In the United States, approximately 85% of all fire deaths are attributed to residential fires. In 2007, residential fires caused almost 2,900 civilian fire deaths, 14,000 civilian fire injuries, and more than $7.5 billion in property damage. Often of interest in residential fires, particularly those involving loss of life or serious injury, is reconstruction the fire development timeline: first item ignited, resultant fire spread rates, time to smoke alarm activation (if present), effect of sprinkler or other fire suppression (if present), time to flashover, and time to incapacitation due to heat or carbon monoxide uptake. Putting together all of these puzzle pieces, and trying to figure out what happened, is the process of forensic fire reconstruction. Reax Engineering fire experts conduct forensic fire reconstructions and analysis of residential fires using science and engineering, including fire dynamics and fire modeling tools. Some aspects of a residential fire that can be analyzed with computer fire models or other engineering tools include fire growth rates; time to activation of smoke detectors, heat detectors, and sprinklers; window breakage; onset of flashover; and loss of tenability along the means of egress pathway.