This diagram is based on the newest Industrial Standard IAPWS-IF97 for the Thermodynamic Properties of Water and Steam, which replaces the previous industrial formulation IFC-67.

Hans-Joachim Kretzschmar is Professor of Technical Thermodynamics at the Zittau/ Goerlitz University of Applied Sciences and specialises in the calculation of the properties for working fluids in heat cycles, boilers and turbines. The property libraries for water and steam, humid air and humid combustion gases developed by his group are used worldwide in more than 100 companies, institutions and universities. Prof. Kretzschmar is an active member of the International Association for the Properties of Water and Steam (IAPWS) and Vice Chairman of the IAPWS Working Group on "Thermophysical Properties of Water and Steam" (TPWS). As such, he was involved in the development of the industrial standard IAPWS-IF97. As chairman of the Task Group on "Supplementary Backward Equations for the Industrial Formulation IAPWS-IF97" he has coordinated the development of further backward equations for thermodynamic process modelling. His research group in Zittau developed the supplementary standards IAPWS-IF97-S01, -S03 and -S04.