Fire Safety Engineering Research Articles

Influence of wind on the onset of flashover within small-scale compartments with thermally-thin and thermally-thick boundaries

Thermally-thin compartment fire studies are a reasonable approach to understand fire dynamics in informal settlements, where dwellings built with such materials (e.g. steel sheets) are commonly found. Since the number of people living in informal settlements is growing (currently over 1 billion), fire safety engineering research is of major importance for reducing fire occurrence, loss of life, livelihood, and property. This work studied numerically a set of thermally-thin and thermally-thick walled small-scale (1/4 scaled ISO-9705 room) compartment fires in a wind tunnel. This work aims to understand the effect of wind on the heat release rate necessary to reach the onset of flashover (HRRfo) inside the compartment by varying the wind velocity and direction (on the side or back wall). It was found that HRRfo increased with wind velocity for both wind directions for thermally-thin boundaries, while HRRfo decreased with wind velocity for thermally-thick boundaries. It was also found that the wind effect was more significant when blowing on the side wall. It was shown that those results were caused by heat transfer losses through walls and by wind-induced pressures at the doorway; the former being the driving mechanism for thermally-thin walled compartments and the later for thermally-thick bounded compartments.

A new test method to determine the fire behavior of façades with etic system

SummaryNew building high‐energy efficiency requirements have introduced a significant utilization of combustible materials as thermal insulation in building envelopes and especially in façades. The damage occurring in case of fire can thus become considerable, due to greater fire spread. Risks for building occupants and unsafety for rescue team are added to social, economic, and environmental consequences. Despite the fire behavior of the single thermal insulation materials is known, the fire performance of the finished façade system is not yet predictable.This paper describes a proposal of a new medium‐scale test method to evaluate the fire behavior for façades with external thermal insulation composite system (ETICS). The project aimed to identify a test protocol conceived to be repeatable, versatile, and able to provide the relevant evaluation fire hazard quantities required for performing a fire risk assessment. Furthermore, the fire hazardous quantities collected during the test could also be useful for a fire performance‐based design using fire safety engineering to define building fire safety requirements, occupant evacuation systems, the safety of rescue teams intervention and for estimating residual damage on the building and the adjacent ones after the outbreak of a fire.

Preface

It is our great pleasure to welcome all of you to 2020 7th International Conference on Coastal and Ocean Engineering (ICCOE 2020) April 22-24, 2020, Singapore. ICCOE 2020 is dedicated to issues related to Coastal and Ocean Engineering.Due to the COVID-19 pandemic, the conference committees made a decision to hold an online conference instead to ensure every participant’s personal safety.CCOE 2020 is highlighted with four keynote speakers: Prof. Gordon Huang (University of Regina, Canada); Prof. Chou Loke Ming (National University of Singapore, Singapore); Prof. Koh Hock Lye (Sunway University, Malaysia); Associate Professor Edmond Yat-Man Lo (Nanyang Technological University, Singapore).The Conference had one poster session and four oral sub-sessions on different topics: Environmental Science and Engineering, Innovation and Economic Development, Ocean Engineering, Marine Science and Ship Engineering.It was a great opportunity for students, researchers and engineers to interact with the experts and specialists to get advice or consultation on technical matters, dissemination and marketing strategies.This volume of the proceedings presents a selection of papers submitted to the conference. They are organised in nine chapters under the topics of: Utilization of Ocean Space, Marine Resource Exploitation, Utilization of Ocean Energy, Ship Engineering, Marine Dynamics, Architectural Design, Fire Safety Engineering, Environmental Science and Technology, and Economic Innovation. All papers were subjected to peer-review by conference committee members and international reviewers. The papers were selected based on high quality and relevance to the conference theme.We express our sincere appreciation to the organizing committee and the volunteers who had dedicated their time, effort and help in planning, promoting, and organizing the conference.Prof. Chou Loke MingNational University of Singapore, Singapore2020-04-29

Evaluation of the room smoke filling time for fire plumes: Influence of the room geometry

SummaryThe article examines numerically and theoretically the effects of room aspect ratio on the fire smoke filling process. It aims to evaluate the two‐zone models used in fire safety engineering to predict the smoke filling times. Using Fire Dynamics Simulator, numerical simulations are performed and compared to a simplified zone model. The results show that the two‐zone model overestimates the smoke filling time in the case of a compartment with a large surface area. To improve the predictions of two‐zone models, simple correlations are established for the duration of the phenomena occurring before the formation of a two‐layer stratification in a fire compartment. These new correlations allow the zone model to be significantly improved.

