Building from the ground up towards sustainability

Building from the ground up towards sustainability

Derive maximum benefit from limited space, writes Sachin Sandhir

On January 4, 2010 the world looked on in awe as Dubai unveiled the world’s tallest building – the ‘Burj Khalifa’. This mega structure revealing its official height at 828 meters amidst thousands of onlookers is a testimony to not only the acceptance but also the viability of tall structures.
With ‘Burj Khalifa’ having set multiple records as the tallest free-standing structure, building with the highest number of stories, highest occupied floor and outdoor observation deck, elevator with the longest travel distance, and tallest service elevator - one school of thought continues to believe that tall buildings around the world are created mainly as a symbol of vision, determination, innovation and achievement.
Other apprehensions that co-exist with the number of tall buildings mushrooming and changing skylines around the world are the impacts that these structures have socially and economically on surrounding cities. These factors however, acquire a whole new meaning, particularly in developing countries like India, where builders are frequently confronted with challenges inherent to capacity constraints, poor infrastructure, availability of land, and high costs.
Concerns on these issues are further compounded by the growing global pressure to reduce carbon footprint while creating sustainable habitats. Therefore, the onus has now shifted to the built environment to ensure that new structures reduce energy consumption and increase efficiency through the use of renewable energy sources, innovative and green construction materials and technologies, recycling and waste management systems etc. But whether tall buildings can actually make use of these methodologies and be sustainable is a question that remains debateable.
By some standards and estimations buildings are classified as high-rises when their heights range from 23-150 meters, while anything above 150 meters might be classified as a skyscraper. Therefore, the argument to have a definitive rationale behind the creation of an exceptionally tall building persists. A number of parameters and factors such as relationship of the structure with the topography and transport infrastructure, architectural quality, and contribution that the development lends to internal and external public spaces must be evaluated and considered.
Having established this premise, it is also essential to realise that in some cases, there is no alternative but to build tall, as is the case of Mumbai city and several other metropolis’ around the world. In Mumbai, where availability and access to land is at a premium, it is essential that maximum economic benefit be derived from limited space. In such cases high-rise buildings hold the potential for larger real estate development, while being financially viable.
Buildings conceived for mixed use for residential, recreational and commercial purposes can actually be energy efficient as they ease pressure on land, while freeing up the surrounding area for creation of infrastructural facilities and landscaping purposes. Additionally, with varied services and amenities offered potentially under ‘one roof’, there is an ease in urban sprawl with a larger segment of population serviced by existing public transport and infrastructure. In fact it is surprising, that concrete jungles such as New York and Manhattan can serve as prime examples of tall cities gaining energy efficiency and having low carbon foot prints.
However, on the very basis of their magnitude tall buildings are more often than not considered unsustainable. Strong materials such as steel and cement with high intensities of embodied energy are required to create the skeletal framework and lay the foundation for long lasting structures. With hundreds to thousands of people being serviced through the facility, there is extensive use of energy for heating/cooling purposes, lighting, waste management, mobility through elevators etc.
Also, while all buildings have ‘front-end’ energy costs associated with them, the ones with bioclimatic design and micro-generation have higher embodied costs than others. These cost factors associated with sustainability in tandem with the long payback periods and existing high costs involved in constructing high-rises are deterrents to developers, especially in the Indian context.
Additionally, skyscraper construction and design have to deal with complex challenges of balancing construction management, engineering and financial considerations. The structural design is imperative and should be strong enough to support the weight of the inhabitants and at the same time be earthquake, wind and fire resistant. Citing an example of the ‘Burj-Khalifa’, these factors have been given utmost priority with design greatly influenced by traditional Islamic patterns and the hymenocallis desert flower to reduce wind pressure on the structure, having undergone over 40 wind tunnel tests prior to its opening. Additionally, all design considerations for the structure were in consideration to the 12,000 people who will either live or work in the tower.
In India however, the enforcement of stricter norms for structural safety, environmental factors and disaster management still pose a challenge. With height restrictions being waived in several cities by local development authorities and the Civil Aviation and Airport Authorities recently giving clearances for construction of buildings up to 300 metres around a radius of 20 km from airports, issues related to fire safety in high-rises continue to remain a cause of concern.
In spite of having 32 standards for fire fighting and another 132 standards in place for fire fighting equipment as mentioned by the Bureau of Indian Standards, fire engines in the country are capable of reaching only up to the 21st floor in most cases. This fact highlights the dire need for a systemic change in the approach to management and operations of tall buildings in the country.
But progressively, vertical development is being touted as a promising prospect to overcome India’s housing woes. With lifecycle assessment of buildings and construction materials now gaining credence, embodied energy can be reduced to quite a large extent in high-rises with repetitive floor plans and large areas of façade. However, with limited FSI norms stipulating height restrictions not too many high-rise apartments are cropping up. Therefore, there is growing industry pressure to relax these norms for India to go the vertical way.
As tall buildings become an inevitable form and integral part of our contemporary landscape, it is necessary for development to be pursued in conjunction with emerging policies on sustainability and climate change.

Sachin Sandhir is Managing Director & Country Head, RICS India. He can be contacted at ssandhir@rics.org