What pressure would you fill a pair of AL80s to?

[cerich]

on a exploration type dive if I must die I would prefer it happen on the dive, not while filling a stupid scuba tank where I could possibly kill and injure others.... Filling a alm 80 to 3900 psi is bone dead stupid

I don't think Jon is looking for how high do you fill so that it cools to 3000... I think he's looking for more of a how high would you fill it to go on a dive, particularly an exploration type dive. It might be hard to get an honest answer on an open forum but "rumor has it" that in the circumstances described, 3900 shouldn't be a problem.

[JohnAd]

I'm going to go out on a limb and guess that the overwhelming majority of responders advocate keeping AL 80 tanks close to their rated pressures while feeling fine with overfilling LP steel tanks. I'm in that camp myself. I therefore found the approach of a shop I used this winter in south Florida interesting.

The shop was near where I was staying for more than a month, so I happily purchased a fill card, using it for both my LP 108 doubles and my LP 85 singles. It took a while first for me to convince them that it was OK to fill them the 10% beyond the 2400 PSI allowed by the + rating. I did eventually get them to risk going all the way to 3,000 PSI. Then I had friends join me there so I could certify them for AOW. We used the same shop, and they rented AL 80s for the dive. They were all filled routinely to between 3,400-3,500 PSI. I asked them why their policies were the opposite of most thinking, and the people doing the fills really didn't know.

[amphipod06]

They were all filled routinely to between 3,400-3,500 PSI. I asked them why their policies were the opposite of most thinking, and the people doing the fills really didn't know.

and that is why buying used AL tanks is mostly a crapshoot unless you really know the person who owned and took care of them...just my 2 psi.

Dive safe,

Celia

[Sludge]

the overwhelming majority of responders advocate keeping AL 80 tanks close to their rated pressures while feeling fine with overfilling LP steel tanks...
... AL 80s for the dive. They were all filled routinely to between 3,400-3,500 PSI. I asked them why their policies were the opposite of most thinking, and the people doing the fills really didn't know.

I'm 200 miles away from the two compressors I have used for almost twenty years, so I decided to scope out the shops in PCB to see if anybody would do cave fills (for my open water LP-95s). One shop will take them "all the way to 2600," while they take AL-80s to 3500 without batting an eye.

[OFG-1]

Depends on the dive. If they are going to be stored in the garage, then 3000 cool, if we are jumping in the water that day, 3500, warm.

OK, how much do you guys fill your steel 72's ?

[FW]

...OK, how much do you guys fill your steel 72's ?

Today, or 40 years ago?

[Nitrogenius]

Filling a alm 80 to 3900 psi is bone dead stupid

And why would it be bone dead stupid ?


They have a 3000 PSI Rating..
Filling to 3900 therefore equals filling to 130% of the reated pressure.


At DOT hydro procedures (not sure which applies for Alis) they are at least tested to 143%, 150% or even 166%..
Either one giving still additional margin towards the maximum test pressure being applied to the tank regularily during hydro testing at least..


In Germany it is generally 150% and all Ali tanks are US manufactured.. so there should not be a difference also..


So as long as one does not make this to a ususal Habit but does this for infrequent occasional purpose based use (as it is indicated by the Poll description as well) I completely can not follow whay this should be "bone dead stupid" !


Due to the fatigue issues described in the thread I personally do not like overfilling my Ali tanks, so I just overfill about 10% in order to get to rated pressure once the tank has cooled down and I oftenly overfill almost all steel tanks (other than those with a conic valve) at around 20-30%..
But stupid ????

[gschaut]

At DOT hydro procedures (not sure which applies for Alis) they are at least tested to 143%, 150% or even 166%..
Either one giving still additional margin towards the maximum test pressure being applied to the tank regularily during hydro testing at least..

Hydrotesting, by definition, is a DESTRUCTIVE testing procedure. The act of Hydrotesting causes damage to the Al tank. The tank IS designed to tolerate a LIMITED amount of hydrotesting during it's lifespan. Not every day!

In the fire service we are allowed to hydrotest Al based tanks NO MORE than five times (hydro at 3 yr intervals). At age 15 years, the tanks is retired and destroyed no matter how good shape it's in. If a tank requires extra hydrotests (service damage/repairs) during it's life span, it is retired before the 6th hydrotest is required.

[lv2dive]

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?

Hydrotesting, by definition, is a DESTRUCTIVE testing procedure. The act of Hydrotesting causes damage to the Al tank. The tank IS designed to tolerate a LIMITED amount of hydrotesting during it's lifespan. Not every day!

In the fire service we are allowed to hydrotest Al based tanks NO MORE than five times (hydro at 3 yr intervals). At age 15 years, the tanks is retired and destroyed no matter how good shape it's in. If a tank requires extra hydrotests (service damage/repairs) during it's life span, it is retired before the 6th hydrotest is required.

[lv2dive]

For clarification... I generally aim for my aluminum tanks to be at 3000 when cool... 😊... I just wasn't sure what a different type of tank had to do with it?