# A Method for Evaluating the Spatial Layout of Fire Stations in Chemical Industrial Parks
## 2 Methods
### Estimated Fire Rescue Time  
To estimate the fire rescue time, it is necessary to establish a rescue road network for the chemical industrial park and estimate the running speed of the fire engines within the  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Fire Risk Score** & **Fire Risk Level** \\ \hline \(\text{R}\ \geq\ \overline{X}+\sigma\) & High \\ \(\overline{X}+\sigma\ >\ \text{R}\ \geq\ \overline{X}\) & Medium \\ \(\text{R}\ <\ \overline{X}\) & Low \\ \hline \hline \end{tabular}
\end{table}
Table 4: Classification of fire risk levels.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Criteria** & \multicolumn{5}{c}{**Scoring**} & \multirow{2}{*}{**Weight**} \\ \cline{2-2} \cline{4-6}  & **0** & **50** & **75** & **100** & \\ \hline Number of key supervised & & & & & \\ hazardous chemical processes & & & & & \\ Number of key supervised & & & & & \\ hazardous chemicals & & & & & \\ Level of major hazard installations & & & & & \\ of hazardous chemicals & None & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Scoring and weights for fire risk assessment indicators.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Fire Risk Level** & **Required Fire Rescue Time** \\ \hline High & 3 min \\ Medium & 5 min \\ Low & 8 min \\ \hline \hline \end{tabular}
\end{table}
Table 5: Required fire rescue time for corresponding fire risk level.  
park. The rescue road network mainly includes fire roads, fire stations, and PTBRs. An accurate PTBR in a chemical industrial park should be based on a specific object, such as a production facility, storage tank, or factory building. Relevant object information, such as contour lines and fire risk assessment results, should be obtained. The object should be transformed into a centroid point, and the relevant information should be provided as the attributes of this point. Obtaining the aforementioned data, however, involves significant difficulty and workload. Furthermore, the variety of these data sources may lead to significant differences in accuracy, which then hinders error control. In order to solve this problem, we adopt the concept of \"clustering\". In this article, the chemical industrial park is divided into several areas based on the enterprise's wall area or the public land parcels. The centroid of each area represents the total fire demand in that area, serving as a PTBR, and all the attributes of this area, such as the fire risk level, are assigned to this PTBR.  
The speed at which fire engines travel directly affects the fire rescue time, which is closely related to the quality of local road construction and traffic conditions. The chemical industrial park is relatively isolated, with fewer unrelated vehicles passing through its interior. The roads and traffic conditions in the chemical industrial park are similar to those in the suburban areas of the city. According to the current national standard in China [46], the designated driving speed for expressways in suburban areas is generally no less than 60 km/h. A statistical analysis was conducted regarding the average driving speed of the highway network in Shanghai from August to October in recent years. Taking into account the traffic conditions, the average driving speed of fire engines in suburban areas was determined to be 55 km/h [6]. Park X is located in the suburban area of a small city in Southwest China that is not as developed as Shanghai. Based on an analysis of the current road construction situation and the daily traffic conditions in Park X, it is estimated that the driving speed of fire engines is 50 km/h.