Exploding scuba tank kills two tourists (sep 24, 2010)

[Troutmaster]

This is pure speculation, however, I think it is most likely this was a dropped tank that the valve broke off, making the tank and valve both very deadly projectiles.

Thread corrosion or sustained load cracks will certainly cause a tank to fail and rupture, but those failures almost always happen when the tank is being filled.

If any of the story is true, then "unloading" tanks would seem probable someone dropped a tank. This would not be the first death caused by that set of circumstances.

 

[stairman]

I agree the tank was probably dropped and broke off the valve. Unless it was o2, it wouldnt have exploded per say but things flying thru the air at high speeds might be categorized as an explosion by someone else. In any event it is sad.

 

[scubatocuba]

I use to make these tanks and test them, at 'Catalina Cylinders"material is #6061 and 1/2 in thick.....But we do get always on occasion bad material , as stock can have bad mix with the aluminum..from the foundry.....So then you get hair line cracks that are over looked when inspected. 3000lbs/+ of air just lets her pop like a balloon.So yes occasionally, one dose get a bad valve that's falty. That has nothing to do with the tank ripping wide open as it is experiencing bad materal from the foundry that the batch of Aluminum was made. {{{Just for example,making a bad batch of cookies.}}} No way of telling,when a tank is going to blow up...The threads are another problem ..But I won't get into that part just yet...You just have to treat a Scuba TANK like a baby...Take good care of it,..and it will take care of you...

 

[scubatocuba]

The trouble we would face was not a bad valve. But bad materal from the foundry.
Some tanks would show no sign of hair line cracks inside of walls of cylinder,and some did show slight cracks.Yet the tank would still pass visual scope camera inspection. I guess after testing under pressure of 3000/+psi....If it didn't blow up under water in the safety tank it passed...In all.....For all practical reasons...
But when a tank explodes,out in the field of sport diving,The first thing that the media comes to blame is a bad valve....
yep not a tank that had bad materal to begin with from the manufacture.
That might put ,LUXFER,SHERWOOD,&CATALINA CYLINDERS out of business.....

 

[SC_Hoaty]

Is it known if this is a steel or aluminum cylinder?

 

[SC_Hoaty]

The trouble we would face was not a bad valve. But bad materal from the foundry.
....
That might put ,LUXFER,SHERWOOD,&CATALINA CYLINDERS out of business.....

Sounds like independent testing of each heat from the foundry might be a wise move to ensure alloy composition.

 

[DevonDiver]

Unless it was o2, it wouldnt have exploded per say but things flying thru the air at high speeds might be categorized as an explosion by someone else.

You're only thinking of chemical explosion, through combustion leading to rapid gas expansion. Explosions can also result from mechanical, nuclear and kinetic (gas under pressure) effects.

explosion (ĭk-splō'zhən)
A violent blowing apart or bursting caused by energy released from a very fast chemical reaction, a nuclear reaction, or the escape of gases under pressure.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.

 

[Thalassamania]

I agree the tank was probably dropped and broke off the valve. Unless it was o2, it wouldnt have exploded per say but things flying thru the air at high speeds might be categorized as an explosion by someone else. In any event it is sad.

Oxygen does not explode.

 

[scubatocuba]

OK, Now lets talk about threads at the neck of the tank...Are they torn out from testing to many times. Are the threads torn out and poorly made in the first place? Was the thread made with a form threader, or single point threader on a CNC? Some threads just suck as with carelessness from the machining process..CNC programed to run fast,for more production of tanks."Quanity" not "Quality" in a lot of American made products....It's all about makeing $$$money in this "WORLD"$$$

 

[stas]

A flaw in the cylinder and/or valve, leading to a rupture and catastrophic loss of pressure. A 3000psi cylinder contains an enormous amount of kinetic energy.

An average scuba tank, filled to 3000psi, contains approximately 1.3 million foot-pounds of kinetic energy potential. This is enough to lift a 100-ton locomotive off its tracks and into the air.
The explosive power of a scuba tank is equivalent to a hand grenade.

Link: Scuba Tank Safety (what happened when a tank exploded in a car)

Disregarding the motion of the gas particles (microscopic scale), a tank at rest has zero kinetic energy but a lot of potential energy