Performance-based Fire Engineering Research Articles

Quantitative assessment of the extent of damage to timber structures during the full course of a real fire using the energy equivalence method

In this study, an innovative method, the Energy Equivalence Method (EEM), is proposed in the context of the Performance-Based Fire Engineering (PBFE) framework for quantitatively assessing the degree of damage of timber structures during the full process of a real fire. To verify the validity of the method, glued laminated timber (GLT) specimens and GLT columns were selected as the subjects of fire action, and a series of equivalent fire experiments were conducted by using a parametric fire model (referred to as the DNI fire model), which is currently used in Germany, to simulate real fire scenarios. By comparing the equivalence of charring depth (CD), pyrolysis zone temperature, and residual load-carrying capacity of the test specimens after the action of the DNI fire and its equivalent standard fire, the validity of the EEM in quantifying the degree of damage to timber members after the DNI fire was fully verified. Subsequently, based on the fire experimental data, accurate thermal and structural models were developed, and these models were utilized to further validate the effectiveness of the EEM in quantifying the extent of damage to timber members under the action of a DNI fire over an arbitrary time period. The results of the study show that the proposed EEM not only can be used to assess the extent of structural damage during fire action and the residual load carrying capacity of the structure after fire action, but also promotes the transition from standard fire safety design to the PBFE design.

An open-source software framework for the integrated simulation of structures in fire

The traditional methods to understand the development of elevated temperature in a structure, and also the associated structural response, are not representative of realistic fire scenarios. To provide a more accurate and realistic reflection of the fire development, the current paper develops a generic middleware which interfaces between the computational fluid dynamics (CFD) software Fire Dynamics Simulator (FDS) and the finite element (FE) analysis software OpenSees. This framework enables a fully integrated simulation of a realistic fire scenario including the heat transfer through the structure and the resulting thermo-mechanical response. The proposed framework is open-source and freely available and therefore can be used and further developed by researchers and practicing engineers and customised to their requirements. This paper shows validation against two sets of experimental results and one real fire incident. A number of different types of thermal boundary conditions such as gas temperatures and heat fluxes, are obtained from the CFD analysis and are then used in the subsequent heat transfer and thermo-mechanical analysis. The primary advantage of this computational tool is that it provides consultants and designers with the means to undertake large-scale projects requiring performance-based fire engineering solutions.

Machine learning driven smart fire safety design of false ceiling and emergency response

In modern buildings, false ceilings are widely used for building services systems and aesthetic purposes, but they also pose challenges in terms of fire safety. A fire accident typically results from the failure of multiple safety measures or components. In many fire accidents, fire and smoke reached the false ceiling and kept spreading in the interstitial space without any detection. This study first generates a numerical database of false ceiling fire scenarios by varying the room dimensions, false-ceiling leakage area, fire size and locations. Then, a smart model based on machine learning to predict the fire smoke motion below and above the false ceiling is developed. The trained model is capable to predict the activation time of fire detectors and sprinklers for any given false ceiling design and fire scenario. This methodology enables a designer to generate multiple fire scenarios and determine the available safe egress time (ASET) for performance-based fire engineering designs especially in terms of fire detection time. In case of a real fire, with the data feed from the fire sensor network, the trained machine learning model can further predict the critical building fire events with the false ceiling, such as multi-compartment fires, smoke in the evacuation path, and structural failures. This work proposes a smart framework for improving the building fire safety design of false ceilings and the sensor-driven fire forecast to support firefighting.It enhances the emergency response processes by enabling dynamic risk assessment through prediction of critical events.

