POLL, Nitrox tank use and analyze

[Rainer]

Please cite all these diving accidents that involve divers using others' cylinders that have clearly marked contents labels. Hmmm.

As one poster just mentioned above, there are divers willing to ignore even those nitrox bumper stickers. Placing *your* hope in such stickers is clearly flawed given reality.

If you want to truly help new (shoot, all) divers, OW should emphasize analyzing and labeling ALL cylinders. That's really the only fool-proof safety solution. EVERY diver should know what he's breathing. There's always a chance of being given the wrong gas...

You prevent dive accidents with "hope"?

I prefer to mitigate risks with more concrete solutions.

 

[RTee]

#1 reason of diving accidents has got to be divers breathing the wrong gas. Failing to analyze your mix is an invitation for a demonstration of Darwinism.

Not that I want to hijack the thread but I am far from convinced that it is the #1 cause of diving accidents. Probably the topic of another tread (unless one already exist on statistics of diving accidents). However, I do agree that one is one too many especially when it is preventable.

Having said that, here is my take on markings (...and I am not GUE/Fundie/DIR certified)...I do not intend to change the way I mark my tanks (see my previous post) and turn them into XMas trees or rear car bumper material as I can, and do, exercise physical control over my own diving tanks whenever and wherever I go diving.

 

[AfterDark]

Not that I want to hijack the thread but I am far from convinced that it is the #1 cause of diving accidents. Probably the topic of another tread (unless one already exist on statistics of diving accidents). However, I do agree that one is one too many especially when it is preventable.

I'm with you. IMO the #1 reason for diving accidents is cranium rectal inversion.
Look deep enough and you'll find at least one person was afflicted.

 

[lowviz]

...//.... OW should emphasize analyzing and labeling ALL cylinders. That's really the only fool-proof safety solution. EVERY diver should know what he's breathing. There's always a chance of being given the wrong gas...

Not such a bad idea.

All agencies should require their OW students to be trained in the proper use of an O2 analyzer, have them analyze a cylinder, and tell them why. Should take about 10 minutes per student. Some will continue to analyze, others will not. However, all will have heard the message. Informed choice.

 

[Akimbo]

#1 reason of diving accidents has got to be divers breathing the wrong gas....

I concur that analyzing gas is prudent, but I don’t understand your assertion. As you saying that delivering Nitrox levels that are grossly too high is common enough to make it the #1 cause of diving accidents? From all I have read, confirmed oxygen toxicity hits in the water are extremely rare. On the other end, using a mix too lean, the risk is greater occurrence of decompression hits. Statistically, DCS is nowhere near a leading cause of injury.

Very few commercial Nitrox stations are capable of delivering a mix below 21%, though Trimix stations are. Mixes below 21% enters much more hazardous territory due to the rapid and symptomless nature of hypoxia and anoxia. I have to agree with RTee and AfterDark. Complacency rather ignorance is the root cause of most diving accidents.

 

[Adobo]

Please cite all these diving accidents that involve divers using others' cylinders that have clearly marked contents labels. Hmmm.

As one poster just mentioned above, there are divers willing to ignore even those nitrox bumper stickers. Placing *your* hope in such stickers is clearly flawed given reality.

If you want to truly help new (shoot, all) divers, OW should emphasize analyzing and labeling ALL cylinders. That's really the only fool-proof safety solution. EVERY diver should know what he's breathing. There's always a chance of being given the wrong gas...

In thinking about this, the only valid scenario I could come up with where an OW diver picks up someone else's tanks is one where the OW diver picks up the GUE diver's single backgas tank. In a single tank, the GUE diver will only have 32% (if following agency recommendations) or air (if not following agency recommendations) in that tank. So the only problem the OW diver will have in this scenario is if exceeds the MOD of 32% (111ft). And its not clear by how much and for how long the OW diver will have to exceed 111ft before O2 toxicity issues start to arise.

In my opinion, the bigger concern in the above scenario is an OW diver with limited knowledge going past 111ft in the first place. I hear about divers running into narcosis and gas management issues but I can't recall the last time I have heard/read about an OW diver exceeding MOD because he grabbed someone else's tank.

