Oxygen compatible air

[Warren_L]

Does anyone know if there is a CSA standard for analyzing oxygen compatible air? I've got a couple of oxygen clean tanks which I would like to use with regular air. Shops that fill nitrox should be fine, but I've heard from some non-nitrox shops say that their air is O2 compatible, but I don't know how to verify or check for this??

 

[Welsh_Dive_Pro]

I've never actually hear the phrase "O2 Compatible Air" before.
However, here in the UK, you can get your cylinders (whether 02 clean or not) filled from any compressor.
Now the problem arises when filling a clean cylinder from a compressor pumping air that isn't double filterered. If the compressor is only single filtered then the air isn't guaranteed free from hydrocarbons, therefore the cylinder would have to be cleaned again afterwards if you wanted to use EAN (the compressor operator would remove the EAN / o2 clean sticker from your cylinder). The way around this is to always use a compressor that is double filtered (if they pump Nitrox through it then it should be, ask though to be sure) or to purchase your own personal filter which can then be used to double filter the compressor.

I hope this makes sense, and answers your query.

p.s. I hope this isn't teaching you to suck eggs.

 

[AzAtty]

At p. 41:

O2 Compatible Air
Oxygen 22-23%
Carbon monoxide, 2ppm
Carbon dioxide, 500ppm
Gaseous hydrocarbons, 25ppm
Oil mist particles, .1mg/cubic meter

CGA Grade "E" air (tire filler stuff we breathe)
Oxygen, 19-23%
Carbon monoxide, 10ppm
Carbon dioxide, 500ppm
Gaseous hydrocarbons, not significant
Oil mist particles, 5mg/cubic meter

Some shops fill with better-than-Grade "E" air, but you'd have to look up the CGA standards to find out which grade is close to the O2 compatible spec. You can buy the spec in electronic format from the CGA on this page for $33.00.

 

[sharkmasterbc]

Modified grade E Air (which is O2 compatable) is what it's called in Canada (correct me if I'm wrong). I belive the shop has to send in samples and if the sample is free enough of hydrocarbons and moisture then it is rated to be O2 compatable. If your cylinder is filled with non O2 compatable air then you will need to have it O2 cleaned before filling again with trox.

 

[d33ps1x]

Good to know.

I would love to keep my tanks O2 clean but not a lot of nitrox around here.

No idea why a shop wouldn't want their air "more" clean and at least keep to the standard even if they don't sell the oxygen. I can always buy that myself.

 

[Warren_L]

Thanks for the information guys - this is very useful. I'll do a bit more researching on this for my own edification.

Modified grade E Air (which is O2 compatable) is what it's called in Canada (correct me if I'm wrong). I belive the shop has to send in samples and if the sample is free enough of hydrocarbons and moisture then it is rated to be O2 compatable. If your cylinder is filled with non O2 compatable air then you will need to have it O2 cleaned before filling again with trox.

That is precisely the reason why I am looking into this.

 

[chrpai]

From GUE Tech manual
At p. 41:

O2 Compatible Air
Oxygen 22-23%
Carbon monoxide, 2ppm
Carbon dioxide, 500ppm
Gaseous hydrocarbons, 25ppm
Oil mist particles, .1mg/cubic meter

Since when does Air have 22-23% O2? Its completly stupid to mention the O2 content in Air spec. They should be mentioning Dew point instead.

ANDI defines it as:

ANDI O2 COMPATIBLE AIR
Carbon Monoxide <2ppm
Carbon Dioxide <500ppm
Dew point -50<
Gaseous Hydrocarbons <25ppm
Condensed Hydrocarbons <.1ppm
Particulate Matter <2 microns

 

[AzAtty]

...I'm just quoting the book, right or wrong though it may be. Consider this table for not one, not two, but FIVE different specifications (including US Navy, ANDI, and IANTD) for O2 compatible air, all of which specify O2 content, and one of which leaves dew point to "per client". Incidentally, the ANDI spec calls out particle size, but does not call out allowable particle concentration.

Clearly, there is more than one way that people are skinning the O2 compatible cat.

 

[mwilding]

Around here, they call it "high-filtered" air

 

[chrpai]

...I'm just quoting the book, right or wrong though it may be. Consider this table for not one, not two, but FIVE different specifications (including US Navy, ANDI, and IANTD) for O2 compatible air, all of which specify O2 content, and one of which leaves dew point to "per client". Incidentally, the ANDI spec calls out particle size, but does not call out allowable particle concentration.

Clearly, there is more than one way that people are skinning the O2 compatible cat.

Every one of them says 20-22% which is the commonly accepted standard by the CGA. The 22%-23% strikes me as so strange because it doesn't include the lower boundry of 20%.