Fire Extinguishing Methods Research Articles

Research and application of continuous and precise nitrogen injection fire extinguishing technology in coal mines

To overcome shortcomings in traditional nitrogen injection fire prevention techniques, such as discontinuous nitrogen distribution, poor inerting effects, and severe waste of pipeline resources, a method for continuous and precise nitrogen injection fire extinguishing was proposed. To implement this method, this study utilizes FLUENT, FLAC 3D simulations, and principles of elasticity to determine the process and dynamic parameters of nitrogen injection. This information guides the selection, design, and manufacturing of equipment components, leading to the development of a novel “rotating towing type” continuous and precise nitrogen injection fire extinguishing equipment. Taking Wenzhuang 15,102 working face as an example, the inerting effect was compared and analyzed by using CO, Graham coefficient R2 (ΔCO/ΔO2), R3 (ΔCO/ΔCO2) and other quantitative indicators. The findings revealed following results: after deploying this equipment, there was an approximate 70 % reduction in CO concentration. Comparatively, R2 in the extraction area decreased by 45 % compared to the 0.38 % observed in the buried pipe nitrogen injection process. Similarly, the R3 values for the gob and upper corner were reduced by about 56 % and 60 %, respectively. These substantial improvements highlight the superior efficacy of the continuous and precise nitrogen injection fire extinguishing method for nitrogen injection and fire suppression in gobs.

FIRE FIGHTING ROBOT

The increasing frequency and intensity of fire incidents worldwide is maximizing without determined solution hence, there is a growing need of solution for fire extinguishing methods. This system is operated manually with wireless connection, navigates through complex environments to identify and combat fire in diverse setting. Its mobility is enhanced by all terrains such as rough landscapes detecting the obstacle and moving beside to reach the fire accident spot. It is equipped with real time communication capabilities, enabling it to communicate with the coordinator and emergency response team. This advanced system would shape future for efficient and effective firefighting operations by reducing response time, enhancing safety. Keywords – Fire fighting robot, flame sensors, smoke sensor, temperature sensor, motors, water pump, ESP32 camera, ESP32 microcontroller.

Axial compressive performance of water cooling high strength concrete-filled steel tubular columns after high temperature

The degradation of mechanical properties of high strength concrete-filled steel tubular columns after fire is one of the possible causes of building collapse. Meanwhile, water cooling is the most commonly used fire extinguishing method. This paper presents 20 high strength concrete-filled steel tubular(HSCFST) columns after high temperature under axial compression, including 14 water cooling HSCFST. With the maximum temperatures, cooling methods, constant temperature durations and concrete strengths as variation parameters, the axial compressive performance of HSCFST was discussed. The results show that with the increase of temperature, the peak load, initial stiffness and energy absorption of HSCFST increase firstly and then decrease while the ductility coefficient is contrary. The average ultimate bearing capacity of water cooling HSCFST after being exposed to 800 °C degrades by 35.5% in comparison to that of specimens at 20 °C. The properties of water cooling specimens were improved compared with natural cooling specimens. The higher concrete strength specimens show better fire resistance. A bearing capacity calculation model of HSCFST was proposed, which considered the different cooling methods and the materials degradation. The calculation results were in good agreement with test results.

Forest Fire Spread Simulation and Fire Extinguishing Visualization Research

There are three main types of forest fires: surface fires, tree crown fires, and underground fires. The frequency of surface fires and tree crown fires accounts for more than 90% of the overall frequency of forest fires. In order to construct an immersive three-dimensional visualization simulation of forest fires, various forest fire ignition methods, forest fire spread, and fire extinguishing simulation exercises are studied. This paper proposes a lightweight forest fire spread method based on cellular automata applied to the virtual 3D world. By building a plant model library using cells to express different plants, and by building a 3D geometric model of plants to truly capture the combustion process of a single plant, we can further simulate forest-scale fire propagation and analyze the factors that affect forest fire spread. In addition, based on the constructed immersive forest scene, this study explored various forms of fire extinguishing methods in the virtual environment, mainly liquid flame retardants such as water guns, helicopter-dropped flame retardants, or simulated rainfall. Therefore, the forest fire occurrence, spread, and fire extinguishing process can be visualized after the interactive simulation is designed and implemented. Finally, this study greatly enhanced the immersion and realism of the 3D forest fire scene by simulating the changes in plant materials during the spread of a forest fire.

