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The paper presents a method of determining the dynamic parameters of multiple-rocket-launcher system mounted on the wheeled vehicle based on Newton's law of motion. The dynamic simulation was conducted and then the results were compared with the corre-sponding experimental data to verify the reliability of the model. The model was ap-plied in calculation and tested out on multiple-rocket-launcher system B?-21 (of Rus-sia). The theoretical model calculation results are relatively consistent with the meas-ured experimental data. The dependence of the launcher oscillation on the rate of fire was investigated, which determined the optimal rate of fire for each launcher. These results are used to evaluate the firing stability of the launcher when firing individual shots and firing bursts. This is an important theoretical basis which can be a reference for designers in the design process of improvement, manufacture, exploitation and use of a launcher mounted on the wheeled vehicle.

Результати аналізу локальних війн та збройних конфліктів сучасності свідчать про стійку тенденцію, в арміях провідних країн світу, до досягнення успіху у веденні воєнних дій за рахунок збільшення дольової частки участі далекобійного озброєння у вогневому ураженні противника у воєнних діях. У таких діях загальновійськові формування виконують функцію завершення розгрому противника. Зазначене у свою чергу призвело до модернізації існуючого та розроблення нового далекобійного озброєння у частині збільшення дальності стрільби та скорострільності, яке складає основу розвідувально-ударних бойових платформ загальновійськових об’єднань військ (сил). У країнах, які обмежені у своїх можливостях щодо швидкого розвитку далекобійного озброєння шляхом збільшення обсягу вогневих завдань підрозділів, які спроможні здійснювати дальнє вогневе ураження противника є обґрунтування відповідних науково-організаційних рішень, реалізація яких дасть змогу досягти потрібного ефекту від бойового застосування таких підрозділів. У статті за залежністю імовірності досягнення вогневої переваги над противником від ступеня реалізації вогневих можливостей, залучених до вогневого ураження противника, вогневих засобів обґрунтовано шляхи підвищення ступеня реалізації вогневих можливостей підрозділів, озброєних далекобійними засобами ураження. За результатами проведеного дослідження набула подальшого розвитку сукупність показників ефективності бойового застосування підрозділів, озброєних далекобійними засобами ураження. Запропоновані показники ефективності на відміну від існуючих дають змогу встановити залежність імовірності досягнення вогневої переваги над противником від ефективності бойового застосування зазначених підрозділів та обґрунтувати можливі шляхи підвищення ефективності їх застосування.

The occurrence rate of fire events involved with cables is high and a fire hazard analysis is needed. A cable tray may be commonly placed on a wall. The fire hazards of multiple cable trays are affected by the supporting wall to give a higher maximum heat release rate. Taking the wall constraint effect on cable burning into account, a new model for the fire heat release rate of a cable tray fire against a sidewall is developed based on small scale (cone calorimeter) measurements. The newly developed model introduces a constant m to reflect the acceleration in cable burning due to the sidewall. With a properly chosen value of m, the results obtained using the newly developed model agree well with the experimental data. The error in the peak fire heat release rate value is considerably smaller than those of other models. This work improves the understanding of the fire risk of a cable tray with a sidewall.

This paper is a re-examination to quantify the flame tilt angle of fires induced by stack effect from a heat and mass transfer perspective. In previous studies, the critical transition and length of the deflection flame were formulated. In the current study, with different kinds of fuels, the flame tilt angles under different strength of stack effect are compared. Results show that under stack effect, the flame tilt angles are quite close at the quasi-steady state within a narrow range regardless of the heat release rate of fire and the position of the open window in a stairwell, which indicates that the inertial force of air flow induced by the stack effect equilibrates dynamically with the thermal buoyancy induced by fire plume. However, the velocity of air flow drawn into the fire compartment is directly related to the strength of stack effect, which is mainly influenced by the heat release rate of fire. A new correlation for the flame tilt angle under the influence of stack effect is developed by taking the dynamic equilibrium into account. The tangent value of the flame tilt angle is linearly proportional to the 4/15 power of the heat release rate of fire. Additionally, a correlation to predict the heat release rate with the titled flame length and flame tilt angle is formulated.

The stability of combustion in the process of fire flooding requires not only a reasonable gas injection rate but also a matching exhaust rate. A reasonable injection-production balance system is very important. Based on the material balance of injection-production, the expression of injection-production ratio suitable for normal fire flooding production is established. The air injection rate of fire flooding combustion and oxygen consumption of formation pressurization is analyzed by this formula to calculate the gas production and liquid production in combustion. The reasonable injection and production parameters for the oilfield are calculated by using the oilfield parameters. It can be seen that the calculated value of injection-production ratio is consistent with the actual value, which shows that the injection-production ratio is reasonable and can guide the adjustment of production parameters in the oilfield.

The results of the research published in the article will be useful for logistic support specialists who are involved in the creation (modernization) of the samples of weapons and military equipment. A methodical approach to substantiating the firepower requirements of a promising anti-aircraft missile system (system) is presented, which provides for the assessment of the components of firepower – search capabilities, firepower and fire resource, taking into account the intensity of the air attack, range and conditions of use of the complex (systems) for each type of goal. A list of indicators of firepower is given, namely, the average time of detection and recognition, the intensity of reconnaissance of targets, the density of the flow of missile launches (rate of fire), the preparation time of the first launch, the probability of hitting a target, and the average consumption of missiles per target. It is shown that the firepower indicators of a promising anti-aircraft missile system (system) at a given level of protection should be determined provided that it is necessary to defeat a selected group of air targets with a probability of not lower than a given level. The requirements for the firepower of a promising anti-aircraft missile system (system) can be substantiated using a complex of mathematical models that provide the opportunity to study scenarios of conflict-information interaction of a promising anti-aircraft missile system (system) and air targets in the form of a simulation machine experiment. It is shown that, based on the simulation results, the indicators of search capabilities, fire performance and fire resource of a promising anti-aircraft missile complex (system), as well as the mathematical expectation of the number of people hit by the whole when the ammunition load of anti-aircraft guided missiles installed on launchers are used, should be determined.

