Heating a tank up

[jonnythan]

roakey once bubbled...
(you DID of course get a signed release from the customer before hand stating that their cylinder could be condemned and rendered unusable, didn’t you?)

Assume this was me. I've never signed anything at all when bringing in a tank for a fill. Does my LDS have the authority to destroy my tank if they deem it unfit for continued use? I'm not sure how i feel about that, but is it true?

 

[cmay]

you can also make a pretty cool set of lamps out of condemmed tanks. makes an interesting conversation piece in your living room.

 

[Rick Murchison]

jonnythan once bubbled...
Assume this was me. I've never signed anything at all when bringing in a tank for a fill. Does my LDS have the authority to destroy my tank if they deem it unfit for continued use? I'm not sure how i feel about that, but is it true?

This falls into the general area of public safety... the shop is acting as an agent of the government in this case - if you decline to have them destroy the tank markings, they would be perfectly within their rights - and duty - to notify the DOT of the situation, who'd then enlist whatever federal law enforcement was needed to enforce the law. You may be subject to fines.
Consider, for a moment, the nature of a bursting high pressure tank - to allow a tank that should be condemned back out into the general population, especially if the tank owner objects to the condemnation, would be dangerous and irresponsible.
You don't necessarily have to XXX out the markings, though. If you really want to keep 'em for show, you can cut the bottom off the tank. IOW you either have to make it obvious the tank shouldn't be filled again, or make filling impossible.
Rick

 

[FredT]

jonnythan once bubbled...


Assume this was me. I've never signed anything at all when bringing in a tank for a fill. Does my LDS have the authority to destroy my tank if they deem it unfit for continued use? I'm not sure how i feel about that, but is it true?

The shop has the authority to destroy a vis failed tank, but I tend to get annoyed with those that do before I see it. When dropping off a tank for service be VERY specific about procedures for "failed" hardware up front.

I get particularly annoyed with hydro shops that X out perfectly good expensive HP tanks because their setup or procedures were faulty. A "failed" hydro doesn't necessarily mean a failed tank. Internal leakage on the fittings used to perform the hydro can give a false fail. Unless the setup was broken down completely and checked for leaks or worn o-rings a retest is meaningless. The natural method is just re-run the test without doing the breakdown, which simply proves the failure mode is consistant, not what it is.

PST has a "rounding" procedure that is necessary for reliably testing their tanks, that is not always followed by hydo facilites. That procedure was available on the PST website when I checked for it a while back. If taking PST tanks in I suggest you get a copy and affix it to the tank! I know of one case where two "new" HP 120s were failed on the first hydro test because the hydro shop didn't do the required rounding procedure. Those tanks passed a subsequent hydro with essentially nominal numbers where the rounding was properly done (something about a lawsuit as to who paid for the replacement tanks) but because the DOT stamp was Xed out the tanks had to stay dead.

If a steel tank fails hydro from two facilites it's an incipient gong. A simple "close" fail from a single facility is not enough to determine if the tank is dead. It simply means the facility or tank has a problem and the tank should be pulled from service until the culprit is identified. Retest at a different facility will determine which is at fault. I have 3 tanks that once "failed" hydro back in the 80s, and have now passed 4 subsequent hydros at different facilities over the years. Having now identified a "bad" hydro shop I stopped doing business with them. Hydro testing is not rocket science, but it does require attention to details. A shop that shows less than the required QC internally should not be performng QC for others.

A failed vis for pitting or deformation on the other hand kills the tank immediatly. ANY indication of extreme heat applied to ANY part of the tank, be it Aluminum or Steel, kills the tank by DOT regs. Aluminum tanks very rarely fail hydro, but regularly fail the vis mandatory before hydro. The preferred method for "killing " a vis failed tank is to destroy the valve thread and o-ring seat.

FT

 

[madmole]

In the UK, they are begining not to return failed tanks. They used to drill holes in them, but some dumb people welded them up again!!!!!!!

 

[cmay]

At the shop I used to work at, we would sit down with the customer and explain and show exactly why we were failing the tank. In the three years I worked there, we never had anyone object to having their tanks taken out of service. Don't get me wrong, none were happy, but they understood why we were taking their cylinder out of service. As for hydros, be careful. I recently had a bad experience with a hydro facility with two PST HP 100's. I had not been aware (neither had they) about the "rounding out" procedure required to get an accurate test on tanks with PST's hot dip galvanized coating. It was on this board that I found out about the technical bullitins on PST's website. Basically, the facility failed my tanks but I argued, and did my homework. I even called and talked to an engineer at PST. Even he said that he could not guess how many good PST cylinders had been taken out of service from "failing" hydros. It pays to do your homework!

I guess the moral to my story is to ask questions. A VIP tech. should be more than happy to drop a light in a tank to show you exactly why he is failing it. They should clearly explain, "these are the standards, this is why this tank does not meet these standards". With a hydro, most places will do more than one test if it fails. If you still are not convinced, take it somewhere else for a second opinion. You also need to consider the history of the tank in question. In regard to my tanks above, I had "babied" them since I had bought them. No overfills, and they had not been used much in the past few years. That was why I had such a hard time believing that they failed.

Anyway, just my $.02