Smoke Gases Research Articles

Determining performance characteristics of jet water-gas ejectors for an opening in a vertical fencing structure

The object of this study is jet water-gas ejectors (JWGEs) in the system for ensuring fire safety of ships. The problem that was solved: in the event of a fire, in the shortest possible time, a high temperature rises in the area of ​​the exit from the ship's emergency room and a large amount of smoke spreads throughout the ship's premises. These factors require immediate sealing of the emergency room, which limits the immediate access of emergency teams to the interior. Installation of a local air support system based on JWGE in the doorway could make it possible to shield thermal energy and localize smoke gases in the emergency room without sealing it to ensure prompt access of emergency teams. The main results that were achieved relate to the adequacy of theoretical studies on the processes of localization of flue gases in the emergency room without its sealing confirmed by the experimental method. The investigated problem was solved by optimizing processes: the intensity of smoke emission from the working characteristics of jet water-gas ejectors; the rate of change of the natural indicator of the weakening of the environment at the start of JWGE system; speed of reaching the required temperature from the time in the adjacent room. Special feature of the results was the formation of an air curtain, obtained by the selection of a part of high-temperature flue gases into the JWGE housing, their heat and mass exchange treatment and output back into the flow. This created conditions under which thermal energy shielding occurs with a fairly high efficiency of 85–88 %. And it was also established that the decrease in the intensity of gas exchange through the open hole, in which the JWGE works, occurs already at the 0.3 MPa regime in the fire pipeline. The scope and conditions of practical use of the reported results are shipbuilding and ship fire safety design

Experimental study on the flame merging and temperature profile produced by two pool fires beneath the curved ceiling

Compared to single-source fires in tunnels, double-source fires may exhibit more intricate flame merging behavior and higher flame burning rates due to their interaction, thereby escalating the risk of fire propagation within the tunnel. In this investigation, a 1:10 scale model of a horseshoe-shaped tunnel test site was deployed to conduct experiments on lateral double-source fires, scrutinizing flame merging behavior, probability prediction models, and temperature characteristics of tunnel ceiling smoke gas by varying the oil pool size and double-source spacing. Findings from the study suggest that flame merging behavior within the tunnel is contingent upon double-source spacing and heat release rate (HRR), manifesting in three distinct forms: complete merging, intermittent merging, and complete separation. Through the introduction of non-dimensional heat release rate and non-dimensional fire source spacing, a piecewise function has been devised to forecast the probability of flame merging for both fire types. Furthermore, a predictive model for the maximum temperature rise along the longitudinal centerline of a horseshoe tunnel was formulated, drawing from established theoretical frameworks.

Experimental Study on Combustion Characteristics of Solvent and Fire Behavior During a Solvent Fire at Nuclear Fuel Cycling Facility

A fire accident is one typical postulated accident in a nuclear fuel cycling facility. Safety-related data on a combustible fire are necessary to evaluate the safety of nuclear fuel cycling facilities under fire accident conditions quantitatively. Accurate and reliable data should be obtained by performing some demonstration tests. This study deals with the ignition and combustion characteristics of solvent involved at a nuclear fuel cycling facility and the fire behavior during a solvent fire. Small-scale and large-scale tests were conducted at the China Institute for Radiation Protection. The minimum ignition energy of the solvent under different temperatures was obtained. The test data were used to judge the possibility that the organic solvent ignited by a spark. Parameters such as combustion rate, smoke gas, aerosol release of solvent combustion, temperature distribution, and pressure change in the solvent fire cell were also obtained. The test results can be used as conservative estimates of the amount of aerosol release during a solvent fire. The experimental data also can be used to develop preventive and mitigation measures for solvent fire accidents. This paper puts forward information based on the experimental data and the recent international study.

Exploring Overpressure Events in Compartment Fires

For more than a century, smoke explosions have been documented in the fire research literature. Yet even with this long history, smoke explosions have received very little attention in the fire research community. The few review articles on unexplained explosions (overpressure events) have adopted the conventional names of smoke explosions, backdraft, smoke gas explosions or rapid fire progression. Anecdotal evidence from firefighters have shown a number of overpressure events that cannot be explained as a gas leak or flammable liquids ignition. In this study, experiments were conducted in a plywood lined compartment with a timber crib as a sustained fire source and the ignition source. The compartment had a single vent that was open for the entire time. After an extended period of burning, the flames detached from the crib, traveled around the compartment, and finally self-extinguished. Sometime after the flames self-extinguished, the compartment erupted in flames culminating in a large horizontal flame projecting more than 2 m from the vent opening. In this study, a consistent cycle that leads to an overpressure event has been identified. A total of 29 overpressure events were created in 13 experiments with many experiments experiencing multiple overpressure events. Gas species, compartment temperatures, vent velocities, and compartment pressure were all recorded during the experiments. Conditions in the compartment immediately prior to the overpressure event are reported. Having demonstrated that an overpressure event within a combustible compartment can be reproduced, future research is recommended to better quantify the conditions leading to an overpressure event.

