921: Changes In The Science Of Fire Investigations

I. Changes in the Science of Fire Investigations

The creation of the NFPA 921 Guide for Fire and Explosion Investigations (“921”) in 1992 by the National Fire Protection Association is arguably the most significant guide created for fire investigations. The 921 was designed by the Technical Committee on Fire Investigations to improve the fire investigation process by emphasizing the use of scientific method and inform those in both the private and public sectors about changes in scientific research regarding arson science. The Technical Committee on Fire Investigations currently has over 30 experts from a wide variety of backgrounds both within and outside the United States. In the years immediately following its creation, the document remained

Particularly, that more research is needed on “natural variability of burn patterns and damage characteristics and how they are affected by the presence of various accelerants.” The Report also recommends that new experiments should be designed to “put arson investigations on a more scientific footing.” The NAS Report noted the problematic start of all forensic science – in crime laboratories, instead of more academic arena, which caused a distinct lack of a “culture of science” among forensic scientists. Despite the creation with the 921 and developments in forensic science, many myths still permeate the fire investigations community, and some of these myths have certainly caused wrongful

There are two parts to fire investigations: the fire scene investigation, followed by the fire debris analysis. In the fire investigation phase, the primary focus must be to determine the origin(s) and cause(s) of the fire. The origin and cause are irrevocably connected: if the origin cannot be determined, then the cause cannot be determined, and further, if the origin determination is incorrect, the cause determination will also be incorrect. The fire debris analysis, more so like other forensic sciences, takes place in a lab where analysts attempt to determine whether ignitable liquid residues (“ILR”) are present, and if so, what the chemical nature of these ILRs are, and whether potential accelerants are found on the samples.

Upon arriving at the scene, investigators will often use a combination of the following sources to determine the origin of a fire: witness information and/or electronic data, fire patterns, arc mapper, and fire dynamics. The most commonly used method to determine the origin is fire pattern analysis. Unlike DNA analysis, which has been described as the gold standard for forensic science, fire-pattern analysis is deeply