In this study, a laboratory burning experiment was conducted to examine the combustion characteristics of Pinus densiflora surface fuel by different slope conditions such as 0°, 10°, 20°, 30° We observed the changes in forest fire behavior after fuel-bed ignition. According to the results of this study, the rate of fire spread increased as the slope angle increased; it was 14 times faster at slope angle of 30° than at 0° The fire intensity also increased as the slope angle increased, ranging from 246.73 kW/m to 2,602.96 kW/m. The flame height and tilt decreased but the length of flame increased, when the slope angle increased. The total combustion rate also decreased as the slope angle increased. Since the moisture content of canopy fuel was measured higher with the increase of the crown base height under the same slope conditions, the risk of forest fire ignition was found to be low. The findings can be used as a basic data for understanding of fire behavior by slope condition.

Fuel moisture content is one of the important factors that determine ignition probability and fire behaviour in forest ecosystems. In this study, ignition and fire spread moisture content thresholds of 40 dead fuel were performed in laboratory experiments, with a focus on the source of ignition and wind speed. Variability in fuel moisture content at time of ignition and during fire spread was observed for different fuels. Matches were more efficient to result in ignition and spread fire with high values of fuel moisture content compared to the use of cigarette butts. Some fuels did not ignite at 15% moisture content, whereas others ignited at 40% moisture content and fire spread at 38% moisture content in the case of matches, or ignited at 27% moisture content and spread fire at 25% moisture content using cigarette butts. A two-way ANOVA showed that both the source of ignition and the wind speed affected ignition and fire spread threshold significantly, but there was no interaction between these factors. The relationship between ignition and fire spread was strong, with R2 = 98% for cigarette butts, and 92% for matches. Further information is needed, especially on the density of fuels, fuel proportion (case of mixed fuels), fuel age, and fuel combustibility.

In this paper, measurement and analysis of rate of fire (ROF) and blast pressure are presented. Data acquisition and analysis software has been developed at Proof and Experimental Establishment (PXE) and same has been applied for ROF and Blast pressure measurement. The software is coded in C++. In case of ROF measurement algorithm, a moving average filter has been applied to reduce noise then peaks are detected. Thresholding and blanking period have also been applied to discard echo. In blast measurement algorithm, a moving average filter is applied for noise removal. This data is fitted to Friedlander equation. In the present case, the requirement is to measure, high cyclic rate of fire of the order of 4000–5000 rounds per minute, using a high speed and accurate data acquisition system. Blast measurement is another important aspect for performance evaluation of armaments. Blast is the phenomenon in which sudden increase in air pressure is followed by sudden decrease in pressure which produces strong current of air which may lead to severe traumatic injuries to the soldiers. As the pressure fluctuates for a few milliseconds only, thus fast and sturdy measurement setup is needed. The proposed acoustic signal processing setup efficiently meets the requirements.

Reinforced concrete structures exposed to fire retain significant residual capacity due to better fire resistance properties of concrete, and future re-use of the structure is generally possible. Nonetheless, fire induced degradation can result in a permanent loss of strength and serviceability. An accurate evaluation of residual capacity is necessary for taking informed decisions on future use and need for repairs in fire damaged concrete structures. This paper proposes a novel three-stage experimental approach for evaluating residual capacity of fire damaged concrete members. The approach comprises of evaluating response in three sequential stages, namely, during pre-fire exposure condition; during fire exposure comprising of heating and cooling phases of fire, followed by complete cool down of the member to ambient temperature; and then finally during post-fire exposure condition. This approach is applied to evaluate residual capacity of four concrete beams subject to different fire scenarios and load levels. Results indicate that fire damaged concrete beams retain significant residual capacity even after exposure to heating duration lasting beyond their prescriptive fire rating. Furthermore, decay (cooling) rate of fire exposure impacts extent of post-fire residual capacity retained in reinforced concrete beams. Also, increasing load level present prior to, and during fire exposure (including extended cool down) lead to a greater reduction in stiffness than residual capacity of fire damaged concrete beams. Finally, relatively large post-fire deflections occur in fire damaged concrete beams which adversely impact their serviceability limit state. The proposed approach can form the basis to conduct standardized tests for determining residual capacity of fire damaged concrete members.

The rate of fire spread is of paramount interest in order to prevent and control wildland fires. It has been extensively studied under laboratory conditions, but little research has been made regarding the differences between artificially constructed and natural litter. By using a specially designed sampling method, in this study differences in the rate of spread between natural and constructed pine needle litter samples are assessed using a combustion tunnel with controlled wind speed. A total of 68 experiments were conducted with four levels of wind speed and six levels of permeability (five for constructed samples and one for the natural sample). It was found that permeability has a strong influence on the rate of spread when wind speeds are high (2.1–3.6 $${\hbox {m}} \cdot {\hbox {s}}^{-1}$$ ). It was also found that while wind speed and permeability have a strong influence on the rate of spread, their combined effect is not significant. Thus, both variables may be treated independently from one another. Lastly, it was found that constructed samples with permeability of $$1 \times 10^{-7}$$ m $$^2$$ behave similarly to natural samples in terms of the rate of spread. This suggests that it is possible to use constructed samples in the laboratory by matching their permeability, and, thus, obtain realistic values for the rate of fire spread. This could be of use for medium and large scale laboratory tests, where it is not possible to use undisturbed litter samples.