Performance-Based Structural Fire Engineering of Steel Building Structures: Traveling Fires

Many studies and observations of large building fires show that in large compartments, fires do not burn uniformly. Rather, fires will burn locally and move across a floor plate as fuel is consumed. Currently fire engineering practice assumes uniformly burning fires within a compartment and the fire design methodologies are based upon small compartment fire scenarios. Traveling fire modeling that accounts for fire dynamics is essential for performance-based fire engineering. This paper reviews two traveling fire models presented in literature and implements both models on a steel-frame building. An advanced analysis of the building is performed and the fire performance of the building in these travel fire scenarios are compared to the fire performance of the building when subjected to conventional fire exposure scenarios (full story fires or compartment fires). The authors then illustrate the use of structural fire engineering methodologies to improve the fire resistance of the building.

Steel Structures Research Update: Structural Fire Engineering

Across the United States, researchers are making exciting discoveries and advances in structural fire engineering. Eleven of the leading scholars in the field are featured. Brief research highlights are organized by the topic areas of behavior and design of steel and composite structures for fire, fire following earthquakes, and performance-based fire engineering. For each individual, related steel and fire research is also noted. Meanwhile, due to timing and circumstances, there are structural fire engineering researchers who do not appear in this article. You may find some of their structural steel research in past articles or perhaps a future research update.

Recommendations for performance-based fire design of composite steel buildings using computational analysis

Adoption of performance-based approaches in structural fire engineering is now largely recognized as having the potential to deliver benefits in terms of safety, resilience, sustainability and cost for the built environment. However, there is no systematic design guidelines for defining performance objectives, design fire scenarios, and methods of analysis. This paper focuses on steel framed buildings with composite floor slabs and provides an in-depth analysis of the structure under fire using performance-based fire engineering supported by computational modeling. First, a set of performance objectives and associated fire scenarios are defined. The scenarios include single- and multi-compartment fires as well as fire as a secondary event following a column loss. Then, response of the structure and effects of design changes are studied using different modeling approaches. Single slab, single slab with restraint, and full building models are investigated to understand the influence of continuity in the boundary conditions notably on the development of tensile membrane action. The full building model exhibited the most favorable behavior, while the single panel model without horizontal restraint was the most conservative. Best practices for computational modeling of a steel framed building under fire are discussed and recommendations are provided. The paper demonstrates an iterative design procedure, where systematic design changes are introduced to address the observed failure modes. It is shown that performance-based fire design can harness advanced computational models to examine the fire-structure behavior for multiple design alternatives and hazard scenarios.

Performance-Based Fire Engineering Design of a Heritage Building: McDougall House Case Study

The application of a performance-based fire engineering design has enabled the conservation of a heritage building in New Zealand. McDougall House is a two-story heritage building which suffered extensive damages during the Canterbury earthquakes in 2010 and 2011. The scope of the conservation plan included the preservation and restoration of the building external façade, the restoration of the ornamental plasterwork ceiling within the Ballroom, the reconstruction of all damaged internal lath and plaster linings, the adaptation of the fireplace, and the reconstruction of the damaged chimney. The fire engineering design adopted is the Verification Method C/VM2 with As Nearly As is Reasonably Practicable consideration for the heritage fabrics of the building. The combination of quantitative and qualitative analyses has demonstrated the building design compliance with the 10 design scenarios of C/VM2. These analyses include the assessment of minimum means of escape and fire protection provisions, the assessment of allowable unprotected areas in the external wall for horizontal fire spread, the assessment of firefighting provisions, the smoke and egress modelling of proposed design fires, and the benefit versus sacrifice analysis on the heritage fabrics. The application of C/VM2 results in an upgrade to the fire safety and fire protection systems of the building while also retaining and enhancing its heritage value.

Performance of parking steel column damaged by fire

PurposeThe primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading.Design/methodology/approachIn this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions.FindingsThe result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states.Originality/valueThis study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.