Risk Index Method–A Tool for Sustainable, Holistic Building Fire Strategies

Modern fire safety engineering seeks to ensure buildings are safe from fire by applying optimum levels of fire safety and protection resources without the need to overprotect. Similarly, the principles of sustainability aim to ensure resources are suitably applied to meet social, economic, and environmental objectives. However, there is a mismatch between the actual application of fire safety and the sustainability objectives for buildings, typically caused by the highly prescriptive historical approaches still largely adopted and legislated for in many countries. One solution that is increasingly adopted is the more flexible, “performance-based” fire engineering approach that bases fire safety and protection provisions on the development of key performance objectives, some of which could be influenced by sustainability engineering propositions for buildings, but very often this does not appear to be enough. The proposed new concept prompts separate assessment and scoring of the eight most important fire safety factors, allowing for calculation of the fire strategy risk index (FSRI). By comparing the FSRI of the actual submitted strategy against the baseline strategy, enforcement agencies or other interested stakeholders will have a methodology to determine optimal fire safety solutions for buildings.

Member and structural fragility of reinforced concrete structure under fire

Purpose Despite recognizing the significance of risk-based frameworks in fire safety engineering, the usual approach in structural fire design is largely member/component level, wherein effect of uncertainties influencing the fire resistance of structures are not explicitly considered. In this context, a probabilistic framework is presented to investigate the vulnerability of a reinforced concrete (RC) members and structure under fire loading scenario. Design/methodology/approach The RC structures exposed to fire are modeled in a finite element (FE) platform incorporating material and geometric nonlinearity, in which the transient thermo-mechanical analysis is carried out by suitably incorporating the temperature variation of thermal and mechanical properties of both concrete and steel rebar. The stochasticity in the system is considered in structural resistance, thermal and fire model parameters, and the subsequent fragility curves are developed considering threshold limit state of deflection. Findings The fire resistance of RC structure is reported to be significantly lower in comparison to the RC members, thereby illustrating the current prescriptive design approaches based on studies of structural member behavior to be crucial from a safety and reliability point of view. Practical implications The framework developed for the vulnerability assessment of RC structures under fire hazard through FE analysis can be effectively used to estimate the structural fire resistance for other similar structure to enhance safety and reliability of structures under such extreme threats. Originality/value The paper proposes a novel methodology for vulnerability assessment of three-dimensional RC structures under fire hazard through FE analysis and provides comparison of the structural fragility with fragility developed for structural members. Moreover, the research emphasizes to assume 3D behavior of the structure rather than the approximate 2D behavior.

Developing and validating evacuation models for fire safety engineering

Evacuation models can adopt different approaches for the simulation of human behaviour in fire. This paper provides an overview of the most commonly used modelling methods to represent the evacuation process in a fire scenario. This is presented through a structure matching the engineering time-line model of evacuation. The evacuation model development process is discussed considering both data-driven empirical correlations as well as theory-based modelling approaches. Examples of alternative methods to the currently used evacuation modelling assumptions are also presented. These methods have been chosen to provide examples of cases in which revisions of well-established assumptions may be needed. This review mainly focuses on buildings and pedestrian evacuation scenarios. Nevertheless, many concepts presented are potentially applicable to traffic evacuation. Particular attention is given to the representation of the impact of smoke on the evacuation process, as this is an important issue for fire safety engineering. Finally, a discussion on existing methods and procedures for the verification and validation of evacuation models is presented and the need for their standardization is advocated.