Automatic system, whose kinematic characteristics have the direct bearing on the stability of the whole system, is the key constituent element of automatic weapon. It has a complex construction and works with high precision requirements. In the article, the authors mentioned the operation of the breech system with blow-back breech under the effect of the firing force. Calculation results are applied to the AGS-17 grenade launcher produced by the (former) Soviet Union and based on the manufacturer’s parameters as well as the test measurement results to evaluate the validity of the mathematical model. Besides, the article has investigated the effect of some structural parameters on the operation of automatic system. The results of the article are an important theoretical basis for determining the rate of fire, the forces acting on the gun, on the carriage, as well as repairing, replacing, and designing a new breech system with blow-back breech of automatic weapons.

The paper first reviews the mode of generation of fire whirls, their properties, and operational regimes, under well-controlled experimental conditions. The situation is different with wildfires. These are uncontrolled and less well understood. A modified analytical approach is described for these conditions. This is based on global energy levels, per unit ground area, for different fuels, and their associated rates of fire spread, under different conditions. These enable regimes of possible fire whirl generation in wildfires to be defined. The associated accuracy is not that of a laboratory flame, but it is probably practically sufficient. Only in two instances were atmospheric fires experimentally controlled. In the remainder, the rate of fire spread was a more meaningful parameter than a burning velocity, and the critical lateral velocity was seldom known accurately. Nevertheless, it was possible to relate it to the heat release rate, with both in dimensionless form.

Recoil system parameters plays a vital role for performance assessment of any artillery weapon or firearms in context of accuracy, settling time, weapon life and rate of fire. Conventional contact and non-contact measurement techniques for recoil system parameters are having limitations like non-availability of installation space, non-sustainability in such a harsh environment and vibration noise in case of optical methods. This article presents the non-contact methodology for evaluation of recoil system parameters by time resolved optical tracking of recoil dynamics. Methodology also neutralizes the vibration error or error due to movement of camera by adopting the relative tracking instead of absolute tracking.

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An extended multi-grid model is proposed to study fire evacuation in a two-exit room. The exit selection based on random utility theory, as well as the pedestrian movement in fire, is investigated. The effects of different occupant types, the utility threshold, heat release rate of fire, burning materials and pre-movement time on evacuation are discussed. The results show that active occupants are beneficial for evacuation because of their guidance to the herding pedestrians, whereas, the existence of conservative is not always good for evacuation; a proper frequency of changing target exit can relieve congestion and optimize evacuation process; evacuation time is not monotonically increasing with the increment of heat release rate due to acceleration when pedestrians feel the incentive of high temperature within limit; the effect of burning material on evacuation is related to its thermal physical properties; the pre-movement time aggravates the difficulty of evacuation due to the bad visibility and high CO concentration in fire situation. The study may be useful to predict exit selection and pedestrian movement process, and then give suggestions to guide pedestrian evacuation under fire emergency.

This paper improves the existing frameworks on simulating fire following earthquake (FFE) by explicitly modeling the suppression process and the fire department response. The paper focuses on the impacts of FFE on urban areas and quantifies induced economic losses based on resources and efficiency of the fire department during post-earthquake fires. Layers of infrastructure systems, including transportation, water, and electric networks, and the building inventory are modeled and the earthquake damage to the community is characterized. The behavior of fire spread inside and between buildings is simulated based on major fire spread mechanisms. In parallel, the suppression activities are explicitly modeled and a decision-making algorithm for fire engine assignments to locations of ignition is implemented. The proposed methodology is applied to a case study. The performance of fire department response is characterized using the probability of exceedance of unsuccessful suppression scenarios, presented in the form of fragility functions. The expected direct economic losses are also presented as a function of earthquake intensity. The proposed framework can be used for planning and response applications, and to identify the tipping point of a community, above which the rate of fire spread exceeds that of suppression and the fires burn out of control.

Changing frequencies of extreme weather events and shifting fire seasons call for enhanced capability to forecast where and when forested landscapes switch from a nonflammable (i.e., wet fuel) state to the highly flammable (i.e., dry fuel) state required for catastrophic forest fires. Current forest fire danger indices used in Europe, North America, and Australia rate potential fire behavior by combining numerical indices of fuel moisture content, potential rate of fire spread, and fire intensity. These numerical rating systems lack the physical basis required to reliably quantify forest flammability outside the environ- ments of their development or under novel climate conditions. Here, we argue that exceedance of critical forest flammability thresholds is a prerequisite for major forest fires and therefore early warning systems should be based on a reliable prediction of fuel moisture content plus a regionally calibrated model of how forest fire activity responds to variation in fuel moisture content. We demonstrate the potential of this approach through a case study in Portugal. We use a physically based fuel moisture model with historical weather and fire records to identify critical fuel moisture thresholds for forest fire activity and then show that the catastrophic June 2017 forest fires in central Portugal erupted shortly after fuels in the region dried out to historically unprecedented levels. This research was partly financially supported by the Bushfire and Natural Hazards Cooperative Research Centre. V.R.D. was funded by the Spanish Government (RYC-2012-10970; AGL2015-69151-R). The authors thank M. de Luis, R. Serrano and G. Devine for their assistance with data access. All analyses are based on publically available data from sources listed in the references

In this study, we experimentally investigated the effect of heat release rate and aspect ratio of tunnel on the plug-holing phenomena in a reduced-scale model tunnel. In the view of physics, plug-holing phenomena was analyzed to develop the new modified Froude number considering the tunnel and shaft geometrics and the heat release rate of fire for natural ventilation system. As the results, plug-holing occurred when the new modified Froude number is below 2.75. Also, when the heat release rate increased or the aspect ratio decreased, the modified Froude number decreased. The new modified Froude number might have greater flexibility and be more accurate for various tunnel fire situations compared with the existing criteria to judge the occurrence of plug-holing.

