Joe Shneehagen accident

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Airgun Al said:
This was a very serious situation, and I wish Joe the very best, in his recovery.
A tank exploding is very alarming.
A few of the members comments in the previous thread were equally alarming.

Careful when filling

It blew around 3000
www.airgunnation.com www.airgunnation.com
Instead of waiting for facts, learning from the incident, and attempting to prevent it from ever happening again, a few members in the previous thread were quick to cast doubt, and choose to make fun of the seriousness of Joes extremely serious injuries.

In my opinion, this event should be a reminder to inspect our tanks condition, expiration dates, and be aware of the fill limits of the gear we are using.
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To be clear, NOBODY made fun of the seriousness of Joe's injury in the other post - because until very late in the post no clear indication of any real event was provided. Most of the posts you referenced were questioning the very flawed data that the OP offered up (and later revised/deleted), and a few did start to openly ridicule the original poster's comments, including a reference to an injury, but nobody was making fun of what had happened to Joe once it was known.

Truth be told, we still know very little about the actual accident, and we don't even know if what was shown/reported in that thread was actually linked to Joe's accident.

I hope and pray for speedy rehabilitation for Joe, and that all works out as well as it can . . .
 
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JimD said:
I think there are too many unknowns. I wish there were fewer. If Joe was injured filling an airtank I think it makes sense that it was a solid metal one. The carbon fiber tanks seem to have much more margin against any sort of catastrophic fracture. That statement is based upon the aluminum bottle failure much more dramatically at a much lower pressure than a badly damaged carbon fiber tank in the earlier thread about bottles. The picture in the "be careful filling" thread does not seem to be a carbon fiber reinforced tank. But the timing is the only thing I know of that would suggest the two topics could be related.

Perhaps a better title for the "be careful filling" thread would be "know what you are filling". For a bottle to fail at 3000 psi it has to be either badly damaged or never intended to hold 3000 psi. I only have one SCBA tank and it is an expired firemans Scott tank. There is nothing in these threads that makes me more concerned about filling it to 300 bar. But I would like to know more.
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None of that explains why the burst disk did not blow first. I have blown many burst disks filling aluminum paintball tanks. It happens on a regular basis as the tanks warm up in the Florida heat. I want to know where the tank came from. The burst disk is supposed to prevent these things from happening.
 
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this link has no discussion about the why , but is about a raffle to help him.. Joe the victim in this accident

we as users have Questions about the why and how this happened, for our and other users safety, to have better understanding of the particulars and what needs to be avoided,,, I have my opinion but it is just an opinion until evidence is openly examined and facts displayed
we can see what appears in the photo but "Paul Harvey" needs to comment on the rest of the story,,, or the rumors and guessers will continue

as we all have good thoughts and hope and prayers for his recovery
 
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Firewalker said:
You all keep on keeping on, by the looks of it, the tank bisected itself and I've seen intergranular corrosion and gallium contamination do the same in sheet goods from Reynolds before we got a recall notice.

I'd like to know what happened but I'm not going to change what I am doing, I inspect my Luxfer CF tanks every year and because I dont want to destroy them, there is no way in heel i'm going to allow hydro testing. I would do an ultrasound inspection if available near me but I'm not a knee-jerker, I don't have any gallium and I dont do destructive testing, it's just stupid.
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So you're saying you purposely refuse to do what the manufacturers and DOT requires us to do to ensure tanks are in good working order?

What exactly do you do when you "inspect" your tanks every year?
 
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That's why I trust a CF scba tank way way more than a steel or aluminum tank. Carbon fiber does not fatigue! 1 of the engineers where I worked had a MTB carbon fiber handlebars cycle tested. It was flexed way more than a handle bar would ever be on a MTB. The testing machine broke at about a million cycles but the bars were just fine. An aluminum or steel handle bar would never come close to that many cycles.
 
