Offices have now moved away from the conventional idea of a standard brick-and-mortar building to a new, modern and sustainable ecosystem that prioritises worker wellness and safety while also scoring high on environmental standards.The building of Karnataka Power Corporation Ltd (KPCL)in Bengaluru sets a new benchmark of sustainability in office design and becomes only the second government building to achieve the Platinum Rating Certification under IGBC NC (Indian Green Building Council) for sustainable design. Studio Decode was the architectural firm for this project and as Meghana Dutta, Principal Architect, shares “The brief given to us for the design of the building by the client was minimal. We had to design a sustainable building that could set an example for the other private and public developments in Karnataka. It had to be simple, cost-effective and enhance the experience of working for occupants.” She elaborates upon the various green features of the building that helped it to achieve the certification.

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Design approach

The design of the building evolved from an effort to devise a highly efficient building envelope that not only performed climatically but integrated the landscape at multiple levels to enhance the user experience. The spaceswere also organised and layered to bring in comfort and optimisation of functionality. Thedouble-height landscape volume in the second and third floor has been designed to become a space that can bring on chance interactions and serve as a community outdoor space and sanctuary in an otherwise built structurethat forces one to be indoors. This space and other outdoor areas lendto the character and identity of the building, which is about creating a building language where the flow of spaces between the built and the unbuilt at multiple locations and levels are key aspects of design.

Sustainabledesign concepts

Key sustainable aspects that formed the root of the design were simple, common sense design aspects such as natural daylight, natural ventilation, rainwater harvesting, stormwater management, solar energy, landscaping using native plants, use of sustainable and renewable building materials, low VOC content in materials specified, treatment of black and grey water and reuse of the same for flushing, handicap accessibility, braille buttons on the elevator, low partition walls for office workstations to not cut off vision to the outside and the use of materials onsite that allow for groundwater recharge.

The challenges

The site is located in the dense CBD area with its longer sides along the east-west axis and thus posed many design challenges in promoting a sustainable approach to the design of the building. The façade of the building adopts a grid fin system that was carefully simulated and then sized to cut the low sun angles of the east and west exposures. The building has been designed to maximise natural light to all corners of the floor plate. Theair-conditioning provided need not be used as the interiors stay cool naturally with cross-ventilation factored into the design. Notable features
The project has a building management system to monitor and control the air-conditioning, lighting, fresh air, elevator and Co2 control and monitoring systems. CO2 sensors have been installed in return air ducts to maintain a differential CO2 level of a maximum 530 ppm in all regularly occupied areas of the project. Daylight simulation has been undertaken to show that over 75 per cent of regularly occupied areas achieve daylight illuminance levels above 110 lux in clear sky conditions.

Electric charging points have been provided to encourage clean energy usage. Over 90 per cent of parking is provided in the basement. The parking provided on ground has been planned to get shade from the trees that have been planted. The exposed area of the roof that is not covered with solar panels uses reflective paint to reflect heat back and reduce heat transfer into the building from the roof.All exterior lights used do not emit light upwards to the sky, thus avoiding night sky pollution. Sub meters measure energy consumption from the plumbing system, exterior lighting, air-conditioning, STP, ventilation and DG set.

Special focus has been given to waste collection as well, with separate collection bins for dry and waste installed at every floor level. Organic waste and e-waste collection is also provided at every floor and the main central collection is provided at the basement.

Saving water

The use of water-efficient plumbing fixtures has enabled 32.9 per cent of water savings in comparison to standard buildings – from 5,016kl/year to 3,365kl/year. A total of 697sqm of landscape area has been provided, of which 67 per centhas been planted with drought-resistant plants. Drip irrigation has been provided for over 85 per cent of the area and 100 per cent of wastewater is treated and reused for flushing and the landscape. Water meters have been installed to monitor borewell water consumption, treated wastewater consumption and landscaping water consumption.

Materials used

Doors, paints, plumbing fixtures, cement and Gyproc plasterboard with GreenPro certification have been used in this project. Local materials and materials with high recycled content were specified wherever possible. Low VOC paint and coatings and composite wood with no urea formaldehyde resins have been used in the project.

Energy savings

The project has achieved energy cost savings of 47.1 per cent over baseline case buildings. This was possible owing to the following factors: The specification of wall materials helps to reduce heat gain. Use of natural daylight and efficient glazing reduces the use of artificial light, heat emitted from bulbs is reduced and thus the AC load is reduced. The use of occupancy sensors in all spaces ensures there is no wastage of electricity. The roof insulation has helped reduce heat gain from the roof, while the use of PV helps to generate 12.3 per cent of total required energy. However,as the AC is not being used, in reality the energy savings would be much higher than 47.1per cent.

At the time of certification, IGBC also informed the client that the building scored high in attaining internal climatic comfort as a result of simple design solutions and less dependence on artificial or mechanical systems.