Fire Safety Analysis Research Articles

Indicators for the Quality Assessment of the Grid Resolution

The choice of the grid resolution in thermo-fluid dynamics simulations is to be made as a balance between the quality of the results and the computational effort. When quick results are needed, coarse resolutions are often used, but in some cases this could be detrimental for the reliability of the numerical results. However, it is well known that reducing the size of the mesh affects dramatically the overall simulation time.Several approaches can be used to ensure that the mesh size is appropriate to reproduce the fire and smoke dynamics for a given scenario with suitable computational effort and make reliable predictions.The first and most used approach consists of limiting the ratio between the characteristic fire diameter D* and the grid size dx inside a range based on a series of experimental tests reported in literature. This approach is generally used as a first step in order to define a tentative grid resolution for the given model.Other approaches consist of checking if some indicators are included in a literature-based range once the simulation has run. For example, the dimensionless parameter y+ is a measure of how well the near-wall field is solved and can be effectively useful when the roughness of the walls affects the overall flow field. The measure of turbulence resolution (MTR), instead, is a quantity related to the resolved i.e. calculated turbulent kinetic energy and gives an idea of how detailed the turbulence effects are accounted in the model.These indicators are certainly a significant source of information regarding the quality of the model as well as the need of local refinement. However, they are not a guarantee for the achievement of convergent results of the quantity of interest (e.g. temperature, visibility, FED) which from the engineering point view are as valuable as the quality assessment of the model.In the paper, the traditional indicators are reviewed from a theoretical point of view and the Pearson’s coefficient is introduced as an attempt to add other statistical correlation principles. The purpose is to couple mesh quality metrics with a global convergence check of the quantity of interest of the fire safety analysis, driven also by aspects of conservativeness and computational cost. An application to a case study is also provided and shows pros and cons of the indicators.

Thermal and fire risk analysis of low pressure on building energy conservation material flexible polyurethane with various inclined facade constructions

This study investigated the factors affecting the fire safety analysis of the common construction material flexible polyurethane foam, based on combustion at various inclination angles and the ambient pressures at the altitudes of the cities of Hefei (99.8 kPa) and Lhasa (66.5 kPa). The effects of ambient air pressure, specimen width and inclination angle on the burning rate (as determined by mass loss), average flame spreading velocity, flame temperature and flame length were examined. The combustion rate was lower at 66.5 kPa and the wider specimens exhibited gradual spreading of the flame front in conjunction with melting and dripping. The burning rates at various inclinations were found to correlate with the pressure according to the expression ṁ∝pn,0.67<n<1.36, and this result can be explained based on pool fire theory. The average flame spreading velocity was found to correlate with pressure at various inclinations according to the relationship Va∝pn,2/3<n<1. The flame temperature was also observed to increase somewhat at the lower pressure, leading to an increase in the flame puffing frequency. Finally, a power law was used to describe the relationship between flame height and pressure, while a linear relationship was obtained between the index and the angle of inclination.

