Fire Engineering Research Articles

Experimental study on fireproof of aviation lubrication oil tank

Abstract This paper presents an experimental study on the fireproof performance of aeroengine lubrication oil tanks. By constructing a simplified lubrication oil tank model and simulating the harsh operating conditions of engine fires, the oil tank was exposed to flames generated by a standard burner for testing. The study monitored and recorded key parameters such as temperature, pressure, flow rate, and phase changes within the tank. The results indicate significant differences in the temperature distribution characteristics of the tank walls under different inlet temperatures and flow conditions. In the rigorous 15-minute flame test, all tests successfully completed the fire verification process.

Case study on thermal and flow analysis of a water mist on a pool fire in a ventilated engine compartment

Public transport buses and other large vehicles are facing increasing engine fire issues stemming from higher operating temperatures, phonic insulation and low maintenance time. The fire suppression systems currently employed or considered for vehicles could be used for the protection of buses. Water mist is one of these technologies. One of the challenges a water mist faces for the fire protection of small enclosures is the ventilation. Inside a full scale engine compartment of a truck, the interaction and heat transfer between a n-heptane pool fire and water mist droplets are studied using velocimetry techniques. Most notably, the influence of the nozzle operating pressure and a variable cross-flow ventilation on the extinguishing performance is explored. In this preliminary study without clutter, the results show the importance of the ventilation flow on the performance of the water mist. Moderate ventilation speeds up to 3.2ms-1 show an improvement of the extinguishing time over natural ventilation while a higher ventilation speed of 6.4ms-1 degrades the extinguishing performance of the mist. For low-pressure water mists, the momentum of the spray is the most important factor for water mist extinguishing performance.

CFD-based analysis of deviations between thermocouple measurements and local gas temperatures during the cooling phase of compartment fires

Data from thermocouple (TC) measurements play a pivotal role in fire safety science and engineering studies. It is well-known that there are deviations from the actual local gas temperature and many studies have led to the development of correction factors. The present study focuses on these deviations inside compartments through a systematic series of CFD simulations, performed with Fire Dynamics Simulator (FDS), version 6.8.0. A canonical cubic box is used as geometry. This allows for the demonstration of the impact of the presence of smoke, with variable optical thickness, on the TC data as retrieved from FDS. Significant differences are observed between TC measurements and local gas temperatures. Corrections as developed for TC measurements in open atmospheres cannot be readily applied in compartment configurations, where smoke properties change both spatially and temporally.

Flexible and Flame Retardant Cotton Fiber-reinforced CS/CNF/EP Composites For a Sensitive Fire Warning

Enhancing fire safety performance in resin-based composites is critical for mitigating fire hazards. Composites that provide early warnings during initial fire stages and maintain prolonged alarm capabilities under flame exposure are essential for minimizing injuries and property damage. This study employs chitosan (CS) as a cross-linking and char-forming agent, while carbon nanofiber (CNF) acts as a flame retardant and conductive component. Cotton fiber-reinforced chitosan/carbon nanofiber composites with varying epoxy and CNF contents (CS/CNF/EP) were prepared through a straightforward low-temperature curing process (40 °C, 4 h). Crosslinking polymerization between chitosan and epoxy was confirmed via Fourier Transform Infrared Spectroscopy (FTIR). The presence of the tough structure of CS and the rigid structure of EP results in a synergistic toughening and reinforcement effect in the CS/CNF/EP composites. Additionally, due to the carbon facilitating properties of CS and the enhanced conductivity of CNF, the composites exhibit a sensitive fire alarm functionality. At 35 % epoxy content, the CS/CNF/EP composites demonstrated exceptional properties, including mechanical flexibility (tensile strength of 7.09 MPa and breaking elongation of 129.05 %) and outstanding flame retardancy (LOI of 32.3 % and UL-94 V-0 rating). These composites provided a rapid alarm (∼1 s), sustaining a 263 s warning under flame exposure and over 35 min post-flame removal. These findings indicate that CS/CNF/EP composites, integrating mechanical flexibility, flame retardancy, and superior fire warning properties, present significant potential applications in fire safety engineering.

