Room Fire Research Articles

Detecting Flashover in a Room Fire based on the Sequence of Thermal Infrared Images using Convolutional Neural Networks

Flashover phenomena accompanying rapid fire propagation in a room occur when the hot smoke from a fire accumulates in the room's upper part. This phenomenon presents one of the most frightening and challenging situations for firefighters. A typical approach to mitigate and prevent the impact of flashover is to train firefighters to monitor a few common indicators of fire in pre-flashover time, such as moving dark smoke, high heat, and fire rollover. In actual compartment fire events, these pre-flashover indicators are hard to recognize. Furthermore, determination of exact flashover time is difficult by just observing fire activities while there are other vital rescue duties to do by firefighters. Hence, automatic detection and prediction of flashover in real time are of paramount importance to save lives and reduce the cost of damages. Flashover prediction is still an open area of research by fire safety experts. Deep convolutional neural networks are currently dominating the area of computer vision, and these state-of-the-art deep learning models have been successfully used in various applications, including object detection, localization, and segmentation. Unlike previous studies that use RGB images, sensors, and gauges, we utilized the power of deep learning techniques to detect flashover from image sequences captured by thermal infrared (IR) cameras. Our experimental results indicate that not only our proposed approach can detect flashover in IR video data with high precision, but it can detect flashover a few frames before happening. Our technique is a promising approach that can be used in future for flashover prediction in real time.

Study on the Deformation Behaviour of Reinforced Concrete Beam-Supporting Column Transfer Structures during Fire Exposure

Considering that reinforced concrete beam-supporting column transfer structures are often large, it is difficult to perform experimental research on the whole structure. Therefore, in this paper, the key part of the transfer structure, namely, the beam-supporting column joint, is tested at high temperatures. These test results are verified through finite element analyses. The research object used in the finite element analyses is extended to the overall structure. The results of this research show that under symmetrical fire conditions, the overall deformation mode of the beam-supporting column transfer structure is symmetrical about the central axis of the structure. The deflection of the transfer girder and the corresponding beam segments of the upper beams increased to different degrees. The frame column produces bending deformation towards the outside of the frame, and the greatest deformation generally occurs in the fire floor. Under asymmetrical fire conditions, the overall deformation of the beam-supporting column transfer structure is asymmetrical about the central axis of the structure. The entire structure has a tendency to slope towards the side of the fire room. The deflection curve of the beams protrudes to the side of the fire room. This phenomenon is more obvious below the fire floor, whereas the deflection gradually declines from the lower floors to the upper floors.

The comparative evaluation of the criteria used to determine the critical values of the partial density of carbon monoxide as part of the calculation of time to the blocking of escape routes in case of a room fire

Introduction. Critical values of the partial density of gas, the toxic dose or relative mass of carboxyhemoglobin in human blood serve as the criteria determining the time to the blocking of escape routes due to the presence of carbon monoxide. However, the comparative analysis of the effect produced by the selected criterion on the time to the blocking of escape routes due to the presence of this gas has not been conducted yet.Goals and objectives. The purpose of the article is to compare the values of the time to the blocking of escape routes by carbon monoxide obtained using various methods of determining the critical values of the carbon monoxide density. Towards this end, experimental studies on combustion processes of various solid and liquid combustible substances and materials were conducted in a small-scale test unit, and calculations of the time to the blocking of escape routes with carbon monoxide were made on their basis.Theoretical fundamentals. The amount of carbon monoxide, inhaled during a fire, is calculated using experimentally measured partial densities of CO and mathematical models designated for the calculation of the toxic dose of this gas and formation of carboxyhemoglobin in human blood.Results and discussion. Experimental dependencies between the testing time and medium-volume densities of monoxide emitted during the combustion of the “low smoke” PVC cable sheathing, timber (pinewood), chocolate, transformer oil and vegetable oil are presented. The authors obtained theoretical dependencies between the toxic dose and mass concentration of carboxyhemoglobin in human blood, on the one hand, and the time for the combustible materials, analyzed in the article. It has been found that the values of time to the blocking of escape routes due to the presence of carbon monoxide may differ significantly depending on the method used to determine the critical values of the carbon monoxide density.Conclusions. Standard methods, used to calculate the time to the blocking of escape routes due to the presence of carbon monoxide, employ the value of the critical partial density which may involve a substantial overestimation of the above time frame and the underestimation of the toxic effect produced on a person in the process of his/her evacuation. Therefore, it is necessary to apply all methods, discussed in the article, to select the minimum value of the above time frame.

