Maximum test pressure

[oxyhacker]

I was curious because I have never yet found a hydrotester who was willing do the "+' on steel 72s, who did it correctly!

That's not to say there aren't any. I'm sure there are some long-established hydrotest shops that have the holy grail of scuba hydrotesting, a battered old file or notebook containing the REE's for old 72s. And the reemergence recently of the REE for the PST 72s means that now it can be done for PST tanks at least by any hydroshop willing to make the effort. But that said, of the half-dozen or so hydro shops that have "+" -tested 72s for me over the years, or offered to do so, all of them turned out to be using some botched method other the only official one, the one given in CFR 170.302a(b), Usually by just doing the standard test at a 10% higher test pressure.

So the joke is, that by choosing a hydrotester on the basis of whether or not they can do the "+" on old 72s, without a thorough quizzing to establish that the shop does indeed know how to do it, all one is likely to accomplish is insure that one finds a hydrotester doesn't know what they are doing.

Well, both.

Our only LDS uses the guy, even though he is 40 miles or so away.

I know at least one dive shop in Sacramento that uses him too, and I'm sure there are others as well.

He is also the only hydrotester in this general area that I know of who offers the "+" rating, and that is (read "was") my biggest determining factor considering there are other hydrotesters nearby.

 

[Couv]

....that have the holy grail of scuba hydrotesting, a battered old file or notebook containing the REE's for old 72s. And the reemergence recently of the REE for the PST 72s means that now it can be done for PST tanks at least by any hydroshop willing to make the effort. But that said, of the half-dozen or so hydro shops that have "+" -tested 72s for me over the years, or offered to do so, all of them turned out to be using some botched method other the only official one, the one given in CFR 170.302a(b), Usually by just doing the standard test at a 10% higher test pressure.

.

Vance,

"Ignorance is Bliss"

But now that you have brought this to light, what would be the harm, if any, if one were to find the REE number and have it stamped on to the tank? Surely, someone is authorized to make such a stamping. Are there any stamping restrictions other than altering official markings on a tank?

Couv

 

[oxyhacker]

I actually asked someone at the DOT this question once, and they said only the tank manufacturer is authorized to stamp markings on the tank (other than the ones the hydroshop is authorized to do).

If you mean why not just do it surreptitiously, for convenience at the next hydro, the problem is, the practice of stamping REEs on the tank wasn't authorized until fairly recently, and was never done in the days of the 72, so if some picky fill monkey or inspector happened to notice it they might refuse to fill the tank, or even condemn it.

Stamping things on tanks seems to be a bit of a gray area as some fleet users stamp their name on tanks. But since the REE is an "official" marking, like the pressure rating or DOT spec, faking it would almost certainly be grounds for condemnation.

Vance,

"Ignorance is Bliss"

But now that you have brought this to light, what would be the harm, if any, if one were to find the REE number and have it stamped on to the tank? Surely, someone is authorized to make such a stamping. Are there any stamping restrictions other than altering official markings on a tank?

Couv

 

[DA Aquamaster]

There was a butterbar in charge of the base recreation program who was concenred about the possibility of scuba tanks being stolen, so he stamped the the unit number and USAF in the sidewall of all the tanks. Ignorance was indeed bliss - until he discovered the damaged tanks all had to be condemned.

 

[Couv]

Well....they didn't get stolen; did they?

Butterbar...I haven't heard that one in a long time.

c

 

[duckbill]

I was curious because I have never yet found a hydrotester who was willing do the "+' on steel 72s, who did it correctly!

That's not to say there aren't any...............So the joke is, that by choosing a hydrotester on the basis of whether or not they can do the "+" on old 72s, without a thorough quizzing to establish that the shop does indeed know how to do it, all one is likely to accomplish is insure that one finds a hydrotester doesn't know what they are doing.

That's what I get for assuming a professional knows what he is doing. The more business I do with others and the more I learn, the more I have come to realize how many "professionals" don't have a clue! It's really getting frustrating.

But then to have to quiz the "professional"? I was always told not to tell someone how to do their job. LOL! I guess it's time to quiz some hydrostatic retesters.

 

[oxyhacker]

Hydrotesting is a funny business. You got a few boutique operations that specialize in scuba tanks, and are very knowledgeable, but then you got others that just do zillions of CO2 fire extinguisher or med O2 bottles day after day, charging a lot less to do them than you or I would. Since the latter kind are much cheaper, divers tend to take their tanks to them, then wonder why the shop doesn't seem more on top of things. When you come it with a scuba tank they are often very happy to try and help you out, but it's sort of like when you pull into the Ford dealership in some tiny town in New Mexico and want them to take a look a the carburetors on your Porsche. They can do the basic hydro just fine, but have only a foggy memory of what an exemption tank is, and haven't done a "+" in years.

A lot of them have been going by rote for the last decade or so, and the operator may not even had had any training other than the previous guy explaining to him how to do it. A hydrotest facility is required to have on hand hard copies of the applicable CGA publications, and CFR Title 49, but many of them haven't opened either in years
and are afraid what they might find if they do.

So if you really want them to do the PST "exercise" cycle, or "+" rate your tank, it only makes sense to make sure they know how to do it. even if it may seem a bit pushy. Just like when you go see the doctor who is going to remove some major part of your body!

That's what I get for assuming a professional knows what he is doing. The more business I do with others and the more I learn, the more I have come to realize how many "professionals" don't have a clue! It's really getting frustrating.

But then to have to quiz the "professional"? I was always told not to tell someone how to do their job. LOL! I guess it's time to quiz some hydrostatic retesters.

 

[duckbill]

So if you really want them to do the PST "exercise" cycle, or "+" rate your tank, it only makes sense to make sure they know how to do it. even if it may seem a bit pushy. Just like when you go see the doctor who is going to remove some major part of your body!

Is the PST "exercise" cycle the rounding out procedure (80-90% pre-test)?

 

[rjack321]

Is the PST "exercise" cycle the rounding out procedure (80-90% pre-test)?

Yes, also known as a "prestretch" which miraculously allows their actual test expansion to not be proportionally as large.

Funny thing about the 10% over TP for your vintage 3AA tanks... I know quite a few divers doing something close to TP for every dive (3600psi fills into 2400+ tanks which are only tested at 4000psi anyway). I wouldn't pursue additional testing on those tanks until their next hydro cycle.