Scuba tank explosion - man loses hand

[Cave Diver]

I am sorry I don't get the maths.. how can a 20 year old tank have 100 years of hydro test stamps? yes the stamps are quite small.

Here, hydro testing is required every 5 years. If y'all test tanks every year, that's 5 times more often, so over the course of 20 years it would be the equivalent of a 100 year old tank in the US.

 

[bowlofpetunias]

Hmm... interesting I find it even more interesting that oxygen tanks in OZ don't have to be tested as often as scuba tanks!

 

[DA Aquamaster]

To some extent it makes sense to test/inspect O2 tanks less than scuba tanks as they are generally lower pressure tanks in the 2000-2200 psi range and due to the nature of their use they are not as likely to be exposed to water in amanner that might result in moisture inside the tank. The same argument can be made for CO2 tanks.

 

[Doc Harry]

Does anyone know if there's ever been a catastrophic failure of a 6061 tank?

The manufacturers induce catastrophic failures of their cylinders during the R&D phase of cylinder manufacturing. There have been probably dozens of intentional catastrophic failures of 6061 cylinders.

But accidental catastrophic failures of 6061 cylinders? Not in the USA that I have been able to find.

All catastrophic failures of 3AL cylinders (at least in the USA) were 6351s that failed from sustained-load cracking -- except one.

One 6351 cylinder had some slag accidentally incorporated into the cylinder wall during the forming process, creating a weak spot. It explosively failed at 3,200 psi during a fill.

 

[Web Monkey]

Does anybody know if AU requires an eddy current test on AL tanks?

Terry

 

[String]

A test only certifies that a tank meets the required standard *at that point in time*. They have no way of determining the health of a tank after that - it could be heated, dropped, banged and so on so although they serve to weed out tanks that are slowly failing they cant gurantee a tank in test is safe to fill or use. Oxygen cleaning is exactly the same.

In the UK tank testing is every 5 years for hydro and 2.5 years for visual (so 2.5 yearly increments for some sort of test). This is far far more thorough than tanks such as fire BA systems, industrial bottles and so on all of which have FAR more empty/fill cycles than scuba.

Aluminium tanks require extra eddy testing and neck thread testing which isnt required for steel (although nobody in their right mind would use aluminium tanks for a main tank anyway.

In Egypt testing is 6 monthly which is laugable and will reduce the tank life somewhat.

 

[MauiScubaSteve]

although nobody in their right mind would use aluminium tanks for a main tank anyway.

As usual; nearly entertaining, completely ignorant!

 

[String]

As usual; nearly entertaining, completely ignorant!

As usual from that i can only infer you have no real experience diving anywher except your local area. Not everywhere in the world dives positively buoyant tanks that require more lead on the belt to sink and hold less gas at a lower pressure and weigh more than steel equivalents

 

[davros]

Does anybody know if AU requires an eddy current test on AL tanks?

Terry

Yes Terry, it is required for cylinders made from 6351.

One of mine failed that test the other day. It was my last tank made from 6351. really, I am glad to see it go. The three I have left now are 6061 from 1996, and they all passed hydro without fault.

 

[Web Monkey]

Yes Terry, it is required for cylinders made from 6351.

One of mine failed that test the other day. It was my last tank made from 6351. really, I am glad to see it go. The three I have left now are 6061 from 1996, and they all passed hydro without fault.

Thanks, just curious.

Our shop does an Eddy Current test before the VIP on any aluminum tank, regardless of age or alloy, so all the tanks we fill get inspected every year.

Not sure if it's shop policy, DOT or something else, but we always test them.

Terry