Disadvantage of Worthington Steel 100s with Nitrox?

[Puffer Fish]

From what I've gathered in the past, the owner is a very knowledgeable guy and the lead instructor, but I won't argue on his side where the information came from.

However, I am stationed at Fort Hood in Central Texas, Killeen and C&J Divers (a very tiny shop) is the only one in the area so I have no choice. Good people there though.

His knowledge of the regulations seems a bit off though. As what specific regulation he is talking about and remember 3AL is not 3AA.

By the way, I thought the 3,000 psi rule for O2 was common knowledge.

 

[Jim Lapenta]

Uh Oh. Those 3500 psi fills of 32% in my lp 95 and 85's are really gonna be an issue!

 

[Leadking]

CGA only states that anything more than 23.5% O2 be oxygen clean. Get the dive shop upto date or look for a new one.

 

[spyder]

Uh Oh. Those 3500 psi fills of 32% in my lp 95 and 85's are really gonna be an issue!

Now THAT'S funny!

When Nitrox is outlawed only outlaws will have nitrox.....

 

[owlbill]

So there are actual rules and regulations with fill pressures and oxygen mixtures in cylinders.

However, the shop has there facts mixed up a little.
DOT 3AL type cylinders are limited to a fill pressure of 3000 PSI for oxygen service. And "oxygen service" is any gas that contains more then 23.5% oxygen. To put any gas in a cylinder that has more then 23.5% oxygen in it, the cylinder and valve must be O2 cleaned, it must have straight threads, and the valve must be brass or stainless.

Might be a bunch of AL100 and Compact 80s on the market soon as used tanks.
There are no pressure limits listed for an oxygen mixture for any of the 3AA cylinders. And worthington's special permit required to make the HP cylinders does not list a pressure limit as well. The cylinders standard fill pressure limit still applies of course.

Here is a link to the DOT regulations regarding this issue, its CFR 49 section 173.302 paragraph (b) sub paragraph (4)
Electronic Code of Federal Regulations:

Here is a link to the special permit filed for Worthington cylinders SP14157
http://www.phmsa.dot.gov/staticfiles/PHMSA/SPA_App/OfferDocuments/SP14157_2009070249.pdf


Looks like Mike beat me to it, nice post Mike. I posted the actual links to the actual laws that are current and up to date as of this posting for the na sayer's that will now jump out of the wood work.

Right on the money here as far as the correct info goes. There is even a bit on Catalina website about it, but they don't reference the specific regulation.
Oxygen Compatibility in SCUBA Cylinders

Basically, as has been mentioned, 3000psi MAX for any 3AL cylinder, regardless of service pressure, for anything 23.5% oxygen or greater.

 

[rjack321]

This law does not matter much for the run of the mill AL80, there service pressure is 3000 PSI.

But, for the new Neutral AL80 and the AL100 that have 3300 PSI service pressures, this law does apply. I would bet most shops don't even know about this, and if they do they chose to ignore it.

And lets be clear, this is a LAW and not some dive industry thing.

Yes but the OP is talking about steel cylinders with nitrox in them. They only need 300-500psi O2 added if partial pressure blending (depending on mix/pressure/leftover gas etc). The OP doesn't have aluminum deco bottles with 100% or something like that. And the law does not apply to neutral 80s or Al100s where there's nitrox in those either. Unless he want 80cf of 100% in his neutral 80, not really something most divers want.

 

[T. Bix]

I just love it when dive shop owners make up law! I've finally buckled on my 6351 cylinders but on the issue of fills and cleaning I'm looking into setting up my own filling station and servicing my own stuff. I know it's pricey but I can control my own stuff and not have to deal with these ignorant buffoons! I had a well known LDS start citing law to me the other day not knowing that I deal with this stuff every day in my day job........ It drives me nuts!

 

[nitroxfox]

Gentlemen,

These are official interpretations from the DOT and have the effect of LAW:

PHMSA - Interpretations by Regulation - Interpretation #11-0175

"
Q2. What is the maximum pressure to which a cylinder can be filled, when charging the cylinder with enriched air containing elevated levels of Oxygen? Additionally, is this pressure the same for both aluminum and steel cylinders?
A2: For aluminum cylinders used for Oxygen service, including 3AL cylinders, the pressure in each cylinder may not exceed 3000 psig at 21 °C (70 °F) as specified in § 173.302(b). The HMR does not indicate a specific operating pressure for steel cylinders, including 3AA cylinders, used for Oxygen service, thus, the cylinder must not exceed the marked service pressure."

Also from a Catalina cylinder inquiry in 2006:
PHMSA - Interpretations by Regulation - Interpretation #06-0064

Cylinders MUST be cleaned at 23.5%. Aluminum cylinders including fiber wrapped, can only be filled to 3000 psi regardless of service pressure. Steel cylinders cal be filled to marked service pressure with nitrox.

 

[mike_s]

Gentlemen,

These are official interpretations from the DOT and have the effect of LAW:

PHMSA - Interpretations by Regulation - Interpretation #11-0175

"
Q2. What is the maximum pressure to which a cylinder can be filled, when charging the cylinder with enriched air containing elevated levels of Oxygen? Additionally, is this pressure the same for both aluminum and steel cylinders?
A2: For aluminum cylinders used for Oxygen service, including 3AL cylinders, the pressure in each cylinder may not exceed 3000 psig at 21 °C (70 °F) as specified in § 173.302(b). The HMR does not indicate a specific operating pressure for steel cylinders, including 3AA cylinders, used for Oxygen service, thus, the cylinder must not exceed the marked service pressure."

Also from a Catalina cylinder inquiry in 2006:
PHMSA - Interpretations by Regulation - Interpretation #06-0064

Cylinders MUST be cleaned at 23.5%. Aluminum cylinders including fiber wrapped, can only be filled to 3000 psi regardless of service pressure. Steel cylinders cal be filled to marked service pressure with nitrox.

That's awesome info... ..... especially for a 2-3 year old thread.


but the original poster has STEEL tanks.... not Aluminum. :headscratch:

 

[Chugwhump]

I know, I know, I know......
This is clearly a "Zombie Thread" with new legs.....
Buuutttt..........

Aluminum is for beer cans and tuna towers.....
not SCUBA tanks.
Jut sayin'.

Chug
Actually has some AL Tanks.