A Method for the Analysis of Behavioural Uncertainty in Evacuation Modelling

Evacuation models generally include the use of distributions or probabilistic variables to simulate the variability of possible human behaviours. A single model setup of the same evacuation scenario may therefore produce a distribution of different occupant-evacuation time curves in the case of the use of a random sampling method. This creates an additional component of uncertainty caused by the impact of the number of simulated runs of the same scenario on evacuation model predictions, here named behavioural uncertainty. To date there is no universally accepted quantitative method to evaluate behavioural uncertainty and the selection of the number of runs is left to a qualitative judgement of the model user. A simple quantitative method using convergence criteria based on functional analysis is presented to address this issue. The method permits (1) the analysis of the variability of model predictions in relation to the number of runs of the same evacuation scenario, i.e. the study of behavioural uncertainty and (2) the identification of the optimal number of runs of the same scenario in relation to pre-defined acceptance criteria

An analysis of evacuation travel paths on stair landings by means of conditional probabilities

This paper analyses data on occupants׳ movement on stair landings collected during an evacuation drill performed in a six-storey office building in the United States. A total of 215 occupant travel path trajectories were filmed and time on the stair landings and egress behaviours were analysed. Data were analysed using a probabilistic approach, i.e., the probability of different occupant travel paths were calculated in relation to two different factors: (1) crowding on the landings, and (2) the type of interactions between occupants (e.g., merging flows, deference/overtaking behaviours, etc.). Results showed that a higher number of occupants on stair landings caused an increase in the probability for (1) longer travel paths and (2) usage of the outer boundaries on the stair/landing connections. This paper highlights that data and modelling assumptions should be used after a careful evaluation of their field of applicability. In the case of a low occupant load and non-homogenous merging streams (a higher number of people entering the landing from the stairs than the door), floors tend to be emptied from the top to the bottom

A probabilistic approach for the analysis of evacuation movement data

This paper presents a probabilistic approach to analyse evacuation movement data. The approach relies on a detailed video analysis of people movement and pattern reconstruction. Conditional probabilities for travel path trajectories, walking speeds, and physical area occupied on stair landings are calculated for the evacuee population. The approach has been applied as a case study using data from an evacuation drill performed in a six-storey office building in the United States. The evacuation drill was filmed and occupant's behaviours on stairs were analysed using the new method. A comparison with the deterministic methods currently employed in engineering practice has been performed. The benefits of the probabilistic approach are discussed, including (1) a more accurate representation of people movement and (2) the use of probabilistic data for modelling purposes, i.e., model validation and model development

The Process of Verification and Validation of Building Fire Evacuation Models

To date, there is no International standard on procedures and tests to assess the verification and validation (V&V) of building fire evacuation models. Often it is the case that model testers adopt inconsistent procedures, or tests designed for other model uses or they do not test them for all features embedded in their model. 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 (e.g. building fires instead of maritime applications). This document 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. A review of the current procedures, tests and methods available in the literature to assess the V&V of building evacuation models is provided. The capabilities of building 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. A set of tests and recommendations about the verification and validation of building evacuation models is proposed. These tests include suggestions on using simple tests of emergent behaviours together with examples of experimental data-sets suitable for the analysis of different core components. The uncertainties associated with evacuation modelling are discussed. In particular, a method for the analysis of behavioural uncertainty (uncertainty due to the use of distributions or stochastic variables to simulate human behaviour in evacuation modelling) is presented. The method consists of a set of convergence criteria based on functional analysis. The last part of this document presents a discussion on the issues associated with the definition of the acceptance criteria of a standard V&V protocol

Assessing the Verification and Validation of Building Fire Evacuation Models

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

Predicting Flashover Occurrence using Surrogate Temperature Data

Fire fighter fatalities and injuries in the U.S. remain too high and fire fighting too hazardous. Until now, fire fighters rely only on their experience to avoid life-threatening fire events, such as flashover. In this paper, we describe the development of a flashover prediction model which can be used to warn fire fighters before flashover occurs. Specifically, we consider the use of a fire simulation program to generate a set of synthetic data and an attention-based bidirectional long short-term memory to learn the complex relationships between temperature signals and flashover conditions. We first validate the fire simulation program with temperature measurements obtained from full-scale fire experiments. Then, we generate a set of synthetic temperature data which account for the realis-tic fire and vent opening conditions in a multi-compartment structure. Results show that our proposed method achieves promising performance for prediction of flashover even when temperature data is completely lost in the room of fire origin. It is believed that the flashover prediction model can facilitate the transformation of fire fighting tactics from traditional experience-based decision marking to data-driven decision marking and reduce fire fighter deaths and injuries