Fire Parameters Research Articles

Cross-physical field prediction method for smoke field distribution in commercial building fire based on distributed optical fiber sensor

In modern commercial building spaces, the smoke generated during indoor fires poses a substantial safety threat to individuals attempting to evacuate. This study leveraged a distributed optical fiber temperature sensing system as the technological foundation. A series of commercial building space models were constructed by employing fire dynamics simulations, and a comprehensive database of simulated fire field information was established. The study built upon this database and proposed a method to establish influence pathways from existing temperature field detection data to three fire risk assessment parameters: carbon dioxide, oxygen, and visibility. The study utilized various machine learning algorithms and focused on selecting and constructing cross-physical field prediction models that optimized the performance of fire risk assessment parameters at the fire key plane. The findings demonstrated that the Multilayer Perceptron (MLP) algorithm model yielded the most accurate fit for carbon dioxide volume fraction, with a Mean Absolute Percentage Error (MAPE) of 3.80% between the model predictions and actual values. The Artificial Neural Network (ANN) algorithm showed superior fitting effects for oxygen volume fraction and visibility, with MAPEs of 1.37% and 3.10%, respectively. Furthermore, the study validated the generalizability of these optimal models by altering spatial scales, revealing robust performance. This study utilized a single optical fiber sensor to achieve dynamic prediction across different physical fields during fire incidents, expanding the application scope of optical fiber sensors in monitoring gas and visibility fields in commercial building fires. This not only enhanced the level of fire monitoring but also effectively reduce equipment costs. It provided effective data support for planning evacuation routes for individuals and rescue arrangements for firefighters, further ensuring personnel safety.

Fire effects on pollination and plant reproduction: a quantitative review.

Fire may favour plant flowering by opening the vegetation and increasing abiotic resource availability. Increased floral display size can attract more pollinators and increase the absolute fruit and seed production immediately after the fire. However, anthropogenic increases in fire frequency may alter these responses. We aim to assess the effects of fire on pollination and reproductive success of plants at the global scale. We performed a systematic literature review and meta-analyses to examine overall fire effects as well as different fire parameters on pollination and on plant reproduction. We also explored to what extent the responses vary among pollinators, pollination vectors, plant regeneration strategies, compatibility systems, vegetation types and biomes. Most studies were conducted in fire-prone ecosystems. Overall, single fires increased pollination and plant reproduction but this effect was overridden by recurrent fires. Floral visitation rates of pollinators were enhanced immediately following a wildfire, and especially in bee-pollinated plants. Fire increased the absolute production of fruits or seeds but not the fruit or seed set. The reproductive benefits were mostly observed in wind-pollinated (graminoids), herbaceous and resprouter species. Finally, fire effects on pollination were positively correlated with fire effects on plant reproductive success. Fire has a central role in pollination and plant sexual reproduction in fire-prone ecosystems. The increase in the absolute production of fruits and seeds suggests that fire benefits on plant reproduction are likely driven by increased abiotic resources and the consequent floral display size. However, reproduction efficiency, as measured by fruit or seed set, does not increase with fire. In contrast, when assessed on the same plant simultaneously, fire effects on pollination are translated into reproduction. Increased fire frequency due to anthropogenic changes can alter the nature of the response to fire.

Uncertainty quantification of unconfined spill fire data by coupling Monte Carlo and artificial neural networks

ABSTRACT Due to the complexity of spill fire, predicting heat release rate (HRR) is a challenging aspect, therefore, identifying key contributors to uncertainty is essential to develop reliable models for fire risk assessment. We propose a framework that couples Artificial-Neural-Network (ANN) and Monte Carlo Uncertainty Quantification (UQ) to quantify the uncertainties of spill fire parameters on peak HRR variance. The ANN spill fire model, trained on experimental spill fire data, shows good agreement with measured HRR values. By coupling with Dakota for Monte Carlo uncertainty propagation, the framework identifies major contributors to peak HRR uncertainty for fixed and continuous unconfined spill fires. This is achieved by investigating two uncertainty sources: data scarcity and input parameters. UQ results indicate that the confidence intervals widen at points where data are scarcer. Sensitivity analysis shows that in the case of fixed quantity spills, the fuel amount and properties parameters contribute to 54.4% and 22.6% of peak HRR variance, respectively. For continuous spills, the discharge rate and fuel properties parameters account for 41.8% and 39.3% of peak HRR variance, respectively. This work can be utilized in developing more advanced predictive ANN models for spill fire scenarios, ultimately enhancing fire probabilistic safety analysis in nuclear power plants.

