2.5 volume beer. To gain perfect equilibrium, 12 PSIG @ 38 degrees F would prevent gas in beer from leaving solution and gas in the headspace from imparting into the top layer of beer.
For dispensing, the indusrty has utilized what is referred to as "push pressure" which equates to approx. two PSIG for keeping gas in solution as it flows through the system. With this, dispense at 14 PSIG. Will this cause flavor or overcarbonation issues? Not enough that anyone could ever detect.
Scott Zuhse, Instructor
Micro Matic Dispense Institute