The Effectiveness of Evacuation Alarms in Multi-Hazard Environments

Sammanfattning: The aim of this thesis is to investigate the effectiveness of using specific alarms for each hazard versus the effectiveness of using a single alarm for all hazards in multi-hazard facilities. The research was conducted by disseminating online questionnaires containing audio files of different alarms to occupants of multi-hazards facilities and conducting interviews with safety experts working at multi-hazard facilities. Responses show variability concerning the perceived urgency of an alarm and what respondents associate with that alarm. Each of the alarms were perceived as both ‘not urgent’ and ‘very urgent’ at least once by different respondents, however a trend was observed, suggesting that there might be other factors affecting the perceived urgency than those identified in the literature, for example the pulse pattern. As for the meaning, it could range from a hazard (such as radiation) to a computer error or a reversing truck for the same alarm. The results also indicated that alarms that were perceived as more urgent were also more often associated to a hazard as opposed to alarms that were perceived as less urgent that were more often considered as less hazardous. Responses indicated that people having experienced a real emergency situation preferred the use of multiple alarms more than the people with no experience. Based on the responses, it is recommended that the number of alarms used at a multi-hazard facility should depend on the number of evacuation responses rather than on the number of hazards.