There is this other scenario where the OW diver picks up a GUE diver's deco bottle. In this case, the OW diver could run into O2 toxicity issues while being well within recreational diving depths.

In my opinion, this scenario is pretty much absurd for the following reasons:
- I would argue that it is a rare event when a GUE diver goes on an open recreational boat and brings deco bottles. In fact, I am curious to hear about any instance when someone has actually seen this happen.
- All GUE diver's deco/stage bottles that I have seen are rigged as such. If you as OW diver where to mistakenly pick up a deco bottle that has "70" sticker on it and a has deco bottle rigging and don't think to yourself that something is wrong, then I would say that it is Darwin stepping in.
- All GUE diver's deco/stage bottles that I have seen have been configured with DIN valves. An OW diver picking up a bottle, with a "70" sticker and deco bottle rigging and not thinking that were was something strange, will likely have not gone through the thought process to come to the conclusion that purchasing a DIN regulator is the way to go. I don't know what the situation is like in most places but everywhere I have been, yoke regulators have been the standard.

I could be wrong of course, but I am interested to hear about the "real world" scenarios.

 

[Mossman]

In thinking about this, the only valid scenario I could come up with where an OW diver picks up someone else's tanks is one where the OW diver picks up the GUE diver's single backgas tank. In a single tank, the GUE diver will only have 32% (if following agency recommendations) or air (if not following agency recommendations) in that tank. So the only problem the OW diver will have in this scenario is if exceeds the MOD of 32% (111ft). And its not clear by how much and for how long the OW diver will have to exceed 111ft before O2 toxicity issues start to arise.

That's an MOD based on 1.4, which is ultra-conservative. Using an MOD of 130' gives you 1.6, a number originally considered as the high end and coincidentally the "limit" for recreational diving in the U.S. Unless it's a snowy Tuesday in August, that OW diver should be able to get 45 minutes at 130' on your tank of 32% before venturing into a real danger zone for ox toxing, at which point that OW diver should be far more concerned about the near certainty of severe DCS by exceeding the NDL for that depth by about 30 minutes.

 

[DevonDiver]

Not such a bad idea.

All agencies should require their OW students to be trained in the proper use of an O2 analyzer, have them analyze a cylinder, and tell them why. Should take about 10 minutes per student. Some will continue to analyze, others will not. However, all will have heard the message. Informed choice.

Why not add rescue skills also.. and deco skills.... treble the price of the course and make it last longer than anyone spends on vacation?

There simply is no need to introduce nitrox at entry level. It's a minority issue, when you consider the full scope of the diving community.

Please cite all these diving accidents that involve divers using others' cylinders that have clearly marked contents labels. Hmmm.

Been taking lessons from Halemano on how to deflect a discussion when you can't directly answer the issues raised?

As one poster just mentioned above, there are divers willing to ignore even those nitrox bumper stickers. Placing *your* hope in such stickers is clearly flawed given reality.

Not really. I see it as a reasonable mitigation of risk. It's a .50c sticker.

All divers are educated about what that sticker means. They are not aall educated about what MOD means.

If you want to truly help new (shoot, all) divers, OW should emphasize analyzing and labeling ALL cylinders. That's really the only fool-proof safety solution. EVERY diver should know what he's breathing. There's always a chance of being given the wrong gas...

Nice theory. Absolutely absurd given the realities of most of the scuba industry though.

 

[Rainer]

Been taking lessons from Halemano on how to deflect a discussion when you can't directly answer the issues raised?

So just to be clear, you don't know of a SINGLE accident due to the cause I listed? Not one?

Not really. I see it as a reasonable mitigation of risk. It's a .50c sticker.

A sticker doesn't mitigate risk. Education does.

All divers are educated about what that sticker means. They are not aall educated about what MOD means.

Are you kidding? That's obviously FALSE given the anectodes in this very thread! I certainly wasn't taught what a nitrox sticker meant in OW. I doubt 5% of divers coming out of OW know what it means. What I did know coming out of OW is that I shouldn't grab random people's cylinders and that if I saw a contents label at the crown indicating numbers I didn't understand (gas contents), a date, and initials that weren't mine, I wouldn't dive it! If your students would, you're failing them. Every GUE diver is marking all that info on his cylinder. Another (half cent???) sticker isn't needed (as demonstrated by the lack of accidents due to this very issue).

