Should Nitrox tanks have the percentage clearly listed?

[ktb]

I've only received Nitrox fills at 2 locations (1 local and 1 out-of-country on vacation), so I'm not sure of the SOP for this.

At my local location, I'm REQUIRED to analyze my tank and enter the appropriate information in the Nitrox log, but I'm also EXPECTED (required?) to write the percentage and MOD on a taped label. I think we did the same thing on vacation, but I was new to Nitrox at the time and with folks from my local shop so I just followed their lead.

Due to an unfortunate event today, I happened to take special note that someone had a green and yellow Nitrox sticker on their tank, but nowhere was a percentage listed on the outside. I don't think it was a contributing factor to anything, but it was a question asked that I couldn't answer.

Is having the percentage listed on the outside just good practice or is it required and perhaps this person removed it before diving . . . ?

[Joshua Smith]

It would be bad not to mark the tank, IMO. I use different nitrox mixes all the time, as a CCR diver. There should *at the very least* be a piece of tape at the top of the bottle, with the mix % written down on it. Even though I nearly always carry ~40% in my two eanx bailout bottles, I would make a point of re-analyzing one if it somehow lost the marking tape.

I've only received Nitrox fills at 2 locations (1 local and 1 out-of-country on vacation), so I'm not sure of the SOP for this.

At my local location, I'm REQUIRED to analyze my tank and enter the appropriate information in the Nitrox log, but I'm also EXPECTED (required?) to write the percentage and MOD on a taped label. I think we did the same thing on vacation, but I was new to Nitrox at the time and with folks from my local shop so I just followed their lead.

Due to an unfortunate event today, I happened to take special note that someone had a green and yellow Nitrox sticker on their tank, but nowhere was a percentage listed on the outside. I don't think it was a contributing factor to anything, but it was a question asked that I couldn't answer.

Is having the percentage listed on the outside just good practice or is it required and perhaps this person removed it before diving . . . ?

[Tom Nic]

SOP to have tape or something affixed to the tank that at least lists the percentage, and typically the MOD at 1.4

We remove the tape after the tank has been used before it's refilled, mainly as a simple convenience for us identify used tanks.

[Dusty2]

I was taut that it is required that you put a sticker on your tank at the time you analyze it and log it. There are two reasons for this. First so that when you set up at the dive site you will know what % your tank holds and what the MOD is for that mix at 1.4 (the official safe levels) and can plan accordingly. The second is so that anyone who dives with you is aware of these limits. This is also critical if you have an event like today so that the emergency first responders know that you were diving nitrox and what percentage so they know that oxygen toxicity could be a factor.

You should never dive a nitrox tank that does not have the O2 percentage clearly marked on it unless you personally analyze it before you dive.

[Penopolypants]

If they are diving nitrox then yes, absolutely, they should mark it. Keep in mind that they may have been diving air in a nitrox-ready tank. Theoretically they should mark that too, I guess, but I can't say I've ever seen it or done it myself.

[Dusty2]

Another thing I learned recently or should I say had hammered into my brain. If you are diving with someone using nitrox and you are not or you are at a lower % this needs to be part of your buddy briefing. The one on the lower % must know the MOD for the highest % diver and the one on the lowest % should determine the no deco time for the dive.

[Dashrynn]

I have dove with some divers that have a perm 50% or 40% and some even 75% taped on there deco bottles in some kind of reflective tape. If you wonder why I was diving with a diver who has deco bottle, it was for practice reasons.

Also I know that most people have the max operation depth (mod) and % mixture on the nitrox bottles (deco or not) written in ink (or something) on a sticker thing (in some removable ink or something).

[Grateful Diver]

That would be a big YES ... your nitrox cylinder should be clearly labeled with the analyzed nitrox percentage.

Best management practice is to mark both the EAN percentage and the maximum operating depth on a piece of tape on the shoulder of the cylinder, where it's easy to see. Don't ever assume that just because you asked for a certain mix that's what you got. Don't assume that the big-ass banner on the tank tells you anything about the contents of the tank ... all that tells you is that the tank has been prepared to receive nitrox (and not all nitrox tanks will have one of those anyway).

Another good thing to do is, as soon as you analyze, write the readout ... to the nearest tenth of a percent (e.g. EAN32.2) on the cylinder. Adopting that method gives you a way of KNOWING that you've analyzed the cylinder, because some shops will affix a piece of tape indicating the REQUESTED mix (e.g. EAN32) ... which isn't necessarily what you ended up with. Labeling to the tenth of a percent tells you at a glance that you are reading the analyzed contents, rather than the requested contents.

Someone mentioned deco bottles ... it's even MORE important to analyze and mark those, since you're gonna be breathing them at a high PPO2 level for an extended period of time.

