Fire Problem Research Articles

A Multi-Scale Analysis of the Fire Problems in an Urban Utility Tunnel

Building utility tunnels has been widely adopted as an important solution for the sustainable development of cities, but their unique fire problems have not attracted enough attention to date. With the purpose of preliminarily understanding the fire phenomena in a utility tunnel, this study performed a comprehensive analysis, including the burning behaviour of accommodated cables, hot gas temperature field and enhanced fuel burning rates based on bench-scale, full-scale and model-scale fire tests. The critical exposed radiative heat flux for the 10-kV power cable to achieve complete burning was identified. The whole burning process was divided into five phases. The cable’s noteworthy hazards and dangerous fire behaviours were also examined. The two-dimensional (2D) gas temperature fields and longitudinal maximum temperature distributions were investigated carefully, after which a versatile model was derived. The model predicted the maximum temperature attenuation of both upstream and downstream flows reasonably well. Finally, the phenomenon of enhanced fuel burning was explored. A multivariate cubic function that considers the global effects of relative width, height and distance was further proposed to estimate the enhancement coefficient. The current findings can provide designers and operators with valuable guidance for the integrated promotion of utility tunnels’ fire safety level.

Elderly at Home: A Case for the Systematic Collection and Analysis of Fire Statistics in Spain

At the present time, there is no nation-wide, systematic approach to collecting, analyzing and presenting fire loss data in Spain. This makes it very difficult to understand the fire problem in general, and more specifically with respect to vulnerable populations, such as the elderly. As first steps to overcome the lack of a nationally populated and managed fire incident database, a methodology for collecting fire data, based on information extracted from the media, was developed. This approach is modeled in part on the Fire Incident Data Organization system from the National Fire Protection Association in the United States, which identifies significant fires through a clipping service, the Internet and other sources. For the initial Spanish database, selected variables were chosen from similar statistics gathered in other countries. The variables are related to the place and moment of the fire, its causes and consequences, the building typology and state, and the fatal and non-fatal victims involved, among other factors. In the initial data set, data concerning residential fires occurred between January 2016 and December 2016 was collected, and variables were analyzed. An initial focus was to identify the risk factors for one of the most vulnerable groups in case of fire, the elderly people. The development of this first-ever nationally-representative database of fire incidents in Spain is overviewed, and analysis of elderly population in dwelling fires is presented as a study case that represents the value and need of such a national database in Spain.

Forest arson in Portugal: criminal behaviour and gender differences

Introduction/Background: Firesetting refers to the intentional act of use of fire with the purpose of damaging property. Starting a fire not only reveals an antisocial behavior but has also serious social economic implications for society. Although there are other possible causes for fires in general such as natural hazards, improper use of fire or accidental structural problems, intentional forest fires poses a serious problem and represents 13 to 20% of the causes of firesetting [1,2]. The incendiarism behavior can be defined by a set of risk factors that explain recidivism: the firesetter and setting of fire characteristics and the motivations associated to the committed crime. The aggressor gender is a distinguished variable in this characterization, since this behavior is seen more frequently in males (90%). The females associated with this type of crime have more specific traits, integrating an homogeneous criminal typology. The objective of this presentation is to show results of a comparative study based on a sample of Portuguese arsonists of both genders, in forest context, between 2015 and 2017. Methods: We studied 260 individuals, 25 were female (9.6%) and 235 were male (90.4%), between 14 and 86 years old. The variables were collected by the instrument “Summary Sheet - Risk Factors for Recidivism” (EPJ, 2015). The instrument is organized in three sections: 1) Offenders general characteristics (age, sex, education and profession), 2) Firesetting typology, 3) Criminal behaviour description and 4. Psychological and social firesetter characteristics. Collateral information was recollected through the consultation of the SPO (Judiciary Police Online Research System), for confirmation of sociodemographic data and criminal records. All work in this paper was conducted with the formal approval of the subjects and it follows the principles of the Declaration of Helsinki. Results: The results confirm that female show a more homogenous criminal typology than men. In general, women are represented in two main profiles: Profile A - Retaliatory Instrumental and Profile C- Clinical History, contrary to men that are represented in four criminal profiles (Profile A- Retaliatory Instrumental, Profile B- Benefic Instrumental, Profile C- Clinical History and Profile C1- Fire Attraction). Both genders share characteristics like: few social skills; difficulties in solving problems, in personal relationships as in integration in community; sustenance or unspecialized professions; type of burning area, time of occurrence and devices used. Concerning problems of psychological nature, men had more problems related to alcohol consumption than women, and women reported more mental health issues than men. Regarding motivation, female are essentially expressive, associating firesetting to anger and revenge drives, while male motivations are divided in two: expressive (78.44%) and instrumental (26.95%). Discussion and conclusions: The firesetters could be differentiated in terms of expressive or instrumental motivations [3]. Many of the incendiary behaviors presented by women are associated with situations of depression, family problems involving relationship problems and parental responsibilities conflicts. Women also may present no attraction by the fire and low levels of alcohol consumption when compared with men (2% in the moment of crime).

