FRSC 1011H Lecture Notes - Lecture 14: Gas Chromatography, Smokeless Powder, Deflagration
Fire Investigation and Explosives
Physical State of the Fuel
● A fuel achieves a reaction rate with oxygen sufficient to produce a flame only
when it is in the gaseous state. Thus, rusting will not be accompanied by a flame
Combustion Triangle
● Oxygen
● Fuel
● Heat
Fire Tetrahedron
● Heat
● Fuel
● Oxygen
● Chain reaction
Indicators of Arson
● The use of “streamers” to spread the fire from one area to another
● An irregularly shaped pattern on the floor resulting from the pouring of accelerant
into the surface
● Normally, a fire has a tendency to move in an upward direction and this the
probable origin will most likely be the lowest point showing the most intense
characteristics of burning
Gas Chromatography
● By comparing select gas chromatographic peaks recovered from fire-scene
debris to known flammable liquids, a forensic analyst may be able to identify the
accelerant used to initiate the fire. The gas chromatographic pattern of the
unknown is compared to patterns produced by known petroleum products
Low Explosives
● The most widely used explosives in the low explosive group are back powder
and smokeless powder
● Low explosives can be confined to a container like a pipe, The speed of
decomposition is called deflagration causing the walls of the container to
fragment and fly outward in all direction
Document Summary
A fuel achieves a reaction rate with oxygen sufficient to produce a flame only when it is in the gaseous state. Thus, rusting will not be accompanied by a flame. The use of streamers to spread the fire from one area to another. An irregularly shaped pattern on the floor resulting from the pouring of accelerant into the surface. Normally, a fire has a tendency to move in an upward direction and this the probable origin will most likely be the lowest point showing the most intense characteristics of burning. By comparing select gas chromatographic peaks recovered from fire-scene debris to known flammable liquids, a forensic analyst may be able to identify the accelerant used to initiate the fire. The gas chromatographic pattern of the unknown is compared to patterns produced by known petroleum products. The most widely used explosives in the low explosive group are back powder and smokeless powder.