Java IF97

Java IF97 library

IAPWS-IF97 is the Industrial Formulation by The International Association for the Properties of Water and Steam ( This implementation is according Wagner, Wolfgang & Kretzschmar, Hans-Joachim, 2008, International Steam Tables — Properties of Water and Steam Based on the Industrial Formulation IAPWS-IF97, 2nd Edition, Springer-Verlag, Berlin Heidelberg, ISBN 978-3-540-21419-9.

This library is made available to the public domain, under GNU Lesser General Public License. That is, free for any product to use and redistribute. This library can also be included in proprietary software.

Stay informed via the IF97 mailing list → Name: Email:
Download IF97 Latest Maven IF97 artifact

IF97 project binaries and source code are hosted on SourceForge: as well as compiled sources and API documentation (javadoc).

Our IF97 library is developed in Java, with a test suite containing a mere 100 tests readily available in the source distribution.

IF97 artefacts are also available in the Maven Central Repository and can be added to your Maven project dependencies section:


This library has no dependencies on other software libraries, except for the test classes which require JUnit.

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See IF97 in action on our engineering portal:

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Available Properties

Below table shows which properties are available as a function of the two arguments shown in brackets above the columns. Refractive index requires the wavelength of light as an additional third argument. Some properties only require one argument and are denoted as ✓sat., e.g. saturated pressure as a function of temperature only.

(p, T)(p, h)(p, s)(h, s)(T, s)(ρ, T)(p, x?)(T, x?)
absolute pressurep✓sat.
dielectric constantε
dynamic viscosityη
isobaric cubic expansion coefficientαv
isothermal compressibilityκT
kinematic viscosityν
Prandtl numberPr
refractive indexn
specific enthalpyh
specific entropys
specific Gibbs free energyg
specific internal energyu
specific isobaric heat capacitycp
specific isochoric heat capacitycv
specific volumev
speed of soundw
surface tensionσ
thermal conductivityλ
thermal diffusivityκ
vapour fractionx
partial derivative(z/x)y

Partial derivatives can be specified using the com.hummeling.if97.IF97.Quantity enumeration. For example, the partial derivative of pressure with respect to enthalpy for constant temperature is retrieved as follows:

double dp_dh = if97.partialDerivativePT(3, 300, IF97.Quantity.h, IF97.Quantity.T, IF97.Quantity.p);

Note that partial derivatives are returned in the DEFAULT unit system, so (p/h)T would be in MPa·kg/kJ.

Using IF97 in Java

I Code Java
  1. Add IF97 to the imports: import com.hummeling.if97.IF97;
  2. Create an IF97 object: IF97 if97 = new IF97(IF97.UnitSystem.ENGINEERING);
  3. Retrieve a property: double v = if97.specificVolumePT(3, 300);

When arguments are out-of-range, an com.hummeling.if97.OutOfRangeException is thrown, which states the exceeded limit. This class contains methods that return the limit, double getLimit(), the quantity, String getQuantity(), and the exceeding value, double getValue().

Unit systems

Use IF97.UnitSystem enumeration to select a unit system:

absolute pressurepMPabarPapsi
dielectric constantε----
dynamic viscosityηPa·sPa·sPa·scP
isobaric cubic expansion coefficientαv1/K1/K1/K1/R
isothermal compressibilityκT1/MPa1/MPa1/Pain²/lb
kinematic viscosityνm²/sm²/sm²/scSt
Prandtl numberPr----
refractive indexn----
specific enthalpyhkJ/kgkJ/kgJ/kgBTU/lb
specific entropyskJ/(kg·K)kJ/(kg·K)J/(kg·K)BTU/(lb·R)
specific Gibbs free energygkJ/kgkJ/kgJ/kgBTU/lb
specific internal energyukJ/kgkJ/kgJ/kgBTU/lb
specific isobaric heat capacitycpkJ/(kg·K)kJ/(kg·K)J/(kg·K)BTU/(lb·R)
specific isochoric heat capacitycvkJ/(kg·K)kJ/(kg·K)J/(kg·K)BTU/(lb·R)
specific volumevm³/kgm³/kgm³/kgft³/lb
speed of soundwm/sm/sm/sft/s
surface tensionσN/mN/mN/mlbf/ft
thermal conductivityλW/(m·K)kW/(m·K)W/(m·K)BTU/(hr·ft·R)
thermal diffusivityκm²/sm²/sm²/scSt
vapour fractionx----
wavelength of lightλLμmμmmin

Note that partial derivatives are returned in the DEFAULT unit system, so (p/h)T would be in MPa·kg/kJ.

MATLAB is a registered trademark of The MathWorks, inc.

Accessing IF97 from MATLAB

Our IF97 library can be accessed easily from within MATLAB since Java is standard shipped with MATLAB. First add IF97.jar to MATLAB's dynamic class path
>> javaaddpath path_to_IF97.jar

Select your preferred unit system
>> unitSystem = javaMethod('valueOf', 'com.hummeling.if97.IF97$UnitSystem', 'ENGINEERING');

Create an instance of the IF97 class
>> if97 = com.hummeling.if97.IF97(unitSystem);

Retrieve a property, e.g., specific volume as a function of pressure and temperature as follows
>> if97.specificVolumePT(3, 300)

Alternatively, the Java archive can be added to MATLAB's static class path by editing your classpath.txt file, see your documentation for more details. Or you could add the javaaddpath statement to your MATLAB startup file, startup.m.

For a list of available methods issue the following command
>> methodsview(if97)

Contact Us

Hummeling Engineering BV

For more information, contact us: .

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We've also implemented the more accurate (but slower) formulation for scientific and general use, IAPWS-95. Contact us for more information.