Fire Protection Engineering Research Articles

Philip Humphrey Thomas (16 June 1926 – 14 January 2014)

Philip Humphrey Thomas (16 June 1926 – 14 January 2014)

Quantifying life safety: Part I: Scenario-based quantification

With increasingly complex architecture, new building technologies, etc., compliance with prescriptive code requirements for life safety is often times a sub-optimal solution, overly expensive, and sometimes simply impossible. This leads to the more and more frequent use of performance-based numerical tools in fire protection engineering, especially for the life safety design. Yet the level of safety achieved using those tools remains unknown due to uncertain deterministic input parameters and more or less arbitrarily chosen safety factors. In this paper, an approach is shown to quantify the level of safety for a life safety design using probabilistic risk analysis. The resulting failure probability pf,i of a life safety design given a specific scenario i yields a metric for the safety level and allows for the objective comparison with other design approaches. Additionally, the approach considers the uncertainty of the input parameters and yields information about the sensitivity of the design to the various input parameters chosen. The methodology will be demonstrated for a multi-purpose community assembly building and the levels of safety are derived based on various scenarios and for different tenability criteria.

Overview of Problems and Solutions in Fire Protection Engineering of Wind Turbines

The wind energy industry is one of today’s leading industries in the renewable energy sector, providing an affordable and sustainable energy solution. However, the wind industry faces a number of challenges, one of which is fire and that can cast a shadow on its green credentials. The three elements of the fire triangle, fuel (oil and polymers), oxygen (wind) and ignition (electric, mechanical and lighting) are represent and confined to the small and closed compartment of the turbine nacelle. Moreover, once ignition occurs in a turbine, the chances of externally fighting the fire are very slim due to the height of the nacelle and the often remote location of the wind farm. Instances of reports about fires in wind farms are increasing, yet the true extent of the impact of fires on the energy industry on a global scale is impossible to assess. Sources of information are incomplete, biased, or contain non-publically available data. The poor statistical records of wind turbine fires are a main cause of concern and hinder any research effort in this field. This paper aims to summarise the current state of knowledge in this area by presenting a review of the few sources which are available, in order to quantify and understand the fire problem in wind energy. We have found that fire is the second leading cause of catastrophic accidents in wind turbines (after blade failure) and accounts for 10 to 30% of the reported turbine accidents of any year since 1980’s. In 90% of the cases, the fire leads to a total loss of the wind turbine, or at least a downtime that results in the accumulation of economic losses. The main causes of fire ignition in wind turbines are (in decreasing order of importance): lighting strike, electrical malfunction, mechanical malfunction, and maintenance. Due to the many flammable materials used in a wind turbine (eg. fiberglass reinforced polymers, foam insulation, cables) and the large oil storage used for lubrication of mechanical components, the fuel load in a turbine nacelle is commonly very large. The paper finishes with an overview of the passive and active protection options and the economics (costs, revenue and insurance) of wind turbines to put in context the value of a loss turbine compared to the cost and options of fire protection. We hope that this paper will encourage the scientific community to pursue a proper understanding of the problem and its scale, allowing the development of the most appropriate fire protection engineering solutions.

Enhancing Building Fire Safety Performance by Reducing Miscommunication and Misconceptions

Building fire safety is driven by regulations and technical building codes, at least as a minimum requirement. As fire protection engineers (FPEs) design fire safety measures based on requirements in the regulations, they are often viewed as the primary agents in ensuring the fire safety of buildings. However, their mission often starts with given building design features, such as interior spatial layout, exterior shape, site plan, and so forth, which are mostly determined by architects. The only exception is where the FPE is invited to assist in the project planning, feasibility and early concept design stages of a project. Regardless, architects also can influence building fire safety performance, whether or not they explicitly acknowledge or understand this. Although architects design buildings within the boundaries of the regulatory requirements, the architect’s focus is often related to the visual and spatial aesthetics of buildings linked to building form and functionality, which are not subject to the regulations. These aesthetics can sometimes compete with fire safety objectives. As such, buildings can be unsafe in certain situations due to unintended effects of building design features on actual fire safety performance. This research describes the relationship between architecturally conceived building design features, design expectations for fire safety systems, and the actual or conceivable fire safety performance of the building. Steps are proposed that FPEs can take to identify and address potentially competing objectives and deliver increased fire safety performance.

