Is there any reason to do a Nitrox 'course'?

[Crass3000]

A nitrox class is pretty cheap and not very time intensive. If you want nitrox, why bother with not getting the card?

 

[tamas970]

Okay, trimix was a long shot, I agree. Completely different experience level and a fat wallet is needed.

Deco and "advanced" nitrox on the other hand shouldn't be overmystified.

There are very good reasons why making trimix available to typical recreational divers is a bad idea ... the most obvious being cost. If you're complaining about a $10 nitrox fill, imagine how you're gonna feel when you go get a 21/35 fill in a set of doubles and the bill comes to $80-$100. A more practical reason, however, is that helium ongasses and offgasses MUCH faster than nitrogen ... and people with questionable buoyancy control can bend themselves fairly easily breathing helium. It's "privileged for the Tec community" because it's generally assumed that by the time you get to that level you'll have solid buoyancy skills, and be able to hold the stops where and when the profile calls for it ... because you HAVE to. Blowing a safety stop on a recreational dive might increase the risk of DCS, but it generally doesn't result in a hit. Blowing a deco stop on trimix usually will. No dive shop in their right mind is going to risk that kind of liability on the assumption that a typical recreational diver will have either the chops or the self-discipline to manage mandatory stops.

From a practical perspective, once you start diving doubles and trimix, the cost of training is only the down-payment. A decent doubles rig ... with tanks, bands, and regulators ... will run you $1200 or more. Add in a deco bottle or two and a couple more regs and the cost of the trimix class starts looking rather insignificant compared to what it takes to dive that way.



I'll betchya they don't teach trimix, though. There's nothing magical about exceeding NDL ... as long as you have the gas and the discipline to honor your deco obligation.

Trimix is a whole 'nother issue ...

... Bob (Grateful Diver)

 

[Edward3c]

There is some variation between agencies, the BSAC and CMAS at least teaches deco for advanced rec divers... (cmas***, BSAC sports diver)

I'll betchya they don't teach trimix, though. There's nothing magical about exceeding NDL ... as long as you have the gas and the discipline to honor your deco obligation.

Trimix is a whole 'nother issue ...

... Bob (Grateful Diver)

BSAC do both open circuit and re-breather Trimix, see here.


Kind regards

 

[MXGratefulDiver]

BSAC do both open circuit and re-breather Trimix, see here.


Kind regards

Yes, of course they do ... but as it says right in the title of the page your link opens, that is Technical diving. Please re-read the context of the conversation ... tamas970 was suggesting teaching trimix at the recreational level. BSAC doesn't do that ... which is exactly my point.

... Bob (Grateful Diver)

 

[Dan Sumners]

Actually... I would swap the question around. For diving in the 0-30m range... I would pose the question: Is there any good reason NOT to dive nitrox?
If you follow air tables, you have extra buffer.
If you follow nitrox tables you can maximize bottomtime.

That's the conclusion I've come to - I just wanted to know if I would be able to get Nitrox fills without paying someone £100 to 'certify' that I know the things I know I know, but I do understand the issue from the point of view of the gas provider.

But seems there may be a difference between the US and elsewhere... can anyone else diving regularly in Europe share their experience; do you get asked for the card by gas providers?

 

[TSandM]

My Nitrox card is one of the only cards I have routinely had to produce on boats and in resorts. That's the value of the card.

The value of the class is something else, and as with so many other classes, depends on the instructor. My husband loves to teach Nitrox . . . but he includes a whole section on gas management in the class, on the theory that, since Nitrox pretty much removes NDLs as an issue within the first 100 feet, divers really need to know how to plan their gas supply so that they aren't unpleasantly surprised at depth. Students do comment along the lines of, "Why didn't anybody tell me this before?" And you won't find that information in searching on Nitrox alone.

 

[tamas970]

I am becoming regular in Croatia (has quite a few beautiful dive sites) - they do ask for the card. However, it can be get there a bit cheaper, around 100€. It also makes sense to use EANx there, 30+m deep, almost square dives are quite frequent - you have to optimize your mix to get reasonable bottom time. It is possible, that you have to limit yourself to EANx28 for the first dive to keep your O2 exposure under control.

 

[DivemasterDennis]

The reason to take a nitrox course is to learn to use the gas safely. It is important to learn about o2 partial pressures, and accumulations. I love diving nitrox, and am confident doing so. But I pay close attention to appropriate dive planning and maximum depth limits. That's is the reason to take a nitrox class. To be a safe nitrox diver.
DivemasterDennis

 

[DevonDiver]

They need to "Put Another Dollar In" to remain solvent. Why trimix and deco are privileged for the Tec community and not taught at even DM level? Simple dive-shop logistics and financial reasons.