АНАЛИЗ ПОЖАРОВ В РЕСПУБЛИКЕ КАЗАХСТАН МЕТОДАМИ МАТЕМАТИЧЕСКОЙ СТАТИСТИКИ

Aims. The aim and objective of the study is to adapt the methods of mathematical analysis to the assessment of fire safety of municipal entities of the Republic of Kazakhstan. Methods. The methodological basis of the study is the theory of mathematical statistics. Up to date, the fire safety assessment by means of mathematical statistics has not been carried out in the Republic of Kazakhstan. It is impossible to solve the problem of increasing the level of fire safety in the regions of the Republic of Kazakhstan without such studies. Therefore, there is a need to adapt the known methods of mathematical statistics of fire safety in the Republic of Kazakhstan, to carry out such an assessment, which makes it possible to characterize security for 16 regions of the Republic of Kazakhstan that determines the relevance of the study. Applying the methodology of mathematical statistics of fire safety is necessary for making managerial decisions to ensure the necessary level of fire safety of regions on the basis of limit interval values. Results. A sequential mathematical analysis of fire safety in the republic was carried out. On the basis of the results of the study, limit interval values of fire safety for 16 regions of the Republic of Kazakhstan are justified. According to the results of the analysis, it is determined that the interval values of fires for the regions of the republic are 945 f (16) < 1056, in Karaganda, East Kazakhstan, Pavlodar, Kostanay and Almaty regions, the number of fires in the period from 2005 to 2016 were beyond the limits of the right value of the interval. In this connection, the situation with fires was worse in these regions than in the republic. Field of application of scientific results. The obtained results can be used by both local executive and authorized bodies in the field of fire safety when developing appropriate management solutions to reduce the fire risk, as well as when developing a fire fighting service. Conclusion. The conducted mathematical analysis of fire safety in the regions of the Republic of Kazakhstan has shown that in the five regions of the republic (Karaganda, East Kazakhstan, Pavlodar, Kostanay and Almaty regions) between 2005 and 2016, the level of fire safety was worse than the average republican rate. In this connection, work on implementation of management decisions to minimize fire danger to the boundaries of the confidence interval should be strengthened in the local executive bodies and authorized bodies in the field of fire safety of these regions. The proposed approach to assessing fire safety levels is advisable to use in the design of fire departments and allocation of funds for the implementation of activities to reduce fire risks in the relevant territories.

Fire Safety Analysis of Nanjing Yangtze River Tunnel Based on Fault Tree and Triangle Fuzzy Theory

Abstract In order to realistic study of fire accidents in tunnel, according to the uncertainty and fuzziness of accident, the model of fault tree is established for Nanjing Yangtze River Tunnel after Nanjing Yangtze River Bridge closed, and with the triangular fuzzy theory, the estimate of base event is obtained by scoring of the relevant professional, and the probable range of top event is calculated. In addition, the fuzzy importance is obtained by the median method of triangular fuzzy theory, to find the fuzzy importance of basic event. Then the fire prevention measures are proposed for Nanjing Yangtze River Tunnel. The results show that the possibility of uncontrolled fire is small in Nanjing Yangtze River Tunnel. Among them, fire rescue no arriving in time, no knowledge of fire extinguishing, vehicle collision on fire and auto-alarm failure are main factors leading to catastrophic fire. Thus, it is of great significance to strengthen the fire-fighting knowledge of personnel and the capacity of automatic fire-fighting for the tunnel itself, to reduce the occurrence of fire in tunnel.

Aamks: the platform for assessing fire safety of humans in buildings

We introduce an open-source software for fire risk assessment named Aamks. We provide a brief overview of the following aspects of the platform: the motivation for creating Aamks, the architecture of the platform, the user interface, the intended workflow for conducting fire safety analyses, the probabilistic approach to fire risk assessment, the geometry processing, the reasoning from the topology of the building (i.e. automatic planning of exit routes), the interactions amongst the moving evacuees, the impact of smoke on humans and finally the results and the visualization.

Fire Safety Analysis of Building Partition Wall Engineering

Building partition wall, as one of the building partition constructions, and as one of the major renovation projects of the decoration and renovation engineering in commercial and official buildings, it often has an effect on the project’s fire safety. In this article, the type, structure and materials of partition walls are summarized in classification, factors affecting the fire performance of building partition walls are analyzed, and problems of partition walls in engineering and fire protection designing are illustrated and analyzed. International and national standards are analyzed. Through discussions on fire safety audit and setting of partition walls, the adverse effects of partition wall renovation projects on building structures, damage to fire prevention compartment, impact on evacuation route of people, smoke control design and on other fixed fire protection facilities, are discussed in this article. It can be seen from these projects, if building partition walls were designed improperly, it would do great harm to building fire safety. Therefore, it should be taken seriously in fire safety designing. Some suggestions on the problems in the application of partition wall engineering are proposed, which can provide references for fire prevention designing.