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 simulation model for emergency evacuation time of a library facility using EVACNET4

PurposeThe objectives of this article are to present the findings of a case study conducted to determine the optimal emergency egress time for the main library of King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, using an evacuation simulation model; discuss the importance of the use of evacuation simulation models to architects, fire protection engineers and facilities managers; and demonstrate the importance of using an evacuation simulation model in understanding evacuation performance and conducting building safety assessment.Design/methodology/approachThe authors have reviewed the published literature in the field of evacuation analysis considering level of service (LOS) as a significant factor; studied the input requirements of the evacuation simulation model EVACNET4 and estimated the same for the library facility at King Fahd University of Petroleum & Minerals; and examined selected results and validated the same using FPETool.FindingsThe study revealed that the evacuation times obtained using both EVACNET4 and FPETool for the library are different and vary 49 seconds in magnitude.Originality/valueRisk to life as a result of fire in buildings is a key concern for facility managers, architects and insurance companies. This study could be of practical help to fire protection engineers and facilities managers from the viewpoint of emergency evacuation planning in specific facilities, and to architects during the process of designing the spatial layout of the library facility, where even minor changes in the layout can have large impacts on egress time.

SCHEMA-SI: A Hybrid fire safety engineering tool-Part I: Tool theoretical basis

SCHEMA-SI is an engineering tool able to evaluate the performance of building fire safety system. It uses a dynamic hybrid model, which means that discrete events and continuous phenomenon are interconnected at each instant. The model has been developed as a tool to assist fire protection engineers in performing fire safety engineering calculations. This tool may be also used to conduct risk assessments and to evaluate whether selected design strategies are sufficiently safe in case of fire in a specific building. Part I of this paper describes the basis of the SCHEMA-SI tool. Sub-models used to perform calculations are discussed. Part II of this paper focuses on a real case study.

SCHEMA-SI: A hybrid fire safety engineering tool Part II: Case study

SCHEMA-SI is an engineering tool able to evaluate the performance of building fire safety system. It uses a dynamic hybrid model, which means that discrete events and continuous phenomena are interconnected at every instant. The model has been developed as a tool to assist fire protection engineers in performing fire safety engineering calculations. This tool may be also used to conduct risk assessments and to evaluate the efficiency of selected design strategies in case of fire in a specific building. Part I of this paper describes SCHEMA-SI tool basis. This paper focuses on a real case study. The case study aims at evaluating and comparing four fire safety strategies in a French hotel.

Development of Fire Science and Fire Protection Engineering in China

Abstract This article gives an introduction on the development of fire science and fire protection engineering in China, and a brief on the conference.

The Influence of Atmospheric Circulation on Evacuation Safety in a Semi-Open Parking Garage

This study examines the influence of the atmospheric disturbance caused by a fire in a semi-open parking garage and the resulting rapid drop of toxic gases on evacuation safety. According to a FDS simulation, the air pressure in an atmosphere of 1 kgf/m2 or a windless environment is used, each factor for hazardous escape does not reach a significant level (SFPE Handbook of Fire Protection Engineers). This indicates that even if two sides of an exterior wall are closed, in order to escape, a semi-open space is safe. However, in the industry, there is a debate on whether the influence of a different spatial format and the air pressure in the atmosphere needs to be re-assessed.

Safety Verification of Mechanical Properties of Reinforced Concrete Beam in the Fire by Applying CFD

Advanced countries have adopted performance-based protective design to evaluate safety of buildings for building’s function of fire protection. And they have employed technology of fire protection engineering and quantified data of theoretical numerical model to create an even more flexible evaluation method for building’s fire protection. Buildings suffered varied degree of attack from elevated temperature and thermal radiation, which leads to changes in physical, chemical and mechanical properties, might result in considerable damage to the buildings and their structure. Such damage threatens populace life. This paper uses FDS (Fire Dynamics Simulator) software to analyze thermal flow field of fire. The temperature boundary condition of simulation results are then entered in the CFD (Computer Fluid Dynamics) software PHOENICS to calculate internal temperature and mechanical property of the beam. This study also integrates related experimental literatures as auxiliary to calculate thermal transmission and strength. Purpose of the above is to investigate elevated temperature and reduction of mechanical property, as well as verify safety of structure.

