tank size and pressure

[NAM001]

That is the part they say they are not trained to do. And they won't, even if the REE is stamped on the shoulder of the cylinder.

From my understanding the condition of getting the plus renewed is the same test results. You look at the result asn copare it to a calue and it is a pass or no pass. if it passes compare it to anther to see if it passes teh + criteria. My tanks are about 2000 and newer. all pass the + criteria but the hsop dies not put the + on the tank.

 

[dead dog]

We use LP 2400 psi steel cylinders here in north Florida and fill them to 3800-4000 psi.

Let me know where to send the flowers.

 

[BRT]

Let me know where to send the flowers.

Believe me, you can afford flowers for all the people who ever died from exploding steel scuba tanks that were in hydro and vis.

 

[W W Meixner]

I think all that you said is fine. Except Not every one can afford a RB, or have the other issues you suggest. I dive LP's and I over fill them. One large 120 over filled tank lasts me all day in the local shallow diving areas. In places where air is not cheap it makes a difference. There is a lot of simplilcity provided in over filling. Is it the thing every one should do. should AL80's be filled to 120, probably not and I would myself would not. Steels , some more than others,, have proven their tollerance for over filling. If some moron in washington decided that any tank over 2000 psi is the same as an automatic weapon everyone would be paranoid of lp's being filled to 2200. All some one has to do is make or change a standard such as the tank needs to be able to pass a hydro after 5k fills to a test PSI. and if that psi instead of being 10k fills to 4k turns out to be 5k fills to 6K then working pressure just took a leap. and the construct of the tank does not change a bit. If a faber tank has a blow up point of about 10K there is a lot of work done in the background to reduce the normal fill psi to 2400. Thats 7600 psi of pressure safety buffer. I suppose that if a tank with x psi in it was sin a fire of 3000 F and the bow plug failed there would be a nominal threat of a tank rupture. But I dont dive in a burning building and If I take my tank to a shop it will be near empty and no threat to anyone. Safety regs are seldom made for reality or even enforcement. they are made for the extreem combined conditions and are enforced only after and incident. If My hydro guy can presurise my lkp steel to 4K and the maker says it can have that done 10,000 times with out a hydro failure then I can surely pump them to 3500 for an hour or two.

KWS...

I like the part where you said...''All that you said is fine''...

Your all day ''shallow diving'' fill can be accomplished just as well with a HP 133/149/double 80's/double 100's...with no need to overfill...

Take LP out of the conversation...LP/3000 PSI/HP...over-filling is over-filling...it should not be done...it should not be advocated...

The shops that are enabling you are the real problem...they're jeopardizing their staff...customers who may be in the fill area...not to mention their liability insurance...

Please...feel free to proceed as you see fit...

W...

 

[victorzamora]

KWS...

I like the part where you said...''All that you said is fine''...

Your all day ''shallow diving'' fill can be accomplished just as well with a HP 133/149/double 80's/double 100's...with no need to overfill...

Take LP out of the conversation...LP/3000 PSI/HP...over-filling is over-filling...it should not be done...it should not be advocated...

The shops that are enabling you are the real problem...they're jeopardizing their staff...customers who may be in the fill area...not to mention their liability insurance...

Please...feel free to proceed as you see fit...

W...

So the tank manufacturers are okay with it, but you're not?

Can you please provide a single case of an overfilled LP Steel cylinder (in hydro) exploding? There are hundreds or thousands of cave-filled LP tanks in FL cave country....so if the danger you're worried about is there, there will be examples.

 

[W W Meixner]

So the tank manufacturers are okay with it, but you're not?

Can you please provide a single case of an overfilled LP Steel cylinder (in hydro) exploding? There are hundreds or thousands of cave-filled LP tanks in FL cave country....so if the danger you're worried about is there, there will be examples.

Victor...

Hydro/re-hydro is a practise/process/procedure which is manufacturer acceptable...conducted by trained professionals...using specialized equipment with built-in safety factors...for very short periods of time...filling a LP cylinder to 200% of its WP and diving with it is not acceptable by any scuba cylinder or scuba cylinder valve manufacturer...there is a difference between a service ''test''...and daily practical application...

Accident case history has already been provided on SB regarding this subject...suggest looking through the archives...

W...

 

[victorzamora]

Victor...

Hydro/re-hydro is a practise/process/procedure which is manufacturer acceptable...conducted by trained professionals...using specialized equipment with built-in safety factors...for very short periods of time...filling a LP cylinder to 200% of its WP and diving with it is not acceptable by any scuba cylinder or scuba cylinder valve manufacturer...there is a difference between a service ''test''...and daily practical application...

Accident case history has already been provided on SB regarding this subject...suggest looking through the archives...

W...

Firstly, 3600psi is not 200% of the Working Pressure, it's 136%-150% depending on your tilt.

Secondly, I'm not talking about "safe during hydro", I'm talking about representatives from Faber saying that it's fine to cave fill their LP85s, LP108s, and LP121s, among others.

 

[Storker]

So, just to clarify some things for me: Would you mind calculating and posting the true amount of gas in a tank with 17L internal water volume at pressures of 100bar, 150bar, 200bar and 242bar with EAN32 and Tmx 10/70?

No can do. I can, however, calculate and post the amount of gas predicted by the van der Waals equation.

@Storker to add to @victorzamora 's request, since I assume the values quoted by Faber are air and the chart I was referencing was in air, if you could post that as well.

Keep temp at 300K as well. Cave country probably averages 80F anyway

Good thing I've been geeking out with a spreadsheet earlier, since that saved me about a ton of time. Using the most recent values for the van der Waals constants that I have available (CRC Handbook of Chemistry and Physics, 63rd Edition, 1982-1983) I get:

It's probably easier to see the trends from a graph:

Now, @tbone1004 's post with the compressibility numbers made me a little concerned. Because although he'd gotten them from Wikipedia, Wikipedia had lifted those numbers from Perry's Handbook of Chemical Engineering which is sort of the bible for data like that. And those numbers didn't fit very well with what I calculated using the published values for the vdW constants - even though my data fit rather well with the curves in my gas blender textbook (which had been generated using the vdW equation and those same constants). So I geeked out rather seriously yesterday and found some old-ish data for the compressibility of He and of He-N2 mixes. Having data for air (taken as EAN21), pure He, pure N2 and a He-N2 mix I could fit my own constants by hand. That gave a somewhat different set of data:

And the graph:

 

[W W Meixner]

Firstly, 3600psi is not 200% of the Working Pressure, it's 136%-150% depending on your tilt.

Secondly, I'm not talking about "safe during hydro", I'm talking about representatives from Faber saying that it's fine to cave fill their LP85s, LP108s, and LP121s, among others.

Victor...

Please post a copy of Faber's ''cave fill'' over-fill approval document...allowing up to 150% of WP...not including over-fill approval during hydro/re-hydro procedures...an overfill approval document from Blue Steel...Faber's preferred valve would also be appreciated...

Best...

W...

 

[Degenerate]

Victor...

Please post a copy of Faber's ''cave fill'' over-fill approval document...allowing up to 150% over WP...not including over-fill approval during hydro/re-hydro procedures...an overfill approval document from Blue Steel...Faber's preferred valve would also be appreciated...

Best...

W...

Its not 150% over WP, its 50% over WP.

It is 150% OF the WP however, but thats a big difference and its not what you said.