POLL, Nitrox tank use and analyze

[Chill Diver]

I always do my own analysis. The shop I get my fills at will not let you out the door without filling in their log book with date, analysis, signature, Nitrox certification etc. So far, the only mixes I have requested have been 32% and 21%. Interestingly (for me, anyways) is that, although they use a banked system and should theoretically always have the same mix, I have measured everything from 30 to 34% in the tanks I have picked up. I have never been close enough to NDL or PO2 limits for this to matter to me, but if I had been deep or down a long time and I hadn't checked, I could have been in trouble.

Say what you will about PADI training, they were very clear that you ALWAYS analyze your tanks before using them. I either want to do it, or watch it done in front of me. I can't argue with their position on this.

Final note, the last time I picked up my AL80, I got my very first 32.0% reading on the analyzer! Usually it is off by .1 or .2%.

 

[Rainer]

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.

What are you talking about??? GUE teaches that EVERY cylinder should be analyzed *and* labeled with its contents. If some other diver is ignorant of nitrox, one would still hope he'd (1) not dive someone else's cylinder, and (2) not dive a cylinder with an analysis sticker he doesn't understand staring him in the face. Really, if he's going to ignore all that, he's just as liable to ignore a big, stupid nitrox wrapper...

 

[lowviz]

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.

Well stated.

First, I didn't do entry-level with GUE because I don't like the whole concept of how "fundies" is taught. Nothing more. It is starting to "gel" with me, I make it a point to NOT support what I don't like, so I'm kinda screwed on this one.

Yes, when I was OW I didn't have much of a clue about nitrox. However, I did ask a lot of questions and was unlikely to pick up the wrong gear. OK, I'll give you the point about not leaving deadly cylinders lying around unmarked with a standard nitrox sticker. I just don't think that it is much of an issue. The DIR practitioners that I have come in contact with have all made me feel good about DIR in general. In spite of this, I think that I'm on a different path. I rely on instructors like you to teach me new skillls. I like new ideas that can be tested and adopted or rejected.

PM me if you are ever teaching in the NE USA. I'd really enjoy taking a course from you.

Thanks for the "give and take", hope I didn't offend...

 

[TSandM]

There was a period of time in my diving career where I didn't know about Nitrox, but I did know that my tanks were my tanks, and I shouldn't dive someone else's.

I do not mark my tanks with big banners, except for the ones which got so marked because the shop I was dealing with at the time required it. I DO mark all my tanks with analysis stickers . . . including the air tanks. What's more, all my tanks are marked as my tanks, or Peter's tanks; we don't dive someone else's tanks. I actually picked up someone else's tank at the dive shop the other day, because it was a blue HP100 with a Genesis tilted valve, and I didn't realize ANYBODY else around here had tanks like that. But the tank got analyzed, by ME, and labeled; when I realized I had someone else's tank, I still dove it, because I had analyzed it.

Novice air diver on a big group boat? HE may not know the tank he's grabbed isn't one he should dive, but the owner of the tank should be missing it . . .

 

[miketsp]

..snip..

Novice air diver on a big group boat? HE may not know the tank he's grabbed isn't one he should dive, but the owner of the tank should be missing it . . .

Not necessarily. Not all dive boats have the 2 cylinders for the 2 dives racked side by side.
This happened to me. There were 3 of us diving EAN out of a group of 12 divers. We loaded 8 cylinders (2 each plus 2 spares) all with BIG green and yellow stickers and carefully put them all together into one corner of the boat to isolate them from the rest of the plain grey cylinders and also to facilitate a final measurement of the mix.
After everyone had set up I happened to notice that there were only 4 marked cylinders left over and I went to look for the missing one. When I found it I questioned the owner of the rig and he had no idea that he'd grabbed a Nitrox cylinder or even what the difference was!
But I only spotted this in time because we were a minority, I knew who had ordered EAN and we'd grouped the cylinders. Otherwise we would have only picked this up for the second dive.

