O2 purity?

hirudin · 25th May 2005, 01:15

Hi!

While investigating purchasing my own bank of O2, I have encountered a few people who use industrial grade welder's oxygen for their 02 cylinders instead of aviation/medical grade. They claim sufficient purity for diving combined with a significant cost saving.

What is the general consensus on this application... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble?

-Jesse-

**wedivebc** · 25th May 2005, 01:23

Quote: (Originally Posted by hirudin)

Hi!

While investigating purchasing my own bank of O2, I have encountered a few people who use industrial grade welder's oxygen for their 02 cylinders instead of aviation/medical grade. They claim sufficient purity for diving combined with a significant cost saving.

What is the general consensus on this application... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble?

-Jesse-

The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches.
Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way.

**rdriver** · 25th May 2005, 01:59

Quote: (Originally Posted by wedivebc)

The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches.
Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way.

Being An Aircraft Wrench and Inspector I second this, none the less I have been using welding O2 for CCR diving for the past year with no ill effects........ although my wife might disagree with me

**wedivebc** · 25th May 2005, 02:31

Quote: (Originally Posted by rdriver)

Being An Aircraft Wrench and Inspector I second this, none the less I have been using welding O2 for CCR diving for the past year with no ill effects........ although my wife might disagree with me

Yeah I know what you mean. In my case it's a tough call where senility ends and ill effects begin

Skipbreather · 25th May 2005, 03:36

This one's been beat to death on other boards, but hey- it is a new one to you I'd bet. At any rate, there is a SMALL (miniscule?) chance that welding O2 will cause you grief. Are you willing to take it? The choice is yours.

You then ask "how miniscule?" The answer is "Who the heck knows for sure?" My very unprofessional guess is that it is very much dependant on the QC used at your local gas supplier when they process returned cylinders. I blended nitrox in the old days w/ welding O2 wif noe illlll effffects (Urp…).

My local gas supplier will gladly sell me medical grade O2 (“We donn need no stinkin’ O2 perscripshon!”). Never the less, a couple of years ago I switched to aviator’s grade.

Reasons:
1. Lower dewpoint = less chance of 1st stage icing in the 5 deg C water I often dive.
2. No, um, “arrangements” needed.
3. Costs just a tad less.
4. Biggest reason- comes supplied at 2400 to 2500 psi vs 2100 psi for the med grade.

So what to do? I’d personally spring for aviator’s grade even if it added 50% to the cost of an O2 fill for my bank bottles. An extra $1 per dive- when viewed in perspective to all the other involved Rebreather dive costs- is worth it to me to eliminate the O2 as a cause when I’m asking myself at 50m “dude, why do I feel so totally funky?”

That being said, if the ONLY O2 I could lay my fill whips on for whatever reason was welding grade, I’d use it without all that much worry. I’d compensate w/ perhaps just a bit more bailout gas being carried and be ready to go to it w/ somewhat less provocation.

Hope this helps you make your own very personal decision.

Ken

***Beanie*** · 25th May 2005, 08:04

Quote: (Originally Posted by wedivebc)

There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches.

yeah OK

big Bang when they fill the cylinder with O2 at source

here industrial is 1/3 the price of diving

Duncan Price · 25th May 2005, 11:44

Quote: (Originally Posted by hirudin)

... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble?

I use welding grade but that is not an endorsement. As a chemist I find it difficult to believe this business about acetylene contamination. IMNSHO there's more danger about other stuff in your loop.

USSMEG · 25th May 2005, 12:56

Quote: (Originally Posted by wedivebc)

The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches.
Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way.

I inquired about the possibility of contaminants in the past also. With my of them using ISO 9000 for all the process's, I was told all Cylinders are evacuated before filling. This way they prevent any problems with explosions. I have used welding O/2 for many years and every once in a while even check it to be sure its 100% and its always been.

Paul

hirudin · 25th May 2005, 23:34

Thankyou all for sharing your experience. I have seen the topic broached on other boards, but typically regarding OC. So I guess my curiosity is in part due to the nature of the gas mixes in CCR.

Thanks again,

-Jesse-

**wedivebc** · 26th May 2005, 00:28

Quote: (Originally Posted by Beanie)

yeah OK

big Bang when they fill the cylinder with O2 at source

here industrial is 1/3 the price of diving

Actually it may not go bang in low concentrations. In air the lower explosive limit is 2.5% Can't seem to find the lowest % in O2 but I am sure it is greater than zero
http://www.answers.com/topic/explosive-limit?hl=lel

25th May 2005, 01:15	#1 (permalink)
hirudin New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: May 2005 Location: rock-hopper Posts: 52	O2 purity? Hi! While investigating purchasing my own bank of O2, I have encountered a few people who use industrial grade welder's oxygen for their 02 cylinders instead of aviation/medical grade. They claim sufficient purity for diving combined with a significant cost saving. What is the general consensus on this application... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble? -Jesse-
(Offline)

25th May 2005, 01:23	#2 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,444	Quote: (Originally Posted by hirudin) Hi! While investigating purchasing my own bank of O2, I have encountered a few people who use industrial grade welder's oxygen for their 02 cylinders instead of aviation/medical grade. They claim sufficient purity for diving combined with a significant cost saving. What is the general consensus on this application... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble? -Jesse- The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches. Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

