Post-earthquake Fire Spread Research Articles

Possibility of Suppressing Fire Spread in the Event of a Large Earthquake by Greening and Demolishing Vacant Houses

In recent years, disaster mitigation measures by greening and demolition of vacant houses to prevent large post-earthquake fire spread have been promoted. However, few studies evaluate its effects on reducing property damage and human casualties, especially in vulnerable areas for earthquakes, such as densely built-up wooden residential areas. In this paper, we develop a model to describe the delay of post-earthquake fire spread between neighboring buildings, and incorporate it into the simulation model. Using the integrated model, we evaluate the reduction of the number of burnt-down buildings and human casualties in densely built-up wooden residential areas, and demonstrate the effectiveness of greening and demolition of vacant houses.

Multi-Objective Evcuation Planning Model Considering Post-Earthquake Fire Spread: A Tokyo Case Study

As an integral part of the 2030 Agenda for Sustainable Development, Disaster Risk Reduction (DRR) is essential for human safety and city sustainability. In recent years, natural disasters, which have had a tremendous negative impact on economic and social development, have frequently occurred in cities. As one of these devastating disasters, earthquakes can severely damage the achievements of urban development and impact the sustainable development of cities. To prepare for potential large earthquakes in the future, efficient evacuation plans need to be developed to enhance evacuation efficiency and minimize casualties. Most previous research focuses on minimization of distance or cost while ignoring risk factors. We propose a multi-objective optimization model with the goal of reducing the risk during the evacuation process, which is called the risk reduction model (RRM). Problem-specific indicators for screening optimal solutions are introduced. The research selects the Ogu area in Tokyo as a case study, where there is a relatively high density of wooden structures, increasing the risks of building collapse and fire spread after an earthquake, and is based on a two-phase evacuation flow that considers secondary evacuation for fire response. The results indicate that, in this case, RRM can, in most situations, reduce the risk level during the evacuation process and improve evacuation efficiency and success rate without significantly increasing the total evacuation distance. It proves to be superior to the traditional distance minimization model (DMM), which prioritizes minimizing the total distance as the objective function.

Post-Earthquake Traffic Simulation Considering Road Traversability

Post-earthquake road traversability is a critical factor that affects traffic conditions. Therefore, a post-earthquake traffic simulation method considering road traversability was proposed in this study. First, the impact ranges of the earthquake-induced building collapse and the post-earthquake fire spread of buildings were analyzed, and road traversability was determined accordingly. Subsequently, the post-earthquake traffic flow was predicted based on building characteristics, and micro-level vehicle behaviors were simulated considering post-earthquake road traversability to determine the traffic conditions. In addition, the simulation model was validated using actual data. Finally, a segment of the Tongzhou road network in Beijing was selected as a case study to analyze post-earthquake road traversability and simulate traffic conditions on critical road sections. The proposed method can provide post-earthquake traffic conditions, which benefits the decision-making of post-earthquake evacuation and rescue.

A suggested model for mass fire spread

ABSTRACT Fire following earthquake possesses significant risk of damages to life and property in urban areas. Mitigation and planning can reduce the level of risk associated with post-earthquake fire spread. This paper presents the details of a model that can be used to simulate mass urban fire spread based on the building material. The mechanisms of fire spread both within a building and building to building have been considered. For modelling building-to-building fire spread, the effects of direct flame impingement, heat transfer by convection and radiation, and flaming brands have been included in the model. A cellular automata scheme of modelling was employed for the construction of model. The model was implemented using a free-source computer programming framework which allows integration of building information data in geographic information system and mathematical formulation of fire spread mechanics. The results of the model have been compared with the existing data of mass urban conflagration. The employed algorithm was found to be stable which eliminates the need of large number of iterations to obtain reliable predictions. The results of the model correlated well with the existing data of fire-related damages and extent of fire spread available in the literature.

A Physics-Based Model for Post-Earthquake Fire Spread considering Damage to Building Components Caused by Seismic Motion and Heating by Fire

The prototype model previously developed by the authors was improved in order to simulate the behavior of fire spread in an earthquake-affected urban area. In the new model, seismic motion and heating by fire are both considered as the causes of damage to building components. The damage affects the burning behavior of a fire-involved building, as well as the behavior of building-to-building fire spread. For validation of the new model, a simulation of the fire spread that followed 1995 Kobe earthquake was conducted. The behavior of the fire spread obtained by the numerical simulation was compared with the observed data. Reasonable agreement was obtained with regard to the number of burned buildings.