Simulation study on firing parameters optimization of parallel salvo of active acoustic homing torpedo

In the process of submarine anti-submarine warfare, single acoustic homing torpedo or parallel salvo acoustic homing torpedo to attack enemy submarine is usually used. According to the search sector of torpedo and the method of submarine avoiding torpedo maneuver, the model for submarine running out of search zone is established. Therefore, the necessity of using parallel salvo in anti-submarine warfare is verified. On this basis, the calculation model of firing parameters is established, and the simulation results show that the Optimization of firing parameters has great influence on the hit probability of parallel salvo. The research results have certain reference value for implementation.

Field detection of indoor fire threat situation based on LSTM-Kriging network

Obtaining the fire development information quickly and accurately is an important part of indoor fire emergency evacuation and rescue. However, at present, buildings only use fire sensors to monitor whether a fire is occurring, and there is a lack of means to obtain real-time threat situation information on the development of fires. An LSTM-Kriging neural network model is proposed in this paper, which can quickly generate an indoor fire threat field using the temporal data of fire sensors when an indoor fire occurs. Firstly, the Kriging algorithm was improved by replacing the Euclidean distance used in the variational function with the nearest passable distance to obtain a more accurate representation of the indoor threat distribution trend, and combined it with the Long Short-Term Memory (LSTM) network to construct the LSTM-Kriging network. Secondly, indoor fire scenarios were constructed in PyroSim, and fire parameters were simulated randomly. After data augmentation, the indoor fire threat situation dataset was generated. Finally, the optimized LSTM-Kriging model was trained and compared with Transformer, LSTM, and Recurrent Neural Network (RNN) on the indoor fire hazardous situation dataset. The experimental results show that LSTM-Kriging is the most effective model compared with several models mentioned above and the prediction of threatening situation reaches an accuracy of 97.8 %, with an average computation time of 0.19s on the GPU, which can meet the requirement of real-time fire situation monitoring. The indoor fire threat situation field detection method proposed in this paper achieves intelligent indoor fire detection and improves the building fire safety.

Research on characteristics of thermal smoke movements of twin fires in a tunnel under reduced pressure

In this study, numerical simulations were conducted to investigate the behavior of thermal smoke movement in tunnels under reduced pressure, with the aim of providing scientific guidance for controlling smoke and heat in the event of tunnel fires. The variables examined included fire spacing (0–6 m), atmospheric pressure (55–100 kPa), and overall heat release rate (6–18 MW). The analysis revealed that the temperature method, which considers relative temperature deviations along tunnel centerlines and on tunnel sidewalls, is effective in identifying the initial position of one-dimensional smoke movement (TY=0 - TY=4.9) / TY=0 ≤ 5 %. It was found that under reduced pressure, the mass of air entrained into the smoke gas per unit time decreased, resulting in a lower mass-flow rate. Specifically, at 100 kPa, the mass-flow rate was approximately 1.4 times higher than at 55 kPa for the same simulation scenario. The effect of fire spacing on the mass-flow rate was found to be weaker compared to pressure, particularly during the non-interaction stage of the fire. The air entrainment coefficient (β) displayed a negative correlation with environmental pressure and positively correlated with fire-heat release rate. In all cases, the β value for dual fire sources in a tunnel ranged from 0.0008 to 0.0022. Finally, a segmented function was developed to forecast the mass-flow rate of thermal smoke, taking into account various factors such as fire source parameters, environmental parameters, and tunnel restrictions.

