One‐ and two‐sided burning of thermally thin materials

The rate of heat release from a thermally thin material burning on both sides will be more than twice the value seen when only one side is burning. Two simplified models demonstrate that this is a consequence of the Arrhenius temperature dependence of the gasification rate of the solid. Experiments carried out on three composite materials over a range of incident heat fluxes confirm this effect. It is inferred that a further consequence of this heat release enhancement is an increased tendency for concurrent flame spread in the two‐sided burning case. Materials whose application could lead to two‐sided burning should thus be assessed in this mode to obtain a true picture of their flammability potential.