Study on Intelligent Management System of Electrical Safety

This paper introduces the present situation of electric fire protection, expounds the concept of fire early warning, briefly introduces the research work being carried out in this field, introduces the intelligent management system of electric safety developed recently, and on this basis, analyzes the fire prevention and control problems that are expected to be solved by the electric safety intelligent management system for further study. To enhance the level of electrical fire protection in China, a new prevention and control method is proposed.

JUSITFICATION OF DRY CHEMICAL POWDERS TESTING PROCEDURE

The analysis of the problem of extinguishing fires of magnesium and its alloys is carried out. The urgency of studying the problem is confirmed by the fact that during the extinguishing of class D fires there are factors that can complicate the quenching process. Often, these metals actively react with water, which leads to an even greater spread of the fire and even an explosion. Therefore, special fire extinguishers, which have passed the proper test, are more effective in locating the fire and prevent the burning of the powder to form the "tongues" of the flame. In Ukraine, there is no method for testing the effectiveness of fire extinguishants of special purpose for the extinguishing of class D fires. The normative documents have been analyzed, which specify the procedures for testing extinguishing fire-extinguishing special-purpose fire extinguishing class D. Specifically: the methods are described in the international standard ISO 7165: 2017 «Fire fighting – Portable fire extinguishers – Performance and construction» and GOST 53280.5-2009 Fire fighting systems automatic. Extinguishing agents.
 Both methods have a number of shortcomings that need to be addressed when creating a Ukrainian fire test method for extinguishing fire extinguishing class D, namely: the dimensions of the metal frame made of sheet steel with a side (500 ± 10) mm, height (150 ± 5) mm for testing with magnesium chips are small; Not specified quantity of gasoline necessary for the rise of magnesium; The gas or oxygen torch used to dissolve magnesium does not provide full-value combustion throughout the area, but only creates separate cells of ignition.
 A draft methodology has been developed that determines the fire-extinguishing efficiency of powdered powders used in Ukraine. The required amount of fuel for burning magnesium and its alloys is determined. It was ascertained that for the firing of magnesium chips it is necessary to use at least 127 grams of gasoline of the mark A 92.
 Key words: test method, fire extinguishers of special purpose, extinguishing of fires of magnesium alloys

Fire resistance evaluation through artificial intelligence - A case for timber structures

With the ever-growing surge of new technologies, there seems to be an ongoing inertia towards integrating automation and cognition into various engineering applications. Despite a number of initiatives, and oddly enough of all civil engineering sub-disciplines, the structural fire engineering and fire safety community continues to embrace a classical stance to tackle the problem of fire. In support of growing demands to adopt performance-based solutions, this paper showcases the potential of integrating Artificial Intelligence (AI) as a unique technology to assess performance and fire resistance of structures. More specifically, this study sheds light on the proper use of AI to derive temperature-dependent material models for wood, together with simple expressions that can be used to trace thermo-structural response of timber elements/components (i.e. floor assemblies, beams, columns, and connections). These expressions comprehend the naturally complex temperature-induced physio-chemical changes to timber properties, including creep and charring, and hence do not require input of such properties nor special computing software. The outcome of this study clearly shows the merit of utilizing AI to modernize fire resistance evaluation given that the developed AI-models have high degree of perception (i.e. learn from past behaviors) and ability to improve their prediction capability through independent and unsupervised learning.

