AL80 Overfilled

[chrpai]

I have 2 AL 80's (Luxfer 1999ish) that I dropped off on Monday. Today I picked them up and they both show 3800 PSI! :shocked2:

Should I bleed them down? Is the damage (if any) already done? I'm all for cave filling LP steels but not AL's.

My tanks are DIN (Pro Valves) that are clearly marked 3000PSI same as the crown markings on the tanks.

 

[KD8NPB]

They'll be fine. They're rated to cycle up to 5000 psi several thousand times. This of course assumes that your tanks are in good condition with no defects.

Enjoy your "compact size" aluminum 100.

For high pressure gas cylinders, I believe the safety factor is usually 3:1?

 

[oldschoolto]

I'd bleed them down to 3300/3200 just to be safe.... Don't think that they were hurt... The longer they stay the more likely to cause trouble at the next hydro... But I'm not a expert...

Jim...
edited to add
See, I don't know....:shocked2:

 

[T. Bix]

Chrp, Bleed them down by diving them.

 

[spectrum]

Go for 2 nice long dives and be done with it.

There is a gain of truth to not leaving term that way long term. Even though they are not the "bad" Luxfurs aluminum in general is still susceptible to sustained load stresses.

Pete

 

[3D diver]

I had a local shop do that a few times. The tank was no worse for the wear but my high pressure SPG hose failed...in the water!

 

[Doc Harry]

They're rated to cycle up to 5000 psi several thousand times.

Hogwash. Fantasy.

The rated pressure is stamped on the cylinder - 3,000 p.s.i.

Luxfer advertises that their aluminum scuba cylinders have been test-cycled 100,000 times to the rated filled pressure - 3,000 p.s.i.

 

[ianr33]

Don't leave them in the sun. (Voice of experience! )

 

[Capt.Gene]

Take them back to the dive shop that filled them and set them in the sun in the front window.

 

[DA Aquamaster]

3AL tanks are tested to either 10,000 cycles to the test pressure (5/3rds the service pressure - 5000 psi for a 3000 psi tank) or 100,000 cycles to the service pressure. Luxfer describes the pulsation test requirement and states:

"In the pulsation test the cylinders are filled with water and then cycled between test pressure and zero pressure for 10,000 cycles. The frequency is around 12 cycles per minute. This is a metal fatigue test that requires the cylinder to not leak or show signs of failure during the test. The US DOT allows 100,000 cycles between service pressure and zero as an alternative test."

Burst pressure for a 3AL Luxfer tank is usually between 2.4 and 2.6 times the service pressure (7200 to 7800 psi).

The burst disc assembly installed in the valve is designed to go at between 4500 and 5000 psi. It's still holding, so I'd dive the tanks, but the over fill may have shortened it's service life as they get weaker with age, cycles and overfills.

Consequently, while I would not leave the tank at 3800 psi all winter, I would not worry about leaving it at 3800 psi until I went diving in the near future. Any reduction in fatigue life that's occurred, occurred when it was filled.