CFD Application for Performance Based Safety Verification of Reinforced Concrete Beam in Computer Simulation Building Fire

More than 90% of the buildings in Taiwan use reinforced concrete (RC) structures. Before or after fire damage, whether the RC structure accord Performance Based Design (PBD) fire code or safe evaluation are important in building fire protection verification. However, obtaining fire thermal parameters detailed quantitative data from building fire tests or actual building fires are difficult. Therefore, computational fluid dynamic (CFD) integration to simulate fire scenarios has been widely utilized in fire protection engineering. This study utilizes Fire Dynamics Simulator (FDS) fire model and PHOENICS field model software to simulate fire development and beams inner temperature variation. The structural strength estimated using beam cross-sections temperature to investigate dynamic ultimate bending moment (Mu) of RC beams. This integration method can investigate the influence of different beam positions, fire intensity, fire duration and fire damage sustained (two or three faces heated) for RC beams fire protection safe verification.

Ultimate Strength Analysis for a Concrete Beam after a Sustained Building Fire

More than 90% of the buildings in Taiwan use reinforced concrete (RC) structures. It is crucial to human life and property to determine whether the RC structure is safe after fire damage. However, it is impossible to obtain fire thermal parameters quantitative data from actual building fires. Therefore, numerical simulation software that simulates fire scenarios was used to model fires for fire protection engineering. Beam strength decreases because of high temperature. To obtain precise beam temperature profiles in a building fire, this study used the fire model FDS and field model PHOENICS software to simulate fire development and beam inner temperature variation. Fire scenarios and beam surface temperatures in a room fire were analyzed by the FDS fire model. Beam boundary temperatures were transferred into the PHOENICS field model to compute the detailed temperature profile within the beam. The structural strength was estimated by using beam various cross-section temperatures to investigate dynamic ultimate bending moment of a RC beam in a room fire. Through the various simulations and calculations, this investigation obtained the influence of various beam positions, fire intensity, fire duration and fire damage sustained (whether two or three faces) by a RC beam after a building fire.

통계자료를 활용한 건축물 용도별 화재 위험도 분석

본 연구는 화재정책 수립에 활용 될 수 있도록 통계자료를 활용하여 건축물 용도별 화재 위험도를 정량적으로 분석하였다. 통계자료는 국가화재정보시스템 등의 4년간('07-'10) 자료를, 용도분류는 "건축법" 기준을 활용하였다. 화재위험등급 분석은 미국소방기술사회(SFPE)의 화재위험도 범위를 활용한 절대평가와 리스크매트릭스를 활용한 상대평가를 동시에 실시하였다. 그 결과 종교, 판매, 업무, 공장, 창고, 자동차, 동식물, 분묘위생, 군사교정, 발전시설의 위험등급은 SFPE기준으로 A등급으로 건물수명동안 수차례 화재가 발생할 수 있다. 리스크매트릭스를 이용한 분석에서는 숙박, 발전, 종교, 분묘위생, 판매, 군사교정, 창고, 동식물, 공장시설이 상대적으로 위험등급이 높은 IV등급 이상으로 분석되었다. 이러한 화재위험 건축물 용도에 대한 정책적 활용방안을 제시하였다. This study is analyzed fire risk quantitatively based on building use type using statistical data in order to get information applicable to the establishment of fire prevention policies. For statistical data, 4 years' data (2007-2010) from the National Fire Data System and the building classification from the Building Act were used. Fire risk was rated through both absolute evaluation using the range of the fire risk index from the Society of Fire Protection Engineers (SFPE) and relative evaluation using the risk matrix. According to the results, facilities rated as "A," has high risk of fire which fire may take place several times during the life of building. The "A" rated buildings included religious facilities, markets, office buildings, factories, warehouses, automobile facilities, animal and plant facilities, charnel and hygiene facilities, military and correctional facilities, and power generation facilities. When the risk matrix was applied to analysis the fire risk to the facilities, lodging facilities, power generation facilities, religious facilities, charnel and hygiene facilities, markets, military and correctional facilities, warehouses, animal and plant facilities and factories turned out to be have over "IV" which has the higher fire risk than other facilities. This paper finally suggested how to apply these results to government policies on facilities with fire risk.

