Nitrox Tank Marking

[RainPilot]

Interesting...I was left with the impression that the nitrox stickers (bands) were required.

No scuba police. What is required is whatever the place that does your fills requires.

I thought the same. Does everyone reanalyze to confirm the blend percentage on rentals?

Always. Never trust your life to what some random person has written on a piece of tape.
I wouldn't let my tech instructor analyse a tank for me even though he probably does it better than I ever could.

If I'm going to die from a brain fart, it will be MY brain fart.

 

[Jeremy Williams]

Interesting...I was left with the impression that the nitrox stickers (bands) were required.

I put bands on my tanks. There may not be a ‘SCUBA police’ that requires anything in particular but bands may be required at any given dive shop. A shop can (and will) decline to fill your tanks with nitrox if you don’t meet their requirements... and you can’t call the SCUBA police to make them do it.

In the US there are three regulatory regimes that come into play immediately. Insurance, DOT, and OSHA all have the ability to inspect and either recommend or require changes to the business practices of a dive shop. Insurers are the most far reaching as they are typically looking at cumulative liability for the entire operation. But a recommendation from any of them carries a lot of weight.

As far as I can tell there is absolutely no requirements for DIVING a tank of nitrox or filling it yourself. All the requirements are around the BUSINESS of filling the tank.

 

[boulderjohn]

At VIP time they have to come off for corrosion check, it's annoying.

It certainly is. When I took my first PSI/PCS tank inspection course, they emphasized taking off all such markers. In my latest update, there was no mention of it. I think they realized what a PITA it was, and what little purpose it served.

In my case, all my tanks are O2 clean and the VIP sticker is marked accordingly.

Same here. All my tanks get O2 cleaned annually, and the VIP sticker indicates that. It is the only markinig I have.

Interesting...I was left with the impression that the nitrox stickers (bands) were required.

It is a common misunderstanding.

Here's my theory, in multiple parts.

1. Nitrox used to be considered so dangerous that the annual Dive Equipment and Manufacturing Association (DEMA) did not allow any mention of it at its annual show, and most agencies did not allow it to be taught in their programs. When it was finally recognized as safe enough for recreational use, training requirements and equipment requirements were significant. That attitude has changed a lot, but some of the thinking from the old days still survives to varying degrees. One of those beliefs is t that once you decide to put nitrox in a tank, that is all it should ever be used for, so making a permanent marking made sense.
2. A key part of the previous point that is still taught in most nitrox courses is the ridiculous notion that once a tank has been properly cleaned for nitrox service, it cannot be used for air diving, because putting air in it will contaminate it and make it unacceptable for nitrox. The theory is that when mixing nitrox through partial pressure blending, pure O2 is introduced into the cylinder first, and it will introduce contaminants. Any contamination is dangerous in an O2 atmosphere. Therefore, putting that big sticker on it will prevent you from making that deadly mistake. Well, in partial pressure blending, after you put that O2 in, you top it off with air. If the air you are adding to the tank while making Nitrox is clean enough for that purpose, then that same air should be clean enough to use all by itself.
3. Back when agencies first started to allow Nitrox, technical diving was a brand new concept, and most of those agencies had nothing to do with it. The idea that a tank that holds nitrox can also be used to hold trimix or pure oxygen probably did not occur to them. I think that problem persists throughout the recreational diving community today.

 

[boulderjohn]

I will give an example of when a good-sized indication (like a Nitrox band) can be helpful.

If a dive shop has a lot of tanks and has some of them dedicated to nitrox service, it can make it much easier to tell them apart. For the typical individual diver, it is a different story. Since all my cylinders are O2 clean, I don't need that.

 

[hhmoore]

The reason I thought it was a requirement was 2 different local shops said I had to have the sticker for nitrox fills. I use air probably 3/4 of the time...but, as a result of the above, my tanks sport the big stickers.
As was said - if the shop says I have to have them, I have to have them

 

[scubadiver888]

I thought the same. Does everyone reanalyze to confirm the blend percentage on rentals?

I get my tanks filled. I analyze them at the shop. I take them home. I re-analyze them with my own equipment at home. I label them when some painter tape.

If I used rental tanks I'd do the same thing.

 

[scubadiver888]

The reason I thought it was a requirement was 2 different local shops said I had to have the sticker for nitrox fills. I use air probably 3/4 of the time...but, as a result of the above, my tanks sport the big stickers.
As was said - if the shop says I have to have them, I have to have them

This is a classic example of why the big Nitrox stickers aren't a guarantee of anything. I buy or rent a tank from a shop. I want Nitrox. If I'm buying a tank they insist on a Nitrox sticker. If I'm renting a tank, it already has a Nitrox sticker. I go diving in a river 4 hours from my home on Saturday. The nice local shop offers to refill my tanks for Sunday but they only do air. So I refill my Nitrox tanks with air. Technically, I should invalidate the O2 clean on the VIP and remove the Nitrox sticker. That Nitrox sticker cost me $3 and O2 cleaning the tank and valve costs me $60. Do I get it O2 cleaned for $60? Do I even peel the Nitrox sticker off?

The shop I worked for stopped doing partial pressure blending because people would get the tank O2 cleaned during VIP but then proceed to fill it with air occasionally. They wouldn't tell the shop. One day there is a flash fire because they are filling a contaminated tank with 100% oxygen. They just didn't know it because the customer didn't tell them. But it had the Nitrox sticker.

Any shop which thinks having a Nitrox sticker guarantees the tank is 02 clean is just fooling themselves.

 

[tbone1004]

@scubadiver888 how do you know that air fill invalidates the o2 cleaning?

 

[boulderjohn]

@scubadiver888 how do you know that air fill invalidates the o2 cleaning?

Probably because Nitrox courses say they do.

As I said in my post, though, if the shop's air does not create contamination when it enters a tank during partial pressure blending, why will it create contamination when it enters a tank during an air fill?

 

[JohnnyC]

The ONLY thing that goes on my tanks is the VIP/O2 clean sticker, and a piece of tape with the analysis on it. The only exceptions are tanks that are filled with standard gases, in which case they get two MOD stickers. If a dive shop doesn't want to give me a fill because it doesn't have a nitrox sticker on it, I'll take it elsewhere if they're unwilling to compromise.