The inclination effect on CO generation and smoke movement in an inclined tunnel fire

The study of the tunnel’s inclination effect on the fire in an inclined tunnel is of vital importance to the evacuation of people during a conflagration in a tunnel. When a fire emergency happens in an inclined tunnel, the inclination affects, the temperature, the visibility, the thickness of carbon monoxide (CO), and the movement of the smoke. In this paper, the inclination effect is studied in terms of the CO concentration and the smoke movement pattern in an inclined tunnel fire. A series of experiments are conducted with the inclination angles varying from −10° to 10° to the horizontal and with n-Heptanes pool fires in three pans of various sizes. It is found that the CO concentration is negatively correlated with the inclination angle and the thickness of smoke layer and the smoke outflow rate are both positively correlated with the inclination angle. Those negative and positive correlations also suggest a negative correlation between the CO concentration and the smoke layer thickness or smoke outflow rate.

► We conduct fire and smoke experiments in a reduced-scale tunnel with inclined angles.
► The CO concentration is negatively correlated with the inclination angles.
► The thickness of smoke layer and the smoke outflow rate are positively correlated.