NITROX marked tanks MUST be filled to 24% or greater?

[NAM001]

Myths and untrue...

Welders grade is vacuumed out and then filled from the SAME exact source. The only difference is serialized tracking......thats it.....

I got that right from (2) different large O2 suppliers. They were honest....they told me point blank that the slight upcharge was for them to have lot/serial numbers on there......but that every tank they fill from the source is treated the same exact way.

Medical Grade...doesnt necessarily require a prescription....but Medical Oxygen treatment does - particularly if you want insurance to cover it. Some suppliers now have "Divers Grade"...which is their medical O2...with a different color tank and tracking mechanism.

There are more specs to O2. welding i think requires 99.4% pure. medical 80% pure with a vac then fill, aviation same as medical only low dewpoint. The bulk tank meets all the min requirements as it is like 99.99 pure. 99.9% does not allow for much moisture probably -200 degree f dew point. That leaves the only operational difference is the tracking and fill methods and cost.

 

[NAM001]

Good info I will have to check with my suppler if both are vacuumed out and filled I might shift to welders. Things could have changed since I started mixing my own 30 years ago. At first it was hard to get 02 if you told them it was for diving.

I thnk it is medicaL not welding that is vacuumed prior to fill..

 

[Peter69_56]

I thnk it is medicaL not welding that is vacuumed prior to fill..

Medical cylinder is vacuumed of all gas, Only then it is filled, In this way they can certify the gas for medical use.
The welding cylinder is refilled from the same gas but not evacuated of gas prior, so theoretically could contain some other gases like acetylene or LPG etc.

 

[NAM001]

Medical cylinder is vacuumed of all gas, Only then it is filled, In this way they can certify the gas for medical use.
The welding cylinder is refilled from the same gas but not evacuated of gas prior, so theoretically could contain some other gases like acetylene or LPG etc.

That is exactly what i have always understood. If you ingest you vac. If you burn you dont.

 

[Peter69_56]

I actually think if you have a vacuum "thus you have no gas" and you drown??????? Not sure if a primary reg will let vacuum through to your lungs and cause them to boil?

 

[Storker]

Last i knew any mixd above 23.5 and 50 psi required a O2 cleaning and also a Nitrox Sticker on the tank.

I guess this is regional, because around here O2 cleaning is only required for PP blending if your mix doesn't exceed 40%. Continuous blending up to 40% doesn't require O2 cleaning here, and so far I haven't been arrested for only having a piece of tape with the mix, MOD, fill date and initials on my nitrox filled tanks.

 

[NAM001]

I guess this is regional, because around here O2 cleaning is only required for PP blending if your mix doesn't exceed 40%. Continuous blending up to 40% doesn't require O2 cleaning here, and so far I haven't been arrested for only having a piece of tape with the mix, MOD, fill date and initials on my nitrox filled tanks.

I agree with you 100% I am a PSI inspector ane that is the stated policy. Their defence for it is that PP blending of 23.5% would require it iuf done from an empty tank. . There was a lot more to it but that is where that came from. Personally i follow the 40% rule/guidline what ever, but i dont fill for anyone but my self. However you cant get around it if you are PP blending. You are going to excede 40% when you PP. I believe that the PSI folks are probably correct. Their mission is to not just prevent all accidents but to provide processes that wil assure that you will not be found at fault in a legal action. 23.5 >50 psi provides for that. Its a case of protection run amuk

I operate on the premis that > 40% is O2 cleaning. OCA is needed to keep that cleaning valid. The sticker is for tanks with >40% in them to signify that only OCA must be used in the tank. 32% can have grade E put in it and still be used for nitrox no band required. Im sure that there is a lot of disagreement with it but that is what i go by, right or wrong. The NITROX band was to identify the tank is used for O2 use based on NASA's testing saying >60% acts like 100% < 60 acts like air. Scuba adopted the 40% line to allign with noa 1 adn 2 with some fudge to cover error. deco 50 and 100 are pretty standardly accepted to be O2 clean tanks.

 

[NAM001]

I actually think if you have a vacuum "thus you have no gas" and you drown??????? Not sure if a primary reg will let vacuum through to your lungs and cause them to boil?

I meant that if you breath the gas you vacuum that tank prior to refilling it with O2 to insure no contaminates is in the tank.

 

[Peter69_56]

I agree with you 100% I am a PSI inspector ane that is the stated policy. Their defence for it is that PP blending of 23.5% would require it iuf done from an empty tank. . There was a lot more to it but that is where that came from. Personally i follow the 40% rule/guidline what ever, but i dont fill for anyone but my self. However you cant get around it if you are PP blending. You are going to excede 40% when you PP. I believe that the PSI folks are probably correct. Their mission is to not just prevent all accidents but to provide processes that wil assure that you will not be found at fault in a legal action. 23.5 >50 psi provides for that. Its a case of protection run amuk

And on that note, I Partial Pressure fill all my tanks.

I Oxygen clean all my tanks regardless of the intended gas. Given I can do it for near nothing its not a huge expense, same with all cylinder valves, all done for 100% oxygen. Given I do all my fills I know the air quality so I can run any level of O2, air, trimix and not worry about contamination. It may be over the top but it does mean I can use any gas in any tank without fear.

I also clean and fill other friends tanks but depending on who has done the clean and where they have been filled. I have cleaned some supposed tanks that have been oxygen clean and CLEARLY this was not done even thought they were charged for the service.

My tanks are all marked with "Oxygen Clean Service" and if they have other than air, will have duck tape on the neck stating Nx X (level of oxygen) and MOD X (Max Operating Depth) if a NX blend up to pure O2. If Trimix then same O2 X (level of oxygen), He X (level of helium), MOD X______XX showing minimum to maximum operating depth.

 

[Peter69_56]

I meant that if you breath the gas you vacuum that tank prior to refilling it with O2 to insure no contaminates is in the tank.

I know what you meant, silly time had kicked in and I couldn't help myself, sorry. My empty brain from my last post ran away with my fingers.