Largely, social science literature reveals that people have multiple concerns about high-rise living including suitability for family living and raising children, neighborly relationships and helpfulness, personal behavior and comfort, perception of safety, tenants’ relation to outdoor spaces and connection to street life [
29,
30,
31,
32,
33,
34,
35,
36,
37,
38]. High-rises’ tenants often feel that they are cooped up in finite spaces of an encapsulated world that fosters loneliness. These environments may make inhabitants also feel claustrophobic, creating a rat-cage mentality. Further, high-rise living could promote poor interpersonal relationships and weak neighborly relationships that may result in a psychological depression. In some cases, the “isolated” nature of high-rise buildings could promote crime. Further, scholars argue that low-rise living is closer to nature and facilitates a stronger community-oriented social life [
30]. As structures grow taller and taller, tenants may perceive that they become increasingly out of touch with the city life.
2.1. Family and Community Living
For children, tall buildings could be “vertical prisons” [
30]. Children may feel in these buildings that they are confined and treated like “a pet on a short leash”. These buildings may offer day care centers and playgrounds “in the sky”; however, children lack spontaneous play and exploration that help them to thrive. Urban psychologists explain that high-rise living can hinder a toddler’s psychological growth. They suggest that one of the best ways for children (ages between 2 and 7) to become independent is by allowing them to gradually go out on their own to experience the real world (e.g., neighborhood, corner store, streetscape, playgrounds, friends and neighbors) and then return home, their haven. Such approach, however, is only attainable in a low-rise environment where parents can see (and may hear) their children from their homes’ windows. This interplay between dependence and autonomy that earns a child a sense of competence is missing in high-rise environments [
37].
The presence or absence of recreational and social outdoor spaces in tall building developments significantly affects the overall residential satisfaction more than that in low-rise environments [
31]. That is, tall buildings’ residents lack front-yards, courtyards, and backyards, and hence public outdoor spaces are critically important for them. When these spaces are absent, residents are “forced” to spend more time indoors, where they may then experience overcrowding or being “imprisoned in the sky” [
31,
32]. Further, when vertical transportation is inadequate or frequently malfunctions, residents will feel discouraged to travel back and forth to amenities provided on the ground floor. Consequently, these amenities will be underused and residents may not reap the full benefits.
High-rises often create disjointed neighborhoods [
29]. They are individualistic, introverted structures that make people feel they are living in “vertical silos”, physically, socially, and psychologically. These buildings appear to be monolithic structures mushrooming in cities without respecting the socio-spatial order of their neighborhoods. When tall buildings are juxtapositioned next to low-rise buildings, residents worry about the loss of privacy since windows and balconies loom over their backyards and shadow their gardens. In his article “The Consequences of Living in High-Rise Buildings”, in the
Architectural Science Review journal (2007), Robert Gifford details six types of fears found in high-rise living as follows [
30]:
Residents fear that a family member or a loved child jumps from a window,
Residents may fear masses of “strangers” that share the same building or floor,
Residents fear a fire that may trap them in the building,
Residents fear a devastating earthquake that will topple the building over them,
Residents may fear becoming ill from communicable diseases generated by the masses who live there, and
Post 9/11, high-rise residents fear that their buildings become terrorist targets
Constantinos Apostolou Doxiadis, a reputable planner and architect, summed up these observations in his writing:
High-rise buildings work against man himself because they isolate him from others, and this isolation is an important factor in the rising crime rate. Children suffer even more because they lose their direct contact with nature and other children. High-rise buildings work against society because they prevent the units of social importance—the family, the neighborhood, etc., from functioning as naturally and as normally as in low-rise environments (p. 82, [
30]).
Skyscrapers substantiate income and racial segregations by creating “vertical gated communities” (VGCs), which limit social interaction and promotion of social capital across socioeconomic groups. As is the case with “horizontal” gated communities, VGCs internalize residents’ social activities that might otherwise invigorate the public realm and enliven street life. Further, high-rises are often the habitats of smaller household size (referring to the number of individuals living in a household) with fewer children. However, research indicates that the presence of a greater number of tenants and particularly children is critical to promote sense of community. Consequently, the chances of having lower sense of community in high-rise developments are greater than that in low-rise developments [
31,
32].
