Full fills on HP Steel Tanks

[Gombessa]

IMO the record on overfilling tanks is pretty clear, and we're not even talking about that for HP. If you're looking to get 3,442 psi in a cool tank, I'd have no problem getting a hot fill to whatever will cool down to rated pressure. The design spec, irrespective of safety factor, takes into account reasonable heat expansion, and I shouldn't have to store my tanks in the wine cellar to protect the steel.

At the same time, I get fills at a shop, and it's not my butt on the line, regardless of how minuscule I believe the risk to be. If they don't want to overfill, I don't hassle them over it (though if I really want an overfill, I'll bring the tanks to a place that'll do it).

 

[bbianchi]

True...a tank at 3700 PSI at 70F was probably filled to over 4000. Like I said if I have 3400 PSI when my tank's cool in the ocean im happy. When I have 3100 thats not so nice. The good thing about monterey is the ambient and sea temps are darn near within 10F all year long .

 

[mikeguerrero]

Ken that makes the most sense to me; if you pressure the tank to 3800 and then it cools down to 3442 psi, and the tank sits, is it really being pushed beyond it limits for long extended time?

Sounds pretty straightforward to me. I cannot believe some of the tanks I see at the shop in age and as long as they have the hydro stamp and the viz is in accordance, I fill them.

 

[dannobee]

I fill my HP tanks to 3800-3900 in order to end up with 3500 cold. FWIW

 

[David_57]

They pump my double HP 100's up to 3,700 hot but when I get in the water (cold up here in Canada) they drop to around 3,200 to 3,300 psi which = about 95 to 96 cubic feet per tank, the only down side of HP 100's as I love everything else about them.

LP 95's can be filled close to 2,800 they tend not to get as hot as HP tanks, this = approx 109 cubic feet per tank so you get a better fill, but the buoyancy properties are not as good as the HP 100's plus they are heavier.

 

[Guy Alcala]

I fill my HP tanks to 3800-3900 in order to end up with 3500 cold. FWIW

Same here, although I prefer to leave them overnight at my LDS and top them instead, which they're good about. Hot fills to 3,000 on my (2,640 PSI) LP tanks will result in 2,600-2,700 cold.

Guy

 

[dannobee]

Same here, although I prefer to leave them overnight at my LDS and top them instead, which they're good about. Hot fills to 3,000 on my (2,640 PSI) LP tanks will result in 2,600-2,700 cold.

Guy

Oh, now we're talking LP tanks. I fill those tanks to 3800-3900 in order to end up with 3500 psi when they cool off.

 

[Guy Alcala]

Oh, now we're talking LP tanks. I fill those tanks to 3800-3900 in order to end up with 3500 psi when they cool off.

I won't generally hot fill my LP tanks that high; I tend to get them to 3500 and them top them once cool. My LDS did give me a 3800 PSI fill once, when I was getting a couple of HP tanks filled as well and they apparently assumed my LP tank was one. I remember I was down for an hour or so on the dive I used it, and still had something like 1/2 a tank left.

Guy