Search

The traditional storage method of fire accident cases is mainly in the form of text, and it is difficult to effectively conduct comprehensive analysis due to the limited ability to display key information and fire knowledge. In this paper, a structured storage form of building fire cases was proposed based on knowledge graph, which can comprehensively describe and visualize the fire causes, the dynamic fire development process and evacuation process. It enables readers to get information and knowledge from building fire cases intuitively, and supports the comprehensive analysis for building fire prevention strategies. The knowledge graphs are constructed for two common building types (residential and public buildings), and have the capacity to reflect the dynamic development law of fires from ignition to spread in different buildings. Meanwhile, as the occupants' evacuation is the first concern when a fire occurs, the knowledge graphs also visualize the relationship among various conditions in the evacuation process. Different application scenarios are displayed in the paper, including case query, root-cause analysis and consequence forecasting, which shows the advantages and applicability of building fire knowledge graph. [ABSTRACT FROM AUTHOR]

One of the significant hazards in the event of a fire in high-rise residential buildings in cities is the length of time taken to completely evacuate a large number of occupants. On a city scale, it is important that a city's fire and rescue services are in place to minimize the consequences which can be incurred in any potential fire incident. The paper presents the methodology and results of a study that evaluates the city-wide vulnerability in high-rise residential building fires in the City of Istanbul, Turkey. In the context of fire and rescue service arrival to burning buildings, a high-rise building can be considered vulnerable if the fire and rescue service arrives at the building site only after the expected completion of evacuation of the building, thus unable to fulfill its intended purpose of saving the occupants. The study is based on comparison of an agent-based evacuation model of safe escape times for 1167 high-rise residential buildings against their fire and rescue service arrival times estimated using GPS data. This methodology can be used to inform the decision about optimal locations of a city's fire and rescue services. As an example, this study indicates that adding a single new fire station in the City of Istanbul can improve its preparedness for fire accidents by reducing the risk of its most vulnerable district by more than 26%. [ABSTRACT FROM AUTHOR]

To date there is no International standard on the verification and validation (V&V) of building fire evacuation models, i.e., model testers adopt inconsistent procedures or tests designed for other model uses. For instance, the tests presented within the MSC/Circ.1238 Guidelines for evacuation analysis for new and existing passenger ships provided by the International Maritime Organization are often employed for the V&V of models outside their original context of use (building fires instead of maritime applications). This paper presents a list of verification tests for component testing and the analysis of emergent behaviours together with examples of experimental data-sets suitable for the analysis of different core components. The capabilities of building fire evacuation models are evaluated by studying their five main core components, namely (1) pre-evacuation time, (2) movement and navigation, (3) exit usage, (4) route availability and (5) flow constraints. This paper discusses the tests which are included in a freely available Technical Note developed at the National Institute of Standards and Technology. This work is intended to open a discussion on the main issues associated with the definition of a standard procedure for the V&V of building fire evacuation models, including the definition of the acceptance criteria of a standard V&V protocol. [ABSTRACT FROM AUTHOR]

This scoping review addresses the role of functional limitations on evacuation performance of adults in public buildings. Although this topic has been addressed in evacuation research, no linkage is currently available between functional limitations, the predominant activities affected by them and evacuation performance. This review strives to open a debate on the need to classify the impact of disability in terms of functional limitations on evacuation performance according to methods adopted in health science. This paper reviews literature concerning evacuation from public buildings with adults aged ≥ 60 years and/or adults aged ≥ 18 years with functional limitations. The International Classification of Functioning, Disability and Health has been used to identify predominant activities during an evacuation and to perform a structured classification at different levels of resolution to address self-evacuation possibilities. Results of the review are presented in a tabular form linking predominant activities in terms of the International Classification of Functioning, Disability and Health and six categories of functional limitations with the engineering evacuation time-line. The suggested classification can facilitate the assessment of the evacuation-related issues in buildings in relation to the population under consideration. The main research gaps identified include the lack of studies concerning the impact of cognitive limitations on egress, and the need to add the temporal dimension to the methods adopted in accessibility research to allow for their use in the egress field. [ABSTRACT FROM AUTHOR]

