Fire Safety Engineering Research Articles

Defining a maximum heat release rate probability distribution function for design fires in sprinkler‐protected residential buildings

AbstractIn fire safety engineering analysis of sprinkler‐protected residential buildings, the maximum heat release rate is a key parameter requiring consideration. Several documents provide advice for estimating the heat release rate of a sprinkler‐controlled fire, with a prevailing suggestion that it is fixed upon activation of the first sprinkler. When carrying out deterministic analysis, this requires the engineer to assume fixed fire parameters and consider that sprinklers limit fire growth. To explore these assumptions, the study uses three deterministic models to estimate a sprinkler‐controlled maximum heat release rate for a representative apartment layout. The models include Alpert's correlation, a B‐RISK zone model and a computational fluid dynamics model in the Fire Dynamics Simulator. These deterministic models are compared to a probabilistic model in B‐RISK, where Monte Carlo simulations are used to generate a range of maximum heat release rates from distribution functions for fire and sprinkler properties. An output distribution function is generated with a mean of 296.6 kW and a standard deviation of 503.8 kW, with a lognormal distribution (μ = 5.014, σ = 1.165) estimated as a best‐fit. The deterministic models are estimated to sit in the 92–98 percentile range of this function, indicating that common deterministic assumptions are reasonably conservative. The article concludes with suggesting that, for deterministic analysis, a percentile between the 80th and 99th (340–2640 kW) could be qualitatively selected based on the design objectives, building situation and relative consequence of a fire. Further research is needed to establish guidelines for selecting appropriate percentiles across various building scenarios.

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.

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.

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.

A new fire damage index to assess the vulnerability of immovable cultural heritage

The recurrent occurrence of devastating fires in cultural heritage constructions highlights the need for more studies focusing on the assessment of their fire vulnerability to support the development of adequate mitigation measures. To address the limitations of existing methods, this article introduces the Potential Fire Damage Index (PFDI) as a new approach. The PFDI is an indicator-based method that integrates twenty-one Fire Vulnerability Indicators (FVIs) into four categories with varying weights. The method is applicable to various types of heritage constructions and independent of national fire safety codes, which makes it a versatile tool for assessing fire vulnerability and estimating potential damage that can impact the cultural values of these structures. The article emphasizes the significance of the PFDI for preliminary identification of critical points in heritage constructions requiring vulnerability reduction measures, paving the way for subsequent more rigorous fire safety engineering analyses. The detailed criteria for assessing the FVIs are presented, and a case study illustrates the PFDI's applicability. The case study analyses a historic church in Portugal and evaluates its current conditions, as well as the impact of implementing certain measures to reduce fire vulnerability. To evaluate the robustness of the PFDI, its results were also compared with those of a well-established method in the literature.

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.

Decision-making in balancing fire safety hazards against security threats within the built environment

The built environment faces challenges from fire hazards and threats by malicious actors. Risks presented from these hazards and threats are managed through the practices of fire safety and physical security. Whilst distinct disciplines, both impact the built environment systems, resulting in potential conflict. To manage this conflict, a complex process is required. Through the framework of Governmentality, using a mixed methods approach, the study explored the process which fire safety engineers and security practitioners undertake to manage this conflict. The study produced a conceptual model that explains how practitioners operate and manage risk associated with fire safety hazards and security threats. The model indicates that the process for resolving conflicts is a dichotomy between physical security and fire safety, with fire safety being the most dominate and influential. Nevertheless, both fire safety and physical security are subservient to building regulations in this process; however unlike security, fire safety is codified through building regulations. Risk assessment and the design process are core processes, but only used in decision-making when there is conflict between the fire safety and physical security. Findings demonstrated that context remains static for greater threats, whereas context is dynamic for fire safety.

