O2 cleaned dedicated Nitrox tanks

I have been thinking on getting Nitrox training and have a couple of questions about fills and tanks and what is required. I have read through PADI's nitrox book.

I have read several posts on the board and some say yes you need an O2 cleaned dedicated tank and some say only the Nitrox wrap is needed and preferably the MOD of the fill. I was at my LDS today and they claim that you must have an O2 cleaned tank and must be dedicated for Nitrox. My LDS blends but also has EAN banked and doesn't claimed to be worried about contaminating there air source but claims it's due to the fire hazzard. I would like to find out what is true but I don't know where to get solid info on this.

1. Is there a specific agency that regulates when and under what conditions a Tank can be filled with EAN 40% or less?

2. Does anyone have good links to sites about how nitrox can be filled in a tank and what labels or certs need to be on a tank

3. Are there varing standards for fills if the shop is PADI, SSI etc..etc..

I know your all going to say take the class but I would like to find out as much as I can before hand to determing if I realy want to spend the money on the class and possibly more tanks.

Geek

read Vance Harlow's book "Oxygen Hacker's Companion"...available at www.airspeedpress.com and has about 1000 times as much information as any nitrox book on the market..

The short of it....your LDS is full of it... If they partial pressure blend, then yes, I can see them wanting you to have o2 clean tanks. If they bank nitrox, then all you need is a wrap (and you don't even really need that, but some insist on it). There is so much BS associated with oxygen handling and nitrox these days that I think Vance's book should be required reading for any nitrox course...god knows I wish the dive shops would read it..

Harlow's book will definitely get you squared away..

GeekDiver once bubbled...

3. Are there varing standards for fills if the shop is PADI, SSI etc..etc..

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The only variance is whether your dive shop is stupid or not stupid. As O-Ring pointed out, yours is the former.

Tanks don't need wraps, just a sticker that gives a visual status of the tank VIP and whether or not it has been O2 cleaned IF necessary.
The nitrox wrap means absolutely nothing. Looks kool though.

MD

GeekDiver once bubbled...
I have been thinking on getting Nitrox training and have a couple of questions about fills and tanks and what is required. I have read through PADI's nitrox book.

I have read several posts on the board and some say yes you need an O2 cleaned dedicated tank and some say only the Nitrox wrap is needed and preferably the MOD of the fill. I was at my LDS today and they claim that you must have an O2 cleaned tank and must be dedicated for Nitrox. My LDS blends but also has EAN banked and doesn't claimed to be worried about contaminating there air source but claims it's due to the fire hazzard. I would like to find out what is true but I don't know where to get solid info on this.

1. Is there a specific agency that regulates when and under what conditions a Tank can be filled with EAN 40% or less?

2. Does anyone have good links to sites about how nitrox can be filled in a tank and what labels or certs need to be on a tank

3. Are there varing standards for fills if the shop is PADI, SSI etc..etc..

I know your all going to say take the class but I would like to find out as much as I can before hand to determing if I realy want to spend the money on the class and possibly more tanks.

Geek

Click to expand...

1. Ultimately, the person who fills the tank is the final authority in determining whether a given tank will be filled with any given gas. National or state workplace safety laws may apply in some areas.

2. This should be covered in any nitrox class. As far as you should be concerned, there is partial pressure blending, and everything else.

3. Nope. Not between most agencies. A few do recommend special cleaning for oxygen mixtures much lower than 40%.


If it were me, then I would insist on any tank being blended via partial pressure method to be in oxygen service. If I was filling from a bank or via continuous flow blending, then no special tank cleaning would be needed if the oxygen mixture was less than 40%.

If they both blend and bank, they may have that policy to be certain that they are safe should they need to blend your mixture on the spot instead of drawing from their banked, or if they are out/low on banked EANx.

Technically what you need for EANx fills is:

Nitrox wrap (varies by local regulations, in US/UK, I believe it is a regulatory requirement for recreational diving)
O2 service/O2 clean if getting fills via any meathod that can expose the tank to 40% O2 or higher concentrations.

What you really need is:
Whatever your fill station requires you to have.

A nitrox wrap isn't hard to get on a tank and requires nothing to maintain. O2 service/O2 clean does cost a little every year, but not all together that much. Might as well get it as long as your fill station can provide O2 compatible air at regular air fill costs and not charge you nitrox fills for "EAN21".

As O-ring stated, get Vance Harlow's book from Airspeed Press. It will answer your questions without the agency spin and give you a basis from which you can decide which courses you may which to pursue and give you enough information to make an informed decision about the qualifications of your potential instructors.

Dave D

The only thing I would add here is that some agencies do require that their facilities mark tanks in a mannor compliant with their specific standards.

I require different markings depending on the intended use of the tank. Of course a tank that will have pure O2 pumped into it must be O2 serviced and should have a VIP sticker stating so. A tank intended for recreational (for lack of a better term) use I think should have the wrap (as your book states) and a contents sticker. The wrap lets divers even at a distance know that the tank may contain something other than 21%.

How does that nitrox wrap thing work for doubles? Do most shops automatically consider them technical and let the lack of wraps slide?

Besides being hideously garish, those wraps conceal a large surface area under which rust could develop unseen, so I don't use them. I have 02 clean VIP stickers on both, as well as tape with % and MOD on one of the shoulders.

I haven't had any problems getting fills so far, but wonder if it might cause problems elsewhere.

I don't put them on my doubles. I think there is less of a chance of someone grabbing your doubles by mistake than an al80. I also mark my name on my tanks. My own tanks are just as likely to contain trimix or even air as they are to contain nitrox. I like to have my name, date and Mix (on tape or a contents sticker) on my doubles. I haven't had trouble getting them filled marked in this fassion although that may be because of where I get my fills. At home I do it myself. I get them filled at local quarries and haven't had a problem. The only other place I get fills is in cave country and they will put anything in anything for anyone for the most part. LOL