26 replies to this topic

[Dive_Girl]

Exactly. I know you're aware, but to make it clear for those who aren't. The + has to be stamped at the time of the latest hydro to be valid.

I was aware of the "+" (thank you for the explanation of the "+" for this thread ) but not aware that my tank is stamped with that, so that means the listed pressure +10% is the working pressure needed for 80 cuft. So what if my steel tank HP 80 was not stamped with a "+" when produced, and it is filled to the listed working pressure (say 3500 as listed in the charter above) it will always be less than 80 cuft? So why list 3500 as the working pressure and sell it as an 80 then?

[Walter]

My guess is marketing.

[PerroneFord]

Exactly. I know you're aware, but to make it clear for those who aren't. The + has to be stamped at the time of the latest hydro to be valid.

I was aware of the "+" (thank you for the explanation of the "+" for this thread ) but not aware that my tank is stamped with that, so that means the listed pressure +10% is the working pressure needed for 80 cuft. So what if my steel tank HP 80 was not stamped with a "+" when produced, and it is filled to the listed working pressure (say 3500 as listed in the charter above) it will always be less than 80 cuft? So why list 3500 as the working pressure and sell it as an 80 then?

HP Streels don't have a "plus" system. If the working pressure of your HP80 is 3442, then that is what it needs to be 80cuft. The plus system IS used on LP steels so a LP95's working pressure is 2640psi but without the plus it can only be filled to 2400psi legally. Some older LP stessl are 2200psi tanks. There are also 3000psi steel tanks so you really need to watch the pressures.

-P

[gcbryan]

And you're usually so exact and through in your answers Walter.

Perrone's right and you're wrong.

Next question....

Edited by gcbryan, 21 August 2006 - 07:19 PM.

[Walter]

Yep, I messed up. Nicolle was asking about HP and I was giving LP answers. Sorry.

[Dive_Girl]

Yep, I messed up. Nicolle was asking about HP and I was giving LP answers. Sorry.

OK PHEW! I didn't recall my HP 80s having + or thinking that my dive shop would be shorting me in fills and I just got to the shop to look, but y'all just saved me the time.

Still good info to know about the difference with LP 80s, because as I recall (an correct me if I am wrong here) isn't it likely that on subsequent hydrotestings that the tank will lose the + rating?

[6Gill]

So how about the terms DIN and Yoke? You'd be surprised how many people out of OW forget the difference between the two or that there are even two and why it even matters. Some people tend to just know what they dive (and some may know what they dive yet forget the proper term).

Why does it matter? How about:

When you are renting a tank - you want to make sure you reserve the right valve/tank for your regulator
(or the reverse)
When traveling you want to make sure you have the proper regulator for the tanks you will be renting or know how to ask for the options
(or)
When renting both regulator and tank, you may want to get the one you are used to assembling/diving

So who's up for explaining the differences between the two, perhaps even the history behind them, why there are the two, when a diver would select one over the other, and can one be converted into the other easily?

Has the makings of its own thread me thinks...

Another aside. The standard OC tank in Europe is the 12 litre steel. The standard in the US, the 80cu.ft. aluminum, is around 11 litres. So the European tank contains about 9% more than the US one.

So Peter do you think DG is ready for a lesson in the use of L and Bars for the meaurement of tanks aka bottles?

Still good info to know about the difference with LP 80s, because as I recall (an correct me if I am wrong here) isn't it likely that on subsequent hydrotestings that the tank will lose the + rating?

A standered hydrostatic test wouls not include the 10% + factor.You can ask to have it done but not all places will(or want to) perform this added test.

I suggest people look into a PSI Vip course(1 day) even if you don't plan to vip your tanks there is a lot of knowlage one can pick up.

[Walter]

I recall (an correct me if I am wrong here) isn't it likely that on subsequent hydrotestings that the tank will lose the + rating?

Almost any LP steel tank that passes hydro should be able to get the plus. There are several practical problems with actually getting the plus. Many folks doing the hydro actually believe the plus is only available at the first hydro (at the time of manufacture). Many don't know how to do the extra math (that's all it is - extra math) to give the plus. Some simply refuse to give the plus.

[Dennis]

Walter's got it right on that one. It depends on the hydro facility.

Taking a Cylinder Safety Inspection course from PSI or Diving Technologies International is a good idea. Then you can safely and confidently inspect your own cylinders. However, to do a Vis Plus on the older aluminum tanks, you have to purchase an expensive eddy current tester. I choose to pay someone to perform this test for me. This test is not required for aluminum tanks manufactured after 1988.

Edited by Dennis, 22 August 2006 - 06:53 AM.

[PerroneFord]

Yea, I can't wait to see how that contraption works.

[Dive_Girl]

I recall (an correct me if I am wrong here) isn't it likely that on subsequent hydrotestings that the tank will lose the + rating?

Almost any LP steel tank that passes hydro should be able to get the plus. There are several practical problems with actually getting the plus. Many folks doing the hydro actually believe the plus is only available at the first hydro (at the time of manufacture). Many don't know how to do the extra math (that's all it is - extra math) to give the plus. Some simply refuse to give the plus.

Walter's got it right on that one. It depends on the hydro facility.

Taking a Cylinder Safety Inspection course from PSI or Diving Technologies International is a good idea. Then you can safely and confidently inspect your own cylinders. However, to do a Vis Plus on the older aluminum tanks, you have to purchase an expensive eddy current tester. I choose to pay someone to perform this test for me. This test is not required for aluminum tanks manufactured after 1988.

I wondered about that! Thanks guys!

[Dive_Girl]

So how about the terms DIN and Yoke?

Has the makings of its own thread me thinks...

Good point! I moved it into its own thread here.