Probabilistic analysis is receiving increased attention from fire engineers, assessment bodies and researchers. It is however often unclear which probabilistic models are appropriate for the analysis. For example, in probabilistic structural fire engineering, the models used to describe the permanent and live loads differ widely between studies. Through a literature review, it is observed that these diverging load models are based on surveys conducted between 1893 and 1976 and that widely adopted assumptions, such as the rule for combining permanent and live loads into the total load effect, are commonly adopted based on precedent. The diverging current models however relate to mostly the same underlying datasets and basic methodologies. Differences can be attributed (largely) to specific assumptions in different background papers, which have become consolidated through repeated use in research papers and adoption in background documents to codes. By reviewing the studies underlying currently applied probabilistic load models in structural fire engineering, a consolidated probabilistic load model is proposed in this paper. It is concluded that the total load effect is ideally described by KE·(G + Q), with KE the model uncertainty for the load effect, G the permanent load, and Q the imposed load. The model uncertainty KE can be described by a lognormal distribution with mean equal to unity and coefficient of variation (COV) of 0.10. The permanent load is preferably modelled by a normal distribution with mean equal to the nominal permanent load, and a COV which can either be assessed on a project specific basis, or can be set to 0.10 for a first assessment. For common occupancies (office, residential), the live load is preferably modelled by a Gamma distribution. The mean live load can be taken as 0.2 times the nominal, and the live load COV can be taken as 0.60 for large load areas (> 200 m2) and 0.95 for smaller load areas (< 100 m2). Comparison between the failure probabilities of steel and concrete columns subject to fire, considering the proposed consolidated model and two currently commonly used models, indicates that relative differences of the probability of failure can be in the order of 10%. Live load models for evacuation routes and warehouses require specific study and are outside the scope of the review. [ABSTRACT FROM AUTHOR]

Numerous evacuation performance data for the utilization in evacuation modelling and simulations have been established for the conventional/widely studied scenarios, such as building evacuation scenarios. However, such data are typically scarce for a new scenario in literature — evacuation from high-deck coaches. This paper fulfills this gap by presenting empirical high-deck coach evacuation data-sets that can be used for model configuration and validation. To this end, firstly, five essential and commonly used performance metrics, i.e., evacuation time, flow rate, alighting time gap, velocity on stairways and exit choice, were collected and derived from two series of controlled experiments with 7 and 22 runs that involved 44 and 96 participants respectively. Then, all these datasets were structured in the distribution form, based on which three critical behavioural insights are revealed regardless of the evacuation conditions (the types of high-deck coaches, lighting conditions, and age groups). First, the evacuation behaviour in normal (experimental) conditions conforms to a multi-stage pattern (a modified four-stage pattern, i.e., reaction, acceleration, fluctuation and saturation stages). Second, the instantaneous flow rate can be well captured by the Burr, Loglogistic and Lognormal distributions, and the alighting time gap can be represented by the Burr distribution. Third, more than 50% of passengers evacuate through the rear door in the front-and-rear-door evacuations. The frequency of choosing the front door is found to shift towards the direction of the rear door compared to the ideal results (based on the shortest distance calculation) with a magnitude of approximately 1.95 seat rows. The presented data-sets are valuable resources for the development of high-deck coach evacuation models. The empirical findings promote the understanding upon the evacuation behaviour of high-deck coach passengers. [ABSTRACT FROM AUTHOR]

In order to provide a reliable evacuation design assessment, data showing the variation in pre-movement time is of vital importance. The pre-movement time is in many cases regarded as the main time period during an evacuation assessment. Therefore, forty unannounced evacuation experiments for six different occupancies were analysed to quantify pre-movement time during building evacuation, i.e., the time taken between receiving the first cue and initiation of movement towards an exit during evacuation. The occupancies were office, cinema theatres, restaurants, department stores and night clubs. The occupancies were equipped with different types of evacuation alarm systems. The study resulted in 2486 data points for the pre-movement time. The pre-movement times were matched to statistical distributions to describe the variation. It was found that the pre-movement times in most cases could be represented with a lognormal or loglogistic distribution typically having a rapid initial increase representing the phase when people start reacting, which is followed by a less steep decrease representing the phase when some people linger before evacuating. Most reliable data are provided for the cinema theatre experiments which included 1954 data points from 30 experiments. The paper also presents a structure for performing an assessment of video recorded evacuation experiment determining actions, relevant time data and fitting a statistical distribution to the data. The new information provided in the paper can help fire safety professionals to more accurately predict the time to evacuate different premises. [ABSTRACT FROM AUTHOR]

In modelling human behavior during a fire, one has to deal with uncertainties regarding the psychological response due to limited or incomplete knowledge database. The purpose of this paper is to develop a new fuzzy Bayesian Network framework to model causal relationship of psychological response at the initial stage of fire events. Firstly, a new conceptual model namely the PRiF (Psychological Response in a Fire) is developed through the literature of human behaviour in fire evacuation modelling and expert opinion approach. Then, the expert elicitation using fuzzy linguistic concept was adapted in quantifying the PRiF model. Finally, an example of expert elicitation study is demonstrated to illustrate the practical application of the proposed methodology. Results show that the proposed methodology is not only able to capture the sequence of psychological reactions in line with the theory of human behavior in a fire but also can quantitatively measure the likelihood of circumstances of possible undesired scenario, and identify the most influential factors or prioritize the root causes of unsuccessful safe evacuation. [ABSTRACT FROM AUTHOR]

