Printable View
can someone tell me what the time limit is for getting LP tanks overfilled? will those shops that are willing to overfill generally stop doing it if a tank is past it's first hydro? weighing this in as a factor on HP vs LP tank purchase. i live in Jersey, and so far gather it's not easy to get LP tanks overfilled here at all (let alone after one or two hydros).
jeff
Can I be real blunt here? The LP versus HP debate has been resolved by the new regulation stamped E8 series tanks. Most popular are the E8-130's which are essentially the old LP Steel 104's. The difference is the new E8 series is rated to 3460 psi. No more hassle with the local rec dive shop about overfilling crap. DON'T waste your time buying LP or HP. Go brand new E8 series. Save your money up until you can afford them. It will save you a lot of hassle.
If you are talking about the +10% overfill of steel tanks - they can continue to be overfilled the 10% (2400+240=2640) thru the orininal hydro. After that you have to get them hydro tested specifically for the 10% overfill. Supposedly it's just a matter of finding a hydro tester that can do the test (and passing the hydro within spec).Quote:
Originally Posted by jeffb78
The + hydro can be redone indefefinitely; it is simply a matter of the test facility being set up to do the additional exansion test and the cylinder passing. Even if a + cycle has been skipped for whatever reason, if a facility tests and the cylinder passes it can be stamped with the + rating again. As for shops overfilling, most give no credence to cylinder age as long as the cylinder is in good condition. My favorite fill operator always answers the question, "How high can you fill it?" with the response, "How high do you want to take it to?" Overfilling will reduce the overall life cycle of the cylinder, by exactly how much is pretty much conjecture at this stage in the game.
LP cylinders offer the advantage of being able to get a full fill from fill stations not set up to pump beyond the 3000psig pressures common to recreational set ups. If your local fill stations can easily fill the higher pressure mid range cylinders, then they may be your best bet as you will have an easier time getting them filled to rated pressure than getting the LP's overfilled.
thanks for the advice!
I use Faber tanks. They are lighter than the Pressed Steel and easier for me to carry out of the water.
Are there any Faber type (weight) tanks that have the rated fill pressures of the new E series tanks?
Richard
Faber does have the new FX series tanks which are rated at 3442 (like the E series from PST). Unfortunately, the weights (on land) are pretty much identical to the PST's though.Quote:
Originally Posted by Puttzer
I have a set of doubled PST LP95's and a set of doubled Faber LP95's. I'm with you...out of the water, the Fabers (doubled up) are 13lbs lighter on land.
Richard,Quote:
Originally Posted by Puttzer
It is interesting to note that when Faber tanks were originally imported to the USA by Cressi-Sub over 15 years ago they had no DOT stamp and and a rated fill pressure of 200b or 3000psi without a 10% overfill. When Scubapro began importing the tanks they had a DOT stamp and were derated to 2640psi with the 10% overfill....same tank just derated to fit existing regulation and a change in color from yeloow to white. When OMS put their name on the Faber tanks the color changed from white to grey but not the fill ratings.
The Faber tanks are still sold in Europe today with a 200b rating and typically filled to 232b...a little over the 10% overfill.
So, the Faber tanks are engineered to withstand 3000ps1-3500psi fills as routine duty. It is only manufacturers jumping through goverment regulatory hoops that have them derated, not safety issues.
Kind of like the need for burst disc in valves...but that is a whole different can of worms!!!
