Difference in bottom time between LP77 and AL80?

[H2Andy]

or even easier math

total cubic feet at rated pressure / rated pressure = cubic feet per psi

77 / 2640 = .029 cubic feet / psi

if you want to know how much the tank holds at any psi, multiply the psi by .029

so that at

500 psi it will have 14.5 cf

1000 psi = 29 cf and so on

you can use this on any cylinder so long as you know how many cubic feet it holds at its rated pressure

for cylinders that have a "+" rating, the rated pressure is the "+" pressure. for example, a 2,400+ 10% cylinder's rated pressure is 2,640

 

[ClayJar]

don't the Brits do it?

They may or may not customarily use inches, but unless I'm quite mistaken, they use a period for the decimal point as we do. Elsewhere in Europe, I've seen the comma, but those locales have never seemed to bother with non-SI units of length (of late, that is).

 

[idive2]

I'm looking at either a PST LP80 which is a hot dipped galvanized or
possibly the Worthington LP85 which I believe is hot dipped also.
I have very little first hand experience with the fills on these LP tanks.
Although one can certainly not demand an overfill, is it common to get in
the 2800-3000 range on a LP tank. My guess is that it's probably more likely
to get a 200-400 psi overfill on a 2640 than a proper fill on my 3442.