An Experimental Study on the Separation Distance to Prevent Impairment of Sprinkler Head Spray

Sprinkler facilities are a reliable fire-extinguishing method, but a spray barrier around the sprinkler head has a significant impact on fire suppression and control. Rule 13 from the National Fire Protection Association aims to set fire safety standards but might reduce sprinkler reliability because of confusion about the rule application. The sprinkler height should be up to three times the width of an obstacle, which is confused with an obstacle’s maximum size. Therefore, this study conducted a spray distribution experiment by adjusting the separation distance between the bottom-up head and the spray barrier to between 1 and 8 times the outer diameter. As a result, the performance standards relating to the amount of water collected satisfied the reference curve at a separation distance of 7 times the outer diameter when the radiation pressure was 0.1 MPa.

Secondary Thermal Deformation Characteristics of Stiffened Plate Exposed to Fire

The material and structural thermal deformation characteristics of a steel stiffened panel under various fire-extinguishing methods were investigated experimentally. Propane gas was used to generate jet fires for steel stiffened panels widely used as offshore installation structures. The characteristics of the initial imperfection (initial deflection and residual stress) occurring during fabrication were measured and analyzed before and after the fire experiment. In addition, the serviceability limit values were analyzed in terms of the maximum and permanent defections of the steel stiffened plate. The experimental results can be used as basic data for establishing various maintenance/ retention systems in the event of fire accidents on offshore installations.

Противопожарная защита резервуаров с метанолом самовспенивающейся газоаэрозоленаполненной пеной

Polar liquids including methanol are widely used in various industries. It has unique physical and chemical properties: extreme fire and explosion hazard, corrosive activity, high toxicity. These properties determine the complexity of its extinguishing. In Russia, there is practically no normative base for the design, construction, and repair of tanks where methanol is stored. In the available recommendations for extinguishing methanol fires by «soft» method the normative intensity of alcohol-resistant foam supply to the fire source is underestimated. Alcohol-resistant foam concentrates such as AFFF/AR, FFF/AR, S/AR allow to ensure reliable extinguishing of polar liquids. To do this, it is required to determine the method of supplying the foaming agent and its standard intensity when extinguishing methanol in the tanks. Thermophysical properties of the methanol combustion (heat fluxes, burnout rate, heat release rate) determine the possibility of developing methods for its extinguishing on the model fire seats. For these purposes, the pallets with a diameter of more than 3 m can be used with a side thickness of 6 mm. To extinguish methanol, it is proposed to use a low-expansion self-foaming gas-aerosol filled foam with a standard flow rate of 0.25 l/(m2·s). Specific consumption of the fire extinguishing agent was determined: for methanol, it should be 30 l/m2 with an extinguishing time of 120 s. Foam generation can take place without the use of traditional foam generators with the help of self-contained solid fuel fire extinguishing installations. When using them, the problem of corrosion resistance of foam generating equipment is solved, and the «soft» fire extinguishing method is also implemented for the tanks with a volume of 5000 m3 or more.

Experimental investigation on the effect of open fire on the tensile properties and damage evolution behavior of granite

The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process of rock. The microstructures of the treated granites were observed by scanning electron microscope (SEM). The results showed that the fire duration and cooling treatment have a significant effect on the P-wave velocity, static nominal tensile strength, and dynamic nominal tensile strength of granite. These characteristics decrease rapidly during 0 to 10 min, and slowly decrease after 20 min. Compared to the air-cooling treatment, the water-cooling treatment has greater damage to the heated granite. To better understand the results, the rapid heating process of open fire heating was simulated using Abaqus software. The results reveal that there is a thinner compressive stress zone at the bottom of the specimen, and there is a large zone in the middle of the sample with higher tensile stress. The crack extension would be expanded due to high tensile stress, leading to the reduction of the tensile strength of the rock. This paper aims to better predict the degree of damage of rock materials after actual fire, as well as preliminarily explore the effect of the fire exposure duration and fire extinguishing method on the tensile properties of rock.

