Simulation of Fire Spread in Cable Tunnel with Different Fire Barriers

With the rapid growth of urban power transmission cable scale, the harmonic pollution in the high-voltage power grid is more transmitted to other power grids of different voltage levels, which makes the harmonic transmission more complicated, increases the harmonic emission level, and makes it difficult to quantitatively analyze and study the allowable value of users’ electrical pollution emission. Therefore, in this paper, by establishing the harmonic conduction model of the urban high-voltage power grid and considering the equivalent circuit of transformer and transmission cable in the urban power grid, the parameters of transmission cable harmonic transfer coefficient and the allowable emission value of power quality pollution of the urban power grid are deduced and quantitatively analyzed. Then the harmonic transmission and mutual influence of urban power network harmonics in power transmission cable are analyzed through examples, which is helpful to determine the allowable value of harmonic pollution emission scientifically and reasonably.

In recent years, the external thermal insulation composite system (ETICS) has been applied increasingly in a lot of buildings for energy conservation purposes. However, the increased use of different combustible insulation materials in the ETICS has raised serious fire safety problems. Fires involving this type of ETICS have caused severe damage and loss. Often, the fire spread depends on the thermal material of ETICS. Products of polymeric foams or inorganic fibrous material are commonly used. Practice and case studies of researchers show that involved expanded polystyrene is the most dangerous case of the fire spread. Therefore, it is important to choose the right material. In order to limit fire spread and improve fire safety, fire barriers from were suggested being installed. These measures may include the installation of a non-combustible lintel above each opening in the facade (windows, doors) to prevent flames penetrating the insulating material. Additionally, firestop barriers can be installed horizontally over the entire facade. The fire barriers have to be made of non-combustible materials, such as mineral wool, and are required on every alternate floor in buildings. Energy renovation is a great chance to increase fire safety in buildings. Therefore, the requirements of additional fire safety and prevention are different in Europe. Currently, there are not much data available on the behaviour of different insulation materials (expanded polystyrene and mineral wool) in ETICS and their relevant characteristics during operating life and ETICS durability time. This paper cites the requirements of additional fire prevention in different European countries. Analysis of the physical properties (vapour resistance, thermal transmittance, water absorption and etc.) of the expanded polystyrene and mineral wool products of is presented. This article presents an investigation of Thermo vision of building, which was renovated three years ago and has implemented fire barriers.DOI: http://dx.doi.org/10.5755/j01.sace.17.4.16140

Fire spreading is one of the visualization techniques used for re-enacting or envisions the fire incidents for conducting the post-incidents’ responses and analysing the incidents for post-mortem purposes. There are several current researches on the fire spreading incidents that involve the construction of fire spreading simulation which has focusing on the fire development, smoke control, the prediction of temperature distribution during the fire spreading, emergency response’s plans and post-fire damage assessment. However, there are more features need to be explored in the fire spreading simulation and also the pedestrians movement of the affected incident’s area for the future space design development, arrangement and structural improvement that are impactful towards human safety and also useful for the justification and prediction on the pedestrian survival rate during any panic situations. Hence, this research has focusing on the features of realistic scaling of the spatial layout and implementing the Cellular Automata (CA) approach for imitating the near-realistic pedestrian self-organizing movement and fire spreading characteristics at the microstructure level for designing the heat map of the affected area to show the clogging region in the spatial layout while constructing a reliable prediction on the pedestrian survival rate. This clogging region mapping will be useful for finding the existing issues that lead towards high casualties. Based on the experiments and observations, the heat map of the affected area showed the heavy congestions happened specifically near to the ingress/ egress points and narrow pathways that had affected the pedestrian flow rate and caused the 75% of the 352 pedestrians in the spatial layout to burn and die during the fire simulation by unintentionally taking an extra of 43.85 seconds more than the total fire spreading time (13.42 seconds) to evacuate from the closed area building.

Shanghai is one of China's highest levels of industrialization and most economically developed regions. In the backdrop of the development of smart grid, smart electric power industry will be to play a very important position in the Shanghai urban area's electric power industry. This paper will focus on the analysis of the present situation of Shanghai urban area's power grid, especially the basic skills and business models of the power demand side. It is researched that the blueprint of the Shanghai urban area's future power grid and achieving methods based on the related smart electricity work carried on in the current Shanghai urban area and its effectiveness, especially, the pilot project. The main work is as follows: the description of the current Shanghai urban area power grid, including the history, development and evolution, load characteristics level, reliability, power distribution automation level and so on. The presented situation of smart power, which mainly includes the information collection system pilot project, electric vehicle charging facilities pilot project, intelligent building pilot project, flexible DC power transmission pilot project, the power FTTH (Fiber to The Home) to households pilot project, especially combine with the smart grid key pilot projects, such as the smart power design and practice of Shanghai World Expo smart grid pilot projects, and point out the current shortage and inadequate of the smart grid. The blueprint and achieving methods of the smart electricity describes the design blueprint of the future smart electricity in Shanghai urban area, and the means and direction to realize, such as to adapt and promote clean energy development, realizing highly smart grid dispatching to meet the electric vehicle and other new electricity consumers of electricity service requirements, efficient use and life cycle management of grid assets, convenient interaction between power users and grid, grid management informationalization and delicacy and playing the role of value-added services potential of the grid infrastructure.

