EXPERIMENTAL MEASUREMENTS OF UPWARD FLAME SPREAD ON A VERTICAL WALL WITH EXTERNAL RADIATION

The overall objective of the project is to gain an understanding of th e flame spread phenomenon under simulated surrounding fire conditions. In this phase of the project, emphasis is placed on obtaining experim ental data for upward flame spread with applied external radiation on practical wall materials. A second phase (not yet reported) is the dev elopment of a numerical flame spread model and the experimental result s presented here will be used for comparison with model predictions. F lame height, and in some cases pyrolysis height, were recorded as func tions of time for 120 cm x 30 cm samples; and these data were used to quantitatively investigate the effect of external radiation on several materials. Infrared heating panels were used to supply radiant fluxes of up to 15 kW/m(2) to the sample. Many wood-based materials do not e xhibit flame spread to the top of the sample when ignited without appl ied external flux. With moderate levels of external radiation (5-10 kW /m(2)), many of these materials sustained flame spread to the top of t he sample. With increasing external radiation levels, flame spread was also more rapid. A comprehensive series of tests was run on particle board to investigate the effect of igniter strength, preheat of the sa mple, and sample thickness. Igniter strength was not a significant fac tor and did not cause the flame spread to be sustained; the effect of preheat, even at moderate levels of radiant flux, was important; and s ample thickness had a slight effect, with thicker samples burning slow er. Total heat feedback to the sample was measured and the maximum val ues for various samples are reported. Experimental data obtained in th is project will be used to aid in the development and validation of a numerical flame spread model. (C) 1998 Elsevier Science Ltd. All right s reserved.