Depends on the piping material as Hazen Williams formula kicks in for friction losses
Approx 73,167
6
that's what she said
1200
300 gallons per minute
2.5 gallons per minute
0 gallons per minute will flow threw any pipe at 0 psi.
Depends on what is flowing through the pipe and the temperature of the pipe.
Flow = Pressure / surface S = PI * ( Diameter / 2 ) ^ 2 now you can do the math... I can't tell with gallons, inch and psi.
We need to know what pipe material will be used.
Approximately 142 gallons per minute will flow through a 4-inch pipe at 0 psi.
That's going to depend on the substance flowing and the pressure behind it. Beer -- more Molasses -- less etc.