Adequate fire safety for structural steel elements based upon life-time cost optimization

Structural fire safety requirements implicitly balance up-front investments in materials (protection or element sizing) with improved performance (loss reductions) in the unlikely event of a fire. For traditional prescriptive fire safety recommendations, the underlying target safety levels are not clear to the designer, nor is the associated balancing of risk and investment costs.It is discussed that traditional (structural) fire safety design is deterministic, with the safety foundation premised upon the collective experience of the profession. However, it is noted that building forms are increasingly uncommon in nature, due to material choice, height, failure consequences, etc. Within the framework presented in PD 7974–7:2019 there is an expectation that probabilistic risk assessment (PRA) methods be employed to demonstrate adequate safety for cases where the collective experience of the profession cannot be called upon to guide design approaches. In doing so, any design must be demonstrated to be tolerable to society, and the residual risk as low as is reasonably practicable (ALARP).In support of the PD 7974–7:2019 framework, the paper assesses the failure probabilities of isolated steel elements in function of insulation thickness, utilization, load ratio and (mean) fire load. In support of a generalized definition of target safety levels for structural fire safety engineering, optimum target safety levels for insulated steel beams are then determined as a function of the fire characteristics by applying life-time cost optimization (LCO) techniques. The LCO results in an assessment of the optimum investment level as a function of the fire, and damage and investment cost parameters characterizing the building. It is intended that the current contribution can be a steppingstone towards rational and validated reliability targets for performance-based design (PBD) in structural fire safety engineering.

Evaluation of a zone model for fire safety engineering in large spaces

Thanks to simple and straightforward calculation methods it is rather easy to estimate gas temperatures in small- or medium sized enclosures; however, the problem becomes more complex if fire safety analyses are to be performed in large spaces where the hot gas layer cannot be regarded as uniform. Using a multi-zone modelling concept could be a good alternative for such situations. However, few such models exist and the evaluation of the concept is scarce. This paper is therefore dedicated to study the multi-zone modelling concept and its usefulness in fire safety engineering by comparing results from such a model with results from a more established numerical method as well as experimental data. The results indicate that the multi-zone model gives reasonable estimates of gas temperatures in well-ventilated large spaces. It is also concluded that there is a potential for the multi-zone concept to be a complement to more advanced numerical modelling methods like Computational Fluid Dynamics.

The impact of carrying load on physical performance during ascending evacuation movement

SummaryThis study investigates how ascending movement is affected by carrying load during a stair‐climbing motion. The methods adopted are based on exercise physiology and fire safety engineering. Experiments with 21 volunteers with mean (SD) age of 27 (4) have been carried out on a stair machine with or without carrying a mass of 8 kg, typical weight of a hand luggage or the average weight of an 8‐months old infant. Oxygen uptake (V˙O2), heart rate (HR), metabolic rate (M), and perceived exertion results showed a decrease in performance in the scenario with additional load. Participants climbed an average of 92 m without carrying a load, in comparison to 84 m when they were carrying it in a 5 minutes task. An average increase of 4% in the V˙O2 and the HR was found in the experiments with the additional mass. The strongest correlating variables observed were M and the vertical distance covered. Differences in perceived exertion occurred after four minutes into the exercise, with higher values in the case with additional load. These results show the need for considering the negative impact of carrying load while designing infrastructures in case of ascending evacuation and while developing evacuation modelling tools.

Safe Evacuation for All A top 10 List of Requirements

Evacuations are an important aspect of emergency planning. Many persons with special needs could reach a safe area on their own or with assistance by other people around, if evacuation planning and guidance considered them. The so-called self-rescue is crucial for safe evacuation, as fire services and other first-responders need some time to arrive at the scene. In general, people should find the conditions to arrive at a safe area on their own. In many buildings and infrastructures today, self-rescue is difficult for persons with special needs, e.g. wheelchair users. Sometimes it appears that designers and fire safety engineers only think of “average”, healthy and agile people in evacuations. But for safe and effective evacuations, different groups of people and their needs have to be considered. The paper suggests a top 10 list of requirements for safe evacuation and improvement of self-rescue from a psychological point of view. Universal Design or Design for All in evacuation has become more relevant in recent times, since accessibility as a political goal has made it possible for persons with special needs to participate more easily in public life. Nonetheless, regulations focus on how people enter a building but not on how to evacuate safely. Preparing for safer evacuations requires knowledge about different occupant groups and their needs. Requirements for different phases of evacuations are discussed and their implications for simulation and modelling, e.g. the potential impact of physiological requirements. The need for a multi-method approach to gather and integrate data, factors to foster safe evacuations, just as practical and design requirements are included. When self-rescue is not possible, assisted evacuation will rely on good leadership fostering social motivation. Last but not least, implementing design for all will help everyone to evacuate safely.