Experimental study on the effect of sloping substrate on the spill fire in a well-confined ship engine room

Fuel leakage in the ship engine room tends to form the dynamically evolving spill fires instead of pool fires, which are full of danger and have been scarcely concerned. In this work, one-dimensional spill fire experiments with different fuel leakage rates and substrate slopes are tentatively conducted in a well-confined model-scale ship engine room to reveal their fire dynamics characteristics. It is found that the development of spill fires in the ship engine room is quite different from that in open space, and it, to a great extent, depends on the specific leakage rate and substrate slope. Typically, the spill fire in the ship engine room can be divided into five stages: continuous spreading, steady burning, burning shrinkage, quasi-steady burning, and decay stages, while the steady or quasi-steady stage does not always appear for all cases. In the quasi-steady burning stage, the thickness of the critical oil film is between 0.97 and 1.55 mm, smaller than that in the open space. The special fire phenomena are mainly attributed to the confined boundary condition, where the competing mechanisms of fuel control and ventilation control effects will collectively influence the development of the spill fire in the ship engine room. Characteristic parameters of spill fires in ship engine room, including flame spread rate, burning area, burning rate, and flame height, are also quantitatively analyzed.

Influence of Wooden Compartment’s Fuel Moisture Content on Time to Flashover: An Experimental and Numerical Study

Time to flashover is an important fire safety parameter. The present study investigated the effects of fuel moisture content on the time to flashover, crucial in fire safety analysis. Experiments and simulations of an ISO 9750-1 room model at 1/8 scale were performed by varying the wooden compartment boundaries’ moisture content between 5% and 16%. The results showed a linear increase in time to flashover with fuel moisture content. An empirical model to predict the time to flashover according to the moisture content was developed. The experiments showed that increasing the moisture from 6.5% to 14.4% prolonged the flashover time from 4.6 min to 8.75 min. These experimental results are consistent with computational fluid dynamics (CFD) modeling using Fire Dynamics Simulator (FDS), which also depicts a corresponding increase in the time to flashover. These findings demonstrate the critical role of fuel moisture content in fire safety analysis. The results suggest that a 1/8-scale model can be utilized for cost-effective and easily manageable education and demonstration purposes. This includes helping fire brigades and fire academy students comprehend the significance of fuel moisture content in compartment fire development. Since the FDS modeling is not restricted to a 1/8 scale, the presented results are promising regarding CFD modeling of time to flashover in full-scale compartments.

Проблема изложения требований норм в области пожарной безопасности в России

Purpose. The analysis of regulatory documents and scientific publications is presented, describing the discharge parameters of automatic fire extinguishing installations, as well as criteria for their design. The analysis is presented in chronological order of the documents' editions. In compliance with the requirements of regulatory documents in the field of fire safety, facilities under protection are provided with automatic fire extinguishing installations (AFEI). The currently valid regulatory documents do not specify the fire load, according to which groups of premises are classified and types and methods of fire extinguishing agents discharge are determined. The above mentioned makes it necessary to analyze the regulatory and scientific literature with the objective of further defining a unified methodology for designing automatic fire extinguishing installations. Methods. The authors have carried out a chronological analysis of special literature in order to identify the stages of AFEI discharge parameters development. All types of fire extinguishing installations, which are subject to the requirements of regulatory documents, have been studied. Findings. Based upon the outcomes of the study in question, it is possible to make a conclusion that at present the regulatory documents governing the requirements for automatic fire extinguishing installations lack current data on modern substances and materials, and therefore the methods described in this paper may be inaccurate and sometimes crucial when determining AFEI characteristics. Research application field. The outcomes of the given research may be used by: – scientific institutions within various structures and departments as the base for development of guideline values of fire load as well as requirements to AFEI working conditions; – educational institutions within various structures and departments in the course of teaching and learning activities; – manufacturers producing fire equipment intended to provide fire safety at the protected facilities of various purposes. Conclusions. The given problem may be solved be means of updating fire load parameters with the help of different software systems, as well as full-scale experiments. This will allow determining the actual fire load parameters and effective characteristics of automatic fire extinguishing installations for modern buildings and premises.

