Question on plus (+) sign on Steel Tanks

[Scott L]

...it's interesting that you are reporting this from Florida of all places ! . .isn't Florida the home of the fabled...the mythical...the magical....CAVE FILL ??? ...heck, I often read how they routinely even fill party balloons to 5000 PSI down there.....

Funny! Cave Country is 200 miles to the north although I am sure there are shops a bit closer that caters to that crowd . Thankfully a very technical dive shop is re-opening soon a bit north of here which will give you 4000 PSI although I am generally content with 3500....

 

[Scott L]

...it's interesting that you are reporting this from Florida of all places ! . .isn't Florida the home of the fabled...the mythical...the magical....CAVE FILL ??? ...heck, I often read how they routinely even fill party balloons to 5000 PSI down there.....

It's funny you mentioned party ballons. I regular poster on TDS has a halarious signature wishing great harm to those that sell and purchase HE filled party ballons with the theory they are contributing to the significant price increase in the gas.

It's difficult to discern your hometown as you do not offer any profile information. Fugitive?

 

[captain]

Good clarification. It was mentioned earler in this thread and the one refrenced that LDS's must calculate wall thickness to gain the + rating. I know of no shop in S Florida that actually hydro's cylinders. They are transported to hydro facilities who perfrom the entire function. That is why I mentioned aerlier to go directly to a hydro facility which are refrenced on DOT's web-site to avoid the inevitable clash with the LDS....

But even most hydro shops can't do the thickness test or the calculations. Unless the tank has the REE stamped on it or the shop has a record of what it is you are out of luck.

 

[Scott L]

But even most hydro shops can't do the thickness test or the calculations. Unless the tank has the REE stamped on it or the shop has a record of what it is you are out of luck.

I am sure you are correct. Fortunatly we have several facilities down here well versed with all issues pertaining to scuba cylinders. As I stated earlier it's really not that big an issue. If a shop overfills cylinders the reslulting PSI is generally greater than the the + PSI. If not, LP cylinders do not make much sence IMO.

 

[WD8CDH]

One of the biggest problems that I have found in getting the + sign stamped on tanks is the 71.2 CF tanks. It seems that the documentation of the REE is lost on all of the manufacturers of those tanks but one.

 

[WD8CDH]

This reminds me that I purchased some new tanks back in the 70's that were DOT3AA that didn't have a + stamp on their original hydro. I was able to get the REE and have them + stamped on subsequent hydros.

 

[duckbill]

Fortunatly we have several facilities down here well versed with all issues pertaining to scuba cylinders.

If those facilities told you this...

The extra step does further stress the cylinder as compared to the normal hydro giving them some arguement.

.....you might think about reevaluating your high opinion of their knowledge base.

 

[WD8CDH]

Since they are absolutly WRONG.

 

[NAM001]

I am a Dive-Con student and my instructor has given me a question that i cannot find the answer to so i am turning it over to scuba board.

Stamped on Steel tanks is the normal markings (manufactur cerial number, max fill rateing, hydrostatic testing date ect...) but on steel tanks only can there be a plus sign. The (+) sign indicates that the steel tank can be overfilled by 10% without causing damage to the tank or blowing a disk. The plus sign indicates this but where did the plus sign origonaly come from ? I have narrowed it down to the DOT haveing a part in it. I hope im on track. Can anyone tell me the orgian of the plus (+) sign?

Thanks in advance
Magicdiver

in wwii the military needed tanks instead of making a new design they put the + sign to get the capacity needed. steel tanks have it al's do not. rehydro normaly is done with out the + recert on it however you can ask to have the hydro done for + cert. the tank preasure/capacity ie 95cu ft is with the + with out it you have a 85 cu ft tank.

 

[oxyhacker]

Though since as I understand it they were all made to the same specification, I would be comfortable using the one steel 72 REE we do have, from PST, for any 72, especially if a tank passed with a reasonable margin.

If you look at the list of REEs for industrial tanks in CGA-5 you will notice that they just list various size and pressures of cylinders and give the REEs, with little differentiating for the various manufacturers or years of manufacture.

One of the biggest problems that I have found in getting the + sign stamped on tanks is the 71.2 CF tanks. It seems that the documentation of the REE is lost on all of the manufacturers of those tanks but one.