Evaluating 900 Potentially Harming Fires in Germany: Is the Prescriptive Building Code Effective? German Fire Departments Assessed Fire Safety Measures in Buildings Through On-Site Inspections

Fire statistics mirror the outcome of fire prevention. Most fire statistics in Germany deal with the loss of life, value, and fire department actions (number of interventions, nozzles used, or alarm category like a false alarm). However, these results also represent the safety level the legislator has set through the prescriptive building regulations. The current statistics cannot evaluate the level of fire safety and the fulfillment or necessity of fire safety precautions. Today, expert judgment from firefighters is necessary to fill this gap. Here, we show the first evaluation of fire prevention and hazard protection measures by evaluating 900 potentially harming fires throughout Germany. In contrast to minor fires, these fires have advanced to the extent that they could potentially violate the protection objectives outlined in building regulations. The fire department association developed a questionnaire to evaluate the fire safety level and possibly reduce unnecessary fire safety regulations. One hundred twenty-three fire departments carried out the questionnaire, which are responsible for 25% of the German population. Fire prevention officers of the fire departments went to the scene after the fire was extinguished, and the fire safety concept of the building could be evaluated. We found a high rate of injuries, smoke spread, need for rescue by firefighters, and higher than expected firefighter response times after arrival at the scene. Surprisingly, smoke spread rates correlated with building height and not with building age. It was even possible to assess the risk of multiple casualties. Overall, the questionnaire results give insight into the current level of fire safety in existing buildings. Ways and rates for smoke and fire spread prove the importance of second escape routes and the influence of human misconduct. According to these results, current building code regulations are sufficient to prevent fire spread. On the other hand, smoke spreading is a severe threat to people’s safety. For example, the data shown can be applied in Bayes nets or other risk calculations to optimize individual building designs or even governmental building codes concerning fire safety engineering. Based on our observations, science, and building codes, authorities could in the future establish a performance-based building code instead of the current prescriptive code. This paper presents the first approach in Germany to quantify the expert judgment of fire departments and use it as a source of knowledge for fire prevention.

A multiscale model for wood combustion

AbstractUnderstanding wood combustion has become increasingly critical as fire safety engineering moves toward a performance‐based approach to building design. Although different kinetic models have been developed for wood burning, chemical kinetics remains a significant challenge for accurate prediction. This work has developed a novel multiscale model by implementing kinetic parameters calculated from molecular dynamics simulations using reactive forcefield into a kinetic model of wood burning. The calculated kinetic parameters of the main components in wood, namely, cellulose, hemicellulose, and lignin, are first utilized to model microscale thermogravimetric experiments for validation. Subsequently, the mesoscale and full‐scale fire tests have been simulated by the multiscale model. Furthermore, the fire properties of various wood species at different heat fluxes have been predicted and compared with results from the cone calorimeter test. Our multiscale model outperforms existing kinetic models in predicting wood combustion and can effectively discern the influence of chemical components on fire properties.

Влияние длительного естественного старения теплоизоляционных минераловатных материалов на физико-химические и термические превращения

Purpose. The article studies physico-chemical and thermal transformations of mineral wool thermal insulation of natural ageing. The subject of the study is thermal insulation materials of natural ageing, and the object of the study is their physicochemical and thermal characteristics. The aim of the work is to establish physicochemical and thermal transformations of mineral thermal insulation of natural ageing. The research is aimed at identifying features of physico-chemical and thermal transformations of thermal insulation based on mineral fibers and organic binders in the ageing process. Methods. A set of precision physicochemical methods such as X-ray phase analysis (XRF), infrared spectroscopy and thermal analysis methods (TG, DTG, DSC) was used. Findings. The results of studying mineral thermal insulation (service life of 60 years) revealed characteristic changes in the structure of the material. The XRF method established that the ageing process of mineral wool materials is caused by occurring microdefects and disruption of material fibers structure organization. Changes in thermal insulation phase state have thermal fluctuation of kinetic nature of material mechanical destruction. The IR spectroscopy method identified changes in the areas of characteristic absorption bands: 2 800–2 200, 2 000–1 600 and 1 295–1 005 cm–1 caused by chemical destruction of organic binder in mineral thermal insulation. The nature of thermal transformations of the material was established, a tendency towards a decrease in the threshold temperatures for mass loss start due to destructing polymer binder was revealed. It is noted that natural ageing may result in loss of fire resistance of thermal insulation systems, as well as in intensificating smoldering combustion of thermal insulation. Research application field. The results are of interest to builders, designers, fire safety engineers and can be used in regulatory and technical as well as in reference literature on fire safety. Conclusions. During the ageing process irreversible physical and chemical changes occur in the structure of thermal insulation, leading to loss of thermal stability of the material and to a possible increase in the intensity of latent smoldering combustion. Technical obsolescence of the material leads to decreasing fire resistance limits of various thermal insulation systems due to loss of thermal insulation capacity and integrity.