Fire in buildings pose a significant threat to occupants, first responders as well as the structural system. Rapid spread of fire and smoke in buildings can hinder the process of evacuation resulting in loss of human life. Such situations call for a reliable egress system that provides safe evacuation of occupants in minimal time. Updating the occupants and first responders with much-needed situational awareness such as accessible stairwells and exits during the disaster can not only lead to efficient evacuation but also shorten the duration of evacuation in some scenarios. This paper examines occupant evacuation scenarios in fire exposed high-rise buildings. A parametric study is carried out on evacuation strategies in a 32-story typical office building during different fire exposure scenarios. The movement of occupants with and without situational awareness is simulated. The effect of critical parameters such as number of stories, width of the egress paths, location and number of exits on the evacuation process is evaluated. The time required for occupants to evacuate the building is estimated under normal conditions (to simulate fire evacuation drill) and under realistic fire exposure. Results from the study indicate that the two most significant factors that influence evacuation time are the location of stairway within the building and the floors at which fire starts. When fire starts at the lower levels of the building, the evacuation time is the highest. More importantly, if situational awareness is incorporated in emergency evacuation procedure, it can improve the evacuation efficiency in a fire exposed high-rise building; wherein up to 24% reduction in evacuation time is achieved. [ABSTRACT FROM AUTHOR]

How do evacuees behave and what factors influence their egress selection behavior of stairs or an elevator during a high-rise building evacuation? These issues remain unclear given a paucity of research. In this paper, a series of experiments and questionnaires with 45 participants were carried out to examine the effects of non-irritant smoke and participants' knowledge of evacuation procedures (especially elevator evacuation). After each experiment, participants were asked to respond to a questionnaire. The results of evacuation times for the elevator versus stairs, the proportion of elevator users, elevator wait times, and redirect behaviors are analyzed and discussed. In experiment 1, 26.7% of 45 participants chose the elevator. In experiment 2, non-irritant smoke was released, and the proportion of participants who used the elevator decreased to 24.4% of 45 participants. Before experiment 3, we shared information about the evacuation (i.e., an explanation of evacuation procedures and elevator evacuation experience) with the participants, after which elevator use increased to 40% of 45 participants. As a result, we found that non-irritant smoke and knowledge of evacuations affected evacuees' behavior; however, the gap between the proportions of participants who reportedly preferred to use the elevator and who actually used the elevator was large. According to the questionnaire, the proportion of participants who wanted to use the elevator was 55.6%. Moreover, elevator overload, physical fatigue, and social bonds were observed in our experiments. In conclusion, several suggestions are given to building designers, and basic data (such as evacuation times and proportion of stairs or elevator use) offer insight for building safety engineers in designing evacuation strategies incorporating stairs and elevators. [ABSTRACT FROM AUTHOR]

During a fire evacuation, once an individual perceives cues from a fire event, they must interpret them to assess the new situation and determine whether action is required. It is proposed that this assessment and action selection can employ either an automatic or reflective processing system depending on the nature of the situation and the experiences of the individual involved. This decision-making process is bounded in terms of the information available, the time available, and an individual's resources to process such information that influences which processing mechanism is adopted. To compensate for such limitations and manage the uncertainty and complexity associated with the decision-making process, people may employ heuristics that reduce decision-making from a cognitively effortful problem-solving task requiring mental reflection, to a less effortful pattern-matching process, where stored conditions and expectations are quickly scanned to identify relevant responses. During this decision-making process cognitive biases may occur which cause an individual to neglect or be biased towards certain information: this may potentially lead to an inappropriate and/or unexpected response. Cognitive biases affect performance without the individual being directly aware of them. This paper identifies cognitive biases from existing literature that may influence a person's decision-making process during a fire evacuation, along with how these align with general decision-making in the process. The purpose of the article is to promote consideration of cognitive biases in the modeling of evacuee behavior, as well as during the fire safety design of buildings and evacuation procedures. [ABSTRACT FROM AUTHOR]

