Fire Safety Science Digital Archive

A series of tests have been carried out on the extinction of transformer oil fires 3 and 4 ft diameter with water sprays from a range of single nozzles. The tests were carried out in a roofless structure in the open air. Within the range of rates of fIow to the fire and drop sizes tested (0.45 - 7.0 g cm^-2 min^-1 and 0.4 - 3.0 mm respectively) the extinction time was approximately inversely proportional to the rate of flow and directly proportional to the drop size. No significant effect of the entrained air velocity of the spray was detected; this may have been due to the scatter of the results which was much wider than with small-scale tests carried out in the laboratory. In all tests but one, the liquid was cooled to below the fire point prior to extinction. In some tests however the liquid was cooled to wall below the fire point without extinction; the maintenance of fire in these cases was due to the burning of oil drops splashes upwards into the flame.