Room Fire Research Articles

The impact of fire source location on hot gas layer temperature in multi-compartment pre-flashover fires: Analysis and semi-empirical model development

A numerical study of a two-room structure (multi-compartment) subjected to fire in the inner room was carried out, employing the CFD (Computational Fluid Dynamics) software called FDS (Fire Dynamics Simulator), to (i) analyze the influence of the fire source position on the hot gas layer temperature, Tu, and its behavior in a multi-compartment fire, and (ii) develop a semi-empirical engineering calculation model to predict Tu in the adjacent room to a pre-flashover well-ventilated fire room, taking into account the fire source position. The results showed that when the fire origin occurs close to walls or elevated above the floor level, a reduced air entrainment is observed in the fire plume and flame, causing an increase in the Tu and a reduction of the smoke production in the fire room. This reduction in the smoke production led to a lower increase in the Tu of the adjacent room in relation to the case when the fire source was at the center of the fire room. It was also observed that the Tu in both rooms was inversely proportional to the ventilation factor (A.H0.5), with a significant increase observed as the ventilation factor decreases, depending on the fire source position. Furthermore, a semi-empirical engineering calculation model was developed to predict the Tu in the adjacent room, considering different fire source locations at ground level and elevated. The model was validated against experimental data from the literature, showing a good agreement (deviation of ≈20 %), thus demonstrating its applicability to other cases.

Experimental study on the transitional behavior of the room fire under sub-atmospheric pressures

Fuel diffusion combustion and flame behavior within a confined space is a fundamental scientific problem in the energy and combustion field, it involves complicated chemical reaction, fire behavior, thermal dynamics, heat transfer, room-opening flowing and sub-processes of over-ventilated and under-ventilated room fire. However, previous classical knowledges and models about it are usually at standard atmospheric pressure (100 kPa), no work considers the fire evolution and flame behavior within the room for various sub-atmospheric pressures. In this paper, the experiment is carried by utilizing a 0.3 m × 0.3 m × 0.3 m reduced-scale cubic room with an opening of various dimensions, and using propane as fuel to simulate fuel combustion inside, which was placed at the Low Pressure Chamber creating various atmospheric pressures. The flame behavior and temperature evolution within the room was recorded and measured with 693 experimental conditions. The experimental results show that, (1) the air inflowing rate through opening into room and heat release rate within the room increase with atmospheric pressure; (2) the flame extinction or reaching well-mixed condition are more easily occurred for lower atmospheric pressure and opening dimension. These characteristic parameters and fire behaviors could be well described by new corrected opening ventilation factor involving effect of atmospheric pressure and the opening dimension. The research work fills the gap in basic scientific research of building fire at sub-atmospheric pressures, which also has important practical applicability of urban building fire protection design code (such as the materials in wall) in different altitudes, room fire suppression, and protecting urban safety.

An experimental study of fire development under varying ventilation conditions during the depressurization process in pressurized buildings

Hermetic pressurized buildings are a new type of building in high-altitude areas that efficiently addresses issues such as high-altitude reactions. The indoor pressure is higher than the external pressure under working conditions, and pressure relief must be carried out first during emergencies. The emergency pressure relief process during a fire may lead to complex fire behavior that is different from that in regular buildings. In this study, we focus on the impact of ventilation conditions and the status of doors in such buildings on fire evolution and smoke plume characteristics through experiments. The temperature variation in the fire room and corridor is measured under different ventilation power, ventilation time, and door opening width conditions. This shows that the width of the door has the greatest impact on fire development. A smaller gap in the door opening restricts air circulation between the interior and exterior of the room, resulting in a rapid decrease in the oxygen concentration within the fire room and a decrease in the combustion reaction rate of wood fires. The ventilation power exerts the most significant influence on the temperature variation in the corridor. These findings provide empirical data and a basis for fire science studies in high-altitude hermetic pressurized buildings and can guide existing fire protection design and management for improved safety.