... Bob (Grateful Diver)

[spatman]

Another good thing to do is, as soon as you analyze, write the readout ... to the nearest tenth of a percent (e.g. EAN32.2) on the cylinder. Adopting that method gives you a way of KNOWING that you've analyzed the cylinder, because some shops will affix a piece of tape indicating the REQUESTED mix (e.g. EAN32) ... which isn't necessarily what you ended up with. Labeling to the tenth of a percent tells you at a glance that you are reading the analyzed contents, rather than the requested contents.

ditto what bob said above. if the tape on my tank doesn't have my handwriting on it, then i'll analyze if before i breathe it. and generally, no tape means it's spent and needs a refill.

[LCF]

Yes, Nitrox tanks should have a marking indicating the analyzed contents of the tank. As Bob says, using three significant figures can help identify an analyzed tank from requested percentage. It really is critical to analyze the contents of your tank, because even the best people make mistakes at dive shops.

Tanks which are permanently marked with an MOD are generally deco bottles or stages which will contain the same mix all the time - but those tanks STILL require a current analysis sticker before they should be dived.

We don't remove the analysis tapes from our tanks before we take them to the dive shop, but we take them off and put them back on in a vertical orientation on the tank. That way, we know the tank has been used, and the shop knows what the prior analysis was, which helps them plan the next fill.

[boydski]

We don't remove the analysis tapes from our tanks before we take them to the dive shop, but we take them off and put them back on in a vertical orientation on the tank. That way, we know the tank has been used, and the shop knows what the prior analysis was, which helps them plan the next fill.

Hi Lynne,

I always remove the old analysis tape from any bottles while I am filling them (especially deco gas) and then put the old tape across the valve face (so that I know the tank is full). This helps me keep the full/empty cylinders apart and tells me at a glance that a cylinder is full, but has not been analyzed yet (i.e. there's no contents tape on the neck, but tape across the valve face indicating it is full). Having the old tape on the cylinder prior to filling does help significantly when mixing!

Its been a long time since I've shown up to a dive site with a nearly empty tank, so I'm guessing the tape is helping with my Sometimers...

[Marc]

I am not a fan of Nitrox stickers on tanks. There have been a lot of times that I have dived with someone that has a sticker, but is diving air.

Mix, MOD, ppo2 and date.

[CaptnJack]

Rather than reusing analysis tape to indicate full vs. used I just label full tanks "full"
Everything gets analyzed and labeled like "31.4%" with tape on the neck before it goes in my truck to go diving.

This is also critical if you have an event like today so that the emergency first responders know that you were diving nitrox and what percentage so they know that oxygen toxicity could be a factor.

I'm not sure what you think they would do differently? Most O2 toxicity events (there hasn't been one locally in eons knock on wood) end up as drownings anyway and that's ultimately the cause of death. Stop the dorwning and they'll recover from the tox.

[ktb]

I am not a fan of Nitrox stickers on tanks. There have been a lot of times that I have dived with someone that has a sticker, but is diving air.

I'm thinking (hoping) that was the case here, as I didn't see any percentage indicator on his tank. But this is exactly why I've been reluctant to put the nitrox stickers I received on my tanks. If I do, and I get an air fill, I guess I will still use a tape label and mark it for 21% so even I don't forget!

Again, I don't think it had any bearing on the incident, but it made me think.

[LCF]

If I do, and I get an air fill, I guess I will still use a tape label and mark it for 21% so even I don't forget!

If you are getting your tanks filled at a place that fills Nitrox or mix, it is a good idea to analyze even air fills. You never know when someone will grab the wrong tank, or misunderstand the instructions. Many of us get Nitrox in tanks that don't wear the big banners, so many shops won't bat an eye at putting Nitrox into an "unbannered" tank.

[Tom Nic]

Many of us get Nitrox in tanks that don't wear the big banners,

Question - I have noticed this. Is there a simple answer to "Why" this is? Is it not wanting to deteriorate the tank?

Not trying to start anything, just curious, and I've noticed this (no big nitrox stickers) more among divers with a, shall we say, certain mindset. Is this a technical diver thing? A certain school of thought? Or just simply a personal preference for a certain "look"?

OK, I guess that was more than just one question.... Apologies in advance to the OP for any potential hi-jack - wouldn't ask this except I think that the answers have been pretty clear and uniform to the original question.

[defied]

Many of us get Nitrox in tanks that don't wear the big banners,

Question - I have noticed this. Is there a simple answer to "Why" this is? Is it not wanting to deteriorate the tank?

Not trying to start anything, just curious, and I've noticed this (no big nitrox stickers) more among divers with a, shall we say, certain mindset. Is this a technical diver thing? A certain school of thought? Or just simply a personal preference for a certain "look"?

OK, I guess that was more than just one question.... Apologies in advance to the OP for any potential hi-jack - wouldn't ask this except I think that the answers have been pretty clear and uniform to the original question.

Personal preference. 0]

D(B)

[Sounder]

Many of us get Nitrox in tanks that don't wear the big banners,

Question - I have noticed this. Is there a simple answer to "Why" this is? Is it not wanting to deteriorate the tank?

