# Liquid Pressure Loss Calculations

For calculating liquid friction losses in a physical pipe of any material, we use the Darcy Weisbach equation and the Colebrook-White formula for calculating friction factor. It is possible to configure the software to use other methods such as Hazen-Williams or Shell-MIT. The Shell-MIT method is used in the calculation of pressure loss in heavy crude oil and heated liquid pipelines and should be used for such specific cases. It is not recommended that users use this method for substances other than that described herein. The Hazen-Williams method for predicting friction loss is useful for designing fire protection and irrigation systems. It is not recommended that users use this method for substances other than water. Overall fire sprinkler system design guidelines are provided by the National Fire Protection Association (NFPA) 13, (NFPA) 13D, and (NFPA) 13R. Pressure losses through sprinklers can use the K method or the user can enter data directly from a specific manufacturer. For the calculation of pressure losses through bends, tee and cross junction the user can select from one of four available relationships: ▪Using relationships and data found in the Handbook of Hydraulic Resistance - 3rd Ed - I.E. Idelchik. ▪Using relationships and data found in Internal Flow Systems - 2nd Ed - D.S. Miller. ▪Using relationships and data found in Flow of Fluids through Valves Fittings and Pipe - Crane Technical Paper 410. ▪Using relationships and data found in AIR1168/1 - Thermodynamics of Incompressible and Compressible Fluid Flow. Performance data for centrifugal pumps, positive displacement pumps are usually taken from manufacturers data. We have developed utility software that can read and convert data directly from manufacturers catalogs. Pressure Losses through valves can be calculated from generic relationships found in the Miller and Idelchik references above. Additionally the software can use relationships based on Cv or Kv values which the user can enter. Pressure losses through check valves use the K method.