Thermal runaway and combustion of lithium-ion batteries in engine room fires on oil/electric-powered ships

The thermal characteristics of traditional fuel fires can be altered by the thermal instability of lithium-ion batteries (LIBs) in–oil-electric hybrid ships. The thermal runaway (TR) and combustion of 18,650 LiFePO4 LIBs with 0 %, 50 %, and 100 % states of charge (SOC) in pool fires were studied with different annular n-heptane pools. The goal is to simulate the thermal safety of LIBs in hybrid ships within the thermal environment of pool fires. The flame morphologies resulting from the combustion of the battery and pool fires, temperatures of the battery surface and flame, exhaust characteristics of the battery, heat radiated from the pool fire to the battery, and mass losses were analyzed. The results showed that the risks of thermal runaway and combustion with LIBs were significantly higher in a thermal fire environment. Lithium batteries produce jet fires that increase the width and height of the flame during pool fires. Moreover, the battery with a 0 % SOC doesn’t experience thermal runaway during the fire, but thermal runaway of the battery with a 100 % SOC is more severe than that of the battery with a 50 % SOC, and the maximum rates for their temperature increases are 12.98 °C/s and 7.12 °C/s, respectively. In addition, the energy balance method showed that the pressure relief by the battery safety valve during a fire was not dependent on the SOC. An equivalent network diagram was constructed for the radiative heat transfer between the lithium battery and the pool fire. It is proposed that the total heats required to induce thermal runaway of batteries with the same SOCs are almost the same in different thermal environments, but the energy required for the 50 % SOC battery is greater than that required for the 100 % SOC battery, 10,161 ± 59 J and 9724 ± 43 J, respectively. Moreover, the combustion rates were proportional to the height of the flame during the mixed combustion of a lithium battery jet fire and pool fire. A dimensionless model was developed for the relationship between flame height and mixed combustion rate.

Theoretical model of the three - Stage parameter fire curve considering the contribution of combustible materials

Fire resistance is a critical factor constraining structural safety performance, specifically for Cross Laminated Timber (CLT) structures. Due to wood being a combustible material, the exposed wood will participate in combustion, increasing the fire load density and char rates, thereby causing more severe fire risks. In order to investigate the effect of exposed wood on fire temperature, this paper summarized 32 char rate data from 11 CLT room fire tests and fitted the relationship between wood exposure area and char rate, establishes a theoretical formula for the proportion of fire load burned outside the room to the total fire load, and it also establishes a theoretical formula for the three-stage parameter fire curve, which considers the contribution of combustible materials to fire load and char rate, as well as the transition from ventilation controlled to fuel controlled during the cooling stage of the fire. The accuracy of the three-stage parameter fire curve was verified through comparison with test results. Sensitivity analysis was conducted on the main parameters that affect the three-stage parameter fire curve. The results showed that the degree of influence of each factor on the maximum temperature of the fire and the time to reach the maximum temperature was as follows: fire load density > vent height > vent width > wood exposure area.

The Dreaded 3-Minute Wait: Does It Really Prevent Operating Room Fires? The IGNITE Trial

The Dreaded 3-Minute Wait: Does It Really Prevent Operating Room Fires? The IGNITE Trial

Risk evolution from causes to consequences of engine room fires on ships by mapping bow-tie into fuzzy Bayesian network

An integrated quantitative risk analysis methodology based on the BT (bow-tie) and FBN (fuzzy Bayesian network) is developed in the present study to evaluate the risk evolution from causes to consequences of engine room fires on ships. Given limited historical statistics on engine room fire accidents, a probabilistic estimation model based on fuzzy sets is employed to determine prior probabilities of BN nodes. A case study of the engine room fire is carried out to demonstrate the soundness and applicability of the proposed methodology. Moreover, scenario analysis is implemented to assess how safety barriers can mitigate escalation of consequences triggered by engine room fires, while sensitivity analysis ranks critical hazards and quantifies correlations between different consequences and risk events within engine room fires. The results indicate that mechanical faults, improper bunker operation, improper maintenance, circuit overload or short circuit and insulation aging or damage are the main direct risk events triggering engine room fires on ships. The effectiveness of safety barrier (fire extinguishing devices) can play a decisive role in preventing further escalation of controlled fire incidents.

