# Assessing Crisis Management Tools for Sustainability of Industrial Safety
## 4 Model Situation
### Results of Evacuation Models for Each Scenario  
The ALOHA software simulations provided a comprehensive analysis of ammonia leak scenarios, producing color-coded risk zones that showed varying levels of ammonia concentration in the air. These simulations are vital tools in the field of crisis management, enabling planners to develop effective evacuation strategies based on real-time data and predicted hazard distributions. These simulations are critical for determining evacuation zones and planning optimal evacuation routes based on the predicted spread of the hazardous substance. Furthermore, the software offers time-based data, predicting how ammonia concentrations evolve over time, aiding emergency services in effectively planning their responses to critical exposure levels. In Scenario 1, the simulation revealed key danger zones based on the concentration of ammonia in different areas. The evacuation models were tailored according to these concentrations, with rapid evacuations necessary in ERPG-3 zones, where ammonia concentrations reached 1500 ppm. Within these zones, the population needed to evacuate within 10 min to avoid severe health impacts. In ERPG-2 zones, where concentrations reached 150 ppm, evacuation could be delayed by up to 30 min without risking serious long-term health effects. Such detailed hazard assessment is crucial for informing decision-makers and enhancing community preparedness for potential ammonia leak incidents. These insights emphasise the value of early warnings and accurate modelling in optimising evacuation routes and timing, ensuring minimal exposure to harmful concentrations. In Figure 5, the evacuation simulation for Scenario 1 is displayed. This figure outlines the primary evacuation directions (represented by red arrows), and the critical buildings marked for evacuation (indicated by yellow pins). The simulation assists emergency planners in identifying areas that must be evacuated to minimise the risk of exposure to hazardous ammonia concentrations. Figure 5: Model showing an evacuation simulation for Scenario 1. The data in Table 7 provide specific details about the danger zones for Scenario 1. In ERPG-3, where ammonia concentrations reached 1500 ppm, the zone extended 110 m from the source. This zone represents the most dangerous area where exposure can cause serious health effects. The ERPG-2 zone extended to 362 m with concentrations of 150 ppm, presenting a serious health risk. Finally, ERPG-1, the least severe zone, spanned 895 m with concentrations of 25 ppm, where health risks are lower but still present. Figure 6 presents the driving route for rescue services in Scenario 1, as modelled in ALOHA. This figure is crucial for planning the approach of rescue teams, optimising their routes to avoid exposure to hazardous substances. The red triangle marks the location of the fire and rescue units, with blue arrows indicating their route to the scene. Yellow pins mark important structures, including schools and medical centres, requiring immediate evacuation. Under Scenario 2, the rescue route was designed to minimise exposure to thermal radiation from a pool fire of a hazardous substance. Figure 7 illustrates this rescue route, which takes into account the need to avoid the most dangerous zones while allowing rapid \begin{table}
\begin{tabular}{l l l l} \hline \hline \multirow{2}{*}{**Danger Zone**} & \multirow{2}{*}{**Concentration (ppm)**} & **Equivalent** & \multirow{2}{*}{**Range (m)**} \\  & & **Concentration** & **(mg.m\({}^{-3}\))** & \\ \hline ERPG-2 & 150 & 104.479 & 362 \\ ERPG-1 & 25 & 17.413 & 895 \\ IDLH & 300 & 208.958 & 254 \\ \hline \hline \end{tabular} Note: The colour coding used for hazard zones, with yellow for ERPG-1 (low risk), orange for ERPG-2 (moderate risk), red for ERPG-3 (high risk), and purple for IDLH (immediately dangerous to life and health), reflects increasing levels of risk due to ammonia concentration.  
\end{table} 
Table 7: Danger zones for Scenario 1.