Exploding scuba tank kills one - Florida

[flots am]

Just looking at the pictures on the local news, this was an explosion, not a shrapnel issue.

The explosion blew out windows and a door, and damaged cars in the parking lot. Blew out all or most all of the glass in the windows.

It indicates to me the explosion occurred inside the condo.

I don't know anything about tanks bursting, but this was an explosion based upon the pictures.

Nothing like the discussion of a tank bursting or the pictures shown here.

My gut tells me something else occurred with it or the tank held somethign else.

Tanks can definitely explode. There are some pretty cool pictures around SB somewhere, of a dive shop that lost a corner of the building because of a tank explosion.

That said, I've never heard of a tank exploding when it was within hydro & VIP, had an recent eddy current check, was clean and had the right burst disk.

We'll probably never know the actual cause, although I have no doubt at all that there was a cause. To the best of my knowledge, properly inspected and maintained tanks have never spontaneously exploded.

 

[Notso_Ken]

Without pulling out the actual disk, the shop cannot tell if you've got the right one in there or not, the disk is just a small insert in the nut screwed into the valve. I've replaced a few in the past couple years.

And, there is no reason doubled disks would be any more "kosher" on steel tanks than aluminium! On either one they are circumventing a safety meaqsure!


ken

Double disks are only kosher on steel tanks. Typically shops will refuse to fill an aluminum tank without the proper burst disk.

I guess then it also becomes important to know if it was a side mount diver.

Tobin brings up a good point. Are burst disks of various burst pressures made with identical threads for other gas uses such as industrial tanks? We use a different valve thread count for high pressure tanks, but the same threading and count for all burst disks...

 

[Epinephelus]

... Are burst disks of various burst pressures made with identical threads for other gas uses such as industrial tanks? We use a different valve thread count for high pressure tanks, but the same threading and count for all burst disks...

Burst disks don't have threads. They are small, flat, thin copper disks. They are often sold pre-mounted to the hollow bolt that secures them, hence the possible confusion.

Were I to make a bet... here we have a diver who's just getting into caving, and enthusiastic about it. I'd bet the tank was "cave filled" and had doubled burst disks. As someone has mentioned, there are thousands of these tanks in garages all over cave country. In my opinion they're all playing a dangerous game; my only surprise is that we don't see more of these failures, especially as a "cave fill" has crept higher and higher even as the LP steels being filled are getting older and older. When I first started caving, about 3300 on a 2400 (2640) psi tank was considered a "full cave fill." That has crept up to around 4000 psi now. It's time to back off a bit.
E

 

[Tom Smedley]

Just an oops!!

 

[FWADIVER]

wow, another excuse for people to bash on cave fills..assuming the tank passes muster overfilling lp steels isint going to do anything but shorten its life.

 

[MarineResearch]

Without pulling out the actual disk, the shop cannot tell if you've got the right one in there or not, the disk is just a small insert in the nut screwed into the valve. I've replaced a few in the past couple years.

And, there is no reason doubled disks would be any more "kosher" on steel tanks than aluminium! On either one they are circumventing a safety meaqsure!


ken

Not necessarily circumventing a safety measure, but reducing the margin of safety related to tank over-pressurization and failure, which is extremely rare even for cave fills. For many, the extra margin of safety related to having more gas offsets the increased risk of overfill and catastrophic tank failure. If tank failures were more common, the fill bank at Amigos would be considered a WMD.

FWIW, a 100 ft3 tank at 4,000 psi would have a 1 psi blast radius of over 100 meters (enough to break windows).

 

[adurso]

Not at all, if the tank was inside the apartment when it blew it could easily create that kind of damage and move someone. The explosion here in Fayetteville earlier this year did a lot more than shattering windows and it blew people across the room.

Gypsyjim's posit was the victim in the door moving outside, tank not in apartment....open door allows pressure to equalize quickly, less likelihood of overpressure...

 

[57Writer]

From ABC News: Scuba Tank Explosion Kills Iraq War Veteran Russell Vanhorn - ABC News

 

[PittCaleb]

wow, another excuse for people to bash on cave fills..assuming the tank passes muster overfilling lp steels isint going to do anything but shorten its life.

Been lurking on this thread. Define "shorten its life" - if by that you mean catastrophic failure sooner rather than later, I think that's what we saw here. If you mean something else, I'd be interested in what that is. I am no diving expert, nor a cave diver, nor a metallurgical scientist. I happen to know one of each, but none have access to the tank in question.

PittCaleb

 

[JahJahwarrior]

The disk itself has no threads however some brands are sold as a captive disk held to the retaining nut with the brass crush washer. I do find it interesting that they didn't make different threads or disk sizes based on pressure to require the correct disk.

There is certainly a reason it is kosher to double up on low pressure steel tanks compared to other tanks: to overfill them. Cave divers do not tend to overfill aluminum tanks or high pressure steel tanks, so there is no reason to use the incorrect burst disk.

Keep in mind that European tanks don't have burst disks, and Australia requires yearly hydro. The fact that a government agency made a rule doesn't mean it's necessarily necessary. Though as always I do not condone violating any rules or laws or industry standards.

I really see no need to make this a discussion about overfilling steel tanks until we know if it was a steel tank. For the same reason, I have not started lecturing on the dangers of 6351 aluminum tanks. I also don't understand why some are so hung up on where the tank ruptured, or whether there must be a fireball for something to have exploded.