UW Sports Seattle - Requiring 6" Nitrox Sticker ---ARRRGH!

[Doc Intrepid]

Look, this is silly.

Q. How do you partial-pressure blend nitrox?

A. You place a specified amount of O2 into a scuba cylinder. Then you top it off with air.

You may be using air that is graded in accordance with a more stringent filtration system, but you are adding compressed air into a scuba tank which already contains a specified amount of 100% O2.

Therefore, anyone who tells you that its illegal to pump air into a nitrox cylinder is misinformed.

Thats how you make nitrox in the first place.

Moreover, if for some reason you don't want to breath nitrox, but you don't want to screw up your O2-clean tanks, its perfectly legal to fill your nitrox tanks with the same highly-filtered air and call it EAN21. I don't care how CGA chooses to classify it, no one is going to pull you over and issue you a citation for filling a nitrox tank with the same highly-filtered air that you use to make nitrox in the first place.

But by all means, fill your tanks any way you wish.

 

[lamont]

CGA classifies Nitrox as at least 23.5% O2 (Only some of the SCUBA industry says 21% is still nitrox) and it IS a different classification of gas than air. So diver12345 is ABSOLUTLY correct it is Illegal to put air in a nitrox tank unless the resulting mix has more than 23.5% O2. It is also recommended to remove the valve EVERY time you change the classification of gas that goes into a cylinder. DOT and the US courts use CGA guidelines for case law, so it does hold up in court if it ever comes to it.

The CGA also requires 296 valves and an oxidizer hazard diamond label. I believe there's also a standard cylinder marking which is a checkered tank neck?

It is also illegal to overfill a tank by even 1 psi and this includes overfilling and letting it cool to the proper pressure, but again this is rarely followed.

Nope. Tanks must not exceed their rated service pressure at 21C/70F. Tanks may not exceed 5/4 of their service pressure at 55C/131F. Check 49 CFR 173.301a(d).

 

[dsteding]

The CGA also requires 296 valves and an oxidizer hazard diamond label. I believe there's also a standard cylinder marking which is a checkered tank neck?



Nope. Tanks must not exceed their rated service pressure at 21C/70F. Tanks may not exceed 5/4 of their service pressure at 55C/131F. Check 49 CFR 173.301a(d).

I believe you are wrong here, because this portion of the CFRs applies to shipment of compressed gas cylinders, not scuba cylinders . . . .read (a) of the part you've cited.

I spend most of my life figuring out CFRs, so I'm not willing to dig deeper here. But, one rule in reading regs is to first see if they apply to your situation . . .

 

[MXGratefulDiver]

Each shop has it's policies, good or bad.

There are other alternatives.

Starfish Diving does all kinds of fills and is nearby at Northgate & 15th. Randy has a complete membrane system, does air, nitrox, mixed gases, argon and also tank servicing. He also has technical equipment for rent. He works out of his house, but is completely certified and licensed, as well as being one of the best technical instructors around. You do need to call beforehand to see if he's around.

Starfish Diving

Jack

He also has the best prices for trimix fills, since he only charges for the helium he actually puts in your cylinder ...

... Bob (Grateful Diver)

 

[lamont]

I believe you are wrong here, because this portion of the CFRs applies to shipment of compressed gas cylinders, not scuba cylinders . . . .read (a) of the part you've cited.

I spend most of my life figuring out CFRs, so I'm not willing to dig deeper here. But, one rule in reading regs is to first see if they apply to your situation . . .

yeah, you may be entirely correct, but the filling guidelines only specify service pressure at 70F, no mention of other temps, so it seems ambiguous...

if you fill it at 100F can you fill to any pressure you like so long as you never bring it down to 70F and find it overfilled?

 

[chucknorris]

noo...get the old TDI custom mix stickers. It takes care of it and you don't get the opposite effect which is I don't fill nitrox tanks, even if they are 21%, I don't have an analyzer crap...I know...it doesn't even make sense but sadly you don't need a certification to open a shop.

 

[Travisc]

I deal with Starfish exclusively- Randy will talk you ear off- but he knows what he is talking about and very passionate about the sport/hobby/business- whatever you call it. Hands down one of the top technical people in this are when it comes to diving.

 

[mjh]

My worthless 2 cents... I have dealt with UWS for over 20yrs have found them to be professional and helpful. It's a sticker on a tank for your safety, maybe we are taking rugged individualism a little too far?

 

[ekewaka]

You absolutly cannot put air into a nitrox tank with the big green stickers on it per the law because it is a different classification of gas than air. Ask any well educated PSI inspector. PSI also just requires that the tanks be labeled.

Last time I checked, PSI did not have the the authority to legislate. Only congress can do that.

 

[Mark Vlahos]

My worthless 2 cents... I have dealt with UWS for over 20yrs have found them to be professional and helpful. It's a sticker on a tank for your safety, maybe we are taking rugged individualism a little too far?

I only speak for myself, the cylinders are mine I own them, I paid for them, I use them. In my case they are double 130's, and have my initials on the crown, and my initials in large reflective letters on the sides.

The shop has every right to have a policy requiring stickers, and I have every right to not play in their sandbox.

A large green and yellow band on my cylinders does NOTHING for my safety. A sticker showing the results of the analysis, and the MOD does have an impact on my safety, but this is not the sticker we are talking about. If the issue is that some other diver will confuse his Yoke valved Aluminum 80 with my double steel E8-130's with DIN valves then that confused diver will have far more problems than a gas mixup.

Mark Vlahos