Experiments showing burn behavior of aluminum and plastic composite panels subjected to EXTERNAL heat source which produces similar burn effects but when removed, the panel self-extinguishes quickly. Note the drips of liquid plastic falling from the vertical panel, as well as some that ignite into mini rockets while the heat source is applied. Urethane foam looks easily extinguishable. Note that he could not get the test foam in the steel cup to ignite on its own and it was apparently edited out of the experiment. The piece he is holding was more irregular shaped with more surface area exposed. The intense flames on the Grenfell tower that could not be extinguished with water must have been sourcing its own oxidizer. (my theory) also, normal flames cannot spread down a chimney, and this seems to be the observed case.