.Flow in valves and fittings Resistance coefficient K, valves and fittings head loss and flow velocity | Pipe equivalent length L/D Pressure drop or head loss is proportional to the velocity in valves or fittings. For the most engineering practices it can be assumed that pressure drop or head loss due to flow of fluids in turbulent range through valves and fittings is proportional to square of velocity. To avoid expensive testing of every valves and every fittings that are installed on p