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Background: Common causes of air leakage around an endotracheal tube include insufficient endotracheal tube cuff inflation and damage to the cuff, while damage to the pilot balloon or pilot balloon tubing is relatively rare. Case presentation: A 74-year-old female with vertebral osteomyelitis was scheduled for an extreme lateral interbody fusion followed posterior fixation. A fiber-optic light was utilized as part of the surgical illuminator. A sudden decrease in tidal volume and airway pressure was noted intraoperatively. We suspected leakage around the endotracheal tube cuff; however, no decrease in cuff pressure was detected. Despite the normal cuff pressure, we decided to inject a small amount of air which led to a significant increase in the cuff pressure. Upon careful inspection of the endotracheal tube, we discovered that the pilot balloon tubing was damaged as a result of thermal energy emitted by the fiber-optic light, which had ignited the surgical drape. The pilot balloon tubing was partially severed in which the section proximal to the endotracheal tube cuff was burned and punctured, causing the cuff leak. Meanwhile, the section proximal to the pilot balloon had melted and occluded the lumen, resulting in a falsely normal cuff pressure reading followed by an elevated cuff pressure when a small amount of air was injected into the pilot balloon during troubleshooting. Appropriate ventilation was resumed after extubation and re-intubation with a new endotracheal tube. Conclusions: We experienced an endotracheal tube cuff leakage caused by a damaged pilot balloon tubing due to thermal energy of the fiber-optic light. Our case report emphasizes the importance of suspecting damage to the endotracheal tube cuff and inflation system despite a normal cuff pressure reading, given that the measurement may be falsely elevated depending on the specific location of the damage. In addition, all operating personnel should be familiarized with safety warnings and cautions related to handling. [ABSTRACT FROM AUTHOR]

Abstract Background Common causes of air leakage around an endotracheal tube include insufficient endotracheal tube cuff inflation and damage to the cuff, while damage to the pilot balloon or pilot balloon tubing is relatively rare. Case presentation A 74-year-old female with vertebral osteomyelitis was scheduled for an extreme lateral interbody fusion followed posterior fixation. A fiber-optic light was utilized as part of the surgical illuminator. A sudden decrease in tidal volume and airway pressure was noted intraoperatively. We suspected leakage around the endotracheal tube cuff; however, no decrease in cuff pressure was detected. Despite the normal cuff pressure, we decided to inject a small amount of air which led to a significant increase in the cuff pressure. Upon careful inspection of the endotracheal tube, we discovered that the pilot balloon tubing was damaged as a result of thermal energy emitted by the fiber-optic light, which had ignited the surgical drape. The pilot balloon tubing was partially severed in which the section proximal to the endotracheal tube cuff was burned and punctured, causing the cuff leak. Meanwhile, the section proximal to the pilot balloon had melted and occluded the lumen, resulting in a falsely normal cuff pressure reading followed by an elevated cuff pressure when a small amount of air was injected into the pilot balloon during troubleshooting. Appropriate ventilation was resumed after extubation and re-intubation with a new endotracheal tube. Conclusions We experienced an endotracheal tube cuff leakage caused by a damaged pilot balloon tubing due to thermal energy of the fiber-optic light. Our case report emphasizes the importance of suspecting damage to the endotracheal tube cuff and inflation system despite a normal cuff pressure reading, given that the measurement may be falsely elevated depending on the specific location of the damage. In addition, all operating personnel should be familiarized with safety warnings and cautions related to handling.

Mine coal spontaneous combustion is one of the five major natural disasters in coal mines, and determining the concealed fire source locations of coal spontaneous combustion is key to solving the problem. This paper determines the thermal conductivity of coal samples through a spherical heat conduction model, and based on experimental data, analyzes the fitting relationship between thermal conductivity and heating voltage, the outer wall temperature of the inner sphere, and the location of high-temperature points under different voltage conditions. The study concludes that there is a linear relationship between thermal conductivity and both heating voltage and outer wall temperature, with a correlation coefficient greater than 0.9. In ideal conditions, the highest temperature is located at the center of the flat wall of the spherical heat conduction model. This re-search provides a mathematical basis for the prevention and control of mine coal spontaneous combustion fires. [ABSTRACT FROM AUTHOR]

Objective Fire accidents are major safety hazards in metro operation. To reduce fire hazards to an acceptable level and ensure the safe operation of trains, the research is specifically carried out. Method The safety analysis method outlined in EN 50126-2:2017 (Railway Applications – The Specification and Demonstration of Reliability, Availability, Maintainability, and Safety (RAMS) –Part 2: Systems Approach to Safety) is applied to analyze fire hazards in urban rail transit vehicle. Fire hazard lists for each system are established by identifying ignition sources and combustible materials. Using the HAZOP (hazard and operability analysis) method, components contributing to fire incidents are analyzed in detail to identify the causes of fires. Fire hazard identification is carried out in different scenarios during vehicle design, proposing mitigation measures, and tracking risk management measures until the risks are reduced to an acceptable level. Result & Conclusion The identified fire areas from the analysis of fire hazards in metro vehicles are applied to the scenario schemes of fire simulation analysis. The simulation results are used to further refine the fire hazard areas in metro vehicles, and the research results are applied to the design of fire alarm systems, enabling a more reasonable arrangement of fire alarm detection.

