O2 tank explosion

[ZenDiver.3D]

Doh! Seems my chemistry professor was a crack pot! Or maybe I just misremembered? Probably the latter. Either way, in a highly oxygenized (is that a word) environment, fires get bigger faster.

Oxygen does not explode, it is an ignitor. It will heat any carbon fast enough and then feed any resulting spark or flame to make for what we see as ,"an explosion." It is violent and then continues to feed flames.

My commercial guy had to make a csa from 22 meters adn immediately went, cranked open our O2, instead of gently gently, and it took just a second to burn a hole in a gear bag against the valve and we lauched the tank over the side before it could truly dump out more O2. It goes up very quickly.

There is also the possibility that the valve rotated on impact and the friction in the threads caused ignition of metal dust and/or lubricant. There is one reported and investigated case where someone tried to tighten the valve of a filled O₂ cylinder with explosive results.

OSHA requires compressed gas cylinders to be secured for a reason. Even without an explosion, a full cylinder with a broken-off valve becomes a missile that fully penetrates a cinder block wall - as shown in mythbusters.

Have you ever tipped a tank and the valve crack open a twist against the ground or whatever it falls against? Air flows. O2 tanks doing that can cause exactly what seems to have happened here. There doesn't have to have the valve break, just open a bit.

OW students are taught to not stand their unattended tanks up because if they fall over the tank could crack the tile on the pool which means the LDS would have to pay for the repair. Plus it is supposed to get the student in the boat dive mindset where a standing, loose tank is never a good thing.

I have yet to see an LDS that stores their tanks other than standing and loose. It is a standard practice because tanks are not eggs.

Yup. All of mine are standing up. But not my O2 tanks. We have our big blending tanks chained to the walls and then our emergency boat tanks are laid down in a crated in corner. We have seen a bottle open too quickly. We learned this already. I am very sorry this had to happen to them, but they don't have to have a "fault" for this. It was a terrible accident. I don't find blame, myself, here. Nothing more. An accident....

 

[Rythmmaker]

Ed,
Glad you are there and can pitch in. Both Cindy and Rick will need much assistance as the dust clears. Personally, I feel a bit helpless to do much from 3,000 miles away in San Diego but one couldn't find nicer folk than Rick and Cindy.
Steve

A friend of Rick and Cindy has set up a blog where you can find more information and offer both moral and financial support.

Rick lost a hand and part of his arm as a result of the accident and they need all the support they can find:

Get Well Rick

Thanks!

 

[BDSC]

Cindy e-mailed my wife (Kim) this morning so Kim is going to be spending some time with them next week helping out in any way she can. If it's OK with Rick and Cindy, maybe I'll be able to post something next week and give an update on his condition.

 

[cruiser]

Yup. All of mine are standing up. But not my O2 tanks. We have our big blending tanks chained to the walls and then our emergency boat tanks are laid down in a crated in corner. We have seen a bottle open too quickly. We learned this already. I am very sorry this had to happen to them, but they don't have to have a "fault" for this. It was a terrible accident. I don't find blame, myself, here. Nothing more. An accident....

Has this already been determined this early in the investigation?

 

[ScubaVideo]

Originally Posted by ZenDiver.3D View Post
Yup. All of mine are standing up. But not my O2 tanks. We have our big blending tanks chained to the walls and then our emergency boat tanks are laid down in a crated in corner. We have seen a bottle open too quickly. We learned this already. I am very sorry this had to happen to them, but they don't have to have a "fault" for this. It was a terrible accident. I don't find blame, myself, here. Nothing more. An accident....

Has this already been determined this early in the investigation?

You mean VS an intentional act? There is certainly no determination of what caused this accident, but unless it was a bomb or other such device, I think we can assume it was a "terrible accident".

 

[ZenDiver.3D]

Has this already been determined this early in the investigation?

I don't know, I am late to the thread. I'll back out for you.

You mean VS an intentional act? There is certainly no determination of what caused this accident, but unless it was a bomb or other such device, I think we can assume it was a "terrible accident".

With the seeming question of could it have a faulty tank and conjecture of how it could have "exploded," I simply stated my opinion. We tend to try to find a blame for things that happen. Usually when a catastrophic accident occurs, people look for specific reasons. There were still questions about how. Sometimes things just happen. Pardon me. Carry on.

 

[charlesml3]

I would imagine that if that valve bent and allowed O2 to squeeze past the threads, it would have been fast enough to actually ignite the metal in that area, as soon as it was ignited, it would have spread inside the cylinder causing an immediate, huge increase in pressure...

When an expanding gas escapes through a small opening, it gets cold. Not hot.

-Charles

 

[fdog]

Prayers go out to this couple.

The manufacture date, if I'm making it out correctly, is 4/88 which depending on the manufacturer and size could mean it is indeed a 6351 AL alloy. See http://www.scubaboard.com/forums/tanks-valves-bands/346966-my-cylinder-made-bad-alloy-aka-al6351.html

I froze the vid and took a screen picture. Perhaps someone with better eyes and more knowledge about al tanks can examine this and add comments; but I think I see is a damaged valve and tank neck interface, a blown o-ring, and some charred substance around the DIN port-perhaps a plastic dust cover that became fuel for the fire.

Couv

When I saw this image, I was immediately reminded of several images as seen in this YouTube video:




The video has about 20 seconds of black screen, in the beginning, as the incident is narrated. (Obviously) the causes are different, but some similarities may be drawn. Perhaps SLC was a cause? I will re-think many of the common practices we use with our deco bottles.


All the best, James

 

[mitsuguy]

When an expanding gas escapes through a small opening, it gets cold. Not hot.

-Charles

actually, it gets hot first, then cold... it gets hot when it enters the small opening at a high rate of speed - lots of gas compressed into a small area... this causes two things actually, particle impingement and heat... once it has made it past the small opening, then it cools back down to the part of being cold... its not the escaping I'm worried or talking about, its the high amounts of O2 being compressed and pushed through the tiny areas (around the threads of the valve) at high rates of speed...

 

[05sportsman]

When I saw this image, I was immediately reminded of several images as seen in this YouTube video:




The video has about 20 seconds of black screen, in the beginning, as the incident is narrated. (Obviously) the causes are different, but some similarities may be drawn. Perhaps SLC was a cause? I will re-think many of the common practices we use with our deco bottles.


All the best, James

I don't think so, If you look at the videos the tank did not split at the neck/bottom of threads. This is where the sustained load cracks reside. I have never seen a picture or heard of a tank where it exploded from SLC and didn't split at the threads.