Lee
I have heard so many different versions of this tale that it is hard to know what to believe these days. Seems like most folks say that the cylinders we have here and those in Europe are exactly the same, while others state that there is a difference between the two and thus the US cylinders are not capable of being repeatedly filled to the much higher pressures; different alloys and different specs such as wall thickness seem to be the most offered variances that I have heard. I have been filling my Fabers to typical "cave fill" pressures and have yet to notice any problems with them, but it would be nice to be able to read some "official" report to know which version of the marketing story is true. Do you know of such a source Lee?Quote:
Originally Posted by lonestarfl
You own a fair sized manufacturing company. You make these steel things that people put gas in. I guy comes along and says will you make me 500 of these thing about this tall? Sure you say but hey can I sell them to other folks I hear thay like these in America too. Sure the guys says.... But I hear the DOT in America only lets you fill them 3/4 of the way so you will have to build two types.......... Um ok I'll do all that R&D to meet a lower standard than here in Italy....... Sorry it don't make fiscal sense they make one cylinder and stamp one for America and one for the smart people. Of course then they go and lose their minds over the types of gas and want everyone to use a different valve for each one :wink:
I tend to believe they make one cylinder and label accordingly
The cylinders supplied to the US market are different to those supplied to the European market. I do not know whether there are differences in wall thickness but the pillar valve threads are certainly different. Presumably metric versus dare I say 'imperial'.
Result, a brand new US DOT Faber will automatically 'fail' if presented for hydro here in the UK just as a European Faber would 'fail' if presented for hydro at a US test station.
With regard to pressures the steel cylinders marketed in Europe fall into 2 groups, 232 bar working pressure and for the last approximately 10 years or so 300 bar working pressure. In both cases that is the wp marked on the cylinders, not sure where you got the idea that European 232bar Faber were actually 200bar over filled to 232bar. The US cave policy of over pressing tanks tends not to occur over here. With 300bar cylinders readily available who needs to!
Plus of course we do not have burst discs but that is a whole other story.
Peter
You are aware that 300BAR is almost 4500psi?Quote:
Originally Posted by Pete
Other than firefighter and paintball cylinders (fiber-wrapped aluminum), I don't believe I've ever seen a 4500psi cylinder. Perhaps you're thinking of E-series? They are 3442psi (232BAR).
Russell
Wait a second - are you from Connecticut or the UK?
It does not make a lot of sense to me either for them to manufacture two cylinders so similar yet different. But as you can see, there are those who insist that there are differences based upon the geographical market they are intended for, which is why I would like to read some sort of official technical document regarding this. The different threads is a new one to add to the list of why they differ.Quote:
Originally Posted by curtschu
I have an OMS catalog from early 2000-2001. That's back when they praised virtues and the superiority of the Faber LP tanks as opposed to HP Tanks from other manufacturers. Now they've done a complete reversal that I'm told has more to do with a falling out with Faber as opposed to an actual improvement in the tanks.
In this particular catalog the Tank Specs Chart gave a Working Pressure of 2640 which included a 10% overfill but rated all of the Tank's life spans as 10,000 Fill Cycles at 4000 psi. That gives the impression that you should be able to fill these LP Tanks to 4,000 psi 10,000 times but...........you probably shouldn't.
It's difficult to know what to believe as there are conflicting stories.
Maybe we should all just fill to what the Tanks max rating stamped on the tank and stop living so dangerously. :wink:
I've started wearing a Bomb Squad Suit just to ramp mine up to 3,800.
When I joined the forum I was living in Connecticut, now back in the UK. Just never got around to changing my profile.
As to pressures, yes 300 bar works out at about 4350 psi. The 300 bar steel cylinders have been pretty common over here for 10 years or so. Only problem when they first came on the scene was that the high pressure seats on some regs did not like the pressure despite in theory being cleared for 300bar. We use Apeks and absolutely no problem with 300bar
And if 300bar is not enough then the diluent flasks on certain UK military rebreathers are rated for 350bar!
Only problem with such pressures is that beyond approx 240bar the gas laws start to deviate a little. Result, our 12.5 litre 300 bar twins when 'full' contain a little less usable gas than the 7500 litres (approx 260cuft) you would expect.
Peter
PS. even at 300bar, still no burst discs!!!!
Mine don't have the max pressure stamped on them, just the turnaround pressure. Isn't that what 2400t means?Quote:
Originally Posted by Caveranger
If turnaround is 2400, then we fill them to 3600.
