Air in tank marked Nitrox?

[WaterDawg]

Otherwise I would have thought a accident could easily ensue if the tanks were mixed up and another diver was expecting Nitrox but received air.

I think the opposite is MORE dangerous; A diver expecting air and diving EAN!

 

[ScubaSixString]

This does happen rather frequently but should pose no problems as long as the tank is marked with the oxygen percentage I.E. EAN21 in this case.

If I am doing a shallow dive (ie under 10 metres) I wont bother mixing nitrox and will fill my tank with air (Through a filter of course so it stays O2 clean) to save time and to free up the fill station

It happens frequently?

So analyzing your mix before you use it DOES serve a purpose

 

[RonFrank]

A friend came back from diving today and in his photos I noticed he was wearing a yellow and green tank marked "NITROX". Now he isn't Nitrox certified but he said the dive op had assured him they had just filled the tank with air. This seems a bit odd to me. If a tank is marked for one gas, I would have expected people to stick to that gas (in this context at least). Otherwise I would have thought a accident could easily ensue if the tanks were mixed up and another diver was expecting Nitrox but received air.

Is this kind of situation common practise with dive operators?

But I can think of nothing really wrong with it. I'd agree with the poster who suggest that an analysis of the tank to ensure it's at 21% O2 is a good idea. As long as it's o2 clean 21% mix, what is the difference?

Interesting, I did a three tank Nitrox dive in Jupiter, and my Nitrox tank was NOT marked with the Nitrox sticker. However it did have an O2 clean label, and sure enough when I analyized it, it came up at 36% O2 which is what they said was the mix.

I just bought two tanks, and they are both O2 cleaned. Unfortunately I really don't want two Nitrox tanks. I can have one filled with an O2 clean mix of 21% but I think they change me for a Nitrox fill in that case. I also plan on taking them to the Hole, where I know there is NOT O2 clean air available. So I'll have to waste on O2 clean on one.. ohhh well...

 

[Charlie99]

A friend came back from diving today and in his photos I noticed he was wearing a yellow and green tank marked "NITROX". Now he isn't Nitrox certified but he said the dive op had assured him they had just filled the tank with air.

Is this kind of situation common practise with dive operators?

Not uncommon for privately owned tanks, since the diver knows how to verify that the nitrox was actually bled out before filling with air.

OTOH, air in nitrox marked tanks is NOT common with dive operators and dive shops. The main danger is that, even if the tank was just topped off with air, unless they bled off the nitrox beforehand, then it will have an elevated level of oxygen.

I would have no hesitation in diving the tank, but only if I had an anlyzer available to measure the O2 fraction in the tank beforehand, just as if I expected nitrox to be there.

I bet the dive operator does a lot of "trust me" dives (as in "trust me, you'll be fine on this dive if you just follow the divemaster"). In the situation where this really was the only tank available, the proper course of action by the dive op / boat crew would be to reanalyze the tank in the presence of your friend, explaining what they were doing, and showing him that it was indeed air in there.

 

[Charlie99]

Not sure if it's common ....But I can think of nothing really wrong with it. ...

To me it's a potential indicator of a problem with the attitude and safety of the dive operator. They were essentially saying to TikTok's friend, "trust us, it's really air".

While not a big deal in itself, this sort of thing often is a leading indicator of other problems that aren't as visible.

 

[StSomewhere]

Maybe air divers should only used tanks marked "Compressed Air".

IMO every tank is suspect until I've analyzed it. Think the logic through. You are relying on the absense of a sticker on a tank to assume its OK to dive with. :06:

 

[Azza]

Maybe air divers should only used tanks marked "Compressed Air".

IMO every tank is suspect until I've analyzed it. Think the logic through. You are relying on the absense of a sticker on a tank to assume its OK to dive with. :06:

Good points about analyzing the tank first. I never bother because I fill my own tanks so I know if it is air or not.

If someone gave me a tank with a nitrox sticker on it and told me it was air I would analyze it first, or empty it and get it refilled with air. Of course I would watch the refilling to make sure it was only air...

 

[Gary D.]

Maybe air divers should only used tanks marked "Compressed Air".

IMO every tank is suspect until I've analyzed it. Think the logic through. You are relying on the absense of a sticker on a tank to assume its OK to dive with. :06:

See, there is a plus to filling at the Fire station. 21% is all they can pump.

Gary D.

 

[mrobinson]

If someone gave me a tank with a nitrox sticker on it and told me it was air I would analyze it first, or empty it and get it refilled with air. Of course I would watch the refilling to make sure it was only air...

The more I learn about diving, the more I realize that knowing how to analize tanks should be a basic skill everyone should be taught... rant over.

Nitrox stickers are for people who need everyone to see them.

Edit - If everyone knew how to analize, then the stickers would be usless.

 

[String]

A friend came back from diving today and in his photos I noticed he was wearing a yellow and green tank marked "NITROX". Now he isn't Nitrox certified but he said the dive op had assured him they had just filled the tank with air. This seems a bit odd to me. If a tank is marked for one gas, I would have expected people to stick to that gas (in this context at least). Otherwise I would have thought a accident could easily ensue if the tanks were mixed up and another diver was expecting Nitrox but received air.

Is this kind of situation common practise with dive operators?

Cant see the problem, nitrox stickers just mean the tank is O2 cleaned for nitrox. Lots of new tanks come ready cleaned and with stickers. Theres no problem putting (double filtered) air in them at all.

Just because you CAN put nitrox in a tank doesnt mean you have to.

To get a nitrox fill, here anyway you have to show evidence of qualification, analyse it and sign a fill log to that effect.