Experimental study and modeling of radiation from compartment fires to adjacent buildings

This paper presents twelve full-scale experiments conducted on radiation from compartment fires to a target wall. The impact of different window sizes, separation distances between the fire building and a target wall, and different fuels on radiation heat fluxes on target wall is investigated. The contribution of external flame to radiation heat flux on target wall was studied. The emissivity of external flame is analyzed which shows that the experimental value is larger than that suggested by previous studies. The experimental data have been compared with theoretical results. The discrepancy between experimental and theoretical data has been explained. The limitations and recommendations of some equations have been discussed. Furthermore, a modeling of radiation heat flux on target wall from post-flashover compartment fire is proposed. This work is expected to be used as the basis to develop modeling of fire spread between buildings, modeling of post-earthquake fire spread and modeling of urban/wildland interface fire spread.

Modeling and Estimating Post-Earthquake Fire Spread

This paper describes the development of a GIS-based dynamic fire-spread model, with seven distinct modes of fire spread: direct contact, spontaneous ignition of claddings, piloted ignition of claddings, spontaneous ignition through windows, piloted ignition through broken windows, fire spread via non-fire-rated roofs and branding. All except the first two modes include in-built probabilities, but these can be selected individually and given user-defined values. Fire spread modes can be added to the model or altered to suit available building information. Critical details of buildings are obtained from an existing-buildings database, street surveys, or deduced using conditional probabilities from available data. Results show that comparison with actual fires is reasonable. The model could be extended with further development for use as a real time firefighting tool.

A Post-Earthquake Fire Spread Model considering Damage of Building Components due to Seismic Motion and Heating of Fire

A physics-based model for post-earthquake fire spread was developed by modifying the prototype model previously proposed by the authors. In the model, fire spread within urban area is simulated by predicting behavior of individual building fire under the thermal influence of other building fires. Target urban area consists of buildings with diverse level of damage due to seismic motion. The damage may even be progressed by heating of fire following earthquake. Damage of building members affects behavior of building fire as well as the criteria for building-to-building ignition. Indices representing the damage of building are as follow: bearing capacity of column; deficit ratio of walls and windows; and falling ratio of exterior material. Bearing capacity of a representative column is used as criteria for determining the collapse of entire building. Deficit on walls and windows may intensify combustion in fire involved room by letting fresh air supply from adjacent rooms. At the same time, this may cause room-to-room fire spread since it drastically augments the rate of heat transfer by radiation. Falling of exterior material let unprotected combustible exposed to external heating that increases probability of ignition. For the model validation, fire spread simulation in Kobe city at the time of 1995 Hyogo-ken Nanbu Earthquake was carried out. Reasonable agreement was obtained between observed and simulated behavior of fire spread.

BURN-DOWN RISK OF ARCHITECTURAL MONUMENTS SURROUNDED BY GROUP OF WOODEN HOUSES DUE TO POST-EARTHQUAKE FIRE SPREAD

Burn-down risk of seven architectural monuments in Kyoto-Higashiyama area due to post-earthquake fire spread was analyzed. The analysis was conducted by the Monte Carlo simulation using a physics-based urban fire spread model formerly developed by the authors. Factors of uncertainty considered in the present analysis were the conditions on: (1) outbreak of fire; (2) firefighting activity at initial stage of fire; (3) structural damage of individual buildings due to seismic motion; and (4) change of weather in time series. The result shows that burn-down risks of Rokuharamitsuji, Hokanji and Kenninji are rather close to the mean value of all the houses in the target urban area. The result indicates that no fire-stops are maintained between these architectural monuments and densely-built wooden houses in their surroundings. Thus, integrated approach involving entire urban area is required on implementing fire safety measure in order to effectively reduce the burn-down risk of the architectural monuments.

A Post-Earthquake Fire Spread Model considering Damage of Building Components due to Seismic Motion and Heating of Fire

A Post-Earthquake Fire Spread Model considering Damage of Building Components due to Seismic Motion and Heating of Fire

Application of a Physics-Based Simulation Model to Examine Post-Earthquake Fire Spread

For 50 years, post-earthquake fire spread models used the basic empirical, macro approach developed by Hamada in 1951. Recently, however, a few physics-based models have emerged in which different modes of fire spread (e.g., radiation, branding) are modeled separately, more realistically, and in more detail. Using a case study for Los Angeles, this article illustrates how a new physics-based model developed by the authors can be used to estimate how much, how fast, and where fires spread, and also to provide insight into how fires spread and factors that influence fire spread.

