
From NIST study on candle flames. [Link to Paper]
Fire Dynamics Simulator (FDS) is a computational fluid dynamics (CFD) model of fire-driven fluid flow.
The software solves numerically a form of the Navier-Stokes equations appropriate for low-speed, thermally-driven flow, with an emphasis on smoke and heat transport from fires.
Smokeview (SMV) is a visualization program that is used to display the output of FDS and CFAST simulations.
Please read the manuals for each program and be aware that FDS is not a typical "point and click" computer program. Rather, FDS is run from the command line, and it requires that input parameters be written into a text file. Third party software is available to assist in the preparation of the input files and execution of the program, but this software is not necessarily free. See the 3rd Party Tools page for more information.
The Fire Dynamics Simulator and Smokeview applications are developed by the National Institute of Standards and Technology (NIST) of the United States Department of Commerce, in cooperation with VTT Technical Research Centre of Finland.

From NIST study on Oil Storage Tank Fires,
Prior to release of FDS [Link to Paper]
FDS and Smokeview is free software developed through the National Institute of Standards and Technology (NIST) by employees of the Federal Government in the course of their official duties. Pursuant to Title 17, Section 105 of the United States Code
. This work is not subject to copyright protection and is in the Public Domain
.
NIST assumes no responsibility whatsoever for use by other parties of its source code, documentation or compiled executables, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic. See the Disclaimer page for additional information.
Report to the Support Issue Tracker specific bugs or problems that you encounter with either Fire Dynamics Simulator (FDS), FDS+EVAC or Smokeview.
Please go to the Discussion Group, for general questions and/or to provide feedback related to your experience using FDS, Smokeview, the documentation, the web sites, etc.