Development of objective-criteria-scenario triplets and design fires for performance-based Fire Safety Design

Detailed guidance for conducting performance-based fire engineering analyses for the built environment is lacking, in particular for how to identify and specify performance-criteria, fire scenarios and design fires. To help fill this gap, a method is proposed for establishing sets of ‘objective-criteria-scenario’ triplets and design-basis fires for different building-occupant systems, which can be used in regulation or directly by engineers. Application of the method forces the user to identify fire safety objectives for specific targets within a building, measurable performance criteria related to the targets and the objectives, detailed fire scenarios, and representative design fire curves, which are used to assess the building fire safety systems performance in meeting fire safety objectives. The method is briefly overviewed and particular emphasis is given to how historical data and experimental fire test data can be used to develop scenarios and associated design fire curves.

Review: development of performance-based fire design for cold-formed steel

Performance-based fire design for cold-formed steel systems is in its infancy. This paper brings together existing research on cold-formed steel materials, members, and assemblages at elevated temperatures; and complementary analysis and design methods necessary for the development of analysis-based design for cold-formed steel systems under fire. Cold-formed steel systems have become popular in building construction as both load-bearing and non-load-bearing elements, primarily due to their high strength-to-weight ratio and ease of construction. Consequently, design specifications, and structural analysis tools have rapidly evolved to facilitate engineering design of these complex thin-walled members. However, in fires the performance of cold-formed steel systems are assured by prescriptive detailing and standardized testing. Today, engineering knowledge is rapidly advancing, providing the opportunity to contemplate analysis-based design as an enabling tool for general performance-based fire engineering of cold-formed steel systems. The review provided here includes experimental results on mechanical and thermal properties of cold-formed steel and temperature dependent constitutive relations, subsystem testing and computational simulations, and analysis models and exploratory methods for fire design, i.e., the building blocks towards performance-based fire design for cold-formed steel systems.

An application of the PEER performance based earthquake engineering framework to structures in fire

The Pacific Earthquake Engineering Research (PEER) Center’s Performance Based Earthquake Engineering (PBEE) framework is well documented. The framework is a linear methodology which is based upon obtaining in turn output from each of the following analyses: hazard analysis; structural analysis; loss analysis, and finally decision making based on variables of interest, such as downtime or cost to repair. The strength of the framework is in its linearity, its clear flexibility and in the consideration of uncertainty at every stage of the analysis. The framework has potential applications to other forms of extreme loading; however in order for this to be achieved the ‘mapping’ of the framework to the analysis of structures for other loading situations must be successful.This paper illustrates one such ‘mapping’ of the framework for Performance Based Fire Engineering (PBFE) of structures. Using a combination of simple analytical techniques and codified methods as well as random sampling techniques to develop a range of response records, the PEER framework is followed to illustrate its application to structural fire engineering. The end result is a successful application of the earthquake framework to fire which highlights both the assumptions which are inherent in the performance based design framework as well as subjects of future research which will allow more confidence in the design of structures for fire using performance based techniques.This article describes the PEER framework applied to structural earthquake design then follows the framework from start to completion applying suitable alternative tools to perform each stage of the analysis for structures in fire.

A fire resistance design method for thin-walled steel studs in wall panel constructions exposed to parametric fires

This paper investigates the applicability of a simple fire resistance design method for axially loaded thin-walled steel studs in wall panel assemblies when exposed to parametric fires from one side. The simple method includes calculations of cross-section temperatures and ultimate load carrying capacities at elevated temperatures. The simplified calculation method for heat transfer in the cross-section is based on dividing the cross-section into a number of segments. The thermal properties of these layers are based on weighted averages of the thermal properties of the components contained within. The structural capacity calculation method is based on the Direct Strength Method. Results from the design method are compared with the results from Finite Element simulations for heat transfer and structural analysis (236 models). The calculation results are in good agreement with the simulation results and the proposed method may be used in performance-based fire engineering design of such construction.