RUIM – A fire safety engineering model for rural urban interface firefighter taskforce deployment

Firefighting at the rural urban interface remains one of the most dangerous activities undertaken by fire services internationally. Whilst there is a significant volume of literature and describing methods for fire engineering safety analysis in the urban environment, a significant gap remains in the context of the rural urban interface. To address this, this article presents the Rural Urban Interface Model (RUIM). An adaptation of the Fire Brigade Intervention Model (FBIM), the RUIM enables systematic analysis of firefighter safety during catastrophic and dynamic wildfire events. When applied correctly, the RUIM provides additional guidance to Incident Controllers and Incident Management Teams regarding the suitability and safety of defensive firefighting strategies. Ultimately, the inclusion of the RUIM as part of operational fire ground analysis may reduce the potential for fatalities or injuries arising from firefighting taskforces being caught in wildfire burnover.

A Review of Battery Fires in Electric Vehicles

Over the last decade, the electric vehicle (EV) has significantly changed the car industry globally, driven by the fast development of Li-ion battery technology. However, the fire risk and hazard associated with this type of high-energy battery has become a major safety concern for EVs. This review focuses on the latest fire-safety issues of EVs related to thermal runaway and fire in Li-ion batteries. Thermal runaway or fire can occur as a result of extreme abuse conditions that may be the result of the faulty operation or traffic accidents. Failure of the battery may then be accompanied by the release of toxic gas, fire, jet flames, and explosion. This paper is devoted to reviewing the battery fire in battery EVs, hybrid EVs, and electric buses to provide a qualitative understanding of the fire risk and hazards associated with battery powered EVs. In addition, important battery fire characteristics involved in various EV fire scenarios, obtained through testing, are analysed. The tested peak heat release rate (PHHR in MW) varies with the energy capacity of LIBs ($$E_{B}$$ in Wh) crossing different scales as $$PHRR = 2E_{B}^{0.6}$$. For the full-scale EV fire test, limited data have revealed that the heat release and hazard of an EV fire are comparable to that of a fossil-fuelled vehicle fire. Once the onboard battery involved in fire, there is a greater difficulty in suppressing EV fires, because the burning battery pack inside is inaccessible to externally applied suppressant and can re-ignite without sufficient cooling. As a result, an excessive amount of suppression agent is needed to cool the battery, extinguish the fire, and prevent reignition. By addressing these concerns, this review aims to aid researchers and industries working with batteries, EVs and fire safety engineering, to encourage active research collaborations, and attract future research and development on improving the overall safety of future EVs. Only then will society achieve the same comfort level for EVs as they have for conventional vehicles.

An Online Survey of Pedestrian Evacuation Model Usage and Users

Pedestrian evacuation models are often used to assess life safety in the performance-based design process within fire safety engineering. Within this paper, a summary of data collected via an international online survey regarding the models and users’ experiences and needs is presented. This survey consisted of 22 questions focusing on: the assessment of the pedestrian evacuation model user community; their stated importance of model features to select a model; usage/awareness of models; knowledge of model validation and verification; training; and usage of multiple models. As such, the survey allowed the collection of information useful for instructing future pedestrian evacuation model development. The survey represents an expanded version of a previous survey conducted by the authors in 2011. Results with the previous survey were compared to identify any changes in preference and usage by pedestrian evacuation model users. The survey was completed by 234 respondents from 41 countries. The respondents had a wide range of education and occupational backgrounds and use models for a variety of different purposes. The results identified a total of 72 pedestrian evacuation models currently in use and indicated the most known models. In addition, the most used models were identified, and the results highlighted that the three key factors used to select a pedestrian evacuation model are overall consistent with the results of the 2011 survey: verification and validation, documentation, and data output of the model.

