Fire Safety Science Digital Archive

We conducted travel speed measurements to clarify the effect of visibility on evacuee’s performance. As visual ability is dependent on the individual, members of the two age groups (30 youths and 30 seniors) were subjected to a visual acuity test prior to the travel experiment. In our research, we define subject’s visual acuity as recognizable threshold of form perception using Landolt Ring. Visual acuity is a person’s ability to see distinctly the details of an object. We set eight levels of floor illuminance, complete or incomplete adaptation conditions and luminous conditions with or without smoke. Since the travel speed of the younger group was faster than that of the older group, regardless of illuminance level or smoke density, the difference in travel speed can be predicted by visual acuity. In this report, we constructed a calculation model to predict travel speed as functions of the luminous environment (incorporating illuminance level, adaptation condition, and smoke density) and evacuee’s visual acuity. This model helps us predict performance of evacuees under fire, smoke or blackout conditions.