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Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Safety characteristics are used to keep processes, including flammable gases, vapors, and combustible dusts, safe. In the standards for the determination of safety characteristics of gases and vapors, the induction spark is commonly used. However, classic transformers are hard to obtain, and replacement with new electronic transformers is not explicitly allowed in the standards. This article presents the investigation of five gases that are normally used to calibrate devices for the determination of safety characteristics, the maximum experimental safe gap (MESG), with an electronic transformer, and the values are compared to the ones that are obtained with the standard transformer. Additionally, calorimetric measurements on the net energy of both ignition sources were performed as well as open-circuit voltage measurements. It is concluded that the classic type of transformer can be replaced by the new type obtaining the same results for the MESG and introducing the same amount of energy into the system.

Safety characteristics are used to keep processes, including flammable gases, vapors, and combustible dusts, safe. In the standards for the determination of safety characteristics of gases and vapors, the induction spark is commonly used. However, classic transformers are hard to obtain, and replacement with new electronic transformers is not explicitly allowed in the standards. This article presents the investigation of five gases that are normally used to calibrate devices for the determination of safety characteristics, the maximum experimental safe gap (MESG), with an electronic transformer, and the values are compared to the ones that are obtained with the standard transformer. Additionally, calorimetric measurements on the net energy of both ignition sources were performed as well as open-circuit voltage measurements. It is concluded that the classic type of transformer can be replaced by the new type obtaining the same results for the MESG and introducing the same amount of energy into the system. [ABSTRACT FROM AUTHOR]

Flameproof enclosures are widely installed as safety equipment at dangerous industrial sites to reduce ignition risks. However, electrical components typically installed in such flameproof enclosures for the production process can cause ignition and compromise the safety of the enclosures. Thus, in such cases, the explosive characteristics of the flameproof enclosures is severely affected. Accidental gas explosions in industrial sites rarely occur under standard operating conditions. Premixed gas explosions in flameproof shells are complex processes. A 560 mm × 400 mm × 280 mm flameproof enclosure commonly used in industrial sites was used to investigate the phenomenon. The explosion characteristics of ethylene-air premixed gas in the flameproof enclosure was simulated using FLUENT software to investigate the influences of ignition source location, ignition source energy, ambient temperature, and obstacles on the maximum explosion pressure, maximum explosion pressure rise rate, and maximum explosion index of the flameproof enclosure. The results revealed that the surface area of heat exchange considerably influences the maximum explosion pressure of the flameproof enclosure. The larger the ignition energy is, the larger the maximum explosion pressure value, the maximum rate of explosion pressure rise, and the maximum explosion index of the flameproof enclosure are. With the increase in the ambient temperature, the maximum explosion pressure decreased, whereas the maximum rate of explosion pressure rise and the maximum explosion index exhibited limited change. The results of this study provide theoretical guidance for the design and suppression of flameproof enclosures. [ABSTRACT FROM AUTHOR]

The complexity and concealment of the goaf environment hinder the understanding of the types of ignition sources in goaf gas explosions. Therefore, this study constructed a mechanical-electrical test system for rocks; the generation of pressure stimulated currents (PSCs) and its discharge-induced ignition mechanism of roof sandstone under uniaxial compression were explored, and the real ignition source of the gas explosion accident in Babao Coal Mine was revealed. The experimental results reveal that the intensity of PSCs of sandstone is higher than that of marble in the loading stage because the piezoelectric effect of quartz in sandstone enhances its mechanical-electrical sensitivity and leads to an increase in the discharge intensity. During the whole loading stage, the PSCs signals generated by sandstone are mainly attributable to the piezoelectric effect of quartz, while the PSCs of marble are mainly caused by the sliding friction between mineral particles. When the samples are in the compaction and elastic stages, PSCs are proportional to strain rate and stress rate respectively; when the samples enter the stage of plastic deformation and failure, the peak values of PSCs are positively correlated with the uniaxial compressive strength. Sparks can be seen in sandstone during the failure stage, which mainly results from electron avalanche caused by the damage of quartz grains under loading. The ignition source of the gas explosion accident in Babao Coal Mine is more likely to be sparks generated by the combined discharge of the extrusion friction and piezoelectric effect of roof sandstone, rather than coal spontaneous combustion. [ABSTRACT FROM AUTHOR]

Copyright of Transactions the Japan Society of Refrigerating & Air Conditioning Engineers is the property of Japan Society of Refrigerating & Air Conditioning Engineers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article addresses the issues of the particular terminology for fire forensic investigations. Definitions for the basic parameters of a fire hazardous area, determining its susceptibility to ignition, and their relationship to the impulses initiating such areas’ combustion are analyzed.Two main tasks of forensic fire examinations are reviewed: establishing the technical cause of a fire, its organizational cause, and consequences. The author gives definitions for these tasks and the term “ignition source”.The paper’s relevance stems from the need to prevent mistakes in terminology when conducting a forensic fire investigation. The article may be of use for practicing experts and specialists in fire forensics’ theory and practice.