Reliability-based safety format for structural fire engineering – Derivation based on the most likely failure point

Designing structures for burnout resistance ensures stability during evacuation and search and rescue operations, limits collateral damage, and enhances post-fire repairability. This represents a significant shift from traditional prescriptive designs that do not evaluate performance under realistic fire conditions. However, given the variability in fire exposure and structural response, it is unclear which input values should be used to ensure a high level of reliability for burnout calculations. This paper introduces a safety format for burnout resistance compatible with the Eurocode and its reliability principles. The format allows users to specify desired reliability levels and prescribes equations for determining design values for load effects and fire load density using predetermined sensitivity weights. A method for calculating default sensitivity weights is outlined, proposing tentative values: 0.65 for resistance effect, -0.40 for load effect, and -0.80 for fire load density, with a default coefficient of variation of 0.30 for resistance effect when case-specific information is lacking. The safety format's performance is verified through case studies of a concrete slab and a numerical evaluation of a steel column, showing satisfactory and conservatively assessed results. Inherent conservatism in the design format may, however, occasionally lead to the undue rejection of designs. Further investigations are necessary to confirm the safety format's conceptualization, default sensitivity weights, and the influence of the adopted compartment fire model.

Experimental study on the burning rate and flame dynamics of oil reservoir pool fire under cross-wind: Effect of lip height

The study of combustion characteristics and heat feedback mechanisms of liquid fuels is important for fire safety engineering, particularly in the context of energy utilization. In thiswork, the effect of lip height on the evolution of n-heptane pool fire burning rates and flame heights, as well as the thermal feedback control mechanism, were investigated in a series of experiments in the presence of cross-wind. The results showed that the lip height of pool and cross-wind speed have a significant effect on the flame characteristics and heat feedback mechanism. For a given wind speed condition, the radiative feedback fraction and the convective feedback fraction showed non-monotonic changes with an increase in the lip height of pool. With the increase of lip height and cross-wind speed, the lift off phenomenon gradually appeared inside the oil pool, while the flame height outside the oil pool gradually decreased. A new correlation is proposed, which can well describle the relationship between the flame height and the ratio of the air entrainment caused by the cross airflow to that caused by the flame buoyancy, which can provide references for the utilization and management of energy storage strategies nowadays.

The methodology for evaluating the fire resistance performance of concrete-filled steel tube columns by integrating conditional tabular generative adversarial networks and random oversampling

Artificial Intelligence (AI) technology has emerged as a powerful tool for addressing various complex issues within engineering structures. Accurately assessing the fire resistance performance of Concrete-Filled Steel Tube (CFST) columns poses a significant challenge for researchers. The scarcity of CFST column fire resistance test data presents a hurdle in the development of Machine Learning (ML) models. To tackle this issue, this study proposes a novel ML approach that integrates Conditional Tabular Generative Adversarial Networks (CTGAN) and Random Oversampling (ROS) for evaluating CFST column fire resistance performance. CTGAN technology is used to generate synthetic datasets to alleviate data scarcity issues, while ROS technique is used to balance the dataset. To validate the effectiveness of this method, detailed experimental tests using eight ML algorithms were conducted on both real and synthetic datasets, with results indicating superior performance on the synthetic dataset compared to the real dataset. The optimal model in the synthetic dataset achieves an Accuracy, Precision, Recall, and F1-Score of 0.972, 0.973, 0.972, and 0.972, respectively. Furthermore, extensive comparative analyses and practical applications of the proposed method were conducted, revealing its exceptional performance in evaluating the fire resistance of CFST columns. To facilitate ease of use and operation in practical engineering, a visual interface was developed. The introduction of this technique offers a novel solution for researchers and engineers in the field of structural fire engineering.

