Omg..... what do I do?

[Br44]

i found this artical while browsing the internet...... please read

Tank Explosion - April 19, 1999
Aluminium Scuba Tank Concerns - Visual Plus
At Beaver Aquatics we were intimately connected to a catastrophic explosion of an aluminium, 80 cubic foot SCUBA tank. With this in mind, we would like to inform people about the dangerous potential of SCUBA tanks.

Information and links are included about the explosion of an aluminium SCUBA tank at our facility and other explosions, and will explain some of the procedures that have been developed to make us aware of potential problems before they progress to catastrophes.

Bryan Erickson's Account (April 1999)
What has happened in the last week?????

My week starts on Monday (April 19), arriving at the store late ( hey, I'm the Boss). Kevin Bates, (my right hand), isn't feeling very well, so after harrassing him, I send him home. A customer comes in complaining about his dive computer. As I am dealing with him, another fellow comes in with a tank for fill. Hydro date checked (05/98), VIP checked (05/98). I take the tank into the back and attach the fill whip, check the pressure regulator and turn it down (3000) as H/P steels were being filled before that (3500).

I turn on the airbanks and go back to the front of the store to look after my customers while it fills. We had a flow restrictor put in by Aqua Tech West in the fall, so the fill process is somewhere around 3-5 minutes, depending on how much air is in the tank when it arrives. After 1-2 minutes the cylinder explodes into 3 different pieces, (guesstimate on pressure 2200PSI) the valve (not one of the pieces) is still attached to the fill whip.

Later that day we check the burst disc which, of course, is intact. The cylinder was manufactured by Luxfer 9/74. By the appearance of the cylinder it was in very good condition. No corrosion around the neck area, no dents, hardly even a scratch on the original paint and decals (USD). After the explosion the pieces were recovered and the interior was examined. NO pits, it looks perfect, the slight discolourization on both sides of the threads leads me to believe neck cracks.

This account tells the immediate story concerning the explosion. The subsequent story would include dealing with government agencies, insurance companies and investigators for the next 12 months looking for answers. What was frustrating on our part was the lack of knowledge about the concerns for older aluminum scuba tanks. Damages ended up to be in the $20,000 CAD range. We were extremely lucky that we were only dealing with damages and not injuries or death. The investigation did come to the conclusion that sustained load cracking was responsible for the cracking.

After surviving this incident we have developed strong feelings about the need for all tests on Scuba tanks including Visual Plus (eddy current detection). We have experienced the potential that these tanks do contain. No one else has to experience this same devastating situation if these tests are being done by everyone. Please keep your Hydrostatic test and your Visual Plus inspections up to date so you don't have to experience a SCUBA tank explosion.



after reading that i had a bad realization and checked my dads old tanks(that he still uses)

guess

(if you guessed Luxfer 1974 then your right)
should i get hin new tanks?
i hear that steel 100's are really good quality

 

[bleeb]

after reading that i had a bad realization and checked my dads old tanks(that he still uses)

guess

(if you guessed Luxfer 1974 then your right)
should i get hin new tanks?
i hear that steel 100's are really good quality

You might want to have a look through the Tanks, etc., section of ScubaBoard. (This thread probably belongs more there than in "Near Misses". The Original Poster can ask a Moderator to move it there, if desired.) This topic seems to come up at least about once a month. In particular, see the following thread: http://www.scubaboard.com/forums/tanks-valves-bands/248026-1989-luxfer-cylinder-vip-refusals.html The following is what I've picked up over the years from reading here on SB and elsewhere.

In summary, tanks made with 6351 aluminum alloy are susceptible to a failure mode called Sustained Load Cracking (SLC) while tanks made from the more common 6061 alloy aren't. Some people and organizations believe the Visual Eddy inspection process is sufficiently likely to detect the onset of cracks before they become problems (i.e. between annual inspections), but there have been a few (one or two) reported cases of tanks failing immediately after an inspection.

As a result, some dive shops will not fill tanks that haven't been inspected by Visual Eddy+, others won't fill tanks that haven't been inspected by someone they know, while yet others won't fill tanks older than x, often 1990 but I think I've heard of shops with cutoff dates as late as 2000. It's up to them, so be aware of the policies of whoever you normally get fills from.

To give you a sense of the scale of the problem, IIRC (vague memory here) there have been between one and two dozen actual failures during filling, out of 10-20 million tanks manufactured, although probably the majority of those tanks have now been withdrawn from service and so aren't being filled regularly. OTOH, most of those failures involved major damage to the fill facility, and some resulted in injuries, although I can't remember whether anyone has actually been killed. As a result, some degree of concern by fill facilities is understandable.

The post quoted below lists the tanks covered by the recalls. Note that some manufacturers have never made tanks out of 6351, and so are not affected by the recall. Based on this, it sounds like your dad's 1974 Luxfers should probably be condemned, but you can check Luxfer's web site if you want to be sure.

