Acquisition of Informal Information can Influence the Decisions of Building Occupants During a Phased Evacuation

Abstract For a phased evacuation strategy, the occupants on floors apart from where a fire has broken out are expected to wait to evacuate, and sometimes security control center staff will instruct them to wait. Meanwhile, occupants may obtain information about a fire in other ways, such as by watching smoke ascending outside the building, or from photos or videos posted on social networking services (SNS) by people outside the building. This study examined the occupants’ thoughts and decisions when they received such informal fire information while waiting for phased evacuation through experiments with participants in a virtual high-rise building. Experiments involved 85 fire safety professionals and 72 laypeople. The entire process of entering the building, ascending to the conference/meeting room on the 40th floor, and waiting there was replicated in first-person or over-the-shoulder perspectives in the 2D movies. Announcements, the appearance of smoke, and SNS posts were also replicated. Approximately 70% of both professionals and laypeople followed the instructions for a phased evacuation when they acquired no informal fire information; however, the percentage dropped to approximately 50% if they acquired informal information. Among professionals, 13–52% of them answered that they would descend the staircases regardless of any staff instructions to wait. The fire safety knowledge that professionals possessed seemingly resulted in them noticing contradictions between cues and more chose an evacuation action that conflicted with the phased evacuation announcement. Fire and smoke control aimed at preventing heightened anxiety among evacuees is also necessary for a phased evacuation strategy. Graphical Abstract