An experimental data-set on merging flows in rail tunnel evacuation

The main purpose of this study was to investigate the impact of merging conditions during evacuation process in rail tunnels. The experiment was carried out in a mock-up of a rail car with a single exit towards a lateral corridor. Eight exit configurations were tested involving 77 participants with a reasonable proportion of ageing subjects (age mean 48; standard deviation 15; range 18-74). New measurements and data processing methods were proposed and used. The novel contribution of this study was the use of flow distributions rather than flow rates. The proposed new random variable (the instantaneous specific flow) is derived from a straightforward way of measuring the flows (i.e. the time intervals between participants passing a reference line). The collected flows were classified and combined to produce a set of 10 flow samples for the statistical analysis. Observations from video recordings complemented the quantitative analysis revealing behavioural patterns of participants. The results confirmed that the occurrence of merging had a negative effect during evacuation. The rail car exit flow and the walkway flow decreased when merging occurs. The relationship between both flows varied considerably during the merging period. However, the higher the height differential of the rail car exit the more dominance of the walkway flow. It is also found no gender playing a role in deference behaviour (male helping female).This research was supported by the Spanish Ministry of Economy and Competitiveness for the EVACTRAIN Project grant, Ref.: BIA2011-26738, co-financed by ERD funds. The authors would like to acknowledge the participants for their involvement and patience. Without their cooperation, this research would not have been possible

Scientific knowledge and scientific uncertainty in bushfire and flood risk mitigation: literature review

EXECUTIVE SUMMARY The Scientific Diversity, Scientific Uncertainty and Risk Mitigation Policy and Planning (RMPP) project aims to investigate the diversity and uncertainty of bushfire and flood science, and its contribution to risk mitigation policy and planning. The project investigates how policy makers, practitioners, courts, inquiries and the community differentiate, understand and use scientific knowledge in relation to bushfire and flood risk. It uses qualitative social science methods and case studies to analyse how diverse types of knowledge are ordered and judged as salient, credible and authoritative, and the pragmatic meaning this holds for emergency management across the PPRR spectrum. This research report is the second literature review of the RMPP project and was written before any of the case studies had been completed. It synthesises approximately 250 academic sources on bushfire and flood risk science, including research on hazard modelling, prescribed burning, hydrological engineering, development planning, meteorology, climatology and evacuation planning. The report also incorporates theoretical insights from the fields of risk studies and science and technology studies (STS), as well as indicative research regarding the public understandings of science, risk communication and deliberative planning. This report outlines the key scientific practices (methods and knowledge) and scientific uncertainties in bushfire and flood risk mitigation in Australia. Scientific uncertainties are those ‘known unknowns’ and ‘unknown unknowns’ that emerge from the development and utilisation of scientific knowledge. Risk mitigation involves those processes through which agencies attempt to limit the vulnerability of assets and values to a given hazard. The focus of this report is the uncertainties encountered and managed by risk mitigation professionals in regards to these two hazards, though literature regarding natural sciences and the scientific method more generally are also included where appropriate. It is important to note that while this report excludes professional experience and local knowledge from its consideration of uncertainties and knowledge, these are also very important aspects of risk mitigation which will be addressed in the RMPP project’s case studies. Key findings of this report include: Risk and scientific knowledge are both constructed categories, indicating that attempts to understand any individual instance of risk or scientific knowledge should be understood in light of the social, political, economic, and ecological context in which they emerge. Uncertainty is a necessary element of scientific methods, and as such risk mitigation practitioners and researchers alike should seek to ‘embrace uncertainty’ (Moore et al., 2005) as part of navigating bushfire and flood risk mitigation

Perceived Severity of Visually Accessible Fires

Investigations of past fires suggest that building occupants faced with a fire have problems defining the severity of it, especially in the early stages of the fire. An experiment was therefore carried out to study people’s ability to estimate fire growth, and their perceived ability to extinguish a fire using a portable fire extinguisher. A total of 535 persons, namely 304 men and 231 women, were asked to fill out a questionnaire that was divided into three parts. In the first part the test participants were asked to estimate the time between different stages of a fire. The second part involved estimations of the own ability to extinguish a fire with a portable fire extinguisher. The third part involved general questions about age, gender and academic background. The results suggest that people in general are not very good at defining the severity of a fire when it is visually accessible. Estimations of the fire growth did not correspond very well to the actual fire growth, and a great proportion of the test participants believed that they had not been able to extinguish an extinguishable fire using a portable fire extinguisher. It is therefore argued that the perceived risk not always conforms to the real risk in a fire situation where the fire is visually accessible. The results can be used to explain why building occupants not immediately initiate evacuation in a fire situation, even when the fire is visually accessible