Chemical and Thermal Exposure Risks in a Multi Compartment Training Structure

Providing NFPA 1403 compliant live-fire training can present thermal and chemical exposure risk to instructors and students. To reduce risk, training academies, fire departments, instructors, and standards setting technical committees need more information on how different training fuels used in common training structures can impact the environment in which firefighter training occurs. This study utilized a traditional concrete training structure with multiple compartments to characterize training environments with three different fuel package materials [i.e., low density wood fiberboard, oriented strand board (OSB), and wood pallets]. Exposure risks for a fire instructor located on either the first or second floor were characterized using measurements of heat flux, air temperature and airborne concentrations of several contaminants including known, probable, or possible carcinogens. It was hypothesized that utilizing a training fuel package with solid wood pallets would result in lower concentrations of these airborne contaminants [aldehydes, polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs)] than wood-based sheet goods containing additional resins and/or waxes. Additionally, it was hypothesized that these concentrations would be lower than in the single compartment Fire Behavior Lab presented in a companion manuscript. For all measured compounds other than hydrochloric acid, airborne concentrations were 10 to 100 times lower than in the Fire Behavior Lab. OSB-fueled fires produced the highest median concentrations of total PAHs and VOCs such as benzene, while the pallet fuel package produced the lowest median concentrations of these compounds. These trends generally followed the qualitative visual obscuration created by each fuel. Additional tests were conducted on the OSB-fueled fires with increased ventilation and an alternate means of reducing visibility through smoldering smoke barrels. This OSB experiment with increased ventilation resulted in the highest temperatures in the fire room but the lowest impact on visibility throughout the structure, as well as the lowest overall concentrations of contaminants in this study. In contrast, the smoldering straw-filled smoke barrel created a highly obscured environment (with minimal impact on thermal environment) and some of the highest concentrations of the targeted contaminants of any test. These data may be useful in balancing obscuration for training with potential exposure to thermal stressors and contaminants.

Experimental and numerical investigations of multi-layered ship engine room bulkhead insulation thermal performance under fire conditions

Abstract The thermal insulation layer of the ship’s engine room bulkhead is typically constructed from multiple layers of mineral wool. This layer is designed to keep the temperature on the surface of the bulkhead below 140°C in case of a fire. However, measuring the inner and external temperatures of each wall panel bulkhead type during a fire can be difficult. To address this issue, this study was conducted to evaluate the multilayer heat transfer capability of the bulkhead insulation in the event of an engine room fire. The study used heat transfer theory, experimental models, and numerical analysis to assess nine bulkhead insulation specimens. These specimens were fabricated from three original specimens and included a 10–30 mm air layer (W-75, W-50, and W-25). The results showed that all improved specimens had better thermal insulation than the originals. Among them, the improved specimens derived from the W-25 specimen exhibited the most significant temperature reduction compared to those derived from the W-75 and W-50 specimens. The results demonstrated a slight difference between the three methodologies, indicating a high level of reliability in the research findings.

Operating Room Fire Prevention: Video in Clinical Anesthesia.

Operating Room Fire Prevention: Video in Clinical Anesthesia.

Single Room Fire Traceability and Prediction Models Based on Deep Learning Methods

ABSTRACT When a fire occurs, fast recognition on key information of the fire based on limited data available and predict fire smoke motion trends from limited fire information is desirable to develop effective emergency strategies. The proposed models include fire intensity traceability model and fire position traceability model based on Back Propagation Neural Network (BPNN). Smoke prediction model is proposed based on Transpose Convolutional Neural Network (TCNN). The numerical model is first validated by the single-room fire test, and then a numerical database of 165 transient room-fire scenarios is established under various fire locations, fire sizes, and vent sizes. The model test is conducted in new fire intensity and vent size scenarios, with R2 coefficients of 0.965 and 0.95, respectively. The experimental data validation shows that relative errors were less than 10%. The position traceability model has Kappa values of 0.758 and 0.75. The average visibility error values of the smoke prediction model’s output images in the validation of the test set generally fall within the range of ± 1.5 m. The results indicate that the models have good accuracy and strong adaptability to different compartment fire scenarios which can provides effective support for fire rescue and emergency strategy development in fire scenes.

Analysis of Smoke Control System Performance of High-Rise Multifamily Residential Buildings Using Transient Simulation

In Korea, the general floor plan structure of multifamily residential buildings is such that the vestibules of stairs and fire service-access elevators are typically used together. The lobby of the emergency elevator faces the vestibules of the fire service-access elevators. The smoke control system supplies air for pressurization, and the inlet air discharge device for the exhaust can be exempted from this system. In a 49-story multifamily residential buildings with this structure, the smoke control system is operated at an outside temperature of −10 ℃ and indoor temperature of 20 ℃, and the fire room door is open. The possibility of the vertical spread of smoke owing to changes in the open areas of windows and escape elevator doors was analyzed. When the windows are closed, the vertical spread of smoke through the emergency elevator shaft and staircase may occur under both upper and lower fire conditions of the neutral zone. In particular, the flow path through the emergency elevator door is the main vertical spread path in the case of a fire below the neutral zone.

