ISO 17769:2008 deals with terms, letter symbols and units related to the flow of liquids through rotodynamic and positive displacement liquid pumps and associated installations. It serves as a means of clarifying communications between the installation designer, manufacturer, operator and plant constructor.

ISO 17769:2008 identifies the units in common usage but all other legal units can be used.

ISO 17769:2008 deals solely with conditions described by positive values for the rate of flow and pump head. The definitions are set out showing, first, the most common form of a quantity followed by some frequently used variants. Other variants can be constructed and appropriate symbols evolved using the symbols and subscripts shown. Prefixes such as “working” and “design” can also be applied to the defined quantities.