Оценка тактических возможностей звеньев газодымозащитной службы

Purpose. Determining tactical capabilities of a gas and smoke protection unit for operational planning documents developer is an abstract task: it is impossible to understand what smoke divers are capable of during the time of protective action of the breathing apparatus using the existing calculation methodology. Methods. To achieve the goal, analysis of open sources is used in the article as well as methods for calculating operating parameters of gas and smoke protection service, empirical data and mathematical analysis to predict smoke divers’ capabilities in a fire. Findings. An innovative method is proposed for assessing tactical capabilities of a gas and smoke protection service unit. Research application field. The results obtained can be widely used in smoke divers training, in calculating fire extinguishing parameters, as well as in the practical activities of firefighters and experts. Conclusions. Practical application of the method for calculating tactical capabilities of a gas and smoke protection service unit proposed in the article will allow at the stage of working out operational planning documents assessing the possibility of successful rescue operation for people in a fire at a specific facility. If rescuing people according to calculations becomes difficult, appropriate management decisions can be developed in a timely manner to eliminate these problems.

Норадренергічний вплив на тонічну імпульсацію нейронів ганглія трійчастого нерва

Adrenoreceptors play a key role in sympathetic influences on sensory neurons in normal and neuropathic conditions. We studied noradrenaline action on tonic firing in cultured rat trigeminal ganglion neurons. In a majority of the neurons (68%), Noradrenaline application had no marked effect on the firing properties. The rest of the cells (32%) were highly sensitive to noradrenaline action; they lost the ability to tonic firing and single action potential parameters significantly changed. It was established that NA-induced action on the firing is mainly due to the activation kinetics slowing of voltage-gated calcium channels. The data suggest a possibility of differential sympatho-sensory interaction in the trigeminal pathways.

Effect of Spruce Wood Density on Selected Fire-Technical Parameters during Thermal Loading

The paper evaluates the effect of spruce wood density on the parameters of mass loss and mass loss rate during exposure to thermal load. The intention was to determine whether the effect of density is still evident after the application of flame retardants to the test samples. Groups of samples with different densities under the same retardant treatment were compared. The differences in densities of the compared groups of samples were different for each flame retardant. Water-soluble flame retardants based on inorganic salts were used. For testing, a simple test method was used in which the samples were exposed to direct flame from a Bunsen burner. The results of the study are the findings of how wood density affects the burning process of the samples treated with flame retardants. Statistical evaluation of the experimental results shows a significant effect of wood density on the monitored parameters even when flame retardants are used. For a difference in sample densities of 244 kg·m−3, there was a density dependence of the mass loss rate, with the lower density samples having a higher mass loss rate (0.158%·s−1) over the whole experimental period compared to the higher density samples (0.077%·s−1). The ANOVA test also demonstrated the influence of density on the mass loss of the samples at the above density difference. At lower density differences (51 kg·m−3 and below), the effect of sample density on the observed parameters was no longer evident. The fire spread rate parameter was also investigated. Here, a linear correlation between the difference in sample densities and the difference in the values of the above parameter at high and low densities is observed with a reliability coefficient R2 = 0.99.

Realtime Monitoring and Analysis Based on Cloud Computing Internet of Things (CC-IoT) Technology in Detecting Forest and Land Fires in Riau Province

Forest and land fires in Riau are natural disasters that always repeat every time they enter the dry season. The solution of this research is to apply the leading technology of cloud computing internet of things (CC-IoT) to find out more quickly the existence of forest or land fires. This study uses Particle Argon (Photon) to connect to the internet and several IR Fire Detector sensors, DHT22 MQ2 and GPS Neo 6m. Particle Argon can receive input and perform processing so that it is connected using the CC-IoT concept to a web server so the users can monitor land conditions in real time. Based on the test results, it can be concluded that a fire detector using fire parameters (2000 = Normal and 2000 = Danger) , temperature (≤37 = Normal, 38 – 45 = Alert, and 46 = Danger), humidity (≤50 = Dry, 51 = Humid) , smoke (≤ 1700 = Normal, 1700 = Danger), and soil moisture can work well ( 3500 = Dry Moisture Content, 1500 to 3500 = Medium Moisture Content, and 1500 = High Moisture Content). The fire detection tool developed can detect fires in real time and also has a fire early detection function that is useful for anticipating land conditions to prevent fires. The results obtained from the test are that the sensor can read indications of fire, smoke, soil moisture with a success rate of 93% and send location data and sensor values to the website. The use of sensors has their respective roles so that if there is a problem with one of the sensors, the tool has an alternative sensor and can continue to function.