Suppression behavior of water mist containing compound additives on lithium-ion batteries fire

In this work, a new type of compound additive and water mist compatible fire extinguishing method was designed, and the effects of its suppression on a 18650 LiMn2O4/Li(Ni0.5Co0.2Mn0.3)O2 lithium-ion battery fire was investigated. To do so, a self-designed experimental platform was used to study the fire extinguishing capabilities and influence of the composite additives containing water mist on a lithium-ion battery fire. Several cell parameters were measured to evaluate the suppression effect of the fire extinguishing method, such as extinguishing time, maximum temperature, and heat release rate. The results show that both physical and chemical additives can play significant physicochemical roles in extinguishing fires and are more effective than pure water mist. The physical additives enhance the heat absorption and cooling as well as radiation heat barrier and oxygen asphyxiation mechanisms by reducing the surface tension and droplet size in the fog field. Furthermore, the chemical additives enhance the fire extinguishing efficiency by decomposing the active gases CO2 and H2O in the fire field and capturing the free radicals of the flame in the battery combustion reaction.

Bezbednost vatrogasaca-spasilaca tokom treninga u flešover kontejneru - numerička studija

Extinguishing of fire is a responsible and risky job that requires knowledge, skill and mental stability from the firefighter. These facts especially refer to the localization and extinguishing of enclosure fires where the occurrence of flaming attacks, such as flashover and backdraft are possible. In such conditions, lack of experience of firefighters often leads to fatal injuries. In order to reduce the injuries of firefighters during firefighting interventions, their training in flashover containers has recently begun. Practical training provides the necessary experience that is applied in real fire extinguishing interventions which implies that firefighters are exposed to high fire temperatures during training. Because of this, the paper focuses on modeling and simulation of flashover appearance in a container for firefighters' training, performed by using numerical fluid dynamics method. Using the Fire Dynamics Simulator software package, seven fire scenarios under different ventilation conditions and fire extinguishing methods were analyzed, with the aim of examining container temperatures that affect the safety of firefighters during the training. The obtained results indicate that the most acceptable scenario for firefighter training means that the container door is open for the entire duration of the training and, at the same time, it neccessary to periodically extinguish fire with a water jet, along with occasionally opening of the roof vent of the container.

Пожарная опасность энергетических установок газокомпрессорных станций

Introduction. The article analyzes the composition of power plants of gas compressor stations. A structural and logical model of the development of fires at power plants of gas compressor stations is compiled based on the analysis of real fires. The most dangerous scenario of fire development has been determined. On the basis of the branched-chain combustion theory, the necessary characteristics of the fire extinguishing composition are established and a technical scheme for implementing the fire extinguishing method is proposed. The purpose of the study is to creation of conditions for effective fire extinguishing of power installations of gas compressor stations. Research methods. To get the results used general scientific and special methods of scientific knowledge-analysis, synthesis, the theory of the branched-chain combustion process, the theory of thermal combustion. The results of the study. The most dangerous scenario of fire development of power installations of gas compressor stations is established. The effective characteristics of the extinguishing agent for fire extinguishing are determined on the basis of the branched-chain combustion theory. The technical implementation of this method of fire extinguishing is proposed. Conclusion. The compiled structural and logical model of the development of fires at power plants of gas compressor stations can be used by fire and rescue units when conducting operational and tactical measures. The technical implementation of the proposed method of fire extinguishing will increase the efficiency of volumetric fire extinguishing both at power plants of gas compressor stations and when extinguishing fires of thermodynamically stable liquids. Keywords: energy facilities, branched-chain process, gas compressor stations, closed spaces, volumetric fire fighting, chemical inhibition. Acknowledgments: the research is supported by the Innovation Assistance Fund under the agreement no. 15204GU / 2020 dated 05.06.2020.