2.2. Disparity in Quality of Life
Tall building may server a wide-range of tenants of various classes and incomes, including upper, middle, and lower classes. However, critiques have focused on tall buildings that cater to either the poor or the rich population. At one end of the spectrum, “vertical slums” have prevailed in poor neighborhoods, for example in the U.S public housing projects. Unfortunately, due to mismanagement, inadequate maintenance, and mediocre architectural design, these buildings suffered from difficult living conditions. They fell into disuse, and eventually, authorities demolished these housing projects. Archetypal projects include the Pruitt–Igoe in Saint Louis, MO, and Cabrini Green in Chicago, IL. Built in the years between 1952 and 1956 and consisted of 33 buildings of 11 story each (totaling about 3000 residential units), the Pruitt–Igoe project suffered immensely from social problems; and consequently, authorities demolished it in the years between 1972 and 1976. Importantly, research indicates that architectural design was not solely responsible for these developments’ failure. Urban policies that “favored” and supported suburban living in the form of offering better educational systems and financial incentives for obtaining mortgages, have exacerbated these problems. Researchers observe these urban policies particularly in the American urban and suburban contexts [
29,
33]. Further, poor design, whether in a low-rise or a high-rise development, often results with lower residents’ satisfaction. However, dissatisfaction in poorly designed high-rise environments could be greater because of their vertical orientation that conveys greater sense of confinement and distancing from the social life on the street [
31,
32].
At the other end of the spectrum, tall buildings have created private, luxury enclaves, or “mansions in the sky” for super wealthy people. These developments offer privacy, top security, restricted access, 24-h closed circuit camera system (CCTV) as well as a wide-range of services—analogous to those provided by luxury hotels. These towers often enjoy the closeness to urban amenities and services such as cinemas, theaters, markets, shopping malls, cafeterias, restaurants, pharmacies, public parks, and mass transit. In short, developers promote luxury high-rise living to enjoy the best of both worlds (urban and suburban) in one place. Nevertheless, these buildings often exclude lower-income communities.
The “mansions in the sky” phenomenon manifests differently in suburbia, where tall buildings are located on spacious land and function as autonomous neighborhoods with their guarded gates, exclusive services, and outdoor amenities, such as golf courses, parks, swimming pools, tennis courts, and marina. For example, Aventura, Florida, contains scattered clusters of “mansions in the sky”, where amenities, services, and facilities are exclusive to tenants and their guests. Unfortunately, in both urban and suburban settings, these communities contribute to social and spatial fragmentations, thereby weakening the bonds of a civic society, and promoting fear and tension among socioeconomic classes [
29,
30].
Recent developments of ultra-luxury residential supertalls in New York City have reinforced the “mansions in the sky” phenomenon. New supertalls (e.g., One57 tower and 432 Park Avenue) are vividly exposing the new “social ladder” of the city by placing the richest people “physically” on the highest altitudes. This new socio-spatial polarization (vertical slums versus mansions in the sky) reinforces social and racial segregations, echoing Pierre Bourdieu’s concept of “symbolic capital” [
29].
Indeed, the “mansions in the sky” phenomenon symbolizes prestige, recognition, wealth, competition, and social class. Steven Holl, a leading U.S. architect [
34], has denounced these developments because they create physical silos and isolate affluent residents from the rest of the city. In this regard, Jenna McKnight cites Aaron Betsky explaining, “Manhattan is being transformed into a Capitalist holy land with no space for the poor” [
35]. He indicated that these tallest luxury residential towers epitomize the skyline’s transformation from a symbol of collective economic prosperity to a symbol of greed, income inequality, and growth of individual wealth.
Indeed, New York City (NYC)’s ultra-luxury towers have drawn extensive criticism from the experts and the public alike. In her article titled “The Logic of Luxury: New York’s New Super-Slender Towers”, Carol Willis [
36] explains that these towers create the following problems:
Skew the housing market by raising price and decreasing affordability to the average residents,
Strain the existing infrastructure,
Cast undesirable shadows on street and public spaces,
Absentee tenants of these buildings fail to support the local economy of businesses and social life of the neighborhood, and
Tax avoidance by non-resident foreigners raises issues of fairness.
Opponents also voiced concerns that numerous purchasers of these residential units have paid from shadowy sources and have taken steps to hide their identities. In particular, overseas investors have been using illicit wealth to purchase properties secretly in luxury residential tall buildings located in “global” cities such as New York, London, and Hong Kong. In their article titled “Stream of Foreign Wealth Flows to Elite New York Real Estate” in
The New York Times, Louis Story and Stephanie Saulfeb [
37] elucidated that hidden ownership of expensive, luxury residences in Manhattan has become a commonplace. In 2008, building owners sold these units for
$5 million or more and shell companies that hid the buyers’ identities bought 39% of those residences. By 2014, the share of hidden buyers for luxury properties rose to 54%. On the Upper East Side, sales to shell companies have reached 42%. In 2014, 54% of sales over
$5 million in Manhattan were to shell companies. In uptown neighborhoods that have new construction, the share exceeds 60%, and in downtown Manhattan, building owners sold 63% of luxury residences to hidden buyers. Story and Saulfeb also bring several alarming stories highlighting these problems by explaining [
37]:
On the 74th floor of the Time Warner Center, Condominium 74B was purchased in 2010 for $15.65 million by a secretive entity called 25CC ST74B L.L.C. It traces to the family of Vitaly Malkin, a former Russian senator, and banker who was barred from entering Canada because of suspected connections to organized crime… Last fall, another shell company bought a condo down the hall for $21.4 million from a Greek businessman named Dimitrios Contominas, who was arrested a year ago as part of a corruption sweep in Greece… A few floors down are three condos owned by another shell company, Columbus Skyline L.L.C., which belongs to the family of a Chinese businessman and contractor named Wang Wenliang. His construction company was found housing workers in New Jersey in hazardous, unsanitary conditions.
Completed in 2004, the Time Warner Center was New York’s trial run of the super luxury, super expensive condominiums. Located in a prestige spot, right at Columbus Circle and privileged with splendid views of the Central park, it is well suited to spark a global phenomenon that spilled over to Hong Kong (e.g., the Cullinan I & II (2008) and the Opus (2012) by Gehry Partners) and London (One Hyde Park (2009) by Rogers Stirk Harbour + Partners). More vividly, towers in the 57th street and its vicinity will likely gain a global status that rivals towers in other cities regarding height and price. For the sake of comparison, the heights of these towers are as follows [
38]:
Cullinan I & II, Hong Kong | 68 stories, 270 m/886 ft |
Opus, Hong Kong | 13 stories, 60 m/197 ft |
One Hyde Park, London | 14 stories, 50 m/162 ft |
432 Park Avenue, NYC | 85 stories, 426 m/1396 ft |
111 West 57th, NYC | 82 stories, 435 m/1428 ft |
Central Park Tower, NYC | 95 stories, 472 m/1550 ft |
Towers in the “Billionaires’ Row” (referring to an area along 57th street and its vicinity) will certainly reinforce the view that New York is a global, cosmopolitan city, where its residents come from all over the world, and its “global” purchasers are not necessarily full-time residents. However, these factors may hurt the social sustainability of the neighborhoods. “Part-time residents” are likely to neither engage in the social life of the neighborhood nor economically benefit its retail, commercial, and grocery stores. In addition, learning that some neighbors purchase their flats using “unlawful” sources is likely to create mistrust and build social barriers among neighbors [
36].
2.3. Human Scale
Humankind is the measure of all things, as Protagoras, the pre-Socratic Greek philosopher, suggested [
39]. Observing human scale in the design of the built environment is essential for providing comfort to users. Because of their great heights, tall buildings, by default, violate human scale. Large cities with a conglomeration of soaring buildings face the challenge of providing a comfortable environment for pedestrians. They are likely to exhibit what Jacobs and Appleyard call “giantism” [
39]. Developments of massive tall buildings cause passersby to feel small, dwarfed, and irrelevant. These negative effects could be of less concern in tall structures such as the Eiffel Tower or Statue of Liberty because their “tallness” is less imposing. That is, these structure are often located in spacious areas (parks, water body, etc.) and hence viewers do not need to bend their heads or “break their necks” to see them. In addition, unlike ordinary tall buildings, these structures are exceptional because they serve symbolic purposes. They are emblematic objects rather than human habitats.
Jan Gehl has written extensively arguing that wonderful places feature three- to six-story buildings. He advocated low- to mid-rise environments as ideal places that can promote walkable and less car-dependent neighborhoods, and asserted that neighborhoods with shorter buildings are more successful urban places than those with taller buildings. He lamented that new skyscrapers, reaching unprecedented heights, are “eyesores” or at least less appealing than the low-slung Parisian urban design model. Overall, Gehl criticized steel-and-glass vertical urbanism for creating unpleasant, soulless, crowded, and inhumanly scaled environments [
18,
19].
Indeed, skyscrapers often shatter the urban scale by dwarfing nearby buildings, people, and public spaces. Pedestrians at the street level are often unable to connect visually with high-rise tenants, architecture, ornamentation, decorative art, and personalized details. For example, pedestrians cannot see the flowerpots in the upper-story windows, which bring a touch of humanity. Pedestrians also cannot completely see the high-rise building; instead, they see “urban canyons” that make them feel visually disoriented. Jane Jacobs argued in her seminal book
The Death and Life of Great American Cities [
20] that traditional low-rise neighborhoods with front porches and stoops facilitate the “eyes on the street” natural surveillance, and hence promote security and community spirit [
40].
Similarly, Land H. Kendig and Bret C. Keast write in their book
Community Character: Principles for Design and Planning (2010) (pp. 85–86 [
41]): “At sixty feet (four to five stories), a building is ten times the height of a human; when a building reaches twenty stories, it is more than forty-four times human height. At this level, it is necessary to tilt one’s head back to see the skyline across the street”. Likewise, Jan Gehl elucidates that our “vertical” field of vision does not allow seeing upward unless we raise our heads. We also tend to bow our heads about 10 degrees when we walk, which makes it more difficult to perceive the high-rise environment. Horizontally, our cone of vision widens as we move away from tall buildings allowing us to see more of the skyline. Further, tall buildings not only dwarf human scale but also deprive streets of natural light, making them unattractive. Overall, a 1:1 ratio of street width to building height is desirable, and once we introduce tall buildings, they often alter this ratio drastically, creating urban canyon [
39].
2.4. Placelessness and the Public Realm
Similarly, because of their massive size and great height, tall buildings have often contributed to the problems of placelessness. In central business districts (CBDs), tall buildings frequently evoke the image of a nerve-racking, workaholic business environment. In addition, in residential areas they convey the perception of living in crowded apartments that are more akin to cages than living spaces. Inhumanely high towers often shatter the human scale by dwarfing nearby public spaces and buildings, particularly those of a historic character [
18]. People at the street level are unable to visually connect with them because they cannot see the whole building [
20]. People often become disoriented and feel lost in their midst, as if they were engulfed by canyons of skyscrapers. Also, the tenants of high-rises tend to lose sight of the pedestrian and social life of the street. Conversely, pedestrians often cannot see the decorative art and personalizing details, such as flowerpots in the upper-story windows, which bring a touch of humanity to these types of living structures [
39].
Speaking about Manhattan, Robert Freedman [
42] contrasts high-rise with low-rise neighborhoods in the same island. He explains that in walk-up apartment neighborhoods in Manhattan, a resident or a passerby would immediately feel a warm welcome not found in the towering, elevator-skyscrapers neighborhoods that proliferate through most of Manhattan. Freedman argues that vernacular brick, wood, and stone low-rise neighborhoods are more humane than glittering, steel-and-glass high-rise neighborhoods. He prolifically explains [
42]: “While walking, you have the sense that you ‘fit’. It’s not unlike retrieving your jacket after having mistakenly slipped into someone else’s that was several sizes too large. It just feels right”.
Moshe Safdie has also commented that tall building developments often hurt the public realm. He explained that at the street level, tall buildings have replaced small mom-and-pop shops, commonly found in traditional neighborhoods, with large, blank-walled facades [
43]. There are numerous tall building examples that support this view, including Westin Bonaventure Hotel, Los Angeles, CA, Hyatt Regency Hotel, Indianapolis, IN, the General Motors Renaissance Center, Detroit, MI, among others. Interestingly, it is not only tall building developments alter the feel and look of vernacular and traditional environments. New developments of shorter buildings could result with similar effects. However, the problem could be greater in tall buildings when they employ mega bases characterized by large and blank facades as well as lofty shafts as seen in the aforementioned examples.
According to Safdie, avant-garde architects strive to give new architectural forms or “object” buildings that pay little attention to human and social dimensions. These buildings disturb the urban social life. Towers function as singular, autonomous structures—some are experienced as lonely sculptural objects in the cityscape. They often do not contribute to the public realm because they are self-contained, introverted, and privatized. Planning, zoning, and urban design guidelines have neither observed nor regulated the great socio-economic interdependence of towers and the city. Overall, architects and planners have failed to deploy a tall building as an effective building block of cities. “Only powerful concepts for how earth meets tower can begin to bring about an urbanism in which the public realm is continuous, truly public, and possesses the appropriate environmental conditions” [
43].
Often, tall buildings require significant parking structures. Since it is costly to accommodate them underground, architects place them above ground, thereby taking away from the street social life and unstimulating the public realm. Their design is often insensible and damages the urban character. Parking garages above ground are a “street kill” because they disconnect social life of urban space, engender spatial disorders, and create “eyesores” in the city. Although this problem is not exclusive to tall buildings, it is most pronounced in this building typology because it requires greater parking spaces and larger parking garages.
Aesthetically, tall buildings often create contextual problems when placed near historic structures. As cities become denser and land values skyrocket, older historic structures are pressured to be demolished to make room for new taller buildings [
43]. In their paper titled “Tall Versus Old? The Role of Historic Preservation in the Context of Rapid Urban Growth”, Kate Ascher and Sabina Uffer illustrate this problem in three cities: New York City, Berlin, and Beijing. These cities face a challenge of accommodating new demand on space while preserving precious built heritage simultaneously. While Beijing has been engaged in razing large areas of its built heritage, New York City faces real estate pressure to make room for supertalls, and Berlin continues to debate which history is worth preserving [
44].
In particular, New York City has been witnessing an increasing pace in building tall and supertalls. Most of these buildings have been replacing low-rise 19th-century structures, despite preservationists’ objections, arguing that Midtown will soon reach “a tipping point in which the architectural mix of old and new is lost to a wash of sparkly glassy” (p. 108 [
44]). This problem accelerates as demand on space increases, and developable lots are progressively scarce in Manhattan Island. Overall, historic preservation issues are often contentious and require an interdisciplinary team to make sound decisions.
At the larger scale, tall buildings have contributed to the problem of placelessness by creating spatial chaos. Their massive size and great height make it difficult to blend into neighborhoods. In central business districts (CBDs), tall buildings evoke the image of a nerve-racking, workaholic business environment. Also, in residential areas, they convey the perception of living in crowded apartments that are more akin to cages than living spaces [
45]. The absence of an urban design vision that guides neighborhood and city developments have led to haphazard mushrooming of high-rises, evoking visual disorder. What makes the problem worse is that individual architects have been using high-rises as an opportunity to display their artistic talents at a mega scale, contributing to conflicting architectural styles in the same neighborhood.
Importantly, current practices of tall buildings are making cities around the world look alike. For example, downtown Melbourne looks similar to that of Pudong, Shanghai, Miami, or Dubai. The common shortfall of these skyscrapers is that design has not paid attention to local tradition, geography, and climate. In particular, the steel-and-glass tower, which invaded cities, has made them look homogeneous and similar, ignoring local identity and culture. “High-rise buildings and modern architecture generally are homogenizing our cities in the same way that Starbucks and McDonald’s are homogenizing the dining culture… I think this is something we need to fight against… so many of the buildings are about a sculpted form. They could almost be a perfume bottle or a vase. That has become an international style” [
46].
Recently, Richard Meier, one of America’s most respected architects, commented that New York is losing its character due to new disrespectful skyscrapers. He explained [
47], “There’s a scale to New York as there is a scale to London, and that’s what makes the city great…. New York has a quality to it and you have to respect the context”. Particularly, when planners plant a tall building in an isolated manner, it has the potential to exert a negative omnipresent visual impact citywide. For example, the 209-m (686-ft) tall, 58-story Tour de Montparnasse in Paris has negatively affected the urban character of the city to the extent that the city banned tall buildings for years.
