Increasing Risk by Avoiding Communication: Emergency Public Warnings. Jonathan D. Sime, Jonathan Sime Associates (JSA), Research Consultants, 26 Croft Rd., Godalming, Surrey GU7 1BY, UK
This paper considers the way in which poor risk communications have consequences in terms of delayed public response in disasters such as major building fires, crowd crushes and floods. The degree to which people are at risk is defined in terms of a physical threat, where people are and what they know about a risk. As a risk communication defines the degree of risk, it is part of the risk. A perceived risk is real in its consequences, whether it is the risk as quantified, or the risk as conveyed to and viewed by the public who might be at risk, but do not know it. Uncertainties exist in the estimation of a risk, forecasting and monitoring of an evolving hazard. Formal chains of risk communication reflect demarcation lines between custodians of risk information and those potentially at risk. Experts are defined by their knowledge, in contrast to others. Authorities or management may be reluctant to warn the public 'unnecessarily'. Disasters are characterized by delays in warning the public.
A risk increases if a danger evolves, but the knowledge people have of it remains the same up to the point of a dramatic and 'obvious' escalation in the risk (e.g. typical fire disaster, crowd crush scenario). Risk denial, acceptance, or arousal (a risk considered impossible, possible, or an undeniable reality) is a temporal, spatial, psychological and social process. Risk communication is considered broadly in this paper, not only as a message (e.g. conveyed by a pre-emergency instruction video, alarm bell, public address), but in terms of people's location. A building or setting is not only a physical structure, but a communication system.
The paper contrasts two evacuation models, emphasizing movement or communications:
people as information processors: the occupant response time (ORT) model.
Contradictory design, risk decision and communication criteria
predicated on these models are reviewed: e.g. walls = (i) fire
barriers vs (ii) visual barriers to information; (i) centralised,
'autocratic', building intelligence, 'top-down' decision malting
and delayed public warning vs (ii) distributed, 'democratic',
informative, building intelligence and early public warning.
The title of the paper has evolved out of research findings indicating
the need to reconcile the two models. Implications of the ORT
research are considered in relation to pre-emergency and emergency
risk communication technologies and strategies in a variety of
public settings (e.g. underground spaces, complex structures,
sports stadia, airports, ferries, the Channel Tunnel).
References
Sime, J.D. (1996) Assessing the occupant response safety factor in evacuation time calculations. In Interflam '96, Conference proceedings, Seventh International Fire Science and Engineering Conference, 26-28 March, St. John's College, Cambridge. London: Interscience Communications Ltd., (pp 763-775).
Sime, J.D. (1996) Informative flood warnings: occupant response
to risk, threat and loss of place. Current Issues in Total Flood
Warning System Design. International Invitational Workshop, Middlesex
University, 11-15 Sept. 1995, (proceedings forthcoming).