Role of Active Fire Protection Systems in Ensuring an Acceptable Level of Safety of Rolling Stock

The article presents issues related to active fire safety systems used in rolling stock based on water extinguishing. The approach to active methods of fire protection and extinguishing is described in detail. The article presents the current standards, regulations and requirements regulating the use of active fire protection systems for railway vehicles in the European Union. An analysis of the elements influencing the efficiency, practicality and cost effectiveness of the extinguishing systems with the expected effectiveness of operation was carried out. The directions of development undertaken in order to develop tools for assessing the size of the threat and its prevention are presented. Keywords: fire safety, rolling stock, requirements, active fire protection systems

ASSESSMENT OF FIREFIGHTING EFFICIENCY OF VEGETATION FIRES IN CURITIBA-PARANÁ

Vegetation fires, when not controlled, cause economic disruption, temporary loss of vegetation, and damage to soil, fauna and health. To improve the process of fire prevention and firefighting, it is necessary to evaluate the performance of the involved agents. The objective of this study was to evaluate the firefighting efficiency of vegetation fires in the municipality of Curitiba, Paraná, from 2011 to 2015, using records from the Fire Department of the Military Police of Paraná. Once the consistency of the fire records was verified, they were classified and information was gathered regarding the extent of burnt area, time of first attack, combat time, main fire-extinguishing methods used, and amount of water used. The results indicate that 88% of the records registered a burnt area inferior or equal to four hectares. In addition, the mean burnt area was of 2,399.21 m², the mean attack time was of 14.1 minutes, and the mean combat time was of 29.9 minutes, all lower than the ones presented by studies from different locations. As for the fire-extinguishing methods, it was verified that smothering equipment and water were used in 66.4 and 60.6% of the records, respectively. The mean amount of water used was of 1,186.56 liters per fire, indicating a minimum volume necessary for water storage containers for firefighting in the study area. Based on the results, we concluded that the firefighting of vegetation fires in Curitiba is efficient.

A research into the potential application of unmanned aerial vehicles in the fire extinguishing of high-rise buildings and structures

Introduction. Fires in high-rise buildings and structures constitute a grave danger both to the people inside, valuables, and the building structure. More often than not, fires develop on the external surface of construction facilities that are in operation or inside those facilities that are under construction, and they give rise to the problem of using standard fire extinguishing solutions and require the employment of mobile machinery by fast response units of the fire-fighting service who apply fire extinguishing agents from the outside of a building. The purpose of this article is to substantiate the in expediency of, or, on the contrary, the need to make the proposed amendments to Federal Law No. 123-FZ of July 22, 2008 “Technical Regulation of Fire Safety Requirements”.The scope of the problem. The analysis of the effectiveness of various methods of application of fire extinguishing agents used to extinguish outdoor fires in high-rise buildings has shown the insufficiently high efficiency of ground-mounted machinery, which preconditions the need to make an enquiry into the possibility of using aircraft to extinguish high-rise buildings and structures. Given the need to ensure effective fire extinguishing, meet safety and economic feasibility requirements, an autonomous unmanned aerial vehicle (AURA) was selected as the delivery vehicle. Systems using various fire extinguishing agents and methods of their application were used for fire extinguishing purposes, including a pulsed water application system, capsules containing the fire extinguishing composition, high-pressure water mist and compressed air foam. Their applicability at the height of 300 meters has determined their choice.Research results. The testing task was to confirm the possibility of application of fire extinguishing agents to the fire seat in the course of the flight of an unmanned aerial vehicle, to identify the effectiveness of fire extinguishing agents and to assess the stability of extinguishing agents applied to the fire seat. To ensure safety, testing was carried out at the height not exceeding 10 m, and the results confirmed the possibility of using the above substances to extinguish fires.Conclusions. The research has confirmed the possibility of using unmanned aerial vehicles and various methods of fire extinguishing by means of the horizontal application of extinguishing agents inside high-rise buildings and structures, if extinguishing agents are applied from outside of a construction facility.