Ventilation to the scene of afire in buildings is inevitable. The inflow of fresh air from outdoors may accelerate combustion and cause serious losses of property. However, the extent of this influence on fire remains unknown. The heat release rate (HRR) is an important factor that influences disaster intensity. In this study, the mass loss method was used to calculate the HRR of a combustible by testing the mass of the burning material mass with ventilation. We selected a full-scale room to determine the influence of ventilation. Different factors that affect HRR, such as inlet velocity, jet range, and air change rate (ACH), were considered. Preliminary results suggested that the HRR of a fire would not change significantly under different ACH conditions with indirect air supply. When the distance of the air supply was shorter than 1.5 m, a maximum difference of 1.8 times was found between indirect and direct air supply. The HRR with direct air supply is the function of air velocity and jet range. This function was used to quantify the effect of direct air supply on HRR.

Wind action on the flow behavior of the window plume along the exterior wall of a building was studied by analytical and numerical methods. Heat release rate of fire and outside wind speed were varied in the study. It was found that the window plume would flow downward under side wind. Fire might spread to the room above the window when the wind speed was low. With the wind speed increasing, the plume would be blown to downward direction, giving hazardous conditions to rooms at downstream of the wind. The tilted angle of the window plume was derived by theoretical analysis.

This paper presents discussions regarding informal settlement (also known as slums, shantytowns, favelas, etc.) fire dynamics and lessons learnt from full-scale tests on dwellings, typically referred to as “shacks” in South Africa. Smoldering and flaming fire setups are considered, and both timber and representative household contents are used as fuel sources. It is shown that due to the small size of shacks, flashover can be obtained within minutes. Maximum temperatures recorded are typically around, or in excess of, 1000 °C, depending on the fuel and structural configurations. Due to the poor construction methods used for such structures, they can collapse, or walls can open up, meaning that ventilation conditions continuously change and are difficult to accurately define. The presence of flammable wall finishes or drapes has a significant effect on the rate of fire spread and fire behavior, and such flammable finishes are often present in dwellings. Computational fluid dynamic (CFD) software [Fire Dynamics Simulator (FDS)] is utilized to analyze certain tests, which generally shows good correlation. However, due to significant variations in fuel contents, ventilation conditions, structural configurations, and wall finishes, there is a high degree of uncertainty inherent in developing models for such environments. From the work, a greater understanding of fire dynamics in low income, temporary structures (comparable with some refugee camps) can be obtained through which better solutions and interventions can be developed. Recommendations are provided for how to simulate shack fire scenarios in experimental testing more effectively.

Background Fire managers tasked with assessing the hazard and risk of wildfire in Alaska, USA, tend to have more confidence in fire behavior prediction modeling systems developed in Canada than similar systems developed in the US. In 1992, Canadian fire behavior systems were adopted for modeling fire hazard and risk in Alaska and are used by fire suppression specialists and fire planners working within the state. However, as new US-based fire behavior modeling tools are developed, Alaskan fire managers are encouraged to adopt the use of US-based systems. Few studies exist in the scientific literature that inform fire managers as to the efficacy of fire behavior modeling tools in Alaska. In this study, I provide information to aid fire managers when tasked with deciding which system for modeling fire behavior is most appropriate for their use. On the Magitchlie Creek Fire in Alaska, I systematically collected fire behavior characteristics within a black spruce (Picea mariana [Mill.] Britton, Sterns & Poggenb.) ecosystem under head fire conditions. I compared my fire behavior observations including flame length, rate of spread, and head fire intensity with fire behavior predictions from the US fire modeling system BehavePlus, and three Canadian systems: RedAPP, CanFIRE, and the Crown Fire Initiation and Spread system (CFIS). Results All four modeling systems produced reasonable rate of spread predictions although the Canadian systems provided predictions slightly closer to the observed fire behavior. The Canadian fire behavior prediction modeling systems RedAPP and CanFIRE provided more accurate predictions of head fire intensity and fire type than BehavePlus or CFIS. Conclusions The most appropriate fire behavior modeling system for use in Alaskan black spruce ecosystems depends on what type of questions are being asked. For determining the rate of fire movement across a landscape, REDapp, CanFIRE, CFIS, or BehavePlus can all be expected to provide reasonably accurate estimates of rate of spread. If fire managers are interested in using predicted flame length or energy produced for informing decisions such as which firefighting tactics will be successful, or for evaluating the ecological impacts due to burning, then the Canadian fire modeling systems outperformed BehavePlus in this case study.

