O2 cleaning question

[AfterDark]

I've been curious about this for awhile and I'm sure someone can answer this with ease. I'm not Nitrox certified so I'm going by what I know about gas and PP.

I assume the cleaning is required due to the higher % of the O2 in the blend.

So my question is why has this never been an issue when diving with air below 130' where the PP of the O2 is 14.7 psi (1ATM) or greater? Or have we just been lucky all these years?

 

[Spg01]

"I assume the cleaning is required due to the higher % of the O2 in the blend."

It depends on how the shop makes their notrox, there are at least 2 options.

Option 1: Partial pressure blending, which requires an 02 cleaned tank. This is where they put 100% 02 into your tank and then top off with air to get the desired mix.

Option 2: The nitrox is already blended and stored in holding tanks, no 02 cleaning required. Your tank will not see 100% 02 levels, just whatever your mix contains as long as it is less than 40%.

The partial pressure that has to do with depth is different and has nothing to do with being 02 cleaned. It is the partial pressure of a gas at depth. Without going to much into it, a high partial pressure of 02 at depth can kill you and other bad things. That is why there are max operating depths (MOD) that are based on the nitrox mix you are breathing.

The best way to learn more would be to take a class. Or if you google EANx or nitrox there is a lot of information out there. But it is the internet and everybody lies so you should not believe everything you read.

Including this.


As a note, The partial pressure of 02 in air at 130' is 1.04 and it is recommended to keep it below 1.4.

 

[Buoyant1]

It's not so much about the partial pressure, it's the delivery of O2 into the receptacle that requires the need for the cleaning. (i.e. viton O-rings, special lubricants, etc.)

The more O2 in the mix the more chance it has to combust! (i.e. go boom)

If I'm missing anything, I'm sure it will be revealed! (see just above!)

 

[AfterDark]

"I assume the cleaning is required due to the higher % of the O2 in the blend."

It depends on how the shop makes their notrox, there are at least 2 options.

Option 1: Partial pressure blending, which requires an 02 cleaned tank. This is where they put 100% 02 into your tank and then top off with air to get the desired mix.

Option 2: The nitrox is already blended and stored in holding tanks, no 02 cleaning required. Your tank will not see 100% 02 levels, just whatever your mix contains as long as it is less than 40%.

The partial pressure that has to do with depth is different and has nothing to do with being 02 cleaned. It is the partial pressure of a gas at depth. Without going to much into it, a high partial pressure of 02 at depth can kill you and other bad things. That is why there are max operating depths (MOD) that are based on the nitrox mix you are breathing.

The best way to learn more would be to take a class. Or if you google EANx or nitrox there is a lot of information out there. But it is the internet and everybody lies so you should not believe everything you read.

Including this.


As a note, The partial pressure of 02 in air at 130' is 1.04 and it is recommended to keep it below 1.4.

Thanks that answers my question in total. My starting assumption was wrong.
Thanks for the info. I'm not interested in diving NITROX $30.00 for a fill is way more than I'm willing to spend. Heck $7.00 for air is a lot. A fill was .25 when I started diving! Thanks again.

 

[Spg01]

I hear you on the price of a nitrox fill. I leave nitrox more for vacation diving, multiple dives/multiple days. Here at home I am fine with air diving from the beach.

 

[rigdiver]

Thanks that answers my question in total. My starting assumption was wrong.
Thanks for the info. I'm not interested in diving NITROX $30.00 for a fill is way more than I'm willing to spend. Heck $7.00 for air is a lot. A fill was .25 when I started diving! Thanks again.

And, what was the price of gasoline when an air fill was 25 cents?

 

[LakeCountyDiver]

But isn't a tank only O2 cleaned up intill you fill it? I keep hearing all this O2 cleaning stuff but anything less then 40% I learned it dont matter.

Am I wrong that O2 cleaning only sets it for 100% O2 and then is void if you put anything else in it like 36%?

 

[aquaregia]

A tank is O2 cleaned until you put non-clean gas in it.

For anything less than 100% it doesn't matter, however partial pressure blending puts 100% into your tank and a failure on a continuous blending system will result in your tank seeing 100%. I'd want the tank O2 clean unless I was filling from banks.

 

[fire_diver]

No, O2 cleaning is good until you take it to a dirty shop that puts something other than "oxygen clean" air in it.

Dang it aquaregia, quit posting while I'm typing. LOL

 

[LakeCountyDiver]

Ok just so I get this straight the terms "Oxygen clean air" "non-clean gas" means that you are referring to the 21% air that the compressor pulls? Or the oxygen that is put into the tanks for Nitrox?

The reason I ask this is because this is a heavily debated topic in my area. Some think it is a must and others thing it is a big joke and others this it is a good intill you put anything but 100% O2 in it. Like the Nitrogen dirtys the tank.

I heard it both ways in my Nirtox class so it is hard to say. I have had it said that if they want it O2 cleaned for PP filling then you would have to have it clean every time you wanted it filled otherwise why do it at all.

IDK I dont even dive with NITROX