POLL, Nitrox tank use and analyze

[Adobo]

I did not answer your poll but I would like to offer my perspective..

I am interpreting your question as, if you are diving a non-air nitrox mix, what do you do in terms of analysis?

I always analyze tanks at the dive shop and at the day of the dive. I don't see what benefit is to be had by not analyzing at the day of the dive.

Additionally, I don't ever really dive air. But if I did, I would also consider analyzing tanks that are supposedly filled with air if the dive shops fills anything else other than air.

 

[Rainer]

Yes, I agree, the cylinders really need to ALSO be analyzed the day of the dive (both as a second check and more importantly, because **** can happen between when you picked them up and when you dive them; e.g. stickers fall off, stickers get swapped, gas settles, etc).

All of our cylinders are labeled with date of analysis (which needs to match the dive date before the gas is breathed), initials of who analyzed it, and mix to one decimal place. Stages and deco bottles are also labeled with MOD in 3" letters (and also the word "OXYGEN" for O2).

To me, these seem like two fundamentally different approaches. Your approach checks to make sure that the tanks you are bringing to go diving that day have the mix that you expect them to have.

Whereas the other approach checks to make sure that at the dive shop, the tanks have the right mix.

In my case, I usually use two al80s in addition to my backgas. One al80 is used for 100ft and shallower. The other is used for 70ft and shallower. If I were to bring both of these tanks to the dive shop to be refilled after a day's worth of diving, it is conceivable that when i pick them up, I get the proper readings on the analyzer but then inadvertently put the analysis tape on the wrong tanks (put the 100ft analysis on the 70ft bottle and vice versa).

Now, in your approach, you should be able to pick up this mistake when either you or your wife does the analysis on the tanks on the day of the dive. In the other example, I am not sure what happens.

Also, I am not clear on what some agencies teach in terms of labeling stage/deco bottles. Maybe the labeling system is meant to catch this type of mistake also. Or maybe not.

 

[StuartT]

A couple of weeks ago one of my regular dive buddies wanted to swap his 2 steel 100's for my 2 steel 130's for a wreck dive he planned and wanted some additional gas. His tanks were marked 29% and although I didn't personally see them being analyzed I completely trust him plus he has his own analyzer which he told me he had just used prior to me swapping tanks with him.This was in addition to him seeing them analyzed at the lds that filled them for him. So I dived both tanks without actually analyzing them myself but felt comfortable diving them. Both my dives that day were also going to have planned MOD of 90fsw. 1st was actually 78fsw and 2nd 51 fsw. Other than that I always watch the analysis of my tanks when I pick them up as I don't own an analyzer.

 

[martinskarin]

The few times I dived notrox I analyzed myslef (only did 2 dives on it...) and I am planning to follow that rule for the future. I think I would worry to death and feel more or less panic just because of that and the hole dive would be ruined...! And as someone said, it only take once....

 

[CuNanoTube]

I always analyze my tank and my father's tank before each dive. I built a sweet analyzer set-up in a hard case (I built the analyzer as well) so that I can have it on the boat. I once got a top-up on my pony at an unfamiliar shop and found out that they guy filled it with 36%. If I had had to use it at the 130' planned depth for that dive I would have been in trouble.

 

[DA Aquamaster]

First, I'm not GUE trained and certainly not one of their biggest defenders, but I do respect that they seem to be highly disciplined and self-consistent.

Shamelessly copied from GUE (Web):

Cylinder Marking: The Fine Points
Cylinders should be stripped of all unnecessary stickers (place VIP on bottom), Nitrox banners or other non-essential markings. Numerous markings create dangerous confusion. Each cylinder should be marked horizontally on two sides with large three-inch high numbers identifying its MOD (Maximum Operating Depth). Oxygen cylinders should be marked "20" with the word OXYGEN written horizontally along the tank, preventing divers from mistaking "20" with "70" or "120".
The diver's name should also be marked on the cylinders to simplify identification. Last name should be used to avoid confusion. No gas percentages should be placed on the cylinder for identification purposes, as these require divers to make underwater calculations. Any content information is the result of analysis and should be placed near the neck of the bottle. For example, when analyzed, a 18.2% oxygen and 45% helium mixture would read 18.2/45; when analyzed, a 32% Nitrox mixture would read 32.0%. The date analyzed and tester's initials should be included with the percentage marking.

You alluded to it, but I'll go so far as to say it: IMHO GUE gets a "pass" on tank marking. They do mark tanks (cylinders) but they do it their own way -go figure.