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. [ABSTRACT FROM AUTHOR]

Being one of the most important industries in Ukraine oil and fat production enlists more than 1,200 enterprises involved in the production of oils, margarine and processing of raw material. Considering that the overall gross yield of oilseeds is growing every year, issues related to fire safety during transportation, storage and processing are to be studied. The research deals with the causes of fires at the enterprises of oil and fat production. Among the production processes resulting in increased fire danger are as follows: storage and transportation of raw materials and oil; the process of cleaning, caving, pressing the material; storage, transportation of auxiliary materials; refining and deodorization of fats; dry and wet-heat processing of raw materials, etc. The necessity to ensure the safety of area and production facilities, safe operation of the equipment and organization technological processes, the protection of workers from harmful and dangerous production factors, maintenance of production facilities and jobs caused by using fire and explosive substances and materials which under certain conditions (temperature, pressure, concentration of dangerous substances, etc.) can cause spontaneous ignition and combustion. We have estimated that the process of drying or conditioning of seeds increased fire danger. Consequently this process is accompanied by subsidence and the accumulation of raw materials on pits roughnesses, ducts, augers, and places of their connections. We have concluded that technological equipment, vehicles, pipelines, and valves are explosive places where under related conditions like heat or open flame spontaneous combustion, fire and explosion may occur and therefore the destruction of equipment, structures and buildings follow. In conclusion, we propose some measures to enhance the fire safety of the enterprises of oil and fat production, namely: control system, alarm system, regulation of processes, the protection and blocking dangerous technological units, start and stop (emergency) of equipment, etc.

The temperature, velocity, and size of hot metal sparks are essential to understanding their ability to ignite flammable materials. However, existing measurement methods have limitations to achieve detailed, in situ measurements of these parameters. This paper describes a methodology that combines color-ratio pyrometry and particle streak tracing velocimetry, together with digital image processing to obtain non-intrusive measurements of the temperature, velocity, and size of multiple sparks in a spray. Furthermore, these measurements can be performed using a properly calibrated commercially available color digital camera. The principle of the measurement is firstly introduced, and the repeatability and accuracy of the method are validated via a designed experiment. Then the method is performed to measure the temperature and velocity of metal (steel) sparks in sprays generated by abrasive cutting. Measurements of initial spark temperatures and velocities are reported, as well as the evolution of the temperature and velocity along the flight path of the sparks. Observed initial spark temperature in this work mostly ranged within 1500°C to 1700°C. Results show evidence of both melting and oxidation of the sparks. Different blade speeds are used to understand their effect on spark velocity and temperature. The results of this study can be used as input parameters for spark oxidation and transport models, which in turn can be used to assess the hazards of spark sprays in wildland spot fires, ignition, explosions of flammable gaseous mixtures and dust clouds, and for monitoring and optimizing the material processes such as thermal-spray coating. [ABSTRACT FROM AUTHOR]

The types of ignition sources in coal mines have complicated diversity and susceptibility due to the environmental complexity in the coal mine production process. To determine the actual ignition cause of a potential accident scene and prevent the occurrence of gas explosions, this work provides a new risk analysis method for mine ignition source based on the fuzzy Bayesian network (FBN). The first step relates to risk factor analysis and the BN model establishment. In light of the expert group decision-making method, risk topological structural models of ignition sources are constructed. The second step is fuzzification and defuzzification. To ensure the reliability of data in the process of expert investigation, this study proposes to calculate the weights of experts using a fuzzy analytic hierarchy process (FAHP) method based on subjective and objective expert weights. The last step uses causal reasoning, logical reasoning and sensitivity analysis to calculate the probability of occurrence of potential risk events and the probability distribution of risk factors. Through the case study of Babao Coal Mine in China, it is demonstrated that the FBN simulation provides a feasible method for accurately identifying the cause of gas explosion ignition. The proposed model can be used by analysts and decision-makers in the coal mine as a decision support tool to increase the probability of the ignition source in complex environments. [ABSTRACT FROM AUTHOR]

The types of ignition sources in coal mines have complicated diversity and susceptibility due to the environmental complexity in the coal mine production process. To determine the actual ignition cause of a potential accident scene and prevent the occurrence of gas explosions, this work provides a new risk analysis method for mine ignition source based on the fuzzy Bayesian network (FBN). The first step relates to risk factor analysis and the BN model establishment. In light of the expert group decision- making method, risk topological structural models of ignition sources are constructed. The second step is fuzzification and defuzzification. To ensure the reliability of data in the process of expert investigation, this study proposes to calculate the weights of experts using a fuzzy analytic hierarchy process (FAHP) method based on subjective and objective expert weights. The last step uses causal reasoning, logical reasoning and sensitivity analysis to calculate the probability of occurrence of potential risk events and the probability distribution of risk factors. Through the case study of Babao Coal Mine in China, it is demonstrated that the FBN simulation provides a feasible method for accurately identifying the cause of gas explosion ignition. The proposed model can be used by analysts and decision-makers in the coal mine as a decision support tool to increase the probability of the ignition source in complex environments. [ABSTRACT FROM AUTHOR]