I think that's overly cynical. The term 'tec' (or however you want to spell it) simply refers to an approach to diving, differentiated from 'rec' due the drawing of a hypothetical line at an obvious set of limits.

That differentiation is becoming increasingly 'gray', as the popularity of "tecreational" (a new term?) diving becomes more mainstream: normoxic trimix in recreational depths, sidemount and backmount doubles use for non-decompression diving, improved awareness of overhead (particularly cavern/cave) diving, the rising popularity of closed-circuit rebreather diving and accessibility to "non-technical" training in CCR etc

But why would trimix/deco be taught on a DM course? That course has a specific purpose - to develop dive leadership and instructional assistant competency. It isn't about developing the scope of diving activities. So why muddle it?

Of course, it profits better if you sell every bit of knowledge separately and issue separate cards at each level. More than that, it would be a serious investment for a dive shop to rent doubles & offer trimix as a routine

Agencies provide a core syllabus, along with optional training to cover specific niche interests. That's a common approach, regardless of whether the agency is 'commercial' or 'club' orientated.

Forcing every diver into doubles and breathing trimix is frankly a ludicrous proposition. The greater majority of divers have no inclination to progress into that diving niche, nor gain those capabilities. Neither do they have the budget (or desire to allocate a budget) to do that, should they otherwise simply want to progress their training. Those who do want that know where to find it.

There is some variation between agencies, the BSAC and CMAS at least teaches deco for advanced rec divers... (cmas***, BSAC sports diver)

I wasn't "taught" how to do Deco on the BSAC Sports Diver course. Yes, that level permits access to the full scope of the BSAC '88 tables, which include post-course progression (with eperience) into some very light non-accelerated deco, but there was no specific tuition on decompression procedures (accelerated or otherwise), specific equipment or contingency protocols.

I can't speak for CMAS, but it would be wrong to state that BSAC "taught deco" at Sports Diver level. They have a separate program for that (that is very much in line with other 'commercial' agencies') which encompasses accelerated deco and mixed-gas use at progressive depths.

Technical Diving - General - British Sub-Aqua Club

"BSAC have developed a full suite of technical courses, meeting the demand of divers to extend the range and scope of their diving."

 

[Sevenrider860]

PADI. My manual is long gone but I just stumbled across a thread from 2006 where a poster said that on page xxx of their 2004 edition manual that it said something to the effect of it's not safer in terms of DCS. (p.16-17 in the PADI Enriched Air Diver Manual Version 2.1) If someone has a recent manual and can post the relevant information, that'd be great.

I'm not arguing one way or the other. I'm just recalling what I was told.

My son just took his PADI Enriched Air Diver class last week. I am assuming this is the latest. Under "Enriched Air and Safety" - Page 4...

"Logically, if you make a given dive breathing enriched air, you finish with less dissolved nitrogen in in your body than if you had made the same dive using normal air. This is a good thing, however it would be too simplistic to state that when well within air limits, enriched air is "safer" than air. As you will see, higher oxygen levels create a potential hazard that hardly exists in air diving within recreational limits."

The next paragraph talks about breathing enriched air using an air computer and has the following sentence. "This may be attractive if you are subject to one or more of the factors that make decompression sickness (DCS) more likely."

So PADI does not come out and say it is "safer" as you are trading DCS risks for oxygen toxicity risks. But they certainly make statements that allow one to make their own conclusion with regards to the "benefits" of enriched air over air. If a diver is suspected of having a DCI emergency, the course of action is to put the diver on 100% O2 or other enriched air. It is certainly more "beneficial", but is it "safer"? I guess it depends on the specific diver. I have seen some with such poor buoyancy skills or situational awareness with respect to depth that a statement could be made that diving enriched air is more dangerous than air...for that diver.

---------- Post added June 12th, 2013 at 12:23 AM ----------

"

For similarly unlikely reasons they prohibit those under the age of 15 from using nitrox"​

The minimum age for PADI Enriched Air Diver is 12 years old. Probably because they understand the maths quickly.

Another agency offers "Recreational Trimix". Minimum age is 15 years old, be an Advanced Open Water diver, have taken the Nitrox Diver course (or take it concurrently) and have 15 logged dives.


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