ONGC's recently completed commercial building in Dehradun looks forward to being one of the first government buildings to receive the IGBC LEED Platinum rating.
When power, water, air and materials came together in an innovative and sustainable manner on a brownfield site, the outcome was ONGC's commercial office in Dehradun. Located in the heart of the city, the building has been designed and built according to IGBC's LEED Platinum rating. A first of its kind in the country in terms of design, its USP is a green roof that spreads over 1.5 acre. The idea was to create an impression of the surrounding area being lifted up and the office building placed underneath it. Designed for two towers with a basement + ground + four floors, the wide upper atrium incorporates the reception and waiting area and the lower atrium opens up to an outdoor deck that steps down to a public plaza. "From site selection to ensuring green areas are not harmed or demolished, everything has been taken care of," says JP Rao, Director-Corporate Marketing Strategy (India-Construction), Shapoorji Pallonji and Co. He elaborates upon the building's green features in conversation with SHRIYAL SETHUMADHAVAN.
Step A
While we are the design and build entity for the project, Architect Hafeez Contractor is the architectural firm involved. And while ONGC involved CII as their consultant, Spectral was our green consultant. Initially, ONGC had mentioned all the requirements of a green building in the form of a proposal document. The document clearly mentioned their vision of a LEED Platinum-rated commercial building in their campus area in Dehradun.
A client's briefing session was organised through a workshop, attended by the consultant, architect and our own design team, and the complete proposal - especially from the green building perspective - was discussed. For instance, there was a mention of old structures that would have to be demolished but, at the same time, the client also mentioned that all salvage materials procured needed to be used in the new construction. Following this, a complete monitoring process was followed to understand where would we stack which material and how would we obtain the certification.
The living roof
A major part of the research went into the green roof. The first layer is of a reinforced concrete slab. This was a real challenge as the building gains different shapes in three different directions. The second stage involved waterproofing and then we put in the soil. Retaining the soil was another challenge owing to the steep slopes and it is was important to arrest soil erosion. We tested some suppliers particularly to understand if the idea was workable. We did a lot of leakage tests after waterproofing; after laying the soil, small blocks were made to retain the soil. We then started planting the grass. The next challenge was to maintain the green grass throughout the year. So based on the orientation and sun's direction, the density of the grass was selected. A water and irrigation system has been fitted to provide water throughout the year. This living roof also acts as insulation for the building in term of reducing heat load.
The lungs
Skylight covers have been conceived as the lungs of this living roof. They breathe daylight into various levels of the office floors. Around 30 to 35 per cent of the roof area has these openings. Further, while the skylight cover is on the top of the roof, windows are on the fatades.
For this, the method of peeling has been adopted to reveal three entities of the office building, namely the main entrance, the lower atrium and the chairman and managing director's cabin. So, in a normal scenario, where buildings have windows, here it feels like a part of the roof is peeled off.
Saving power
To reduce the electricity requirement, solar panels with a capacity of 108 kW have been effectively used, meeting 7.5 per cent of the building's total annual energy requirement. A solar water heating system and LED and intelligent light fixtures with sensors have been installed.
Further, the HVAC on Under Floor Ventilation system (UFAD) is combined with an integrated building management system (IBMS) to manage the HVAC, lighting, and power control in the building. Further, CO and CO2 sensors have been fitted to detect the CO and CO2 levels in a particular room or area. So for instance, if there is no occupancy within the room, the air-conditioning and lights automatically go off. Moreover, the U-value of the roof has been kept low. Features such as the terrace garden have been included in the building design to provide added insulation for the roof. The 'evapotranspiration' effect owing to the terrace garden also contributes to keeping the building cool during summers. With a per sq ft electricity consumption of 0.51 W, which is very low as against the normal 1 W, these features together help conserve around 45.5 per cent of energy.
Handling air
As far as the indoor environment is concerned, we have used water-cooled chillers over air-cooled chillers.
