I don't understand why you'd measure the amount of a gas in volume units (e.g. cubic feet) given that any gas is "elastic" in volume, i.e. can take pretty much any volume depending on the pressure.
> Standard cubic foot (SCF) means the volume of gaseous helium occupying one cubic foot at a pressure of 14.7 psia and a temperature of 70 degrees Fahrenheit. One liter of liquid helium is equivalent to 26.63 scf of gaseous helium. One U.S. gallon of liquid helium is equivalent to 100.8 scf of gaseous helium. One pound of liquid helium is equivalent to 96.72 scf of gaseous helium. If BLM approves, you may use appropriate gaseous equivalents of volumes of helium mixtures different from these figures.
I hate it when people don't add the word "standard" to gas quantity units like this, but that is almost always what they mean. A "standard cubic foot" has the same dimension as moles; that is, it's actually a count of the number of atoms or molecules.
If it’s anything like SCUBA tanks, then the 800M cu ft is specified at 1 atm at room temperature. It’s a actually an intuitive way to express how much gas you’re getting. Specifying it by N would be borderline incomprehensible to most people.
I don't understand why you'd measure the amount of a gas in volume units (e.g. cubic feet) given that any gas is "elastic" in volume, i.e. can take pretty much any volume depending on the pressure.