Bad memory? O2 Clean required for less than 40% nitrox

[boulderjohn]

Now, I recently got tanks from Faber that were "O2 cleaned for premix EAN" but they, Faber, wouldn't allow the dive shop to label it as O2 cleaned in their VIP.

1. Faber has no control over the valve that is used on the cylinder, and the valve is the most worrisome part of the O2 cleaning process. Under CGA rules, a scuba valve is not suitable for oxygen service. Thermo valves tell you flat out that they cannot be used for mixes greater than 40%, and if you call and ask them about that, you can almost hear them winking as they explain it.
2. If Faber tells you it is O2 clean, you put O2 in it, and something happens, they will be at fault. If you clean it and something happens, it will be your fault.
3. An O2 clean cylinder is O2 clean for any mix.
4. The rules regarding O2 are such that you will almost certainly violate some rule if you are working with O2 with scuba cylinders, so if you are doing so, you are running a risk. The question is where you draw the line on that risk.

 

[iyakonboats]

1. Faber has no control over the valve that is used on the cylinder, and the valve is the most worrisome part of the O2 cleaning process. Under CGA rules, a scuba valve is not suitable for oxygen service. Thermo valves tell you flat out that they cannot be used for mixes greater than 40%, and if you call and ask them about that, you can almost hear them winking as they explain it.
2. If Faber tells you it is O2 clean, you put O2 in it, and something happens, they will be at fault. If you clean it and something happens, it will be your fault.
3. An O2 clean cylinder is O2 clean for any mix.
4. The rules regarding O2 are such that you will almost certainly violate some rule if you are working with O2 with scuba cylinders, so if you are doing so, you are running a risk. The question is where you draw the line on that risk.

Yes, hence why I created that baseline with a valve that is "Nitrox service ready", it's the conundrum between the CGAs rules and what has been widely accepted practice for a very long time. I can see where the confusion now comes in, as CGA states the 23.5% rule, but the widely accepted practice in SCUBA has been not mandating O2 cleaning unless you're doing partial pressure fills or require 100% O2.

This was primarily where my confusion started, because I don't just accept something without evidence or the reasoning behind it, I drove my 6th grade teacher insane about why Pi was 3.14 and non-repeating and non-terminating, something no one ever asked her in all her years teaching, so for people like me, especially once we move past what has been taught to us about O2 cleaning requirements in the past, one can't just do a 180 and just say "it's the way it is", when instead one could simply say they're following a more strict standard that sets the bar for O2 cleaned tanks at 23.5%.

Without a comprehensive study around accidents involving the fill of SCUBA tanks using either banked EAN, partial pressure filled, or just 100% O2 filled, and what the root causes were, it'll aways be a grey area of whose fault is it and who is liable. So, perhaps as an industry they err on the side of caution and just require O2 cleaning for anything beyond 23%? I mean, how much more money would one really be spending? If this became the norm with all shops doing it, the price should/could be driven drown due to competition that it becomes inconsequential... perhaps?

 

[Jcp2]

My impression for my experience is that one shop is sticking with the 23.5 rule and the other with the 40 rule (which was what was taught to me in PADI nitrox by that shop). Has PADI changed its teaching practice? I don’t know, but from a cost standpoint, if you start with new tanks and new valve to the first shop and always get your VIP at the first shop, the cost would be an extra $5 per VIP, and an extra $40 for the valve rebuild at hydro, and an extra $70 for tank reclean at hydro. How does the shop ensure that you’ve only filled at their shop between VIP. ¯\_(ツ)_/¯

To get a conversion from a in hydro non clean tank to a clean tank with a air fill would be $25 + $40 + $70 = $135 and I would have to wait 2 weeks. To buy a used in hydro tank from them that is filled with air, already O2 clean and in VIP (as they treat all their own tanks that way) would be $150 but available immediately.

 

[boulderjohn]

Over the years, I have gotten my helium and my oxygen from 3 different sources, and in every case, I got the supply bottles from a mammoth warehouse with untold hundreds of supply bottles of different gases. My purchases of helium and oxygen barely amount to a blip on the radar screen of their annual sales.

Those are the people for whom the CGA rules were made. I doubt that anyone gave a passing thought to the needs of the scuba industry when any of the current rules were enacted.

 

[rob.mwpropane]

So, even for banked EAN they require O2 cleaning?

I second a question someone else had, how can you be O2 cleaned for banked EAN only, as compared to O2 cleaned for 100%. Let's keep all factors to a brand spanking new tank, no hydrocarbon based lube, and O2 rated orings, and your standard valve ready for 40% Nitrox service, as our baseline. Now, I recently got tanks from Faber that were "O2 cleaned for premix EAN" but they, Faber, wouldn't allow the dive shop to label it as O2 cleaned in their VIP. So, it begs the question, is there some difference between "O2 cleaning for premix" and "O2 cleaning" in general (to accept 100% into the tank for a pp fill)?

