Vertical transport evacuation modelling

Within any high-rise structure or underground/subway station, occupants often heavily rely on vertical transport devices (e.g. escalators, lifts, etc) to travel vertically between levels. Typically such devices provide a faster and more comfortable means to travel than the equivalent stairs. Such devices also provide an additional means for occupant egress. However, the provision for utilising such devices in actual buildings for evacuations is rare. Despite a select number of structures throughout the world allowing the use of vertical transport devices within evacuation scenarios, little is understood with regards to evacuation vertical transport strategies and to what extent such strategies may be influenced by associated human factors. This thesis is intended to address this lack of understanding. The thesis provides an in depth review of evacuation usage of vertical transport devices in actual evacuations, their provision in building codes, empirical studies analysing human factors, representation within simulated environments, and analysis of previously explored operational strategies. The review provides a broad set of research questions that the thesis is intended to address. Human factors data associated with vertical transport device usage have been collected via an online survey and video analysis. The data analysis has instructed the development of the vertical transport device models and associated agent models within the buildingEXODUS evacuation software. The models include the representation of device selection, the influence of local conditions in close proximity to a device, and the influence of wait time upon device selection. The developed models have been used to demonstrate the influence of different vertical transport strategies and to what extent such strategies are influenced by human factors. Finally, the thesis concludes by summarising the increased understanding achieved through the work presented

Congestion in Computational Evacuation Modelling

The time-based analysis of egress scenarios is a long-standing and well-established method to evaluate occupant safety. It is based on the necessary condition that the required egress time is smaller than the available egress time. The former is derived by the application of evacuation models, the latter by calculation of smoke and heat spread in the case of a fire incident. In the calculation of required egress time the time-dependent development of occupant density and consequently the emergence of congestion often play a crucial role. There is a demand to evaluate the development of local occupant density and jam situations independent of the above time-based criterion. This is for example reflected in national guidelines and standards. It is however difficult to obtain general valid evaluation criteria for congestion due to the multitude of influencing parameter and the highly situation-dependent nature of the accompanying boundary conditions. In addition, prediction of localization and duration of congestion may differ from model to model if applied to equal scenarios. Furthermore, close inspection reveals the difficulty to define proper terms for a quantitative definition of congestion. This issue is further analysed in this paper based on three case studies

The development and use of aircraft evacuation modelling as a viable tool for the certification and safety analysis of passenger aircraft

Evacuation modelling technology offers designers and regulators of aircraft new opportunities to rigorously test designs and theories. However, before evacuation models can be used effectively they need to be understood by the regulatory and aviation industry, validated and developed further. This thesis tackles each of these aspects. This thesis provides a detailed review of evacuation modelling with special emphasis on aviation evacuation models and the available data upon which models and understanding can be based. Of these the airEXODUS model is selected for this thesis and it is described in detail and critically evaluated. The evaluation revealed three main issues that needed to be addressed in order for aircraft evacuation modelling to advance. These issues relate to, (1) the limited quantity of model verification, (2) the inability of models to represent crew procedures, and (3) the limited behavioural capabilities of these models with regard to simulating real accidents as opposed to certification scenarios. The fundamental accuracy and predictive capability of airEXODUS is evaluated. This is followed by a comprehensive investigation of cabin crew and passenger behaviour in 90-second certification trials and real emergency evacuations. The conclusions from this investigation serve as the basis for the development of new algorithms to addresses issues (2) and (3). Behavioural algorithms are developed to simulate cabin crew bypass in conjunction with algorithms for passengers exit choice and methods for simulated passengers to optimise their chosen route to an exit. Finally, this thesis concludes by demonstrating the value of evacuation modelling in the design of future aircraft, the regulation of current aircraft and in understanding some of the contributing factors involved in past evacuation related disasters

Vulnerable People in Microscopic Evacuation Modelling

Computational evacuation modelling as a part of approval procedures or design processes is sometimes concerned with vulnerable people requiring special attention. This vulnerability can be based on external circumstances or on individual characteristics. Microscopic methods are well suited to deal with such specific determinants by their ability to model individual movement and certain behavioural aspects. By reference to case studies the possibilities of up-to-date individual evacuation models to cover egress scenarios including vulnerable people are discussed. The selected examples demonstrate that the evacuation of vulnerable people often depends more on the modelling of individual behaviour rather than on a very detailed description of individual characteristics. Group formation and the guidance or assistance of other people will have a strong impact on the evacuation process and thus require special modelling techniques and respective calibration and validation efforts guided by empirical studies

Pedestrian Evacuation Modelling with Dynamics Congestion Avoidance

With the development of computer technology, pedestrian simulation becomes an efficient method to analyse evacuation efficiency under various scenarios. Some important and common behaviour of pedestrians, congestion detection and avoidance, which is seldom considered in pedestrian simulation complicatedly, are discussed in this paper. A modified cellular automata model considering dynamic congestion detection and avoidance is proposed and applied to simulate two different scenarios to demonstrate the effect of congestion avoidance behaviour, which have a significant improvement on evacuation efficiency. The accuracy and efficacy of this model is verified through the comparison result which is conducted through commercial software, Pathfinder. The modified model shows that with the consideration of congestion avoidance behaviour properly, the evacuation efficiency is improved approximately 40% than the model proposed by this paper, without the consideration of congestion avoidance behaviour

Application of shape grammar theory to underground rail station design and passenger evacuation

