Consensus on Overfilling Tanks?

[rx7diver]

I see old steel 72s dove that are older than me that have had many thousands of overfills up to 3200 psi. I don't like being near them being filled but the odds of anything untoward happening are less than being killed by a falling coconut I would imagine.

I make sure to remind anyone filling my old steel 72's (71.2 cu ft @ 2,250 + 10% = 2,475 psig) to NOT fill them beyond 2,475 psig. (My 72's all continue to be "+" rated.) In fact, I prefer to drop off these old cylinders so that they can be very slowly filled, allowed to cool, and then topped off to 2,475 psig. Some fill technicians need to be reminded that what's probably the normal setting on their fill station for filling Al 80's (say), needs to be adjusted downward for filling 72's.

However, I almost always ask for my LP OMS (Faber) cylinders to be filled so that their settled pressure is "somewhat" north of their rated pressure (= 2,400 + 10% = 2,640 psig).

And I almost always ask for my HP PST cylinders to be filled so that their settled pressure is "somewhat" north of their rated pressure (= 3,500 psig).

rx7sig

 

[Boston Breakwater]

Thank you for the chart, but better check the math. If an Al 80 holds 77 cu ft at 3000 (it does) then it cannot hold 83 @ 3100 ( < 2.7 cu ft per 100 psi is all you get)

Is it a "True 80?" LOL.....
Yeah.......No. I'm not checking the math.
This came from a well known cave diving establishment in Florida.
The amount your talking about for practical purposes is probably negligible.
...

OMG! I never knew. And to think almost every cave diver for the last 60+ years has been wrong and we should have all died since . . .

OMG! I never knew. And to think almost every cave diver for the last 60+ years has been wrong and we should have all died since . . .

That's exactly the point. I was being coy. It amazes me how many divers have blinders on, and can't read between the lines.
Cheers.

 

[tursiops]

That's exactly the point. I was being coy. It amazes me how many divers have blinders on, and can't read between the lines.
Cheers.

It amazes me how many posters can't just say what they mean rather than trying to be so damn clever and coy that their message is lost.

 

[lowviz]

I make sure to remind anyone filling my old steel 72's (71.2 cu ft @ 2,250 + 10% = 2,475 psig) to NOT fill them beyond 2,475 psig. (My 72's all continue to be "+" rated.) In fact, I prefer to drop off these old cylinders so that they can be very slowly filled, allowed to cool, and then topped off to 2,475 psig. Some fill technicians need to be reminded that what's probably the normal setting on their fill station for filling Al 80's (say), needs to be adjusted downward for filling 72's.

OK, fine that works for you. But I don't agree that steel 72's can't be filled somewhat higher on a continual and event-free basis. The numbers are there.

I own several 60's era steel 72's that were part of a very active dive shop's rental inventory. Everybody started with 80 cuft. You do the math. The tanks are fine, they always were.

Aluminum, you might have a valid argument. 72's no.

 

[wetb4igetinthewater]

Doesn't the cave community address overfills by rebuilding the valves religiously every X amount of time.

@rjack321, is that correct?

 

[Jack Hammer]

Doesn't the cave community address overfills by rebuilding the valves religiously every X amount of time.

@rjack321, is that correct?

Overfilling can seem confusing as it's done mostly on steel tanks but not on all steel tanks. Aluminum is mostly a bad idea to do. And what's considered a "safe" amount varies. On my cave tanks I'm more concerned about the extra abuse on my regs than my cylinders or valves. And my regs hold up pretty well.

 

[rjack321]

Doesn't the cave community address overfills by rebuilding the valves religiously every X amount of time.

@rjack321, is that correct?

Huh? Never heard of overfilling related to valve maintenance

 

[wetb4igetinthewater]

Huh? Never heard of overfilling related to valve maintenance

I heard/understood wrong.

So given that LP steels are (typically?) overfilled in cave country, is there anything done to mitigate any risk?

 

[Manatee Diver]

So given that LP steels are (typically?) overfilled in cave country, is there anything done to mitigate any risk?

Unless you count the water filled fill tanks, I haven't seen any procedures that are all that different except that at certain locations you don't even have to take the tanks out of your car/truck.

 

[wetb4igetinthewater]

Unless you count the water filled fill tanks, I haven't seen any procedures that are all that different except that at certain locations you don't even have to take the tanks out of your car/truck.

I don't.

Okay for the cave country divers, and I'm asking this purely out of curiosity, have there been incidents that you all know of? Not ones that make the media, as so many scuba incidents in general get buried. If there has been incidents from overfilling LP cylinders, what, if anything, is done as a practice to reduce reoccurrences?