“…, CO lower (al) 0 0 Figure 7 : Vertical temperature evolution at the room center During the second step ranging from t = 300 s to 600 s (noted step b in Figure 9), the temperatures measured in the fire compartment and at the opening do not evolve much ( Figures 4 , 7 and 8) ; on the other hand, in the center of the room, the 0, concentration in the lower zone keeps decreasing to reach about 2% at t = 600 s and the CO, concentration increases to reach nearly the same volume fraction than the upper zone. Considering the very low 0, concentration in the room, one can assume that the flame is below its extinction limit, usually assessed between 10% and 15% for most hydrocarbons [3,6,7,111. However, the temperature curves close to the pool fire ( Figure 8) indicate that the flame is probably not extinguished.…”