Functional Safety Suite

Functional Safety Suite is a tool for calculations in the field of functional safety. It is free of charge.

Main characteristics and abilities

Model types:

  • Event trees.
  • Architecture block diagrams, that can be converted to fault trees.
  • Fault trees.
  • Reliability block diagrams.
  • Markov models.
  • Complex component models (components with several time variant failure modes).


  • A graphical user interface to create and edit models.
  • Event Trees
  • Architectures: Automatic creation of fault trees based on block diagrams.
  • Extended Fault Trees: also repairable systems can be modelled and evaluated correctly.
  • Extended Reliability Block Diagrams: different parallel structures available
  • Extended Markov models: not only transition rates but also transition probabilities.
  • Conversion of Fault Trees to Reliability Block Diagrams and vice verse.
  • Conversion of Fault Trees to Markov models, including common causes and condition events.
  • Steady state quantitative evaluation of all models.
  • Transient (time-variant) evaluation of Fault Trees and Markov models.
  • Supports modularization of Fault Trees.
  • Supports linking between models.
  • Many occurance/failure models for basic events.
  • Easy handling of common cause failures, even through transfer-gates and combination gates.
  • Graphical output of unavailability, unreliability and occurance rate (failure frequency) as function of time.
  • Extended Markov models: events (e.g. restoration) at discrete times.
  • Modeling, simulation and graphical analysis of complex components with different failure modes (safe and unsafe) with time variant rates, incl. detailed calculus of the characteristic values (e.g. b10, b10_d, MTBF, MTBF_d etc.).
  • Export of all graphical representations in bitmap (PNG) or vector graphics format (SVG, DrawingML).
  • Export of the prime implicants (minimal cut-sets) in HTML or CSV format.
  • Export of transient data in CSV format.
  • Analysis of the importance of basic events or generic basic events to the top event of a Fault Tree or Markov model.
  • No proprietary or binary file formats: all data is stored in XML text files.

Version 6.0.2

New in version 6.0.2

  • Conversion of 3-input Inhibit Gates (If-Then-Else-Gates) to Markov models

New in version 6.0

  • Architectures: Automatic creation of fault trees based on block diagrams.
  • Floating window: Show two models on your monitor(s).
  • Interationalization: Descriptions can be entered and saved in multiple languages, the selected one will be shown.
  • Copy chart axes configuration from one chart to another chart.
  • The User Interface Look & Feel can be selected.

Bugfixes in version 6.0.2

  • Text size in DrawingML exports corrected

Bugfixes in version 6.0.1

  • remove unnecessary warnings in fault tree evaluation
  • correct position of vertical text in DrawingML
  • adjust width of text fields in properties panel

Bugfixes in version 6.0

  • Scaling for high resolution displays corrected.
  • Export to docx updated due to new XML schemes of MS Word.

Upgrade from version 6.0 or 6.0.1 to version 6.0.2

If you’ve already installed version 6.0 or 6.0.1, it is sufficient to replace the core file FunctionalSafetySuite_6.0.jar by FunctionalSafetySuite_6.0.2.jar. Download FunctionalSafetySuite_6.0.2.jar only (1.566.375 Bytes), without templates, examples and documentation. After you’ve replaced the file, you’ll either have to adjust your link or rename it to FunctionalSafetySuite_6.0.jar.

Upgrade from version 5.x to version 6.0.x

All projects created with version 5.x or older can be opened in version 6.x and vice versa. If you save a project, that has been created or modified with version 6.0, with an older version, any architectures and additional languages will be removed.


The file fusasu_6.0.2_installer.jar includes the program, the documentation (pdf and html) and some examples.

Download Functional Safety Suite 6.0.2 Installer
fusasu_6.0.2_installer.jar (35.233.697 Bytes)

If the installer doesn’t work for your system, please use the .zip file instead:

Download Functional Safety Suite 6.0.2 Zip-File (33.521.860 Bytes)


Minimum System Requirements

  • 40 MB harddisk space (without JRE, this will need another 125 MB)
  • ~400 MB RAM (including JVM)
  • Java SE Runtime Environment Version 11.0 or higher
  • 1024x768 screen size (min. 1600x900 highly recommended)

In order to run Functional Safety Suite you’ll need a JAVA(TM) virtual machine (JVM, also called JAVA Runtime Environment, JRE) on your computer. You’ll find binaries for private and commercial use and for most operating systems on, e.g. for MS Windows x64 and Linux x64.