Using the method of mathematical modeling, the process of the emergence and spread of crown forest fires, as well as their termination in the presence of fire breaks and barriers, consisting of deciduous species, is studied. The Reynolds equations for turbulent flow were solved numerically, taking into account chemical reactions. The research was based on numerical solution of two dimensional Reynolds equations. The boundary-value problem is solved numerically using the method of splitting according to physical processes. A discrete analogue for the system of equations was obtained by means of the control volume method. The distributions of the fields of velocity, temperature, oxygen concentrations, volatile products of pyrolysis, combustion, and volume fractions of the condensed phase are obtained with time. The model made it possible to obtain in dynamics the contours of the spread of crown forest fires, which depend on the bulk and type of forest combustible materials, moisture content, wind speed and direction, etc. It was also possible to determine the dependence of the size of fire breaks and barriers on the above parameters, at which the crown fire stops spreading. Based on this data, we can estimate the minimum sizes of fire breaks and barriers, or their combined application, to stop the propagation of the flame front.

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) Forestry and Forest Products has developed a PC-based fire spread prediction application that can be used by fire control officers as an aid in strategic planning and resource allocation. This computer application, called Siro Fire, is a DOS protected mode application that incorporates several fire spread models that can be applied to the two major fuel types found in Australia-grass and forest. It uses GIS-derived geographic maps and digital elevation models to calculate the probable spread of a fire across the landscape and displays the results on a graphical representation of the map of the area of concern. The application is being used in the South Australian Country Fire Service as both an operational and training tool. This paper outlines the evolution of previous fire spread simulation software, the development of SiroFire and how SiroFire carries out fire spread simulations using existing fire spread prediction algorithms.

This paper puts forward the planning and configuration principle of the battery energy storage station(BESS) of the urban secure power grid, and establishes the full-life cycle economic model of the BESS based on the configuration requirements in urban secure power grid for the emergency power supply. Taking the maximum annual equivalent income as the objective function, an economic allocation model of the capacity of BESS for urban secure power grid based on improved particle swarm optimization algorithm(IPSO) was established to achieve the economic optimization of the capacity arrangement of energy storage power station while meeting the important load holding of the city under the disaster scenario of reliable support. At the same time, a reliability analysis model for energy storage capacity configuration results considering the impact of disasters is established to support the reasonable selection. Finally, the scheme comparison and optimization design are carried out based on the actual scenario of an urban secure power grid.

The aim of this paper is to propose a more practical mountain fire spread model for fire behavior prediction and management in Southwest forest area of China. These areas are covered mainly with spatial heterogeneous flammable forest and are characterized by undulating terrain and steep slopes. This model can produce more accurate fire propagation maps by combining CA (Cellular Automaton) framework with Wang Zhengfei fire physical velocity model in fine scale. Considering the inherent uncertainties of fire propagation, the model has been built on multi-dimension geophysical and environmental components and also sound knowledge of fire spread physical mechanism. Regarding small fuel patches as spatial homogenous cells, this approach makes it easier to generate higher level complex fire behavior maps from CA simple local rules and local behavior integrated with high resolution vegetation images, fine scale terrain maps and surface wind field. Because the model focuses primarily on the study of surface fire front propagation behavior, it attempts to simplify complex fuel modeling. Additionally, this Wang-Geophysical-CA model is able to analyze the time series spatial pattern of fire-front spread and model local behavior instead of the final fire spread pattern of the conventional approach. In this work, not only single influence verification tests have been made, but also simulation tests with multiple influences are carried out to demonstrate the capability of the model with fine scale vegetation maps, surface wind field, terrain, moisture content and man-made structures. Consequently, it is believable that the model predictions are in good agreement with experimental data for steady-state fire simulation. The proposed model helps to gain a greater understanding of the fire front spread local behavior and can quickly generate a sequence of complex fire front contours. It enables local managers to plan practical fire prevention activities in Southwest forest area of China as well as improve fire management skills, and will enhance the effectiveness of fire fighting strategies.