Analysis of nuclear fire safety by dynamic complex algorithm of fuzzy theory and system dynamics

The cognitive architecture is investigated for the disaster management in the nuclear accident site. The fire-based nuclear facility catastrophe is a very significant considerable factor in the aspect of the nuclear safety. There are simulation results as the graphs by each time step composing of the simulations of 3 factors of Fire Caution, Fire Control, and Personal Factor. Each graph shows the instability of the designed event. There is the simulation result for Instability of Fire Protection System. The highest value is 0.67584 in 56th year in which the system is very unstable in fire protections. In the graph, the later time part of the operations has higher values comparatively. This could be explained by the system aging of the plant. In the system dynamics (SD) method combined with fuzzy set algorithm, the tractable modeling is liable to be adapt to any kinds of situations in the NPPs. Needless to say, the complex algorithm could be usable in the cases of normal as well as emergency circumstances.

Modernization of Fire Extinguishing Installations at Ukrainian NPPs

Fire safety of nuclear power plants is a relevant task, which shall be solved using the latest approaches taking into account NPP design and construction practices, including those in foreign countries.&#x0D; The paper describes results of analysis of NPP fire safety in Ukraine based on national and international assessments, identifies problems in this area and presents priority measures aimed at NPP safety improvement, in particular modernization of fire protection of safety system rooms and implementation of gas and powder fire extinguishers at Ukrainian NPPs.

Assessing fire safety using complex numerical models with a Bayesian multi-fidelity approach

Nowadays, fire safety engineers are increasingly relying on sophisticated numerical simulators, typically based on Computational Fluid Dynamics (CFD) solvers, to conduct their analyses. However, the complexity of these numerical models often limits drastically the number of simulations that can be afforded, making traditional methods of safety analysis difficult or impossible to apply. This paper proposes a statistical method to evaluate a quantity of interest with an expensive simulator while saving computation time. The method is based on Bayesian statistics and multi-fidelity. We use Gaussian process regression to construct a Bayesian model of the complex simulator. This model is based on a multi-fidelity approach, which consists in simulating at different levels of accuracy, for instance by varying the spatial discretization in a CFD solver. We illustrate the method on an example of fire safety analysis, where the quantity of interest is the probability of exceeding a tenability threshold in a building on fire.

System and Subsystems Used in the Engineering Approach of Human Evacuation in Case of Fire

The new approach of human evacuation in case of fire, the engineering one, offers additional possibilities of assessment for this activity included in the issue of fire safety of buildings. Being a relatively new field of study, less known to professionals specialized in fire safety (but quite well known to specialized researchers), fire safety engineering undergoes permanent reorganization at the level of concepts and procedures, information by mean of which it operate, due to the rapid accumulation of experience in this area of engineering activity; therefore, after countries such as Australia, Canada, New Zealand, USA have provided to their specialists normative regulations specific to fire safety engineering, groups of specialists from these countries have joined their efforts to try reducing the differences between these regulations and give a unified, better conceptualized approach to fire safety engineering. The result: the development of International Fire Engineering Guidelines (last edition 2005). The systemic approach to fire safety in buildings outlined, once again, the possibility of modular organization of this field of study, the relations between modules depending on the objectives followed in a fire safety analysis for a specified building. This article intends to present in this modularized perspective, human evacuation in case of fire from a building designed for higher education, with a centrally located atrium.