Prescribed fire is an important management practice used to control woody encroachment and invasive species in grasslands. To use this practice successfully, managers must understand the seasonal windows within which prescribed fire can be applied and how fire behavior could potentially vary among these windows. To characterize prescribed fire windows within the northern Great Plains of North America, we collected data from 20 remote weather stations positioned across North Dakota and northwestern Minnesota, USA, from station inception to 2015. We performed an hourly analysis for each station to determine if air temperature (2 to 43 °C), relative humidity (25 to 80%), and wind speed (6.44 to 24.12 km h− 1) conditions were within acceptable ranges for at least six contiguous precipitation-free hours from 0800 to 1800 h. We summarized acceptable conditions over five half-season windows and then used the Rothermel fire spread equation to simulate fire behavior within these half-season windows based on average, minimum, and maximum conditions for seasonally appropriate live herbaceous to fine dead fuel ratios. While the number of acceptable prescribed fire days did not change from early spring (21 March) to early fall (6 November), the number of acceptable days for conducting spring fires decreased and the number of acceptable days for conducting late summer to early fall fires increased over the study period. The change in spring acceptability reflected an increase in the number of days with air temperatures below acceptable minimum temperature and outside of acceptable wind conditions to conduct operations. Predicted rate of fire spread was highest and most sensitive to the season of the year, fuel curing status, and site invasion status when fire spread was simulated at the upper end of acceptable wind speed and at the lower end of fuel moisture conditions. Prescribed fire planning needs to take into account the timeframe during which fire windows exist within a year, and how these conditions affect fire behavior. In the northern Great Plains, there is ample opportunity for grassland managers to use summer and fall prescribed fires, and managers should expect to get variable fire behavior results when prescribed fires are applied in more extreme conditions throughout the year.

Frequent fires cause losses of human lives and properties. These losses can be reduced by the effective coverage of fire station services. Therefore, a model to estimate the effective coverage rate (ECR) of fire station services is required. In this study, the objective of ECR was proposed to be not less than 90% in at least 90% of the time. Based on this objective and real-time travel times calculated from online maps, a model to estimate the ECR of fire station services was developed. To validate the estimation model, 2002 fire incidents and six fire stations in Loudi were selected as case studies. 168 estimation scenarios in seven consecutive days were set and 336,336 valid samples were obtained. The total effective coverage rate (TECR) of fire station services in Loudi was 36.04% and its service level was low. Results from visualizations showed that many uncovered points were concentrated in urban areas. Considering the economic constraints, four fire stations were recommended to be built in these areas. This proposed method is applicable to estimate TECRs of other cities.

Double-layer grid structures with long span are widely applied by complex buildings such as airport terminal halls, super high-way train stations, conference & exhibition halls, sport studios, warehouses and so on. As the area of the fire source located in the large volume space is rather smaller than that of floor, this kind of fire scenario is named as localized fire with non-uniform temperature distribution. In present paper, a new temperature-time curve has been firstly developed to describe the transient non-uniform temperature distribution in localized fire, which is dependent on the space size, heat release rate of fire source. Then, the mechanical behaviors of global double-layer grid structures subjected to localized fire have been investigated by using numerical method. As a part of the structure is subjected to heating strongly and the heated members are restrained by the adjacent members which are heated slightly, some chords hold the characteristic of axially restrained members. The mechanical behaviors of chords with different axial restraint stiffness due to different non-uniform temperature distribution which can be described by the new temperature-time curve have been deeply studied. The initial imperfection can strongly improve the buckling resistance for axially restrained chords. An analytic method has been developed to estimate the fire resistance of double-layer grid structures exposed to localized fire.

The experiment was conducted to demonstrate the behavior of fire propagation in wildlands using a matchsticks forest model. A model forest was designed on a flame resistant clay, on top of which matchsticks were inserted and kept vertical to the ground by keeping space between them constant with the help of aluminum grid. The data for distance travelled by fire with time were taken at wide range of slopes from downhill of ﹣25° to uphill of 45° on a model forest of packing ratios 0.08 and 0.04. The minimum rate of fire spread was observed around 15° downhill. The data collected from this experiment follow tan2θ and agree with the Rothermel’s mathematical model of fire propagation except at elevation above 35° for low packing ratio.

Due to the small width and the large train blockage ratio in subway tunnel, the smoke back-layering will be different from that in the wider road tunnel with small vehicle blockage ratio. In the train blockage region of tunnel, the velocity of longitudinal ventilated air-flow interacting with the back-flowed smoke gas is different from that in the upstream tunnel without train blockage. Then the back-flowed smoke gas might be prevented in the train blockage region with higher ventilation velocity, otherwise it would be stopped in the upstream tunnel without train blockage but with lower ventilation velocity. They were taken into consideration separately and an equivalent fire source was introduced by dividing the dimensionless heat release rate of fire source into two parts in the cases where the smoke back-layering length is longer than metro train length. A series of full-scale numerical simulations are carried out with FDS to investigate the smoke back-layering length in subway tunnel with different train lengths and longitudinal ventilation velocities. The simulation results indicate that the influence of metro train length on the smoke back-layering is great and cannot be ignored any more. A global correlation model is proposed based on the dimensionless analysis and simulation results.

Background In Ghana, fire incidents have become a regular occurrence, with thousands of lives and millions of dollars lost every year. Hardly a day passes without news of a fire outbreak in some part of Ghana, causing fear and panic among the people. This generates much discussion centering on rumors relating to politics, sabotage, misfortune, religious differences, etc. This article seeks to discuss the trend of fire incidents occurring in Ghana from 2000 to 2013 and the different ways to prevent these incidents. Methods The pattern of fire incidence in Ghana as a whole as well as in each region is discussed. The study took into consideration the causes, mechanisms, as well as preventive measures against the fire menace. Data were obtained from the head office of Ghana's national fire service. Results It was noticed that in general the rate of fire incidence increased each year. This increase was attributed to several factors: rate of population growth and industrialization, unstable electricity, urbanization, negligence, illegal electrical connection, etc. The cause of fire was categorized into domestic, industrial, vehicular, institutional, electrical, commercial, bush, and others. Among these causes, domestic fire accounted for 41% of the total number of fire incidents in the country. Conclusion Finally, this study presents several recommendations to help prevent and mitigate fire incidents in Ghana.

