS is nitrogen supersaturation in the human body, and the way tissues get supersaturated is by staying down too long or going too deep. No matter how hungover or tired a person is, s/he will not suffer from DCS without getting in the water on scuba and staying down too long or going too deep. Adding the word "main" to the question would not make those other answers any more incorrect than they already are. The important point that is being made by that question is that time at depth is what loads nitrogen into tissues of the human body.

Instead of fixating on how their egos "got bent" by getting an answer wrong, dive students should consider what doing the course contributes to their enjoyment of diving safely.

I recall learning the following may be factors in DCS due to their effect on circulation (how N is absorbed and off gassed): Cold, alcohol (some still in system if hungover?), exercising before diving (ei-long surface swim), smoking (Carbon Monoxide from smokes attaches to hemoglobin, not allowing Oxygen to do so), hot showers afterword, age. Obviously if you stay well within the NDL these things would hardly ever matter, if at all. Am I wrong that these are secondary causes?

I would assume that if you are right at the NDL or even slightly over it, these secondary causes may be determining factors.

 

[Quero]

You might think that it's splitting hairs in terms of word usage, but since you are advocating precision in wording things, let's be clear: predisposing factors and causes are not the same. All of the factors you name may predispose a diver towards being more susceptible to getting a DCS hit, but none of them will actually cause the hit. A diver will never take a hit simply by taking a hot shower or drinking alcohol or exercising, but a diver may take a hit without any of these factors coming into play if s/he dives too deep for too long. When you look at it from a cause and effect perspective, it's clear what causes DCS and what doesn't.

 

[DiveNav]

......As far as I can tell, one of the things most agencies are working toward is to take as much math as possible out of anything related to scuba......

What math is in a Nitrox class? I only see some arithmetics ... and not even a division

 

[NAM001]

i have to take exception to your 30 second course. I feel confident you do not actually do it in 30 seconds however, you general attitude appears to be that the stupid students cant handle such comples concepts so i will give them a hand full of rules and call it a day. I dont know how much teaching you have done but each course is a steppping stone to the nest level. of your pints "a" is a good, it is safety and just common sence, besides only you are responsible for your ultimate safety. "b" is a bad one. what about 27% 36% 40%. or does that require some math and knowing about ead and and the like. when moving on to trimix those concepts of ead and end need to be socond nature. "c" why there are deep diving and then tech stuff that will break that rule. not to mention 100 ft is not the right depth for other mixes, which they will never know because they dont know. "d" i wont go there. only teach computer....... this is a pass the buck of responsibility to the computer... If you die dont feel bad it was the computers fault not yours......because you did not know any different.

I truly hope i have missunderstood you position.

OP -- what is it you think you should know that you weren't taught?

In my PADI EAN class, I teach a "30 second Nitrox class" which, in my opinion, teaches a student what they need to know to use Nitrox.

a. Always analyze your own tank.

b. Only use 32%.

c. Stay above 100 feet.

d. Breathe.

And I can "teach" that in about 30 seconds. OK, what else does a recreational diver need to know?

But, back to your critique -- How does "improper filling" of a tank increase the risk of DCS? Perhaps you are overthinking the question?

I (unfortunately) teach the "computer only" PADI class -- but I also give my students the formulas to calculate MOD and EAD and have them work the problems. I have no idea why others won't/don't do this.

 

[A34735]

That's a good question...I think I was expecting, that by the end of the class, I would need to have demonstrated I could calculate MOD and no stop times for a given %age O2. If I were training, I would want to turn out people, who could at least mentally check their computer plan looked about right.

And the PADI Enriched Air Simulator tool is also wrong: If you set the Nitrox computer to 21% 02, the no stop times at 80ft are 11 mins (air computer) and 44 mins (Nitrox computer). Really?

Whilst I can understand they might be a little difference due to rounding errors, 4X? I don't think so....

