I am involved in a fire investigation. It concerns a fire occurred in private home, in particular the fire was started in a cavity where there are a chimney and other plants.
I have already isolated the cause of the fire and I have studied the fire patterns, in particular I have attached a photo that shows the classic V pattern and that highlights the ignition point in an elbow of the chimney.
Furthermore I have to point out that the chimney was really bad insulated, bad supported and there were too much 45° elbow in the path(six elbow). The chimney go through the roof, and wood fiber insulation is in front of the chimney (separated by 3 cm gap of air)
The chimney was connected to a pellet stove. The pellet stove had a nominal heat output of 17 kW and the IMQ test made on the stove shows a mean flue gas temperature of 167°C.
The fire has occured the 28 december, and the chimney was installed just 2 month before this date. In my opinion a soot fire has occured, in fact the stratification of soot could be reinforced by the loss of pressure due to the elbows and to the heat loss (bad insulation).
Talking with the firefighting departments, they told me that just the smoke spills can cause the fire. I have tried to demonstrate if the radiant heat emitted by stratification of the hot smoke (using the temperature of a mean flue gas temperature of 167°C with Boltzmann formula) was enough to ignite the wood fiber insulation, but I cannot demonstrate it.
Can you help me to analytically demonstrate the possibility of the ignition due to the hot smoke stratification? I accept every advice thanks.