Formation of Flow Units During High-rise Building Evacuations

A new concept of a flow unit (people travelling concurrently at the same speed) is introduced to explain the variance in predicted evacuation times that exists when using density correlations. Within the flow units, the first person is found to be setting the pace for the other members of the flow unit. Five different types of flow units are identified based on the behavior of the first person in the flow unit. By properly identifying flow units, the predicted movement speeds of the building occupants are significantly more accurate.