The above equation is used to calculate any accurate pipe head losses.

=> h = $\frac{fL}{D}*\frac{V^2}{2g}$

where is ,

h = head loss (in ft)

f = Darcy-Weishbach fraction factor Dimension less (0.001 - 0.07 usually 0.02 - 0.03)

L = Length of the pipe (in ft)

D = Diameter of the pipe (in ft)

V = mean velocity (in $fp^3$)

g = Acceleration due to gravity ($\frac{ft^2}{s}$)