6. Thin-film boil-over

6.1 Description of the phenomenon

Thin film boil-over is similar to conventional boil-over in that it leads to the sudden evaporation of a layer of water at the bottom of the tank. In thin-film boil-over, on the other hand, the product is consumed during the tank fire, without any distillation taking place; there is therefore no heat wave formation. The cause of vaporization of the water layer is then the flame front itself, when the liquid height is low enough for the heat flux transmitted by the flame to impact the water layer. In this case, the eruptive phenomenon characteristic of classic boil-over is restored, but the quantities involved are much smaller.

The "known" products likely to generate thin-film boil-over are FOD, diesel and kerosene. Thin film...