This paper analyses the various configuration for the emergency ventilation system consisting of an air curtain and exhaust fan to manage the dispersion of heat and toxicity inside an enclosure for different fire scenarios. Employing this ventilation system is helpful to secure an escape route or extinguishing the fire. The air curtain discharge velocity is 10, 18, and 30 m / s and its discharge angle is set to be 0 ° , 15 ° , and 30 ° . Three values of 0.5, 1, and 2 m 3 / s are considered for the exhaust flow rate. Computational Fluid Dynamics simulations have been conducted with a steady laminar flamelet model and buoyant standard k − e turbulence model to assess the performance of the air curtain and emergency exhaust system for smoke confinement. Evaluation of an optimized state of the emergency ventilation system is provided by the Taguchi method due to computational limitations in solving various cases for the ventilation system configuration. Results show that for each location and heat release rate of fire, it is possible to manage heat, CO, and CO2 dispersion with the adjustment air curtain parameters and emergency exhaust system. Finally, the optimum state of the system is reported for each scenario, and the temperature and concentration of toxic gas have been compared. Results show that for the 200 kW fire, 2 m 3 / s exhaust flow rate with air curtain discharge velocity of 18 m/s and 15 ° would be adequate. However, 500 kW fire requires 30 m/s with 30 ° discharge velocity to contain the fire inside the compartment.

A recent numerical simulation study by Moinuddin et al. (2018) determined that over a specific range of Froude numbers defined by them as ‘plume mode’, grass fuel height has a strong inverse effect on the rate of fire spread in grasslands. They then suggested that a relationship for effect of fuel height derived from their simulation results could be used to support fire management decision-making. The present analysis used fire spread measurement data from two outdoor experimental burning studies in grass fuels where an explicit control of fuel height was imposed to verify the realism of their results. It was found that a reduction in grass height, with or without removal of the cut fuel and regardless of the Froude number, led to a significant reduction in rate of fire spread, a result opposite to the simulations obtained by Moinuddin et al. (2018).

Fire accidents induced by indoor energy combustion occurred frequently and caused tremendous loss. This paper investigated the evolution laws of important fire risk parameters for quantitatively assessing the thermal hazard of room with triangular windows by reduced-scale experiments. The fire hazard was characterized by the risk parameters of hot gas temperature inside the room and facade flame height. Results show that the neutral plane position is hardly affected by total heat release rate of fire source, and it mainly depends on triangular opening height rather than base width. The ratios of neutral plane height above opening bottom to opening height are about 0.25, 0.25 and 0.61 for isosceles, right and inverted right triangular openings respectively. Based on theoretical derivation, an appropriate ventilation factor for triangular opening was defined to describe air mass inflow rate during under-ventilated condition. The hot gas temperature inside the room can be predicted based on the newly defined ventilation factor. Finally, a non-dimensional correlation was proposed to characterize facade flame height as a 0.53 power function of a normalized excess heat release rate. This work is of benefits to evaluate the fire hazard of buildings and then to provide calculation basis for building fire protection design.

The collective analysis of a relatively large number of wildfire observations documented in conifer forests, dry eucalypt forests and temperate shrublands revealed that the forward rate of fire spread is roughly 10% of the average 10-m open wind speed, provided both are expressed in the same units (e.g. km h −1 ). Knowledge of a wildfire’s forward spread rate is a prerequisite for defining adequate fire suppression strategies and to ensure timely public warnings. We wanted to investigate the possibility that a simple relationship exists that could be used as a first approximation for quickly estimating a wildfire’s spread rate simply from the open wind speed alone. We analysed data from a number of high-intensity wildfire observations (n = 118) documented in temperate shrublands, Australian dry eucalypt forests and North American conifer forests to examine the suitability and soundness of a relationship between wind speed and rate of fire spread. We also contrasted the performance of the best function against established fire spread rate models for the three fuel types. The resulting rule of thumb is that the forward rate of spread of wildfires burning in forests and shrublands in relatively dry conditions is approximately equal to 10% of the average 10-m open wind speed, where both values are expressed in the same units. The rule of thumb gives the most accurate results for dry fuel and high wind speed conditions with reduced bias and mean relative errors lower than 50%. Under these conditions, the error statistics are comparable to those obtained by the established fire spread rate models. The rule is not applicable to grasslands.

