US/Euro SCUBA Tank Sizes

[Unregistered]

I recently returned to the US after three years of living in Beligum. I did a lot of diving and found I really liked the Steel 15L tanks in Europe.

I am trying to discover what the closest American tank in weight and pressures is relative to the Euro tanks. As I started looking on line, I discovered a great cave diving article that dealt with these differences...Aluminum VS Steel, US VS Euro, High Pressure Steel VS Low Pressure Steel. This article was a bit math intensive and involved a bit too much brain power.

Any chance of getting a great "OnlineConversion" site set-up...maybe under "Fun Stuff" or "Misc"?

[Robert Fogt]

I have added it to my to-do list.

Any chance you could provide a link to the article?

[Unregistered]

i have a US tank size X8-130; how much would this be in liters?

[JohnS]

i have a US tank size X8-130; how much would this be in liters?

US and European ratings are fundamentally different. The US rating is based on how much free air (at 1 atmosphere) the tank can hold at max rated pressure (usually 10% above working pressure). The physical internal volume of the tank (water volume) is much smaller. The European rating is based on physical or water volume.

Besides the conversion between cubic feet and liters ( 1 ft³ = 28.3 L), you need the conversion between 1 atm and rated pressure. The gas is so compressed that it doesn't strictly obey the ideal gas law, so you also need "compressibility factor" (deviation from ideal gas law) at rated pressure.

This site explains the difference and does a few typical conversions:
http://wiki.answers.com/Q/How_many_cubic_feet_in_a_12_liter_cylinder