Fire Safety Science Digital Archive

Oil storage tanks which are subjected to intense heat radiation from a nearby fire will absorb heat which will raise the temperature of the layers of flammable liquid adjacent to the side of the tank. This liquid will tend to rise to the surface by convection and the temperature and pressure in the vapour space above the liquid surface will rise accordingly. There will be an increase of vapour loss from the vent, and in an extreme case where the vent area is restrictive the pressure within the tank may rise to dangerous limits. In such cases a rupture of the tank may occur with catastrophic results; even if this stage is not reached, there is the danger that the vapour plume from the vent may "flash" from the adjacent fire, or from some other source of ignition. To prevent this sequence of events occurring, it is necessary to cool the exposed surface of the tank by a water film. In the following experiments, one method of providing this film was tested for its efficiency of coverage of the roof and sides of the tank. The note does not discuss whether the total quantity of water supplied was adequate to keep the tank cool under specified intensities of incident heat radiation this aspect will be discussed in a later note.