Risk with 1972-1988 AL80 Tanks ?

[JahJahwarrior]

I must be a crazy man because I can never figure out how people become so fixated with the minute perceived risk of 6351 tanks while apparently ignoring the very real risks all around them. Have any of those opposed to these tanks quit driving? The risk is far greater of dying in a car wreck. Walking outside in a storm? The risk is far greater of dying via lightning strike.
Tech diving? Wreck diving? Cave diving?
If such minute risks bother people how do they ever suit up and SCUBA dive at all? The risk is far greater that you will die from that act alone, than from a 6351 tank.

The difference is, my driving is most likely to kill me (though, car accidents are the worst analogy from my position, because they are most likely to involve innocent people, I'm just assuming here that a large bit of accidents involve only the driver or occupants of the crashed vehicle). Walking around in a storm, will only hurt me, and won't hurt myneighbor. Tech, wreck and cave diving, all can kill me, but an exploding 6351 cylinder can kill the tank monkey.

Also, it is easier to mitigate risk with other events. Airbags, or a tall metal pole situated near you to distract the lightning. The only way to prevent damage to a tank monkey from a 6351 explosion is to always transport the tank ina bombproof box, which makes diving it pretty hard

Since 1972, 22 aluminum SCUBA tanks have been reported to have exploded. Over the same time period, 56 Steel SCUBA tanks were reported to have exploded. In general, the failures of both types were due to abuse, improper maintanance and improper inspections.

Reported where? By whom? If you have such precise numbers, surely you can provide a credible source? Also interesting, how many people were hurt in each of those instances? Do aluminums or steels tend to be more catastrophic when exploding?

 

[DaleC]

Also, it is easier to mitigate risk with other events. Airbags, or a tall metal pole situated near you to distract the lightning. The only way to prevent damage to a tank monkey from a 6351 explosion is to always transport the tank ina bombproof box, which makes diving it pretty hard

Actually, you are undone by your own logic. There is a very simple way to mitigate the risk from a 6351 cylinder. Do a proper Visual inspection. There has not been a single reported case of catastrophic failure in such a case.

Reported where? By whom? If you have such precise numbers, surely you can provide a credible source? Also interesting, how many people were hurt in each of those instances? Do aluminums or steels tend to be more catastrophic when exploding?

Read the thread I linked. In it you will find all the supporting data. It's funny that so many people know someone who was right there when the 6351 tank exploded yet there have only been a few actual cases (pre VE testing), and each one has been well documented.

 

[klauricella]

This is the Luxfer site with the correct info. These are the guys with all the liability so it is their butts that will get sued. It is from 2007 at that point there have been 11 scuba failures and only 6 in the US. Also how many dive shops fill tanks out by the general public or where the tech stands over the tank when filling, my local shop just changed their setup to cover everything up to prevent an accident. Also home many of the tanks with problems where properly inspected.
Luxfer: Sustained-load Cracking FAQ

 

[zaberman1]

I found the luxfer site VERY informative...out of the 20 million AL cylinders, 6 have exploded in the US due to SLC....Compare that to steel

 

[cbrich]

I found the luxfer site VERY informative...out of the 20 million AL cylinders, 6 have exploded in the US due to SLC....Compare that to steel

Out of those 6 how many exploded since the the requirement for eddy current? Appears to be 2005.

1 in the United States since 2005, but no injury. Out of the 6 injuried, 3 are from Florida, and 1 from Hawaii.

 

[zaberman1]

there is always a risk filling cylinders, my question is, how does the 6351 AL cylinder relatively compare to AA or AL 6061 in explosions?

 

[PhilEllis]

there is always a risk filling cylinders, my question is, how does the 6351 AL cylinder relatively compare to AA or AL 6061 in explosions?

You are clearly correct. As with all things in business and industry, there is certainly risk in filling high pressure cylinders. That said, I personally believe that the gradual voluntary removal of 6351T6 cylinders from the market is a step toward removing an unnecessary risk. While no one can quantify the risk that would be removed, we certainly know that 6351T6, aside from other alloys, represents a known risk that can be completely eliminated through obsolescence.

Phil Ellis
www.divesports.com

 

[mike_s]

A while back a little shop down in Bama that I have a lot of respect for was filling a 6351 cylinder. They were doing everything right and still had one slip by them. When they decided to no longer fill 6351 cylinders I had to nod my head in agreement as I did not blame them. Glad that shop the folks that run it are still around.

I remember that incident as I was in that shop the day after it happened and saw the cylinder that had a crack in it.

It made me change my stance on thinking these tanks were ok if properly inspected.

This tank had been through two inspections, one at the hydro facility and one at the shop and it didn't fail until they started to fill it.

After seeing this, I fully agree with their stance now not to endanger anyone by refusing to fill these tanks.

 

[Get out and Dive]

Every diver has a right to call a dive, every bartender has a right to refuse service and every fill operator has a right to decline to fill a tank.

If you disagree with that, you find a new dive buddy, a new bar or a new fill station. Just sayin! Risk is a personal thing - just don't disguise it as an absolute truth - 4 pages of posts shows that does not exist.

 

[WD8CDH]

<snip>but what is wrong with doing an eddy current test on 6061 and steel tanks? My LDS does it, and they don't charge for it, they need to keep prices the same as the other dive shops. A visual for a 6351, 6061, and steel tank cost the same at my LDS. Do I care if they do an eddy current test on 6061 or steel, NO. However with that said if my LDS charges more for a visual with eddy current, than a visual without eddy current; I would be finding another LDS very quickly.

1. They could be failing tanks that are perfectly good.

2. For the same labor cost, they could have done a more thorough visual inspection of the steel or 6061 tanks.

3. If they just don't do the eddy current test when not needed, they could just keep more profit and possibly stay in business longer.

I think it is perfectly acceptable to charge more for a visual eddy as long as they don't perform visual eddy on tanks that don't need it (see #1).