Training Backdraft

A small quantity of pine is placed in a modified shipping container and the fuel is ignited. When fully developed, the doors are closed until the flaming combustion ceases. The compartment is then opened and the result is a backdraft. Note the colour of the smoke. It is almost white. The fuel in the container is pyrolysing due to the residual heat. This is the production of fuel vapour and passive agents. The white smoke is fuel rich and hot enough to auto-ignite. When it dilutes down to the flammable range