Testing the wildland urban interface fire evacuation tool WUI-NITY: A case study of a rural community

Abstract

This thesis makes use of a freely available platform based on multi-physics simulations, named WUI-NITY, to model WUI fire evacuation. This simulation platform includes three sub-models addressing fire spread, pedestrian movement and traffic movement allowing the representation of their interaction to produce outputs useful for dynamic vulnerability assessment. The goal of the thesis is to test the WUI-NITY platform for a set of WUI fire evacuation scenarios in a rural community by taking into consideration the evacuation component of the model. In addition, the sensitivity of the model results to the input values assigned are investigated. A default scenario is first constructed based on an evacuation drill conducted by the Roxborough Park (Colorado, USA) WUI community. Five variables were selected to test the sensitivity of the platform to model inputs. The values were changed from the default scenario to generate 15 different scenarios adopting the one at a time (OAT) sensitivity analysis approach. The variables considered are total population, response time of the agents, number of available goals as exits, shelter capacity and the activation of a lane reversal order. The simulations run in WUI-NITY were able to capture the expected impact of each variable. For most of the scenarios, the total evacuation time differs by a maximum of 5 minutes. However, for the scenarios with longer response time and the unavailability of Goal F as an exit, the total evacuation time differs by 11 to 40 minutes. The scenarios under consideration included limited congestion on the road. Results from the scenarios considering as variable the available goals and shelter capacity were highly influenced by the road network data. As the evacuation time does not differ much, the evolving condition during the evacuation is of more interest to illustrate how many people are left in vulnerable condition. This is possible to derive from the simulations run in WUI-NITY.

Popular Abstract

The world has seen many intense wildfires in recent years than ever before. When these wildfires extend to a populated wildland-urban interface (WUI) area, lives and properties of the residents are in danger. Thus, to protect the WUI communities from such deadly hazards, it is important to issue a timely evacuation order. Moreover, the way a WUI community responds to an evacuation order can significantly affect the outcome of a WUI fire. With these in mind, the study attempts to test the modelling capability of the WUI fire evacuation tool WUI-NITY.
The WUI-NITY platform is capable of simulating the dynamic conditions during an evacuation by coupling wildfire spread, pedestrian movement and traffic movement layers. The platform is a recently introduced and freely available tool to model WUI fire evacuation. In order to test WUI-NITY, the study made use of the data collected from an evacuation drill conducted in Roxborough Park community (Colorado, US). Considering the conditions in the drill as the base, a default scenario was constructed. This scenario then served as a benchmark to construct another 15 scenarios. The scenarios differ from each other depending on the values assigned to five selected variables. The variables are – total population, response time of people, availability of different goals as a safe area, limiting the capacity of this safe area, and the activation of a lane reversal order. The scenarios are then simulated in the WUI-NITY platform to produce quantitative results for a vulnerability assessment.
One of the interesting findings of this study is the influence of response time. The resulting total evacuation time and the evolving conditions during the evacuation are largely influenced by the response time of the evacuees. When people responded within a short period, it took them less time to evacuate to safety, enabling them to leave the threatened area swiftly. Moreover, despite the large inflow of vehicles due to quick response, the roads were not congested. This implies that the road network of the community has enough capacity. On the contrary, when people responded late to the order, the total evacuation time increased significantly. In this case, there is a little chance of congestion in the roads, as the vehicles enter the road network over a longer period. Furthermore, results from the scenarios present evidence that the dynamic condition during the evacuation is of more interest than just reporting the total evacuation time.
The platform is still on its development stage. A proper validation is required for the better use of this tool to simulate WUI fire evacuation. This study can be considered an initial step towards this task. WUI-NITY can be useful to educate the WUI community residents about their responsibilities during such incidents. Additionally, incident managers and emergency responders can also benefit from using the tool, by planning a safe and timely evacuation before and during an incident.

• author: Mallick, Afroza
• supervisor: Enrico Ronchi
• organization: Division of Fire Safety Engineering
• course: VBRM05 20211
• year: 2021
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: WUI-NITY, fire evacuation tool, evacuation, wildland-urban interface.
• publication/series: LUTVDG/TVBB
• report number: 5640
• other publication id: LUTVDG/TVBB—5640--SE
• language: English
• id: 9049019
• date added to LUP: 2021-06-07 11:00:07
• date last changed: 2021-06-07 11:00:07