:wink:
That means with a + hydro you would round up to 2700, which would make a 4000psi fill just about right :P I like the way you think Russell 8)Quote:
Originally Posted by Sludge
Darn, you misunderstood my joke. I was implying I saw the 2400+, and misread it to be 2400T, T for turnaround.
Yes, I understand a +hydro.
I fully understood your joke and the twist on the +, just rationalizing my own preferred fill pressure :roll:
I have read so much debate about tanks on the net that I just fill my 104's to 10,000 psi, turn at 6,600, and do my deco with the left over 3,300 during an OW dive the next week !!!! So much for my cavern training.......
My source is that in 1985 I used a pair of Cressi-Sub yellow 108's. These were Faber tanks and did not have a DOT stamp. They were purchased in Miami by a fellow cave diver and light builder, Bob Duncan, and some of the first Fabers in the US. They were stamped 15 L and 200b....we filled them to +10%, 3200psi. A few years Later Scubapro imported these cylinders in white with DOT stamp. To comply with current DOT specs/approval they had a rated fill pressure of 2400psi which gave 95cuft at 2640. These tanks were then imported by OMS in grey.Quote:
Originally Posted by DeWayne
I dive in both the US and Europe. I can promise you that the Faber tanks are the same steel on both sides of the Atlantic. The size, weight, and bouyancy are identical. The differences are color and stampings except that tanks with valves in Europe have no burst disc. In Europe the tanks are marked in liter capacity, and bar fill pressure with a CE approval.
In the US the tanks are marked in cuft, psi fill pressure and DOT approval.
In Europe there are heavier tanks that are rated to 300b by Beauchat and Heiser. But there are only a few first stages rated to handle 300b and limited dive shops that bank +300b for filling.
In addition to these European tanks there are the HP steel tanks from Japan by Asahi which are rated at 3500psi and have the 5/8" tank thread.
The new PSI steel tanks rated at 232b are a new DOT class/approval. I don't know if the alloy has changed, but I can tell you that the weight, size and bouyancy of this new E-series has changed minimally. They may have just retested and uprated the old tank design at a highter working pressure.
I have yet to have much exposure to the Worthington steel tanks.
I am giving you the facts as I know them from my experience. If you have further questions let me know.
Lee
OK, now that I'm really confused I decided to contact Faber directly. Here is what they told me by email:
"When we receive an enquiry like yours one regarding our cylinders, in order to be precise we need to have the serial number of the cylinder(s) the sender is referring to.
Generally speaking the threads of the cylinders we sell in Europe are normally requested to be M25x2 DIN 477 or a M25x2 EN 144-1 while normally the thread of the scuba diving cylinders we have been selling and we are selling in the US market is requested to be a 3/4"-14-NPSM CGA V1.
Concerning the manufacturing standards, the cylinders we sell in the US market must comply with the DOT 3AA standard.
In Europe there are different European standards and also national standards that may vary country by country even though since June 2002 the scuba diving cylinder sold inside the European Union must comply with the European Directive 97/23/EC Pressure Equipment Directive. However the standard DOT 3AA is not among the ones used and/or allowed in the different European countries.
A comparison among the different manufacturing standard is in any case practically impossible."
So I guess the next question is: how does the standard DOT 3AA compare to the European Directive 97/23/EC Pressure Equipment Directive?
Ok, I give up.
Below is the second reply I got directly from Faber. FWIW, they are nice to take the time to reply and I appreciate that. Some of you may be able to better "word" your questions. Just wish I could ask more directional questions that could get more direct answers. (I didn't think asking them if I can overfill my US tanks, would get a candid answer.) But here 's their last response.
"As I wrote you in my mail of today the cylinders we sell in the US market are manufactured according to the DOT 3AA standard (recently we got also a DOT exemption so we sell also DOT exemption cylinders).
The cylinders we sell in Europe are not manufactured according to DOT 3AA or DOT exemption standard.
"