The building envelope is one of the most important exterior elements for building functionality. Façade is an important component that helps to improve the architectural aesthetics of the building. Glass façades for office complexes and condominium towers are nowadays becoming very popular in Metro and other major cities in India. However, proliferation of glass façades and their illogical and unscientific use may cause irreparable ecological loss.
Several studies have shown that glass façades are nothing but death traps for birds causing biologically significant losses to the bird species. According to one study, annual bird fatalities in North America from window and glass façades collisions may be as high as 1 billion birds per year or 1-5% of all birds.
While the facts relating to bird casualties due to glass façades are staggering, the solutions are within reach. The majority of these deaths are foreseeable and avoidable. Simple measures like window treatments, lighting design, and lighting operation can avoid such casualties. Opaque or translucent films, decals, dot patterns, shades, mesh screens even nets can avoid casualties but either they increase cost or reduce aesthetics of the buildings.
Apart from bird lovers, glass facade buildings also face the ire of environmentalists and conservationists. These glass façade buildings are also known for energy guzzling capacity as they trap heat thus requiring more power to cool them. Buildings with glass skin trap heat and in a tropical country like ours keep the inside temperature hot and expelling this trapped heat is a difficult and expensive task as there is not much scope for natural ventilation in a glass building. So, there is nothing wrong if environmentalists are vehemently opposing rampant use of glass facades in buildings in our country.
It is in this light that one should welcome the new development control regulations (DCR) under Mumbai’s development plan (DP)which discourages glass façades in city’s buildings. According to the new DCR if builders continue to use the glass facade material, which they are barred from using, then the area between the glass façade and the wall behind it will be counted under floor space index (FSI). This rule can act as deterrent for builders not to go for glass façades in city’s buildings.
Remember air conditioners are one of the largest consumers of energy in the world and also the largest contributors to global warming. A recent survey has found that energy consumption by air conditioners is expected to tripple by 2050. Increased use of glass façades will only add to the nation’s energy bill. So, sensible use of glass on the building envelopes is warranted. Once a prominent city like Mumbai brings out a rule to discourage its use in façades it may not take much time for other cities to follow Mumbai’s example.
The United States Green Building Council which encourages the creation of environmentally conscious buildings also has various parameters for use of glass in façades. Its environmental certification process, called LEED has set out various norms for bird safety and energy consumption which are slowly and gradually becoming universal principles. In the meantime, local governments through various laws, proper education and incentives should also create awareness about sustainable building practices.
Hope one day people start rising against all-glass building just as they do for wearing a fur coat.