What pressure would you fill a pair of AL80s to?

[deepairmike]

Can someone explain this to me? It was my understanding that most (if not all) firefighter's gas/air tanks were made out of some material OTHER THAN aluminun. Fiberglass, maybe? Anyway, something with a limited cycle life. So I am not clear what they have to do with the question at hand.... Neither steel nor aluminum tanks "expire" after 15 years, I understood that the fiberglass (?) tanks do... These are fundamentally different types of tanks, no?

They weren't always composite tanks. Some rural fire departments can't afford composite tanks and still use alum tanks.

[firemedic1015]

The solid AL tanks don't have a limited service life. It's the fiberglass or carbon hoop wrapped aluminum composites (three year retest interval) and the modern carbon fiber cylinders (five year retest interval) that have a 15 year service life.

[lv2dive]

So do the aluminum ones still have to be discarded after 15 years?

The solid AL tanks don't have a limited service life. It's the fiberglass or carbon hoop wrapped aluminum composites (three year retest interval) and the modern carbon fiber cylinders (five year retest interval) that have a 15 year service life.

[firemedic1015]

Not the solid aluminum ones.

[mfascuba]

I'm conservative with aluminum cylinders, I'll go a hundred or two over 3000 while filling but not much more than that. Steel on the other hand, "what do you want?", is met with my reply "as high as your banks & compressor can do".

[JCGoodwin]

I like to fill AL 80's to 3000 psi let them cool overnight then top them to 3000.
In a perfect world you always have the option.
I do not push AL cylinders it just is not worth the stress on the tank.
STEEL? Well depends on the diving.
In Cave Country 3600+
Deco dives 3600+
Quarry dives 3200-3400 routinely

+translates rarely beyond 3800.
I do not like hot fills always like to take time to keep the heat down.

JCG

[Nitrogenius]

Hydrotesting, by definition, is a DESTRUCTIVE testing procedure.

Yes. It is a destructive testing procedure by defintion, because if it Fails the test it is destroyed, thus the test is done in a confied compartment..

The act of Hydrotesting causes damage to the Al tank.

No, sir, I disagree. It causes extra and exceptional high stress on the tanks. All materials have a limited stress-release-hysterisis lifespans and thus such test (and a fill Close to test pressure) does have an Impact on the lifespan.. But it is not damage as such..

The tank IS designed to tolerate a LIMITED amount of hydrotesting during it's lifespan. Not every day!

All tank materials tolerate a limited amount of stress-release cycles.. so does Aluminium.. Stell just tolerates a bit more cycles.. the mechnic as such though does not Change and higher stress always Impacts the possible cycle numbers..


Nobody had been saying anything about everyday.. I just oposed the Statement that overfilling to a range of 3900 PSI is stupid!
It certaintly isn't without danger and should, if at all only be done by someone knowing their stuff..
But it is not Stupid per se!

[Jack Hammer]

...Nobody had been saying anything about everyday.. I just oposed the Statement that overfilling to a range of 3900 PSI is stupid!
It certaintly isn't without danger and should, if at all only be done by someone knowing their stuff..
But it is not Stupid per se!

Regardless of semantics or however you wanna try and spin it, I think most people would agree filling aluminum tanks to 3900psi isn't wise.

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[cerich]

if a tank fails during hydro, nobody dies. If during filling, maiming and death almost always.

I respect the people filling my tanks too much to hand them alum tanks to fill that I know have been potentially compromised by repeated filling beyond the rated pressure. I have failed too many tanks, seen to many that have failed during filling and know personally two people that died when filling them. The process of filling the tank is much more cumulative damage with aluminum than with steel. That's science, not speculation. So I am very conservative.

[Nitrogenius]

So I am very conservative.

And that is ok to be.. So am I.. Nevertheless someone not being as conservative filling up to 3900 once for a Special purpose is not necesarily stupid..
I would just get the right tank for the Job instead, but that is another Story..