The chiller pulls the air inside and the water is then cooled to a particular temperature. This further helps the air cool, which is then passed through another duct in to the air-conditioning. This is done through heat recovery wheels, which are basically used for chillers and air-handling units. Also, the chilled water pump system with variable flow pumping is used. The electricity consumption of the pumps in the primary chilled water loops can thus be varied.
Every drop matters
Low flow rate fixtures help control the usage of water. Considering the green roof spread, we also calculated the catchment area and then decided the direction in which we should have the rainwater harvesting pit. The idea is to not let the complete rainwater go out to the nalas and other streams, so the groundwater level is raised. Apart from that, in order to save water, we have put up effluent treatment plants (ETPs) or sewage treatment plants (STPs). Water is treated in the ETP and used for horticulture through the sprinkler system. All these features together contribute to saving a minimum of around 20 per cent of water.
Materials matter
We have ensured that basic resources like cement or gypsum boards have been sourced from within the given periphery. Recyclable materials have been used and manufacturers, especially for glass and carpets (CRI certified), have provided a certificate stating that the material is recyclable. We have also saved a lot of wastage like concrete. If you save a 1-m cube of concrete from getting wasted, you save over 300 kg of CO2 emission to the atmosphere. So we have arrested the wastage in the concrete and used it for casting curves for the roads. Also, areas of the roof have been glazed for the light to come in. Instead of shading devices, double-skinned glass glazing has been used as it absorbs less heat and transmits maximum light. There are two layers of the glass here with a thin cavity in between that acts as a conductor of heat. Sourced specially from China, it had to be tailor-made owing to the design.
Cost matters
While the initial investment may be slightly more in a green building compared to the expenses involved in a non-green building, this pays off in the long run. For instance, the total construction cost (excluding land cost) for ONGC's building amounted to about Rs 130 crore, with a payback period of about seven-and-a-half years. One challenge we faced was that when the local people got to know of our requirement of local materials, they started imposing their monopoly. So if the cost of a material was X, they made it X+2. However, in such a scenario, we tried to compensate this extra amount in other areas without sacrificing on the quality. The last lap While ONGC will soon approach IGBC with the final submission, there could be some modifications required post auditing. To avoid the same, we thoroughly involved the green consultant throughout the design and construction stage.
Project details:
Project: Construction of a green office building in Dehradun
Client: ONGC
Date of completion: May 2013
Area: 187,280 sq ft
Status of LEED rating: Final submission to IGBC by July-end
Design-Builder: Shapoorji Pallonji. Tel: 022-6749 0000. Fax: 022-6633 8176. Website: www.shapoorji.in
Architect: Architect Hafeez
Contractor. Tel: 022-2266 1920. Fax: 022-2266 4737. E-mail: hr@hcontractor.com Website: www.hafeezcontractor.com
LEED consultant: Spectral Services Consultant (AECOM). Tel: 0120-404 9000. Fax: 0120-404 9001. E-mail: info@spectralservices.net Website: www.spectralservices.net
Structural consultant: Epicons Consultants. Tel: 022-2421 6215. E-mail: epiconsd@mtnl.net.in Website: www.epicons.co.in
Roofing vendor: EcoGreen Landscape Technologies India. Tel: 020-2721 9275. E-mail: info@eltindia.com Website: www.eltindia.com
Nilabh Nagar, Senior Associate, Architect Hafeez Contractor, on the project. "ONGC wished for a Platinum-rated commercial building that would suit its current campus area in Dehradun. Taking inspiration from that landscape, Hafeez proposed the idea of merging the building as part of the entire landscape of the 70-acre campus. Also, we did not want to disturb the tree growth in the centre and surrounding areas. One interesting concept is the under floor air-conditioning, as it keeps the ceiling free and is more efficient. Further, the building has been designed for the green roof that meets the thermal criteria of roofing as per Platinum rating norms. Hence, heat does not transmit to the office level. In terms of local materials, we had to ensure that it was sourced from within a 500-km radius. Also, the carpet and ceiling materials, for example, have a fairly high amount of recycled content. And even the wood used in this project has been certified as it comes from recycled forest. While MDF and particle boards with high recycle content have been used in workstations, the blocks and concrete used have high fly-ash content."
