Beware of over pressure tanks

[Da Wolf]

I purchased a LP 121 5 years ago, and allowed a LDS keep/store it for me during that time (since I didn't have room at my place for it). When I moved and got room for the tank, I went to the LDS to retrieve my tank. I then stored it this past winter. It was not used from the time I got the tank from the LDS until this past weekend. It sat full of 32% EAN for 8 months. I hooked my computer to the tank this past weekend, and noticed that the LDS had filled this tank to 3350 PSI. Which is WAY over it's rated pressure. It also has a 2400 PSI DIN valve on it. This could have been a very dangerous situation from being filled way too much. I currently have only 860 PSI left in it. I am taking it to get it's VIP done on Friday and refilled. But I will not be taking it back to the other LDS. I can not believe that they filled a LP tank to HP standards. Needless to say I will never set foot back in that shop. Who knows how many times he has filled it to that kind of pressure. If it fails it's hydro when it comes due, I will do everything I can to have that LDS owner buy me a new tank. So, watch what your LDS are filling your tanks to. A LP tanks filled to a HP tank psi can be a very dangerous tank.

 

[joe8mofo]

There is very little which is dangerous with filling an LP tank to 3350 PSI. I consistently dive LP tanks filled to ~3000-3200 psi without incident. Also have you heard of North Florida cave diving? If you took your tank to a shop in Cave Country they would likely fill it to 3300-3400psi; this is known as a cave fill, and an injury has yet to occur as a result of this practice. I would be more concerned with a tank sitting at that pressure for 8 months and the possibility that it could fail hydro; but as far as safety risk for overfilling an LP cylinder to 3350; there is very little risk.

 

[ScubaFeenD]

Most guys i know who cave dive or have LP tanks regularly fill to 4K to maximize the amount of gas in the tanks. You had a moderate overfill, and I wouldnt be too harsh on the LDS.

 

[Da Wolf]

joe8mofo, yeah if I had of known it had that much in there I would have brought it down to below 3000 psi prior to winter storage. Lesson Learned: Check your tank pressure prior to winter storage.

If a LP tank is rated to 2400 - 3000, and shops consistently fills them to 3300 + what is the point of having a tank rated to a certain pressure? I know people do it to get the most out of their dives, but wouldn't a tank that is not rated for that kind of pressure be more prone to an something happening to it? If we fill these tanks to pressures greater than their recommended pressures, aren't we possibly endangering ourselves? And what is the purpose of the pressure ratings if we consistently ignore them?

ScubaFeenD, ok, so I had a moderately overfilled tank. But when I got my tank the LDS owner had ripped off his VIP sticker from my tank to make me get another one this year. I saw my tank a couple of months earlier with a valid VIP sticker on it. And when I received it, the sticker was no longer there.

 

[Rainer]

You should get in the habit of checking the pressure of your cylinders before leaving the dive shop (you could just have easily been underfilled). Me, I'm usually pretty happy when my LPs are filled to 3400psi. That said, mine rarely stay unused for anywhere near as long as yours did.

 

[spoolin01]

What is a 2400 psi DIN valve? I've seen the ubiquitous 200 bar and less common 300 bar 'specs' which although the DIN rating system seems needlessly convoluted, seem both to be comfortably adequate for even HP tank rated service pressure. The valve may not be such an issue.

It's a shame your LDS was so careless about your tank - makes you wonder what else they might handle in a 'whatever' manner! While it might not represent an acute hazard, it can't be wholly without consequence to the service life of the tank. Certainly many wouldn't want to strap a tank to their back that they feel may be compromised, even if objectively that effect is expected to be slight.

 

[FWADIVER]

Lp tanks are rated to HP in europe. As for danger I believe faber cycles tanks 10,000psi 10,000 times when testing. if anything at least you know a LDS where you can actually get a good fill.

 

[Scared Silly]

LP tanks are rated to HP in europe.

Myth ... different materials same dimensions.

Critical parts are always built with a safety factor. For instance, if a bridge is rated at 100 tons does that mean it will break at 100 tons. No, it was probably built with 1.5 safety factor. As such it will hold 150 tons before there is structural damage. The same for pressurized vessels. I am not sure what the safety factor used to cylinders but I would guess that it is at least 2x the rated fill pressure. Remember the hydro 5/3 of rated pressure so it has to be above that.

Why a safety factor? For just the reasons the OP describes some knucklehead over fills their cylinder. Or for the remote chance that for some reason six 25 ton trucks drive over a bridge at the same time.

Spoolin, you have it correct the valves are either 200 bar or 300 bar - however neither have anything to do with the pressure they can be used at. They only difference is the number of threads.

 

[Leadking]

Bullsh**!!!
From a post I did in 2005

Quote:
Originally Posted by divernate
aren't the fabers filled to 4000 and higher across the pond? the DOT knockes the pressures down. I put 4000 in mine with 5000psi disks.

I will repeat the following statistics, that I seem to post on a montlhy basis;

Faber makes no tank greater than 7 inches in diameter that can take 4000 psi under any regulation anywhere in the world

U.S.tensile strength for 3AA cylinders (105,000-125,000 psi) is not the same as European tensile strength (135,000-155,000 psi as required by EN 1964 part 1 and ISO 9809 part 1) and I have test data that shows Faber cylinders delivered to us show a tensile strength of 115,000-123,000 psi (as required by DOT)

You can verify my info my registering at Scubadiving cylinders Faber leader in scuba diving cylinders Faber steel cylinders, diving, scuba, diving cylinders, diving cylinders, diving cylinders, scuba diving cylinders, sub SCUBA scuba DIVING and reviewing the stats yourself.

Lp tanks are rated to HP in europe. As for danger I believe faber cycles tanks 10,000psi 10,000 times when testing. if anything at least you know a LDS where you can actually get a good fill.

 

[SoBay Jim]

I purchased a LP 121 5 years ago, and allowed a LDS keep/store it for me during that time (since I didn't have room at my place for it). . . . If it fails it's hydro when it comes due, I will do everything I can to have that LDS owner buy me a new tank.

I don't know of any shop around here that provides storage for its customers. What was five years of storage worth to you? A quick search at publicstorage.com shows the cheapest space would cost $56 a month. That's over $3,000 for five years. Add to that the convenience factor of not having to lug and load it from home to the shop for fills and I'd say you've got one great LDS.

Also, you say you don't know how many times it was filled to that level. Was it in the LDS rental rotation? If not, then you should be able to look at your log book and tell EXACTLY how many times it was filled and to what level.

Just my $.02, but I wouldn't be complaining.