Page 22 - A Burning Question Fire Debris
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Lab
Procedure
LAB 1
ANALYSIS OF IGNITABLE LIQUIDS PRESENT IN KNOWN
FIRE DEBRIS SAMPLES
1. Prior to analyzing evidence collected from the 4. Puncture the label on the lid of the container
crime scene, you will practice the techniques with the end of the colorimetric tube.
required to identify the presence of ignitable
liquids in non-evidentiary known samples 5. Carefully break both ends off of the tube
of fire debris. When breaking the ends off of being used by inserting the tube end
colorimetric tubes, glass edges may be sharp through the colorimetric tube opener to just
so great care must be taken when handling past the ball. With the tube pointed away
fragments. Do not handle glass fragments from your body, grasp the side of the tube
without wearing proper personal protective opener and twist downward to break the end
equipment, including gloves and goggles. off of the tube.
2. Determine which groups will perform which 6. Carefully insert the colorimetric tube
analysis - three groups will analyze the samples through the lid. Ensure that the arrow on
for the presence of gasoline and three groups the tube (indicating direction of airflow)
will analyze the samples for the presence of is pointed toward the outside of
diesel fuel. the container.
3. Select the sample container and colorimetric 7. Roll a small piece of colorimetric tube sealant
tube appropriate for analysis (Ex. gasoline into a rope and use this to seal the opening
spiked sample and gasoline colorimetric tube) between the tube and the lid. Ensure no
and ensure the lid is securely tightened onto openings remain that would allow vapors to
the container. escape.
22 THE MYSTERY OF LYLE AND LOUISE
