Have you ever been filled with Nitrox when you wanted Air?

[raftingtigger]

The usual mistake of filling a regular tank with nitrox comes generally from places that bank EANx. It is actually more common than you would think to get this kind of mistake in such a setup. Having the wrong valves turned in the filling station, give you EANx in your non stickered tank.

This is the crux of my question. So it does happen. Banked EANx accidentally filled into my air tanks wouldn't cause ME a problem - but that's because of how deep I dive (or don't dive). For someone else who dives deeper it might be.

 

[bergersau]

The Yellow & Green tank wrap sticker is a big visual warning to air only divers that the tank MAY not contain air and that they shouldn't dive that particular tank.
It is NOT a substitute for the nitrox qualified diver who plans to use that tank doing his/her own analysis and marking the tank with a temporary contents label with their signature, the date the mix and the fill pressure noted.

 

[Dr. Lecter]

The odds are rather low, but it almost certainly has happened. The way it's most likely to happen, however, makes the risk of harm rather small.

Could an air diver be the unlucky recipient of a deadly mix when their tank gets mixed up with the deco tank I dropped off for a partial pressure blend of 80-90%? Yes, though their tank probably wouldn't be O2 clean and therefore wouldn't get filled, and even if it did the blender should (though hasn't always) stuck some kind of analysis on it that might warn them...but anything is possible. If they dove it, they'd probably tox shortly after passing 30'--if they didn't incinerate themselves before they even got in the water.

But a rich banked mix of 36%--which is the only real worst-case inadvertent EAN fill you could get--only gives you a pO2 of 1.78 at 130'. Is it beyond the 1.4/1.6 limit currently taught? Yes. Is it a pO2 that's basically right around where plently of people have and continue to dive air (with PSAI even offering a tech course on air down to 240')? Yes.

So, it's probably not going to happen, and even if it does happen the worst that's going to occur on a recreational dive is that you hit 1.7 and change in your pO2...which might very rarely kill you, but in general won't. And if you're diving air below 130', you should probably be making sure it's actually air. I check all my fills for CO, and any fill I'll be taking on a deco dive for O2%, including air.

 

[bamafan]

A few years ago I went cave diving at Villa Derosa in Akumal Mexico. Most of the dives are in the 40 to 60 feet deep range in the Tulum area so getting a free nitrox fill is not an issue. We were planning on doing the Blue Abyss on the last day and I intended to go down to about 200'. I checked my doubles and they analyzed at 26 percent. It actually took a while to find a set that just had air. At this time they did not have an analyzer and were using an off-site fill station who just topped up the tanks with air. Apparently the only time they drained them was when someone ordered nitrox. Other than this they are a good operation and I feel that it is the divers responsibility to check their tanks so I didn't see a problem other than if you go take an analyzer.

 

[AfterDark]

It has been my belief for a while that Nitrox should be included in OW. OW divers aren't trained to analyze tanks so they don't know for sure what is in their tanks - basically a "trust me" dive on whoever filled their tanks. The agencies want the money for the specialty, though, so I don't see anything changing.

Trained to analyze tanks. Trained? How long does it take show someone how to analyze a tank for O2 content? I think 5 min for normal people, maybe 10 for a monkey. Theroy, and physic should be taught at the OW level so that people will understand WTF is going on.

 

[Superlyte27]

What's this "air" you speak of? Is that the stuff you used to put into tires?

 

[Crass3000]

Aren't stickers bad to put on tanks? Especially bad to put on steel tanks? While it's not worth losing your life over a sticker, they aren't good for tanks and promote rust as does paint on tanks once it chips.

 

[BluewaterSail]

The fact that nitrox costs more does not keep a mistake from being made. I remember the story of the guy who got 100% helium in his tanks. What a deal! Lucky for him, even though the dummy didn't measure the gas in his tanks, he did decide it was worth his time to do an equipment check before jumping off the boat. He was very fortunate to pass out while taking some test breaths off his regulators...

I carry my own O2 meter with me even when I travel, and I always check my tanks on the day of the dive. I don't care what someone else tells me is in the tank, or is on a label, I want to see it for myself.

 

[Gren]

I agree that if nitrox isn't part of OW, analyzing tanks should be. I think we should analyze every tank because mistakes do happen. I hope that we eventually get combo O2/CO analyzers and every tank is checked for both.

Sent from my Nexus 7 using Tapatalk HD

---------- Post added July 11th, 2013 at 07:27 AM ----------

Another thought, while it may not be common it could definitely happen.

I rent a tank from shop A, use it, refill it at shop B with 50/50, use 1000 psi on deco, return in to shop A and they top it off. It's now a 40% blend and the shop/next customer has no idea.

 

[Peter69_56]

I check all my fills for CO, and any fill I'll be taking on a deco dive for O2%, including air.

We were taught on our TDI deco course to analyse ALL cylinders for the dive. Never assume you have air in your bottom gas and say 50% and 32% in your deco tanks. Always, always, always analyse before use.

All my potential Nx cylinders have stickers, Green knobs and MOD tape on them (even if air). All my Nx regs have green hoses on them to indicate O2 clean. All Nx secondary regs have white tape over the top with the MOD on it. I figure if you put up enough fences, you might just keep Murphy at bay for another dive.