Often the iterative procedure encountered in pipeline problems can be shortened by assuming complete turbulence in the pipe (if e/D is available) to obtain a prelim inary friction factor. This assumption is often valid for water-transmission systems because the viscosity of water is low and the velocities or pipe diameters are large, which yields high NR values. Refer to the Moody diagram and determine three to five combinations of velocities and pipe size that would produce complete turbulence at a friction factor of 0.02 (assuming water at 20°C).