In the linked PDF (
http://www.phmsa.dot.gov/staticfile...ecall_Order_The_Lite_Cylinder_Company_Inc.pdf) starting on page 5, they state that a number of people were hurt at their manufacturing facility in the Dominican Republic, and that there have been failures in the field as well.
Mitch, thanks for the PDF, that is great info, and makes me feel much better about keeping mine and continuing to use it (esp since we are not going to get compensated for it). This is my rational (Now this would never fly where I work, FAA and gov would fry us, bankrupt us and most of us would be in jail for the kinds of unethical practice exhibited by them), but from a practical point of view, for the cylinder that is currently mounted in my truck, I am ok with is as based on the following (other ppl views may vary, this is MY view):
The claims they state in the pdf:
1. Failure to notify of failure – Don’t really care, this is a paperwork issue, they have VALID Failure rate data defined further down.
2. Failed to stop selling – Again, don’t care, will cause no personal injury to me.
3. Failed to test at 480 psi for an operating pressure of 320 psi – Now we get into the meat that I care about (as a test engineer). So lets see, the operating pressure is 320 psi, the required test level is 480 psi meaning a margin of safety of 1.5 (50% higher test level than max operating pressure - this is very typical ..in my field its refered to as "max operating" = 320 and "limi"t = 480...limit is usually ALWAYS 1.5 of max operating). Now they failed to do this, however it was confirmed that they DID test to 441 psi, so that is a FS of 1.38 (38% higher than max operating pressure).
This is up to individual opinion, but I personally am ok accepting a FS of 1.38 myself. THIS IS KEY.
4. Conducted burst using first of each lot rather than random sample – This is more of a formality as well. We do this a lot here in aerospace, required random sampling, etc. at the end of the day they DID test units from each lot, the only difference is they took the first of each lot. The concern here is if they build those test units with more “attention to detail” because they knew they were being tested. Random sampling would make this impossible. I do agree that this is possible, they may have made a special build for the test samples, however, in my experience, this is normally not the case, We have had numerous suppliers that have done the same thing (didn’t do random and accidently did set number from lots). At the end of the day, I have never seen this occurs because the supplier was being shady, they just didn’t understand the requirement.
Now it is possible they were being shady here, but Burst is a VERY worst case possible test (Catastrphic failure test). If I am in a condition where I have exceeded max operating pressure and limit load (remember they already PROVED to have a FS of 1.38), something else is majorly wrong, and even if they did test to a burst pressure, say 750 psi (for example) or whatever the requirement is, there is no guarantee that the pressure will not exceed that. Burst testing is more of a formality to test the limits of when it WILL fail...and well, if it does fail in my truck, nomatter what pressure, I'm pretty much SOL. Burst is really a “we have to do it, but it doesn’t really mean anything in real life because when you get there, its too late” test.
5. Failed to manufacture to their quality control document - Well that sucks a lot, but in my opinion, at the end of the day, no matter what little quality control things they did not follow, if it passes ATP, then it still functions as designed. And again, they ARE tested to a FS of 1.38…so I am ok if they didn’t have their grinding wheel adjusted correctly during manufacturing, as long as it pasts real life testing AFTER manufacturing.
6. Failure to notify – Again Paperwork, not gonna blow up due to this.
7 Failure to properly label – Paperwork, not gonna blow up due to this.
The example at the end they give when they tested 1148 and had 53 leak (Failure Rate of 4.6% is even more validation that I am ok keeping mine. This failure rate is based on the REAL required test pressure of 480, so basically, what this tells me is the following:
1148 passed testing with 441 psi (FS of 1.38) – 100% of Test Samples
1095 passed testing with 480 psi (FS of 1.5) – 95.4% of Test Samples
Now I can pull out probabilities and statistics and get REAL values, but I think its safe to assume that anyone can see that the odds of my unit meeting a FS of 1.38 is 100% (as that is what they ATP them too), the odds of it meeting a FS of 1.5 is approximately 95%. And remember, I don’t even care if it meets the 1.5 FS, Personally I’m ok with the 1.38.
All that being said, if my truck ever does blow up due to the cylinder, I give you all permission to say "I told you so"
