Tank PSI - Over Filled, Drain or Dive?

[The Chairman]

Can anyone give me an example when a tank ruptured "while a diver was wearing it"?

http://www.scubaboard.com/forums/ac...0-exploding-scuba-tank-kills-one-florida.html : He was carrying to his car. Does that count?

 

[chrpai]

http://www.scubaboard.com/forums/ac...0-exploding-scuba-tank-kills-one-florida.html : He was carrying to his car. Does that count?

Probably not. Was the final determination ever made? A scan of that thread made it sound likely that it was an AL40 full of 100 O2 and possibly a non-O2 clean reg attached to it. That's not really a fill pressure problem.

 

[The Chairman]

The law suit is still progressing so there is a tight lid on the whole thing. However, my sources close to the investigation indicate that the problem was the overly high pressure in the tank. It's obvious that some think rules are meant to be broken or at least bent. I know that I am not immune to that and often allow a "cave fill" on my tanks. Tanks are designed to expand and contract on every fill. Over filling them causes them to expand beyond their elastic design limit and enter the plastic zone. That's a permanent deformation and results in the work hardening of the material. Steel seems to be more forgiving of this than aluminum, but it's also more susceptible to corrosion. In the end, we are going to have our tanks filled in a way that suits our needs. Except for a few instances, I prefer my tanks to be within 10% of their fill capacity (high or low). But then, I am a fairly cautious diver that tries to learn from the mistakes of others.

 

[chrpai]

So it wasn't an O2 AL40? If it it was, I can't say I've ever heard of someone overfilling that. I can think of three reasons why you wouldn't.

 

[The Chairman]

So it wasn't an O2 AL40? If it it was, I can't say I've ever heard of someone overfilling that. I can think of three reasons why you wouldn't.

You're probably thinking of the accident in Austin, and I can't speak about that at all. While I wasn't present at the explosion but I was staying at his house when it happened. I understand that there is at least one law suit pending in that one. There are quite a number of hypothesis concerning that incident that have not made it onto ScubaBoard.

 

[chrpai]

No, in your lined thread the linked articles and comments it seemed that people were saying he was a tech diver and that it was an AL40 with O2 and that there was a flash associated with the explosion. There was updates saying they went back to look for the missing regulator and that they found it.

Well, if no one can talk about it then no, it doesn't count.

 

[cbrich]

You're probably thinking of the accident in Austin, and I can't speak about that at all. While I wasn't present at the explosion but I was staying at his house when it happened. I understand that there is at least one law suit pending in that one. There are quite a number of hypothesis concerning that incident that have not made it onto ScubaBoard.

This is topic, that should be treaded lightly too, as the person in involved is a dear friend to a lot of us. His road to recovery has been painful as is, and he don''t need folks make speculations about what happened.

 

[Tortuga68]

Well if you dive it, you'll probably be lowering the temp/pressure, and draining it at the same time

 

[nimoh]

Well if you dive it, you'll probably be lowering the temp/pressure, and draining it at the same time

I've had dives where my pressure went up once in the water. Leaving the -20F surface for the nice warm 35F water has that effect on a tank

 

[maniago]

True, there is nothing more for you to say. You've got a lot more reading to do before. You might want to consider that Luxfer tanks are burst tested to 2.5x the service pressure. That's 7500 PSI. The DOT test pressure is 5000 PSI and they are cycle tested at service pressure 100,000 times.

Would I get in the habit of over filling an AL80 to 3800? No. Does it happen from time to time? Yes. It it a recipe for instant death? Typically not. Will it shorten the life of the tank? Some. Hydro every 5, inspection annually is enough to make the odds really really good that you'll be fine.

Seriously, step it down a notch Hoss. I never said it was instant death any more than you want to make it 100% safe. I said I would have it bled down and I gave my reasons for what I would do. Note the "I" in the sentence. That applies to me. I didn't say the OP had to or that you have to. Chill out.