I came across the following table for the Maximum gravitational flow through PVC or similar pipes of various sizes. believe it should be understood it is in a straight line, i.e. not accounting for any bends, and at a reasonable length, say max 10 meters, and with a pump to run the the water through the pipe like in a normal gravitational filter system.
does anyone know if this table can be used as a rule of thumb or have better information available