Oxygen Compatible Air Standards (Wallet Card)

PacketSniffer · 10th January 2007, 12:21

Since I travel a lot for my diving destinations, I am usually not familiar with the dive shop where I get fills/tanks. Although, I like to get recommendations from others that have gone before me, sometimes it is not possible. So, to cover myself, I made up this wallet card to keep with me. I can use it to ask the shop if we can compare the ANDI standards that I have to their gas analysis from the compressor. Out of this request to the dive shop, it should become clear what you are getting in your tanks one way or another.

I thought some of my fellow divers might see this as handy so I'm posting it. If you print the 2 pages in duplex, you will get the safe fill rate for oxygen on the back of the wallet card. Print it out on Avery 8371 or it's equivelant business card template. Enjoy!

***EBT*** · 10th January 2007, 12:26

Cautionary note; All the analysis proves is the gas composition at the time of testing.

Personally I look to see the presence of a second filter stack (oil lubed compressors) and a log of the filter changes (which reveals a LOT more about an operations attitude).

***jradomski*** · 10th January 2007, 12:31

Quote: (Originally Posted by EBT)

Cautionary note; All the analysis proves is the gas composition at the time of testing.

Personally I look to see the presence of a second filter stack (oil lubed compressors) and a log of the filter changes (which reveals a LOT more about an operations attitude).

I like to see that the gas tests were performed PRIOR to filtermedia change and on a regular basis.. This shows that the shop is on top of their changes and maintainence.. Even the worse gas systems can usually pass right after changing the media..

GKAM · 10th January 2007, 19:44

I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100?

I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no?

***jradomski*** · 10th January 2007, 20:02

Quote: (Originally Posted by GKAM)

I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100?

I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no?

It depends on the cylinder size.. filling 17l twins at 200 psi per minute is alot of flow (470lpm), filling a single 2l tank at 200psi per minute is not that much (less than 30 lpm )..

470lpm would be greater than the capacity f the 2l cylinder at 200bar!

PacketSniffer · 10th January 2007, 20:31

Quote: (Originally Posted by GKAM)

I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100?

I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no?

It is on the high end of the safe limit. That's why I put "NEVER exceed". It's always better to go slower.

**vidodivr** · 10th January 2007, 21:36

Thanks for contributing to the community.
Have some green

Gilles · 10th January 2007, 23:18

Quote: (Originally Posted by jradomski)

It depends on the cylinder size.. filling 17l twins at 200 psi per minute is alot of flow, filling a single 2l tank at 200psi per minute is not that much (less than 30 lpm )..

I might be wrong, so please correct. Its been awhile since my fill training. This is interesting as I continue to struggle acquiring cleaning solvents for tanks/valves that are due.

I gather risks associated with flow-rate are associated with rapid deceleration of molecules within the whip (discontinuities). Hence reason to keep to a safe rate, which implies very low at start when destination pressure is very low, and higher as destination P gets higher. An issue more relevent with filling of larger bottles.

With smaller bottles, adiabatic heating happens so much easier. Given the small volume, practical to just keep a very low rate all the time. If I feel the bottle getting warm, then I make the assumption that it's too much, and I needle it down some more. I'm normally in the 6-7 bar/min camp, but my bottles are more dangerous.

abowie · 11th January 2007, 02:31

Quote: (Originally Posted by GKAM)

I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100?

I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no?

4 bar (under 60psi) per minute, especially with iddle biddy Rebreather tanks.

***jradomski*** · 11th January 2007, 04:54

Quote: (Originally Posted by abowie)

4 bar (under 60psi) per minute, especially with iddle biddy Rebreather tanks.

I am actually much more concerned filling big cylinders rapidly, since the high flow rate can give particles significant force.. I'm really not concerned about the cylinder heating (its a huge heatsink), I am more worried about heating at the valve and especially particle impingement..

I don't have a problem if someone is filling very small cylinders even 400psi per minute since there is very little gas flow, but since they are small it doesnt take long to fill them so why not go slow.... but big cylinders even 100psi per minute is high..

