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Emergency Evacuation and Safety in Complex Environments
Full text linkEffective egress system design and management are both fundamental in order to guarantee people's safety in case of compartment fires. In this thesis PASS (Preliminary Assessment of the egress System Safety), a method that allows a rapid screening of the egress system vulnerability, is proposed as a complementary tool to traditional safety assessment methods.
PASS is a set of simple equations that allows assessing at different levels of analysis the egress system performance without simulating the evacuation process. Its equations incorporate factors for including in the analysis the main interrelationships between people-egress system-environment, and for linking the two main concepts of fire sciences: ASET and RSET. In PASS, ASET is estimated through the use of standard times, and simple tools were developed in order to allow their rapid calculation. The results obtained with these tools were compared with results from the computational fluid dynamics model FDS, and a good agreement was found for a set of reference scenarios.
Some factors adopted in PASS to consider people-egress system interrelationships were quantified through experiments carried out in the novel laboratory LabCUBEegress. LabCUBEegress is a movable laboratory with a flexible configuration which can be customised to create several layouts and to reproduce different parts of an egress system. It was conceived and designed in order to quantify human behavioural factors. A set of experiments involving a wide cross-section of population were performed and the effects of exit signs on people's choice at a T-intersection were investigated. The results revealed that with a left exit sign only 70% of individuals choose the shown direction and this value drops to 60% for groups. These results were used to calibrate a PASS factor and were eventually integrated into the method.
Finally, PASS was applied to a case study. Its results were compared with two evacuation models (STEPS and FDS+Evac) and data collected from an announced evacuation drill. A good agreement between PASS analysis, experimental and numerical data was obtained for the scenario studied (a secondary school).
Thanks to the results achieved, PASS can be proposed as a simple and rapid stand-alone tool for the pre-design and management of the egress system safety. For extending the range of validity of PASS, in future works the method may be tested in different scenarios
Application of rapid method for checking egress system vulnerability.
No full textTo ensure people's safety in case of fire in buildings it is fundamental to design and manage an effective egress system. Generally, the design and management of the egress system safety is achieved using either the prescriptive codes or performance based tools (mainly evacuation models). In this paper PASS (Preliminary Assessment of the egress System Safety), a method developed to allow a rapid screening of egress system vulnerability, is presented and applied to a case study. PASS is a set of simple analytical equations that allow assessing at different levels of analysis the egress system performance without simulating the evacuation process. It incorporates factors used to include in the assessment the main interrelationships between people-building-environment and to adapt PASS to different scenarios. The method was preliminary applied to a case study (high school). PASS results were compared with two evacuation models (STEPS and FDS+Evac) and data collected from an announced evacuation drill. A good agreement between PASS analysis, the data collected during the evacuation drill and the evacuation models was obtained. © 2013 Elsevier Ltd
PASS: a test-based Method for a Preliminary Assessment of the Egress System Safety
No full textThe design and adoption of an effective egress system is a necessary measure to accomplish the objectives required for people's safety in case of fire. Once the designed egress system has been realized, people safety issue moves from a design perspective to a management problem, as stated by Fire Safety Engineering standards. To manage effectively the egress system safety, it is advisable that the stakeholders (designer, safety manager, etc.) have simple, quick and effective tools to use both for understanding how the egress system works, and to check its strengths and weaknesses, considering different scenarios.