ЕКОЛОГІЧНА ОБУМОВЛЕНІСТЬ СУЧАСНОГО СТАНУ ЛІСОВИХ КУЛЬТУРФІТОЦЕНОЗІВ КРИВОРІЖЖЯ

Досліджено лісові культурфітоценози Криворіжжя, які репрезентують усі основні різновиди штучних деревних насаджень регіону. Сучасний стан лісових культурфітоценозів характеризується несформованою вертикальною структурою (в більшості випадків відсутні яруси підліску та чагарників); ущільненими посадками першого та другого ярусів; невисокими значеннями запасів стовбурної деревини; ослабленим та сильно ослабленим життєвим станом деревостану.

Efficient uncertainty quantification method applied to structural fire engineering computations

Probabilistic Risk Assessment methodologies are gaining traction in fire engineering practice as a (necessary) means to demonstrate adequate safety for uncommon buildings. This induces a need to apply uncertainty quantification to structural fire engineering problems. Yet, the combination of probabilistic methods and advanced numerical fire engineering tools has been limited due to the absence of a methodology which is both efficient (i.e. requires a limited number of model evaluations) and unbiased (i.e. without prior assumptions regarding the output distribution type). In this paper, the recently proposed MaxEnt method is combined with the dedicated structural fire engineering software SAFIR to evaluate the ability of the method to achieve efficient, unbiased assessments of structural fire performance. The case studies include the probability density function (PDF) of (i) the standard fire resistance of a composite column; (ii) the load bearing capacity of a composite floorplate exhibiting tensile membrane action, after 90 min of standard fire exposure; (iii) the load bearing capacity of the same composite floorplate, considering a parametric fire exposure including cooling phase; and (iv) the maximum temperature reached in a protected steel element under realistic fire exposure. In the first application, the MaxEnt PDF correctly and efficiently captures the distribution obtained using Monte Carlo Simulations. The floorplate example under parametric fire exposure shows the true strength of the MaxEnt method as an unbiased assessment, as different failure modes are observed in the cooling phase resulting in an irregular shape of the load-bearing capacity PDF. For this case, reliance on a traditional assumption of lognormality for the capacity would result in an overestimation of the capacity at lower quantiles. The last case study yields a bi-modal output due to the physics-based duality between localized (traveling) and post-flashover fire development. While the MaxEnt captures this bi-modality, it does not accurately reproduce the distribution obtained by Monte Carlo Simulation. Limitations of the MaxEnt method and needs for further research are discussed at the end of the paper.

Hybrid Data Regression Model Based on the Generalized Adaptive Resonance Theory Neural Network

The Generalized Adaptive Resonance Theory (GART) model is a supervised online learning neural network based on an integration of Adaptive Resonance Theory (ART) and the Generalized Regression Neural Network (GRNN). It is capable of online learning, and is suitable for undertaking both classification and regression problems. In this paper, we further enhance GART (EGART) with four improvements to formulate a new EGART model. Three operating strategies for the EGART model to undertake regression problems are suggested. The first operating strategy is a fully online learning EGART model. The second operating strategy involves Ordering Algorithm for determining the presentation sequence of training samples during the initial training of EGART model. This strategy is considered as offline learning because a set of data samples must be available for the Ordering Algorithm to compute the best presentation sequence (hereinafter denoted as Ordered-EGART). The third operating strategy aims to demonstrate online learning capability of EART model (the first operating strategy) can still be resumed after training on the Ordered-EGART. It is most suitable for applications with a set of ready data samples and their sequences are predetermined by Ordering Algorithm prior to training of EGART model in offline mode, and triggers online learning when more new data samples become available (hereinafter denoted as IO-EGART). A series of experiments with five benchmark data sets from various application domains is conducted to assess and compare the effectiveness of the EGART model and three operating strategies with those of other methods published in literature as well as two fire safety engineering problems, i.e., predicting the thermal interface height in a single compartment fire and evacuation times in the event of fire. The results and comparisons with other approaches positively demonstrate the efficacy and applicability of EGART model as a useful data regression model for tackling fire safety engineering problems.