Contemporary Fire Safety Engineering in Timber Structures: Challenges and Solutions

As environmental conservation and sustainability gain prominence globally, modern timber structures are receiving increased focus. Nonetheless, the combustible nature of timber raises significant fire safety concerns. This review explores the recent advancements in fire safety engineering for timber structures, emphasizing both contemporary high-rise buildings and historical timber constructions. It covers topics like inherently safer design principles, fire risk prediction, and evacuation methodologies. The review emphasizes the criticality of selecting suitable materials, structural design, firefighting systems, and advanced sensor technologies for early fire detection. Additionally, we analyze and compares various evacuation strategies, offering insights into the challenges and future directions for fire safety in modern timber structures.

Determinants of stair climbing speeds in volunteer firefighters

Stair climb is a physically demanding task for firefighters and plays an important role in firefighting. Yet little is known about factors affecting the speed of firefighters on stairs. The aims of this study were to quantify stair climbing speeds in firefighting and to establish the relationship between multiple factors and stair performance of firefighters. A convenience sample of sixty-three volunteer firefighters (30.4 ± 8.2 years; BMI 26.2 ± 4.2 Kg/m2) performed stair climb exercises under different conditions: without additional equipment, with Personal Protective Equipment (PPE), with PPE and Self-Contained Breathing Apparatus (SCBA), and with PPE and SCBA while carrying a tool (e.g., axe, hose, Halligan, etc.). The observed climbing rates of the SCBA and Tool conditions align with earlier studies. Multiple Linear Regression (MLR) analysis revealed that the combination of extrinsic factors (covered distance and equipment weight) along with intrinsic factors (gender, age, Body Mass Index and handrail use) significantly explained 37 % of the variance in ascent speed and 23 % of the variance in descent speed of firefighters. Overall males exhibited faster speeds and older age, higher BMI, and longer distances lead to slower speeds. Equipment weight was found to be the most substantial individual predictor on stair performance in firefighters. For example, carrying an extra load equivalent to 30 % of body mass resulted in a decrease of 24.8 % and 17.6 % in ascent and descent speed respectively. These findings may contribute to improve fire safety engineering analysis and firefighting operations.

REVIEW OF FIRE BRIGADE EXTINGUISHMENT MODELS AS PART OF A BUILDING FIRE RISK ASSESSMENT

This paper presents models of firefighting operations of fire brigades from the point of view ofassessing the fire risk of buildings. The following seven related standards can be distinguishedworldwide: International Fire Code (IFC), NFPA 5000: Building construction and safety code,International Fire Engineering Guidelines (IFEG), Fire Risk Evaluation and Cost AssessmentModel (FireCAM), Fire Evaluation and Risk Assessment system (FIERA), PD 7974-5:2014Application of Fire Safety Engineering Principles to the Design of Building; Part 5 Fire and RescueService Intervention as well as a Fire Brigade Intervention Model (FBIM). Given the editoriallimitation as to the amount of text only the last one of them, which was used to the greatestextent in the construction of own model, was discussed in detail. The others have been discussedonly in a general way. In the final part of the work, the existing models were evaluated as partof the discussion. On the basis of a critical review of literature and own research of the authors,a stochastic model of firefighting activities of fire brigades in Poland was developed, which will beone of vital elements of the Aamks software developed at the Fire Safety University for assessingthe fire risk of buildings. The description of this model along with the results of its operation andtheir discussion will be presented in the successive parts of the same series.