In this work the authors present and discuss PASS (Prelirninary Assessment of the egress System Safety), a test-based method developed adopting a vulnerability approach. PASS may be used for a quick assessment of the egress system safety, in order to identify its weaknesses without resorting to a simulation of the evacuation process. As a part of a validation study, PASS has been applied to analyse an existing egress system: in comparing the outcomes of PASS, STEPS, Evac, along with the data obtained from an evacuation drill, PASS has demonstrated itself as a quick method for a preliminary assessment of egress system performance
LabCUBEegress: a laboratory for a selective study of people’s movement and human behaviour during egress situations
No full textQualitative and quantitative studies of people's movement and behaviour during egress situations are fundamental in order to characterize the interrelationships between people and the environment and, eventually, to i m prove the effectiveness of the design and management of an egress system. The complexity of the evacuation process is generally studied by performing evacuation drills and controlled experiments. Evacuation drills permit to analyse the whole evacuation process but they are not usually replicated in the same building. Hence, the data collection is possible for a single scenario. On the other hand, controlled experiments allow to focus the study on one or few types of interactions and to repeat the analyses several times for the same scenario in order to collect representative data on movement or behavioural patterns. In order to perform experiments aimed at studying people-people and people-environment interrelationships a portable laboratory, LabCUBEegress, has been conceived and realized. LabCUBEegress is a structure with a flexible configuration which can be customised to create different layouts and to reproduce different parts of an egress system. LabCUBEegress has been used in different set of experiments aimed at studying the effects of exit signs on people's path choice, the movement of people in paths with different widths, and the effects of flows from opposite directions at a gap. In this paper LabCUBEegress is presented along with the results obtained from the study of the effects of exit signs on people's path choice at a T-intersection. The results show that the presence of a left exit sign at a T-intersection influenced people's path choice in both individuai and group experiments, with a stronger intluence in individuai experiments. The proportion of people that selected the left path increased significantly if compared with the scenarios without exit signs
People's Movement in Narrow Paths with Different Width
No full textOne of the most critical issues to manage in case of accidents in
industrial facilities is people evacuation. The outcome of the
evacuation process depends on many factors, including the adversity of
the accidental event, the behavioural features of people involved, the
functional vulnerability of the system, such as the geometrical layout
of the egress system.
In order to reach a safety place in industrial facilities, people can be
driven to go through narrow corridors or passages due to the peculiarity
of the work place. Such passages force people to move in a single line
and can reduce the movement speed, thus increasing the time required to
evacuate.
In this work we analyse people's movement in paths with two different
widths (0.8 and 0.9 m) and with the presence of different types of
curves (90 degrees and 18 degrees). The data were collected in the
LabCUBE(egress) experimental laboratory, a portable structure with a
flexible layout designed by researchers of University of Udine. In this
paper we present the results obtained from the experiments and simple
relationships between people's speed and the path width. These equations
can be a useful tool to help in designing the egress paths as well as in
assessing the vulnerability of existing egress systems where narrow
paths are present
A sensitivity analysis of available safe egress time correlation
No full textThe people fire risk assessment in industrial premises, buildings or confined spaces can be accomplished by comparing the time for the onset of life threatening conditions (Available Safe Egress Time, ASET) with the time that people take to move away from the threatening zone and to reach a safe zone (Required Safe Egress Time, RSET). For a given scenario, people are considered safe if ASET is greater than RSET. The ASET is usually assessed by using either analytical equations or fire simulation models. Due to their simplicity and quick use, analytical equations could be suitable for preliminary and routine assessment of people fire risk. On the other hand, fire simulation models are time-requiring tools (both for the modelling and simulation phases) but can be used for deterministic and design analyses, where much details are often required. This study aims at comparing the results obtained by using the analytical equation proposed by Karlsson and Quintiere with the data obtained by using CFD simulations of the same scenarios. Furthermore, a sensitivity analysis on the main input data of the analytical equation has been performed. A non-adiabatic compartment has been modelled with floor, ceiling and walls at constant temperature (T = 293 K)
Analisi di sensitività del tempo disponibile per l'esodo (ASET) in caso di incendio in spazi confinati.
No full textL’evacuazione sicura delle persone in caso di incendio può essere progettata e gestita attraverso la stima del tempo massimo a disposizione per allontanarsi dalla zona coinvolta dall’evento (Available Safe Egress Time, ASET). L’ASET è generalmente valutato ricorrendo a diversi parametri prestazionali e calcolando il tempo di raggiungimento di una fissata soglia per ciascun parametro adottato. In questo lavoro è presentata l’analisi di sensitività del tempo di raggiungimento dell’altezza minima dello strato libero da fumi in spazi confinati al variare della velocità del rilascio di energia durante l’incendio (Heat Release Rate, HRR), dell’area della stanza (Af) e dell’altezza della stanza (H). L’analisi è stata inizialmente effettuata utilizzando un metodo analitico di tipo integrale. I risultati sono stati poi confrontati con i dati ottenuti dall’utilizzo del modello fluido-dinamico computazionale FDS (Fire Dynamics Simulator). Nonostante alcune differenze tra la metodologia analitica e il modello FDS rispetto all’andamento dell’ASET al variare dei parametri considerati, la metodologia analitica si è dimostrata robusta rispetto alle variazioni di Af e di H. Inoltre, nell’intervallo 0.06 < H/Af < 0.48 m-1 e per volumi inferiori a 4800 m3, i dati di ASET ottenuti sono del tutto confrontabili con quanto ottenuto mediante il modello fluido-dinamico
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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