Incendios forestales en Galicia y Portugal: una perspectiva histórica

This study looks at the impact of forest fires in Galicia and Portugal from a comparative point of view. The first part deals with the common history of both regions until the Independence of Portugal emphasizing the pollen and anthracological analyses. The second part examines the problems of forest fires involving the two countries, focusing on the Modern Age, particularly on the influence of activities such as herding, land clearing, charcoal making, and shipbuilding. The influence of new forestry on the techniques for fighting forest fires is highlighted, especially the impact of the disintegration and depopulation of rural areas as a starting point for the extensive wave of forest fires we see today. Finally, it is suggested that a new generation of forest fires is being triggered by climate change, among other causes.

Recognition of distribution of the center for diffusion of snares as a result of heating the stroke of the equipment during the fire of the fire problem

The article gives a brief analysis of the use of artillery in the course of an anti-Eurasian operation in the east of Ukraine. Artillery units were involved in a significant number of fire missions with a large expenditure of ammunition. Most artillery missions are performed to defeat unobservable targets, the destruction and suppression of which, as a rule, requires a large amount of ammunition and considerable fire time, which leads to the heating of gun barrels. As a result of the heating of the barrels, the initial velocity of the projectiles changes, the scattering of projectiles from the point of aiming at a range that does not allow for which may lead to a decrease in the effectiveness of the fire, and in some cases to the non-fulfillment of the fire task. The artillery units and subunits received new and modernized weapons, for which there are no tables for determining the deviations of the initial velocity of shells from the tabulated value with the help of ABS-1 and the Table of Accounting, mixing the center of scatter of projectiles as a result of the heating of the barrel. Taking into account the combat experience of the use of artillery units and subunits, and on the basis of the conclusions drawn in the Rules of shooting and fire control of ground artillery of 2018 (PSiUO NA), amendments to the section on ballistic training for the need to take into account the corrections for the heating of gun barrels are missing, but there is no procedure for determining them.The article details the procedure for the work of the division's officials in organizing settlements and recording corrections for the heating of gun barrels during the preparation of installations for shooting and during the execution of fire missions. The example of the 152 mm cannon 2A36 divisions presents the procedure for using tables and formulas in the calculations, and also shows the magnitude of possible corrections for range as a result of the heating of the barrels and the displacement of the center of the projectile scattering from the aiming point. The need to provide artillery units with tables for determining the total deviation of the initial speed from the tabulated value using ABS-1 and tables for determining the number of conditional shots for different charge numbers, initial speed deviations and the ballistic coefficient for all artillery pieces that are in service with artillery units of the Armed Forces forces of Ukraine.

The solution of fire safety problems under a design stadia with computer fire and evacuation simulation

It is shown in the paper how fire evacuation simulation can be applied to check fire safety and find safe conditions under design stadia of the building. Mathematical background of fire and evacuation simulation is presented. An ice stadium is considered as an example.

MODELING OF PARAMETERS FOR FOREST FIRE RISK ZONE MAPPING

Abstract. Forest fire has been regarded as one of the major reasons for the loss of biodiversity and dreadful conditions of environment. Global warming is also increasing the incidence of forest fire at an alarming rate. That’s why, one need to understand the complex biophysical parameters, which are responsible for this disaster. As it is difficult to predict forest fire, fire risk zone map can be useful for combating the forest fire. So the main aim of this study is to generate a Fire risk model to map fire risk zone using Remote Sensing & GIS technique. Pauri Garhwal District, located in Uttarakhand, India, has been selected for this study as it continually faces the problem of forest fire. Landsat-8 data of 18th April, 2016 have been used for land use land cover mapping. Slope and other information have been derived from topographic maps and field information. For thematic and topographic information analysis ArcGIS and ERDAS Imagine software have been used. Forest fire risk model was generated by using AHP method, where each category was assigned subjective weight according to their sensitivity to fire. Three categories of forest fire risk ranging from very high to low were derived. The generated forest fire risk model was found to be in strong agreement with actual fire-affected sites.

