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Re:Tanks Overfils Michel Wrote: Did anyone made serious research on this? To which extent is it safe or unsafe to overfill steel, low pressure, scuba tanks? Thank you in advance. Michel Therrien ********************************************************************** Safe? well in print we will have to say the DOT rated pressure. If you pass this number you may end up in the "Twilight zone". It all comes down to a risk factor, If we perceive a risk factor to be high, we will usually back off. (read "Exley's Razor" in the last issue of Underwater Speleology) In Florida where I do most of my cave diving, the risk factor in relation to overfilling is perceived as low. Chris Brown put it well the other day in a post.(not as per quote) Do we outlaw bike riding on the streets due to the HIGH death rate? No we don't. Should we outlaw cave diving due to a high perceived risk factor? It sounds like some government officials are going in this direction. Do we close down our shops for over filling scuba tanks, I don't think so. In the eight years I have been cave diving I have had my 104's pumped to 3500-4000 psi! My 95's to 3300-3500 psi! Yes, they all have passed hydro. Yes, some are plugged and some have two disk. Yes, all the shops I go to will give me these fills. WHY? Lets look at how many fills in the cave diving community are pumped per year. Exact figure not known, but it's in the hundreds of thousands. Then look at the risk factor. How many have been killed due to the direct over filling of these tanks. (I am referring to the cave diving community, not the South Florida salt water rec. diving) I think "0". In my shop the hydro man locked up for the night during an active hydro. ( He no longer works for a dive shop!) The alum. 80 burst at 12000+ It left a 8" split in the side of the tank. The back pressure of the water blew out my test tubes and the glass plates in the gauges. (the customer got a new tank) The US Navy did a test in the 70's on the PST 104's (I had a bootlegged copy of this test but lost it, so take this for what it's worth) In the underground test site near Jackass Flats Nevada the Navy took both new and used 104's for this test. NO hydro was used, the average failure fell over the 18,500 psi mark! Will a manifold hold up to this, I don't think so. So from now on this thread will be called "How safe is it to over fill a manifold". I am 49 years old, my risk factor is that of a heart attack lifting those bastard doubles off the ground! Best to you all, Ed Edward P. Stoner Denise M. Stoner carstair@ix*.ne*.co* carstairs@ao*.co* Orlando, FL USA April 13, 1995 11:17 am
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