Fire dynamics in simulation based training

This article covers the possible usecases realistic fire dynamics into virtual firefighter training.
Those simulations can provide additional realism and new training possibilities, but are not needed for every constantly. Hence, its not a common feature in most software, but rather an ongoing topic for various academic projects, some of it even dating back to 1997 [Firewalk].

The following article only considers computational fluid dynamics (CFD), that produces more accurate results than zone models. The accuracy happens at the expense of calculation time, so all datasets has to be precomputed.

The integration of external fire dynamics data is a considered feature for FireSim, but not implemented yet.

Usage

As a result of an CDF-Simulation, the following data are available for each coordinate at any given time:

  • Heat Release Rate of a fire
  • Temperature
  • Gas components such as oxygen, CO and CO2 and other toxic combustion compounds.
  • Location and density of smoke
  • Velocity of smoke and gas components

These data can be used for better rendering of fire and smoke, since the render-engine has additional information.

The behavior of non-player-characters can be affected by all those datasets.
The optical density of smoke can affect their path-finding, which is driven by the incentive to run away from fires. These behavior can be observed in the Auggmed project.
The metrics of temperature, O2, CO and CO2 can be used to determine injuries of non-player-characters and a ‘safety level’ for trainees.
This safety level is a measure to imply the consequences of fire and smoke. So when ignored, they lead to a fail state. For a safety level assessment, the trainees need additional visual or audible cues. See [Cha_2012] for an in-depth exploration of this topic.

With multiple runs of simulations calculated, it is possible to visualize ventilation and the effect that open or closed doors provide. Even the effect extinguishment can be taken into consideration.

A look into the future

Arguably, not every scenario needs fire dynamics data. At the moment its reserved for special use cases, with a lot of preparation needed. Basically its a resource heavy and scientific approach.
But algorithms get better and computers become more powerful, so calculation becomes faster.

The hardest part is the required knowledge for performing the simulation. Input values and material properties has to chosen according to the scenario and the inner workings of the CFD codes.

Literature and further reading

Key Title DOI / Link
Cha_2012 A virtual reality based fire training simulator integrated with fire dynamics data 10.1016/j.firesaf.2012.01.004
Firewalk The FireWalk System: Fire Modeling in Interactive Virtual Environments Download
Xu2014 A virtual reality based fire training simulator with smoke hazard assessment capacity 10.1016/j.advengsoft.2013.10.004
Moreno_2014 Interactive fire spread simulations with extinguishment support for Virtual Reality training tools 10.1016/j.firesaf.2014.01.005
Maschek2010 Real Time Simulation of Fire Extinguishing Scenarios Download