Following the attacks on the World Trade Center in New York City on September 11, 2001, several large studies were undertaken to look at the evacuation. The studies began from 18 months to 4 years after the event, and although there were similarities in the data sets collected in these studies, each set out to answer or contribute to a somewhat different purpose-investigation into the collapse of the towers, emergency preparedness in the workplace, and enhancements in the computer simulation of the evacuation of high-rise buildings. The studies used a variety of data collection techniques. This paper briefly describes the studies, their study populations, summary findings and long-term impacts. [ABSTRACT FROM AUTHOR]

Evacuation models, including engineering hand calculations and computational tools, are used to calculate the time it takes to evacuate a building, which can then be used in an engineering safety analysis. However, there is a lack of available data and theory on occupant behavior for use by evacuation models to estimate evacuation time results and their uncertainty. In lieu of data and theory, evacuation models (and users) make assumptions and simplifications about occupant behavior, which can inappropriately characterize the time it actually takes to evacuate a building. The purpose of this paper is to reevaluate current egress modeling techniques and advocate for the inclusion of a robust, comprehensive, and validated conceptual model of occupant behavior during building fires. This paper begins by describing the current state of evacuation modeling of human behavior in fires and identifying gaps in current behavioral prediction techniques. The second part of the paper outlines a model of occupant decision-making during emergencies, referred to as the protective action decision model (PADM); a theory that can serve as the basis for the development of a conceptual model of occupant decision-making and behavior during the pre-evacuation period of building fires. The PADM provides a framework that describes the decision-making steps that influence protective actions taken in response to natural and technological disasters-including perceiving information, paying attention to the information, comprehending the information, establishing the nature of the threat, personalizing the risk, searching for potential protective actions and choosing one of these, and then performing that action. The paper ends with a discussion of how to adapt and expand the PADM in order to develop a predictive conceptual model of the pre-evacuation period for use by computer evacuation models. [ABSTRACT FROM AUTHOR]

This paper promotes a discussion about evacuation models and their relation with evacuation processes. For this reason, the question “quo vadimus” (i.e., from Latin: where are we going to?) intends to initiate this discussion. Therefore, a brief overview of the importance of the evacuation modelling analysis within the Fire Safety Engineering (FSE) context is presented. This paper also presents an analysis of the evacuation modelling process and some remarks on how the evacuation models' reviews are being done as well. Furthermore, along with the previous question, some other subsequent key-questions can be aroused and this paper intends to analyse them, namely: Do we need the evacuation models for understanding evacuation processes? Are we doing the evacuation models' reviews properly? Do we understand well the evacuation models? Do we understand the evacuation modelling process? [ABSTRACT FROM AUTHOR]

This paper presents an overview of contemporary sociological issues in fire safety. The most obviously social aspects of fire safety-those that relate to the socioeconomic distribution of fire casualties and damage-are discussed first. The means that society uses to mitigate fire risks through regulation are treated next; focusing on the shift towards fire engineered solutions and the particular challenges this poses for the social distribution and communication of fire safety knowledge and expertise. Finally, the social construction of fire safety knowledge is discussed, raising questions about whether the confidence in the application of this knowledge by the full range of participants in the fire safety design and approvals process is always justified, given the specific assumptions involved in both the production of the knowledge and its extension to applications significantly removed from the original knowledge production; and the requisite competence that is therefore needed to apply this knowledge. The overarching objective is to argue that the fire safety professions ought to be more reflexive and informed about the nature of the knowledge and expertise that they develop and apply, and to suggest that fire safety scientists and engineers ought to actively collaborate with social scientists in research designed to study the way people interact with fire safety technology. [ABSTRACT FROM AUTHOR]

Evacuation simulation has the potential to be used as part of a decision support system during large-scale incidents to provide advice to incident commanders. To be viable in these applications, it is essential that the simulation can run many times faster than real time. Parallel processing is a method of reducing run times for very large computational simulations by distributing the workload amongst a number of processors. This paper presents the development of a parallel version of the rule based evacuation simulation software buildingEXODUS using domain decomposition. Four Case Studies (CS) were tested using a cluster, consisting of 10 Intel Core 2 Duo (dual core) 3.16 GHz CPUs. CS-1 involved an idealised large geometry, with 20 exits, intended to illustrate the peak computational speed up performance of the parallel implementation, the population consisted of 100,000 agents; the peak computational speedup (PCS) was 14.6 and the peak real-time speedup (PRTS) was 4.0. CS-2 was a long area with a single exit area with a population of 100,000 agents; the PCS was 13.2 and the PRTS was 17.2. CS-3 was a 50 storey high rise building with a population of 8000/16,000 agents; the PCS was 2.48/4.49 and the PRTS was 17.9/12.9. CS-4 is a large realistic urban area with 60,000/120,000 agents; the PCS was 5.3/6.89 and the PRTS was 5.31/3.0. This type of computational performance opens evacuation simulation to a range of new innovative application areas such as real-time incident support, dynamic signage in smart buildings and virtual training environments. [ABSTRACT FROM AUTHOR]

