In 1995, IAPWS approved a
new formulation of the thermodynamic
properties of water and steam for general and scientific use.
This replaced the 1984 formulation of Haar, Gallagher and Kell,
and now serves as the international standard for water's
thermodynamic properties.
An archival paper describing this formulation has been published:
W. Wagner and A. Pruss,
"The IAPWS Formulation 1995 for the
Thermodynamic Properties of Ordinary Water Substance for
General and Scientific Use," J. Phys. Chem. Ref. Data,
31, 387-535 (2002).
Software
implementing this formulation is available from NIST (described at this
website),
and from Prof. Dr.-Ing. W. Wagner
(described at this
website).
NIST has also provided online access to properties computed from this formulation
in the "Thermophysical Properties of Fluid Systems" section of the
NIST Chemistry Webbook,
and a
printed tabulation
of properties computed from the formulation.
The Russian National Committee of IAPWS has provided an
online calculation site for IAPWS-95 properties as a function of density and temperature.
A
compilation of experimental data
used to develop the IAPWS-95 formulation is available.
For the special requirements of the steam power industry,
IAPWS also maintains a separate
formulation for industrial use.
In 1997, IAPWS approved a new formulation of the thermodynamic
properties of water and steam for industrial use
(referred to as IAPWS-IF97), replacing the
IFC-67 formulation that is familiar to many from its use in the
1967 ASME Steam Tables.
An archival paper describing this formulation has been published:
W. Wagner et al., "The IAPWS Industrial Formulation 1997 for
the Thermodynamic Properties of Water and Steam,"
ASME J. Eng. Gas Turbines and Power,
122, 150-182 (2000).
Computer code implementing this
formulation is made available
from IAPWS national committees (the implementation by the American
Society of Mechanical Engineers is described
here;
the implementation of Prof. Dr.-Ing. W. Wagner, head of the group
that developed IAPWS-IF97, is described
here,
another group in Germany has developed software described
here and an
online property calculator,
and the Russian national committee to IAPWS has developed
software along with a
web
interface for property calculations).
Some IAPWS-IF97
software for pocket calculators
is also available, and implementations on some other platforms (mostly for student use) are described on our
Education page.
Several "Steam Tables" books based on the IAPWS-IF97 formulation for industrial use have been published. The book published in Germany is described here. The ASME in the United states has published both a full-sized steam tables book and a shorter compact booklet of steam tables. A book has also been published by the JSME in Japan, and books have been published in Russia and the Czech Republic.
Documents giving a complete description of the formulation are available for both the Formulation for General and Scientific Use and the IAPWS-IF97 Industrial Formulation.
Updated July 6, 2018