Physics-Based Simulation Model of Post-Earthquake Fire Spread

This article describes a new model that simulates the spread of post-earthquake urban fires. Adapting and integrating compartment fire models, this new model explicitly represents: (1) the evolution of fire within a room or roof; (2) room-to-room spread within a building through doorways, by burning through walls and ceilings, and by leapfrogging between windows; and (3) building-to-building spread by window flame impingement; radiation from window flames, room gas, and roof flames; and branding. The model can be used to explore how much, how fast, where, and by what modes fires will spread, and what factors influence fire spread.

DEVELOPMENT OF A SIMPLIFIED MODEL FOR URBAN FIRE SPREAD BY USING A QUASI-STEADY CALCULATION METHOD

Evacuation of a large number of residents is conceivable in case of urban fires following a large earthquake. It is essential to implement an effective evacuation plan for ensuring residents' safety. We have been developing a simulation model based on the potential theory for the evacuation behaviors of city residents, which has been validated by comparing the predicted and the recorded evacuation behaviors of residents in the Great Kanto Earthquake Fire. In this model, fire spread was estimated based on after event field survey of the fire. However, in case of an evacuation simulation in a post-earthquake fire which may take place in future, it is essential to predict the fire spread itself. In this study, a computationally efficient model for post-earthquake fire spread in a large-scale urban area was developed based on several findings established in the field of fire safety engineering. In the proposed model, fire behaviors inside a building were formulated into quasi-steady state equations in order to reduce computational load, and the data quantity in calculation was minimized for applying to fire spread in a large-scale urban area. In this paper, the fire spread in the Sakata City Fire in 1976 was simulated for the model validation and the results were discussed in terms of fire spread behavior, computational speed and data quantity in calculation. The obtained results showed that the proposed model could simulate the fire spread with reasonable accuracy and with much less computation time and data quantity.

A MODEL FOR POST-EARTHQUAKE FIRE SPREAD CONSIDERING STRUCTURAL DAMAGE OF BUILDINGS CAUSED BY SEISMIC MOTION AND ITS PROGRESSION DUE TO HEATING OF FIRE

A physics-based model for post-earthquake fire spread was developed by modifying the prototype model previously proposed by the authors. In the new model, seismic motion and heating of fire are both considered as the causes of damage upon building members. The damage results in the change of fire behavior for individual building and criteria for building-to-building ignition. Indices representing the structural damage of a building are as follow: inclination angle of columns; falling ratio of exterior claddings; and deficit ratio of partitioning walls. Charring of wooden column gradually reduces its bearing capacity along with the decrease in its area of cross section. This may yield buckling of the column as well as collapse of the entire building. As to the falling of exterior claddings and burn-through of partitioning walls, the rates of degradation are assumed to be proportional to the cumulative heat flux received by the building members. The falling of exterior claddings increases the probability of ignition due to external heating, and the burn-through of partitioning walls allows transfer of heat and mass between neighboring rooms. For the verification of the new model, simulation of fire spread which followed 1995 Kobe Earthquake was conducted. Behavior of fire spread obtained by the numerical simulation was compared with the survey data at which reasonable agreement was obtained.

Post-earthquake Fire Spread Between Buildings Estimating And Costing Extent In Wellington

Fires after earthquakes sometimes develop into conflagrations resulting in widespread losses of life and property. A geographic information system (GIS) model linked to property and valuation data is shown to be an appropriate tool for estimating urban fire losses. One approach uses a static buffering technique to define potential burnout zones that are sampled randomly to give estimates of losses. The other uses a dynamic cellular automaton technique for determining both the rate and extent of fire-spread in response to a wide range of factors including wind, radiation, sparking, branding, building separations and building claddings. The dynamic approach uses a set of ‘rules’ based on fire physics modified by historical data. The model runs in real time for single ignitions. The static method is used to estimate losses assuming a 12m separation will prevent fire spread All buildings are assumed combustible (upper bound case). The dynamic model assuming fire can not spread to buildings with non-combustible claddings and areas of vegetation are not flammable (lower bound case). The resulting losses are between NZ$50M and NZ$500M (excluding building contents), compared with NZ$5,000M for shaking losses for a magnitude 7.3 earthquake and a total building stock of NZ$19,000M.