This paper outlines the development of a computer design environment that generates station ‘reference’ plans for analysis by designers at the project feasibility stage. The developed program uses the theoretical concept of shape grammar, based upon principles of recognition and replacement of a particular shape to enable the generation of station layouts. The developed novel shape grammar rules produce multiple plans of accurately sized infrastructure faster than by traditional means. A finite set of station infrastructure elements and a finite set of connection possibilities for them, directed by regulations and the logical processes of station usage, allows for increasingly complex composite shapes to be automatically produced, some of which are credible station layouts at ‘reference’ block plan level. The proposed method of generating shape grammar plans is aligned to London Underground standards, in particular to the Station Planning Standards and Guidelines 5th edition (SPSG5 2007) and the BS-7974 fire safety engineering process. Quantitative testing is via existing evacuation modelling software. The prototype system, named SGEvac, has both the scope and potential for redevelopment to any other country’s design legislation

Verification and Validation of Viswalk for Building Evacuation Modelling

This thesis is evaluating the pedestrian modelling software Viswalk for the use as a building evacuation model, by verifying and validating the model. In the verification, a procedure from the National Institute of Standards and Technology (NIST) is used as a basis to assess Viswalk’s ability to represent pre-evacuation time, movement and navigation, exit usage, route availability and flow constraints. Seven tests are excluded due to delimitations of the thesis or limitations of the current version of the model. The verification tests show that Viswalk is able to represent the main core components of evacuation models that are under consideration. The model yields results that correspond with the expected results for all 10 verification tests that are performed. However, non-conservative flow rates can be obtained if the default input settings are used. In the validation, results from Viswalk are compared to four real life experiments including a corridor, a classroom, a theatre lobby and a stair, followed by an uncertainty analysis. With adjusted input settings the movement times deviate with 2-16 % from the experiments and with default input settings the movement times deviate with 12-95 %. The walking speed is an important parameter in the validation tests, even with substantial congestion, with up to 46 % increased movement times when the walking speeds are decreased with 25 %. In the validation it is also noted that the occupant densities in front of openings can differ with up to 45 % between the simulations and the experiments. Despite the aspects described above, results that are close to experimental results can be obtained if the user has a good estimation of the occupant demographics and is aware of the limitations of the model.The computer program Viswalk is a known simulation tool in traffic planning, but is a rather new addition when it comes to building evacuation modelling. The program is therefore evaluated by basic tests and compared to previous evacuation experiments to see how well it predicts pedestrian movement. As our cities increase in population density, more and more high and complex buildings get built, which places high demands on fire safety. In 2013, 104 people died in Sweden due to fires and to prevent these deaths, the fire protection designs of buildings have to keep up with the development of complex buildings. There are currently computer programs and hand calculations that can be used to estimate how long it will take for people in a particular building or area to walk from point A to point B. A computer program that can be used for this purpose is Viswalk. Viswalk is mainly used in traffic planning when deciding how buildings, arenas, train stations, intersections and so on should be designed. Since the program can be used in several different areas, it can be a good tool when assessing the fire safety in large and complex scenarios. Few studies have however been performed that focus on Viswalk’s use for building evacuation modelling. The thesis focused on evaluating Viswalk as a building evacuation model, and the program has been assessed both according to guidelines from the National Institution of Standards and Technology (NIST) and by comparisons to previously performed real life evacuation experiments. This is very important from a fire safety perspective since it is essential when using these types of programs that the results correspond with reality. The program was verified, which means that the fundamental assumptions used by the program were tested and evaluated with simple tests. This included for example to test if the walking speeds that were specified by the program user matched the walking speeds that were obtained when running the program. The real life experiments that were used included a corridor, a classroom, a theatre lobby and a stair to evaluate the program for realistic everyday situations. In the evaluation, the pedestrians’ movement times from the experiment were compared to those from the program to see if they matched. The results from the evaluation showed that results that are close to experimental results can be obtained if the input parameters are adjusted to correspond with the populations from the experiments. The program yielded movement times that deviated with 2-16 % from the four experiments and the results from the verification tests corresponded with the expected results. However, non-conservative flow rates can be obtained if the default input settings are used. It was also noted that the walking speed was an important parameter, even with substantial congestion, with up to 46 % increased movement times when the walking speeds were decreased with 25 %. Another finding was that occupant densities in front of openings can differ with up to 45 % between the simulations and the experiments

Balancing operating revenues and occupied refurbishment costs 1: problems of defining project success factors and selecting site planning methods

In planning the refurbishment of railway stations the spatial needs of the contractor and of the ongoing business stakeholders have to be balanced. A particular concern is the disruptive effect of construction works upon pedestrian movement. RaCMIT (Refurbishment and Customer Movement Integration Tool) was a research project aimed at addressing this problem. The objective of the research was to develop a decision protocol facilitating optimisation of overall project value to the client's business. This paper (the first of two) presents a framework for considering public disruption in occupied refurbishment using two case studies in large railway stations as examples. It briefly describes new tools which (combined with existing techniques) assist decision making in the management of disruption. It links strategic with sitebased decision making and suggests how public disruption may be treated as a variable to be jointly optimised along with traditional criteria such as time, cost and quality. Research observations as well as current literature suggest that for overall decision-making, opportunities may be lost (under current practice) for minimising joint project cost/revenue disruption, and, for spatio-temporal site decision-making, effective and efficient tools now exist to model both sides of the construction site boundary