Influence of char‐forming lignin in combination with aluminium phosphinate on thermal stability and combustion properties of polyamide 11 blends

AbstractPolyamide 11 (PA) blends based on char‐forming industrial lignin and aluminum phosphinate (AlP) were prepared to improve flame retardant (FR) properties using a green and eco‐friendly approach. This study investigates the thermal degradation and combustion behavior of PA blends prepared by using AlP in combination with two different types of industrial lignins (i.e., kraft lignin (DL) and lignosulphonate lignin (LL). Thermogravimetric (TG) analysis showed that ternary blends containing LL and AlP developed higher char residue up to 10.7 wt% upon decomposition in inert atmospheres. The combination of lignin and AlP increases the thermal stability by shifting the initial decomposition temperature (T5%) and temperature at maximum decomposition (Tmax) to a higher temperature range, attributed to the stabilization of decomposition products. Furthermore, combustion behavior studied by cone calorimeter (forced combustion) and pyrolysis combustion flow calorimeter (PCFC) tests presented a significant reduction in the peak of heat release rate (PHRR) and total heat release (THR). It was found that LL and AlP‐containing blends more effectively decreased fire parameters like PHRR and THR than that of DL and AlP‐containing blends. The best interaction with reduced fire‐retardant properties was obtained when 10 wt% loading of lignin (DL/LL) and AlP was used. The reduction in heat release parameters was mainly ascribed to the condensed phase mechanism by forming an efficient protective char layer, which acts as a barrier against heat and mass transfer between the condensed and the gas phases. Raman spectroscopy analysis also confirmed the formation of the protective graphitic layer in the condensed phase.

High-purity corundum grinding balls, obtained by quasi-isostatic pressing

The influence of the composition of press powders based on alumina CT 3000 LS SG, quasi-isostatic pressing and firing parameters on the structural and mechanical characteristics of grinding balls with a diameter of 40 mm is shown. Process parameters of production of high-density corundum balls are optimized on the basis of revealed regularities. The results of complex studies of physical and mechanical properties of ceramic articles are given. The determining effect of the particle size of raw material component on the hardness, density and operational characteristics of the grinding bodies was revealed.

Influence of fire regime on the taxonomic and phylogenetic diversity of frog communities in a fire-prone Brazilian ecosystem

Fire is a natural disturbance that has shaped Earth's biodiversity for millions of years. In a fire-prone ecosystems, fire acts as an important environmental filter, selecting species presenting tolerant traits to fire events and post-fire environmental conditions. It is expected that intense fire activity selects for closely-related species, thus promoting a phylogenetic and functional clustering of communities. In view of the severe changes in natural fire regimes observed in different regions of the planet, an increasing body of research has been dedicated to exploring their impact on frogs, a particularly susceptible group in the context of wildfires. However, it is notable that most of the research focuses on the traditional dimension of diversity, the taxonomic diversity, leaving a significant gap in our understanding of how fire disturbances affect the phylogenetic diversity of these communities. Here, we tested the effects of three fire regime parameters (i.e., total burned area, time since the last fire and fire count at the landscape scale) on the taxonomic and phylogenetic diversity of frog communities in 26 sites within a fire-prone Brazilian protected area. We used Hill numbers to characterize the taxonomic (Species richness, Shannon and Simpson's diversity) and phylogenetic diversity (Phylogenetic richness, Mean phylogenetic diversity of common lineages and Mean phylogenetic diversity of dominant lineages). We found that the fire regime did not explain patterns of the taxonomic diversity. Nonetheless, there was a positive correlation between phylogenetic richness and the frequency of fire occurrences, while a slight negative correlation was observed with the percentage of burned area. In addition, moderate fire activity seems to be an important driver of phylogenetic diversity. Therefore, management practices toward a mosaic of areas with different fire histories are fundamental in this protected area. We finally emphasize that all diversity facets of anurans should be assessed and considered in management decisions to guaranteeing anuran conservation in this region.

