Will I die IF

[yle]

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.

Just curious... why can't a tank that is not O2 cleaned be filled with banked nitrox? I ask only because you state that here, but I've witnessed plenty of non-O2 clean tanks filled from a 32 bank with zero problems or concerns.

 

[rsingler]

Just curious... why can't a tank that is not O2 cleaned be filled with banked nitrox?

It can. It happens all the time, as long as it's stickered for Nitrox. As for how clean it has to be to get stickered for banked Nitrox compared with compressed air, I'll let the guys who do it for a living comment, as I only know what I was taught in my VIS course.

Perhaps my reply wasn't clear.

 

[yle]

It can. It happens all the time, as long as it's stickered for Nitrox. As for how clean it has to be to get stickered for banked Nitrox compared with compressed air, I'll let the guys who do it for a living comment, as I only know what I was taught in my VIS course.

Perhaps my reply wasn't clear.

Hmmm... weird. I've seen unstickered (I mean no nitrox stickers) tanks get filled with nitrox from banks or membrane systems regularly. The shop I get my nitrox from has a membrane system they can set to anything up to 36. They advertise that they'll fill any tank, nitox stickers or not, doesn't have to be O2 clean. The membrane filters nitrogen out of the air until the concentration is the desired mix, puts it in the tank.

When I teach the nitrox class, I've added my own section of "here's what the book says are the rules, and here is what you will see actually happening... and here's why it's not a problem." I figure it's important for students to know all three of these.

 

[rsingler]

Hmmm... weird. I've seen unstickered (I mean no nitrox stickers) tanks get filled with nitrox from banks or membrane systems regularly. The shop I get my nitrox from has a membrane system they can set to anything up to 36. They advertise that they'll fill any tank, nitox stickers or not, doesn't have to be O2 clean. The membrane filters nitrogen out of the air until the concentration is the desired mix, puts it in the tank.

When I teach the nitrox class, I've added my own section of "here's what the book says are the rules, and here is what you will see actually happening... and here's why it's not a problem." I figure it's important for students to know all three of these.

Yep. I can understand that. I don't think there's a significant safety issue with banked Nitrox, no matter what the regulations say. Your example proves that others feel the same way. That's why I suggested, "check with the guys that do it for a living."
Partial pressure blending is a real concern, where cleanliness matters. Banked Nitrox? Probably not so much...

 

[scubadiver888]

Yep. I can understand that. I don't think there's a significant safety issue with banked Nitrox, no matter what the regulations say. Your example proves that others feel the same way. That's why I suggested, "check with the guys that do it for a living."
Partial pressure blending is a real concern, where cleanliness matters. Banked Nitrox? Probably not so much...

Yep, this is why the guy I worked with (and experienced a flash fire) switched to a system that mixed the O2 and air then puts it in the tank. Far less worry if the valve and tank are O2 clean. Over a decade since he did partial pressure blending and no worries about the tanks or valves being O2 clean. Heck, even when he services my Nitrox tanks, he doesn't O2 clean them.

 

[Barnaby'sDad]

Hmmm... weird. I've seen unstickered (I mean no nitrox stickers) tanks get filled with nitrox from banks or membrane systems regularly. The shop I get my nitrox from has a membrane system they can set to anything up to 36. They advertise that they'll fill any tank, nitox stickers or not, doesn't have to be O2 clean. The membrane filters nitrogen out of the air until the concentration is the desired mix, puts it in the tank.

When I teach the nitrox class, I've added my own section of "here's what the book says are the rules, and here is what you will see actually happening... and here's why it's not a problem." I figure it's important for students to know all three of these.

The requirement for a Nitrox sticker to get a banked fill varies from shop to shop. Most places I’ve hit in Virginia, they want to see a Nitrox sticker on the tank. Down in Florida (I hit a few places)...they didn’t seem to care too much.

I bought a used/recently cleaned tank from a shop in Fort Lauderdale and the guy looked at me like I had two heads when I asked for a Nitrox sticker to be put on the tank. When I explained why...he just kind of laughed and rolled with it.

 

[formernuke]

As others have stated the issue if you add above 40% O2 to the tank to blend down. If they are blending with below 40 the risk of flash fire is much lower.

I just won't get fills from shops that dont use the "clean air" and I ask for it everytime making sure they know my tanks are O2 clean even if I'm only getting 21 percent.

 

[Eric Sedletzky]

Nitrox stickers were something that was popular back when nitrox first took off as a recreational gas. It might have been a left over or adaptation from tech diving? Who knows.
I still see a few around, but nowdays
banked nitrox is popular enough either produced through a membrane system or made in a nitrox stick before it goes into compressor. PP blending is considered kind or archaic now and home brew compared to the pre mixed varieties available commercially. I don’t know of any shops in my area that will do PP fills, too much trust based on very little, fanatical cleaning, and liability.
On the Socal dive boats that offer nitrox, they all have a membrane system and 32 flows out of the tap. No stickers needed, you just put a green tag on your tank when you need a fill and the nitrox whip comes out. You’re expected to know your MOD and they have an analyzer for you to use to verify it if you don’t have you own.
Any shop in my area that banks nitrox will fill any tank that’s in hydro and Current VIP just like air, no stickers needed. A PP fill? Even if it had a sticker who’s to say someone didn’t just slap it it on a regular air tank and tell them it’s O2 clean when it’s not. If I owned a shop and got into PP fills (which I wouldn’t) I wouldn’t put 100% O2 into anything unless I cleaned it...at a pretty good price too. We used to do all that crap back when I was into that scene. No thanks.

 

[Ghost95]

A little off topic but what actually happens if there is an O2 fire in a tank being filled? Does the tank rupture? Does the fire burn up the O2 leaving a hypoxic mix?

I've heard that there can be an O2 fire in a tank and you not realize it. From what I understand, the oxygen dosen't burn but rather supports the combustion of the petro chemicals in the tank. So do small oil deposits burn but without enough gas expansion to be noticed.

Just curious as to what happens.

 

[happy-diver]

so as it is no one stores petro or any other chemicals or lumps of grease or other junk
even in their non O2 cleaned tanks
so there's just nothing happens as an O2 fire in a tank being filled just doesn't happen