shortest evacuation process for three $\mu$ values.[]{data-label="plot_6"}](\DIR/fig12.eps){width="0.9\columnwidth"}

For $\mu=0$ the evacuation process is nearly deterministic in the ordered regime and the fluctuations (due to the random initial conditions and the dynamics) are very small. With increasing $\mu$ values the internal pressure is increased and the envelloping curves differ clearly from the averaged curves.

In figs. \[plot\_7\] and \[plot\_7b\] again the averaged curves together with the extremals are shown for the two densities $\rho=0.03$ (fig. \[plot\_7\]) and $\rho=0.003$ (fig. \[plot\_7b\]) and the two friction parameters $\mu=0$ and $\mu=0.9$. Here the same effects as for $\rho=0.3$ can be seen, but much clearer.

![Evacuated persons in dependence of time for the ordered regime; averaged, longest and shortest evacuation process for two $\mu$ values ($\mu=0$ and $\mu=0.9$) and density $\rho=0.03$.[]{data-label="plot_7"}](\DIR/fig13.eps){width="0.9\columnwidth"}

![Evacuated persons in dependence of time for the ordered regime; averaged, longest and shortest evacuation process for two $\mu$ values ($\mu=0$, $\mu=0.9$) and density $\rho=0.003$.[]{data-label="plot_7b"}](\DIR/fig14.eps){width="0.9\columnwidth"}

The time evolution of one single sample exhibits an interesting dynamics. In figs. \[plot\_6\]–\[plot\_7b\] small plateaus can be observed where over short time periods no persons leave the room. This irregular behaviour is well-known from granular flow and is typical for clogging situations [@granul0; @gran_1; @gran_2; @gran_3; @granul1; @granul2; 