Note that it is not even necessary to have administrator rights: both the above mentioned Java Runtime Environment and Functional Safety Suite are shipped as .zip files as well, that only need to be extracted to some directory, e.g. the user directory. See Installing Functional Safety Suite with standard user rights below for details. In any case, no registry entries or similar will be set or modified, all preferences will be stored in a file in the user directory.

The installer will run on Microsoft Windows as well as on some Linux distributions. It will guide you through the installation, and will create short-cuts automatically. Download the .jar file to any directory and double-click on the .jar file. If the Java Runtime Environment (JRE) is installed correctly, the installation will start. If nothing happens, open a command line, go to the directory where you’ve downloaded the installation file and type java -jar fusasu_6.0.2_installer.jar. If this doesn’t work either, go to Installing Functional Safety Suite with standard user rights below.

If you’re running Linux, you might need to change the ‘executable’ flag on the file dist/FunctionalSafetySuite_6.0.2.jar. If short-cuts were added to the menu, remove them and make new ones to the file stated above. Installing from the archive might be slightly faster for linux users, anyhow.

If you cannot start the installer from the command line, your Java Runtime Environment (JRE) is not installed correctly. In that case, you can try to solve the issue be checking the JAVA_HOME and the PATH system variables, see or If you need the JRE only for Functional Safety Suite, or if you don’t have the necessary rights on your system, proceed as discribed in the next section.

Installing Functional Safety Suite with standard user rights

If for some other reason the installer doesn’t work, please download the .zip file instead and extract it to some folder. A directory FunctionalSafetySuite_6.0.2 will be created with some sub-directories. The only difference is, that no short-cut will be created automatically, i.e. you’ll have to create the short-cut as follows: Right-Click on the desktop, select New - Link. Select the file FunctionalSafetySuite_6.0.2.jar below the installation folder, e.g. D:\Programme\FunctionalSafetySuite_6.0.2\dist\FunctionalSafetySuite_6.0.2.jar. After giving it a name, a link will be produced. If the JRE is installed including its system variables, the link will already work. If the JRE is installed without system variables (e.g. by just extracting the .zip-file found on to some directory), edit the link (right-click on it and select Properties) by adding the path to javaw.exe, e.g. D:\Programs\AdoptOpenJDK\jdk-\bin\javaw.exe -jar D:\Programs\FuSaSu_6.0.2\dist\FunctionalSafetySuite_6.0.2.jar. Finally you can change the icon used by the short-cut, you’ll find an icon .ico and a .png image in the installation directory.

If you have problems installing Functional Safety Suite, please write an email to Please send the output of java -version as well. Please also try java -jar dist\FunctionalSafetySuite_6.0.2.jar (after changing to the installation directory of Functional Safety Suite).

The installer will not change any system parameters or libraries. Therefore, for de-installation you simply need to delete the directory that has been created during installation.

Functional Safety Suite will create a file fusasuV4.prop in the user’s default directory. If you change from Functional Safety Suite version 4.x or 5.x to 6.x, the old file will be reused. An already existing license file will be re-used as well.

Legal aspects

The complete license is part of the download (see file license.txt). The following is only a short excerpt.

Functional Safety Suite including the documentation is provided “as is” without any warranty to their performance, correctness or fitness for any particular purpose. The licensee assumes the entire risk as to the quality and performance of the software. In no event shall the author or anyone else who has been involved in the creation, development, production, or delivery of this Software be liable for any direct, incidental or consequential damages, such as, but not limited to, loss of anticipated profits, benefits, use, or data resulting from the use of this software, or arising out of any breach of warranty.

Functional Safety Suite Demo Edition

Differences between the Demo Edition and the full version:

  • Disclaimer shown at program start.
  • Export of graphics, reports and some data not enabled.
  • Some conversions not enabled.

To obtain a license for full functionality of Functional Safety Suite for free, please write to

Please state the name of your company or for which purpose you intend to use Functional Safety Suite. You’ll receive the license within three days typcially, except when I’m in holidays or on a business trip.


Event tree:


Fault tree:

Reliability block diagram:

Markov model:

Complex component:

Chart of complex component values:

Old versions

Functional Safety Suite 5.1.0

This version is replaced by 6.0.2, see above. It is recommended to upgrade to version 6.x since version 5.1 is no longer maintained. Version 5.1 should only be used if you want to exchange data with users still using version 5.1

The file fusasu_5.1.0_installer.jar includes the program, the documentation (pdf and html) and some examples.

Download Functional Safety Suite 5.1.0 Installer
fusasu_5.1.0_installer.jar (25695 kB)

If the installer doesn’t work for your system, please use the .zip file instead:

Download Functional Safety Suite 5.1.0 Zip-File (23827 kB)