A SaaS Concept-Based Shopping Center Fire Risk Assessment Model for the Safety Management Applications

This paper proposes a solution to the problem of software absence for the quantitative fire safety analysis of complex objects, which is suitable not only for highly qualified scientists and experts but also for fire safety engineers and inspectors and is compatible with mobile devices. Existing software solutions for quantitative fire safety analysis are desktop-based, and all require a high level of competence of users. We propose a solution by combining the formalism of typical probabilistic structural–logical (TPSL) models, the Software-as-a-Service (SaaS) concept, and end-to-end encryption. Using TPSL models allows the development of cloud-based applications with a simple request-based application programming interface and intuitively understandable user interface to assess the level of safety of complex objects. As a result, we could use such mobile device-ready applications both for developing mobile device applications and developing mobile-device-friendly website-based services to carry out safety control inspections or level of safety management.

Introduction to grid‐scale battery energy storage system concepts and fire hazards

AbstractAs the world continues to enact progressive climate change targets, renewable energy solutions are needed to achieve these goals. One such solution is large‐scale lithium‐ion battery (LIB) energy storage systems which are at the forefront in ensuring that solar‐ and wind‐generated power is delivered when the grids need it most. However, the perceived hazards of LIBs due to recent events in the United States and Australia pose a risk to their future success. When a battery energy storage system (BESS) has a multilayered approach to safety, the thermal runaway, fire, and explosion hazards can be mitigated. Successful implementation of this approach requires cooperation, collaboration, and education across all stakeholder groups to break down these preconceived notions. Much can be learned from the recent BESS fire and explosion events to inform safer design and operation. These events and their contributing factors share many commonalities with historic losses in the hydrocarbon industry. Fire and process safety engineers who have traditionally worked in the hydrocarbon industry can be of immense value to the BESS industry.

Cost-benefit analysis in fire safety engineering: State-of-the-art and reference methodology

Cost-effectiveness is a key consideration within fire safety engineering. Currently, different approaches are being applied in literature. These approaches differ in how cost-effectiveness is evaluated, which costs are considered, and how the preferred design solution is defined. Recognizing this issue, the Fire Protection Research Foundation enrolled an international team of researchers, supported by a broad stakeholder panel, to develop a reference methodology. In this paper, this reference methodology for cost-benefit analysis in fire safety engineering is presented following an extensive literature review. The methodology clarifies the minimum requirements for assessing cost-effectiveness, and highlights that only a present net value evaluation can be used to compare design alternatives. Commonly used cost-benefit ratios should only be used when deciding on the effectiveness of a single package of fire safety measures. An illustrative case study demonstrates the application of the methodology and shows how designs based on cost-benefit ratios can be sub-optimal when evaluating multiple possible fire safety measures.

Revisiting the “Steiner Tunnel” test method covered under ASTM E84: An overview and analysis of the test method

The “Steiner Tunnel” test, which is standardized under ASTM E84 and UL 723, is used to comparatively assess surface-burning characteristics, namely, flame spread and smoke release from a wide range of building materials and assemblies. While the method is well known to fire safety engineers, it is not as well understood by material scientists who develop new fire safe materials that will meet this test. Understanding how the test measures flammability and smoke is critical to designing materials that can meet requirements that reference E84 and UL 723. This article primarily discusses the ASTM E84 test, discusses the history of the method, how it measures flame spread and smoke release, and how mounting samples in the test method affects flame spread and smoke release. Finally, there is discussion on test methods that could be used for qualitative screening tools for materials developed for the E84 test.