Wildfire risks are projected to increase in the future due to climate change, coupled with increased exposure along the wildland-urban interface (WUI) due to population growth and growing cities.This research presents a modelling framework for simulating potential risks posed by wildland fires to urban areas across the WUI via a multi-stage, loosely coupled approach:Stage 1 - Wildfire: Using Spark, user-defined equations determine fire spread behaviour (Miller et al. 2015). To calculate Rate of Spread (RoS) and Fireline intensities for New Zealand vegetation types, equations from Pearce (2005) are applied. These, along with localised climate data for current and future conditions, create wildfire scenarios. Flame heights and radiant heat flux (RHF) are spatially analysed at each time-step to assess risks to transport networks, critical infrastructure, and buildings near or outside urban areas along the WUI.Stage 2 – Building-to-building fire: With ignition points at urban boundaries defined, the second stage of the modelling framework uses a physics-based building-to-building fire spread model like that outlined in Himoto (2022) to simulate urban fire propagation over time. This, combined with wildfire model outputs, informs the risk assessment and micro-scale evacuation model.Stage 3 – Ensemble risk assessment:  Fire exposure from previous stages is used to assess risks to infrastructure and transportation networks. A method, adapted from Butler and Cohen (1998), defines RHF values and maps it to the transport network. This data informs the evacuation model, defining safe zones and low-risk evacuation corridors.Stage 4 – Evacuation modelling:  Building on work by Evans et al. (2020), the evacuation model integrates hazard outputs with micro-scale transport models to simulate evacuee movement under extreme scenarios. By incorporating movement restrictions and evacuee behaviours, it assesses risks to evacuees navigating the network.Together, these four stages provide a comprehensive risk assessment of wildfires and key insights for refining evacuation planning strategies.AcknowledgementThis project has received funding from the European Union's Horizon Europe research and innovation programme under the grant agreement number 101147385. Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or CINEA. Neither the European Union nor the granting authority can be held responsible for them.ReferencesButler, W, B., Cohen, D, J. (1998). Firefighter Safety Zones: A Theoretical Model Based on Radiative Heating International Journal of Wildland Fire 8(2) 73 – 77. https://doi.org/10.1071/WF9980073Evans, B., Chen, A.S., Djordjevic, S., Webber, J., Gómez, A.G., and Stevens, J. (2020). Investigating the 421 effects of pluvial flooding and climate change on traffic flows in Barcelona and Bristol. Sustainability, 422 12(6), 2330. https://doi.org/10.3390/su12062330Himoto, K. (2022). Large Outdoor Fire Dynamics – Fire Spread Simulation (pp 333 – 367). 1st Edition. CRC Press. http://dx.doi.org/10.1201/9781003096689-10Miller, C., Hilton, J., Sullivan, A., Prakash, M. (2015). SPARK – A Bushfire Spread Prediction Tool. In: Denzer, R., Argent, R.M., Schimak, G., Hřebíček, J. (eds) Environmental Software Systems. Infrastructures, Services and Applications. ISESS 2015. IFIP Advances in Information and Communication Technology, vol 448. Springer, Cham. https://doi.org/10.1007/978-3-319-15994-2_26Pearce, G. H. (2025). Appendix 3: Sub-contracted Report: Fuel Load and Fire Behaviour Assessments for Vegetation within LCDB2

In this paper, we studied the spreading of canopy forest fires in the presence of fire breaks and barriers consisting of hardwood trees by mathematical modeling. Mathematically, this problem is reduced to solving Reynolds equations for a turbulent flow with allowance for chemical reactions. The control volume method was used to obtain a discrete analogue. Using numerical calculations, we obtained distributions of the fields of velocity, temperature, oxygen concentrations, volatile products of pyrolysis and combustion, and volume fractions of the condensed phase. The modeling allowed obtaining contours of the spread of canopy forest fires that depend on the stock and types of forest combustible materials, moisture content, wind speed and direction, etc. We were also able to determine the dependence of the size of fire breaks and barriers on the above parameters, at which a canopy fire stops spreading.

