Tall buildings are large, organized structures that enable a wide range of economic activities by diverse populations. They house stacked "neighborhoods"where access to vertical transportation, green space, sunlight, and fresh air directly impacts resident quality of life, health, and productivity. Recognizing this, why aren't there more public spaces in tall buildings?
Value As with all buildings, perceptions of "value" drive investment and design decisions. In a world focused on first costs, maximum efficiency, and leasable space, communal space has long been perceived as something to minimize. However, with today's changing marketplace and expectations for collaborative workplace design, highly-amenitized residential products, and competitive sale and leasing environments, 20th-century definitions of value are being challenged to envision and deliver new, 21 st-century products.
Public spaces in tall buildings are typically highly-programmed lower-level or podium spaces, and upper-level sky lobbies, sky gardens, amenity floors, and observation experiences. However, these spaces are usually only semi-public, as they are limited to building occupants and paying ticket holders. As city populations grow, it may become increasingly important to not only provide great public spaces around buildings, but also in upper levels of tall buildings with public access and programming.
The provision of public spaces in tall buildings is also anticipated to grow in significance as a way to gain wider community acceptance of often-controversial development projects. Communities and authorities could be more willing to receive such developments when access is expanded to broader populations. However, we must assure that such spaces are not isolated Islands that are difficult to access.
Perhaps such concepts are most applicable to cities with significant grade differentials, such as Hong Kong, and established cultures of multi-level access and building interconnectivity. Such spaces could be used to receive people, link to public transportation, and provide one-of-a-kind experiences that are a source of civic pride.
Health, Well Being, and Productivity The mental and physical benefits of higher indoor environmental quality, access to open space, and human interaction are well documented, particularly in the healthcare and education sectors. In the workplace, access to open space demonstratively increases employee performance while reducing absenteeism. Public spaces in tall buildings could contribute to the overall health, well-being, and productivity of their occupants.
Given today's expectations that employees be imaginative, and no longer simply industrious, public spaces that engender social exchange and nurture mental and physical health are becoming increasingly important. Such spaces could enhance collaboration and community building within organizations. It is reasonable to anticipate a market-supported shift in values for tall building public space design.
Technical Challenges If more substantive public spaces are to be integrated into all buildings, technical issues related to cost, security, and life safety must be addressed. Although challenging, these issues present opportunities for innovation and the evolution of tall building design.
To be viable, public spaces must balance cost and income. Except for observation floors, public spaces have not yet reliably generated income for owners and operators. Since other types of public use are not yet standard at height in tall buildings, there is an element of untested market demand.
Security and liability issues must also be addressed, as the lines between the operation of public spaces versus host building responsibilities can become blurred. Clear operational structures must regulate hours of operation, security protocols, and maintenance.
From a life-safety point of view, high occupancies associated with public spaces on higher floors of tall structures have a significant impact on vertical transportation and exiting stair design. This may be the primary reason that most public spaces have been located on lower floors thus far.
The above conveys the essence of discussions we are having with developers and municipalities around the world regarding the integration of public space into tall buildings. Hopefully they raise questions and frame design and operational issues that can be addressed collaboratively, with particular focus on the urban habitat aspect of tall building environments.