Is there some wild assumption that everywhere you go will always have banked EAN, or they'll partial pressure fill in their own cylinders before putting the final mix in yours? What about enriching a mix and using O2 to accomplish it? It's been widely accepted you don't need O2 cleaning for banked <=40%, so what changed with Faber and their stance? (Mind you, this is what the dive shop told me).

Now, I don't buy that an O2 cleaned tank will maintain that exact degree of cleanliness through it's one year VIP cycle, unless you're getting fill from somewhere with air so pure it makes the baby Jesus' breath smell like a fart, it's very likely you're introducing trace amounts of contaminants. Would it be safe to agree that it's likely the contamination points likely to introduce hydrocarbons into the tank are likely the grease used? Not saying only, but perhaps the biggest contributor to contamination is likely that?

First off, you have too much common sense, best not to argue with any LDS... you could try but you'll probably fail at getting what you want and really just piss them off.

It still falls back to the one golden rule; their shop, their compressor, their rules. That trumps all.

 

[Cio]

Anyone who thinks there is a danger in filling a tank with up to 40% from a bank, could be dangerous is not thinking this through.

Nitrox sticks send this mix through a compressor which has fuel, heat and velocity, basically the most violent environment you can imagine. If there was a way for this to go, compressors would be blowing up like mad. Filling a tank as fast as you can won't even come close to simulating the conditions that gas goes through during compression.

 

[iyakonboats]

First off, you have too much common sense, best not to argue with any LDS... you could try but you'll probably fail at getting what you want and really just piss them off.

It still falls back to the one golden rule; their shop, their compressor, their rules. That trumps all.

Yeah, I'm cool with that, but I think customer service is lacking at a lot of dive shops these days and when it comes to tank fills, offering a valid explanation like "We adhere to the 23.5% standard to make everything and everyone safe", in which case, ok, cool. But being a USDA grade A d!ck about things and saying "that's the way we do it" means I'll take my thousands of dollars I spend yearly in this sport, along with my loyalty, elsewhere. But hey, it's their shop, but it's also my money. People seem to forget, when you go home and turn that light switch on and the lights come on, it's because your customers give you money to pay your bills. Hell, I never ask for much, just respect and customer service, but that is becoming non-existent today with all the d!ck swinging.

 

[Divin'Papaw]

Anyone who thinks there is a danger in filling a tank with up to 40% from a bank, could be dangerous is not thinking this through.

Nitrox sticks send this mix through a compressor which has fuel, heat and velocity, basically the most violent environment you can imagine. If there was a way for this to go, compressors would be blowing up like mad. Filling a tank as fast as you can won't even come close to simulating the conditions that gas goes through during compression.

That is something I've always considered as well. Problem is, as has been said, shops that stick to the 23.5% rule don't care about logic. The owners of these shops. for whatever reason, have come to the conclusion that this is the regulation and no one is going to change their minds. I have stopped trying and just take my business elsewhere. In my neck of the woods (South Florida) I can get banked nitrox fills a MANY locations without having O2 clean tanks. There is ONE shop that is the exception. I just don't get my fills there.

 

[Marie13]

The "yellow and green label" is frustrating to say the least. Only found one shop near me that needed it. I don't get my feels there anymore since they started that rule.

The shop near my office (where I’ve been working since March) requires the big yellow and green label. Refuses to fill without it. I questioned the shop owner further and it had nothing to do with my tanks coming from DGX with their sticker. If I had brought in tanks VIP’d at another shop with the usual smaller VIP sticker, no good. Guy actually showed me the PADI nitrox book and pointed to a picture of tanks with the big yellow and green sticker. Guy wasn’t happy when I told him not everything PADI says is true, but I caved for convenience sake. 10 minutes vs 60 minutes for fills?

 

[Scared Silly]

Something folks forget ... dive shops carry liability insurance. Insurance underwriters make rules which includes following industry standards. While rare, if there is an issue, and if the shop is found not to be following the industry standards then the insurance company is not going to payout. So next time your are in a shop that is following the CGA rules maybe it is because they are concerned about the potential liability. So give them a break.

The other to consider, the conversation of 40% has been going on for at least two decades. As such, one has to seriously wonder why the cylinder manufactures and the scuba industry have not worked with the CGA to create a 40% standard??? It would be in everyone's best interest to have consistent standards. But perhaps there are issues they most do not know about or understand.