System of Smart Home Based on Speech Recognition with Machine Learning

This article designs and implements a system of smart home based on speech recognition with machine learning and Android. The STM32 microcontroller is combined with actuating components to control home devices by obtaining server control commands through the network. This article designs a smart home APP based on Android and Google Voice Search, optimizes the speech recognition algorithm by using the training results from Word2Vector model to improve the recall rate of the speech recognition of command samples. This APP displays environmental data according to the scenario for users, such as the temperature, humidity, and alert of smoke gas. The test results show that the recognition recall rate of the test data of control commands from users of different ages is increased to 94.4% with high stability.

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.

Self‐ignition of forest soil samples demonstrated through hot storage tests

AbstractThe increasing threat of forest fires on a global scale is not only a matter of concern due to the potential harm they may cause to both human and animal life but also due to their significant role in exacerbating climate change. In light of these circumstances, one might inquire as to whether forest soil can self‐ignite and, if so, under what conditions and at what temperatures this phenomenon may occur. This question is being addressed in the German pilot “Fire science of wildfires and safety measures” of the EU project TREEADS, and the first results are presented below. The importance of basic research into the self‐ignition of forest soil cannot be underestimated, as it provides crucial knowledge to prevent forest fires and protect human and animal health. Furthermore, mitigating the occurrence of forest fires can also play a role in reducing greenhouse gas emissions, contributing to global efforts to combat climate change. The procedure of the hot storage test is an effective means of determining whether a material can self‐ignite. During the investigation of six soil samples, it was found that five of them were indeed capable of self‐ignition. In addition to determining whether the material ignites, the modified hot storage test also analyzed the resulting smoke gases and measured their concentration. The research question of whether regional forest soil is capable of self‐ignition can be answered with yes based on these initial tests. Further experiments are needed to determine if self‐ignition causes forest fires.

Enhancing fire safety in underground mines: Experimental and large eddy simulation of temperature attenuation, gas evolution, and bifurcation influence for improved emergency response

The occurrence of underground mine fires remains a significant and persistent safety challenge in the mining industry, posing imminent risks to both miners' lives and the operational integrity of mining facilities. Current underground mine fire studies lack scale accuracy due to lab experiments and fail to consider bifurcation effects on smoke gas temperature. This study performed full-scale experiments and built validated CFD models to explore the interactive impact of ventilation and fire size on temperature attenuation, gas behavior, and CO generation in underground mines. A new empirical correlation for temperature decay in the mine drift was developed and its accuracy was compared with established models in the literature. In addition, the influence of bifurcation on maximum smoke temperature was analyzed. This research combines full-scale experiments and validated CFD modeling to address major gaps in underground mine fire studies. Unlike previous methods, this study explores the interactive effects of ventilation, fire size, temperature attenuation, and toxic gas spread, offering unprecedented insights. This innovation enables the development of tailored fire safety standards for mines, ensuring safer designs, rapid fire suppression, and improved evacuation strategies. By bridging theory and practice, this work transforms fundamental knowledge, empowering the mining industry to enhance safety measures, protect lives, and mitigate the impact of underground mine fires.

Gas–particle partitioning of semivolatile organic compounds when wildfire smoke comes to town

Abstract. Wildfires have become an increasingly important source of organic gases and particulate matter in the western USA. A large fraction of organic particulate matter emitted in wildfires is semivolatile, and the oxidation of organic gases in smoke can form lower-volatility products that then condense on smoke particulates. In this research, we measured the gas- and particle-phase concentrations of semivolatile organic compounds (SVOCs) during the 2017 northern California wildfires in a downwind urban area, using semivolatile thermal desorption aerosol gas chromatography (SV-TAG), and measured SVOCs in a rural site affected by biomass burning using cTAG (comprehensive thermal desorption aerosol gas chromatography mass spectrometry) in Idaho in 2018. Commonly used biomass burning markers such as levoglucosan, mannosan, and nitrocatechols were found to stay predominantly in the particle phase, even when the ambient organic aerosol (OA) was relatively low. The phase partitioning of SVOCs is observed to be dependent on their saturation vapor pressure, while the equilibrium absorption model underpredicts the particle-phase fraction of most of the compounds measured. Wildfire organic aerosol enhanced the condensation of polar compounds into the particle phase but not some nonpolar compounds, such as polycyclic aromatic hydrocarbons.