Modeling building evacuation during fire emergencies is an important issue. The social force model is a well-regarded evacuation modeling technique, and it has been integrated into the Fire Dynamics Simulator with Evacuation (FDS + Evac) of NIST to simulate building fire evacuation. However, these models still have limitations to be improved. First, occupants' movement can be unrealistically prevented. For example, the corner of doors exerts unrealistic repulsive forces on occupants, so the simulated flow at narrow doors is much smaller than experimental data. Second, the degree of occupants' competitiveness is not considered. Finally, current models are rarely validated by data form real-life emergencies, in which occupants may behave differently from normal situations. In this paper, new social forces are used to replace old ones to modify occupants' collision avoidance: both time headway and time-to-collision are viewed as indicators of potential collisions, and social forces are active if time headway or time-to-collision reaches thresholds. A parameter is used to represent how the degree of occupants' competitiveness affects their collision avoidance. The modified model is validated by both lab experiments and real emergency evacuation. First, the relation between simulated flow and door width in non-competitive situation is used for validation. In the simulation, 94 occupants, initially distributed in a 9 m - by - 4 m area, evacuate from a door. The simulated flow rates through doors of width ranging from 0.6 m to 1.2 m are consistent with the experimental data. Second, effects of competitiveness are studied. Simulation results show that whether competitiveness speeds up or slow down the evacuation through a door is affected by the initial number of occupants, door width, and other occupants outside the door. Finally, simulation results in competitive situation are consistent with data from a real-life emergency evacuation. The data used is extracted from a video recording occupants evacuating from an airport through a security gate in an earthquake. Simulation results are consistent with the real-life data in both the total evacuation time and the time when congestion occurred. [ABSTRACT FROM AUTHOR]

There are currently efforts to inform the public of the fire safety benefits of keeping bedroom doors closed when occupants are sleeping. A closed door can provide a substantial advantage to sleeping occupants of a bedroom in the event of a fire by hindering the spread of heat and toxic gases. The overall benefit in this arrangement is clear when occupants have interconnected smoke alarms inside and outside the sleeping areas as detection and notification of the fire is not hindered by a closed door. Concerns have arisen for situations when such a detection and notification arrangement is not present in the residence and the door can act as an obstacle for rapid detection and notification of occupants. Calculations and data from the fire science literature were used to evaluate the effect of a closed bedroom door on the number of unsuccessful evacuation outcomes that may result from fires originating in the bedroom, as well as the effect of a closed bedroom door on the audibility of smoke alarms for fires originating elsewhere in the residence. This was combined with statistics on smoke alarm coverage, residential fires, and fatalities to quantify the unsuccessful evacuation outcomes. These results were compared with the number of fire fatalities where a closed bedroom door could offer a benefit. Overall, it was found that the number of unsuccessful evacuation outcomes from a closed bedroom door were relatively small and that the potential benefit of closing a bedroom door was far greater. The analysis concludes that on a purely technical basis, closing the bedroom door at night will save lives and provides a net benefit to the public. [ABSTRACT FROM AUTHOR]

This paper describes the occupant evacuation of World Trade Center (WTC) 1 and WTC 2 on September 11, 2001. Multiple sources of information were collected and analyzed: over 1,000 new interviews with survivors (including 803 telephone interviews, 225 face-to-face interviews, and 6 focus groups); over 700 published interviews; 9-1-1 emergency calls; transcripts of emergency communications, historical building design drawings, memoranda, and calculations; formal complaints filed with the Occupational Safety and Health Administration; and other relevant materials. The population in WTC 1 and WTC 2 on September 11, 2001, at 8:46:30 a.m. is enumerated and described, where the characteristics of the population were relevant to the subsequent evacuation, including training, experience, mobility status, among others. The progress of the evacuation of both towers is described in a quasi-chronological manner from 8:46:30 a.m. when WTC 1 was attacked, until 10:28:22 a.m., when WTC 1 collapsed. [ABSTRACT FROM AUTHOR]

This paper provides an analysis of the evacuation of the World Trade Center towers culled from telephone and face-to-face interviews with survivors. The first investigation explored where occupants were located when each tower was attacked. Regression analysis explored the sources of variance in occupants' time to reach the stairwell, as well as stairwell evacuation time (how long the average occupant spent in the stairwells per floor). Finally, issues identified as contributing to either slowing or aiding the evacuation process were also explored. [ABSTRACT FROM AUTHOR]

