Fire Scene Evidence Collection Guide
Ignitable Liquid Residue & Fire Debris
Wood Floor
Detailed Procedure:
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Select a productive sampling area. Productive sampling areas include:
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Within an area of ignitable liquid indicators, such as a suspected pour pattern
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In an area where ignitable liquid may collect, such as the lowest point on the grade
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Edge of a burn pattern or suspected pour pattern
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At junctures with furniture and walls
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Joints
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Vertical grain
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On stair treads at the joint between riser and tread
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Select appropriate new or properly cleaned tools, such as a chisel and mallet, to cut out the sample.
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Select a new, metal paint can container.
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Photograph the sampling area.
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Wear new, unused, clean latex or nitrile gloves.
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Use the chisel and mallet to break into the wood, preferably ½ inch on either side of a seam or next to the baseboard, as liquids tend to collect in seams, and up to the joint. Break out a wood sample that includes the material in the seam and directly underneath the seam (include subfloor if possible).
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Place the wood sample in the paint can. If the sample is large, break it into smaller pieces to fit into the container. Make sure to leave 1/3 headspace in the can.
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Clean the lip of the can using a clean screwdriver or other suitable tool.
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Gently tap the top of the lid with a clean rubber mallet to seal it. Do not dent the can because it may compromise the seal. Seal the container(s) with evidence tape, and initial and date the tape.
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If possible, collect a comparison sample from a location not within the ignitable liquid pattern and not in the room of origin. Place the comparison sample in a separate container using new gloves and a new or properly cleaned tool. A comparison sample for ignitable liquids testing will help the laboratory exclude compounds occurring naturally in the wood floor.
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Label each container with identifying information, including case number, date, exhibit number, a brief description including recovery location, and your name.
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Store the item(s) in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.
Laboratory examination of wood floor for ignitable liquids:
Wood floors can be tested for ignitable liquids using gas chromatography mass spectrometry. This test can determine the classification of the ignitable liquid.
Source:
interFIRE. "Evidence Sampling for Ignitable Liquids Testing." Online Training Module, 2013: