A look at several creative methods envisioned to assist in emergency evacuation
As buildings get taller, we look for means to navigate them quickly. The lift industry has developed various methods to ensure a quick and efficient distribution of people throughout a building, including transporting people up 80-plus floors in minutes. But, what happens when there is an emergency, and we have to get the people out? In this situation, we cannot use the technology designed to efficiently distribute the flow of people; instead, occupants are expected to descend slowly down thousands of stairs. While these protected stairwells offer a safe egress route away from the threat of fire and smoke, they can become compromised by slower people and take hours to navigate. Elderly, disabled and obese people, as well as people carrying small children, simply cannot get down stairs quickly enough. Often, both firefighters and evacuating residents share a single stairwell, with firefighters climbing the stairs against the evacuating traffic. To enable the firefighters unobstructed access, at least in the U.K., residents in towers whose flats are not affected by fire or smoke are usually advised to stay in place; however, that practice began being criticized following the fire at Grenfell Tower on June 14, 2017. The need for efficient evacuation methods has never been so great.
The challenges faced in protecting the lift car and shaft from heat/fire/smoke and loss of power mean that lifts are generally reserved only for the evacuation of mobility-impaired individuals. This could all change, however, with installations like the one done by thyssenkrupp (14 lifts with Occupant Evacuation Operation functionality) in San Francisco's 181 Fremont.
Other solutions have been suggested and used over the years. Historically, a popular method has been the use of a chute. Resembling the popular child’s playground slide, many early escape tubes were made entirely of metal. Evacuation via these chutes was not perfect. Descent was uncontrolled and could result in injury, as users piled up at the bottom. Also, the fire could heat the metal, causing the people using it to become severely burned while exiting the building. Modern designs are made of strong flame-retardant fabric. Most are collapsible, allowing them to be stored safety until deployment.
A new version of the evacuation slide was invented by Chinese national Zhou Miaorong. According to Mirror, he came up with the idea following a fire at his own block of flats. His slide can accommodate 100 people, evacuating them at a speed of 3 s per floor. The slide folds against the wall when not in use. The inventor spent two years designing the slide and demonstrated it publicly in 2016. While it can be housed within a protected stairwell, this does reduce the stairwell to a single flow of traffic.
There are many fabric chutes available on the market. The Escape Chute from Axel Thoms features a spiral slide that hugs to the side of a descending person, reducing the descent speed to a safe 2 m/s. The manufacturer claims children, disabled persons, pregnant women and even unconscious persons can use an Axel Thoms Escape Chute, as neither user technique nor weight has a significant impact on the speed of descent.
Eric Hooper's escape chute system
British Designer Eric Hooper created an escape chute system that supports a user by the waist. The user then controls their descent by pushing against the sides. Single chutes can be installed with steel frames that can provide a roof-to-ground evacuation point for buildings up to 105 m in height.
One thing these chutes have in common is that they do not appeal to people who suffer from claustrophobia. The diameter of the chute could also be an issue for larger occupants.
Alternative Methods of Escape
Lifts, chutes and drones (as we saw in the February 2020 Web Exclusive) aside, there have been a few more imaginative designs proposed over the years. The Nerigo Emergency Evacuation Lift for High-Rises was designed by Korean company Neri-Go. It carries one or two passengers at a time from floor to floor using the passenger’s body weight to descend. At each floor, the passenger steps off onto the next platform and so on down the building. The platform rises back up automatically when the passenger steps off. It is a simple system that requires no power; however, it does rely on a slow and orderly evacuation, which is not always possible. Interestingly, the Startup Selfie blog claims:
“This sounds like a better evacuation alternative for the elderly resident who cannot easily use the stairs to escape to safety. According to the BuyKorea website [which now seems to be defunct], it can accommodate those carrying children, as well as the disabled."
The Escape Rescue Standard System
The Escape Rescue Standard System was developed by Escape Rescue Systems Ltd. in response to 9/11. This system, previously featured in ELEVATOR WORLD in November 2013, consists of an array of up to five collapsible cabins, permanently stored on the roof in a folded position, back and out of sight. Upon deployment, the cabin array travels out to the façade of the building and is lowered to the ground. It then unfolds, enabling emergency responders to board the cabins.
The extended array travels upward, until it stops outside five floors, enabling up to 30 people to board each cabin through specially configured exit windows simultaneously. The array is then lowered to the ground, and the evacuees on each cabin exit as it refolds. The system repeats this cycle, transporting responders up and into the building and evacuating people as required.
Another product inspired by 9/11 is the SOS parachute, invented by Morris Shahbayi. Intended as a last-resort measure, rather than a planned evacuation tool, this emergency chute can open in 100 ft, far faster than conventional parachutes. It can be used from heights above 50 m (17 floors) and reduces the speed of the fall due to the resistance it generates as it descends. Shahbayi has such faith in his system that he has tested it himself. He hopes it could soon become commonplace in high-rise blocks around the world.
It should be noted, however, that this is not a "one-size-fits-all” solution like a life jacket. The parachute has to be provided in advance so the user can adjust it to fit and familiarize themselves with the instructions. The parachute can then be stored, ready for use. Use of the parachute could also be restricted by the environment surrounding the building.
The age-old problem of how to escape a fire in a tall building has led to many diverse evacuation solutions, and new ones are being conceived all the time (the aforementioned NET GUARD drone concept designed by a group of six students in Guangzhou, China).
However, none of these solutions could be used as a complete evacuation solution for hundreds of people. So, for now, it seems we will have to keep using the stairs.