Help Validate Facts on Overfill to LDS

[Rick Inman]

Augh! Sick of searching, and wading through old threads to try to find some posts I remember, hence this redundant thread.

Can anyone help me with some hard data on this subject?

I was saying to my LDS last night, about overfills, that it's OK to run my LP Steel Fabers over a couple hundred PSI, so they'll cool to the rated pressure. I said that I had read that there is no record of a Faber steel exploding (it's that old batch of AL). I said that I had read that the only detrimental thing to overfilling a couple hundred PSI is the stress on the steel shortens the life of the tank a bit, but that there was no risk to the LDS to put 2800PSI in my 95, so it will cool to 2640.

They said, can I document my postulations?

Can I? Can anyone show me to some data, or a document that validates what I'm suggesting?

Thanks!!

 

[Gary D.]

Just fill it to 5280 and call them doubles.

Some shops will and some won't.

Is it Wayne?

Gary D.

 

[rjchandler]

Augh! Sick of searching, and wading through old threads to try to find some posts I remember, hence this redundant thread.

Can anyone help me with some hard data on this subject?

I was saying to my LDS last night, about overfills, that it's OK to run my LP Steel Fabers over a couple hundred PSI, so they'll cool to the rated pressure. I said that I had read that there is no record of a Faber steel exploding (it's that old batch of AL). I said that I had read that the only detrimental thing to overfilling a couple hundred PSI is the stress on the steel shortens the life of the tank a bit, but that there was no risk to the LDS to put 2800PSI in my 95, so it will cool to 2640.

They said, can I document my postulations?

Can I? Can anyone show me to some data, or a document that validates what I'm suggesting?

Thanks!!

I think if you find something official it will say you fill to 2640 so that it will cool to 2400 I think that was the "original" explanation - but I can't remember where I saw it.

 

[akscubainst]

While most people might agree with you, I doub't you're going to find any documentation saying it's ok to overfill even a little bit. The tank is stamped 2400+ so legally the dive shop should fill it to 2640 and that's it. If DOT or OHSA got their underwear in a knot and decided to go into a shop and check tank pressures the shop could be fined heavily.

From a manufactures liability standpoint, I doubt you would ever see anything from Faber saying "yea, we stamp 2400 but go ahead and fill them as you see fit".

What you really need is for your fills to be slower. PSI recommends 300psi per minute or less.

Dave

 

[String]

Worth noting that the TEST pressure of a steel tank is way way higher than the actual working pressure. That basically means it should survive overfilling below that test pressure, certainly "a few hundred psi" over working.

Example my tanks here are 232 bar working pressure (3366psi) and 348 (5049 psi) bar test.

Any in test tank shouldnt explode below that pressure

FWIW 232 bar was chosen as for air type gases thats where real and ideal gas laws converge - above that they start to drift apart making a reading somewhat inaccurate.

As for "cooling to working pressure". That depends how hot the mix is so therefore how quickly a tank is filled. If its done very quickly it'll be hotter and therefore drop more on cooling than a slowly filled tank.

Another thing to note is if you use A-clamp regs the actual clamp itself is more of a failiure issue on an overfilled tank than the tank itself.

 

[Ray Chavez]

Tanks, no matter what hey are made of, shouldn't fill over their recommended pressure. Now that said if you overfill your tank a couple hundred psi it isn't going to explode (provided that is properly maintained hydro and vis), they constructed to take about 5000 psi before exploding. However regularly overfilling you tank could reduce the lifespan of it.

 

[Al Mialkovsky]

If they aren't filled when full ask them to top them off for you since you paid for a full fill. I have a feeling that putting them back on the hook a couple of times will cure those short hot fills.

 

[Lead_carrier]

But they put 4000 in them in Europe, you just have to stack 2 or 3 burst disk. In Italy they said it was ok.

Heaven forbid that you have the FIRST steel that explodes and it gets found out that it gets found out that it was being overfilled. Any attorney I know would love to have that case.

 

[Wayward Son]

Aren't they willing to let it cool & top it off to the rated pressure? If not, why not?

If they'll do that, the overfill isn't an issue.

 

[String]

But they put 4000 in them in Europe, you just have to stack 2 or 3 burst disk.

You'd be hard pressed to find a tank with burst discs in europe. Im not even certain theyre legal on tanks.