The Collapse of World Trade Center 7: Revisited

The catastrophic events of September 11, 2001, stand out as a major motivation for research on improving the understanding of structural behaviour in fire. These events included the first complete collapse of a tall steel framed structure solely due to fire. World Trade Center 7 (WTC7) was a 47-storey office building within the WTC complex that collapsed due to a fire initiated by debris from the collapse of WTC1. In the following years, detailed investigations were carried out by expert teams to pinpoint the cause of the progressive failure of WTC7. Each of the expert teams analysed the fire and structure and made varying conclusions with regards to the mechanisms responsible for initiating and propagating the collapse of the building. This paper revisits the collapse of WTC7 and its investigation, and then explores the hypothesis that a potential hydrocarbon fire may have compromised the large transfer structure within the mechanical space of the building. This is done via two OpenSees finite element models. The first model explores the thermomechanical response of the mechanical floors to a potential diesel fire, and the second investigates the response of the structure to a failure caused by that fire. The outcome of the analyses shows that it is feasible that a mechanical room fire could lead to a failure in the transfer structure, which would then result in the loss of support to at least two columns within the building core. The failure of these columns may unbrace the eastern-most core columns and precipitate in the failure of the structure as observed on 9/11.

Application of Key Technologies of Distributed Storage Based on the Internet of Things in Urban Fire Protection

Due to the rapid development of science and technology in the current era, fires occur more frequently, and the relationship between various economic activities and things is becoming more and more frequent. The need for real-time monitoring and remote monitoring of various firefighting facilities in buildings has become very urgent; this is a task that must be put on the agenda. The existing urban fire remote monitoring system has fewer intelligent networks, so it has high requirements for the firefighters on duty in the fire control room, which is no longer sufficient for the firefighting needs of the modern society. This paper proposes a wireless city fire remote monitoring system based on Internet of Things technology, NB-IoT technology, and cloud computing technology and studies core technologies such as designing wireless monitoring nodes at the perception layer. In the urban fire protection environment of distributed storage, several important theories, key technologies, and related algorithms are being studied in detail. After a variety of experimental verification results, the spatial data engine and adaptive spatial data model of the metadata database are developed. This provides a distributed storage virtual city geographic environment, multilevel, multiregional design and development of a simulated prototype platform and storage, management, sharing, and visualization of urban geospatial data. After technical analysis, a visualization framework was installed, which has the characteristics of global vector grid integration and distributed spatial data. Through the research on the key technology of distributed storage of the Internet of Things, this paper applies it to urban fire protection and promotes the intelligent development of urban fire protection. The application of IoT storage technology in urban fire protection can solve the shortcomings of the current urban fire remote monitoring system and automatic fire alarm system. Wireless city fire remote monitoring system, real-time collection, and transmission and storage of working status information of various fire facilities in the building are provided. The functions of real-time monitoring, real-time alarm, real-time search query, record query, maintenance management, route guidance, and user management are also realized.

Risk of airway fire with the use of KTP laser and high flow humidified oxygen delivery in a laryngeal surgery model

Airway surgery presents a unique environment for operating room fire to occur. This study aims to explore the factors of combustion when using KTP laser with high flow oxygen in an ex-vivo model. The variables tested were varying tissue type, tissue condition, oxygen concentration, laser setting, and smoke evacuation in a stainless-steel model. Outcome measures were time of lasing to the first spark and/or flame. A multivariate Cox proportional hazard model was used to determine the risk of spark and flame across the different risk factors. For every 10% increase in oxygen concentration above 60% the risk of flame increased by a factor of 2.3. Continuous laser setting at 2.6 W increased the risk by a factor of 72.8. The risk of lasing adipose tissue is 7.3 times higher than that of muscle. Charred tissue increases the risk of flame by a factor of 92.8. Flame occurred without a preceding spark 93.6% of the time. Using KTP laser in the pulsed mode with low wattages, minimising lasing time, reducing the oxygen concentration and avoiding lasing adipose or charred tissue produce a relatively low estimated risk of spark or flame.

Smoke filling and entrainment behaviors of fire in a sealed ship engine room

Firefighting by sealing the cabin is often served as a final-taken and efficient means of suppressing ship fire. When a fire occurs in a closed engine room, it could cause the internal pressure increased and the oxygen concentration decreased, which further affects the fire burning processes. The interaction between the combustion processes and the changing environment makes sealed fires even complicated. This study investigates the behaviors of smoke plume entrainment and filling in a sealed ship engine room. Theoretical models regarding the plume entrainment and smoke filling are developed, respectively. A new reverse analysis method by coupling particle swarm optimization (PSO) with the smoke filling model is proposed to determine the unknowns in the plume entrainment model. Based on the experimental data in the literature and the reverse analysis, the explicit smoke filling model of sealed ship engine room is developed. Several previous experimental measurements and numeric simulations are used to validate its prediction ability. The results also suggest that a sealed fire has a higher smoke entrainment level than an open case. The proposed sealed ship engine room fire model can be applied to the engineering safety design of cases with potential sealed fires.