Anyone that would confuse a GUE cylinder marked with a last name, "20", and "OXYGEN" for their own air cylinder really doesn't comprehend the most basic hazards of diving. The bigger issue (from my perspective) is that this brings into question that standards may have been lowered too far. Do we really need to protect OW / AOW divers from this threat? Aren't divers still being trained to be not just sure, but damned sure, of what they are planning to breathe?

I agree the total approach works very well and I am a big believer in marking stage and deco bottles with the MOD.

However, having a MOD of 20', 70' 120', etc on it does not prevent someone from filling it with any gas, so the concept also requires the discipline to not put anything else in the tank, and if you do, to remove the old MOD marking and apply a new appropriate MOD marking. If that is not done, the practice potentially creates a hazard instead.

 

[lowviz]

I agree the total approach works very well and I am a big believer in marking stage and deco bottles with the MOD.

However, having a MOD of 20', 70' 120', etc on it does not prevent someone from filling it with any gas, so the concept also requires the discipline to not put anything else in the tank, and if you do, to remove the old MOD marking and apply a new appropriate MOD marking. If that is not done, the practice potentially creates a hazard instead.

Nothing in your post that I can disagree with, especially the part about preventing someone from filling it with something stupid. Which is why I always analyze. Mix once, check twice.

As far as the potential hazard part, maybe we should start a thread about the hazards of diving with DIR types?

Nevermind, I'm in enough trouble on the board. Best that I pass on the bait and find something constructive to do.

 

[DevonDiver]

... I should think common sense would have anyone picking up a tank to dive should very well make sure that it's "their" tank

Common sense. Diving Accidents.

Two terms that have a unique relationship.

Relying on every diver exhibiting common sense is a recipe for disaster IMHO. That's why a foolproof marking system was introducted.

I've seen vacationing divers, using rental equipment, who've just picked up the nearest assembled kit and started kitting up before a disgruntled fellow customer has spotted them and demanded their kit back. It happens.

However, having a MOD of 20', 70' 120', etc on it does not prevent someone from filling it with any gas, so the concept also requires the discipline to not put anything else in the tank, and if you do, to remove the old MOD marking and apply a new appropriate MOD marking. If that is not done, the practice potentially creates a hazard instead.

How much discipline is needed to prevent any likelihood of a human error? Again, the use of a foolproof marking system further mitigates the risk of human error. Busy dive operations/fill stations can make mistakes. Maybe one in ten thousand tank fills.... but that's all it might take to cause a fatality.

MOD markings are great - if you are a qualified nitrox diver and understand what the abbreviation means and why it is used. But how does it mitigate the risk that an untrained diver can pick up the tank and use it.

All divers are trained what Nitrox means - and that they shouldn't use it unless qualified. They aren't all trained what MOD means and won't necessarily recognise the danger. Hence, the logical benefit of marking nitrox tanks as NITROX, rather than just an MOD.

 

[lowviz]

...//.... All divers are trained what Nitrox means - and that they shouldn't use it unless qualified. They aren't all trained what MOD means and won't necessarily recognise the danger. Hence, the logical benefit of marking nitrox tanks as NITROX, rather than just an MOD.

So we should force (what I consider to be) one of the most highly skilled and disciplined groups of divers to add a "Nitrox" sticker so today's lowered standards pick-your-agency divers won't walk away with it? Maybe there is another way to address this problem?

I'm beginning to think that vacation diving is getting WAY out of control.

 

[DevonDiver]

So we should force (what I consider to be) one of the most highly skilled and disciplined groups of divers to add a "Nitrox" sticker so today's lowered standards pick-your-agency divers won't walk away with it? Maybe there is another way to address this problem?

I'm beginning to think that vacation diving is getting WAY out of control.

Are you saying that GUE divers emerge from the womb with some sort of genetic disposition to understand the words 'Nitrox' and 'MOD'?

GUE educates divers about nitrox as standard. Most agencies don't. That isn't a reflection of diver training - just a difference in approach to the progressive syllabus of diver education.

YOU didn't do your entry-level training with GUE. So there was a point in time where YOU were a diver and YOU didn't have education about nitrox. Did YOU feel that was out of control at that time?

What I am saying is that: one of the most highly skilled and disciplined groups of divers decided to ignore the common industry standard on the basis that their members received specific in-depth education, but failed to consider the implications of co-existing with divers who, as standard, do not receive that education.

Given that that agency extols the virtues of team diving and standardisation; IMHO it seems pretty hypocritical for a minority agency to not recognise the obvious issue of failing to standardise their tank marking protocols in line with the wider diving community.