Introduction of a flame suppression pattern into integrated and zone models used to analyze the dynamics of hazardous factors of indoor fires

Introduction. Fire risk calculation is performed to substantiate the compliance of space planning solutions of buildings and structures with fire safety requirements. The calculation of time needed for hazardous factors of fire to block evacuation routes is performed with account for unlimited fire propagation. The only system, whose operation is taken into account if the fire risk value is exceeded, is the smoke ventilation system. The operation of other fire safety systems is disregarded due to the unavailability of reliable engineering methods of analysis of their influence on fire escalation. The problem of development of modified mathematical models, used to analyze the fire escalation pattern, with account to be taken of the process of fire extinguishing and its influence on fire propagation, is relevant. The purpose of this research is to develop common principles that allow to take account of the pattern of fire suppression in solid materials and combustible liquids by fire extinguishing substances having various origins and degrees of dispersion, if the fire extinguishing substances are added to integrated and zone models of development of hazardous factors of fire escalation.Calculation methodology. The calculations are based on the equation compiled in furtherance of principles of conservation of mass and energy in the flame zone above the surface of the combustible material.Research results. The co-authors suggest general principles for the introduction of a flame suppression pattern into integrated and zone models used to analyze the evolution of hazardous factors of indoor fires. The coauthors present the main provisions and parameters needed to modify integrated and zone models in case of different methods of fire extinguishing. The co-authors have analyzed hazardous factors of fire with account for the flame suppression pattern.Conclusions. The co-authors applied the research findings to develop the modified integrated and zone models that allow to analyze the dynamics of hazardous factors of fire with account for the extinguishing of solid materials and combustible fluids by fire extinguishing substances having various origins and degrees of dispersion.

Methods Used to Extinguish Fires in Electric Vehicles

Aim: The aim of the article is to present the current state of knowledge regarding the possibility of suppressing or effectively extinguishing fires of electric vehicle. Due to the growing popularity of means of transport powered by electric batteries, the problem of emerging fires and their effects is becoming recognizable. Due to the possible violent process of combustion of lithium-ion batteries (hereinafter referred to as Li-Ion batteries), a fire in a vehicle may lead to a wide range of property damage. For at least a decade, intensive efforts have been made to develop appropriate methods to allow firefighters to deal with the problem of fires of electric vehicles. These activities were directed, among others, at new fire extinguishing/suppression techniques, innovative extinguishing agents and methods of their application. Introduction: Taking into account the current global trends in changing the method of powering vehicles from fossil fuels into electricity, the occurrence of such events should be expected to intensify. The authors systematize the issue by analysing the literature on fires, Li-Ion batteries being a critical ele- ment that may initiate a fire. The adopted and practiced methods of extinguishing/suppressing a fire as well as the used extinguishing agents were also analysed. The publication may be an element helpful in selecting the most optimal fire extinguishing method of the electric energy storage unit in a vehicle. Methodology: The review of the current state of knowledge was made based on publications on the fire characteristics of Li-Ion batteries, as well as works and research projects in the field of extinguishing methods and the effectiveness of various extinguishing agents. In addition, the procedures used by the emergency services and selected real events were analysed. Conclusions: Fires of Li-Ion batteries are a relatively new and growing phenomenon. Fires in fully or partially electric vehicles are much more difficult to fully extinguish compared to fires in vehicles with internal combustion engines. So far, no effective method has been developed that would allow a fire to be extinguished in a short time. Activities in this area focus on minimizing the effects. There is still a need to look for new technical and tactical solutions in order to optimize the procedures leading to more effective activities of the services in this type of incidents. Keywords: lithium-ion battery, Li-Ion, fire, extinguishing, suppression Type of article: review article

Non-invasive attempts to extinguish flames with the use of high-power acoustic extinguisher

AbstractThis paper presents an innovative method of extinguishing of flames using a high-power acoustic extinguisher. This method allows for effective and non-invasive extinguishing of the flames. Experimental results showing the effectiveness of the fire extinguisher for different distances from the flame source and different frequencies of the acoustic wave are discussed. The paper ends with the description of the advantages, disadvantages, and limitations of the proposed fire extinguishing method.

