Pressure drop

Pressure drop is defined as the difference in total pressure between two points of a fluid carrying network. A pressure drop occurs when frictional forces, caused by the resistance to flow, act on a fluid as it flows through the tube. Pressure drop increases proportionally to the frictional shear forces within the piping network. 
There are a number of factors that impact on the degree to which pressure drop occurs in a piping system, including the following: