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Re: Definition of "Weathered" Ignitable Liquid Residue (ILR)
Posted by: PMK140 (IP Logged)
Date: July 13, 2007 07:35AM
The ISFI 2006 International Symposium on Fire Investigation Science and Technology
paper: Comparison of Gasoline Weathering on Carpet Samples Exposed to Various Thermal Environments, by Jamie L. Ferrino-McAllister, MScFPE, P.E., C.F.E.I., Douglas J. Carpenter, MScFPE, C.F.E.I., P.E., and Richard J. Roby, P.E., Ph.D., all of Combustion Science & Engineering, Inc., USA. does not seem to agree with this assessment.
In its introductory section the research paper states:
“Previously performed work concerning scene contamination supports the hypothesis that such contamination does occur under certain conditions. The contamination of a fire scene can be detrimental to the accurate analysis of physical evidence and can reduce its evidentiary value. While gas chromatography and mass spectrometry (GC/MS) techniques can identify the presence, quantity, and extent of “weathering” (i.e. evaporation) of ignitable liquids found in fire debris, these techniques cannot be used to determine if the flammable or combustible liquids were used to initiate the fire or were present due to fire scene contamination. Currently, there is no data or methodology in the available scientific literature that would support such a determination.
The conclusions sections states:
“The gasoline samples exposed to the fire were 75% to 90% weathered, while those exposed to nominal room temperatures were 25% to 50% weathered. Based on these results and the weathering of the samples recovered from the fire scene, it is clear that the gasoline found on the evidence was weathered at near room temperatures and, thus, had to be introduced after the fire was suppressed. This research suggests a clear delineation between samples exposed to fire conditions and those exposed to ambient conditions; however, the determination of the percentage of gasoline weathering is subject to the interpretation of the chemist performing the GC/MS analysis; therefore, continued work is needed to further refine the use of such data.”
Pat Kennedy, CFEI, CFPS, MIFireE
Fire and Explosion Analyst
Sarasota, Florida
[www.kennedy-fire.com]
paper: Comparison of Gasoline Weathering on Carpet Samples Exposed to Various Thermal Environments, by Jamie L. Ferrino-McAllister, MScFPE, P.E., C.F.E.I., Douglas J. Carpenter, MScFPE, C.F.E.I., P.E., and Richard J. Roby, P.E., Ph.D., all of Combustion Science & Engineering, Inc., USA. does not seem to agree with this assessment.
In its introductory section the research paper states:
“Previously performed work concerning scene contamination supports the hypothesis that such contamination does occur under certain conditions. The contamination of a fire scene can be detrimental to the accurate analysis of physical evidence and can reduce its evidentiary value. While gas chromatography and mass spectrometry (GC/MS) techniques can identify the presence, quantity, and extent of “weathering” (i.e. evaporation) of ignitable liquids found in fire debris, these techniques cannot be used to determine if the flammable or combustible liquids were used to initiate the fire or were present due to fire scene contamination. Currently, there is no data or methodology in the available scientific literature that would support such a determination.
The conclusions sections states:
“The gasoline samples exposed to the fire were 75% to 90% weathered, while those exposed to nominal room temperatures were 25% to 50% weathered. Based on these results and the weathering of the samples recovered from the fire scene, it is clear that the gasoline found on the evidence was weathered at near room temperatures and, thus, had to be introduced after the fire was suppressed. This research suggests a clear delineation between samples exposed to fire conditions and those exposed to ambient conditions; however, the determination of the percentage of gasoline weathering is subject to the interpretation of the chemist performing the GC/MS analysis; therefore, continued work is needed to further refine the use of such data.”
Pat Kennedy, CFEI, CFPS, MIFireE
Fire and Explosion Analyst
Sarasota, Florida
[www.kennedy-fire.com]
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