Numerical Design Calculation of T-stubs at Elevated Temperatures

AbstractThe failure of steel connections can lead to the progressive collapse of the entire structure. Accurate modelling of steel connections at elevated temperature allows structural fire engineers to design steel structures that may deal with the severity of a fire. The prEN 1993-1-14 proposes numerical design calculation for the static design check of steel connections. This paper presents a component-based finite element model (CBFEM) to design the T-stubs at elevated temperatures. The generated model is verified and validated against the results from the analytical model and experimental study. The resistance, failure modes and the load-deformation curves are used to validate and verify the CBFEM models for steel connection design at elevated temperatures. The results stated that the CBFEM is a practical design tool to model bolted connections at elevated temperatures and it is possible to apply the recommended 5% plastic limit strain by EN 1993-1-5 for fire design of bolted connections.

A fire safety engineering approach to improving community resilience to the impacts of wildfire

AbstractEach year severe wildfires continue to cause significant destruction resulting in the loss of life, property, critical infrastructure, and the environment. In an effort to increase community preparedness and resilience to wildfire, international jurisdictions have adopted both guiding principles and prescriptive codes that apply to both urban planning and fire engineering design of buildings within the wildland–urban interface. These measures are intended to protect occupants, enhance the survivability of structures from different fire exposure mechanisms, and increase the chances of successful firefighting operations. However, research has identified (i) inconsistent approaches to regulation and governance; (ii) limited research on which urban design and building standards are based; and (iii) misaligned or contradictory urban design and building standards. This not only stifles the use of development proposing suitable performance‐based design that could achieve the required outcomes but can increase administrative burdens and development costs without increasing safety. The aim of this current study is to contribute to addressing identified shortfalls by identifying and distilling the last 23 years of research in the field related to (i) the development of evidence‐based performance requirements, and (ii) the application of effective governance arrangements in order to enhance urban design and wildfire engineering practices. These aims are achieved through a systematic literature review. Ultimately, however, of the 608 initial articles captured in the identification phase of the SLR, not a single article provided insight into the most effective regulatory or governance mechanism, and only three provided criteria suitable for adoption as a performance requirement. While the aims of this study were only partially achieved, it does provide a foundation for the field by way of identifying and distilling the current state of practice.

Assuring fire safety in nuclear plants with international standards

This paper presents the evolution and benefits of international standards for fire safety engineering11Fire safety engineering and performance-based fire safety are both widely used, and both represent an engineering process to determine performance of a fire protection plan based on the results of fire calculations. developed at the International Organization of Standardization (ISO). The history of fire safety in nuclear power plants along with the need for fire safety regulation is discussed to lay the foundation for the standards development work. The evolution of fire safety regulation from prescriptive to performance-based is also presented as the background for the research.Extensive research of the issues that arise for performance-based fire safety regulation, specifically for computer models for fire safety calculations, which included international benchmark exercises formed the basis to identify the need for developing international standards for fire safety engineering. The research focused both on the verification and validation (V&V) of computer fire models and determining their predictive capability. The paper for the first time takes new scientific and engineering data from benchmark exercises to assess the suitability and applicability of computer fire models for application in nuclear power plants. The paper reports on the findings of the benchmark exercises and their use in formulating new requirements in ISO international standards on verification and validation of fire calculation methods and the fire safety engineering process through a consensus process of international experts.Discussion of the foundational research at the ISO fire safety engineering committee (ISO TC 92 SC 4) led to a consensus to revise two international standards. One specifying the principles and general requirements for fire safety engineering, and another on the verification and validation procedures for fire calculation methods. The development and content of these two international standards are discussed in this paper. An international technical report was subsequently developed at the ISO committee for conformity assessment (CASCO) to provide guidance for the certification of the fire safety engineering process, and specific parts of it, namely the V&V of fire calculation methods.It is concluded that the fire safety engineering international standards presented in this paper can support rigorous performance-based fire safety regulation for nuclear power plants. These ISO international standards will be particularly useful to nations that have not yet developed the regulatory infrastructure for nuclear power regulation. The international standards are also available to those that would like to transition to the use of international standards and an ISO standards-based certification scheme. Regulations based on these international standards will provide citizens with confidence in nuclear power as a viable option to address climate change.

Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels

This investigation is propelled by engineering challenges associated with heat transfer during fire incidents on inclined surfaces, such as those observed in pitched roof fires, which hold significant implications for fire safety engineering and energy conservation. Drawing inspiration from real-world fire dynamics, this study delves into the downward flame spread over inverted solid fuel surfaces across a range of inclination angles, bridging the gap between theory and practice. Detailed analysis of temperature distribution, flame characteristics, and gas-phase reactions reveals critical insights into the complex interplay governing heat behavior under these conditions. The observed reduction in flame thickness and standoff distance with increasing inclination underscores the influence of buoyancy-induced plumes. This work developed a dimensionless formula that accounts for both buoyancy-induced plumes and diffusion rates perpendicular to the fuel, successfully capturing the variation in flame thickness with inclination angles. Furthermore, our findings show that the average flame spread rate escalates with higher inclination angles, attributed to enhanced gas-phase reactions near the flame front that lead to intensified heat transfer and a subsequent increase in temperature within the solid phase. The study also uncovers a competitive mechanism between flame “jumps” and heat transfer to the unburned zone, causing an initial increase and then a decrease in flame spread rates with increasing discrete gap size at larger inclination angles. Conversely, at smaller inclination angles, flame progression halts as the discrete gap size increases, due to inadequate heat transfer to the adjacent discrete fuel, resulting in the cessation of flame spread. This study not only advances our understanding of the thermal processes underpinning flame spread in inclined configurations but also offers crucial insights for developing more effective fire protection strategies and thermal protection systems in engineering applications.

Scaled experiment and numerical study on the effect of a novel makeup air system on smoke control in atrium fires

In the field of fire safety engineering, makeup air systems design for atriums is always a concern for researchers and engineers. A novel makeup air system integrating breathing zone and underfloor air supply (BUMS) was applied in the investigated atrium in this study. However, the flow rates proportional relationship of makeup air required for effective smoke control on each floor remains unclear. Scaled experiments and numerical simulations were carried out to address this problem in this study. The results show that the BUMS effectively controlled temperature, followed by visibility, with minimal impact on carbon monoxide (CO) concentrations. When the flow rate of makeup air was equal on each floor, the sizes of the safe evacuation passageways created by the BUMS on the third and fourth floors were not conducive to the safe evacuation of personnel. Based on the proportion of the CO concentration of each floor under natural ventilation, distribution proportions of makeup air flow rate were obtained. The effective action area was used to help determine the upper limit flow rate ratio for each floor. Calculation results revealed that when the flow rate distribution proportion for the first to fourth floors was 15 %, 27 %, 28 % and 30 %, respectively, the smoke control effectiveness has been improved. These findings are expected are expected to provide a theoretical basis for designing makeup air systems in atrium and large-space buildings.

Optimal distribution of emergency resources to accidents for pre-rescue in chemical industrial parks

Medical and fire resources are scheduled to chemical industrial parks which have caused mass casualties due to accidents. However, most of models of emergency logistics do not account for pre-rescue before large-scale rescue which may increase the casualty rate because of the long emergency response time and distance. This paper presents a mathematical model proposed for optimal distribution of emergency resources for rescuing the trapped victims who are highly likely to be seriously injured or even killed before the arrival of ambulances and fire engines. Due to the different types and risks of accidents at various locations have different impacts on people, we consider the detailed characteristics of accident scenarios and maximum tolerance time for the trapped victims to determine the priority of rescue sites. In addition, this paper proposes two indices of pavement resistance coefficient and obstacle to reflect the environment after accidents, which are not involved in other models of emergency resources distribution. Based on these, a penalty cost objective function is established to maximize the rescue rate. The optimal delivery route which reflects the distribution process is planned for the robot that will save more casualties. Two simulations and a real accident case study were conducted by minimizing the objective function, and the numerical results showed the reliability and effectiveness of the presented model for making optimal decisions for emergency distribution to accidents in chemical industrial parks.

