THE ACCURACY AND VALIDITY OF HAZEN-WILLIAMS AND SCOBEY PIPE FRICTION FORMULAS

The authors investigate in this paper the accuracy and range of validity of both Hazen-Williams and Scobey’s formulas, the criterion being the Darcy-Weisbach formula which is the most universally accepted. A computer program is designed and used in plotting graphs for the range of validity of both Hazen-Williams and Scobey’s formulas. By means of these graphs and for a given pipe diameter, pipe roughness and permissible degree of accuracy the range of Reynolds’ number may be evaluated. In addition the authors present examples to demonstrate how to use the graphs which are found simple and practical. Generally the conclusion is that the range of validity decreases as pipe roughness increases and for rough pipes the range of validity is not much affected as pipe roughness increases