Adam Caruso echoes a similar concern by explaining that cities suffer from haphazard developments of tall buildings. The lack of effective urban design regulations and architectural guidelines has turned cities into a “free for all”, according to Caruso [
48]. The key problem stems from the fact that the final say is for the one who pays for the project, the developer. Few countries, nevertheless, offer planners greater authorities and control over urban developments. For example, Germany gives the appointed city planners greater power to accept or reject a proposed building based on contextual fit, thereby preventing the emergence of chaotic urban design in the city [
34].
2.5. Fire Incidences
Tall buildings are prone to massive losses of lives and valuable properties caused by fire. High-rise buildings present several unique challenges not found in traditional low-rise buildings, including greater difficulties for a firefighter to access a smoldering high-rise building, longer egress times and distances, complex evacuation strategies, and smoke movement and fire control. Typical dangers at a fire incidence involve flame, smoke, heat, toxic gases, flashover, and backdraft explosions. However, the multiple floors of a high-rise building create the cumulative effect of needing greater numbers of firefighters to travel great vertical distances on stairs to evacuate the building.
Therefore, it takes much longer time for fighters to rescue tenants of high-rises than that of low-rises. An extended time of burning fire increases chances that flame and smoke reach tenants, thereby causing greater death to people and damage to the building. A prolonged rescue time also makes firefighters exhausted, whom bodies get exceedingly hot due to closeness to fire and heavy protective gears and masks they wear. Further, in disastrous fires, sprinkler systems and fire elevators can malfunction [
49].
Despite advances in fire codes, numerous high-rise buildings continue to be ill equipped. High-rises, particularly in the developing world, lack effective fire safety standards, fire prevention, and emergency action plans. In 2009, a fierce blaze engulfed the 31-story hotel and cultural center, which is part of the China Central Television’s headquarters (CCTV) in Beijing [
50]. Designed by the renowned Dutch architect Rem Koolhaas, the fire happened few months before completion. It was difficult for firefighters to control fire because their equipment was incapable of fighting fire above the 20th floor. Luckily, the building was unoccupied; therefore, there were no casualties. However, a fire that burned an apartment building in Shanghai resulted in killing 48 and injuring 90 residents in 2010 [
51]. In the same year, a fire hit Carlton Towers in Bangalore, a neighborhood in Delhi, India, which led to the death of nine and the injury of 70 residents [
52]. After the incidence, authorities investigated fire safety in the city and found that most high-rise buildings did not meet fire safety standards.
On the New Year’s Eve of 2016, an intense fire engulfed the 63-story Address Hotel in Dubai, UAE [
53]. An electrical short circuit caused a spark that triggered the blaze. Likewise, in 2015, the 86-story Torch building also in Dubai experienced a fire in its upper floors [
54]. It took considerable time to evacuate this residential tower due to its exceptional height. In response to these fire incidences, Dubai has enacted new buildings’ regulations requiring less flammable exterior cladding, as well as specific procedures for installation and maintenance. It also debuted jetpack-equipped firefighters in a bid to tackle skyscraper fires swiftly by avoiding traffic jams on the ground.
When construction completed, The Torch was the world’s tallest residential tower. However, other residential supertalls completed recently have snatched that title. For example, global developers have built several new taller residential towers in Dubai, including the:
413-m (1356-ft), 101-story Princess Tower,
392-m (1287-ft), 88-story 23 Marina, and
380-m (1248-ft), 87-story Elite Residence.
In 2015, the New York City, however, snatched the world’s tallest residential tower title from Dubai by building the 426 m (1396 ft), 85-story 432 Park Avenue, designed by Rafael Viñoly.
