Steel tank lifespan

[NAM001]

If hydro is all about DOT testing for transportation, do bank bottles get hydro tests?

yes but at perhaps a different schedule. i KNOW a shop that has perhaps a 40-50 tank bank and it gets hydro'd per schedule and he changes valves at that time on the tanks.

Just my opinion but I would think that if the tank could be transported it would be covered as a vessel that would be transferable.

 

[rjack321]

it depends on the bottles i have seen some that have a 10 yeaR CYCLE AND OTHERS THAT HAVE THE SAME 5 YEAR. AND OTHERS I THINK THAT HAVE NO REQUIREMENT INDICATED ON THEM.

DOT cylinders with a star rating (10yr hydro cycles) aren't eligible for the full 10 years unless the are removed from the bank for filling. But most banks are not hydroed regularly either way anyway.

Hydro requirements are specified in the CFRs not on the cylinders.

 

[NAM001]

DOT cylinders with a star rating (10yr hydro cycles) aren't eligible for the full 10 years unless the are removed from the bank for filling. But most banks are not hydroed regularly either way anyway.

Hydro requirements are specified in the CFRs not on the cylinders.

yes your comment is what I have observed. did not know about the star rating thing other than the star was a 10 year interval. The ones I saw wtih the star were 4500 psi tanks. probably 1 inch thick who knows.

 

[rjgiddings]

I would hydro those suckers every five years until they didn't pass. I've seen cylinders from the 1960's still in use.

 

[2airishuman]

If hydro is all about DOT testing for transportation, do bank bottles get hydro tests?

It varies from state to state and depends on the dive shop.

In Minnesota, there are inspection and insurance requirements for high-pressure containers. There is an exemption for DOT cylinders used in compliance with DOT regulations. It is cheaper and less burdensome to comply with the DOT regulations than it is to get the inspection certificate every year.

 

[2airishuman]

If it is a dive shop, it would be prudent to have them tested. The pic attached was from a dive shop bank!! If it your bank, who is to know and if they are not being filled and offer for transport the CFR doesn't apply. But lawyers being lawyers....
View attachment 595660

Do you have a source for that? It appears to me that a good deal of the thread corrosion had to have occurred after the valve was removed.

 

[Aqua-Andy]

1908 is impressive!

I've heard there are still welding bottles in service that were manufactured in Germany during WWII and stamped with swastikas. Never actually seen one though. Apparently they're often crossed out to make a sort of "Windows logo".

I have seen one of these cylinders, it definitely looked like the lines were added to make the four pane window stamp. Whether this is just an old tale I don't know but the hydro dates are in the range so who knows? It does make for some good stories though. I always check cylinders for old dates when they come into work, It's fun to think where these things have been. The oldest I have come across is 1908. I have three 72's that I use and the youngest is from 1974.

 

[bletso]

Do you have a source for that? It appears to me that a good deal of the thread corrosion had to have occurred after the valve was removed.

Source is myself. We took in their cylinders, and condemned 3 of 5 due to severe thread corrosion. I run a hydro facility. BTW, that type of corrosion I have seen from time to time although this was the worst I have seen.

Here are a few other things we have seen. hydro reasons

The CFR's as regards cylinders is found in CFR 49 Part 180.205/209 Happy reading
Electronic Code of Federal Regulations (eCFR)
Electronic Code of Federal Regulations (eCFR)

 

[drbill]

Out here I've never had a lot of luck with steel tanks due to hot fills on land and wet fills on dive boats. These were PST HP120s and none lasted past the second hydro. I dive neutral buoyancy Al80s now and the shop says they look as clean inside as the day they came off the showroom floor back in the 70s.

 

[rjack321]

Source is myself. We took in their cylinders, and condemned 3 of 5 due to severe thread corrosion. I run a hydro facility. BTW, that type of corrosion I have seen from time to time although this was the worst I have seen.

Here are a few other things we have seen. hydro reasons

The CFR's as regards cylinders is found in CFR 49 Part 180.205/209 Happy reading
Electronic Code of Federal Regulations (eCFR)
Electronic Code of Federal Regulations (eCFR)

some of those holes look drilled??