Methods of traction rolling stock fire safety analysis

Aim. Fire safety of a protection asset is the state of a protection asset that is characterized by the capability to prevent the occurrence and development of fire, as well as the effects of hazardous factors of fire on people and property [1]. The traction rolling stock (TRS) is one of the primary protection assets on railway transport. Managing TRS fire safety involves a large volume of information on various TRS types: possible fire-hazardous conditions, fire safety systems, parameters of TRS-related processes. That means that efficient management must be built upon analysis that allows identifying trends and factors of fire hazard development. The analysis should be organized in such a way as to allow its results to be used in evaluation of composite safety indicators [2]. The required applied nature of such analysis is also obvious. Given the above, it should be noted that the applied research indirectly solves the task of using the results of fundamental research to address not only cognitive, but also societal issues [3]. The aim of this article is to structure the most efficient applied and theoretic methods of analysis and to develop a structure for systems analysis of TRS fire safety. Methods. The multitude of factors that affect the condition of TRS can be divided into two groups: qualitative and quantitative. Importantly, it is impossible to completely research the impact of all the elements of a complex technical system that is TRS on fire safety. We have to examine a part of the whole, i.e. a sample, and then use probabilistic and statistical methods to extrapolate the findings of sample examination to the whole [4]. An analysis of a data set requires a correctly defined sample. At this stage, the quality of information is the most important criterion. The list of raw data was defined based on the completeness of the description, reliability of the sources. Then, in a certain sequence, the data was analyzed by means of qualitative and semi-quantitative methods. First, given the impossibility to establish evident connections (destroyed by the hazardous effects of fire) between the condition of units that preceded the fire, the Pareto analysis was used. The research involved root cause analysis (Ishikawa diagram). Subsequently, cluster analysis of fire-hazardous situations was used. The main purpose of cluster analysis consists in establishing generic sequences of events that entail TRS fires. For that purpose, a description of possible fire-hazardous states of traction rolling stock is required, i.e. a multitude of events and states must be described. Dependability analysis can be successfully performed by representing the safety state information in terms of the theory of sets [5]. The sets of hazardous fire-related TRS events are represented in the form of partially ordered sets. Processing of such sets that are non-numeric in their nature cannot be performed by means of statistical procedures based on addition of parametric data. For that reason the research used mathematical tools based on the notion of type of distance. A part of data that have quantitative characteristics was analyzed statistically. Results. The TRS fire safety data analysis methods presented in this article that include methods of numeric and non-numeric data processing allowed developing a formatted list of fire hazard factors that enable the creation of a practical method of TRS fire risk calculation. An algorithm is proposed for application of qualitative and quantitative methods of analysis of data of various numerical natures. An example is given of the algorithm’s application in the analysis of diesel engine fire safety. The proposed method can be used for analyzing anthropogenic safety in terms of listing the factors involved in risk assessment.

Methodology for estimating pyrolysis rates of charring insulation materials using experimental temperature measurements

This paper presents the application of a simplified method to estimate pyrolysis rates from rigid closed-cell cellular plastics by means of experimental temperature measurements. These materials are extremely effective in meeting energy efficiency goals in buildings and their safe use should also be enabled and optimised by undertaking comprehensive fire safety analyses. The proposed methodology consists of determining the mass loss as a function of the thermal evolution by applying a mass conversion directly using thermogravimetric data under non-oxidative conditions. In order to verify this simplified method, an experimental programme based on 100mm thick samples of rigid polyisocyanurate foam was conducted using a Cone Calorimeter, obtaining measurements of mass loss and temperature within the core of the material. A Monel plate was used on top of the sample in order to represent a simpler boundary condition by eliminating the smouldering process of the charred material. Although the pyrolysis rates using this methodology did not provide a perfect fit with experimental data, they showed similar trends, with a slightly delayed prediction but still accurate magnitude. This methodology presents potential for fire safety engineering applications in two domains: (1) as a complementary technique to improve the interpretation of results from standard and ad-hoc testing, and (2) as a design technique for the evaluation of potential heat release contribution and gaseous emissions of assemblies incorporating insulation materials.