During an evacuation from a building, the use of particular exits may vary significantly resulting in some becoming crowded while others are rarely used, which may cause inefficient egress. In this study, a new method of quantifying this varying exit usage and subsequently categorizing them into five different performance groups is proposed. This method is expected to allow us to compare the performance of exits in the same building as well as exits between separate buildings. To quantify the exit usage, the actual numbers of occupants using specific exits for a certain period are needed as well as the design occupant load and design number of occupants using the specific exits. The former values are obtained by actually counting occupants and the latter values are determined by exit design criteria, i.e., calculations found in building and life safety codes. Seven exits are selected from two buildings and their performance is compared quantitatively as a proof of concept. We hope these equations can be used in future research for the quantitative and qualitative study of exit usage. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the guest editor discusses various topics within the issue on topics including the evacuation of the World Trade Center on September 11, 2001, computer simulation of the evacuation, and the template for a proposed on-line database for storage of evacuation and behavioral data from experience and experiments.

The transient flow characteristics in inclined tunnel fire considerably influence occupant evacuation. We conducted brine water experiments to investigate transient smoke movement characteristics and their evolution into multiple final flow states in an inclined tunnel fire. The flow pattern exhibited a downward trend was the expected flow pattern. The experiment results indicated that before longitudinal mechanical force was activated in the inclined tunnel, the thickness of the current was nearly uniform. When longitudinal mechanical force was activated, the propagation velocity of the upstream longitudinal current declined, and then the back-layering reached its maximum length. During the naturally ventilated stage, the propagation velocity of the downstream and upstream current were approximately proportional to the cubic root of the source buoyancy flux, respectively. In the longitudinally ventilated stage, the modified Richardson number R i ′ defined as Eq. (16) were used to analyze the head propagation velocity of both the downstream and upstream currents, and then the empirical models were proposed based on the experimental data. Multiple final flow states existed even under identical longitudinal force and source buoyancy flux; distinct steady flow states were resulted from different initial conditions, that is, distinct longitudinal force activation times. If the buoyant fluid eventually evolved into the expected pattern and flowed out from the downstream end of the tunnel, the initial condition did not considerably influence the reduced gravity distribution in the final steady state.Please confirm the affiliationsI have confirmed.Please check and confirm the short title.Yes, I have checked and confirmed. [ABSTRACT FROM AUTHOR]

The modelling of common corridor smoke control systems in residential buildings is one of the most frequently undertaken performance-based assessments by fire engineers in the UK. However, there is limited understanding of how the deterministic assumptions provided in modelling guidance are derived, and to what extent these are representative of a range of possible outcomes. To place these assumptions into context, the Monte Carlo method is applied using the zone modelling software B-RISK for an exemplar residential arrangement. Distribution functions are adopted to inform inputs for fire parameters, sprinkler performance, and occupant behavioural characteristics. An output distribution for the corridor smoke clearance time is determined and compared to the clearance time of an equivalent set of deterministic simulations applying the assumptions of modelling guidance. The probabilistic study indicates that modelling guidance assumptions typically result in a scenario severity greater than the 99th percentile of possible outcomes. The work also considers the sensitivity of individual input parameters, ranking these based on their impact. These sensitivity analyses highlight the importance of occupant behavioural assumptions around the pre-evacuation time and door open time, and the significance of fire parameters including the elevation of the fuel bed, soot yield, and fire growth rate. Sprinkler parameters are shown to have a lesser impact on the corridor clearance time. The work therefore provides practitioners with an indication of which parameters are worth considering in greater detail when assessing scenario sensitivity. [ABSTRACT FROM AUTHOR]

Movement on stairs is a crucial factor that influences people's ability to evacuate from buildings in fire emergencies. In fact, the accessibility of stairs during multilevel evacuations is considered to be a criterion for the tenability of a building. Biomechanical analyses of pedestrian staircase descent add nuance by characterizing factors relevant to safe movement on stairs, such as foot placement, use of handrails, and balance. While these factors are not traditionally captured by evacuation analyses and models, their inclusion can point to areas of particular risk during evacuation from physiological, environmental, design, and engineering standpoints. This systematic review presents relevant biomechanical aspects, with a particular focus on factors that influence downward movement on stairs for evacuation purposes. The review begins with findings on walking speeds, gait analysis (e.g., cadence and foot clearance), as well as changing demographics are summarized. Then, research on balance control (vision, proprioception, and limb coordination) is presented, followed by findings on fatigue and grasping. Implications of the empirical findings are then considered for evacuation modelling, safer and more efficient evacuation procedures, as well as building design. Finally, limitations of the review itself and future research needs are explored. [ABSTRACT FROM AUTHOR]