Using business impact analyses to enhance resilient fire engineering building design

As an engineering discipline within the United Kingdom, fire engineering is relatively young. It has been accepted as an alternative to traditional prescriptive means of meeting the functional requirements of the building regulations since the publication of the 1985 edition of Approved Document B. Performance-based fire engineering design methods have facilitated architectural design freedoms and supported creative construction. However, it has become evident that since fire engineering has become more established, significant concerns have been raised regarding various elements of the design process including the ability to consider aspects other than life safety. In response to these concerns, this article introduces novel application of concepts to assist the building design team to consider their client's resilience requirements. This is by utilising business continuity planning methods, specifically business impact analyses within the fire engineering qualitative design review. By using these concepts in this new way, the architectural design team will be able to identify those processes which are of greatest importance to their client's organisation, allowing the most appropriate fire engineering strategy to be established.

New Zealand fire Service Response Times to Structure Fires

New Zealand's Building Code has recently been amended and has introduced a new clause specific to fire-fighting operations that requires, amongst other things, that buildings must be designed and constructed to allow fire-fighters to reach the floor of fire origin and search the general area. The Code also specifies that for certain buildings they must be designed and constructed to allow fire-fighters to be able to first apply water to the fire before specified tenability criteria have been exceeded. These new requirements and other established performance-based fire engineering methods require the times associated with various fire brigade intervention tasks and specifically arrival times to be quantified.Currently there is limited data available to allow specific calculation of fire service response times to buildings. This paper presents response time and travel speed distributions to enable calculation of the time taken for the fire service to respond to notification of a fire and arrive at a specific location. Comparisons between response times within urban and rural fire districts are presented and between three of New Zealand's largest cities, their central business districts and outer suburbs. Distributions are presented and compared to existing values suggested by the Fire Brigade Intervention Model with data given to allow the assessment of the probability of attendance.

The Role of Connections in the Response of Steel Frames to Fire

Connections are critical structural elements of building frames, and in a fire are subject to forces very different from those at the ambient temperature for which they are designed. The fracture of a connection can cause the collapse of the connected beam, which may lead to a progressive collapse sequence affecting the entire building. This paper overviews the sequence of research on connection behaviour in a fire at the University of Sheffield. Early work focused on studying connections in terms of their moment–rotation behaviour alone. Concurrent full-scale building fire tests led to the realization that the tying capacity of connections is of prime importance for maintaining the structural stability in a fire. For whole-structure numerical modelling in performance-based fire engineering design, the development of the component-based approach, which was initially introduced for ambient temperature connection design, is an appropriate way to rationalize and model connection behaviour under these complex loadings. The effect of high co-existent rotation on the tying capacity of connections has been studied in furnace tests at various temperatures, which have provided data to assist in the characterization of the component-based model. A general component-based connection element, into which appropriate component models can be inserted, has been developed so that full connection performance, including fracture of components, can be integrated into global non-linear structural fire analysis. This will allow buildings to be modelled for a range of fire scenarios so that they can be designed to avoid progressive collapse in a fire.

Ensuring Resilience in Building Design Using Fire Engineering

As an engineering discipline within the United Kingdom, fire engineering is relatively young. It has been accepted as an alternative to traditional prescriptive means of meeting the functional requirements of the Building Regulations since the publication of the 1985 edition of Approved Document B. Performance-based fire engineering design methods have facilitated architectural design freedoms and supported creative construction. However, it has become evident that since fire engineering has become more established, significant concerns have been raised regarding various elements of the design process including the ability to consider aspects other than life safety which may result in a poorer overall response of the building to fire, while achieving the life safety ambition. In response to these concerns, this article introduces novel concepts to assist the building design team consider their client's resilience requirements by utilizing business continuity planning methods. Using business impact analyses within the qualitative design review will identify those processes which are allowing the most appropriate fire engineering strategy to be established. This new approach to fire engineering design is to be formally described within a new part of the established British Standard which defines a fire engineering procedure.