Not trying to start anything, just curious, and I've noticed this (no big nitrox stickers) more among divers with a, shall we say, certain mindset. Is this a technical diver thing? A certain school of thought? Or just simply a personal preference for a certain "look"?

OK, I guess that was more than just one question.... Apologies in advance to the OP for any potential hi-jack - wouldn't ask this except I think that the answers have been pretty clear and uniform to the original question.

Chicks dig bald tanks.

My 130s have 32% in them 99% of the time, but if I'm doing a Rec-triox dive, it may not have nitrox... it may have trimix 25/25. They may also have air in them, or they may have 18/45 or 15/55 when they're being used as temporary storage for filling shenanagins (this is pretty common actually). As such, when I dive them there is usually 32% in them, but I want to be sure. There may be a trace of helium in them too left over from storage uses... and I like knowing that too.

So for me, I like the "VooDoo Gas" stickers... if you look closely, they're NOT "nitrox" stickers. They read "this tank MAY contain mixes other than air." In other words, analyze the damn tank and don't trust a sticker on the outside, you dummy. This goes along with the way I (dummy) approach my gas - I check it no matter WHAT is on it. Sometimes when I pick them up, they've already got "32%" on them, and usually someone I trust dearly checked and wrote that... but I check again anyway. I mean, why not?! It's something to do while you're standing around BSing anyway. There are certain people I will trust to analyze my tanks for me, but if you think about that - it's a pretty serious "trust," and not something I take lightly (neither do they). Beyond that, I analyze my own before I trust it.

Even on my trip to the Channel Islands last year, where the whole boat was breathing 32% for the whole trip and the boat was pumping 32% for the whole trip, everyone analyzed their tanks before every dive. It was always 32% +/- 1%, and we weren't pushing 1.4 MODs for the most part, but I know I had 32% for every single dive... because I analyzed to confirm what I already "expected."

[CaptnJack]

Not trying to start anything, just curious, and I've noticed this (no big nitrox stickers) more among divers with a, shall we say, certain mindset. Is this a technical diver thing? A certain school of thought? Or just simply a personal preference for a certain "look"?

Because a big green and yellow nitrox banner tells you nothing about what might actually be in the tank. air, 32%, 36%, 40%, 50%, 80%. The banner doesn't add any information beyond analysis tape which is required anyway.

[Tom Nic]

Chicks dig bald tanks.

Ah. I thought so. (about the responses and the "certain mindset", not about the chicks)

And, for the record, I'm all about the - ANALYZE YOUR OWN TANKS DUMMY! - mindset.

And I think "Voodoo Gas" stickers look cool.

Just wondered, and my wondering has been turned into clarity!

[Peter Guy]

re the "Big Green Banner" -- I, and I suppose most of us, have heard that it is "required by Federal Law" to have such a sticker. Do any of you know what "Federal Law" (I'm supposing a CFR # here) requires such -- or at least purports to require such?

[CaptnJack]

re the "Big Green Banner" -- I, and I suppose most of us, have heard that it is "required by Federal Law" to have such a sticker. Do any of you know what "Federal Law" (I'm supposing a CFR # here) requires such -- or at least purports to require such?

That is totally bogus, there's no law requiring nitrox banners. In fact the word nitrox isn't even mentioned in the DOT packaging specifications although oxidizers and mixed gases are discussed.

The green and yellow banner is a bastardization of the CGA guidelines for color coding, green = oxygen, yellow = breathing air. But even those color coding guidelines (and matching dedicated valves, CGA 540 for oxygen, CGA 346 or 347 for air) are not law either.

[Grateful Diver]

re the "Big Green Banner" -- I, and I suppose most of us, have heard that it is "required by Federal Law" to have such a sticker. Do any of you know what "Federal Law" (I'm supposing a CFR # here) requires such -- or at least purports to require such?

That is the fantasy of a certain dive shop owner ... there is no "federal law" mandating how a nitrox cylinder gets labelled ...

... Bob (Grateful Diver)

[camerone]

Not trying to start anything, just curious, and I've noticed this (no big nitrox stickers) more among divers with a, shall we say, certain mindset. Is this a technical diver thing? A certain school of thought? Or just simply a personal preference for a certain "look"?

Not only do they tell you nothing about what's in the tank, they're a PITA to remove for inspection purposes. If you're doing the inspection right, you have to look for pitting all over the tank. Since the stickers get nicked, water collects underneath them, doesn't dry out, and then that's usually where most of the pitting happens. Large stickers are a surefire way to hasten the demise of your tanks...

I have a few Voodoo as stickers, one of which I use on my Dil bottle, but it's small. I just put it there to annoy people

Otherwise, I try to go with the bare minimum - a VIP sticker and a MOD sticker set (190, Oxygen, Argon "do not breathe") That's it.

[ArcticDiver]

For you who dive both Air and EAN in both Bannered and Plain Cylinders:

The shop/boat fills both Air and Nitrox. You have asked for Air. If you only analyze Nitrox cylingers how do you know you got Air and not Nitrox in some percentage?