Correlation of properties in hydrocarbons homologous series

Correlations between combustible substances properties in the homologous series of n-alkanes and n-alcohols with a length of nС=1–20 were studied in order to determine ways to increase the methods convergence for assessing fire hazard parameters. The cluster length was added to the substance modulating parameters set. It should be noted that substances properties are often predicted using a molecule coarse-grained model, which has discreteness, does not describe short molecules, and requires an individual approach. It is shown that there are substance "arithmetic" parameters that directly depend on the certain atoms number. Among them, "length" better reflects isomeric, conformal, cluster differences, which are associated with parameters anomalies of hydrocarbons. A vaporization heat linear description from nС separately for n-alkanes and n-alcohols gives R=0,999. Exponential approximation of the n-alkanes boiling point tbp and flash point tfp by nС change fractions has R=0,999. It is shown that there is a correlation between tfp and tbp, but with a systematic difference, which indicates that the cluster composition is not completely similar at these temperatures; between tfp and tmp there is a smaller correlation, but its presence indicates clusters partial similarity. A universal formula for predicting hydrocarbons vaporization heats of 10 homologous series has been created, which has R=0,996. The description change hydrocarbons pulsations of in tmp was carried out on the cluster schemes alternation basis in homologous series, as well as taking into account their length and molar mass, which gives R=0,9997. According to similar principles, a formula for the hydrocarbons solubility in the water has been developed, which has the satisfactory accuracy. The study showed that the cluster length is a determining factor by which substance properties are modulated.

Simulation study on fire and evacuation of super high-rise commercial building

The construction of high-rise and multi-functional commercial buildings has emerged as a global trend, but it also introduces significant fire hazards. Consequently, there is a pressing need to examine the fire development trends in super high-rise commercial buildings and establish logical evacuation strategies. This study utilizes the Pyrosim program to simulate a typical fire scenario at the Yangtze River International Conference Center, allowing for the acquisition of essential fire parameters and available evacuation time. Subsequently, based on the complex functional zones and personnel distribution within the building, appropriate evacuation plans are devised and simulated using the Pathfinder software. The results reveal that by effectively utilizing stairs, elevators, and refuge floors in accordance with personnel distribution, evacuation efficiency can be substantially enhanced. Furthermore, the required evacuation time during nighttime fires is merely 36.6%–55.3% compared to unorganized evacuation. The findings of this study offer valuable theoretical guidance for the evacuation of super high-rise commercial buildings, holding immense significance in minimizing fire-related casualties within such structures.

Assessment of clay raw materials of western Kazakhstan

The article presents the results of the estimated assessment of the clay raw materials of the West Kazakhstan Pogodaevsky and Taskalinsky fields. The calculation was made by the chemical composition of clays, focusing on the formation of low-melting triple aluminosilicate eutectics. Based on the calculated data, the melt formation dynamics curves were built, from which the possible sintering degree, sintering intervals and the recommended firing temperature were determined. A forecast was made for a change in the properties of clay raw materials with the introduction of 2% alkaline oxides. The optimal directions of use of these clays and firing parameters are determined.

Study into the Fire and Explosion Characteristics of Polymer Powders Used in Engineering Production Technologies

Polymers and their processing by engineering production technologies (injection, molding or additive manufacturing) are increasingly being used. Polymers used in engineering production technologies are constantly being developed and their properties are being improved. Granulometry, X-ray, FTIR and TGA were used to characterize polymer samples. Determination of the fire parameters of powder samples of polyamide (PA) 12, polypropylene, and ultra-high molecular weight (UHMW) polyethylene is the subject of the current article. An explosive atmosphere can be created by the powder form of these polymer materials, and introduction of preventive safeguards to ensure safety is required for their use. Although the fire parameters of these basic types of polymers are available in databases (e.g., GESTIS-DustEx), our results showed that one of the samples used (polypropylene) was not flammable and thus is safe for use in terms of explosiveness. Two samples were flammable and explosive. The lower explosive limit was 30 g·m−3 (PA12) and 60 g·m−3 (UHMW polyethylene). The maximum explosion pressure of the samples was 6.47 (UHMW polyethylene) and 6.76 bar (PA12). The explosion constant, Kst, of the samples was 116.6 bar·m·s−1 (PA12) and 97.1 bar·m·s−1 (UHMW polyethylene). Therefore, when using polymers in production technologies, it is necessary to know their fire parameters, and to design effective explosion prevention (e.g., ventilation, explosive-proof material, etc.) measures for flammable and explosive polymers.