Will I die IF

[NAUI Wowie]

Ok so now I have my own tanks for california diving, 2 steel HP120s they are a couple years old. I always currently fill my tanks with 32% and my pony with air.

Will I DIE if in the future I fill my steel nitrox tanks with air sometime and then fill with 32% after that without swabbing down the insides with baby wipes? Or , could the scuba shop blow up if they did it? Some of that is a bit tongue in cheek but I'm assuming that a scuba shop actually would not fill a tank that has nitrox stickers with air even if I asked, is this correct?

Im just having one of those curiosity days so thought Id post this question.

 

[ofg-1]

Yes, you will die in the future.

 

[Imla]

No problem filling air from a compressor with a proper filter. I would assume any shop who does partial pressure blending would supply only properly filtered air.

 

[jgttrey]

You won't die, but the person filling your cylinders might if they are partial pressure blending and you filled with air that was not filtered to the higher standard. They are relying on you to honor the sticker by not contaminating the cylinder. Is it automatic or even likely, no. But, it's not a made up thing. Keeping O2 stuff clean really is important, not just a scuba boogeyman.

Now, as a practical matter, if the only thing you're ever going to use other than air is BANKED nitrox <40%, then it isn't likely to be a problem. Just know that your stuff is no longer O2 clean. I still wouldn't do it because (a) it's against the rules and (b) maybe someday you need a fill, they nitrox banks are empty and they do a one-off fill by partial pressure blending.

If you want air, ask the shop if they can fill with hyper filtered air, sometimes labeled EAN21. Your shop may do that for everything.

p.s. This actually comes up. My shop uses only hyperfiltered air, which is great. Sometimes, people rent tanks and get them filled at the quarry's dive shop, which is just plain old air. I also know that when my shop's banks are empty they will do a PP blend until they get around to blending a new batch for the banks.

 

[NAUI Wowie]

You won't die, but the person filling your cylinders might if they are partial pressure blending and you filled with air that was not filtered to the higher standard. They are relying on you to honor the sticker by not contaminating the cylinder. Is it automatic or even likely, no. But, it's not a made up thing. Keeping O2 stuff clean really is important, not just a scuba boogeyman.

Now, as a practical matter, if the only thing you're ever going to use other than air is BANKED nitrox <40%, then it isn't likely to be a problem. Just know that your stuff is no longer O2 clean. I still wouldn't do it because (a) it's against the rules and (b) maybe someday you need a fill, they nitrox banks are empty and they do a one-off fill by partial pressure blending.

If you want air, ask the shop if they can fill with hyper filtered air, sometimes labeled EAN21.

I have no idea what type of nitrox the shop uses actually. Well I do fill at two different shops.

 

[Jonny Wishbone]

My LDS calls it 02 compatible air. with all the blending they do, they don't even bother having standard air to help avoid a mistake at the fill station.

 

[jgttrey]

I have no idea what type of nitrox the shop uses actually. Well I do fill at two different shops.

Partial pressure blending involves adding pure O2 to the cylinder and topping with air to get to the mix you want. Super important that everything has to be O2 clean.

For a standard nitrox mix like 32, many shops have it banked - they have blended into a set of storage cylinders and fill your cylinders from that. The difference is that your cylinder and valve never sees pure oxygen, only 32%.

As others have said, chances are that if they are pumping nitrox, it's likely that all the air is o2 compatible, hyper filtered or EAN21, whatever you want to call it. The problem is when one of the shops where you fill only sells air. The chances that it is O2 compatible are slim because they have no reason to spend the money to filter beyond Grade E.

 

[rsingler]

a tank that has nitrox stickers

This is the key.
Your sticker will specify whether the tank has been O2 cleaned and is safe for partial pressure blending up to 100% O2, or whether it is suitable ONLY for banked blends up to 40%.

If you refill an O2 clean tank with banked Nitrox, you're likely fine (but ask the shop if their gas is hyperfiltered or O2 clean).
If you refill any tank (O2 clean or not) with "plain old air", it loses its status and should not be used for partial pressure blending (OR banked Nitrox) until recleaned.

Yeah, asking your shop how its 21% is filtered is worth doing. As noted above, properly filtered "EAN21" is just fine in your tank, and will not even change the status of an "O2 clean" tank.

 

[scubadiver888]

As others have pointed out, if a shop fills your tanks using partial pressure blending then there is a moment they are putting 100% oxygen in the tank. If the tank and values aren't O2 clean, there is a chance of a flash fire (I worked for a guy who experienced this). Once the tank is filled, you are fine. So the only person really in any danger is the guy filling your tanks.

But if they fill a bank of tanks with 32% then fill your tank from the bank then there should be no problems. This is why you don't need O2 clean regulators if you are using less than 40%.

What I didn't see anyone answer was if a fill station would fill your tanks with air if they had Nitrox stickers on them. The short answer is, yes they would.

I've been in locations where there was no dive shop to fill my tanks. There was a guy who serviced SCBA (fire department) tanks. The air didn't have to be hyper clean because it wasn't being used for scuba diving. But they'd fill my scuba tanks. The guy filling my tanks didn't know about Nitrox or enriched air, so a Nitrox sticker meant nothing to him. I remember one time I was getting my high pressures steels filled to 3442 PSI then he went to fill my buddy's AL80 to 3442 PSI because he didn't know any better. I even heard guys would bring the old 6351 aluminum tanks to him and he'd fill them without a proper eddy current test sticker. Heck, he'd fill tanks with no visual inspection sticker.

I'm sure there are also plenty of shops which only fill air and are happy to make a few bucks filling your Nitrox only tanks with air rather than tell you they cannot fill your tanks. It is the other guys problem if I fill your tanks with air. Or like the guy at the fire department, if I fill with air only, the shop owner might have taught me to check the visual inspection sticker was up to date but nothing about filling Nitrox tanks.

Bottom line, no one should fill a tank with a Nitrox sticker with anything less than grade E air (or EAN21 or O2 clean air) but my real life experience has been different.

 

[NAM001]

If they give you any guff tell them to give you a 21 or 22% fil. Then tell them you will accept a top off with HYP E air and call it good. Any intelligent shop will do it. The HYP E air is the key to the issue for shops.