Nitrox and regulator cleaning

[HammerNoMore]

IF, a tank must be O2 clean for anything over 23%, and
IF filling with standard air contaminates that O2 clean status,
Then anyone that gets a EAN fill using partial pressure will need to stop filling their tank and get it recleaned. Partial pressure fills contain all the same nasties that a standard air fill would from that compressor. In fact, a commercial premix would probably be the only viable fill method to keep the tank "clean". I doubt many shops will have a compressor that they use only for EAN fills and a seperate compressor for standard air.

Most quality LDS's filter for grade E air, which will not contaminate your tank.

 

[MikeFerrara]

Mike two minor corections... .

I stand corrected on both counts.

IF, a tank must be O2 clean for anything over 23%, and
IF filling with standard air contaminates that O2 clean status,
Then anyone that gets a EAN fill using partial pressure will need to stop filling their tank and get it recleaned. Partial pressure fills contain all the same nasties that a standard air fill would from that compressor. In fact, a commercial premix would probably be the only viable fill method to keep the tank "clean". I doubt many shops will have a compressor that they use only for EAN fills and a seperate compressor for standard air.

I don't but the whole idea. PADI and NAUI both teach 40% as the limit for needing specially cleaned equipment.

It's not so much the compressor as it is the filtration. Mofied grade E air is recommended for maintaining O2 cleanliness.

Many compressors with their original filter system will produce air that meets modified grade -E but often an extra filter system (hyperfilter) is used also.

I bank air streight from my compressor and stock filtrations system and run the banked air through a hyperfilter when I need to be certain of O2 compatability. BTW, my banked air meets modified grade E standards but the hyperfilter is added insurance.

Contaminants are cumulative and all air potentially contains some contaminants. An exception might be air from a compressor that doesn't use oil but I'm not certain of that.

 

[Sideband]

James and Mike,
That makes sense. Thanks.

Joe

 

[padiscubapro]

IF, a tank must be O2 clean for anything over 23%, and
IF filling with standard air contaminates that O2 clean status,
Then anyone that gets a EAN fill using partial pressure will need to stop filling their tank and get it recleaned. Partial pressure fills contain all the same nasties that a standard air fill would from that compressor. In fact, a commercial premix would probably be the only viable fill method to keep the tank "clean". I doubt many shops will have a compressor that they use only for EAN fills and a seperate compressor for standard air.

I don't but the whole idea. PADI and NAUI both teach 40% as the limit for needing specially cleaned equipment.

Joe

joe, regarless of what padi/naui instructors are saying the ultimate authority is the equipment manufacturer.

No If a store is PP blending they would either be using a different bank that has gone through extra filtration, or all their gas meets oxygen campatibility standards (there is no agreement here what is oxygen compatible).

As Mike said contaminates are cumulative.. They increase over time.. My point about manufacturer standards is that once they are set, if someonegoes against them and something happens it would be hard to defend yourself in court.

There are many shops that are using membrane systems because they didn't want to spend the money to do it right and enough loopholes existed so they possible could get away with it.

I do know a big valve manufacturer is also rewriting its official policy towards enriched air.

I may sound like a preacher but I believe in the stance that ANDI took all these years requiring its shops to maintain top quality gas and follow recognized oxygen handling procedures.

Another thing that comes about as the regs get put on paper, people who are not using manufacturer approved cleaners for oxygen will also be risking themselves if anything happens.. Right now that means using "Blue Gold". There are actually a few better cleaners that have been banned for enviromental reasons..

Mike,
I just want you to know I wasn't trying to be a know it all, just trying to set the record straight... I've only been with ANDI about 5 years now but due to my close proximity with HQ, I have been familiar with ANDI's policies from the beginning (including being a customer in the past for several of E.B. scuba shops)

I remember his main shops fill station, he had all the common mixes banked including trimix way back in the early 90s' . His filtration system was awesome (I actually have part of it and its much more than even the best stores use), Ed had about 60k cu ft of banked gas.

I'm upgrading my system to a oil-free, liquid cooled RIX.. Right now I bank about 2k cuft of oxygen, 16K of assorted banked gases, and do Nitrogen (paintball to 4500psi), Argon, and any trimix/nitrox you need..

 

[Dan Gibson]

The first paragraph is so true. In your second, I'm screwed. I have at least a dozen regs and none are really O2 clean. They get used with 32% up to 100%. Wonder when I'm goin to blow up.

Your LDS is trying to screw you over. I can't believe they would try to pull that over one someone. As long as you're under 40%, you're fine.

If you were going to be breathing a Deco reg with 100%, then yes, O2 clean is definitely the way to go. But just for recreational <40% mixes? Sheesh.

 

[RichLockyer]

For the reg, you don't need anything special for up to 40%. My Nitrox instructor recommended limiting to 39% because the studies on the combustibility show increased "danger" at 40% and up.

I would ignore anything else you heard from this instructor.

Had he actually read the NASA study, he would have found that the actual threshold for evidence of combustion was at around 50%, and the recommendation was for anything over 40% to be treated as pure O2, anything under 40%, treated as air.
Limiting to 39% instead of 40% is simply paranoid stupidity... there aren't many gas blenders that are going to nail the mix that closely anyways.

 

[Charlie99]

There are many shops that are using membrane systems because they didn't want to spend the money to do it right and enough loopholes existed so they possible could get away with it..

Please explain.

Fill Express seems to be willing to spend a lot of money and they use a membrane system for nitrox.

Charlie Allen

(it's past time for this thread to be hijacked)

 

[padiscubapro]

Please explain.

Fill Express seems to be willing to spend a lot of money and they use a membrane system for nitrox.

Charlie Allen

(it's past time for this thread to be hijacked)

I never said all shops.. Membrane systems can be done right (and can save alot of money when set up with the proper filtration), set up wrong it appears you are saving money until its time to prematurely replace the membrane... Alot of shops do buy it to get away the cheapest they can (or so they think).
If you pump a large quantity of mixes around 32% it makes a hell of alot of sense. Personally I rather do continuous blend... In NYC liquid Oxygen is very cheap, It would take quite a while for it to pay itself off in my case.