Nice theory. Absolutely absurd given the realities of most of the scuba industry though.

Yes, asking divers to be responsible for the gas they breathe is just a "nice theory". And *I* am the one who doesn't care about diver safety?!

 

[DevonDiver]

So just to be clear, you don't know of a SINGLE accident due to the cause I listed? Not one?

My going rate for contract research work is $100 an hour. You can pay via Paypal or bank transfer. Just tell me how many years worth of accident reports you'd like me to trawl through and I'll give you a quote for approximate time/cost.

If, however, you're just trying to make a point that you don't feel that there is any risk of accidental tank usage, then fair enough. That's a viewpoint. My viewpoint differs. We work and dive in very different locations, with very different divers. I judge my views on the basis of what I see every day, as do you.

Again, it is my opinion, that when considering a globally applied protocol, you have to consider the lowest common denominator - that denominator being (IMHO) the cattle boat tourist operations evident throughout the tropics.

A sticker doesn't mitigate risk. Education does.

Which is why the vast majority of the dive agencies educate about the stickers.

One minor agency doesn't. It prefers to educate more completely - providing full training in nitrox.

Nothing wrong with that, but it is not reflective of the general industry stance.

I certainly wasn't taught what a nitrox sticker meant in OW.

What agency did you train with?

I doubt 5% of divers coming out of OW know what it means.

All of mine do. I know that because it is featured in the manual quizzes, knowledge reviews and the exam they have to pass.

I suspect most instructors for PADI and SSI would also share that certainty - as they use the same manuals, quizzes and exams with their students.

Statistically, that'll be most of the industry then....

What I did know coming out of OW is that I shouldn't grab random people's cylinders and that if I saw a contents label at the crown indicating numbers I didn't understand (gas contents), a date, and initials that weren't mine, I wouldn't dive it!

That might be relevant to your specific diving circumstances....very relevant to what I imagine most US diving is like... divers on charters, using their own cylinders and their own kit.

The vast majority of qualified divers don't own their own cylinders. They get on a boat, get handed a crate of equipment and pointed in the direction of a line of cylinders on a boat. Rental cylinders. Rental kit. Busy boat. Busy dive staff. Accidents waiting to happen.

As I said...I'm basing my perspectives on the lowest common denominator globally... mass market holiday diving.

I'm not defending those diving operations (or want the discussion to go off-topic into a debate about their qualities) - I'm just pointing out the reality of how diving happens. Maybe you never experienced that. If so, you are lucky.

If your students would, you're failing them. Every GUE diver is marking all that info on his cylinder. Another (half cent???) sticker isn't needed (as demonstrated by the lack of accidents due to this very issue).

Firstly.. I'm not anti-GUE/DIR. Let's be clear about that.

However, I do feel that some GUE policies are based on wishful thinking. Yes, it'd be great to revolutionize the dive industry - to make all agency courses much more comprehensive. But that's not going to happen... the majority of potential divers want a McDiving course. Only afterwards may they refine their views and demand more.

GUE sets great standards. Amongst the GUE community those standards work well - because of a common high standard of training and education. However, amongst the wider diving community, those standards are a liability.

If you think that any of the major agencies will change their protocols or course syllabus, because of anything that GUE say or do or teach, then you're back into wishful thinking again.

...and btw... we're not talking about my students. Global lowest common denominators remember?

Yes, asking divers to be responsible for the gas they breathe is just a "nice theory". And *I* am the one who doesn't care about diver safety?!

You're the one who thinks the dive industry revolves around GUE. News for you... it doesn't. Most divers have never even heard of the agency, let alone what it trains.

Likewise, most divers don't have a clue what nitrox is. Really... when you consider the whole industry...and all the people with scuba certifications... the amount of nitrox training is still statistically small.

I may be playing Devil's Advocate here.... but I'm the one considering the reality of the 'big picture'...and not basing an argument around my own limited perceptions of the dive industry.