Numerical Simulation of the Ventilation and Fire Conditions in an Underground Garage with an Induced Ventilation System

The increasing quantity of air pollutants generated by automobiles can cause significant harm in relatively enclosed indoor environments. Studying the distribution of pollutants under different conditions in underground parking garages is of great significance for improving indoor air quality and reducing casualties in the event of a fire. This article presents a geometric model of an underground parking garage based on PHOENICS modeling. The related results of CO concentration distribution and fire temperature distribution under ventilation and fire conditions are obtained. Based on the CO concentration and velocity distribution as well as the temperature distribution during a fire, reasonable suggestions are proposed to improve indoor air quality and reduce casualty rates in fire incidents. The results show that under ventilation conditions, adjusting the position of the induced ventilation fan can maintain CO concentrations below 30 ppm in partitions one to three and below 37 ppm in partitions four to six. The temperature of smoke gases remained below 50 °C during the evacuation time, and only a small area exhibited CO levels exceeding 2000 ppm. The existing ventilation exhaust system provides effective fire protection, as it minimally affects personnel evacuation due to the relatively lower smoke temperature.

Smoke toxicity to the biota and the biological activity of soils when modeling fires

The paper presents the results of our study on the effect of one type of pyrogenic factor (smoke) after burning coniferous wood chips on several bioindicators (soil enzymes, microorganisms, mesofauna, plants of agricultural crops). Exposition to smoke for 60 minutes was found to significantly affect the enzymatic activity of common chernozem. Fumigation caused a decrease in such enzymes as catalase, peroxidase, polyphenol oxidase and invertase. The enzymes of the oxidoreductase class were the most sensitive to smoke. High toxicity of gaseous combustion products to the soil flora and fauna was revealed. The acute toxicity of smoke to the bioindicators was determined as a result of fumigation. High mortality of test objects (Eisenia fetida, Nauphoeta cinerea) was recorded in our experiments. Soil microorganisms (Azotobacter chroococcum and Penicillium chrysogenum) proved to be informative after 30–120 minutes of fumigation. Resistance of plant sprouts (Raphanus sativus, Triticum aestivum, and Pisum sativum) to combustion gaseous products was revealed. An experiment to analyze the chemical composition of gases in smoke was performed. Such hazardous compounds as sulphur dioxide (SO2), nitrogen oxide and dioxide (NO, NO2), carbon monoxide (CO), acetaldehyde (C2H4O), formaldehyde (CH2O), phenol (C6H6O) hydroxybenzene and others were found to be contained therein. Our analysis revealed that the concentrations of carbon monoxide were 714 times higher than its maximum permissible concentration (MPC), which acetaldehyde was 24,100 times higher. The nitrogen oxide and nitrogen dioxide concentrations were 100 and 300 times higher, respectively.

Protein kinase Cβ is involved in cigarette smoke gas phase-induced ferroptosis in J774 macrophages

Cigarette smoking is a risk factor for respiratory infection caused by immune cell dysfunction. Cigarette smoke is divided into tar and gas phases. Although the gas phase induces cell death in various cell types, the mechanism for gas phase-induced cell death remains to be clarified. In this study, we have examined the effects of cigarette smoke gas phase on J774 macrophages. Cigarette smoke gas phase and cytotoxic factors in the gas phase induced protein kinase C (PKC)-dependent ferroptosis. Pharmacological studies using isoform-specific PKC inhibitors have revealed that PKCβ is involved in cigarette smoke gas phase-induced ferroptosis in J774 macrophages.

SiO2/MOFs-based synergistic flame retardants provide enhanced fire safety for epoxy resins

To improve the inherent flammability of epoxy resin (EP), a new synergistic flame retardant (SiO2/PANI/ZIF-67) with silica, polyaniline (PANI) and zeolitic imidazolate framework-67 (ZIF-67) was synthesized successfully via an electrostatic interaction and chemical bonding technique. With the addition of 6% SiO2/PANI/ZIF-67, the limiting oxygen index (LOI) of as-obtained EP composite reaches up to 28.0%. The total heat release (THR), total smoke production (TSP) and total CO production (TCOP) of the composite are significantly decreased to 44.06%, 45.05% and 44.05% respectively. The synergistic role of SiO2, PANI and ZIF-67 induces formation of a dense SiO2-C layer, which greatly reduces emission of smoke gas and heat, and subsequently increases the fire safety of EP. Furthermore, the presence of organic-inorganic hybrid ZIF-67 on surface of flame retardant leads to its strong interface adhesion and well dispersibility in EP matrix. This work provides a simple route for designing and preparation of SiO2/MOFs-based synergistic flame retardants, which is of great significance to improve fire safety of epoxy resins.

