Page 1 of 2
Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 8:19 am
by Bryan
I don't see how a ruptured burst disc could cause this....Must be more to it...Very sad news.
http://www2.tbo.com/news/breaking-news/ ... ar-256967/
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 10:28 am
by 8dust
No, there’s no way at all.
There has to be a lot more to it. Definite monkey business at work.
I don’t see even a large capacity tank with a catastrophic failure being able to create enough over-pressure in an apartment to blow out the windows and door, and if there was… the other people in the apartment would have some bleeding ears at the very least… not possible that they would be “fine.” A scuba tank is not claymore or otherwise shaped charge. The pressure in the entire enclosed space would have to be enough to blow the windows and the door.
Ruptured discs or broken valves create projectiles, not bombs, and 95% of the time the failures will translate to rotation, not straight-line motion. Broken legs or anything else that gets in the way, but not
multiple windows
and a door.
It is very sad, and I feel for the young man's family, especially as he had survived a war only to lose his life pursuing a passion such as ours, but there is no possible way this happened as described.
I hope he gets some justice.
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 10:30 am
by sthtxdiver
Man oh Man that is very sad news
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 11:18 am
by DaleC
Yes, there seems to be more to the story than that. Either a poorly/non inspected tank, cave fill with double/triple burst disks that failed or perhaps he dropped it just the wrong way.
Thank goodness Billy Hussey, the manager of EZ Scuba Diving on Hillsborough Avenue in Tampa passed on accurate information:
"...However, some scuba shops will let a tank cool and then top it off. Doing so doesn't leave any room for the gases inside to expand when it is hot outside, Hussey said.
...Scuba tanks made prior to 1990 – which some divers still use – were made using an alloy that was known to crack around the neck of the tank, Hussey said. Those cracks make the tanks susceptible to exploding."
That's the professional inspecting your tank.
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 1:15 pm
by Bryan
I hope....I say I HOPE the store owner was taken out of context or simply misunderstood by the reporter...If he is that ignorant he should lock the door and take up golf....
In Florida if you bring an aluminum cylinder in for an air fill be prepared to jump through a million hoops and even then it is very likely that you will leave with no air. If it's over 10 years old many stores wont even bother to check the hydro/visual on it. Simply No Air For You.
Even on pre 98 aluminum cylinders there is no reason not to fill them if they are properly tested as outlined by the manufacture and DOT guidelines for eddy current testing.
Around here many divers slug the burst disc or double up on them and fill aluminum 80's to 4k.....I won't try and explain it like Luis can but when you take a cylinder inspection course THEY BEAT IT IN YOUR HEAD over and over that aluminum will not stand up to repeated overfilling beyond it's rated pressure. Steel is a different story...I have had more than one argument with people wanting "Cave Fills" and I simply won't do it...Why would someone risk their life for a $5.00 air fill????
I'm not saying this was what caused the explosion I'm simply ranting about FLA and 3AL
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 5:13 pm
by Gilldiver
The best analogy on tanks I have heard is that, for aluminum mostly, they are like the tires on your car, sooner or later they do wear out.
The exception to this rule is the steel 72's that are just so over engineered we just don't have a problem with them as long as we follow some simple rules - like don't get water in them.
Re: Scuba tank explodes in St Pete
Posted: Mon Sep 12, 2011 6:38 pm
by antique diver
8dust wrote:No, there’s no way at all.
There has to be a lot more to it. Definite monkey business at work.
I don’t see even a large capacity tank with a catastrophic failure being able to create enough over-pressure in an apartment to blow out the windows and door, and if there was… the other people in the apartment would have some bleeding ears at the very least… not possible that they would be “fine.” .
A cylinder rupture absolutely can cause the destruction shown! I was called in to determine the cause just after a moisture separator on a compressor came apart at 4000 - 4500 psi. I got there before they cleaned up the considerable mess. Keep in mind that was a cylinder about 4" in diameter and 15" long, and the damage to the dive shop was fairly comparable to what you see in the photos.
Inside walls were "rearranged", one with enough force to shatter the toilet in an adjacent room (luckily no one was sitting there)
The front (aluminum frame & glass) of the shop in a strip center was moved forward at the base by two inches. The compressor was in the back of the shop, isolated with a sheetrock and stud wall that took most of the blast and probably prevented the front glass from blowing out. One person was in the compressor room, but remarkably escaped with only hearing damage and one small scar from shrapnel. After seeing how that room was rearranged I can't understand how he escaped worse injury. Don't underestimate the destruction possible from a Scuba tank rupuring.
