Why are cooktop fires so hazardous

Abstract A series of experiments was conducted characterizing the flammability properties of small-scale corn oil fires. The oil was placed in a pan located on the center of an electric coil heating element associated with an electric cooktop. Ignition was accomplished with a torch with the heating element off or by auto-ignition when the heating element was on. The mass loss, heat release rate, pan bottom temperature, heat flux to the surroundings, and flame height were measured. The radiative fraction and combustion efficiency were estimated from the measurements. Heating the oil on a typical electric cooktop leads to auto-ignition of the oil. Continued heating of the oil on the cooktop enhances the vaporization of the oil and leads to rapidly growing fires with relatively large peak heat release rates. Under some conditions, heated corn oil can boil-over, a phenomenon in which the oil bulk density decreases until it flows over the pan sides. For a given pan volume, the occurrence of boil-over depends on the initial fuel volume. Compared to traditional gasoline pool fires, the corn oil undergoing auto-ignition and continued heating had larger peak values of heat release rate and peak flame height by factors of 3.1 and 1.6, respectively.