IAPWS Releases, Supplementary Releases, Guidelines, and Advisory Notes
IAPWS provides recommended formulations for numerous properties of water, steam, and aqueous solutions. These fall in several categories:
- Releases provide carefully evaluated, internationally agreed-upon data and formulations of properties for which measurements of high quality exist over a wide range of states. They are intended to embody the state of the art for representation of the property at the time of the Release.
- Supplementary Releases provide supplementary material to an existing Release, or provide specific (perhaps simpler) formulations for a subset of the material in an existing Release. They are intended to be of the same quality as Releases.
- Guidelines are similar, but for properties where the quality or range of the available data is limited. They are therefore not expected to provide as definitive a representation as Releases. Guidelines are expected to require revision when new information is available.
- Advisory Notes are documents that give additional information and guidance that is intended to be useful for users of IAPWS property formulations.
A different type of IAPWS document is the IAPWS Certified Research Need (ICRN), which is a statement of the need for research on a specific topic. ICRNs are listed on a separate page.
An additional type of IAPWS document is the IAPWS Technical Guidance Document, giving international consensus guidelines on cycle chemistry for fossil and combined cycle power plants. Technical Guidance Documents are listed on a separate page.
All current IAPWS Releases, Supplementary Releases, Guidelines, and Advisory Notes are listed below and are downloadable as PDF files.
While IAPWS does not produce software, many IAPWS formulations have been implemented in software produced under the authority of the National Committees of IAPWS member countries; this page has links to these sources.
A separate document is available describing obsolete IAPWS recommendations that were issued in the past but are no longer current.
Releases
(September 2011) (This is a minor revision of the 2008 release, which replaced the corresponding release of 1993)
R11-24: Revised Release on the Ionization Constant of H2O
(June 2024) (This is a revision of the 2007 release)
R10-06(2009): Revised Release on the Equation of State 2006 for H2O Ice Ih
(September 2009) (This is a minor revision of the 2006 release)
(September 1997) (This release replaces the corresponding release of 1991)
(September 1997) (This release replaces the corresponding release of 1977)
(The revision only relates to the extension of region 5 to 50 MPa) (August 2007) (This is a revision of the 1997 release, which replaced the corresponding release of 1967). NOTE: This release has been supplemented by additional "backward" equations for p(h,s) in Regions 1 and 2, T(p,h), v(p,h), T(p,s), v(p,s) in Region 3, p(h,s) in Region 3 with auxiliary equations for independent variables h and s, and v(p,T) in Region 3.
(September 2018) (This is a minor revision of the 1995 release, which replaced the corresponding release of 1984)
R5-85(1994): Release on Surface Tension of Heavy Water Substance
(September 1994) (This is a revision of the 1985 Release)
(September 1992) (This is a revision of the 1983 Release)
R1-76(2014): Revised Release on the Surface Tension of Ordinary Water Substance
(June 2014) (This is a minor revision of the 1994 revision of the 1976 Release)
Supplementary Releases
SR6-08(2011): Revised Supplementary Release on Properties of Liquid Water at 0.1 MPa
(September 2011) (This is a revision of the 2008 Supplementary Release)
(June 2014) (This is a revision of the 2005 Supplementary Release). NOTE: This Supplementary Release provides additional "backward" equations designed to accompany the IAPWS Industrial Formulation 1997
(June 2014) (This is a revision of the 2004 Supplementary Release). NOTE: This Supplementary Release provides additional "backward" equations designed to accompany the IAPWS Industrial Formulation 1997
(June 2014) (This is a revision of the 2004 Revised Supplementary Release). NOTE: This Supplementary Release provides additional "backward" equations designed to accompany the IAPWS Industrial Formulation 1997
(June 2014) (This is a revision of the 2001 Supplementary Release). NOTE: This Supplementary Release provides additional "backward" equations designed to accompany the IAPWS Industrial Formulation 1997
SR1-86(1992): Revised Supplementary Release on Saturation Properties of Ordinary Water Substance
(September 1992) (This is a revision of the 1986 Supplementary Release)
Guidelines
G14-19: Guideline on the Surface Tension of Seawater
(October 2019)
(September 2004) (This guideline replaces a gas solubility guideline issued in 1993 and a distribution constant guideline issued in 1998.)
G5-01(2020): Guideline on the Use of Fundamental Physical Constants and Basic Constants of Water
(September 2001). NOTE: This Guideline is reviewed annually and updated as necessary. Latest update September 2020.
G3-00(2012): Revised Guideline on the Critical Locus of Aqueous Solutions of Sodium Chloride
(October 2012) (This is a revision of the 2000 Guideline)
(September 1994) (This is a revision of the 1990 Guideline)
Advisory Notes
AN3-07(2018): Revised Advisory Note No. 3: Thermodynamic Derivatives from IAPWS Formulations
(September 2018) (This is a revision of the 2007 Advisory Note)
(September 2004). NOTE: This Advisory Note is reviewed annually and updated as necessary. Latest update September 2013.
Uncertainties in Enthalpy for the IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use (IAPWS-95) and the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam (IAPWS-IF97)
(August 2003)
