iSiGG | ein dynamisches, interaktives Simulationssystem für Feuer-, Rauch- und Schadstoffausbreitung in Gebäudenben bei Interaktion mit Personen

Fire and Hazardous Gas Dispersion simulation

model based on CFD techniques

The software developed during iSiGG simulates in a realistic way the conditions that occur during a fire incident. It can be applied to fire propagation, fire suppression and smoke management in any type of buildings as well as for general thermal modeling. It can be used to calculate safety and comfort

Indices for the design and construction of buildings. To this end, the software takes into account environmental conditions : HVAC systems, air flow velocity, temperature, relative humidity, thermal radiation and contaminants. All buildings objects like walls, floors etc. can be modelled with their thermal characteristics. The same applies to doors, windows and furniture. HVAC devices can transport contaminants and heat through the building and are modelled as specialized boundary conditions.

Two main Versions are available

FlogoCFD: parallel solver for unsteady, turbulent incompressible flows enhanced with heat and mass transfer/buoyancy effects.

Numerical method characteristics:

  • Flow and heat transfer equations are solved strongly coupled.

  • It is based on the pseudocompressibility concept for the solution of steady/unsteady, 2D/3D, turbulent flows and it uses hybrid unstructured meshes.

  • Dual time stepping: Second order  three point backward scheme in physical time, first order backward Euler implicit scheme in pseudotime. Local time stepping in pseudotime for convergence acceleration.

  • Upwind scheme for inviscid fluxes (second or third order accurate for mean flow and first order accurate for turbulence model)

  • Central scheme for viscous fluxes (second order accurate)

Turbulence Models

  • Standard k-ε turbulence model

  • k-ω SST

  • k-ω ΤΝΤ

  • k-ε MMK

  • Large Eddy Simulation (LES)


  • Parallel CFD code based on the MPI protocol (MPICH2 and OpenMPI 64 bit implementations). The Single Program Multiple Data (SPMD) approach has been adopted. Mesh partitioning in subdomains is required to assign each processor/node a subdomain.

  • Applied on hybrid unstructured meshes.

  • Radiation model based on Finite Volume Method.

  • Contaminant concentration field (soot, combustion products)

  • Fire suppression by sprinklers (Lagrangian treatment and droplets’ tracing).

  • Simulation of HVAC systems.

  • 1D simplified heat conduction through walls coupled with the CFD simulation.

New Capabilities (iSiGG)

  • Automatic model generation from IFC (IFC4) files. Recognition of spaces, simplification of geometry and imposition of boundary conditions.

  • Advanced models for heat radiation

  • Heat Release Rate Properties of different materials

  • Implemetation of dynamic geometrical elements

  • Incorporation of HVAC and BACS

  • Modelling of active and passive fire protection systems

  • Modeling of toxic gas dispersion considering additional buoyancy effects

  • Coupling with crowd simulation application for evaluating evacuation strategies via a TCP/IP communication model

  • Participation of smoke in the modeling of thermal radiation

  • Material library with suitable properties

  • Fire spread on the lining and the furniture. More precise models for combustion modeling.

  • Evaluation of the results according to human safety criteria. Definition of suitable metrics/KPIs

Areas of Application:

  • Home Land Security Sector for the simulation of fire and toxic gas dispersion events

  • indoor climate prediction with emphasis to thermal comfort

  • FlogoFFD: Fast parallel solver for unsteady, turbulent incompressible flows enhanced with heat and mass transfer/buoyancy effects running on GPUs and multiple GPUs. FFD code on GPUs renders real-time simulations feasible. FlogoFFD has significant novelties:It is the only code in literature that uses unstructured mesh. The other codes exploit the data structure of Cartesian orthogonal meshes to save computing time.

  • FlogoCFD and FlogoFFD code share the same mesh/boundary conditions/post processing saving a lot of procedural work for the end user.

  • All data structure calculation and space derivative are common for the CFD-FFD codes.

  • CFD and FFD can be used as supplementary tools for:

  • Remarkable increase of the accuracy of the FFD code through a calibration process

  • Offering a great initial field for the CFD simulations

FFD new capabilities in the context of iSiGG:

  • Fire suppression systems by using mixed Eulerian and Lagrangian approach (to save memory and computing time and to tackle GPUs’ memory limits).

  • Insertion of pollutants’ dispersion model. Investigation of various CBRNs.

  • Interaction of pollutants’ dispersion models with HVAC systems. Active control.

  • Interaction with outdoor conditions (climate conditions).

  • Modeling of the crowd, bidirectional communication between the two systems.

  • Dynamic geometrical elements (active or passive regarding fire protection).

  • Sprinklers

  • Complementary use of CFD and FFD applications for system integration needs.