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 12:14 am
by 8dust
Well... I'll be the first to admit that I don't know too much more than I have to about tanks, and even less about compressors... but I do know a little something about stuff that goes boom, and how shock waves perform/behave... and I just don't see it. Not from a tank, and not under relatively normal circumstances.
With any luck, local police will call in the state crime lab, and if there is fault to be found, it will be found regardless of whether it was from overfilling, mishandling, or foul play.
Again, I feel very sorry for the individual and his family.
p.s. - I in no way underestimate the destruction possible from a Scuba tank rupuring and hope I never find out. You may remember about a year ago when I wrote in to ask advice on a ST72 that I checked the pressure on before a dive, only to find that the shop had topped it off to ~3200 if I remember correctly... scared the SH*T out of me as I backed quietly out of the room... I'm not even a big fan of riding with them in the back seat of the truck. Lots and lots of stored energy there fo sure!
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 7:45 am
by Bryan
Clues suggest pure oxygen may factor in fatal St. Petersburg scuba tank blast
http://www.tampabay.com/news/publicsafe ... nk/1191201
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 8:32 am
by crimediver
This is pretty bad. I also thought about cave fills and the burst disc being doubled up as it seems to be a fairly common practice down there. I could not open the last link Bryan posted about the oxygen connection but I am sure this will all be figured out sooner or later.
I also have seen a couple of scuba related explosions and can testify that the force will do some serious damage. There is enough potential energy in an aluminum 80 to toss a fire engine over a building. I was in Madiera Beach when a compressor head cracked and it damaged much of th masonry walls in the building as well as removing all the windows. There was another recent exposion with a tank that was pretty catastrophic but it was a scuba tank with O2 in it. In that case the tank was dropped.
I knew there had to be a good reason that I make my old lady carry my tanks..
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 9:10 am
by 8dust
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 12:21 pm
by captain
Some reports that it was an AL 40 which supports the oxygen theory by it possibly being a deco cylinder.
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 3:28 pm
by crimediver
-"According to one scuba tank inspection expert, "The explosive potential in a fully charged 80cf aluminum SCUBA cylinder is approximately 1,300,000 foot pounds -- enough to lift a typical fire department hook-and-ladder truck over 60 feet in the air!", stated by A. Dale Fox on his web page." (note that that is CF not inches)
A 40 cf tank does sound like deco tanks. Being only a 40 cf I guess that would only launch a hook-and-ladder truck only 30 feet in the air.
Anyways, it is enough to kill you. The big question is what triggered the explosion?
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 5:37 pm
by antique diver
crimediver wrote:-"According to one scuba tank inspection expert, "The explosive potential in a fully charged 80cf aluminum SCUBA cylinder is approximately 1,300,000 foot pounds -- enough to lift a typical fire department hook-and-ladder truck over 60 feet in the air!", stated by A. Dale Fox on his web page." (note that that is CF not inches)
A 40 cf tank does sound like deco tanks. Being only a 40 cf I guess that would only launch a hook-and-ladder truck only 30 feet in the air.
Anyways, it is enough to kill you. The big question is what triggered the explosion?
I'm sure not an explosives expert, but I personally think that whoever said that about the truck being launched 60 feet in the air is extremely confused. Nooo... on second thought, I think he is just full of crap.
"Enough to kill you"... absolutely! That's a proven fact.
Re: Scuba tank explodes in St Pete
Posted: Tue Sep 13, 2011 11:30 pm
by crimediver
I suspect it would not launch one if it went off underneath one as the gas would dissipate in every direction. The point is there is enough potential energy that it could do it if it is harnessed properly.
I have had a shotgun with an automatic ejector kick out a loaded paper shot shell of #8 birdshot one time on a gravelled road. The primer was dented by a rock and exploded harmlessly as the explosion was not contained in a chamber or barrel. The shell split and the crimping opened up some. If it had been chambered and fired it could a lot of serious damage downrange.
I have used Scott airpack SCBA bottles to inflate rescue lift bags used in vehicle extrications or other rescues that can easily lift train box cars. I regularly use an inflatable jack that will lift your car by placing a hose over your tailpipe exhaust. Expanding gas has a lot of power. It just depends on how the energy is contained or dissipated.
