NCFS Support of SWGDE and T/SWGFEX Projects/Activities - T/SWGFEX Portion

• NCJ Number: 240689
• Author(s): Michael Sigman, Ph.D.; Mary Williams, M.S.; Carrie Whitcomb
• Date Published: June 2012
• Length: 91 pages
• Grant Number(s): 2008-IJ-CX-K401
• Agencies: NIJ-Sponsored
• Publication Type: Program/Project Description
• Award: NIJ Support of TWGFEX/SWGDE Projects & Activities (2007-2008)

Annotation

This report addresses the National Center for Forensic Science's (NCFS) funding for specified projects/activities of the Technical/Scientific Working Group for Fire and Explosion (T/SWGFEX).

Abstract

Three major tasks of the T/SWGFEX were funded by the NCFS: Maintenance and expansion of the Ignitable Liquids Reference Collection and Database (ILRC); Smokeless Powders Database development; and implementation of a Searchable Ignitable Liquid Database. An additional 120 reference ignitable liquids were added to the ILRC, bringing its database entries to 614, making it the largest collection of reference ignitable liquids with an associated database of analytical data. The collection contains reference ignitable liquids that span all ASTM E1618 classes and carbon ranges from various U.S. geographical areas and time frames. Part of this project involved the development of a new database that contains data from the burning of common substrates (building materials). The Smokeless Powder Database is a regularly updated reference collection of powders obtained from various sources, including vendors and manufacturers. It is designed to assist forensic explosives analysts in characterizing, classifying, and comparing smokeless powder samples based on their physical and chemical properties. It opened with 100 records, and approximately 800 total records are being processed for release. A searchable ignitable liquids database tool has also been developed by the T/SWGFEX. It is based on the use of the total ion spectrum (TIS) for finding the best match between a fire debris sample and ignitable liquids in the ILRC. The Match criterion is based on the use of several distance and similarity metrics. A search of the entire ILRC can be completed in a fraction of a second. Similarly, a sample can be searched against the Substrates Library. 22 figures, 13 tables, and appended supplementary data