Carbon fiber tank failure.

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Bluecup

Bluecup

Member
Sep 2, 2018
258
8
New York, United States
Good evening,

Can anybody provide a link or any info on Carbon fiber tank failure. I have found video of severe over pressure testing failures but can not find any accident reports. There are a couple reports on Aluminum SCUBA tank explosions but no carbon fiber. My son is a bit of a know it all and is giving me a hard time about how dangerous they can be.

Thank you,

Jim
 
There's lots of history on why the US has a 15 year lifespan on carbon fiber tanks, but considering that the tank holds 4500 PSI, and so few failures occur, it's a testament to the quality of the tanks. 22 Plinkster on YouTube shot a couple pressurized tanks with a large caliber air rifle, and the results were amazing. He was about 100 yards out and the tank blew past him.

Lots of debate as to whether the 15 year rule is good or not, but it is currently what it is.

I don't know of any video of tanks failing, as not expect anyone to know what it will fail, but damaged tanks can be weakened, and corroded tanks can fail, so just treat the tanks with respect and live to shoot another day.
 
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Burst disk don't prevent the tank from rupturing from anything but being over pressurized...

I don't believe a tank with an intact CF wrap can 'explode' outside of extreme conditions... burst at a weak point in the aluminum core or where the CF has been damaged, yes. That would equate to a quick air release and bottle bouncing off the walls (and you if your in the way) amount of damage. Not pleasant but not blow out the corner of your house damage.

Not trying to sound knowledgeable or convince anyone but think about the fire department.... they carry these things on their backs into infernos that would quickly kill an unprotected person. Ever been to an active fire station? The bottles look like they've been through hell, yet they strap them to their backs. Maintenance!!!
 
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I posted this thread in hopes of getting a definitive answer to settle a dispute between me and my son. I see now that this is not so cut and dry, on one side I can see the absolute need for safety testing for the what if factor and why hydro testing is a necessity, however if it is more likely you will get struck by lightning twice in the same day before a flawless carbon fiber tank will fail, where do we draw the line. I always air on the side of caution but I am not sure it is called for here.

Thank you,

Jim
 
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Burst disk don't prevent the tank from rupturing from anything but being over pressurized...

I don't believe a tank with an intact CF wrap can 'explode' outside of extreme conditions... burst at a weak point in the aluminum core or where the CF has been damaged, yes. That would equate to a quick air release and bottle bouncing off the walls (and you if your in the way) amount of damage. Not pleasant but not blow out the corner of your house damage.

Not trying to sound knowledgeable or convince anyone but think about the fire department.... they carry these things on their backs into infernos that would quickly kill an unprotected person. Ever been to an active fire station? The bottles look like they've been through hell, yet they strap them to their backs. Maintenance!!!
Click to expand...

Yes, maintenance. Also strict compliance with manufacturer recommendations and Federal law!

I'm retired fire service. We did not discuss theoretical versus real life spans, possible failures, or the expenditure of life critical funds. When the schedule called for cylinder disposal we got rid of them.

Note I'm not judging anyone. Rather, I am responding to the example of fire department use and why we could confidentially run into burning buildings with a SCBA cylinders from "hell" our backs. Please note, I would personally not use expired or salvage FD cylinders unless they had gone through the Air Venturi process, or something as equally comprehensive, which appears to be a sound and approved inspection process.

Let me emphasize that it is not my place to judge in regards to personal choices. I write this in spite of the fact that I used to have to respond to pick up the pieces (literally) when personal choices resulted in calamity. It was only tough and sad duty when one person's choice negatively impacted others who had little to no say in the calamity causing choice.

In brief: I've never seen a properly maintained cylinder, within lifetime limits, catastrophically fail. I do not wonder why. I choose caution over thrift.

Best wishes to all.

The other Mark B.


 
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As we have more home compressors we will see about the tanks, I think we will have more tanks leaking and blowing air out,

about 0 % bombs , I do not be leave the bomb scare of the 4500 psi tanks ,

The public would not be able to buy them, WE got big brother looking down our shoulder on every thing we do, No bomb just a pop and a psssssssssssssssssssssssssssssss.

Yes safety , I do not fill my small tank between my legs any more, 

Mike
 
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In an Ideal world you would reach YIELD failure before BURST failure, which would hopefully be visible to the next eye in terms of deformity, if taken beyond yield into the burst failure the result of such entirely depends on the size of leak, a small rupture would essentially limit the air escaping, a fairly large rupture would nearly empty the tank all at once creating a 5 lb or so projectile...



Fortunately for us, scuba divers, fireman, and people of the like, compress dry air doesn't make great bombs...4500 psi seems like a lot, but between the acceleration of the gas and its mass, little damage from air itself can be done unless it was streamlined and directed to a small portion of skin of course...then it would likely cut, like a drunk laser...but air expanding into atmosphere quickly dissipates and loses acceleration thats why longer barrels provide us with more fps/fpe!



HPA should be taken seriously but when handled with proper care and maintenance, the chances are you're good.






 
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Ackuric,

If I am understanding you correctly a carbon fiber tank would basically blow up like a ballon before bursting. It would also start to leak slowly before completely bursting open and when that would occur it would rapidly dissipate into the air.
Click to expand...

Here is the only documented "explosive failure" that I have been able to find. Apparently the tank had been laying on a floor awaiting to be refilled when a bottle of Aluminum cleaner spilled and the tank sat in it. Several days later the tank wound up "exploding" inside a fie truck.



https://www.fireengineering.com/articles/print/volume-149/issue-11/features/acidic-fluid-leads-to-air-cylinder-failure.html
 
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Bigtinboat,

Holy cow over $5000 worth of damage! This again is one of the fiberglass and plastic type bottles I still have not seen any of the newer carbon fiber tanks burst. We need to hear from some more fire fighters or maybe someone from the dot. I think I will try to e-mail the dot tomorrow and see if I can get some info.

Thank you for the help,

Jim
 
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If you are interested in a very detailed study on carbon SCBA's, go to the Department of Transportation(DOT) web page at the following link:

DOT SCBA Study

When you are at this page, you can download the study report. There is a link on the right side of this page to download the report. Just not that it is a MASSIVE file to download and will take a while. There is lots of good information in here about all of the torture these tanks were put through before the DOT allowed these tanks to be life extended to 30 years of life. Today you can use tanks to 30 years if life extended via the requirements of Special Permit 16320, link below:

SP16320
 
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I'd simply add that an engineer somewhere had to put his PE's stamp on a plan/design somewhere...and I can guarantee you the end of life safety factor was not based on coming up to the edge of 15 years...there's a lot of additional safety factor built in. Which is one reason why the DOT actually permits (licenses) the LE (Life Extended) program. 


 
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