# Kv (Flow Coefficient)

A Kv value is sometimes used to express the pressure loss relationship as a function of flow. There are many types of equipment items and pipe fittings that can be described by Kv values. To use this type of loss element you must know a pressure loss for a given flow across that element. Often this data can be obtained from a manufacturer. It is possible to enter this type of fitting into the FluidFlow database, but FluidFlow does not force you to work in this way as it is also possible to add/change a Kv value directly (or rather the reference conditions) via the Input Editor.