Most recently, in June 2017, a devastating fire hit the 24-story Grenfell Tower causing the death of nearly 80 and injury of additional dozens of its 600 residents as well as the destruction of the entire building, despite of the deployment of 40 fire engines and 200 firefighters—fire-fighting equipment did not reach beyond the 11th floor. Importantly, the building’s owner has fitted combustible insulation boards (Celotex RS500 polyisocyanurate foam core (PIR)) behind the cladding during a recent refurbishment, which accelerated fire spread. Moreover, these boards have released cyanide gas that contributed to the deaths of some of the victims. Richard Hull, a leading professor of chemistry and fire science, commented, “Unlike ships, trains, or aircraft, where fire toxicity is regulated because it is accepted that escape may not be possible, the UK and most of Europe have no regulations on the toxicity of fire smoke from construction products, even though escape from a high-rise building may be equally impossible” [
55]. As such, faulty materials as well as bribery have exacerbated the fire problem in this building.
Furthermore, building regulations when the tower was built in the 1970s did not require the installation of sprinkler systems (internal and external), which could have minimized fire damage. Until today, most cities do not require buildings with combustible cladding to integrate external sprinklers. Additionally, London’s fire regulations require tower blocks to have merely one staircase. Certainly, a second staircase could have eased tenants’ escape from the building.
Fires in high-rises threaten the lives of residents and firefighters alike. For example, high-rises incorporate tall shafts such as elevator shafts, smoke shafts, utility wire and plumbing shafts as well as package and mail and garbage chutes. Usually, safeguards such as railings, gypsum block walls, self-closing doors, and trap doors prevent occupants from falling into these vertical elements.
Nevertheless, a fire can destroy these safeguards, and in a dark or smoke-filled environment, firefighters can fall to their deaths in these shafts. Research has documented cases where fire has killed and injured firefighters in high-rise buildings such as the Empire State Building and 1 New York Plaza in New York City and One Meridian Plaza fire in Philadelphia. Further, during the fire, chunks of glass and metal of tall buildings may rain down on pedestrians on the ground [
49].
Overall, security and safety systems are costly, and some are less effective. For example, helipads are costly and often helpless because helicopters take a considerable time to land, load people, and take off. They take a small number of a skyscraper’s occupants at a time. Further, helicopter pilots are often extremely hesitant to land on a burning building, fearing that the helicopter may catch fire as blazes and smoke swiftly ascend.
Even if a pilot decides to take a risk and land on the rooftop, the rising heat and smoke from the fire may jostle and destabilize the helicopter, thereby complicating the landing process and preventing people from boarding the helicopter. Research revealed that if the World Trade Center rooftops had been accessible (the helipad fell into disuse), helicopters could not have landed because of the heat and smoke. Consequently, rarely used helipads may enhance the perception of safety; however, they have a limited role to play [
56].
The helipad’s integration in tall buildings limits skyline design. For example, the skyline of the City of Los Angeles, CA, has suffered from “flatness” dictated by local zoning codes that required that all buildings 75 ft (22 m) and taller integrate helipads in their roofs. The city enacted the law in 1974 after two deadly skyscraper fires in Brazil. However, authorities have canceled this law recently after discerning that helipads had been of little use.
Also, the helipad’s problem in limiting design for rooftops was apparent in the one-kilometer-tall (3280-foot-tall) Jeddah Tower, currently under construction in Jeddah, Saudi Arabia. The architects proposed a protruding helipad near the top of the pointy tower. Nonetheless, helicopter pilots pointed out that they would not feel comfortable landing there because they feared tight space and potentially high winds could cause them to hit the tower. Consequently, the architects converted the proposed 7500-square-foot (697-square-meter) helipad to an outdoor terrace instead, known as the “sky terrace” that will overlook the Red Sea [
56].
2.7. Window Cleaning, Repair, and Maintenance
Daily activities carried out to repair tall buildings and to clean their windows threatens the lives of workers. People often take the issue of window cleaning of skyscrapers lightly; however, it continues to be a frequent cause of the death of workers. Cleaning crews perform tasks manually by descending the height of the building from the roof to the ground floor while hanging on ropes and carrying water buckets and cleaning tools. Workers go down floor-by-floor, but some get dizzy and fall off while others bounce into walls and windows because of forceful wind.
Cleaning mechanical systems may fail. For example, two cleaning workers were stranded in their scaffold as one of its two ropes slacked while cleaning the exterior windows of the recently completed One World Trade Center. The scaffold flipped over almost vertically, and workers waited in place for nearly two hours for rescue [
58]. By using a diamond saw, the Fire Department of the City of New York (FDNY) cut through the glass panel from inside the building and rescued them. Though successful, the process was risky since cutting a hole in the window at a higher altitude could have created a powerful wind tunnel.