Preventing and Managing Operating Room Fires in Plastic Surgery: A Review of Incidence, Risk Factors, and Recommendations With Case Experiences.

Fires in operating rooms are rare yet devastating incidents. There are guidelines for the prevention and management of surgical fires; however, these recommendations are based on expert opinion and case reports. Almost all surgical procedures have an oxidizer (oxygen, nitrous oxide), an ignition source (such as a laser or "Bovie"), and a fuel, which together make up the 3 elements of an operating room fire. Our review analyzes each fire component to decide on the most effective clinical approach for reducing the risk of fire. We investigate the incidence, risk factors, legal repercussions, preventive strategies, and the precise management of fires in the operating room, with a particular focus on plastic surgery procedures. In addition, we share insights from our own experiences and propose guidelines based on our findings to enhance safety and response measures in surgical settings. Fires most commonly occur around the head, neck, and upper chest. High-risk procedures include tonsillectomies, tracheostomies, laryngoscopies, and facial/neck surgeries. Checklists help ensure proper precautions are taken, such as using moist towels and lowering oxygen concentration. If a fire erupts, prompt removal of the oxygen source and irrigation is critical. From our experience, fires spread rapidly and can cause severe burns and inhalation injuries. We share an illustrative case of a surgical fire at our institution. Our review underscores the importance of fire prevention and preparedness through safety protocols, equipment maintenance, staff training, and maintaining situational awareness. More research is needed to quantify risk factors and determine optimal management strategies when fires do occur.

On the causation analysis for hazards involved in the engine room fire-fighting system by integrating STPA and BN

A novel methodology is proposed in this study to investigate the hazards involved in the engine room fire-fighting system. In the proposed methodology, the fuzzy theory is applied to bridge the superiority of the systems theoretic process analysis (STPA) and Bayesian network (BN). The engine room fire-fighting system is initially audited within the framework of STPA qualitatively to identify unsafe control actions, and then, the causations contributing to these actions are determined, which are subsequently considered as the root nodes of the BN. To implementing Bayesian inference, the expert elicitation within fuzzy theory is employed to determine the probability distribution of the root nodes, and the conditional probability tables for intermediate nodes are obtained by leaky Noisy-OR function, based on which the developed BN is simulated. Finally, the results from BN simulation are interpretation from the perspectives of brief propagation analysis, sensitivity analysis and influence strength analysis. The proposed methodology can be applied to audit the integrity of engine room fire-fighting system to eliminate the potential causations contributing to engine room fire.

A Numerical Study on the Smoke Dispersion and Temperature Distribution of a Ship Engine Room Fire Based on OpenFOAM

To further study the smoke dispersion and the temperature distribution in ship engine room fires, the fire dynamics solver buoyantReactingFOAM in the software OpenFOAM-10 is used to conduct a numerical simulation study on a pool fire caused by fuel oil leakage in a ship engine room. The applicability of this solver in simulating ship-engine-room-scale fires is validated by comparing it with experimental data. The impact of the mechanical ventilation, fire area, and fire position on the smoke dispersion and the temperature distribution in the ship engine room during the fire are considered in the simulation study, with a focus on the control room and the escape exit. The simulation results of buoyantReactingFOAM agree well with the experimental data. The simulated results of the case study show that for both in the control room and near the escape exit, among the factors of fire position, fire area, and the ventilation situation, the fire position affects the temperature distribution and the smoke dispersion most heavily, followed by the fire area and then the ventilation situation, which has the least influence on them. But, compared to the control room, the influence degree of the ventilation air velocity in the escape exit is larger than that in the control room. With an increase in the fire area, the spread rate of high temperature and high smoke concentration increases. With an increase in the ventilation air velocity, the aggregation degree of smoke and temperature decreases, but its decreasing range is very small when the ventilation air velocity is larger than 2 m/s.