Testing and evaluation of light clothing properties used in fire and rescue service units

In the testing room for examination products of the Fire Engineering and Expert Institute (FEEI) of the Ministry of the Interior of the Slovak Republic in Bratislava, the Slovak National Accreditation Service SNAS has granted accreditation. Accredited testing room with identification number no. S-084 performs tests applied in the field of personal protective equipment. The goal is to specify, determine, and, above all, verify the selected characteristics for emergency clothing (light emergency clothing - LEC) used by firefighters and rescuers in the Fire and Rescue Service units to determine the conditions for procurement and quality control of the LEC supplied. The results obtained during the examination of the properties of light emergency clothing will be used in the next steps of the research of the Product Assessment Department (PAD) FEEI of the Ministry of the Interior of the Slovak Republic. In contrast, individual parameters can be used to design new LEC. The basic meaning and purpose of any protective means are to protect a person who intervenes in a dangerous environment contaminated with chemical, biological or radioactive substances, for example, in industrial accidents connected with the release of dangerous substances (HAZMAT), in accidents of vehicles transporting HAZMAT and natural disasters or fires of various nature. Protecting from the external environment is one of the favourable inherent properties of personal protective work equipment (PPE).

Predicting the Average Charring Rate of Mass Timber Using Data-Driven Methods for Structural Calculations

AbstractEngineered timber is increasingly in demand for tall buildings due to its positive impact on building sustainability. However, quick adoption raises fire engineering questions regarding flammability and structural performance. Understanding the behaviour of timber in fire is crucial, particularly for structural calculations of tall buildings. The charring rate of timber plays a significant role in its structural performance because the loss of cross section reduces the load bearing capacity of the element. Eurocode-5 (EC5) provides a simple method to calculate the charring rate and it is widely adopted for design in many countries while more complex physics-based models exist but are rarely used for design. For example, we want to know when EC5 underpredicts or overpredicts and by how much. This paper compares different data-driven methods, including statistical and artificial intelligence algorithms, for predicting the average charring rate of timber in fire. A new database of charring rates, VAQT, was created comprised of 231 furnace tests of timber products found in the scientific and technical literature. Statistical methods such as ridge regression (λ = 0.001) predict the charring rate with a minimum 11% error whilst EC5 predicts with 27% error. A trained neural network predicts the charring rate with minimum 9% error. This paper presents a novel database of timber charring experiments and provides a set of data-driven predictive models, all of which calculate the average charring rate with a significantly higher accuracy than EC5 for a wide range of mass timber products.

Gasoline Engine Misfire Fault Diagnosis Method Based on Improved YOLOv8

In order to realize the online diagnosis and prediction of gasoline engine fire faults, this paper proposes an improved misfire fault detection algorithm model based on YOLOv8 for sound signals of gasoline engines. The improvement involves substituting a C2f module in the YOLOv8 backbone network by a BiFormer attention module and another C2f module substituted by a CBAM module that combines channel and spatial attention mechanisms which enhance the neural network’s capacity to extract the complex features. The normal and misfire sound signals of a gasoline engine are processed by wavelet transformation and converted to time–frequency images for the training, verification, and testing of convolutional neural network. The experimental results show that the precision of the improved YOLOv8 algorithm model is 99.71% for gasoline engine fire fault tests, which is 2 percentage points higher than for the YOLOv8 network model. The diagnosis time of each sound is less than 100 ms, making it suitable for developing IoT devices for gasoline engine misfire fault diagnosis and driverless vehicles.