Incêndios florestais, o contributo da GNR para o sucesso da missão. Lições a retirar dos incêndios de 2017

A partir de 2006, a GNR passou a ter uma intervenção muito mais ativa na problemática dos incêndios florestais, sendo indiscutível que trouxe uma nova dinâmica à proteção e socorro, tendo assumido um dos três pilares do Sistema da Defesa da Floresta Contra Incêndios (SDFCI) e passando a atuar no designado pilar do “combate, rescaldo e vigilância pós incêndio”, sendo a única instituição nacional com intervenção em dois pilares do sistema o que lhe permite agir no âmbito do “safety” e “security”.Os grandes incêndios rurais da atualidade, revelaram que Portugal enfrenta um problema estrutural de ordenamento do território que constitui uma grave ameaça à segurança das populações, tendo sido constatado que há lacunas e lições a reter. Futuramente pretende-se um maior envolvimento dos cidadãos, reforçando a consciência coletiva de que a proteção e a segurança são responsabilidades de todos, uma maior participação das autarquias locais, tudo com a finalidade de evitar comportamentos de risco e adotar medidas de autoproteção.

Analysis of Controlling Wireless Temperature Sensor for Monitoring Peat-Land Fire

The problem of forest and peatland fires in Riau has become main topic to prioritize its revamping. Land and forest fires in Riau until reached 3,700 hectares area, happened in some last years,.Forest and peatland fires occured in the majority of districts in Riau Province, from low category of 4 hectares until 2,800 hectares. This researchdiscusses aboutanalysis of controlling wirelessTemperature Sensor for monitoring Peat-Land fire by using LM35 Temperature Sensor, Transmitter-Module (HC-12), Receiver-Module (HC-12), Arduino-ProMini to produce outputs on LED, LCD, Buzzer. Detector of Peat-Land fire works when it is burning, so heat will spread through aluminium stalk and be read by Temperature-Sensor1 upto Temperature-Sensor4. Output of each sensor is sent to each control block of Arduino-ProMini in Transmitter-Module(FU1–FU4). From Arduino-ProMini, it is sent toReceiver-Module(FU5). Receiver-Module only receives one data from Transmitter-Module in one time. Every data is received by Receiver-Module goes to Arduino-ProMini, processed to produce outputs on LCD that shows ID of FU1–FU4, Peat-Land Status, temperature of Peat Land. If LED is Green, Peat-Land not burned, LED shows SAFE Condition, Buzzer Off. If LED is Yellow, Peat-Land burned underground, LED shows BE-CAREFUL Condition, Buzzer On. If LED is Red, Peat-Land burned on the ground, LED shows DANGER Condition, Buzzer On. Temperature 0°C–21.9°Cis SAFE Category because Peat-Land not burned. Temperature 22°C–28.4°Cis BE-CAREFUL Category because Peat-Land burned underground. Temperature 28.4°C–50°Cis DANGER Category because Peat-Land burned on the ground. This equipment works as its frame work.

Simulations of a Turbulent Line Fire with a Steady Flamelet Combustion Model and Non-Gray Gas Radiation Models

The general objective of this project is to develop an accurate combustion and radiation modeling framework for high-fidelity large eddy simulations (LES) of well-controlled turbulent laboratory-scale fires for which the fuel composition and fuel oxidation chemistry are known. This modeling framework is aimed at providing a solid basis for the development and validation of engineering-level models used in simulations of real-world fire problems for which the sources of fuel are diverse, complex, and in many cases, poorly characterized. The combustion model features a library of flamelet solutions corresponding to one-dimensional, steady, laminar, counterflow diffusion flames simulated with specialized software, a chemical kinetic mechanism and an equi-diffusive molecular transport model (i.e., unity Lewis numbers). Two different flamelet libraries are considered here: a first library generated with a solver called libOpenSMOKE and a detailed chemical kinetic mechanism developed for C1-C3 combustion chemistry and a second library generated with a solver called FlameMaster and the GRI-Mech v3.0 chemical kinetic mechanism developed for methane combustion chemistry. The radiation model features a banded Weighted-Sum-of-Gray-Gases model but (so far) no description of subgrid-scale turbulence-radiation interactions (TRI). This modeling framework is incorporated into a LES solver developed by FM Global and called FireFOAM, and is evaluated in simulations of a two-dimensional, plane, buoyancy-driven, methane-air, turbulent diffusion flame experimentally studied at the University of Maryland. The configuration corresponds to an intermediate validation step in our model development strategy without the complications of flame extinction. The flame structure is characterized by new micro-thermocouple measurements of the temporal mean and root-mean-square gas temperatures. Comparisons between simulated and measured temperatures show significant discrepancies that are explained by the large values of the width of the presumed probability density function (PDF) representing subgrid-scale variations of mixture fraction and by the absence of a model for subgrid-scale TRI.