Nevertheless, cleaning skyscrapers’ windows is a daunting task, particularly for larger buildings. For example, it takes 36 window cleaners four months to clean the 26,000 windows of Burj Khalifa [
59]. Importantly, there are issues of labor abuse since most of these workers are immigrants and employers deprive them of their social rights, safety, security, and health benefits. For example, most of the window cleaners in Hong Kong are immigrants from countries of Philippines and Indonesia. In New York City, the majority of window cleaners are immigrants from South America [
59].
Unfortunately, we are technologically far from having robots replacing cleaning workers. Machines cannot clean windows as well as cleaning workers do. Unmanned cleaning machines tend to leave dirt, stances, spots, and gray areas around the rim of the window, for example. These machines also cannot reach building corners well, and they have difficulties to work with facades that feature treatments and articulations, recessed windows, metallic decorations, and cantilevered elements. We tend to underestimate the importance of having a clean and clear glass. Nevertheless, buildings’ tenants who pay a high price for views do value clean windows.
What makes the problem worse is that architects increasingly design complex shapes for skyscrapers, making it harder for a machine to do the job. A robot will not be able to maneuver complex shapes to reach each facet of the building. Also, buildings’ owners are clinging on traditional rope-and-scaffold systems because they need them for purposes other than cleaning windows, including maintenance and repair, for example for repairing facades, balconies, and broken windows. Regardless, it is pathetic that we can develop technology to put a man or women on the moon, but we are incapable or unwilling to develop technology that saves workers’ lives, window cleaners, and construction crews. It is sad that skyscraper design does not pay adequate attention to these problems. Architects continue to focus on inventing new forms and shapes, not on saving lives. The window-washing problem should be the first not the last to address.
Further, window cracking and breaking are common problems in supertall buildings. Indeed, glass ages and weakens over time and any deficiencies in manufacturing or installation could lead to cracks or breakups under wind pressure. For example, Willis Tower (formerly Sears Tower) in Chicago has experienced several incidences where under forceful wind some windows in the upper floors were shattered. On 22 February 1998, winds gusting to 56 miles an hour broke and cracked 90 panes of the Willis Tower [
60]. Debris fell on sidewalks, damaged properties, and hurt pedestrians. For safety considerations, police blocked streets and rerouted traffic, causing inconveniences and traffic congestion in adjacent neighborhoods.
2.8. Construction Workers
Constructing tall buildings, particularly supertall, may entail the death and injury of construction workers. Unfortunately, construction activities continue to rely on labors who perform tasks manually. For example, façade assembly and exterior cladding rely on labors so that they manually grab panels from cranes and fixate them in assigned places. Construction workers repeat this process for each panel individually until the façade is complete. The process is tedious as panels are in thousands; for example, Burj Khalifa contains 26,000 glass panels [
59]. The assemblage task is most challenging in upper floors where the wind becomes more powerful and in the process, some workers fall and die. Tragic cases also happen during similar tasks, for example assembling structural systems.
Construction workers bear a risk in building skyscrapers. A recent online article by the
For Construction Pros reports the following incidences in constructing skyscrapers [
61]: five deaths for the Empire State Building, 60 deaths for the 1970s World Trade Center, five deaths for the Sears Tower; and six deaths for the Las Vegas’s CityCenter project. Also, in 2016, a construction worker fell to his death from the 53rd floor of the Wilshire Grand tower in downtown Los Angeles [
62], and in 2017, in Manhattan, two workers fell about 35 feet from an external elevator shaft, killing one and injuring the other. Further in Manhattan and in the same year, a construction worker fell from the 29th floor to his death [
63].
Regrettably, automating the entire construction process of skyscrapers is still far from reality. Overall, specialized labors and high precision work are essential in all construction activities of skyscrapers [
64]. As architects design more complex forms and shapes of buildings (including tall ones), construction workers face greater risks. However, it is interesting to note that the greater death of construction workers occur in constructing canals, tunnels, and railroads not buildings [
61].