Fanning and Moody friction factors

Piping Systems
Equivalent length key pipe components
Singularity coefficient key pipe components
Partially filled pipe
Sonic Velocity
Valves types
Valves Cv
Control valve sizing for gases
Pressure safety valves
Colebrook correlation
Churchill correlation
Velocity in pipes
Flow regimes
Orifice calculations

1. Introduction

The friction factor is used to calculate the pressure drop due to the flow of a fluid in a pipe. It represents the interaction in between the fluid and the pipe. One must be extremely careful when consulting litterature for correlations as the nature of the friction factor used in not always very well apparent.

2. Relation in between Fanning and Moody coefficient

The following relation allows to go from Moody's friction factor to Fanning :

fMoody = 4*fFanning

fMoody = Moody's friction factor

fFanning = Fanning's friction factor

Note that Moody's friction factor is sometimes called Darcy or Darcy-Weisbach friction coefficient.