The Limitations and Advantages of Ultraviolet Light Sources in the Detection of Ignitable Liquids at

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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

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UV in Arson Investigation

• Ultra violet lights marketed to arson
  investigators for decades
• Very few reliable studies to support their claims

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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

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Ultraviolet Light Source

• Model UVSL-26P by UVP in California
• Rechargeable
• Three modes of operation
• Short wave (254nm)
• Long Wave (365nm)
• Dual

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Testing Performed

• Amount of Ignitable Liquid
• Time Exposure
• Visualization of Various Ignitable Liquids
• Visualization on Various Materials
• Visualization on Various Burnt Materials

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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

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I. Amount of Ignitable Liquid

• All amounts detectable on carpet and asphalt tile

50 µL gasoline on asphalt tile
50 µL gasoline on carpet
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I. Amount of Ignitable Liquid
10 µL gasoline on carpet
10 µL gasoline on asphalt tile
300 µL gasoline on asphalt tile
300 µL gasoline on carpet
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I. Amount of Ignitable Liquid
Close-up 10 µL gasoline on carpet
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II. Time Exposure

• All tested on carpet and asphalt tile
• 30 minutes
• 60 minutes
• 120 minutes
• 180 minutes
• 240 minutes
• 300 minutes

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II. Time Exposure

• All amounts detectable on the tile and carpet at
  10 months

10 months later
1st Day
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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

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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
• 90gt75gt50gtnon-weathered
• Base gasoline not detectable
• Gasoline from various companies indistinguishable

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III. Ignitable Liquids Tested
Weathered Gasoline
50
90
75
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IV. Flooring Materials Tested

• Carpet
• Linoleum
• Foam Carpet Padding
• Fiber Filled Carpet Padding
• Asphalt Tile
• Wood Flooring

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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

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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

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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

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V. Burnt Materials Tested

• Carpet
• Linoleum
• Foam Carpet Padding
• Fiber Filled Carpet Padding
• Asphalt Tile
• Wood Flooring

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V. Burned Materials Tested
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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

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Additional Results

• Dawn detergent masks ignitable liquids from the
  canine teams but no affect on fluorescence
• Exposure to water does not affect fluorescence

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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

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Acknowledgements

• Don Brucker, Allegheny County Fire Marshals
  Office
• Bob Huston, Allegheny County Crime Laboratory
• Dr. Graham Rankin, Marshall University

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References

• DeHaan, J. D. Kirks 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.

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Questions???