fmw625
Guest
Been a long time since I worked with this stuff. Using Deg K or Deg R , the pressure works out to about 112% @ 70 Deg F. This seems to be very close to a +10 fill
Help Validate Facts on Overfill to LDS
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lamont
Contributor
jonnythan:
a few hundred psi overpressurization is not going to cause the tank to fail. it definitely won't fail violently in an explosion. it will either fail hydro, fail vip or start to leak. most likely a vip will turn up rust and get it first, which has nothing to do with overpressurization.
And the people who regularly fill the 2400 psi tanks to 4000 psi?lamont:
That's not a few hundred..
Charlie99
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And the people that regularly go to 160' on air ?? Just because you "get away" with something doesn't mean it's a good idea.jonnythan:
People have actually died doing that. AFAIK no modern steel tanks have failed as a result of overpressurization.Charlie99:
Applying a little common sense...which isn't so common...filling a little high hot isn't an overfill. If you only go a couple hundred over it may still cool a little low. Joels suggest is probably the best but I've never seen such a setup.
With regard to real overfills like cave fills, lots of us do it but I'd never expect (or even ask) a shop to do it though some do (especially in cave country). The new PST tanks solve the problem rather well making a cave fill just a regular fill and legal to boot (even in a dive shop).
With regard to real overfills like cave fills, lots of us do it but I'd never expect (or even ask) a shop to do it though some do (especially in cave country). The new PST tanks solve the problem rather well making a cave fill just a regular fill and legal to boot (even in a dive shop).
lamont
Contributor
jonnythan:
well, you've got those three tanks tested to destruction with 10,000+ fill cycles at 3600 psi. you're above that pressure, but not by much.
you will get faster cracking. steel still cracks slowly. you should see a higher rate of hydro failures in LP tanks.
even if they do fail, they should still leak-before-burst. they're still designed to LBB at 4000psi.
since we don't see a rash of overpressurized LP steels leaking and failing hydro coming out of cave country it seems pretty safe. to make it safer, hydro more frequently. hydro is proof that the tank doesn't have any large cracks and it takes time for the large cracks to form, so you're good for awhile after hydro.
DepthCharge
Contributor
NutJob:
I still don't buy it. The bands are a much softer and thinner metal. If the the tank "bulged", then the bands would have stretched also.
nauidiver2004
Guest
DepthCharge:
True, the bands would have also streached but the cylinder wall would still have deformed around the band. If you don't believe that, then explain how a water jet machiene can cut through plate steel
I walked in to a diveshop to pick up fins one day, and the owner of the shop was overfilling some tanks. Well the burst disc failed on one of them and the neck popped off. This thing took off like a missle through the roof and nearly took me with it. Take it from someone who has seen these things pop: You don't want to do this.
The same diveshop has tried to kill me a few times since then. It may not be the tanks, but the poor care they have recieved. This shop is The Aquatic Center in Gainesville, Florida. Please avoid at all costs.
Thanks,
-V
The same diveshop has tried to kill me a few times since then. It may not be the tanks, but the poor care they have recieved. This shop is The Aquatic Center in Gainesville, Florida. Please avoid at all costs.
Thanks,
-V
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