MikeFerrara:
Engineers are often wrong especially when they're doing what an MBA tells them to do. Also they usually know it's wrong when they're doing it..
Its not that they are "wrong": it is that there is always tension between the technical side and the business side for what constitutes an acceptable or unacceptable risk, which ultimately boils down to money and profits.
For an illustrative case study, current Mad Cow disease bit, in the context of the 5-year ban the USA placed on Alberta Canda for what will prove out to be a lesser QA infraction than what is being found in Washington State.
As an engineer...One of the things some engineers spend lots of time doing is argueing test specs with QA and sometimes even legal people.
Yes, this can happen when there is not clear understanding of the relevant risks, and their degree of criticality. As a fellow engineer I can say with firsthand experience that when you win the lawsuits afterwords, you are vindicated, and you have fewer arguements with the QA and Legal guys
While overfilling might cause a tank to have a shorter life (fail hydro sooner?) some might be able to accept that.
First, there is absolutely no question from an Engineering standpoint: this is classical fatigue cyclic loading, so a higher operating pressure will manifest itself as fewer load cycles (eg, "fills") at the same predetermined level of acceptable risk.
And while I agree that a shorter life may be acceptable, the problem generally found in scuba diving is that no one has any clue as to what the risk and/or revised lifespan is, becuase they've never done the formal Engineering Analysis.
At best, we have anecdotal data from Joe Nobody's who didn't do a scrap of analytical analysis, but just put maybe 1000 overfills on their tanks, and have turned around and declaired that it is enough to declare it "perfectly safe" for anyone and any application.
Finally, let's not forget that the Engineering Analysis isn't complete until it formally includes the Engineer's name, Discipline, PE licence#, State of Registration, and the document franked with his stamp and signed, because from a Professional Engineering standpoint, anything less falls short of Doing It Right. If anyone has a problems with this, they can go take it up with the ASME and NSPE.
-hh