Question Subsurface sac unit
- Thread starter Mario007
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No. They wanted something that can be compared across cylinders of different sizes.
SAC is litres/min, i.e. volume of gas at surface pressure (1ATA) per minute.
Volume of gas converted into a pressure drop needs to factor in cylinder volumes.
To convert SAC (as litres/min) to pressure drop, just divide the SAC by the wet volume of the cylinder.
E.g. SAC of 22 litres/min using an ali80 (wet volume of 11 litres) is
SAC / wet volume = 22 / 11 = 2 Bar
drakcheslav
Contributor
As said, it's literally 15 litres!
In Europe we refer to tanks as their wet volume, meaning if you filled it with water and poured it out it would, in that case, be 15 litres of water.
In the US they use another system which is the volume of gas that the tank would contain if filled to its working pressure. For example an "aluminium 80" is a tank that contains 80 cubic feet of gas at its working pressure of 207 bar (= 3000 Pounds per square inch).
For the wet volume, divide the volume (80CF) by the working pressure in Bar (207) to get Cubic Feet at 1 Bar, then convert that into litres...
80 / 207 = 0.38461538 cubic feet = 10.94371 litres ( which is 11 litres )
It is so much easier to use bar, litres and wet volume. The US system is fiddly and much harder!
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