The Deadly Challenge of High-Rise Evacuations: Lessons from Hong Kong's Tragic Fire

Stairwells are the only reliable escape route in most buildings.

Melbourne:

The devastating Hong Kong high-rise fire that engulfed multiple buildings in a large residential complex has resulted in 44 confirmed deaths, with approximately 300 individuals still missing.

Dozens of people are hospitalized with serious injuries, making this one of Hong Kong's deadliest building fires in recent history and the most severe since the 1996 Garley Building disaster.

While reports indicate over 900 people have been evacuated from Wang Fuk Court, uncertainty remains about how many residents might still be trapped inside.

The catastrophic fire—believed to have spread between buildings via burning bamboo scaffolding and accelerated by strong winds—underscores the significant challenges of evacuating high-rise structures during emergencies.

High-rise evacuations don't occur daily but happen frequently enough to be concerning. When they do, consequences are nearly always severe. The risk is particularly high in buildings that are predictably occupied: residential towers at night and office buildings during daytime hours.

This pattern has been evident in major incidents from the World Trade Center in the US to Grenfell Tower in the UK. Once fires take hold, evacuating thousands of people down numerous floors becomes a race against time.

The challenges of evacuating tall buildings go beyond simply getting people out—they involve a complex interaction between the building's physical limitations and human behavior under extreme stress.

The most fundamental barrier is vertical distance. In most buildings, stairwells represent the only dependable escape route.

Actual stair descent during evacuations proceeds much slower than generally anticipated. Under controlled conditions, individuals move downward at approximately 0.4-0.7 meters per second. However, during genuine emergencies, particularly in high-rise fires, this speed can decrease significantly.

During 9/11, documented descent speeds among survivors often fell below 0.3 meters per second. These slowdowns accumulate dramatically over extended vertical distances.

Fatigue plays a critical role. Extended walking substantially reduces descent speed. Post-incident surveys confirm that a substantial majority of high-rise evacuees pause at least once. Following a 2010 high-rise fire in Shanghai, nearly half of elderly survivors reported significant deceleration.

Lengthy stairwells, landings, and high-rise stair configurations all contribute to congestion, particularly when evacuees from multiple floors converge into a single shaft.

Slower-moving individuals include elderly people, those with physical or mobility challenges, and groups evacuating together. These factors reduce the overall evacuation pace compared to speeds typically assumed for able-bodied individuals, creating bottlenecks. This variation is especially relevant in residential buildings with diverse occupant populations.

Visibility is another crucial factor. Experimental studies demonstrate that reduced lighting significantly slows stair descent. This suggests that when smoke diminishes visibility during actual events, movement may slow further as people hesitate, misjudge steps, or adjust their pace.

Human behavior represents one of the most significant sources of delay in high-rise evacuations. People rarely respond immediately to alarms. Instead, they pause, seek confirmation, assess conditions, gather belongings, or coordinate with family members.

These initial minutes consistently prove to be some of the most costly when evacuating tall buildings.

Studies of World Trade Center evacuations reveal that the more cues people observed—smoke, shaking, noise—the more they sought additional information before moving. This search for meaning creates delays as people consult colleagues, look outside, contact family, or await announcements. Ambiguous signals further extend these delays.

In residential towers, families, neighbors, and friend groups naturally attempt to evacuate together. Groups tend to form wider configurations that reduce overall flow. However, research indicates that when groups move in "snake" formations—single file—they travel faster, occupy less space, and allow others to pass more easily.

These patterns are significant in high-rise housing, where diverse household types and mixed abilities make group movement common.

As high-rises grow taller and populations age, the assumption that "everyone can take the stairs" is no longer valid. Complete building evacuation can take too long, and extended stair descents may be impossible for many residents, including older adults, people with mobility limitations, and families evacuating together.

This is why numerous countries have implemented refuge floors: levels within towers protected from fire and smoke that serve as safe staging areas. These reduce bottlenecks and prevent lengthy queues, providing safe places to rest, transfer to clearer stairs, or await firefighter assistance. Essentially, they make vertical movement more manageable in buildings where continuous descent isn't realistic.

Evacuation elevators represent another solution—lifts engineered to operate during fires with pressurized shafts, protected lobbies, and backup power systems. The most efficient evacuations utilize a combination of stairs and elevators, with ratios tailored to building height, density, and demographics.

The conclusion is evident: high-rise evacuation cannot depend on a single approach. Stairs, refuge floors, and protected elevators should all be incorporated to enhance the safety of vertical living.

Milad Haghani, Associate Professor and Principal Fellow in Urban Risk and Resilience, The University of Melbourne; Erica Kuligowski, Principal Research Fellow, School of Engineering, RMIT University, and Ruggiero Lovreglio, Professor in Digital Construction and Fire Engineering, Te Kunenga ki Pūrehuroa - Massey University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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