Formal Fire Safety Assessment of Passenger Ships

Fire has been a major cause of ship's accidents throughout maritime history. It is by far the most serious threat to life and the environment as passenger ships get larger and more sophisticated. It is also impossible to protect a passenger vessel against all hazards. Despite the fact that a passenger ship contains potential fire hazards in the engine room space, accommodation zone and electrical systems, etc, the single most important fire hazard onboard a ship may be the man himself, either unintentionally or intentionally. 'Fire safety on passenger vessel' has continued to be the focus of attention on passenger ships. The work described in this thesis is concerned with the application of Formal Fire Safety Assessment to passenger ships. The traditional way of conducting a Formal Safety Assessment (FSA) employs typical fire safety analysis methods that require a certain amount of data. Most fire accident data available for passenger vessels is associated with a high degree of uncertainty and considered to be unreliable. As such, the research carried out in this thesis is directed at the development of novel fire safety analysis methods to address this problem. This thesis proposed several subjective fire safety analysis methods for passenger vessels within the FSA methodology. Also, it concentrates on developing an advanced approach for passenger ships. A few novel safety analysis and synthesis methodologies are presented to integrate fire safety assessment with decision-making techniques so that fire safety can be taken into account from the concept design /operation stages of passenger ships. This is to ensure a more controlled development process permitting decisions regarding design and operation to be made based on fire safety assessment. Finally, this thesis is concluded by summarising the results of this research project and the areas where further effort is required to improve the developed methodologies.

PERFORMANCE-BASED FIRE DESIGN OF STEEL STRUCTURES OF HELSINKI OLYMPIC STADIUM

This paper presents an overview of the fire safety analysis conducted for the steel trusses of Helsinki Olympic Stadium stand. The analysis were conducted using advanced calculation models (FDS and SAFIR). It is shown that the predefined design solution (R60 fire protection with sprinklers) can be replaced by fire protection to class R15 (no sprinkler system) without sacrificing safety when some other passive protection means are applied. The good design solution in this case required highly iterative design process and smooth co-operation between client, architects, structural engineers and fire safety consultants.

Technical reliability of active fire protection features – generic database derived from German nuclear power plants

For Probabilistic Fire Safety Analysis fire event and fault trees specific to the conditions of the nuclear power plant need to be established to estimate the corresponding branch point probabilities and end states for core damage frequency. That also requires applying technical and human reliability data for fire specific event sequences. The technical reliability of fire detection systems, fire and smoke extraction dampers, fire doors and fire extinguishing systems and equipment including extinguishing media supplies has been estimated by means of their failure rates. To account for epistemic uncertainties Bayesian estimation methods have been used, depending on homogeneity of the studied components.The data has been evaluated by analyzing the documentation of periodic in-service inspections as well as additional information and reports which resulted from the inspection findings. For more complex systems, in addition to the components’ failure rates, fault trees are presented to calculate the systems reliability.This type of data now covers up to 111 plant operational years of six power reactor units of different age and type. The generic data may also be applied as a-priori information for estimating the reliability of components with similar design and equivalent inspection and maintenance practice for other nuclear power plants.

Road tunnel fire safety and risk: a review

A review concerning road tunnel fire safety and risk is presented. In particular different perspectives and methods on safety and risk are discussed. Road tunnel fire safety usually involves high uncertainty and high-stakes decisions. Thus, a wider group of stakeholders and different types of knowledge should be included in the fire safety analysis and evaluation, than what is required by technical risk analyses. It is argued that the decision process should not be separated from the design and safety evaluation as they are strongly dependent and iterative processes. Decision theory can guide the design and decision process in negotiation with stakeholders. Key parameters for the decision can be analysed through a combination of functional requirements, societal and political values, safety engineering, safety factors and systems theory. By taking an organisational viewpoint, potential latent and active errors can be analysed and a good safety culture can be engineered. In order to improve the safety culture of truck companies, regulation ensuring proper maintenance, training and quality management may be necessary in a competitive global economy.