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DesertSilver said:
That's why I trust a CF scba tank way way more than a steel or aluminum tank.
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Properly designed steel tanks don't fatigue and can have a infinite lifespan properly cared for. I would trust them more than CF, but they are too heavy. Aluminum almost never has a infinite lifespan and will in enough cycles eventually fail. The key is to design aluminum tanks strong enough that for all practical use, the number of cycles at a given stress level never gets close the the fatigue limit. What does the curves look like for CF? I don't know, but the deep diving sub makers all use steel not CF, except for the one company in the news for a terrible fatal accident. That sub and a number of problems not only with the CF shell but using windows not rated for the pressure they were subject too. What idiot would get into the sub?

en.wikipedia.org

Fatigue limit - Wikipedia

en.wikipedia.org en.wikipedia.org

1715036472742.png
 
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F6Hawk said:
So you're saying you purposely refuse to do what the manufacturers and DOT requires us to do to ensure tanks are in good working order?

What exactly do you do when you "inspect" your tanks every year?
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DOT does NOT require anybody that is not in commerce to follow the DOT rules for for pressurized vessels.

The DOT does not require destructive testing of pressure vessels.

Carbon fiber wrapped pressure vessels will not be in good working order if subjected to destructive testing and this is the reason why they HAD a 15 max year lifespan. This is no longer the case, the USN pushed HARD for a 30 year max on CF tanks and as it turns out is solely due to environmental reasons, not due to danger, ruptures or injury.

Ultrasound is nondestructive, it's better in every way compared to destructive/hydro testing. Also, ultrasound is not testing, it is solely an inspection.

Yes, I purposely refuse to destroy my bottles and I inspect my equipement as I was trained to.
 
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If you read the Navy report on their firefighting carbon fiber bottles you will find the only mode of failure they've experienced is damage to the connections in hydro testing. So while it is not designed as a destructive test it can have that effect.

There is also no technical basis for the 5 year test recommendation or the 15 year lifetime. I'm not saying following them is a bad idea, just pointing out they are not based upon usage tests or design calculations. They were just made up when there wasn't usage data and have not been revisited.

A long time ago I got my BS in Mechanical Engineering. I agree steel is a better material from a fatigue standpoint than aluminum. I don't know about carbon fiber. In theory aluminum never has an infinite fatigue lifetime but the number of our fill cycles on our tanks is not very high from a design standpoint. So from a practical standpoint aluminum can still have a higher fatigue lifetime than we can ever achieve. The advantage I see in the carbon fiber is in the way it is applied presumably because of the low weight. Instead of making the thickness 150% or 200% of what is needed to withstand the pressure it appears from the destructive tests that the carbon fiber is much thicker than this. That extra thickness will not prevent leakage but is likely to contain any tears in the aluminum liner so they cannot get to us. I also do not think moisture will significantly degrade the carbon fiber as it can aluminum.
 
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JimD said:
If you read the Navy report on their firefighting carbon fiber bottles you will find the only mode of failure they've experienced is damage to the connections in hydro testing. So while it is not designed as a destructive test it can have that effect.

There is also no technical basis for the 5 year test recommendation or the 15 year lifetime. I'm not saying following them is a bad idea, just pointing out they are not based upon usage tests or design calculations. They were just made up when there wasn't usage data and have not been revisited.

A long time ago I got my BS in Mechanical Engineering. I agree steel is a better material from a fatigue standpoint than aluminum. I don't know about carbon fiber. In theory aluminum never has an infinite fatigue lifetime but the number of our fill cycles on our tanks is not very high from a design standpoint. So from a practical standpoint aluminum can still have a higher fatigue lifetime than we can ever achieve. The advantage I see in the carbon fiber is in the way it is applied presumably because of the low weight. Instead of making the thickness 150% or 200% of what is needed to withstand the pressure it appears from the destructive tests that the carbon fiber is much thicker than this. That extra thickness will not prevent leakage but is likely to contain any tears in the aluminum liner so they cannot get to us. I also do not think moisture will significantly degrade the carbon fiber as it can aluminum.
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I knew there was a reason I liked you, Jim! 😇

The USN has an exhaustive white paper on carbon fiber tank testing where the term "destructive'' appears several times in relation to fiber fracturing, delamination and debonding.

