I'm struggling to interpret 921's graphs FIGURE 5.6.3.2.1(a) & -(b), which look contradictory to me.

(I'll attach 5.6.3.2.1(a), & -(b) in the next post )


As per 921's description :

5.6.3.2.1 In addition to these factors, experimental data show that while the incipient stages
of fires can vary dramatically, the growth rates leading up to flashover are generally similar
for a given fuel regardless of the presence of an accelerant. HRR curves for upholstered sofa fires are shown in Figure 5.6.3.2.1(a) and Figure 5.6.3.2.1(b) for a sofa burning;
in the open, within an unventilated apartment structure, and within a ventilated apartment
using two different ignition scenarios (small 10 kW fire and gasoline poured on the sofa).
These figures illustrate the time differences associated with the incipient stages of fire development in various scenarios [Figure 5.6.3.2.1(a)] and also show the similarity in the fire growth stage for all four scenarios when compared on a common timeframe [Figure 5.6.3.2.1(b)].