Control strategy for large‐scale fires near power transmission lines and its application

To prevent fires causing the power transmission lines trip, a control strategy including the methods of fire forecasting, fire monitoring and fire extinguishing for large-scale fires under power transmission lines is proposed. A water mist fire extinguishing method for transmission lines with high-voltage was presented to ensure the fire extinguishers safe. Compared with conventional measures of fire risk evaluation and fire detection, the proposed control strategy can proactively control the fires to ensure the transmission lines run continuously, rather than passively stop running to avoid the fire. The timeliness of fires rescue for power grid is analysed statistically, and the control strategy for fires near transmission lines is presented and discussed. The proposed strategy had been widely used in Hunan province power grid of State Grid in China. After the applications, the average fire tripping number of transmission lines with the voltage levels of 220 kV and above each year was reduced by 64.6% during the period of 2015 to 2019 compared to previous five years, and there was no transmission line trip due to fire during the Qing-ming high-fire periods from 2015 to 2020, which proved the effectiveness of the proposed method.

Various electrical fires and firefighting methods

Introduction. Fires of voltage-carrying electrical units are most dangerous and difficult to put out. Personnel of fire emergency response units are at high risk of electric shock when extinguishing such fires. Electrical units have recently obtained a new are of application, that is, electric cars. Electric car design entails the use of high-capacity batteries and high voltage electrical equipment, which pose a higher fire hazard. The objective of this article is to analyze potential assets to be protected and assess existing electrical fire extinguishing methods to substantiate principal areas of research into design of safe fire extinguishing systems designated for electrical units installed on motor vehicles.Main (Analytical) part. The fire extinguishing of the items, that have electrical units to be extinguished without any electricity outage, must be performed by the fire departments that have appropriately trained and equipped personnel. However, in the event of an electric car fire, it is impossible to forecast which fire department will be nearby and how well it will be equipped. The design features of electric vehicles show that potential sources of the fire hazard include lithium batteries and electrical circuit elements. These factors explain the need to consider the problem of extinguishing self-contained electrical fires inside motor vehicles from the standpoint of electrical safety. It is suggested to identify the fire extinguishing method in furtherance of the analysis of a set of principal fire extinguishing methods with regard for the design of efficient firefighting appliances that ensure safe extinguishing of electric car fires.Conclusions. It is expedient to use the pulse application of a fire-extinguishing agent that prevents current leakage while extinguishing various types of electrical appliances, including those installed on motor vehicles. The effects of exothermic reactions, involving lithium-containing elements, were not analyzed when solving this problem. This research will serve as the basis for conceptual technological solutions designated for fire emergency response units responsible for extinguishing electric car fires.

Experimental study on the synergistic effect of gas extinguishing agents and water mist on suppressing lithium-ion battery fires

Abstract Currently, effective suppression methods are still required to deal with lithium-ion battery (LIB) fires. In this paper, a novel synergistic fire extinguishing method of gas extinguishing agent (C6F12O, CO2 and HFC-227ea) and water mist is designed to evaluate the effect of their combination. A 243 Ah large-scale LIB with LiFePO4 as cathode is used in this work. Several cell parameters are measured to evaluate the suppression effect of fire extinguishing method, such as extinguishing time, maximum temperature, mass loss and heat release rate. Meanwhile, the cooling effect, fire extinguishing effect and economic benefit of different fire extinguishing methods are all considered. Results show that the suppression effect of synergistic fire extinguishing method is better than that of the single agent. Single application of water mist can hardly extinguish the flame, while the combination of gas extinguishing agents and water mist can extinguish the flame finally. However, the C6F12O extinguishes the flame immediately, while CO2 has a longer extinguishing time, and HFC-227ea cannot extinguish the flame. So in these experiments, the C6F12O combined with water mist exhibits the best extinguishing and cooling effect. The CO2 combined with water mist has good economic benefit, better fire extinguishing effect and cooling effect in these experiments, which can also be considered in suppressing LiFePO4 LIB fires.