Engine room fire safety evaluation of ammonia as marine fuel

ABSTRACT Ammonia fuelled vessels are not a distant reality anymore. This paper will examine whether ammonia constitutes a greater fire hazard than conventional fuel types in the event of an engine room fire. It is to showcase how a realistic engine room fire outbreak can be modelled for a case vessel of 50,000 dead weight tonnage bulk carrier. Four simulation scenarios are then modelled, and their outputs are analysed and discussed. From the simulations process, it was evident that an ammonia fire does not present a greater danger than a diesel or natural gas fire. Ammonia’s fire behaviour was better than the conventional fuel fires with relation to soot formation and potential machinery damage. An ammonia fire provides a better evacuation window; it has more even temperature distribution through the engine space and the developed flame temperatures were lower. The main conclusion of this project is that due to ammonia flammability limits and thermal properties, a dispersion would take time and thus reduce the likelihood of an ammonia fire occurring and is manageable.

Experimental study on the ignition characteristics of leaking RP-3 aviation kerosene on a horizontal hot wall

The accidental ignition of liquid fuels is an industrial safety concern due to the storage and transport of pressurized flammable liquids near components at elevated temperatures. In this work, the ignition process of leaked RP-3 aviation kerosene on the surface of the high temperature heat meter was studied experimentally and the critical temperature of the 50% ignition probability was obtained by the statistical method. The ignition process of fuel on horizontal hot wall was analysed by using the ignition video shot by high-speed camera, and the fuel steam plume model of the minimum hot surface ignition temperature for spilled fuel was established, which provided a theoretical basis for quantitative research on the ignition characteristics of leaking fuel on the hot surface. It shows that the temperature field and spatial concentration distribution produced by oil evaporation are time-varying and helpful for engine room fire protection. This study complements the related content of the fuel ignition mechanism on hot wall, at the same time, and provides fundamental understanding of the physical phenomena involved in the thermal ignition of impinging sprays in different regimes toward the goal of improved industrial safety.

Incidence of Operating Room Fires During Hand Surgical Procedures.

The purpose of the present study is to report the incidence of operating room fires during hand surgical procedures. The clinic and OR electronic medical records of seven fellowship-trained orthopedic hand surgeons at a single, large practice were retrospectively reviewed. All upper extremity procedures performed between June 2014 to June 2019 in both hospital and surgery center settings were included in the review. Demographic data was collected. The incidence of operating room fires was determined. A total of 18,819 hand and upper extremity surgical procedures were included. There were 16,767 (89.1%) cases performed in a surgery center, while 2,052 (10.9%) of cases were performed in a hospital. There were 12,691 (67.4%) soft tissue procedures and 6,127 (32.6%) bony procedures performed. Chlorhexidine gluconate preparation solution was used in 9607 cases (51%). Chloraprep solution was used in 6280 cases (33.4%). Betadine was used in 2,932 cases (15.6%). One surgeon has monopolar electrocautery only available during cases. Five surgeons have bipolar available, and one has both mono and bipolar electrocautery available. There were no fires (0%) identified during the study period. The incidence of operating room fires during hand surgical procedures is extremely low. While hand surgeons can be reassured that the likelihood of an operating room fire is minimal, surgeons should not become complacent and should maintain a high level of vigilance to prevent these potentially devastating occurences.

Operating room fires in otorhinolaryngology: a literature review

Operating room fires are potentially life-threatening events. Despite being casuistry, they are a real danger and their occurrence nowadays is mainly because the surgical team lacks knowledge on fire safety and deviates from current established practical recommendations for the prevention of such events. Interventions in otorhinolaryngology and head and neck surgery are associated with a particularly high risk of fire. This is due to the proximity of the components of the so-called fire triangle in these interventions. The most common causes and mechanisms of fire are well established—the main factor in otorhinolaryngology is the activation of an energy-based surgical instrument close to the endotracheal tube or in an oxygen-rich environment, and the majority of the accidents occur due to the lack of awareness of the functioning of the equipment used and the potential fire risk. However, the recommendations for fire prevention and algorithms for behaviour in cases of fire in the operating room are contradictory or incomplete. The lack of a unified strategy at a local, national or international level, as well as the lack of theoretical and practical training of the personnel involved in the surgical work lead to a large number of potentially preventable similar events, the real number of which could not be estimated because their registration is not mandatory and is usually undesirable due to potential legal risk.