The evacuation of the World Trade Center (WTC) Twin Towers on 9/11 is one of the largest full scale high-rise emergency evacuations to date and provides an opportunity to learn from survivor experiences. Here, quantitative and qualitative data extracted from the UK WTC High-rise Evacuation Evaluation Database (HEED) study were used to: (i) calculate more fine-grained response times useful for evacuation modelling; (ii) investigate Response Phase behaviours; and (iii) see which of these behaviours and other factors predicted the response times. Analyses revealed that the majority of participants' response times were within 0 min to 1 min of WTC1 being hit (rapid responders) and 1 min to 4 min (moderate responders). Logistic regression indicated that rapid responders were more likely to be participants in WTC2 than participants in WTC1, the tower that was currently under attack. Higher perceived risk and undertaking fewer if any tasks prior to evacuation also significantly predicted rapid response times. Conversely, response times beyond 1 min from WTC1 impact were significantly predicted only by increased numbers of Information Tasks being undertaken prior to evacuation. These tasks appeared to be undertaken more frequently prior to evacuation than were Action Tasks. [ABSTRACT FROM AUTHOR]

Past studies suggest that people are often reluctant to use occupant evacuation elevators in case of fire. However, existing research is scarce and current knowledge is based on questionnaire studies and laboratory experiments. An unannounced evacuation experiment was therefore performed on the 16th floor of a 35-floor high-rise hotel building. Sixty-seven participants took part and eye-tracking glasses were used to collect data on exit choice and eye fixations. Three different scenarios were studied, including two different hotel room locations on the floor and a variation of guidance system for one of these locations, i.e., flashing green lights next to the evacuation sign at the elevators. Results suggest that people typically choose the elevator for evacuation, even if their hotel room was located closer to the evacuation stair. Flashing green lights next to an evacuation sign made people look more at this sign. However, in spite of looking more at the sign, the flashing light was not shown to significantly improve compliance with the sign. Also, the results suggest that a detector activated self-closing fire door without vision panels to the elevator lobby made it more difficult to find the evacuation elevators in an emergency. [ABSTRACT FROM AUTHOR]

Smoke alarms are relied upon to notify building occupants of a fire, and the performance of these devices in the fire environment is critical for the safe evacuation of the building occupants. Development of smoke detection technology has focused primarily on the activation time of the smoke alarm and the amount of escape time they will provide. The growth rate of fires in industrial and residential settings has increased significantly in the past four decades, often attributed to the construction and materials of modern-day furnishings and contents compared to that in the 1970s. This changes the thermal environment smoke alarms are exposed to and raises the question whether they are able to alert the occupants before failing due to heat exposure. Research by Ashley et al. in 2005 showed that approximately 30 s of sounding time is necessary to reliably awaken a sleeping occupant and initiate egress. As research has primarily focused on the activation of smoke alarms, there is a gap in the industry knowledge of the thermally induced failure in these devices. Experiments using two different smoke alarm designs were performed in a heated tunnel with induced airflow. The alarms were heated until they reached a code-mandated audibility failure criterion of less than 5 dB above ambient levels, as well as complete cessation of the audible alarm sound during experimental testing. For these samples, reduction in sound signal started to occur at a component temperature of 56°C, and all alarms had stopped sounding when heated to 144°C. The results of a plunge heating test were used to compute a generalized two-stage Response Time Index for the thermal response of each type of smoke alarm. The output data from the NIST Home Smoke Alarm Tests performed in 2008 were used to calculate the estimated time when the smoke alarm would have thermally failed during those tests. The calculations showed that in the scenarios analyzed, both smoke alarm designs tested would provide more than the 30 s required, before reduced audibility or failure occurs. The failure of both alarm designs in just over 3 min shows that more research is needed applying this methodology to a wider range of alarm models and fire scenarios to ensure that smoke alarms are able to provide adequate protection in modern fires. [ABSTRACT FROM AUTHOR]