Examining Parking Management Methods in Alleyways Through Fire Engine Dispatch Experiments

Rapid response is essential to reduce damage to life and property from fires. However, fire engines are being delayed due to vehicles parked in alleyways. To solve this problem, compulsory disposition has been legislated; however, there are few cases of its use. Therefore, based on advice from experts and firefighters, we conducted 17 experiments of four types and summarized the results. Experimental results: First, The minimum alleyway width required for emergency fire engine dispatch is 3.5 meters. Second, one-sided parking in a line can minimize fire engine dispatch delays. Third, when parking in a zigzag pattern on both sides, the parking gap should be at least 10 meters. Fourth, parking should be prohibited for at least 10 meters from the curved point of the alleyway. Fifth, when a compulsory disposition is performed, the direction of the front wheels of the parked vehicle must be checked. The study results can be adopted to manage the method of parking in alleyways and minimize fire engine dispatch delays.

Common incidents and prevention of urban water supply pipeline accidents

With rapid urbanization, urban water supply pipeline accidents have become increasingly prevalent. Understanding their common occurrences and prevention strategies is crucial for ensuring water safety. This study aims to explore the underlying causes of such incidents, ranging from ageing infrastructure to design flaws and construction issues. By analyzing existing preventive measures and international best practices, this research seeks to contribute to the development of effective strategies for mitigating urban water supply pipeline accidents. This thesis focuses on urban water supply pipeline accidents, addressing both common incidents and preventive measures. It begins by highlighting the unique challenges of fires in high-rise buildings, including their rapid spread and the difficulties in evacuating occupants. The paper then emphasizes the importance of innovative fire-resistant materials, classifying them into various types such as phenolic, sprayed, calcium silicate, and lightweight composite materials. Each type is explored in detail, discussing their properties and potential applications. Finally, the paper outlines the practical use of these materials in fire engineering, emphasizing their role in enhancing the safety and resilience of urban infrastructure. Overall, this thesis contributes valuable insights to understanding and mitigating the risks associated with urban water supply pipeline accidents, promoting disaster prevention and management efforts.

Numerical design calculation of bolted lap joints at elevated temperatures

This paper presents experimental and numerical studies to investigate the mechanical behaviour of bolted lap joints at elevated temperatures. The load-deformation curves, failure modes, and resistance values of the specimens were obtained from experimental studies. A solid finite element model generated using ABAQUS software was validated and verified by the experimental results and analytical models to investigate the different failure modes and predict the fire resistance of bolted lap joints at elevated temperatures, respectively. Then, the component-based finite element model (CBFEM) was prepared to analyse the fire behaviour of bolted lap joints as an alternative to design specifications for structural fire engineers. The CBFEM was verified by the validated solid model and analytical models in terms of load-deformation curve, fire resistance, and failure modes. Parametric studies were performed to investigate the influence of several parameters on the fire response of bolted lap joints. The study shows that the CBFEM may be used to design bolted lap joints at elevated temperatures and the 5 % limit strain for plates proposed in EN 1993-1-5 can be applicable for predicting the fire resistance of steel connections.

The role of large language models (AI chatbots) in fire engineering: An examination of technical questions against domain knowledge

This communication presents a short review of chatbot technology and preliminary findings from comparing two recent chatbots, OpenAI’s ChatGPT and Google’s Bard, in the context of fire engineering by evaluating their responses in handling fire safety-related queries. A diverse range of fire engineering questions and scenarios were created and examined, including structural fire design, fire prevention strategies, evacuation, building code compliance, and fire suppression systems. The results reveal some key differences in the performance of the chatbots, with ChatGPT demonstrating a relatively superior performance of 88% (vs. 80% for Bard). Then, this communication highlights the potential for chatbot technology to revolutionize fire engineering practices by providing instant access to critical information while outlining areas for further improvement and research. Evidently, and when it matures, this technology will likely be elemental to our engineers’ practice and education.