Wildfire risk and its perception in Kabylia (Algeria)

Abstract: This research aims to study wildfire perception by residents living in Wildland Urban Interface (WUI) in Kabylia (Algeria). We conducted an exploratory qualitative survey contacting 254 randomly selected individuals in eight hamlets of the Mizrana forest. Face-to-face questionnaires were administered to understand the fire risk problem. Respondents think that their homes are not exposed to fire risk and perceive their hamlets are protected against wildfires; on the contrary, they perceive their property (fields, livestock, olive trees, etc.) as exposed to fire risk. The vast majority of respondents declare to know how to defend themselves in the case of a fire event, using water and hand tools. Residents mainly use fire for stubble burning and disposal of domestic waste. Their skill in using fire as a land management tool respectively comes from their fathers, grandfathers and mothers. Results show the necessity of making resident more aware of the risks that wildfires pose to them. A culture of risk needs to be developed within the territory to limit vulnerability and the likelihood of destructive fires.

Fire Source Range Localization Based on the Dynamic Optimization Method for Large-Space Buildings.

This paper is concerned to the fire localization problem for large-space buildings. Two kinds of circular fire source arrangement localization methods are proposed on the basis of the dynamic optimization technology. In the Range-Point-Range frame, a dynamic optimization localization is proposed to globally estimate the circle center of the circular arrangement to be determined based on all the point estimates of the fire source. In the Range-Range-Range frame, a dynamic optimization localization method is developed by solving a non-convex optimization problem. In this way, the circle center and the radius are obtained simultaneously. Additionally, the dynamic angle bisector method is evaluated. Finally, a simulation with three simulation scenes is provided to illustrate the effectiveness and availability of the proposed methods.

Numerical study of propagation of forest fires in the presence of fire breaks using an averaged setting

The forest fires spread in the pine forests have been numerically simulated using a three-dimensional mathematical model. The model was integrated with respect to the vertical coordinate because horizontal sizes of forest are much greater than the heights of trees. In this paper, the assignment and theoretical investigations of the problems of crown forest fires spread pass the firebreaks were carried out. In this context, a study ( mathematical modeling) of the conditions of forest fire spreading that would make it possible to obtain a detailed picture of the change in the temperature and component concentration fields with time, and determine as well as the limiting condition of fire propagation in forest with these fire breaks.

Degradation of Out-of-plane Initial Stiffness of Steel-concrete Walls Exposed to Fire

Steel-concrete (SC) walls, as a main lateral resisting system in nuclear power plants, have serious fire resistance problem because of their exposed steel faceplates. The out-of-plane stiffness of SC walls will degrade when exposed to fire, which has significant influence on the mechanical performance of the composite walls and even the whole structure. In this paper, a finiteelement (FE) model was developed to simulate thermo-mechanical coupling behavior of SC walls exposed to fire. One conducted ISO-834 standard fire test and two reported thermal and mechanical loading tests were assembled to verify the developed FE model. Based on the validated FE model, numerical experiments of 15 SC walls in fire exposure durations of 0~3 h were conducted to investigate the effect of steel arrangement and geometrical size on the out-of-plane initial stiffness of SC walls under elevated temperatures. Numerical results indicate that the out-of-plane initial stiffness of SC walls under ambient temperature is mainly influenced by steel faceplate thickness and section depth, while the initial stiffness degradation under elevated temperature is mainly influenced by fire exposure duration or surface temperature of exposed steel faceplate. Then, two equations were proposed to predict the out-of-plane initial stiffness of SC walls exposed to fire. The predicted results agree well with the test and numerical results, which demonstrates that the proposed equations can be used to estimate the damage of SC walls in fire.