Not that it helps but the DOT published a list of tanks made from 6351-T6 aluminum.

The Department of Transportation has released the following list of scuba tanks that are most likely to be made from the 6351-T6 aluminum alloy to which a disproportionate number of tank explosions are attributable:

All DOT3AL tanks manufactured under one of the following exemptions or
special permits: 6498, 7042, 8107, 8364, 8422;

All composite cylinders manufactured under one of the following exemptions:
7235, 8023, 8115;

All Walter Kidde DOT3AL scuba tanks;

Cliff Impact DOT3AL scuba tanks made before July, 1990;

Luxfer 80.8 cu. ft. scuba tanks (S80.8) made before May, 1987;

Luxfer 72 and 100 cu. ft. scuba tanks (S72, S100) made before August, 1987;

Luxfer 80 cu. ft. scuba tanks (S80) made before January, 1988;

Luxfer 50 and 92 cu. ft. scuba tanks (S50, S92) made before April, 1988;

Luxfer 30 and 63 cu. ft. scuba tanks (S30, S63) made before May, 1988;

Luxfer 40 cu. ft. scuba tanks (S40) made before June, 1988;

All other scuba tanks made in the U.S. before February; 1990 (except Catalina);

All scuba tanks not made in the U.S.


Per the DOT list, a Luxfer 30 made in May of 1988 or later would be made from 6061-T6 alloy and would not be suceptible to sustained load cracking.

Personally, I tend to avoid shops with policies of not filling properly inspected tanks given that there has been no incidence of a properly inspected 6351-T6 aluminum alloy tank exploding since the implementation of eddy current inspections over 8 years ago. Filling one is not a safety hazard and shops that suggest it is are either ignorant or are perhaps trying to promote tank sales by telling you your tank is unsafe. Either one woudl be reason enough for me to take my business else where.

 

[Rick Murchison]

The "official" DOT position on these tanks says you can continue to use 'em so long as they keep passing hydro and eddy-current inspections.
However... I know of one report (by Phil Ellis on this board) where a dangerous neck crack showed up right after a successful hydro/VIP+, which has changed my personal opinion to "make it a wind chime; buy a new one."
Rick

 

[DA Aquamaster]

I am a firm believer in doing the eddy current/visual plus inspection after the hydro test as I have seen previously non observeable cracks appear during the hydro test.

That runs counter to the traditional way it is done - which is largely based on the philosophy that it makes no sense to waste the time hydro testing a tank that ultimately fails the VIP portion of the requalification. What ever the reasoning, people get their noses seriously out of joint if you suggest doing the VIP last. In my opinion that is a solid argument for shops to do their own VIP and visual plus inspection after a 6351-T6 alloy tank returns from hydro - but again, many shops do it before they send the tank in.

None the less there has not been a catastrophic failure of a 6351-T6 alloy tank due to sustained load cracking since eddy current/visual plus inspections were implemented in 2000.

Personally, I would not buy a 6351-T6 alloy tank, but I also would not pull one I owned from service as long as it is properly inspected.

 

[PhilEllis]

The "official" DOT position on these tanks says you can continue to use 'em so long as they keep passing hydro and eddy-current inspections. However... I know of one report (by Phil Ellis on this board) where a dangerous neck crack showed up right after a successful hydro/VIP+, which has changed my personal opinion to "make it a wind chime; buy a new one."
Rick

I have made several fairly extensive posts on the "incident" that Rick references, though I am unable to find them this morning. I will spend some more time searching and post a link to those posts. As Rick has referenced, we did have an incident of a cylinder neck crack "opening" immediately after a successful hydro and VIP+ test. Most troublesome is the fact that we did a fairly extensive visual inspection of the cylinder neck just before filling the cylinder. Yet, the neck still "opened" and resulted in an active leak. As a side note.....I can't begin to describe the feeling when I realized that we had an active neck leak. I will never forget that sound, nor will I likely ever be that scared again.

I am a firm believer in doing the eddy current/visual plus inspection after the hydro test as I have seen previously non observeable cracks appear during the hydro test.

That runs counter to the traditional way it is done - which is largely based on the philosophy that it makes no sense to waste the time hydro testing a tank that ultimately fails the VIP portion of the requalification. What ever the reasoning, people get their noses seriously out of joint if you suggest doing the VIP last. In my opinion that is a solid argument for shops to do their own VIP and visual plus inspection after a 6351-T6 alloy tank returns from hydro - but again, many shops do it before they send the tank in.

None the less there has not been a catastrophic failure of a 6351-T6 alloy tank due to sustained load cracking since eddy current/visual plus inspections were implemented in 2000.

Personally, I would not buy a 6351-T6 alloy tank, but I also would not pull one I owned from service as long as it is properly inspected.