Utilization of virtual reality for operating room fire safety training: a randomized trial

Utilization of virtual reality for operating room fire safety training: a randomized trial

Eliminating scale effect: Development and attenuation of coal spontaneous combustion

Low temperature oxidation can occur in coal and coal piles, which can lead to severe fires in coal fields, storage rooms, and goaf areas. An important feature of these coal fire disasters is their large scale, providing a favorable environment for the inoculation of coal fires. A new method for studying coal oxidation reactions, which combines theoretical analysis with multi physical field numerical models, has been proposed to eliminate the influence of scale effects. Based on the theoretical analysis, the reliable numerical simulation conditions are obtained, and the results are compared with those of large coal spontaneous combustion experiment. The temperature, gas and reaction rate of coal oxidation have been analyzed and verified. The attenuation characteristics of coal oxidation reaction under sealed and nitrogen retarding measures have also been analyzed with emphasis. The research results indicate that the proposed new simulation method has been proven to be effective through multiple results validation. Sealing measures can weaken coal oxidation reactions, but heat elimination is slower. The measure of injecting nitrogen can quickly control local coal oxidation reactions and remove heat. The greater the flow rate of inert gas, the better the retarding effect on coal. The development process of coal oxidation will form “quasi spherical” and “crescent shaped”, which are prominent characteristics of slow oxidation and rapid propagation, respectively.

Comparative safety analysis of engine room fires with different marine fuels of MGO, LPG and H2

ABSTRACT This research project is designed to investigate the behaviour of fires resulting from hydrogen leakage in engine rooms and evaluate the associated fire risks, aiming to compare these risks with those posed by traditional fuels which can be used in the shipping industry today. The study employs a model of the engine room constructed according to the original dimensions of the vessel under study. The primary objective of this research was to determine if the fire risk associated with hydrogen would be higher or lower than that of traditional fuels. To achieve this, a series of simulation scenarios were meticulously executed and subsequently analysed. The outcomes of the simulations indicate that hydrogen fires do not present a higher threat when compared to fires fuelled by marine gas oil or liquefied petroleum gas. Notably, hydrogen exhibits superior fire behaviour, characterized by the absence of smoke development and relatively less harm to machinery and crew, thus outperforming conventional fuel fires. This finding suggests that hydrogen-related fire risks can be brought under control and highlights its potential as a comparatively safe fuel choice in the maritime domain.

Risk-informed Emergency Response Training for Backdraft in Nuclear Power Plants

Research has been conducted for developing fire evacuation and response training programs for nuclear power plant (NPP) application. Among numerous fire scenarios that may occur in an NPP environment, three different points of origin for a fire were selected for the program based on a risk-informed approach: switchgear room, main control room, and safety injection pump room. Fire outcomes were predicted for these scenarios via numerical modeling and the results were incorporated into the newly developed fire evacuation and response training program for the APR1400, Korea’s next-generation NPP model. The switchgear room fire scenario was found to have the most potential for backdraft to occur during manual fire response following automatic gaseous fire suppression system activation. The emergency response manual does discuss this possible backdraft occurrence; however, the guidance to avoid injuries is qualitative, such as to be cautious of backdrafts and wait a sufficient amount of time after opening a door before entering the. In this study, backdraft phenomenon that may occur from a switchgear room fire was numerically examined using the recent version of the Fire Dynamics Simulator to develop an appropriate timeline to be implemented in the fire evacuation and response training program. Based on the findings, the following guidance is provided: (1) backdraft can only occur when the fire originates in the space near the door; (2) wait at least 10 minutes after opening the door before entering the room; (3) watch for rapid smoke production, as this may be an antecedent phenomenon of backdraft; and (4) when smoke production increases rapidly, leave the room as soon as possible to avoid being caught within the deflagrating flames from a backdraft.

Effects of hydrogen isotope type on oxidation rates for trace releases

The fraction of tritium converted to the water form in a fire scenario is one of the metrics of greatest interest for radiological safety assessments. The conversion fraction is one of the prime variables contributing to the hazard assessment. This paper presents measurements of oxidation rates for the non-radioactive hydrogen isotopes (protium and deuterium) at sub-flammable concentrations that are typical of many of the most likely tritium release scenarios. These measurements are fit to a simplified 1-step kinetic rate expression, and the isotopic trends for protium and deuterium are extrapolated to produce a model appropriate for tritium. The effects of the new kinetic models are evaluated via CFD simulations of an ISO-9705 standard room fire that includes a trace release of hydrogen isotope (tritium), illustrating the high importance of the correct (measurement-based) kinetics to the outcome of the simulated conversion.