Cuft to liter conversion

[mania]

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A ScubaBoard Staff Message...

Please refrain from bashing each other.

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[rongoodman]

There's a metric conversion chart for the Worthington cylinders on the XS Scuba site. I just remember that my LP85s are a little less than 13 liters and the HP 130s are 16.

 

[Tassie_Rohan]

My God! Yet one more thread rises from the crypt!

I know this is International Restart Old Thread Week, but a post from 2001????


Seriously - are the warnings about 'this thread has had no posts for X years' still turned on when people try to restart long dead threads?

 

[El Orans]

Seriously - are the warnings about 'this thread has had no posts for X years' still turned on when people try to restart long dead threads?

Oh, it's still there.

 

[NudeDiver]

So....do you want to say that in 2009, people should no longer care about cf to L conversion?

 

[Tassie_Rohan]

No.

In the year 2009 people should not care about any imperial units of measurement: feet, yards, chains, bull-roars and other such historical oddities.

America - the Stone Age called: they want their measurement system back...

 

[300bar]

:lol:

 

[Packhorse]

There are 28.3 litres per cubic foot.

To find out how many litres of air a "metric tank" holds multiply its size or WC by its pressure in bar.

So a 12 litre tank X 200 bar = 2400litres. 2400/ 28.3 = 84.8 CF. Note: this is how much air is in the tank which is much more important than how much air the tank CAN hold IMHO.

If you want to know its rated contents then its size ( WC) X WP or CP (Working pressure/Contents Pressure). So 12L x 232bar / 28.3 = 98.4 CF

 

[evil_xander]

There are 28.3 litres per cubic foot.

To find out how many litres of air a "metric tank" holds multiply its size or WC by its pressure in bar.

So a 12 litre tank X 200 bar = 2400litres. 2400/ 28.3 = 84.8 CF. Note: this is how much air is in the tank which is much more important than how much air the tank CAN hold IMHO.

If you want to know its rated contents then its size ( WC) X WP or CP (Working pressure/Contents Pressure). So 12L x 232bar / 28.3 = 98.4 CF

So by simply filling my 2x12 to 200 or 232 bar I can dive either 2x85 or 2x98 CF tanks. Nominally, they are 232 bar, but it's cool they strech depending on occasion.

Imperial system is fun.:cool2:

 

[Pearldiver07]

I know Rick knows this,
And Ed I wonder if you were sleeping in your basic scuba classes.

The internal volume of a tank is usually expressed in liters. The internal volume of a tank will not change with pressure. So the ft^3 rating you see is the amount of free air delivered at 1 atmosphere. e.g. A Luxfer Al80 has an internal volume of 11.11 liters. When filled to 3000 psig it will deliver 77.4 cubic feet of air at one atmosphere. The volume of the tank is 11.11 L at 14.7 psia and is 11.11 at 3000 psig (neglecting the deformation of the metal under stress). You can determine this with the appropriate gas law relationships. For a straight conversion of metric units to imperial units the liter is 0.03531467 ft^3.

I approach it a slightly simpler way, using units to ensure I get to the right place. Although I didn't work it backward. It will allow you to convert a "liter" tank to a "cuft" tank for any given pressure by replacing the individual values:


If, 11.11 liters = 0.39235 cuft (it does; 1 liter = 0.0353146667 cubic feet, so 11.11 times .0343146667), and 3,000 psig = 204.1 atm ( in mathematical terms: 3,000psi/14.7psi per atm)


then, 204.7 atm/tank* .39234 cuft = 80 cuft/tank.

Take any size of tank in liters, and complete the math for the desired working pressure. It will work.