Deciding how to handle 6351-T6 cylinders is certainly a decision that one must make with some serious degree of deliberation. Given our previous experience with the active leak, in spite of the successful hydro, VIP+, and a rather exhaustive visual inspection, I could never make the decision to leave these in service.

With regard to failures since 2000....I believe that the gentleman that was badly injured in New England (RI I think) in 2006 was injured by a 6351-T6 cylinder that had all of the proper inspections. In fact, I would classify the cylinder that actively leaked in our store as a failure....it just didn't explode.

It is my deliberative view that these cylinders are bad news. Were so many of them not removed from service over the past number of years, I suspect that the news would be worse. The DOT clearly stopped short of recalling these cylinders. But, they did put special operational "quidelines" for filling them in place that they have NEVER put in place for any other cylinder. Certainly Luxfer wanted them "out of the market" for some reason. Noting else would explain the campaign to offer "gift certificates" for return of these cylinders. I realize that they stopped short of recall, but I expect economics and other factors entered into that decision.

There is also lots of "whistling through the graveyard" and misinformation about these cylinders and this aluminum alloy....often advanced by those (mostly individuals and possibly an organization) who have a primary mission of keeping these cylinders in service. It certainly is no surprise to the aerospace industry that this alloy is subject to cracking, either sustained load cracking or corrosive load cracking. There are numerous reports of it in aerospace documents. I have even seen such irresponsible statements, such as "they reduced the amount of lead in this alloy on some date to reduce the possibility of SLC". This statement, I believe, was made here on ScubaBoard by a regular poster. (again, I will do some searching, or maybe someone else will) This could not be further from the truth. Beyond trace amounts, there is no lead in 6351-T6 alloy. If "anyone" had "altered" 6351-T6 by "changing the amount of lead in the alloy", then it would no longer by 6351-T6. There is no lead in 6351-T6 alloy, at least not the registered version of the alloy.

There is a simple solution....QUIT USING THESE CYLINDERS. TAKE THEM OUT OF SERVICE. This would eliminate the risk, end the speculation, and maybe prevent some future accident. After all, they have all long ago returned the investment made by the purchaser.

Anyway, just my opinion.

Phil Ellis
Discount Scuba Gear at DiveSports.com - Buy Scuba Diving Equipment & Snorkeling Equipment

 

[DA Aquamaster]

The only catastrophic 6351-T6 alloy tank failure I am aware of since 2000 occurred for reasons other than an SLC. In one case the injured party tried to devalve a full O2 cylinder (valve was stuck and would not open to release the contents) and another where a full O2 bottle fell off a bench. In either case the failure would have resulted with 6061-T6 alloy as well.

Given the hundreds of thousands of 6351-T6 tanks in in scuba, SCBA, medical O2 or CO2 service, if properly inspected tanks were catastrophically failing we'd be hearing about it on a regular basis.

In my experience, many 6351-T6 tanks are removed from service every year by test facilties all over the country when they fail inspections. That is in my opinion the key to preventing catastrophic failures and validates the inspection process.

However it is also obviously true that removing all of them from service now would accomplish the same thing, so it becomes a philosophical issue whether removing a tank from service prior to the end of its safe working life, and denying the consumer the remaining useful life and value of the tank, is desireable as a means to prevent the very slim chance that one non inspected tank that also happens to have an SLC may eventually fail.

I have no doubt that will eventually be the case when the number of 6351-T6 tanks in service falls to fairly low levels and the cost to ehe end users of that action is also proportionately small, but i think we are still a long way away from that.

 

[sweir]

First thing is to remember that you are reading an 8-year old article. How many exploding tank stories have you read since then? None (at least none that I have heard of, and as a writer for Diver Magazine I have been writing about the tank issue for sometime). Most stores in Ontario, Canada are unwilling to fill the affected Lux. tanks and will give owners a $100 trade-in on new tanks. A visual and hydrostat of your dad's tank should be enough though to allay any fears of an explosion. I really trust the judgement of the dive shops I frequent (and the tank only blows up when it is getting filled) and I would never insist on them filling a tank they don't want to. I am using 4 alum. tanks that I have had since 77 and they continue to pass inspection. Will begin trading them in once the X-mas rush is over.

stephen@stephenweir.com

 

[DoubleHoseDiver]

Did I ever say I like steel tanks!!!! I'm glad no one was in the restroom!!!! Tim

 

[Scared Silly]

Br44 search is your friend this gets discussed ad nauseum.

http://www.scubaboard.com/forums/tanks-valves-bands/233341-conducting-your-own-vis.html#post3552370

BTW Welcome to da board.

 

[JahJahwarrior]

After reading posts by people like Phil Ellis, and seeing the pictures of an exploded tank, I personally do not savor the use of filling of these tanks.

I have a 1984 Luxfer tank in decent shape, last hydro 05, vipped in April of this year with the Visual+system, anyone want it for a decent price? Totally serious, I need to sell it!