John A. Kennedy & Associates

Fire and Explosion Investigation Experts

USFA Burn Pattern Tests

W. Alletto, R. Corry, J. Herndon, P. Kennedy, J. Ward, J. Shanley, 1997

Fire Patterns, Fire Behavior, Full Scale Burns, Fire Origin, Flashover, Accelerant.

The first Scientific study into the formation, growth, nature and investigative analysis of post-fire patterns.

Abstract

Fire patterns are the visible or measurable physical effects that remain after a fire. These include thermal effects on materials, such as charring, oxidation, consumption of combustibles, smoke and soot deposits, distortion, melting, color changes, changes in character of materials, structural collapse, and other effects.

The first scientifically controlled and recorded research into the formation, growth, nature, and investigative analysis of post-fire patterns was conducted in 1994-1995, by the United States Fire Administration under the direction of a specially appointed research committee of fire investigation experts. To provide data for the research, the United States National Institute of Science and Technology, Building and Fire Research Laboratory (NIST- BFRL) facilitated ten full-scale room fire tests. The purpose of the testing was to provide basic research into the true nature of fire patterns used by fire investigators to make determinations of fire origins and fuels.

The results indicated that general fire patterns provide definitive data useful for the determination of the origin of fires. It was found that fire patterns are influenced by a number of variables. The most notable of these from this research, was ventilation and flashover. In some particular cases ventilation was shown to be able to change or move patterns to such an extent that the correct interpretation of the pattern was made more difficult. The room fire phenomena of flashover was observed in a majority of the test fires. It was found that flashover was able to obscure some patterns present on room surfaces prior to flashover, including patterns from ignitable liquids used as an accelerant.

Results and conclusions were also reached in the areas of: floor patterns, truncated cone patterns, floor jets, trailers, burning under furniture items, low level burning, depth of gypsum wallboard dehydration, water spray patterns, color of smoke, and the detection of ignitable liquids.

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