Fire performance of cultural heritage and contemporary timbers

Cultural heritage buildings are important reminders of our history, and timber is one of the materials commonly found within these structures. While cultural heritage buildings often hold significant aesthetic, historic, or cultural value, they are also frequently vulnerable to fire. In order to improve the fire performance of these buildings, the timber elements are often removed or covered by another material. When these alterations are done, the heritage value of the building is obscured. On the other hand, increasingly larger and taller timber buildings are being constructed out of contemporary/engineered timber, and fire safety engineering strategies have been found to justify the adequate fire performance of these contemporary structures. This manuscript herein addresses if historic timber performs significantly different to contemporary timber in fire. Controlled and repeatable fire tests have been performed on four different types of timber, two contemporary Glued Laminated Timbers (Glulam) and two historic timbers from buildings constructed in 1898 and 1839. The timber was tested using Lateral Ignition and Flame Spread Test and Cone Calorimeter apparatuses, following ASTM E1321 and ASTM E1354 standards, to compare the relative performance of the timber types in their char depth, time to ignition, and flame spread. Results showed that the historic timber did not perform as well as the Glulam in the aforementioned categories, with the historic timber charring at a rate up to 20% faster. This study is novel by providing an indication of the fire performance of timber that was used hundreds of years ago, by comparing it to timber used today. Successful heritage conservation efforts in leaving the timber exposed and in-place become possible once the performance of the timber is understood, and other fire safety engineering strategies (respectful of the heritage structure) are in place.

Closing the gap: Merging engineering and anthropology in holistic fire safety assessments in the maritime and offshore industries

This article reports on the endeavor to merge the fields of anthropology and fire safety engineering in holistic fire safety assessments within the maritime and offshore industries. The article suggests a combination of the two disciplines to transition from an interdisciplinary approach towards transdisciplinarity. The approach has been developed and adjusted during three cases of risk analyses and prevention strategies on fire safety. The article presents two methodological insights illustrating the necessary attitude of interdisciplinarity as a foundation towards transdisciplinarity. It advocates for the need of willingness in organizations and project teams to consider both disciplines as equally valid, integrate them in research definition, and create a base for common understanding. Subsequently, it is proposed that transdisciplinary work requires the creation of a group of core members acting as guarantors of transdisciplinarity, thus becoming themselves transdisciplinary humans working in a joined framework of thinking and methods. The article also presents two operational findings integrating the two disciplines within the area of fire safety. The first finding concerns including ‘daily operations’ in fire safety design, as daily practices and perceptions among crew can have a high impact on fire safety. The second finding concerns ‘reclassification of space and place’. It highlights mixing and shifting between work- and leisure-related practices within the same physical space, leading to the identification of new fire scenarios. It also explores the shifts between work, leisure, and emergency places, and their link to the shifts in professional roles of crew.

Assessing the influence of the input variables employed by fire dynamics simulator (FDS) software to model numerically solid-phase pyrolysis of cardboard

Understanding a material’s fire behaviour implies to know the thermal decomposition processes. Thermal analysis techniques are widely employed to study thermal decomposition processes, especially to calculate the kinetic and thermal properties. Cardboard boxes are widely employed as rack-storage commodities in industrial buildings. Hence, the characterization of the cardboard is considered a key factor for fire safety engineering, because it enables the determination of its thermal behaviour at high temperatures. The employment of mathematical or computational models for modelling the thermal decomposition processes is commonly used in fire safety engineering (FSE). The fire dynamics simulator (FDS) software is one of the most commonly used computational fluid dynamics softwares in FSE to address thermal analysis. To properly set up FDS and obtain accurate results, the numerical values of the thermal and kinetic properties are needed as input data. Owing to the large number of variables to be determined, a preliminary study is bound to be helpful, which can well assess the influence of each variable over the pyrolysis model, discarding or restricting their influence. This study, based on the Monte Carlo method, presents a sensitivity analysis for the variables utilized as input data by the FDS software. The results show the conversion factor α, i.e. the mass involved in each reaction, and the triplet kinetics have a major impact on the reproduction of the thermal decomposition process in fire computer modelling.

