Score of the day 6.8liter 300bar CF bottles
- Thread starter Chickenthief
- Start date
I'd hope the 15 year old car has been "babied". Still wouldn't want one because EVERY rubber piece on the car that hasn't been replaced might be dry rotted. Certainly different than an HPA tank, but you did note the analogy. How can one tell whether the "expired" tanks have been "babied" or repeatedly filled/topped? Did they have water in them and suffer internal "damage". Certainly no absolutes here and a tank that looks great INSIDE and isn't beat up externally COULD last well beyond 15 years. But my understanding is that only an internal visual inspection would be possible because most testing facilities wouldn't test the expired tank. Incorrect? Also, a buyer wouldn't be able to sell them as easily if that was needed and they COULD (possibly?) fail sooner. But I guess a brand new tank could fail on first fill as well.
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Good discussion.
I might add some value to this in some small way. I was an R&D guy in a regulated consumer products business. So I know regs and technical specification requirements and the data that should back it up. Often "standards" become developed through expediency and available data. Sometimes they don't mix... The variable here is, most companies or industries dont' perform LONG term studies. Obtaining 15 year data on a product or technology is not the norm because you often need that data to make claims on a product or meet a standard. Now, they might use accerated storage conditions to do that, but that's lends to its own questions. So what time interval makes sense for regulations development. That's often a compromise between industry and the regulatory agencies. It is negotiated. So with lack of long term data, they meet in the middle. It would be interesting to see actual "catastrophic failure" data from whatever regulatory agency (DOT?) the keeps track of such things. Then look at incident reports and find out root cause. Bet is they are very rare, but again, the regs have skewed that analysis a bit. We would need to sample those of us who are not risk averse
I think a good approach is to see what kind of services these used bottles received. Are you buying from NY or Chicag FD? Ah, no way. You know what that went through, condition is key. The Navy study above, I would argue, is a "good middle of the road" condition and usage pattern. So say, we call that average, if you buy wisely. If you buy cheap, and the condition is questionable, then expect to replace it sooner than later. If the tank looks prestine, well, then extrapoate from the Navy data into the future.
From a risk assessment standpoint, if you choose wisely you should be good to go on an expired tank, but "choose wisely" to quote a fun old movie.
I might add some value to this in some small way. I was an R&D guy in a regulated consumer products business. So I know regs and technical specification requirements and the data that should back it up. Often "standards" become developed through expediency and available data. Sometimes they don't mix... The variable here is, most companies or industries dont' perform LONG term studies. Obtaining 15 year data on a product or technology is not the norm because you often need that data to make claims on a product or meet a standard. Now, they might use accerated storage conditions to do that, but that's lends to its own questions. So what time interval makes sense for regulations development. That's often a compromise between industry and the regulatory agencies. It is negotiated. So with lack of long term data, they meet in the middle. It would be interesting to see actual "catastrophic failure" data from whatever regulatory agency (DOT?) the keeps track of such things. Then look at incident reports and find out root cause. Bet is they are very rare, but again, the regs have skewed that analysis a bit. We would need to sample those of us who are not risk averse
I think a good approach is to see what kind of services these used bottles received. Are you buying from NY or Chicag FD? Ah, no way. You know what that went through, condition is key. The Navy study above, I would argue, is a "good middle of the road" condition and usage pattern. So say, we call that average, if you buy wisely. If you buy cheap, and the condition is questionable, then expect to replace it sooner than later. If the tank looks prestine, well, then extrapoate from the Navy data into the future.
From a risk assessment standpoint, if you choose wisely you should be good to go on an expired tank, but "choose wisely" to quote a fun old movie.
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I disagree with this statement. Those tanks are typically hydro tested up to 8000 or 9000psi. Even if your tank is past the hydro date, it's never been pushed to it's limitations. Even if it's had 4500 psi stored in it for years, it hasn't been pushed to it's limitations. They eventually expire due to manufacturer liability. The manufacturer of the tank doesn't want to be liable for a tank that's over 15 years old because of the potential of stresses or abuse to the tank. I've never seen or even heard of a tank exploding in a hydro test because the tank was out of date. My CF tank is wayyyyy past the hydro date and the expiration date. That's the beauty of owning your own compressor. When dive shop won't fill it, then you fill it yourself.
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Good grief, I thought we airgunners settled this BS years ago, I came close to getting kicked off the GTA years ago fot saying 12 and 13 year olds tanks were perfectly safe. Yeah, that’s right, some idiot was going to censer me for saying ranks with 2 or three years left on their hydro were safe.
I am with Henrik on this one, using something apparently the many of you do not have on this subject that would be every day experience.
I have searched for years for a story about them failing in our sport. There are no factual stories of a single expired tank blowing up, none unless some conspiracy theory idiots are spreading them. The closest thing I found was a famous airgun stock maker, in Asia, GinB’s father , blowing himself up filling a small metal non spec or approved reservoir for his target pistol.
Think about this, was the fireman who wore that 15 year old tank your so spooked about carrying a bomb on his back during his last shift? I think not.
I have been filling expired tanks for 8 years now with my own compressors. If you want to justify buying new tanks to fill with your own compressor fine, just don’t throw in the sky is falling crap. On several occasions I went from 200 ft elevation to 5730 ft elevation to my old mountain place to make my 500,550 and 615 yard cola can video’s. The change in altitude jacked up the pressure from 4500 psi to 5300 psi, an wouldn’t know, we didn’t blow up anything except some cola cans..
Retards,
Roachcreek
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I get what you are trying to say, but I guarantee you do this every single day. There is simply no way you can be a risk-free person.
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Your far more likely to die in a car accident on your way to the range. I have read of people filling these expired scba bottles and then shooting then to try and get them to explode, all they did is whistle and at the most rupture like a banana.
As I have stated in many of these “the sky is falling”threads”, Show me the carnage caused by these expired tanks. You can’t because there is none. Scuba tanks, hell yes, they are potential shrapnel bombs if used incorrectly. When I say show me the carnage, I mean true data, not some make believe conspiracy theory.
Regards,
Roachcreek
As I have stated in many of these “the sky is falling”threads”, Show me the carnage caused by these expired tanks. You can’t because there is none. Scuba tanks, hell yes, they are potential shrapnel bombs if used incorrectly. When I say show me the carnage, I mean true data, not some make believe conspiracy theory.
Regards,
Roachcreek
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Change in altitude can’t cause significant pressure changes. It’s only about a 14.7psi difference from sea level to outer space. Temperature variation can cause a significant pressure increase. The trunk of a car can get hot on a sunny day.
I agree with you about expired tanks. If I know the complete history of a tank, and it is in good visible condition, I feel more comfortable filling it than some unexpired tanks. I just retired a beat up 8 year old cf bottle rather than test it. I no longer felt comfortable with it based solely on appearance.
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