Investigating evacuation lift dispatch strategies using computer modelling

This paper presents a detailed description of an agent-based lift (elevator) model developed within building EXODUS software intended to represent evacuation scenarios. The main components of the lift model are described including the lift: kinematics, attributes and dispatch control. The agent–lift interaction model is also described, including the lift bank selection, the lift waiting area behaviour (wait location selection and wait duration) and the lift car selection and entry. The lift model is used to investigate a series of full building evacuation scenarios based on a hypothetical 50 floor building with four staircases and a population of 7840 agents. The analysis explores the relative merits of using up to 32 lifts (arranged in four banks) and various egress lift dispatch strategies to evacuate the entire building population. Findings from the investigation suggest that the most efficient evacuation strategy utilizes a combination of lifts and stairs to empty the building and clear the upper half of the building in minimum time. Combined stair lift evacuation times have been shown to be as much as 50% faster than stair only evacuation times. The introduction of the agent milling behaviour resulted in reductions in evacuation times compared with the same scenarios without milling behaviour.