Consensus on Overfilling Tanks?

[happy-diver]

These discs punched out of a 0.5 mm sheet of copper and doubled up

handle most all the pressure you are ever likely to squeeze into a tank

 

[Caveeagle]

These discs punched out of a 0.5 mm sheet of copper and doubled up

View attachment 579250

handle most all the pressure you are ever likely to squeeze into a tank

I trust the stainless disks much more. Blowing a burst disk or tank valve o-ring is the kind of failure I loose sleep over.

 

[rob.mwpropane]

3550 is going to be short. Unless those tanks are icey cold, then hey free gas!
Exactly how low are you getting them?

I dive in an open quarry. When I end the dive I'm at 15' with 500psi or more, but I'll play around for a bit and wind up at 350ish. My dive plan would change if I was in a different environment.

Im not sure that is true I would read it as allow higher psi corrected to temp but do not exceed 5/4 working presure.

I dont know what the numbers are for todays tanks but when I started it was 5psi per degree F. if your tank when filled was 130F then it is 60F above and you can fill to 300psi over teh working pressure with out legally over fillng a tank. I dont know how the + comes into play with this. I would assusme the intent is to limit to the working presure and not the + rating psi.

I agree, 5/4 max but not to exceed. From everything I've read filling to +10% (which is way less than 5/4) seems to be the way to go.

 

[michael-fisch]

I trust the stainless disks much more. Blowing a burst disk or tank valve o-ring is the kind of failure I loose sleep over.

53 Tanks with DIN Valves will soon be coming to Lake City, and none of them have a burst disk! Since my compressor is coming along with, I'll never have to get them filled elsewhere.
So much for a solution to a problem that hasn't existed since the switch away from tapered threading without O-Rings on tank necks.
Michael

 

[Johnoly]

53 Tanks with DIN Valves will soon be coming to Lake City,..

Are you doing it with 3 phase power or doing a @tbone1004 conversion solution on the compressor. Lake City isn't known for easy 3 phase availability and electric costs are not cheap with FPL.& CCEC

 

[tbone1004]

53 Tanks with DIN Valves will soon be coming to Lake City, and none of them have a burst disk! Since my compressor is coming along with, I'll never have to get them filled elsewhere.
So much for a solution to a problem that hasn't existed since the switch away from tapered threading without O-Rings on tank necks.
Michael

probably no DOT stamps either which means you won't be able to get them filled elsewhere...

 

[Bladebreaker65]

Is the reason shops won't over fill due to the liability? I know one shop that fills mine to ~ 3700 or 3800?, so they're really nice when cooled. Should I be asking for this? Is there a law or something that prevents this?

This was in the original post. All that followed was great and I learned alot, thanks everyone. I think there is one factor that also answers this part of the question. I recently set up my own compressor, Had it gone thru and fully tested by my service dealer (breathing air quality test etc..) In doing this they asked me what to set the shut off psi at. We discussed this and set point is 3400 taking in calculation the cool down gives me a consistant 3100-3200 fill. 2 tanks fill in approx 35 min. So my point at your local shop who is filling your tanks at the time ( usually a dive master to be or a helper etc.. ) they fill to compressor shut off point. so that set point is what the owner accepted as ok. This does seem to vary shop to shop. most of the short fills I have had came from high turn over quick fills with a lower set point that are just trying to get the tanks filled quick for the line of people waiting. So relax and ease up if they take there time to fill your tank. You are possibly getting a better fill that way. reaching the 3000 psi mark takes 20 min making it to the 3400 can take another 15 min on my compressor

 

[Manatee Diver]

probably no DOT stamps either which means you won't be able to get them filled elsewhere...

Wayne doesn't care.

 

[rjack321]

Is the reason shops won't over fill due to the liability? I know one shop that fills mine to ~ 3700 or 3800?, so they're really nice when cooled. Should I be asking for this? Is there a law or something that prevents this?

This was in the original post. All that followed was great and I learned alot, thanks everyone. I think there is one factor that also answers this part of the question. I recently set up my own compressor, Had it gone thru and fully tested by my service dealer (breathing air quality test etc..) In doing this they asked me what to set the shut off psi at. We discussed this and set point is 3400 taking in calculation the cool down gives me a consistant 3100-3200 fill. 2 tanks fill in approx 35 min. So my point at your local shop who is filling your tanks at the time ( usually a dive master to be or a helper etc.. ) they fill to compressor shut off point. so that set point is what the owner accepted as ok. This does seem to vary shop to shop. most of the short fills I have had came from high turn over quick fills with a lower set point that are just trying to get the tanks filled quick for the line of people waiting. So relax and ease up if they take there time to fill your tank. You are possibly getting a better fill that way. reaching the 3000 psi mark takes 20 min making it to the 3400 can take another 15 min on my compressor

Going 300-400 psi over so an AL80 cools to 3000 or 3100 is not overfilling!!!
Overfilling is pumping a 3AA 2400+psi steel cylinder to 3600.

Getting 2700 in an AL80 is a short fill. Dive shops are sloppy fill stations, they don't provide allowances for cooling and hooking up tanks twice is double the labor.

 

[rddvet]

Wayne doesn't care.

I love Wayne, but he doesn’t care about a lot of safety things. One day I worry it’s going to come back and bite him in the ass.
He didn’t get why I think he’s nuts for turning on his compressor to fill his banks, leaving to run errands for an hour or more then coming back. Though that conversation was before the CO issue. I haven’t brought it back up since.