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The Limitations and Advantages of Ultraviolet Light Sources in the Detection of Ignitable Liquids at Fire Scenes. Sarah Kunkel 2006 MAAFS Annual Meeting May 5, 2006. UV in Arson Investigation. Ultra violet lights marketed to arson investigators for decades - PowerPoint PPT Presentation
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The Limitations and Advantages of Ultraviolet Light Sources in the Detection of Ignitable Liquids at
Fire Scenes
Sarah Kunkel
2006 MAAFS Annual Meeting
May 5, 2006
UV in Arson Investigation
• Ultra violet lights marketed to arson investigators for decades
• Very few reliable studies to support their claims
Ultraviolet Light Test Objectives
• Determine capabilities of UV light source
• Determine limitations of UV light source
• Determine whether UV light source is a practical approach to ignitable liquids detection at fire scenes
Ultraviolet Light Source
• Model UVSL-26P by UVP in California
• Rechargeable• Three modes of
operation– Short wave (254nm)
– Long Wave (365nm)
– Dual
Testing Performed
I. Amount of Ignitable Liquid
II. Time Exposure
III. Visualization of Various Ignitable Liquids
IV. Visualization on Various Materials
V. Visualization on Various Burnt Materials
I. Amount of Ignitable Liquid
• All amounts of gasoline tested on carpet and asphalt tile– 10 μL– 25 μL– 50 μL– 100 μL– 150 μL– 300 μL
I. Amount of Ignitable Liquid• All amounts detectable on carpet and
asphalt tile
50 μL gasoline on asphalt tile
50 μL gasoline on carpet
I. Amount of Ignitable Liquid
10 μL gasoline on asphalt tile
300 μL gasoline on asphalt tile
10 μL gasoline on
carpet
300 μL gasoline on
carpet
I. Amount of Ignitable Liquid
Close-up:
10 μL gasoline
on carpet
II. Time Exposure
• All tested on carpet and asphalt tile
– 30 minutes
– 60 minutes
– 120 minutes
– 180 minutes
– 240 minutes
– 300 minutes
II. Time Exposure• All amounts detectable on the tile and
carpet at 10 months
1st Day
10 months
later
III. Ignitable Liquids Tested• All liquids tested at 10 μL and 50 μL on
asphalt tile• Ignitable liquids tested:
– Gasoline (Unevaporated, 50%, 75%, and 90% evaporated, and Base)
– Diesel fuel– Lighter fluid– Linseed oil– Various ignitable liquids used to calibrate the
canine detection team
III. Ignitable Liquids Tested
• Only gasoline, diesel fuel, and linseed oil detectable on all material at all amounts
• Weathered gasoline fluoresces brighter than non-weathered
– 90%>75%>50%>non-weathered
• Base gasoline not detectable
• Gasoline from various companies indistinguishable
III. Ignitable Liquids Tested
90% 75% 50%
Weathered Gasoline
IV. Flooring Materials Tested
• Carpet
• Linoleum
• Foam Carpet Padding
• Fiber Filled Carpet Padding
• Asphalt Tile
• Wood Flooring
IV. Other Materials Tested
• 100% White Cotton T-shirt• Jeans• Human Skin• Manila Folder• White Printer Paper• White Notebook Paper• Yellow Notebook Paper• Paper Towel
IV. Flooring Materials Tested• Must use only short wavelength on
linoleum
• Carpet and asphalt tile worked under long, short, and dual wavelength
• Mostly questionable positives for fiber filled carpet padding and wood flooring
IV. Other Materials Tested
• Negative results on jeans and cotton t-shirt
• Skin– Remain detectable on skin between 8-9 hours– Canine team did not detect after 3 hours – Fluoresced after 5 hand washings
• Paper products– Both liquids fluoresced on all paper products– Light absorbed when liquid was still wet
V. Burnt Materials Tested
• Carpet
• Linoleum
• Foam Carpet Padding
• Fiber Filled Carpet Padding
• Asphalt Tile
• Wood Flooring
V. Burned Materials Tested
V. Burnt Materials Tested
• Only short and dual wavelengths visualized the ignitable liquids
• Gasoline less visible than diesel fuel on all materials
• Results varied from unburned materials– Less positive results – Carpet absorbed light
Additional Results
• Dawn detergent masks ignitable liquids from the canine teams but no affect on fluorescence
• Exposure to water does not affect fluorescence
Conclusions
• UV light only useful in detection of gasoline and diesel fuel
• Not affected by water, but burning of material does affect visibility
• Useful with small volumes and at long exposure times
• Fluorescence caused by dyes in ignitable liquids
Acknowledgements
• Don Brucker, Allegheny County Fire Marshal’s Office
• Bob Huston, Allegheny County Crime Laboratory
• Dr. Graham Rankin, Marshall University
References• DeHaan, J. D. Kirk’s Fire Investigation 4th edition. Prentice Hall,
1997. 405-11.• Forestal, R. Use of Ultraviolet Light in Fire/Arson, Bomb, and
Environmental Investigation. Firehouse Magazine September 1994: 48-50
• Brucker, D. Chief Deputy Fire Marshal, Allegheny County Emergency Services. July 18-27, 2005. Pittsburgh, Pennsylvania.
• U.S. Fire Administration. Arson in the United States (Topical Fire Research Series). The Administration. January 2001. 1(8): 1-3
• Ultra-Violet Products. Use of Ultraviolet Light in Arson Detection [Application Bulletin-UVP-AB-107]. 1997
• Stauffer, Eric. Technical Working Group for Fire and Explosives Discussion. March 21, 2006.
Questions???