Fire Spread Risk Analysis of Outdoor Sidewalk by Directed Graph Model Based on Network Topology

There is a fire risk on the modern city sidewalk. Changing the design and layout of shops on the sidewalk leads to changes in the risk of fire on the sidewalk. Thus, a directed graph model based on the network topology structure is proposed to analyze the risk of fire spread on the sidewalk in this study. The proposed method determines the expected fire spread loss (risk) on the sidewalk in multiple scenarios. The influence of adding or deleting nodes and edges on the fire spread of the sidewalk is analyzed with the method. By retrofitting the fire protection facilities of the four shops numbered on the sidewalk and strengthening fire management, the maximum loss on the sidewalk reduces by 40.2%, and the expected loss reduces by 55.8%. By adding new nodes, the planning and layout management of sidewalk shops can be guided. It is avoided to add dangerous things in the concentrated area of shops or at the "bridge nodes" of connected subgraphs.