Assessment of Pressure The pressure losses for distribution in the GF Piping Systems can be assessed by means of the following chart or by means of the following formula: Where: pressure loss in a straight pipe (bar) A pipe friction factor (in most cases 0.02 is sufficient) length of straight pipe (m) density of transported media (kg/m3) flow velocity (m/s) inside diameter of pipe (mm) Loss Pressure Diagram for PN20 / PN28 Pipe 32 AQUASYSTEM PP-R | Strong Veins for Your Building Assessment of Pressure Loss Pressure Diagram for PN10 / PN14 Pipe 33 AQUASYSTEM PP-R | Strong Veins for Your Building