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Visualizing Safer Evacuations

Getting people out of a building quickly and safely in an emergency is a top concern of crisis managers. Two new tools may help them achieve that goal.

One is a computer simulation software program that tries to factor in how people react in evacuation situations. It is intended to help emergency preparedness teams spot critical problems that might not show up in everyday drills.

The software, called the Evacuation Planning Tool (EPT), was developed by Linthicum, Maryland’s Regal Decision Systems for the U.S. Department of Homeland Security (DHS) in collaboration with the Department of Defense’s Combating Terrorism Technical Support Office.

The program is built around a facility schematic provided by the client. The viewer sees a display that represents the facility in three dimensions; the simulation can show whatever a client chooses—a relatively calm, ordered evacuation or a more harried evacuation. As the simulation progresses, tiny icons representing evacuees migrate toward the building’s exits.

Because accurate recreation of evacuation conditions in a drill is impossible, the simulations can help highlight unseen problems. After running simulations, clients might reposition furniture near an exit or divide up emergency supplies to prevent a mob from forming around a single location, says Brian Schaedel, Regal Decision Systems’ assistant business development manager.

The central challenge for the developers trying to make the simulations more realistic is getting data on how people react in real evacuations.

Jeffrey Tubbs, associate principal of design firm Arup Fire and author of Egress Design Solutions: A Guide to Evacuation and Crowd Management Planning, points to news footage of 2003’s deadly fire at The Station nightclub in West Warwick, Rhode Island, as a rare instance in which an evacuation was captured on video.

The “behaviors” programmed into evacuation simulations are based on anecdotal evidence drawn from case-by-case observation. One observation is that when evacuees start to bunch up at a doorway, if one person peels off from the group, others will assume that individual is aware of a faster alternative exit and will follow.

That phenomenon was programmed into EPT and was later observed in evacuations of federal buildings during an accidental violation of restricted airspace over Washington, D.C. last April.

Another variable is evacuees’ reaction when first responders approach or pass them from the opposite direction. Incident managers obviously don’t want evacuees to stop, but they often do so reflexively, just as they would on the road when a police car or fire engine approaches under lights and sirens.

Regal Decision Systems is also working on a second tool, the Regal Evacuation Guidance System (Regal EGS), that may help in evacuations by providing active sensing of threats, coupled with real-time communication that guides evacuees via centrally controlled, color-coded strip lighting on the floors and walls of corridors. The company has worked on one such system intended for the Pentagon.

Incident managers would view a three-dimensional rendering of a structure, upon which threats such as fire or hazmats are mapped, Schaedel says.

Based on those threats, corridor lighting is configured to guide evacuees. Green means that evacuees should head in that direction, while red means an occupant should shelter in place. To address concern about diversion behavior, orange lights indicate that occupants should evacuate in that direction, but expect first responders to enter from that direction as well. Budgetary constraints, however, have stalled full implementation of Regal EGS, Schaedel says.