Design and Build a Hazardous Gas Monitoring Device (CO, CO2, CH4) Upon Cigarette Smoke in an Enclosed Space Based on Arduino Uno and GSM SIM 900 A

Increasing cigarette usage in daily activities contributes to air pollution caused by cigarette smoke, which is a factor in the onset of numerous respiratory ailments. This research intends to develop a technology that will simplify users' monitoring of hazardous gases (CO, CO2, and CH4) levels in a room using Arduino Uno and GSM SIM 900A with MQ-4, MQ-9, and MQ-135 sensors. The method comprises hardware design, software design, and testing. The research was performed twice. The testing gas employed in this research is cigarette smoke gas. The red LED, fan, and buzzer turn on when the CH4 gas level reaches 250, the CO level reaches 300, or the CO2 gas level reaches 2000. A GSM SIM 900A sends a short message through SMS to the user's device. The initial test results were acquired in the 240th second when CH4 gas reached 299.84 299.84 ppm (hazardous), CO reached 310.06 ppm 299.84 ppm (hazardous), and CO2 reached 291.45 ppm (safe). The second test revealed that at 160 seconds, CO2 reached 308.98 ppm (hazardous), CO reached 161 ppm, and CH4 reached 315.6 ppm (hazardous). Three media specialists conducted validation to determine the viability. The average category rating for the validation test findings was 95.5% so that the instrument can monitor the room's gas levels.

Thermal Insulation and Flame Retardancy of the Hydroxyapatite Nanorods/Sodium Alginate Composite Aerogel with a Double-Crosslinked Structure.

As advanced thermal management materials, aerogels have great research value in the fields of engineering insulation, pipeline transportation, and packaging insulation. The composite interaction of the two-phase interface and the construction of a porous structure have an important impact on the thermal properties. Herein, a novel HANRs/SAB composite aerogel was prepared using sodium alginate (SA) with hydroxyapatite nanorods (HANRs), combined with boric acid crosslinking and freeze drying. In the prepared sample, the calcium ions in HANRs and SA formed the first layer of binding force and the chemical crosslinking of sodium alginate with boric acid formed the second layer of strong binding force, which effectively supported the skeleton of the aerogel and enhanced the overall mechanical properties. The modulus and maximum compressive strength of the obtained HANRs/SAB aerogel were 2.39 and 0.75 MPa, respectively, while the bulk density was 0.038-0.068 g·cm-3. Based on the prominent physical structure, the as-prepared HANRs/SAB aerogel exhibited good thermal insulation (∼35.15 mW·m-1·K-1) and outstanding flame retardant performance. Flame-retardant boric acid and high-thermal stability HANRs could effectively prevent heat transfer and organic combustion, thus resulting in an extremely low smoke gas release (11.3 m2 m-2). Therefore, the low-cost biopolymer composite aerogel based on a crosslinking strategy has broad application prospects in the field of thermal insulation and flame retardancy.

Reaction‐to‐fire testing of bus interior materials: Assessing burning behaviour and smoke gas toxicity

AbstractAlthough fire safety regulations for buses have been adapted in recent years regarding, for example, fire detection and engine fire suppression systems, the changes in regulations for bus interior materials are minimal. A comparison of fire safety regulations for interior materials in other transport sectors for trains, ships or aircraft reveals a much lower level of requirements for bus materials. Although repeated bus accidents as well as fire statistics show the danger a bus fire can pose to passengers. In particular, the combination of a fire incident and passengers with reduced mobility led to severe disasters in Germany and other European countries. To enhance the fire safety for passengers, the interior bus materials are crucial as the fire development in the bus cabin determines whether escape and rescue is possible. Against this background, bus interior materials were tested in different fire test scenarios. Measurement of a wide variety of parameters, for example, the mass loss, ignition time, smoke gas composition, heat release rate among others were carried out. Tested materials complied to the newest set of requirements. For this purpose, interior materials and their components had to be identified according to their chemical structure. Parts of the tests were funded by BASt (Federal Highway Research Institute) in the project 82.0723/2018. Experimental results show reaction‐to‐fire behaviour which lead to very limited times for escape and rescue in case of fire in a bus cabin. Based on the studies on fire behaviour and toxicity assessment, recommendations for improved fire safety regulations for interior materials could be made.