Airborne contamination during post-fire investigations: Hot, warm and cold scenes

Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m3 (range 16–498 µg/m3) and median peak transient concentrations of 1,090 µg/m3 (range 200–23,700 µg/m3) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m3, range: 140–775 µg/m3) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators’ airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations.

Incidental operating room fire from a breathing circuit warmer system: a case report

BackgroundAn airway-associated fire in an operating room can have devastating consequences for patients. Breathing circuit warmers (BCWs) are widely used to provide heated and humidified anesthetic gases and eventually prevent hypothermia during general anesthesia. Herein, we describe a case of a BCW-related airway fire.Case presentationIn this case, an electrical short within a BCW wire caused a fire inside the circuit. Simultaneously, the fire was extinguished, ventilation was stopped, and the endotracheal tube was disconnected from the BCW. The patient was exposed to the fire for less than 10 s, resulting in burns to the trachea and bronchi. Immediately after airway burn, bronchoscopy showed no edema or narrowing except for soot in the trachea and both main bronchus. After the inhalation burn event, prophylactic antibiotics, bronchodilator, mucolytics nebulizer, and corticosteroid nebulizer were started. On bronchoscopy 3 days after the inhalation burn, mucosal erythematous edema was observed and the inflammatory reaction worsened. The inflammatory reaction showed aggravation for up to 2 weeks, and then gradually recovered, and the epithelium and mucous membrane of the upper respiratory tract returned to normal after 4 weeks. Eventually, the patient recovered without long-term complications and was successfully discharged.ConclusionsThis is the first report of a fire caused by BCW. We wanted to share our experience of how we responded to an airway-related fire in an OR and treated the patient. It cannot be overemphasized that the electrical medical appliance associated with the airways are fatal to the patient in the event of a fire, so caution should always be exercised.

Early fire detection based on gas sensor arrays: Multivariate calibration and validation

Smoldering fires are characterized by the production of early gas emissions that can include high levels of CO and Volatile Organic Compounds (VOCs) due to pyrolysis or thermal degradation. Nowadays, standalone CO sensors, smoke detectors, or a combination of these, are standard components for fire alarm systems. While gas sensor arrays together with pattern recognition techniques are a valuable alternative for early fire detection, in practice they have certain drawbacks—they can detect early gas emissions, but can show low immunity to nuisances, and sensor time drift can render calibration models obsolete. In this work, we explore the performance of a gas sensor array for detecting smoldering and plastic fires while ensuring the rejection of a set of nuisances. We conducted variety of fire and nuisance experiments in a validated standard fire room (240 m3). Using PLS-DA and SVM, we evaluate the performance of different multivariate calibration models for this dataset. We show that calibration models remain predictive after several months, but perfect performance is not achieved. For example, 4 months after calibration, a PLS-DA model provides 100% specificity and 85% sensitivity since the system has difficulties in detecting plastic fires, whose signatures are close to nuisance scenarios. Nevertheless, our results show that systems based on gas sensor arrays are able to provide faster fire alarm response than conventional smoke-based fire alarms. We also propose the use of small-scale fire experiments to increase the number of calibration conditions at a reduced cost. Our results show that this is an effective way to increase the performance of the model, even when evaluated on a standard fire room. Finally, the acquired datasets are made publicly available to the community (doi: 10.5281/zenodo.5643074).

Development of a machine-learning approach for identifying the stages of fire development in residential room fires

Recognizing the stages of fire development is essential for fire emergency operations. It allows firefighters to predict what will happen next, potential fire spreads, and the likely effect of tactical actions. Currently, firefighters recognize fire stages mainly by observing and judging the signs and symptoms of fire development changing on-site. However, this kind of approach highly relies on firefighters’ knowledge and experience, making it difficult to operate. Therefore, a machine learning (ML)-based approach automatically identifying the stages of fire development in residential room fires is proposed in this paper. Modeled by Gaussian Mixture Models and Hidden Markov Models (GMM-HMM), the approach enables identifying the stages of fire development from short-term field temperature collections. To provide adequate data for model training, the two-zone fire model— CFAST and a non-parametric fire design method are applied to generate the temperature observations in various random fire scenarios. Taking the fire in a typical single-story residential construction as a case study, we establish a GMM-HMM-based recognition model with the simulated temperature data. It presents an average of 85% accuracy in identifying the fire stages within the 2 min error range. Moreover, tested with the experimental fire data, the established model also achieves successful recognitions.

Catching Fire: Are Operating Room Fires a Concern in Orthopedics?

