The modeling was completed using PathFinderTM 2020 version 2020.4.0902. Pathfinder 2020™ is a dynamic egress model developed by Thunderhead Engineering.

The model simulates occupant movement toward exits similar to fluid flow, based on occupant movement speeds and flow rates over and through doors, stairs, and corridor spaces.

PathFinderTM 2020supports two movement simulation modes. The SFPE mode is a flow-based egress model where walking speeds and flow rates through doors and corridors are defined. This mode implements the flow-based egress modelling techniques presented in the SFPE Handbook of Fire Protection Engineering [Nelson and Mowrer, 2002] and the SFPE Engineering Guide: Human Behavior in Fire [SFPE, 2003]. The steering mode is an occupant behavior model that uses a combination of path planning, steering mechanisms and collision handling to control occupant motion. This mode offers the most realistic occupant movement and thus, will be utilized in this analysis.

During the simulation, occupants within the different zones move toward exits using exit elements with flows and movement speeds as stipulated in the above referenced SFPE Handbook chapter. The primary constraint is that the occupant movement through open paths, doors, or on stairs, will vary according to the occupant density using these exit elements. The model determines the egress movement time based on the speed/density relationship described in the above referenced SPFE Handbook chapter.