The subject of the article is an assessment of the possibility of improving the security of the personnel of units during the operation of mortars. The purpose of the article is to study the possibility of increasing the strength of mortar barrels. The task is to analyze the causes of the increased deaths of mortar fire teams during the operation of mortar barrels. Identify the main areas of work to prevent mine explosions in the mortar channel and identify ways to eliminate them by improving the methods of combat use; keep security measures during the shooting; increase the technical training of the personnel of the units; development and use of new technical solutions for the development of mortars. The work considers and suggests an analytical method for increasing the strength of mortars, based on the application of the principle of combined structures. As a result of the researches the model of definition of the resulted pressure and limiting pressurein the combined cylinders is offered. The results of calculating the limiting pressure in cylinders are given in the paper. Conclusions: the article investigates the possibility of increasing the strength of mortars. The theory of combined cylinders was proposed to increase the strength of mortars. The calculation of the internal pressure for the construction of the mortar in the form of combined cylinders is carried out. Further studies are related to the fact that the theory of combined cylinders creates prospects both in the development of high-pressure technology and in the creation of lighter and more stable structures. Предмет статті - оцінка можливості підвищення безпеки особового складу підрозділів при експлуатації мінометів. Науковою основою досліджень процесу навантаження ствола міномету при пострілі є: теорія пружності, пластичності і міцності матеріалів, теоретичні основи забезпечення живучості зброї при веденні бойових дій, теорія надійності зразків озброєння, математичне моделювання, математичне планування експериментів, методи скріплених конструкцій, суміщених циліндрів. Мета статті - дослідження можливості підвищення міцності стволів мінометів. Завдання - проаналізувати причини випадків загибелі бойових розрахунків мінометів, що почастішали, при розриві стволів під час експлуатації мінометів. Виявити основні напрями роботи по відвертанню вибухів мін в каналі ствола міномета і визначити шляхи їх усунення за рахунок удосконалення способів бойового застосування; дотримання заходів безпеки при проведенні стрільб; підвищення технічної підготовки особового складу підрозділів; розробки і використання нових технічних рішень при розробці мінометів. Результати досліджень. У роботі розглянутий і запропонований аналітичний метод підвищення міцності стволів мінометів, на основі застосування принципу поєднаних конструкцій. В результаті проведених досліджень запропонована модель визначення приведеної напруги і граничного тиску в поєднаних циліндрах. У роботі приведені результати розрахунку граничного тиску в циліндрах. Висновки: в статті досліджена можливість підвищення міцності стволів мінометів. Запропоновано для підвищення міцності стволів мінометів використати теорію поєднаних циліндрів. Проведено розрахунок величини внутрішнього тиску для конструкції міномета у вигляді поєднаних циліндрів. Подальші дослідження пов'язані з тим, що теорія поєднаних циліндрів створює перспективи як в розвитку техніки високих тисків, так і в створенні легших і міцніших конструкцій.

Aim of the study: To develop regression models for estimating the rate of surface fire spread in a thinned even-aged black pine stand ( Pinus nigra J.F. Arnold subsp. nigra var. caramanica (Loudon) Rehder). Area of the study: The study was carried out within a thinned black pine forest located in the Kastamonu Forest District, northwestern Turkey. The study area is located at 546819, 4577880 UTM. Material and methods: A total of 33 small scale surface fires were ignited under varying weather and fuel conditions. Line ignition was used during the burnings. Surface fuels consisted generally of thinned material (needle+branches). Main results: Within the stand, surface fuel loading ranged from 3.0 to 10.2 kg/m 2 . Wind speed ranged from 0.3 to 8.4 km/h. Needle moisture content ranged from 8 to 15%. The rate of fire spread ranged from 0.47 to 6.92 m/min. Relationships between the rate of fire spread and fuel and weather conditions were determined through regression analyses. Research highlights: Wind speed was the most important factor on the rate of fire spread and explained 85% of the observed variation in the surface fire rate of spread within a stand.

The method of traditional fire detection has many deficiencies. Not only being susceptible to been interference by environmental factors, but also not to find a lot of information timely and effectively from the fire inspection information. At the same time also not to record the specific details when the fire breaks out. These make it difficult for subsequent fire cause investigation. Therefore, this paper puts forward a new method for fire detection and identification by using visual attention mechanism. That is, through simulation of the human visual system, visual attention mechanism can help us from a lot of complex images to quickly find the information “been worth noting” of the image to find critical information, and to eliminate a lot of useless information. The method can significantly speed up image processing and improve the accuracy of image recognition. Several experiments have been designed to verify the effectiveness of the method by using SVM learning and training. The experimental results denote that the novel algorithms based on visual attention mechanism and been mixed linear function nuclear and radial basis function nuclear improve the accuracy and speed of recognition, significantly reduces the false negative rate of fire recognition and improves the accuracy of fire detection.

Understanding how future climate periods influence fire behaviour is important for organizing fire suppression strategy and management . The meteorological factors are the most critical parameters affecting fire behaviour in natural landscapes; hence, predicting climate change effects on fire behaviour could be an option for optimizing firefighting resource management. In this study, we assessed climate change impacts on fire behaviour parameters (rate of fire growth, rate of spread and fireline intensity) for a typical Mediterranean landscape of Greece. We applied the minimum travel time fire simulation algorithm by using the FlamMap software to characterize potential response of fire behaviour for three summer periods. The results consisted of simulated spatially explicit fire behaviour parameters of the present climate (2000) and three future summer periods of 2050, 2070 and 2100, under the A1B emissions scenario. Statistical significant differences in simulation outputs among the four examined periods were obtained by using the Tukey’s significance test. Statistical significant differences were mainly obtained for 2100 compared to the present climate due to the significant projected increase in the wind speed by the end of the century. The analysis and the conclusions of the study can be important inputs for fire suppression strategy and fire management (deployment of fire suppression resources, firefighter safety and exposure, transportation logistics) quantifying the effect that the expected future climate periods can have on fire suppression difficulty in Mediterranean landscapes.

The region model analysis is an important method for analyzing the interior fire hazard. Based on the mass conservation equation and energy conservation equation of the pre-flashover interior fire hazard development, the formulae required by computer programming are derived. VB is utilized as a tool for developing computation program with the aid of object programming idea to apply the mathematical modelling theories of the release rate of fire heat, plume and heat transfer. The relevant programming procedures and computation flow chart are presented. The program is verified through experimental data from Tianjin Fire Research Institute. Comparing with the experimental data, we can find that the program fails in effectively simulating the attenuation stage of temperatures, and the result is closer to the shape of standard temperature curve. As the computation of plumes is oversimplified, the thickness change of the smoke layer and the results obtained in the experiment vary considerably. The main advantage of the proposed computation model is that it is ease to be utilized for a variety of occasions.