Multiple evacuation models were used to simulate different WTC tower evacuations, subject to a number of assumptions. The goal of the modeling was to frame an understanding of actual evacuation findings on September 11, 2001. Simulations demonstrated that a phased evacuation (occupants of the emergency floor, the occupants on the floor above, and the occupants on the floor below were to evacuate to three floors below the emergency floor) would have taken between 4 min to complete (without delays in evacuation initiation) and 11 min to complete (with evacuation initiation delays between 0 min and 10 min). Total evacuation of a tower assuming a full occupant load would have required from 92 min to 142 min. NIST estimated that approximately 14,000 occupants would have been unable to evacuate from WTC 1 and WTC 2 on September 11, 2001 had the starting building population in each tower been 19,800, i.e., a full occupant load without visitors. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to assess the effectiveness of photoluminescent material (PLM) in support of occupant evacuation in office buildings. The first study completed in 1999 was designed to assess the potential use of PLM as a safety communication system to support office occupant evacuation. The study measured the occupant premovement time, movement time and evacuation speed in four stairways with different lighting and PLM installations. The positive outcome of the first study regarding a comparable speed of movement in the different stairways used and the conclusive feedback from the evacuees regarding the PLM wayguidance system led to a second study. The second study, completed in 2008, compared 3 stairway installations of PLM markings and a stairway with emergency lighting, which acted as a reference stairway. Results show comparable speed of movement under severe crowd conditions for the 4 stairways studied. Overall, two-thirds of the respondents felt comfortable going down the stairways with PLM markings particularly in the 2 stairways where the marking was installed across each step. The stairway, which had only emergency lighting, and the stairway with L-shaped markers at the edge of each step were less appreciated by the occupants. Occupants commented that the landings and mid-landings were difficult to identify in all the stairways, which suggest that additional marking should be provided in these areas. The findings of these two studies led to the development of a best practice Guide for installation of PLM marking in exit stairways. [ABSTRACT FROM AUTHOR]

A delay in the pre-evacuation reaction may be one of the reasons causing occupants to be ‘trapped’ in a dangerous zone. Under fire situations, people are found to behave differently in that some may start evacuation immediately, some may ignore the fire alarms and engage in their activities and some others may participate in fighting the fire. These behavioral reaction patterns are influenced by some factors, such as occupant characteristics, building characteristics and fire characteristics. The purpose of this study is to investigate the pre-evacuation behavior of occupants under fire and explore the associations between these factors and the human behavior. To obtain the human behavioral information in real fire, a post-fire survey for a multi-storey office building fire in a major city in Mainland China was carried out with the assistance of local fire professionals. Some of the possible factors that might influence the occupants’ actions at recognitions and response stage were examined. It was reckoned that the behavioral reaction at recognition and response stage was mainly dependent on the human characteristics and building characteristics except the fire characteristics. The results also implied that pre-evacuation time was typically influenced by the occupant characteristics. [ABSTRACT FROM AUTHOR]

It is felt that given recent events, the performance of a population during an emergency procedure is less predictable than was once thought. This has potentially serious consequences during an evacuation, especially where structures have been designed on the basis of the successful application of emergency procedures. The reaction of the resident population to these procedures is sensitive to their normal use of the structure and the level to which the population is engaged and familiar with the procedure. A method is presented to develop procedures for non-emergency and emergency situations in partnership with the resident population, to take advantage of their indigenous knowledge, to improve their familiarity and to engage them in the safety process. This method is appropriate for situations where emergency procedures are normally applied and where the population is not transient; e.g., an office environment, where emergency procedures had been developed. It is felt that by adopting this approach, the population will be more receptive to the application of these procedures and that their response may then be more predictable. As an example of this method, a project framework is outlined in order to describe the approach in sufficient detail and to encourage future application and testing. [ABSTRACT FROM AUTHOR]

In light of the events of September 11, 2001, a concern in the fire safety community is that the public attitudes toward emergency evacuation procedures and preparedness may have changed and that current assumptions about occupant behavior may no longer be valid. In 2006, a survey of high-rise building occupants was conducted to explore their knowledge of high-rise building safety and emergency evacuation procedures and their attitudes and perceptions about high-rise safety and emergency evacuation procedures. Some 244 residential building occupants in Chicago, New York City and San Francisco and 228 commercial building occupants in Boston, Chicago, Detroit, Houston, Los Angeles, Miami, and Philadelphia were surveyed. The study revealed that the events of September 11, 2001 have heightened occupants concerns about safety in high-rise buildings. Eight in ten commercial building respondents participated in a fire drill in the last year, compared to 18% of residential building respondents. Among both survey respondents, the most frequent top-of-mind suggestion to building management to improve safety was “more fire drills.” Almost all occupants know where the fire exits are. And, keeping with conventional wisdom, most occupants believe using elevators is unsafe during a fire, however, 28% also believe that going to the roof is a possible alternative to using the stairs. These findings support the need for continued public education about emergency evacuations procedures in high-rise buildings. [ABSTRACT FROM AUTHOR]