Citation

Heskestad G, Dobson PH. Fire Safety J. 1997; 28(1): 33-46.

Copyright

(Copyright © 1997, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Experiments are reported on pool fires of transformer oil (flash point 157[deg]C) burning over a rock bed in a 1.2 m diameter pan, with and without drainage from the bottom of the pan. Levels in the pool are referenced to the mean rock surface level (MRSL), defined as the horizontal plane (level of oil) where 50% of the area of the plane is broken by the surface rocks of the rock bed. Without drainage, using a rock type having a mass median diameter of 23 mm and with an initial oil level 51 mm above the MRSL, there was little change in heat release rate until the oil level regressed 25 mm below the MRSL; subsequently, the heat release rate fell sharply and continued at a low rate for greater than 3 h, when the flames were extinguished manually. With drainage at regression rates of 16-26 mm/min, used in most of the experiments, there was no appreciable decrease in heat release rate until the oil regressed below the MRSL in this case, and the fires self-extinguished when the oil level dropped 23-29 mm below the MRSL, depending on rock type (two types investigated). Heat release rates during active combustion (~ 570 kW/m2 convective) were little affected by oil drainage, the initial oil level, the preburn interval or the rock type in the ranges investigated.