Performance Based Fire Engineering Research of Steel and Composite Structures: A Review of Joint Behaviour

Joints are critical members of a structure at both ambient temperature and in fire. Under fire conditions, joint behaviour has crucial influence on control of fire induced progressive collapse of the structure. Joint behaviour in fire is also considerably more complex than that at ambient temperature, because the joint forces change at elevated temperatures in fire. This paper will present a review of some recent research studies on steel joint behaviour under fire conditions. These studies include temperatures in different components of different types of joint, mechanical behaviour of different joint components, experimental study and numerical modelling of joint behaviour, either as an individual joint or as part of a structure. Afterwards, this paper will present some results of the influence of joint behaviour on structural fire behaviour. Compared with other aspects of steel structural fire behaviour, research on joint behaviour in fire is relatively recent so comprehensive design guides are not yet available. Nevertheless, it is possible to provide some guidance on potential joint influence on improving steel structural fire resistance or reducing the risk of fire-induced progressive structural collapse.

Survey on passenger loading in the Hong Kong airport terminal

Emergency evacuation is the main concern in crowded airport terminals. Data on occupant loading are important for designing means of escape. However, very few field survey data on crowded terminals are available in the literature. There are queries concerning whether the data specified in the prescriptive codes are realistic in designing safety systems in modern terminals. More questions have been raised for those terminals using data, such as maximum floor area allowances per occupant, from the prescriptive codes which have not yet been verified for carrying out performance-based fire engineering design. In this study, passenger loading in the Hong Kong airport terminal was investigated. A field survey was carried out, in which the performance-based design was based on the occupant loading factor extracted from the prescriptive codes of Hong Kong. Transient passenger loadings of the airport in different seasons were compiled. The results were used to justify the maximum allowed loadings specified in design codes and standards.

Integrated network approach of evacuation simulation for large complex buildings

Abstract Safe evacuation is the most fundamental requirement of fire safety measures in buildings. Traditional building evacuation design is governed by prescriptive building codes which neither have a clear statement of design objectives, nor proper consideration of the interactions between different components of the evacuation system. With rapid developments in performance-based fire engineering, computer evacuation models have been widely used by fire engineers and government officials in fire safety design of buildings. Two approaches are usually used to represent the buildings in evacuation models: fine and coarse networks [Gwynne et al., A review of the methodologies used in the computer simulation of evacuation from the built environment, Building and Environment 34 (1999) 741–749]. For large and complex buildings, such as high-rise or assembly buildings, owing to their spatio-temporal complexity, neither of the 2 network approaches in isolation is satisfactory. The fine network model requires extensive computational power while the coarse network model may not be adequate in representing details of the evacuation process. This paper presents an approach that integrates both network approaches for efficient and detailed assessment of evacuation in large and complex buildings. To demonstrate the advantages of using the integrated approach, this paper presents the results of evacuation simulation for 2 representative buildings. It has been found that the fine network approach (FNA) is inadequate to simulate evacuation of large complex buildings on a normal PC in terms of computational resources. In contrast, the integrated approach can not only perform evacuation analysis for the whole building but is also able to give detailed movement pattern in places of interest without consuming a large amount of CPU time, which makes it possible to directly identify the potential “bottlenecks” in the building.

An Investigation on the Building Officials' Perception for the Use of Performance-Based Fire Engineering Approach in Building Design

Traditionally, the spatial design of a building is influenced by the prescriptive fire safety codes. As buildings develop and become more complex and new materials are used, the prescriptive fire safety rules may not provide an efficient solution to the new building design. A system approach to the design of fire safety in buildings on the basis of performance criteria may be necessary. The recently published fire codes in Hong Kong have recognized the use of a performance-based fire safety engineering approach as a means to demonstrate the adequacy of fire safety design in a building. However, the judgement on the adequacy is made by the building control officials. Whether they believe the use of such a performance-based fire safety engineering approach can provide adequate fire safety level in a building can have influence on promoting performance-based design. This paper discusses the Hong Kong system and a survey on the views of the building control officials. The investigation indicates that the officials, in general, agree with the need of using performance-based approach, in particular to keep pace with the advancement of building technology. However, they have reservations on the adequacy of current tools for fire safety engineering design. Such views are in line with that of the building officials in the United States.