Plus ratings and hydros'

[idive2]

Yeah, I was guaranteed that he'd test for it, but he said that most did not pass. It didn't come back with a plus or a note.

I've read that you can obtain the results of your hydro from the hydro station.
In my particular case the hydro facility did not do plus ratings and came right
out and stated that, unfortunately it was after my hydro. I'm not so sure most
older 72's would qualify for a plus rating even after obtaining the REE value.
After doing some quick math there is a fair amount of difference between just
passing and qualifying for the plus rating. I would venture to guess that most
of the newer LP tanks would qualify.

 

[captain]

Actually most would qualify. I have 10 old 72's from 1957 to early 70's. My hydro shop doesn't do plus but I get the test results and all qualify for the plus. If they are doing the hydro correctly and by that I mean doing the round out procedure before the actual test I venture to say most will qualify. Are you sure you understand the math.

 

[oxyhacker]

I quite agree. From my experience, if the hydro is done right, a 72 that passes the basic hydro is much more likely to also pass the "+" than to fail it.

Actually most would qualify.

 

[idive2]

I was not aware of any round out procedure on the older LP tanks but
even if there was something that would encourage the hydro
tester to perform one it seems that many are not all that interested in the extra step
or your plus rating. I think there is a bit of a difference though between bringing in
an old 72 without an REE and bringing in a newer LP tank with an REE stamped
right on the tank. It seems with these plus hydros and round outs it's not a matter of
what they can do for you it's a matter of what they will do for you.

 

[captain]

I was not aware of any round out procedure on the older LP tanks but
even if there was something that would encourage the hydro
tester to perform one it seems that many are not all that interested in the extra step
or your plus rating. I think there is a bit of a difference though between bringing in
an old 72 without an REE and bringing in a newer LP tank with an REE stamped
right on the tank. It seems with these plus hydros and round outs it's not a matter of
what they can do for you it's a matter of what they will do for you.

Yes it is more of what what they are willing to do.
I don't much care about the + because I fill my own tanks, but I always have the hydro shop agree to do the round out procedure and give me the test results or else I go elsewhere. That way at least I know if it qualifies for the plus even if it isn't stamped with a plus.
Not doing the round out can result in a good tank failing whether it would have qualified for the plus or not.

 

[oxyhacker]

A good point. But lot of us search around for the cheapest hydro shop we can find, then expect boutique service from them, for the same low (I wouldn't do it for that!) $10 or $12 per tank that they do CO2 fire extinguishers for. And and surprisingly often we get it. On the other hand, there are some hydrotesters , usually connected with a diveshop, that specialize in scuba tanks, know all the fine points - and charge double for doing the exercise cycle, even though it only takes a couple minutes more! So the customer has a choice - find a run of the mill hydro shop, and try to educate them, or go to a shop experienced in the subtleties of scuba tanks, and probably pay a lot more. Or, if you are lucky, find one of those rare shops that combine the two. But keep in mind that hydrotesting is very much a volume business - these shops make their money from hustling fire extinguisher tanks through at a fearsome clip, not by fussing over scuba tanks, so you may have better luck getting the extras from one if you offer to pay for it.

Oh, the PST bulletins advising the exercise cycle apply to all galvanized PST tanks, HP and LP. Worthington has a similar procedure. It's pretty clear that galvanization does something to weaken the tank (or at least, make it more prone to fail hydro).

It seems with these plus hydros and round outs it's not a matter of
what they can do for you it's a matter of what they will do for you.

 

[duckbill]

Oh, the PST bulletins advising the exercise cycle apply to all galvanized PST tanks, HP and LP. Worthington has a similar procedure. It's pretty clear that galvanization does something to weaken the tank (or at least, make it more prone to fail hydro).

I doubt it weakens a cylinder, just possibly affects its roundness.

O.K. You covered:
a) dive shop related hydro stations that "know all the fine points" and usually charge more
b) fire extinguisher hydro stations that are uneducatable
c) fire extinguisher hydro stations that are educatable but charge the same low price
and, d) fire extinguisher hydro stations that are educatable for a price

However, you left one category unmentioned, and that is a dive shop related hydro station who charges more for the service and doesn't really know what he is doing.

For years, I trusted my cylinders to "the professionals" of a couple LDSs and their hydro man who specializes in scuba cylinders until he lost one of my cylinders once (found it later), and I discovered he tests for the "+" by upping the test pressure by 10%.

So, for those that think a dive shop endorsement of a hydro facility is enough to warrant your trust, don't. Always be ready to educate, and keep a watchful eye on everything. I'm still on a quest for a "professional" professional hyrotester.

 

[captain]

The shop I use is a commercial shop that does fire extinguishers, and SCBA tanks. I talked to the tech doing the hydro, gave him a copy of the roundout procedure and impressed on him that the steel 72's are long out of production and that having one fail because of not following the procedure would be like destroying a mint 57 Chevy Belair convertible because of a flat tire. I pay their regular price.