25th May 2005, 01:59	#3 (permalink)
rdriver Supporting Member Current Rebreather/s: Megalodon Other Rebreather/s: Sport Kiss Classic Kiss Join Date: May 2005 Location: Monroe, WI 53566 U.S. Posts: 147	Quote: (Originally Posted by wedivebc) The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches. Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way. Being An Aircraft Wrench and Inspector I second this, none the less I have been using welding O2 for CCR diving for the past year with no ill effects........ although my wife might disagree with me
(Offline)

25th May 2005, 02:31	#4 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,444	Quote: (Originally Posted by rdriver) Being An Aircraft Wrench and Inspector I second this, none the less I have been using welding O2 for CCR diving for the past year with no ill effects........ although my wife might disagree with me Yeah I know what you mean. In my case it's a tough call where senility ends and ill effects begin __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

25th May 2005, 03:36	#5 (permalink)
Skipbreather Reads the fine print Current Rebreather/s: Megalodon Home Build Other Rebreather/s: Not Bought Yet MK 15.X Home Build Join Date: Mar 2005 Location: Chicago, Illinois, USA Posts: 557	This one's been beat to death on other boards, but hey- it is a new one to you I'd bet. At any rate, there is a SMALL (miniscule?) chance that welding O2 will cause you grief. Are you willing to take it? The choice is yours. You then ask "how miniscule?" The answer is "Who the heck knows for sure?" My very unprofessional guess is that it is very much dependant on the QC used at your local gas supplier when they process returned cylinders. I blended nitrox in the old days w/ welding O2 wif noe illlll effffects (Urp…). My local gas supplier will gladly sell me medical grade O2 (“We donn need no stinkin’ O2 perscripshon!”). Never the less, a couple of years ago I switched to aviator’s grade. Reasons: 1. Lower dewpoint = less chance of 1st stage icing in the 5 deg C water I often dive. 2. No, um, “arrangements” needed. 3. Costs just a tad less. 4. Biggest reason- comes supplied at 2400 to 2500 psi vs 2100 psi for the med grade. So what to do? I’d personally spring for aviator’s grade even if it added 50% to the cost of an O2 fill for my bank bottles. An extra $1 per dive- when viewed in perspective to all the other involved Rebreather dive costs- is worth it to me to eliminate the O2 as a cause when I’m asking myself at 50m “dude, why do I feel so totally funky?” That being said, if the ONLY O2 I could lay my fill whips on for whatever reason was welding grade, I’d use it without all that much worry. I’d compensate w/ perhaps just a bit more bailout gas being carried and be ready to go to it w/ somewhat less provocation. Hope this helps you make your own very personal decision. Ken
(Offline)

25th May 2005, 08:04	#6 (permalink)
*Beanie* give a man an inch....... Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,172	Quote: (Originally Posted by wedivebc) There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches. yeah OK big Bang when they fill the cylinder with O2 at source here industrial is 1/3 the price of diving __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
(Offline)

25th May 2005, 11:44	#7 (permalink)
Duncan Price Sump Monster Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Feb 2005 Location: Wells, Somerset, UK Posts: 335	Quote: (Originally Posted by hirudin) ... is industrial grade oxygen used for welding OK for diving, or is that inviting trouble? I use welding grade but that is not an endorsement. As a chemist I find it difficult to believe this business about acetylene contamination. IMNSHO there's more danger about other stuff in your loop.
(Offline)

25th May 2005, 12:56	#8 (permalink)
USSMEG USSMEG Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Mar 2005 Location: Mass Posts: 293	Quote: (Originally Posted by wedivebc) The purity of welding oxygen is actually higher than medical grade (USP) by the standards however, according to my Praxair distributor the gas all comes from the same tank and all cylinders are handled the same at the plant. What changes is how the cylinders are handled by the end user. There exists a possibility that small quantities of acetylene can be found in O2 cylinders if the user had run the O2 down and did not have flash-back arrestors on the torches. Now the chances are probably quite remote but since the consequence of error is quite high I wouldn't take the chance. Remember with a rebreather contaminents are not just breathed they are rebreathed over and over again so a little poison goes a long way. I inquired about the possibility of contaminants in the past also. With my of them using ISO 9000 for all the process's, I was told all Cylinders are evacuated before filling. This way they prevent any problems with explosions. I have used welding O/2 for many years and every once in a while even check it to be sure its 100% and its always been. Paul
(Offline)

25th May 2005, 23:34	#9 (permalink)
hirudin New Member Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: May 2005 Location: rock-hopper Posts: 52	Thankyou all for sharing your experience. I have seen the topic broached on other boards, but typically regarding OC. So I guess my curiosity is in part due to the nature of the gas mixes in CCR. Thanks again, -Jesse-
(Offline)

26th May 2005, 00:28	#10 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,444	Quote: (Originally Posted by Beanie) yeah OK big Bang when they fill the cylinder with O2 at source here industrial is 1/3 the price of diving Actually it may not go bang in low concentrations. In air the lower explosive limit is 2.5% Can't seem to find the lowest % in O2 but I am sure it is greater than zero http://www.answers.com/topic/explosive-limit?hl=lel __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
(Online)

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