Physical modeling of a fire with the use of the Froude number

Ever since the field of Fire Safety Engineering first came into existence, small-scale (model scale) fire tests were the source of much valuable information about the phenomena occurring during combustion. Over the years, several computational methods to determine the criteria for the similarity of fires on both a real and small geometric scale have been developed. The purpose of this article is to present a method of performing fire tests on a model scale using the Froude number. The basics of scaling, similarity conditions that must be preserved, ways of describing fire phenomena, as well as methods of calculating fire parameters from the real and model scale have been discussed. An example of physical tests with the use of reduced research models is also presented. What is particularly emphasized is how important these types of experiments are and what responsibility rests with the people who carry them ouvol. The motivation to conduct research is the safety of people who reside in buildings with fire protection based on model scale test.

An Alternative Evaluation and Indicating Methodology for Sustainable Fire Safety in the Process Industry

There is a mismatch between the desire to introduce greater levels of sustainability in engineering design and in the need to provide effective engineering solutions, particularly where issues of human safety and asset protection are involved. Sustainability engineering typically incorporates economic, environmental, and social factors, all of which are highly relevant and applicable to fire safety and the design of fire protection systems. The term fire strategy denotes a documented methodology to encapsulate a full range of such systems, within a single framework, for more complex risks such as those found in the process industry. The subject of fire safety is emotive and its application within building design may not change unless we refocus on a holistic and strategic approach, especially for complex building profiles. Fire is a recognized critical safety issue for most types of industrial plants. Due to the complexity of the processes, even a relatively small fire accident can lead to a chain of events that could be devastating, resulting in huge asset and continuity losses, damage to the local environment, and of course, the threat to life. More complex processes require a more flexible and relevant approach. The use of fire safety engineering and performance-based evaluation techniques, instead of prescriptive rules, continues to grow in prominence because of this. This is the case when specifying fire protection and safety for modern power generating plants. However, when it comes to critical infrastructure, such as is the case with power plants, it is sometimes not clear whether optimum fire safety engineering solutions have been applied. One of the ideas specifically developed for evaluating the most appropriate fire safety strategies and systems, especially for such infrastructure examples, is a method based upon the British Standard Specification PAS 911. This method is captured in a diagram and identifies eight main elements for fire safety and protection. The idea presented in this article is to allow assessment of a submitted actual fire strategy for a building or other form of infrastructure, against what has been predetermined as a standard baseline fire strategy for, in this case, a power plant building. The assessment makes use of a multi-level questionnaire, in this case specifically formulated for power plant fire safety needs. By comparing the actual fire strategy diagram against a baseline fire strategy, enforcement agencies, or other interested stakeholders, can recognize which fire safety factors play the most important part in the fire strategy, and determine whether proper levels of fire safety and protection have been applied. The fire strategy evaluation is realized by a team of engineers, which consists of independent fire strategist from a consultant office, internal fire and technical experts from the industrial plant, such as the person responsible for fire safety, person responsible for explosion safety, person responsible for housekeeping, and building manager. Additionally, there should be representatives of insurance companies and independent fire experts. Typically, the group consists of 7 to 12 people.

Experimental Characterization of a Smoke Flow in a Small Length Corridor

Smoke propagation into a corridor configuration is an important issue in fire safety engineering. One important characteristic is the smoke behaviour in the steady state, namely, the smoke layer thickness, its mean temperature and its mean velocity. The question that is investigated here is how these quantities vary as a function of the corridor geometrical characteristics and of the fire heat release rate. To achieve this goal, new experimental data are provided in a small scale configuration. The results show that the smoke layer thickness is independent of the heat release rate of the pool fire. By rescaling the velocity and temperature profiles with respect to the fire heat release rate, these profiles fall onto unique curves. Finally, based on energy and mass conservation equations, a scaling relation is proposed for the smoke enthalpy.