Impacts of ceiling height on the combustion behaviors of pool fires beneath a ceiling

To examine the effect of varying ceiling height on the combustion behaviors of pool fires whose flame impinged the ceiling, a series of n-heptane pool fires was performed beneath a ceiling in the range of H_ef/DÂ =Â 0.43–2.5 using a scaled-down calorimeter. Typical parameters including the burning intensity, combustion yields and combustion efficiency were quantitatively analyzed. It was found that with the decreasing ceiling height, the burning intensity initially increased to a peak at H_ef/DÂ =Â 1.38 and then decreased, exhibiting a parabolic variation tendency. The maximum concentration increments of CO and CO₂ showed the parallel results to the burning intensity, while the total amount of CO yield monotonously increased with the declining ceiling height, implying increasing toxicity. Besides, the carbon conversion ratio produced the similar result as the combustion efficiency, and both of them showed the parabolic variation law.