Air fills in Nitrox Marked Tanks

[rhwestfall]

 

[Jim Lapenta]

NItrox tanks need to be oxygen cleaned as O2 is flammable it's not just about filling the tanks and going, the tanks have to be certified to hold the enriched air, your lds should be telling you this in addition to giving you a hard time over fills.

Only if filled using partial pressure blending. They do not need to be O2 clean if getting banked gas under 40% or from a membrane or continuous blending system. With these 3 the cylinder never sees 100%.
And they don't need those big ugly wraps. All they need is a sticker saying they were O2 cleaned. Which, by the way, is only valid for the fill at the time of the cleaning/inspection. Once the tank has been used, the next time it's refilled, unless you are 100% certain of the gas coming from the compressor and sure it has the proper filtration, it's a crap shoot as to whether it's still O2 clean.
Some shops may not have the necessary filtration. They may need new filters. They might have a bad cylinder on the compressor and it's no longer pumping O2 compatible gas.
The shop should in no way be giving him a hard time about putting air in his nitrox wrapped tanks. That is just nitpicking BS. He's not using nitrox. He can just take the damn bumper stickers off. And if he decides to use it later, he can find out how they are providing the mix. If it's PP blending, then he'll need to clean the tanks. If it's not PP blending, they can just fill them. He should also try to find a new shop that actually knows what they are talking about and not giving him a line of garbage.

 

[Jim Lapenta]

Ok, another dumb question:

Say I've got a HP100 with ~2,000 PSI of EAN32 in it... am I wrong to just ask a shop to top it off with air? I understand the resulting mix would fall a bit below 28% (of course I'd analyze/verify and mark it on the contents tag), which is fine with me. I don't need nitrox on my next couple dives, my closest dive shop doesn't do nitrox fills... just wondering if I'll look like a big dummy with this request. I don't need 28%, I'd be fine with standard air.

Or am I just best off draining the tank and asking for an air fill? Does it really matter?

Top it off, analyze, and go. Absolutely no need to drain the tank. None, unless you think you have bad gas to begin with.
If they top it off to 3442 (which they should since it's a HP tank) MultiDeco says you'll end up with a 27.4 % mix. I always mix for a max PPo2 of 1.3 for cold water and because of my own risk factors. So the MOD on that would be 126 ft.

 

[tursiops]

O2 is flammable

O2 is flammable

O2 is NOT flammable, at any percentage. Yes, it supports combustion, but it itself does not burn.

 

[grf88]

O2 is NOT flammable, at any percentage. Yes, it supports combustion, but it itself does not burn.

So if it is not flammable does that mean it is inflammable.

 

[Divin'Papaw]

O2 is NOT flammable, at any percentage. Yes, it supports combustion, but it itself does not burn.

Valid point. Thank you for the correction! Many materials will combust in the presence of pure O2 that would never burn otherwise. I do remember my Advanced Nitrox course materials ... sometimes.

 

[Wookie]

NItrox tanks need to be oxygen cleaned as O2 is flammable it's not just about filling the tanks and going, the tanks have to be certified to hold the enriched air, your lds should be telling you this in addition to giving you a hard time over fills.

Before you spout misinformation on a board where there are sure to be experts, you might want to look around a bit and maybe educate yourself a little. Almost nothing you said is correct. But I’m sure it’s what your LDS told you.

 

[Wookie]

LOL

I guess we’re going there ‘again’!

O2 is flammable, low O2 Nitrox (<40%) is not.

No, Jim.

O2 is not flammable. Not in any concentration.

Edit: Damn, beaten like a rented mule hanging off a screen door in a Kansas trailer park during a tornado.

 

[tursiops]

So if it is not flammable does that mean it is inflammable.

No.
https://www.google.com/url?sa=t&sou...kQFnoECEcQBQ&usg=AOvVaw3tqVeh810LKizlu3Vg7-Ym

 

[grf88]

No.
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.theguardian.com/notesandqueries/query/0,,-78567,00.html&ved=2ahUKEwjeicyfw6PiAhUBTBUIHWpIDYcQFjAWegQIEBAI&usg=AOvVaw3ZG4M7gwkcT7T4fp1ZdpOD&ved=2ahUKEwjk-oCqmO3yAhVAFVkFHb3RDJkQFnoECEcQBQ&usg=AOvVaw3tqVeh810LKizlu3Vg7-Ym

I put the smiley there for a reason.