Tank Life Span

[ScubaBeez]

Is there a limit to the number of times a tank can be Hydro'd?
I have a set of tanks that look (to me) like they are in pristene condition with shiney clean almost new valves. They just happen to have quite a few hydro stickers on them and another novice mentioned that they may not be good for much longer seeing as they can only have a certain number of inspections.
This sounds rediculous to me as long as they pass all inspections, but what do I know...

 

[Cheekymonkey]

Steel tanks will last indefinently if they are well taken care of. Aluminums can last a long time too, but are generally not as long as steels, although if they are not from the bad alloy then you shouldnt have any problems with them.
I don't think there is a limit to inspecitons, i've been told that there are tanks from the 1900-1910 years that are still in service.

 

[OceanSailor]

In the U.S. five hydros (after the initial hydro when manufactured) used to be the limit for pressure vessels (tanks) subjected to cycles of charge/discharge. As far as I know, this limitation on the number of hydros applied only in the States. Contact any dealer in gases and they should have the latest info.

Cap'n Ed

 

[spectrum]

Stickers would imply VIP inspections which are done yearly and should include removal of the prior sticker.

Hydrostatic testing which is required every 5 years involves stamping into the crown of the cylinder with steel dies.

I know of no time or cycle limit for either procedure on steel cylinders.

What sort of cylinders are they? If they happen to be low pressure 2400 PSI cylinders you will want to make it a point to have the tester attempt to certify them for the + rating which lets you go up 10% to 2640 PSI which is actually the advertized capacity.

Pete

Is there a limit to the number of times a tank can be Hydro'd?
I have a set of tanks that look (to me) like they are in pristene condition with shiney clean almost new valves. They just happen to have quite a few hydro stickers on them and another novice mentioned that they may not be good for much longer seeing as they can only have a certain number of inspections.
This sounds rediculous to me as long as they pass all inspections, but what do I know...

 

[captndale]

I have several tanks still in service that were made in the 60's and early 70's. I seem to remember seeing some information once that claimed that 2400 psi Faber tanks had an expected life of 40,000 pressure cycles at a fill pressure of 2640 psi or 10,000 cycles at 3500 psi. I doubt that anyone would put 10,000 cycles on a single tank in a lifetime. If a tank got filled and used every day it would take over 27 years to put that many cycles on it.

 

[Gary D.]

In the U.S. five hydros (after the initial hydro when manufactured) used to be the limit for pressure vessels (tanks) subjected to cycles of charge/discharge. As far as I know, this limitation on the number of hydros applied only in the States. Contact any dealer in gases and they should have the latest info.

Cap'n Ed

Where did you hear that one at? I've got tanks from the 50's that are still kicking away. I just heard that the last of the original Navy aluminum 90's were taken out of service last year. That's a lot of cycles in almost 50 years and that would be way more than 5 hydro's.

Gary D.

 

[chrispete]

i've been told that there are tanks from the 1900-1910 years that are still in service.

I've personally seen some steel tanks in a cascade dated around this time, so they do exist.

Chris

 

[rookers]

1948 is the oldest steel I have seen. 1982 for aluminum, though I know there are older ones out there.

 

[String]

Got steel tanks here > 15 years old. The club did own 1 aluminium tank 8 years old but that got condemned and destroyed.

 

[Jimmer]

I have 2 sets of doubles, my "new" set turned 10 years old this year, my old set turned 34 (I'm only 25 lol) years old this year with original hydros of Jan. 1973. I was filling steel 72's to use in the pool with students a couple weeks back, and checking my instructor's 72's for fun, and found one from 1961, and about a half dozen from before 1970. Take care of them and tanks last a long time.