# Hazen-Williams Head Loss due to Friction Equation

This head loss due to friction formula is used in Hazen-Williams equations.

## Hazen-Williams Head Loss due to Friction Equation formulas

\(\large{ h_f = \frac { 4.73\; l_p \; \left( \frac {Q}{C} \right) ^{1.852} }{d^{4.87} } }\) | (US units) |

\(\large{ h_f = 4.73 \left( \frac {Q}{C} \right) ^{1.852} \frac{l_p}{d^{4.87}} }\) | (US units) |

\(\large{ h_f = 10.7 \left( \frac {Q}{C} \right) ^{1.852} \frac{l_p}{d^{4.87}} }\) | (SI units) |

### Where:

\(\large{ h_f }\) = head loss due to friction

\(\large{ Q }\) = flow rate

\(\large{ C }\) = Hazen-Williams Coefficient

\(\large{ d }\) = inside diameter of pipe

\(\large{ l_p }\) = lenght of pipe

Tags: Equations for Pipe Sizing Equations for Head Equations for Hazen-Williams