Evaluation of smoke gas toxicity and smoke density of bus interior materials

AbstractMaterials used for interior parts in buses are today fire classified according to UNECE Regulation 118, evaluating the horizontal and vertical burning rates and the melting behaviour. However, in recent accidents, the smoke has been identified as the critical parameter for deaths. An evaluation has been made of six materials used as interior parts in busses and is presented in this paper. Fire testing was conducted according to UNECE R 118 and smoke production including smoke gas toxicity was further evaluated with the smoke chamber test, EN ISO 5659‐2 and EN 17084. All six tested materials fulfilled the requirements of UNECE R 118; however, most materials showed fire properties which are not desirable, such as dark smoke and melting of large burning pieces. The tests with the smoke chamber showed that all materials gave a very high smoke production, in fact a smoke density value of the highest possible for the equipment to measure. This occurred only after a few minutes of test time. Thus, it can be concluded that this high smoke production will, in case of fire in a bus, reduce the visibility, and limit the ability of the passengers to safely evacuate. In addition, several toxic gases were detected in the smoke, both irritants and suffocating gases.

Proteome analysis of urinary biomarkers in a cigarette smoke-induced COPD rat model

BackgroundChronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease caused by inhalation of cigarette smoke (CS) and other harmful gases and particles.MethodsThis study aimed to explore potential urinary biomarkers for CS-induced COPD based on LC–MS/MS analysis.ResultsA total of 340 urinary proteins were identified, of which 79 were significantly changed (30, 31, and 37 at week 2, 4 and 8, respectively). GO annotation of the differential urinary proteins revealed that acute-phase response, response to organic cyclic compounds, complement activation classical pathway, and response to lead ion were significantly enriched at week 2 and 4. Another four processes were only enriched at week 8, namely response to oxidative stress, positive regulation of cell proliferation, thyroid hormone generation, and positive regulation of apoptotic process. The PPI network indicated that these differential proteins were biologically connected in CS-exposed rats. Of the 79 differential proteins in CS-exposed rats, 56 had human orthologs. Seven proteins that had changed at week 2 and 4 when there were no changes of pulmonary function and pathological morphology were verified as potential biomarkers for early screening of CS-induced COPD by proteomic analysis. Another six proteins that changed at week 8 when obvious airflow obstruction was detected were verified as potential biomarkers for prognostic assessment of CS-induced COPD.ConclusionsThese results reveal that the urinary proteome could sensitively reflect pathological changes in CS-exposed rats, and provide valuable clues for exploring COPD biomarkers.

Sistem Pemadam Kebakaran Otomatis Berkonsep Smarthouse

Home fire disasters are still common around us. This problem is a challenge in order to be able to find a solution. One solution to secure a home from a potential fire is to apply smarthome technology. Based on this problem, the idea arose to make an automatic fire extinguisher that can spray water with a water pump when it detects smoke (CO) due to a fire and circulates air in the room with an exhaust fan when an LPG gas cylinder leak is detected in the house so as to prevent a house fire. This tool is planned to be connected to the GSM module so that wherever we are we can find out if there is a fire in our home. This tool is made by utilizing the Smoke Gas Sensor (MQ 2), Temperature Sensor (LM35), Arduino Uno, GSM SIM 900 Module, Relay, Buzer, Exhaust Fan and Water Pump as its main components. Arduino Uno is used as the controller of this machine. The GSM SIM 900 Shield module is used for connection via SMS as a remote notification notification, LM35 as a temperature detector, and MQ 2 as a butane gas detector when there is a leak of LPG gas cylinders and fire smoke (CO) when a fire occurs. This tool can extinguish fires using a water pump from the detection of smoke (CO) and temperatures when more than 500 ppm and 40oC and circulate air using an exhaust fan with additional safety features when there is an LPG gas leak when gas is detected 500 ppm and send it with notification notification via SMS using the GSM SIM 900 module Shield. The measured voltage of the MQ2 sensor when clean air reaches 189.3 mV and the percent error of the LM35 reaches 0.88423%.

MESIN PEMBAKARAN PIROLISIS BERBAHAN DASAR SEKAM PADI DAN SABUT KELAPA PENGHASIL ASAP CAIR

This study aims to obtain smoke gas through pyrolysis technology byprocessing biomass materials around us, as well as knowing the effect ofincreasing the pyrolysator temperature on the capacity of the smoke gasproduced and the content in the biomass smoke gas. The combustion processin the combustion tube uses the pyrolysis method or combustion with lowoxygen levels or does not use oxygen. This second concept uses additionaldistillation methods to improve the quality of the liquid smoke produced. Thethird product concept has a combined design of the two previous concepts. Thisthird concept uses the concept of three phase changes using two condensertubes and one distillation tube.