Simply put, the CF tanks don't expand, expansion causes defects and caused defects are destructive.

Hydro testing is an archaic method that should dissappear. It cannot find defects, it can only detect growth. Nothing more.
 
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Firewalker said:
Hydro testing is an archaic method that should dissappear. It cannot find defects, it can only detect growth. Nothing more.
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I'd clarify that statement to say that hydro testing can only detect excessive growth - it does this by pressurizing the tank to a level sufficiently above the maximum use level that it will cause growth in the first place. What they are looking for is growth outside of specifications.

Typical airgun usage of carbon fiber SCBA tanks is so far below the duty cycle of the tanks that in practice the most abusive thing that can be done to them is the hydro test itself - provided one fills the tank with appropriately dried air. Induce water vapor that leads to condensation, then all bets are off . . . .
 
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BlackICE said:
Properly designed steel tanks don't fatigue and can have a infinite lifespan properly cared for. I would trust them more than CF, but they are too heavy. Aluminum almost never has a infinite lifespan and will in enough cycles eventually fail. The key is to design aluminum tanks strong enough that for all practical use, the number of cycles at a given stress level never gets close the the fatigue limit. What does the curves look like for CF? I don't know, but the deep diving sub makers all use steel not CF, except for the one company in the news for a terrible fatal accident. That sub and a number of problems not only with the CF shell but using windows not rated for the pressure they were subject too. What idiot would get into the sub?

en.wikipedia.org

Fatigue limit - Wikipedia

en.wikipedia.org en.wikipedia.org

View attachment 462385
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Carbon fiber does not fatigue at all. Carbon fibers strength is in tension NOT compression. When that idiot made that sub to go down to the Titanic the only thing that was holding the pressure out was the resin system bonding the fibers together. I very much doubt that he used the very best of the aerospace resin systems like a BMI.
 
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AlanMcD said:
I'd clarify that statement to say that hydro testing can only detect excessive growth - it does this by pressurizing the tank to a level sufficiently above the maximum use level that it will cause growth in the first place. What they are looking for is growth outside of specifications.

Typical airgun usage of carbon fiber SCBA tanks is so far below the duty cycle of the tanks that in practice the most abusive thing that can be done to them is the hydro test itself - provided one fills the tank with appropriately dried air, Induce water vapor that leads to condensation, then all bets are off . . . .
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EXACTLY!

Any growth in a carbon fiber wrapped bottle IS destructive. There is no level at which detectable growth is acceptable.

Archaic
 
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DesertSilver said:
Carbon fiber does not fatigue at all. Carbon fibers strength is in tension NOT compression. When that idiot made that sub to go down to the Titanic the only thing that was holding the pressure out was the resin system bonding the fibers together. I very much doubt that he used the very best of the aerospace resin systems like a BMI.
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I have read he used surplus CF! Yes I know the property of CF not having almost no compressive strength. Like pushing on a string. However there can designs for using CF in such a way that external pressure puts some fibers in tension. However not an ideal use of the material.

Using windows not speced for the pressure it was subject to is enough to never put a person inside. What an idiot! Obviously he thought he was smarter than all the other engineers that he proceeded to personally use the craft.
 
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bdzjlz said:
Scary as hell for all of us that fill 4500 psi tanks. I am actually surprised we don't hear of this more often.
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Several years ago the employee at a fire department supply company told me about an accident he witnessed involving a high pressure tank. The tank rolled off his work bench and broke the valve off when it hit the concrete floor. It went through his closed overhead door and then knocked the axel out from underneath an 18 wheeler trailer parked on his lot. I took my tank home and sold it a few days later.
 
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