The IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam

In the 1960’s an industrial formulation for the thermodynamic properties of water and steam was developed called “The 1967 IFC Formulation for Industrial Use” (IFC-67) [1]. Since 1967 IFC-67 has been formally recognized to calculate thermodynamic properties of water and steam for any official use such as performance guarantee calculations of power cycles. In addition to this, IFC-67 has been used for innumerable other industrial applications. However, during the last few years a number of weaknesses of IFC-67 have appeared. This fact and the progress that has been achieved in mathematical methods to develop accurate equations of state led to the development of a new industrial formulation in an international research project initiated and coordinated by the International Association for the Properties of Water and Steam (IAPWS).