 

[ThomasScherrer]

OMG.. so the conclution is ??
if there is nitrox on the boat, some tanks for some divers,
all divers on the boat should be nitrox certified in nitrox,
no matter what they ordered or bring for that day,
OR ?
the nitrox users should go arround and double check ALL tanks for all divers
so miss placed tanks are found in good time.
what can we do ?
to make it as safe as possible, AND as smart and easy at the same time.

 

[Rhone Man]

I'll admit to having dived with a tank of nitrox without having analysed it. Not often (twice I think), but certainly done it. There had been a SNAFU, and the only working analyser was left in the other shop, and we were going to have to wait 90 minutes to go diving if we wanted them to fetch it, etc. Two things affected my decision to say "screw it". Firstly, I knew the shop used a membrane system, and (a) all their nitrox came out at 29.5-30.5%, and (b) it could not possibly be richer than 40%. Second, I knew our dive wouldn't go deeper than 70 feet.

BUT

On the other hand, what I have always found very interesting is that divers are fanatical about checking their mixes in any cylinder labelled "nitrox". But scarcely anyone ever checks their mix in a tank supposed to be filled with air, even if it has been filled off a membrane system...

 

[RTee]

As TS&M, not all my tanks are adorned by the full gammit of sticker paraphanelia stated in the PADI EAN diver textbook. As a minimum, they will either carry an O clean VIP sticker (if O clean) and an analysis label with the appropriate info or for those that are not O cleaned a standard VIP sticker, a PREMIX ONLY sticker (to prevent inadventent partial blending) plus the analysis label.

Stage bottles...my 40 cft 100 O2 stage bottle carries the standard markings for such content. Wrt my 80 cft, it carries an O clean VIP, and analysis label and homemade MOD stickers based on the mix I am carrying for that specific dive to supplement my 100 O2 (if carried).

EAN Analysis for recreational diving...my GF is normally my buddy. She has 100% faith in me when it comes to analyzing the mix and it is reciprocal. Normally we go together for our fills but there are times when only one will be going with some or all our single tanks. Notwithstanding, we always follow the same routine...monitor the filling, check the pressure and analyze the content, label the tanks and fill the register (mandatory at our LDS). LDS has one to two analyzers on site.

Doubles/stage bottles. That is in my ball park as for one she would have a hard time handling a set of 2 X 117 cft but I also need to ensure (through gas analysis) that I have the proper mixes that I require for the dive(s) I have in mind (backgas, primay and secondary deco mix) as my diving profile and planned deco schedule (and contingency deco schedule) are based on those mixes.

If I go on dive trips outside my local areas, I may either use my own tanks (if travelling by car) or be forced to use rentals if my tanks and facilities do not match (partial blending vs non O clean tanks or vice versa) or if I am travelling by plane. Notwithstanding, every tank gets analyzed and marked before me and or GF dive with them.

The only exception for the marking that I can think of was on my last trip to Cozumel...All Nitrox tanks had the top portion painted green (or green and yellow)and carried standard fill of 32 EAN. The dive operator carried one or two analyzers on board. Once our backplate was put on a specific tank, we would analyze our mix (varried from 31 to 33) and then enter the data immediately in our dive computers. We would repeat the process for the second (and third or fourth dive if applicable).

Importance of analysis...several folks have already covered the subject. Based on a personal experience, I requested two fills of 32 % at a diving shop (partial blending) away from home to support back to back deep dives on wrecks. After analysis, we ended up with two mixes that were slightly higher...one being close to 35% and the other 37%. Needless to say (I hope so) we adjusted our dive profile accordingly and concentrated our dives on the top portion of those wrecks.

 

[DevonDiver]

If some other diver is ignorant of nitrox, one would still hope he'd (1) not dive someone else's cylinder, and (2) not dive a cylinder with an analysis sticker he doesn't understand staring him in the face. Really, if he's going to ignore all that, he's just as liable to ignore a big, stupid nitrox wrapper...

You prevent dive accidents with "hope"?

I prefer to mitigate risks with more concrete solutions.

 

[AfterDark]

"Nothing is foolproof to a suffciently talented fool". Of which I fear there are far too many of with c-cards these days. Sometimes the only thing left is hope! I've never had someone take one of my tanks but I'm pretty sure the J valve(s) would confuse them enough to stop.