Wildfires are an increasing threat in Mediterranean regions, where extreme fire weather and long-term fuel accumulation are driving more frequent and severe events. In this context, fast and reliable fire spread simulations are essential to support both risk mitigation planning and real-time emergency management. PROPAGATOR is a stochastic Cellular Automata (CA) wildfire spread simulator designed to generate ensemble-based fire spread forecasts. The model, currently available as both an online application and open-source software, operates within a raster-based framework in which each cell is described by static attributes (e.g. fuel type, topography) and dynamic drivers (e.g. wind, fuel moisture). Fire propagation is modelled through a stochastic contamination process between burning and unburned cells, allowing the production of probabilistic maps of fire spread, as well as statistics on rate of spread and fireline intensity. PROPAGATOR also includes the capability to simulate the spotting phenomenon and suppression actions such as water drops or firebreak construction, making it suitable for both operational decision support during active fires and pre-event risk mitigation analyses. A current limitation of operational applications of PROPAGATOR is its focus on surface fire propagation, with no explicit representation of vertical fuel structure or transitions to crown fire. Crown fires, however, are characterized by higher spread rates, greater energy release, and increased unpredictability, with major implications for suppression effectiveness and ecological impacts. To address this limitation, an enhanced version of PROPAGATOR has been developed by extending the model to a quasi-three-dimensional (2.5D) representation of fuels, enabling the simulation of crown fire processes within the stochastic CA framework. The proposed Crown Fire Module relies on established empirical and semi-empirical formulations for crown fire initiation and spread that are compatible with a cellular automata approach. Crown fire initiation is governed by surface fireline intensity and crown base height, while crown fire rate of spread depends primarily on canopy bulk density and fire behaviour. These mechanisms have been integrated into the propagation rules of PROPAGATOR, allowing dynamic transitions between surface and crown fire behaviour within a probabilistic modelling framework. The implementation of these processes requires detailed information on both surface and canopy fuel structure and characteristics, which remains challenging at operational scales. To address this issue, we investigated the use of UAV-based LiDAR remote sensing to derive key fuel structure parameters using semi-automatic algorithms available in the literature. This approach offers a balance between spatial detail and areal coverage that is suitable for operational wildfire applications. A pilot study conducted in the Venafro area (Molise, Italy), based on a past wildfire event with a comprehensive dataset describing fire evolution, provided high-resolution inputs to test the enhanced model. By explicitly simulating surface-to-crown fire transitions, the upgraded version of PROPAGATOR aims to improve decision support for wildfire risk management, supporting applications ranging from fuel treatment planning to operational response under extreme fire weather conditions.

Climate change causes more extreme droughts and heat waves in Central Europe, affecting vegetative fuels and altering the local fire regime. Wildfire is projected to expand into the temperate zone, a region traditionally not concerned by fire. To mitigate this new threat, local forest management will require spatial fire hazard information. We present a holistic and comprehensible workflow for quantifying fuels and wildfire hazard through fire spread simulations. Surface and canopy fuels characteristics were sampled in a small managed temperate forest in Northern Germany. Custom fuel models were created for each dominant species (Pinus sylvestris, Fagus sylvatica, and Quercus rubra). Canopy cover, canopy height, and crown base height were directly derived from airborne LiDAR point clouds. Surface fuel types and crown bulk density (CBD) were predicted using random forest and ridge regression, respectively. Modeling was supported by 119 predictors extracted from LiDAR, Sentinel-1, and Sentinel-2 data. We simulated fire spread from random ignitions, considering eight environmental scenarios to calculate fire behavior and hazard. Fuel type classification scored an overall accuracy of 0.971 (Kappa = 0.967), whereas CBD regression performed notably weaker (RMSE = 0.069; R2 = 0.73). Higher fire hazard was identified for strong winds, low fuel moisture, and on slopes. Fires burned fastest and most frequently on slopes in large homogeneous pine stands. These should be the focus of preventive management actions.

Fires caused by cables occur frequently in mines, which endanger the safety of workers. To explore the characteristics of a multilayer cable fire in a mine tunnel, multilayer cable fire simulations were carried out using the Fire Dynamics Simulator (FDS). The influence of cable tray spacing, ignition position, and tunnel ventilation speed on the characteristics of the fire were studied. The results showed that these factors change the amount of contact between the cable and air, the heat accumulation, and the heat transfer by the flame interaction between the cables. It was also noted that increasing the spacing or wind speed both made the peak of heat release rate (PHRR) initially increase and then decrease. The influence of wind speed on the cable burnout rate in the upstream and downstream sides of the fire source was not consistent, and the wind speed had a sensitive effect on the cable burn out rate in the upstream side of the fire source. The higher the ignition position was, the longer the arrival time of PHRR was and the slower the fire developed. There was a higher burn velocity close to the ceiling. The cable hooks obstructed the cable fire. This study provides a theoretical basis for cable fire prevention and control in mine tunnels.

Enhancing resilience in urban utility tunnels power transmission systems: Analysing temperature distribution in near-wall cable fires for risk mitigation

Urban power grid is a typical load center. According to the operational characteristics and structure of urban power grid, a complete set of urban grid operation risk index system where the calculation methods of each affiliated index is given, is proposed from the point of equipment direct loss, grid structure integrity failure, grid security margin and power grid load loss. On this basis, the paper makes use of Analytic Hierarchy Process (AHP) to synthesize the affiliated index and draw the total risk index of power system to assess the risk level of power grid. Taking the Polish power grid as an example, the paper calculates and analyzes each affiliated index and the total risk index based on a preset contingency, and verifies the feasibility of the proposed risk assessment index system and methods. And the indices computed are for use by operators and operational engineers in the control room to assess system security levels as a function of existing and near-future network conditions.