10th January 2007, 12:26	#2 (permalink)
*EBT* Apprentice Luddite Current Rebreather/s: Classic Kiss Other Rebreather/s: Inspiration Classic Join Date: Feb 2005 Location: UK, Brighton Posts: 1,825	Re: Oxygen Compatible Air Standards (Wallet Card) Cautionary note; All the analysis proves is the gas composition at the time of testing. Personally I look to see the presence of a second filter stack (oil lubed compressors) and a log of the filter changes (which reveals a LOT more about an operations attitude). __________________ Eagles May Soar, but weasels don't get sucked into jet engines! Rebreather World Terms of service Real diving t-shirts for real divers
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10th January 2007, 12:31	#3 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,795	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by EBT) Cautionary note; All the analysis proves is the gas composition at the time of testing. Personally I look to see the presence of a second filter stack (oil lubed compressors) and a log of the filter changes (which reveals a LOT more about an operations attitude). I like to see that the gas tests were performed PRIOR to filtermedia change and on a regular basis.. This shows that the shop is on top of their changes and maintainence.. Even the worse gas systems can usually pass right after changing the media.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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10th January 2007, 19:44	#4 (permalink)
GKAM digital nomad Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: May 2005 Location: Greece Posts: 246	Re: Oxygen Compatible Air Standards (Wallet Card) I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100? I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no? __________________ Stay #
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10th January 2007, 20:02	#5 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,795	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by GKAM) I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100? I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no? It depends on the cylinder size.. filling 17l twins at 200 psi per minute is alot of flow (470lpm), filling a single 2l tank at 200psi per minute is not that much (less than 30 lpm ).. 470lpm would be greater than the capacity f the 2l cylinder at 200bar! __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 11th January 2007 at 04:50.
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10th January 2007, 20:31	#6 (permalink)
PacketSniffer ~~~~~ #417 ~~~~~ Current Rebreather/s: Not Bought Yet Other Rebreather/s: Not Bought Yet Join Date: Jun 2006 Location: Houston Posts: 411	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by GKAM) I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100? I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no? It is on the high end of the safe limit. That's why I put "NEVER exceed". It's always better to go slower. __________________ Far better it is to dare mighty things, to win glorious triumphs, even though checked by failure, than to take rank with those poor spirits who neither enjoy much nor suffer much, because they live in the gray twilight that knows not victory or defeat.
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10th January 2007, 21:36	#7 (permalink)
vidodivr swims in fishes toilets Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Nov 2005 Location: Florida/Michigan Posts: 471	Re: Oxygen Compatible Air Standards (Wallet Card) Thanks for contributing to the community. Have some green __________________ Have a good one, Rob LaLonde CK #087 Narked@90 frame URM
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10th January 2007, 23:18	#8 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 761	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by jradomski) It depends on the cylinder size.. filling 17l twins at 200 psi per minute is alot of flow, filling a single 2l tank at 200psi per minute is not that much (less than 30 lpm ).. I might be wrong, so please correct. Its been awhile since my fill training. This is interesting as I continue to struggle acquiring cleaning solvents for tanks/valves that are due. I gather risks associated with flow-rate are associated with rapid deceleration of molecules within the whip (discontinuities). Hence reason to keep to a safe rate, which implies very low at start when destination pressure is very low, and higher as destination P gets higher. An issue more relevent with filling of larger bottles. With smaller bottles, adiabatic heating happens so much easier. Given the small volume, practical to just keep a very low rate all the time. If I feel the bottle getting warm, then I make the assumption that it's too much, and I needle it down some more. I'm normally in the 6-7 bar/min camp, but my bottles are more dangerous. __________________ Gilles http://www.dirrebreather.com
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11th January 2007, 02:31	#9 (permalink)
abowie Fighting Girl Current Rebreather/s: Sport Kiss Other Rebreather/s: Join Date: May 2005 Location: Land of Oz Posts: 573	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by GKAM) I think that 200 psi per minute is a bit fast according to standards. Shouldn't the fill rate be 70-100? I know that people do fill that fast sometimes, but 200 psi is a bit too aggressive, no? 4 bar (under 60psi) per minute, especially with iddle biddy Rebreather tanks. __________________ Andrew Bowie Rebreather-friendly Buddy
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11th January 2007, 04:54	#10 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Home Build Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Home Build Join Date: Mar 2005 Location: "Da" Bronx Posts: 2,795	Re: Oxygen Compatible Air Standards (Wallet Card) Quote: (Originally Posted by abowie) 4 bar (under 60psi) per minute, especially with iddle biddy Rebreather tanks. I am actually much more concerned filling big cylinders rapidly, since the high flow rate can give particles significant force.. I'm really not concerned about the cylinder heating (its a huge heatsink), I am more worried about heating at the valve and especially particle impingement.. I don't have a problem if someone is filling very small cylinders even 400psi per minute since there is very little gas flow, but since they are small it doesnt take long to fill them so why not go slow.... but big cylinders even 100psi per minute is high.. __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.
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