Back to Q7:

If 'improper filling' put plain 21% O2 air into the tank, and I dived it (without analyzing it) thinking it was 32% or 36%, isn't there a risk the indicated no stop times will be falsely long? So I then load up excessively on nitrogen...

I think your approach of giving students the formulas is right, just puzzled why it isn't standard...

OP -- what is it you think you should know that you weren't taught?
But, back to your critique -- How does "improper filling" of a tank increase the risk of DCS? Perhaps you are overthinking the question?

I (unfortunately) teach the "computer only" PADI class -- but I also give my students the formulas to calculate MOD and EAD and have them work the problems. I have no idea why others won't/don't do this.

 

[A34735]

Does anyone gets their tanks filled at 'welding fill suppliers'?

I think one objective of the course is to '..find gaps in understanding and discuss topics further'. I think the objective of tests is to see if the information stuck and was comprehended.

I'm not proposing taking something simple and making it difficult. But courses where no one fails (at first attempt) can't be a good thing

A34735, it sounds to me like you are trying to justify your incorrect answer by complaining about the course materials and the instructional approach. Maybe what you need to do is to try to look at the course, the materials, and the teaching/learning process in a different way.

In fact, c and d are not correct answers to the question. Those are definite risks, but they're risks of using an improperly labeled or analysed blend, not risks of filling a tank improperly. The whole point of that question is to dissuade people from getting their own tanks filled at places like welding fill suppliers rather than at scuba fill stations, but maybe you missed that insight. It doesn't matter that some people get that question (or any question) wrong--I use any incorrect answer, such as they one you gave, as an opportunity to reinforce these important points. The objective of the test is not to pass or fail the candidate--the test is more like a diagnostic tool that allows both the student and the instructor to find gaps in understanding and to discuss the topics further.

There is nothing hard about diving Nitrox or learning to dive Nitrox at the recreational level. I fail to see why you want the course to artificially turn something that is easy into a weed-em-out-by-failing-their-sorry-asses sort of course, but if you are comparing today's scuba instruction with what was offered by BSAC decades ago, you will find virtually no course as militaristic and gung-ho macho as those courses used to be (and yes, even BSAC has gone "soft", if by "declining standards" you are parroting the "in the old days" mentality that so many spout here).

 

[Simon-]

That's a good question...I think I was expecting, that by the end of the class, I would need to have demonstrated I could calculate MOD and no stop times for a given %age O2. If I were training, I would want to turn out people, who could at least mentally check their computer plan looked about right.

And the PADI Enriched Air Simulator tool is also wrong: If you set the Nitrox computer to 21% 02, the no stop times at 80ft are 11 mins (air computer) and 44 mins (Nitrox computer). Really?

Whilst I can understand they might be a little difference due to rounding errors, 4X? I don't think so....

Back to Q7:

If 'improper filling' put plain 21% O2 air into the tank, and I dived it (without analyzing it) thinking it was 32% or 36%, isn't there a risk the indicated no stop times will be falsely long? So I then load up excessively on nitrogen...
I think your approach of giving students the formulas is right, just puzzled why it isn't standard...

It still isn't a hazard at filling. The hazard is at using. If you choose to dive without analysing, it's your mistake, not where it was filled.

Personally analyse and mark your own cylinders.

Incidently, any EAN course I teach, regardless if the student uses a computer or not, they learn the tables. Even if that means they learn the air RDP first. They can all work out their EAD's and MOD's very easily. My rationale for this; dive tables don't run out of batteries or flood

To me it sounds as though the instruction you received wasn't as comprehensive as it could have been.

 

[Steve50]

With a little interview ahead of time, you can skip courses that you can't fail, or, are overpriced..

 

[eternaljonah]

i did the nitrox course and feel that even though you pay to get a padi card, to show you know some where else. you also( and that most important) pay for the instructor. HE is the one giving you the knowledge. padi is just a tool for the instructor. if you have a good instructor he will make sure you know every thing you need. but if you have a salesman selling you a card then ?