The two basic strategies in the event of a fire are evacuation and “defend in place.” For the latter, fire and building codes utilize a strategy of compartmentalization. In order to create these compartments, walls and openings must be constructed of materials that will prevent or retard the passage of heat, flame, and hot gasses. Compartments are created by building a fire wall to subdivide a building. Any openings in that wall, such as doors or windows, must possess a fire resistance rating matching that of the wall. If a fire wall contains duct work that passes from one side of the wall to the other, the codes require the wall to be equipped with a fire or smoke damper. The codes also strive to limit the rate of fire spread in a building by regulating the type and quantity of materials used in the interior finish components.

Image fire detection technology can solve the problem of large space fire safety effectively. It is difficult to accurately divide the flame area because of the complex background of large space fire image, so it has a higher problem of false alarm. We propose a three-layer combination segmentation model, which use the differential technology, RGB color segmentation technology and morphological difference technology, the suspected area of the flame is obtained by excluding most of the interference. Some characteristics such as similarity measure, area change value, density, eccentricity ratio, offset distance of centroid point are extracted from suspected area of fire image. Finally, the fire identification model is established by RBF neural network, and the extracted flame characteristics is used as input to classify the fire images. A series of fire images and sample images have been experimented, the simulation results show that the algorithm can reduce the fire alarm rate effectively and improve the accuracy rate of fire alarm.

The forest-fire not only brings great loss to natural resources, but also destructs the ecosystem and reduces the soil fertility, causing some natural disasters as soil erosion and debris flow. However, due to the lack of the prognosis for forest fire spreading trend in forest fire fighting, it is difficult to formulate rational and effective fire-fighting scheme. In the event of forest fire, achieving accurate judgment to the fire behavior would greatly improve the fire-fighting efficiency, and reduce heavy losses caused by fire. Researches on forest fire spread simulation can effectively reduce the loss of disasters. The present study focused on the simulation of “29 May 2012” wildfire in windthrow area of Changbai Mountain. Basic data were retrieved from the “29 May 2012” wildfire and field survey. A self-development forest fire behavior simulated program based on Rothermel Model was used in the simulation. Kappa coefficient and Sorensen index were employed to evaluate the simulation accuracy. The results showed that: The perimeter of simulated burned area was 4.66 km, the area was 56.47 hm2 and the overlapped burned area was 33.68 hm2, and the estimated rate of fire spread was 0.259 m/s. Between the simulated fire and actual fire, the Kappa coefficient was 0.7398 and the Sorensen co-efficient was 0.7419. This proved the application of Rothermel model to conduct fire behavior simulation in windthrow meadow was feasible. It can achieve the goal of forecasting for the spread behavior in windthrow area of Changbai Mountain. Thus, our self-development program based on the Rothermel model can provide a effective forecast of fire spread, which will facilitate the fire suppression work.

Made available in DSpace on 2018-12-11T16:48:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-04-01 This paper describes the development of a logistic model to predict the probability of surface fire spread in Brazilian rainforest fuels from outdoor experimental measurements. Surface fires spread over litter composed mostly of dead leaves and twigs. There were 72 individual outdoor experiments in eighteen sites. The fire propagated in 49% of the experiments. In each experiment, the litter height, litter temperature, unburned litter mass, wet and dry litter mass, soil temperature, wet and dry soil mass, ambient wind velocity, ambient air temperature, ambient air relative humidity and duration of fire spread were measured. Using these data, the rate of fire spread, litter bulk density, litter and soil moisture content, litter load and litter residue fraction were determined. For the sake of analysis, experimental results were classified into two groups: one for which the fire propagated and the other one for which the fire self-extinguished. Analyses of a logistic regression model showed that the relevant parameters for fire propagation are litter height and litter moisture content. Concerning the probability of successful fire propagation, the model showed a true positive rate of 71% and a true negative rate of 84%. The outdoor experiments also served to gather data to improve the understanding of surface fires and to provide input data for future computer simulations. Universidade de São Paulo (USP), Av. Prof. Mello de Morais 2231 Instituto Nacional de Pesquisas Espaciais (INPE), Rodovia Presidente Dutra km 40 Universidade de Brasília (UnB), Asa Norte School of Environmental and Forest Sciences University of Washington, Mail Box 352100 U.S. Forest Service Pacific Northwest Research Station Pacific Wildland Fire Sciences Lab Universidade Estadual Paulista (UNESP), Av. Ariberto Pereira da Cunha 333 Universidade Estadual Paulista (UNESP), Av. Ariberto Pereira da Cunha 333

A field-based experimental study was conducted in 50×50m square plots to investigate the behaviour of free-spreading fires in wheat to quantify the effect of crop condition (i.e. harvested, unharvested and harvested and baled) on the propagation rate of fires and their associated flame characteristics, and to evaluate the adequacy of existing operational prediction models used in these fuel types. The dataset of 45 fires ranged from 2.4 to 10.2kmh−1 in their forward rate of fire spread and 3860 and 28000 kWm−1 in fireline intensity. Rate of fire spread and flame heights differed significantly between crop conditions, with the unharvested condition yielding the fastest spreading fires and tallest flames and the baled condition having the slowest moving fires and lowest flames. Rate of fire spread in the three crop conditions corresponded directly with the outputs from the models of Cheney et al. (1998) for grass fires: unharvested wheat → natural grass; harvested wheat (~0.3m tall stubble) → grazed or cut grass; and baled wheat (