Operating room (OR) fires are considered "never events," but approximately 650 events occur annually in the United States. Our aim was to detail fires occurring during orthopedic procedures via a questionnaire because of the limited information present on this topic. A 25-question survey on witnessing surgical fires, hospital policies on surgical fires, and surgeons' perspective on OR fires was sent to 617 orthopedic surgeons in 18 institutions whose residency program is a member of the Collaborative Orthopaedic Educational Research Group. The response rate was 28%, with 172 surgeons having completed the survey. Twelve of the 172 orthopedic surgeons surveyed reported witnessing at least 1 surgical fire in an OR setting. Electrocautery was the leading ignition source, causing fires in 7 events. A saw, laser, and light source were reported to have caused 1 fire each. Regarding fuel source for the fires, bone cement was a common culprit (n = 4), followed by gauze (n = 3). Oxygen delivery to patients was via a closed system in most cases (n = 9). No patient harm was reported in any of these cases.Just under half of the respondents (47.7%) reported not receiving any formal OR fire prevention or response training. The most common answer for frequency of concern about a surgical fire was "never" (42.4%). Fires pose a risk in surgery, even in an orthopedics setting. Room oxygen can supply enough oxidizing power for a fire to occur, especially with the ubiquitous nature of ignition sources and fuels in the OR. Prevention is key with these events. Operating room personnel education must be sought, and surgeons should be mindful of the fire components in the OR.

Experimental Study on the Spread Characteristics of Initial Fires According to Corridor Types

During an accidental fire in buildings, the corridor becomes the path for flame and smoke to spread, exposing the occupants to danger. Therefore, this study conducted real-scale fire experiments using corridors of size 2.4(L) × 10(W) × 2.4(H) m an “L-type” corridor for one-way evacuation and a “T-type” corridor for two-way evacuation to analyze the characteristics of fire according to the shape of corridors. The real-scale fire experiments were conducted in a fire room (2.4(L) × 3.6(W) × 2.4(H) m) with a single opening (2.0(W) × 1.8(H) m). The combustibles used inside the fire room were wood cribs, with a heat release rate of 651.4 kW, in the L-type corridor and chairs, with a heat release rate of 95.7 kW, in the T-type corridor. The temperature inside the corridor was measured during the real-scale fire experiments, and the average maximum measured temperature was 432.1 °C in the L-type corridor and 103.5 °C in the T-type corridor. The experimental results and the ventilation characteristics according to the corridor types were applied to BFD curves to show the process of designing fire growth models according to corridor types.

Large eddy simulation of room fire spread using a medium scale compartment made of medium density fibreboard (MDF) panels

Large eddy simulation of room fire spread using a medium scale compartment made of medium density fibreboard (MDF) panels

Flame whirling characteristics of fire in a room with vent

SummaryVelocity distribution and motion of a whirling flame in a room fire with vent were studied analytically in this article. Using Rankine vortex model, whirling flame models with and without decay of the rotation velocity were established. The whirling flame model and the cross‐wind velocity boundary conditions were used to study the velocity distribution of the rotating flame under the action of side wind. When there is a linear velocity gradient in the lateral wind, the whirling flame still revolves around the same axis at different heights in the model without attenuation of rotation velocity, but the axis becomes tilted. In the rotation velocity attenuation model, the axis of the whirling flame changes from a straight line to a curve, and the change of the shape of the whirling flame is related to the flame height, the rotation angular velocity, and the maximum wind velocity. Under the assumption of Rankine vortex model with the same rotation angular velocity, the uniform lateral wind and lateral wind with linear velocity gradient can only affect the position and shape of the whirling flame axis but not change the rotation angular velocity.

Large eddy fire simulation applications from nuclear industry

Abstract A computational study has been carried out for predicting the behaviour of a pool fire source using the field-model based code Fire Dynamics Simulator (FDS). Time dependent velocity and temperature fields are predicted along with the resulting changes in the plume structure and its width. Firstly, a grid study was performed to find out the best grid size for this purpose. Then calculations were done which showed a very good agreement with earlier reported experimental based correlations for the temperature of the plume region. These studies have been extended to use this field-model based tools for modelling particular separate effect phenomena like puffing frequency and to validate against experimental data. There are several applications in nuclear industry like room fires, wildland fires, smoke or ash disposal, hydrogen transport in nuclear reactor containment, natural convection in building flows etc. In this paper the use of FDS with the advanced Large Eddy Simulation (LES) based CFD turbulence model is described for various applications: Fire simulation for Alpha storage, Bhabhatran teletherapy, pool fire for transport casks, fire PSA of a representative NPP, exhaust air fan buildings of a process plant and smoke dispersion in large fires around NPPs.