The evaluation of different evacuation models for assessing road tunnel safety analysis

The current state-of-the-art presents a multiplicity of evacuation models for simulating emergency scenarios. Each model involves different methodological solutions to represent the same process and each one has its strengths and limitations. In addition, they have their own specific features and often practitioners do not have a thorough understanding of the variables that could be input into the models and how they will affect the results. Thus, there is a need to analyse the differences between the models, why they occur and how they affect the calculations. This study compares three evacuation models (FDS+Evac, STEPS, Pathfinder) and the analytical calculations provided in the Society of Fire Protection Engineers (SFPE) Handbook, each of them using different simulation methods. The case-study is the Lantueno tunnel in Spain (a two-bore road tunnel with an emergency link tunnel between the two bores). The results initially show that, when considering evacuation scenarios with a single available exit and favourable response times, the obtained evacuation times do not differ significantly between the models. In a second step, the analysis of more complex scenarios has allowed the determination of the main factors of occupant–fire interactions that cause the differences between the models: the use of unfavourable pre-evacuation times and the exit selection process under low visibility conditions. These differences occur in relation to: (1) modelling method, (2) degree of depth of the analysis of the fire conditions during the calibration of the inputs, and (3) user’s experience in applying appropriate safety factors when using only one model.

Uncertainty in Fire Protection Engineering Design

Abstract The SFPE Engineering Guide to Performance-Based Fire Protection defines “uncertainty” as “the amount by which an observed or calculated value might differ from the true value.” In engineering, there are two types of uncertainly: epistemic and aleatory. Epistemic uncertainty is uncertainty due to lack of (complete) knowledge. Aleatory uncertainty is uncertainty due to random variation. At present, no single, widely accepted methodology exists for dealing with uncertainty in fire protection engineering. This paper reviews the sources of uncertainty that are present in fire protection engineering and methods that are used to address them.

What Have We Learned About Uncertainty? Are We Still Playing with Fire?

Abstract Accurate characterization of the thermal environment in fires and fire safety tests is crucial to understanding the impact of fire on materials and assemblies and the work on modeling those impacts. Standardized fire resistance test methods have been used to help evaluate building materials and assemblies since the early 1900s and have been part of a successful effort to improve fire safety. However, current methods use predominately temperature measurements and do not provide sufficient heat transfer data to support the development and validation of fire protection engineering models. This paper looks at measurement techniques that were used successfully in pool fire research and how they could be applied to modeling structure fires.

DEVELOPING PARTNERSHIPS WITH THE FIRE SERVICE TO ENHANCE FIRE PROTECTION ENGINEERING EDUCATION OPPORTUNITIES

Fire protection engineering is increasing in importance in Canada and other countries, especially with recent changes to building and fire codes. Fire protection engineering design is highly interdisciplinary, which can present challenges when developing courses in this area. At the University of Saskatchewan, this challenge has been partially addressed through partnerships with the fire service, and other universities and research organizations. This paper discusses the importance of considering the fire service in the design process, and provides examples of partnerships with the fire service in the Mechanical Engineering undergraduate program and in graduate research projects.

Compartment Fire Temperatures

The temperature of the hot gases during a compartment fire is important to practitioners of fire protection engineering. The classic MQH correlation provides a simple and quick estimate of this temperature. An alternate model for compartment fire temperature is proposed based on an energy balance and an empirical mass flow rate formula. This model accounts for highly insulated boundary conditions and is valid for higher (>600°C) temperatures, which are two major limitations with the MQH correlation. The transition of a compartment fire to a ventilation-limited state is then analyzed to find the maximum gas temperatures. The analysis provides the maximum temperature possible for a design fire with two important variables — vent size and thermal properties of the wall material. The effects of these two variables are investigated by assuming commonly specified wall materials and different vent sizes, thereby showing the applicability of this approach for fire engineering.

Risk‐informed performance‐based approach to building regulation

Performance‐based building codes are being developed and promulgated around the world. Concurrently, performance‐based analysis and design approaches are being used in a number of disciplines, including structural, mechanical, and fire protection engineering. The performance‐based building regulatory and design environment promises great opportunities for engineers and designers to innovate and to apply analytical tools and methods to design safe, efficient, cost‐effective, and aesthetically pleasing buildings. However, for regulators and enforcement officials, performance‐based approaches are often met with skepticism and concern, as the desired performance is not always well defined and agreed, the perceived certainty associated with compliance with prescriptive design requirements is no longer assured, and there is concern that the data, tools, and methods – necessary to assure that performance‐based designed buildings achieve the levels of performance and risk deemed tolerable to society – are lacking. To address these concerns, risk‐informed performance‐based approaches are being explored, with the aim to better identify and connect tolerable levels of risk, performance expectations, and design criteria for different aspects of building design. Risk‐informed performance‐based approaches being considered in Australia, New Zealand, and the USA are discussed.