Performance-based analysis of cylindrical steel containment Vessels exposed to fire

This paper reports the results of a numerical investigation on the structural safety assessment of a nuclear cylindrical steel containment vessel exposed to an accidental external fire condition. A coupling procedure is proposed, linking the modeling of a nearly compressible flow with input energy given by a combustion model (CFD model) and a structural thermo-mechanical analysis (FEM model), allowing an accurate evaluation of a fluid-thermo-mechanical response for the entire duration of the simulated accident. The time-temperature evolution of the burned gases, resulting from the combustion of a hydraulic leakage pool, is performed by the CFD model. The FEM model is used to obtain (i) temperature variation and, (ii) thermo-mechanical behavior and ultimate strength of the vessel. The obtained results indicate that the suggested methodology can provide reliable fire-safety analyses, ensuring that the main safety (load-bearing and containment) functions of the installation are not impaired during accidental events.

Testing the predictive capabilities of evacuation models for tunnel fire safety analysis

The scope of this paper is to test the predictive capabilities of different evacuation modelling approaches to simulate tunnel fire evacuations. The study is based on the a priori modelling (prior to the experiments) vs a posteriori modelling (after the data collection stage) of a set of tunnel evacuation experiments performed in a tunnel in Stockholm, Sweden. Different degrees of modelling sophistication were employed: (A) the analytical calculations described in the Society of Fire Protection Engineers (SFPE) handbook, (B) an individual use of evacuation models and (C) a multi-model approach, presented in this paper for the first time. Six evacuation models were employed, namely FDS+Evac, BuildingEXODUS, STEPS, Pathfinder, Gridflow and Simulex. The author has a priori simulated the experiments with different degrees of modelling sophistication. The experimental results were used to simulate a posteriori the same scenarios. Results showed that: (1) the use of model default settings produced significant differences in the results, (2) the calibration of models input required different degrees of effort in relation to the sophistication embedded in the model, i.e., whether it used deterministic assumptions or not, (3) analytical calculations were not a sufficient method to simulate complex tunnel evacuation processes, i.e., exit choice in smoke, (4) the use of a single model was not sufficient if the modellers had not information to calibrate the input, (5) the multi-model approach was a useful tool to test the sensitivity of the results to the model employed and the model sub-algorithms.

A simplified model for predicting the ignition of FRP composites with validation using intermediate‐scale fire experiment data

ABSTRACTThis study presents a simplified theoretical model to predict the ignition of FRP composites of general thermal thickness (GTT) subjected to one‐sided heating. A simplified GTT heat transfer model to predict the surface temperature of GTT composite panels was developed, and the exposed surface temperature was used as ignition criterion. To validate the GTT model, intermediate scale calorimeter fire tests of E‐glass fiber reinforced polyester composite panels at three heat flux levels were performed to obtain intermediate‐scale fire testing data in a controlled condition with well‐defined thermal boundary conditions. The GTT model was also verified by using results from finite element modeling predictions. This model can be used to estimate the surface temperature increase, time‐to‐ignition, and mass loss of FRP composites for fire safety design and analysis. Copyright © 2013 John Wiley &amp; Sons, Ltd.

An Analysis of the Post-earthquake Fire Safety of Historic Buildings in Kyoto, Japan

Relative to other cities in Japan, Kyoto contains an outstanding agglomeration of historic buildings. These historic buildings are crucial for maintaining Kyoto’s irregular ranking as a historical city. However, several active faults occur near Kyoto that could cause severe seismic damage to the city. Thus, post-earthquake fire is one of the most threatening potential disasters that could destroy Kyoto’s invaluable historic buildings. Here, the post-earthquake fire safety of 2,131 historic buildings in the city of Kyoto was analyzed. This analysis was conducted by Monte Carlo simulation with a physics-based urban fire spread model that was formerly developed by the author. This scenario assumes the three following exclusive events that lead to the burn-down of historic buildings: (I) the ignition in the vicinity of the target historic building; (II) inadequate firefighting activity during the initial stage of the fire; and (III) the occurrence of widespread fire in urban areas following ignition. In general, the post-earthquake fire safety of designated and registered historic buildings was greater than that of undesignated and unregistered historic buildings. In addition, in the worst case scenario, 30% of the national treasures and important cultural properties would be damaged in the center of Kyoto city.