India’s urban skyline is constantly changing with the increasing construction of tall buildings to cater to the growing population. Tall buildings present special challenges in design and construction as well as in the choice of materials for the interiors. Sometimes, the availability (or the contrary) of a certain material influences the design. Sometimes, the design drives the choice of materials. CW engaged with developers with tall building expertise and consultants to determine what must be considered in material selection to ensure that the building has longevity,is environment-friendly, operates efficiently and requires minimal maintenance. Construction materials In the construction of tall buildings, tower cranes and concrete pumps play a crucial role. “Potain, Liebherr and ACE tower cranes are reliable and capable of superior load management,” says Vaibhav Kulkarni, General Manager, Projects, Aaryan Devcon. “Putzmeister high-pressure concrete pumps have excellent pumping capacity and durability, both of which are essential to deliver concrete to great heights with precision. Putzmeister and Schwing Stetter concrete pumps are reliable and efficient in handling high-viscosity concrete mixes. Additionally, boom placers allow the precise pouring of concrete and are very efficient in high-rise construction.” At present, Godrej Properties is nearing the completion of the construction of Godrej Meridien’s Tower 3 and Godrej Meadows. For these tall buildings as well as other projects, Godrej Properties opts for Potain, Liebherr, Spartan or equivalent tower cranes, and TATA, SAIL, JSW or equivalent steel. “Our choice of construction equipment and materials, and materials used to finish the interiors, tends to lean towards top brands with best-in-class manufacturing standards and high-level safety standards,” explains Vikas Singhal, Chief Operating Officer, Godrej Properties. “We also look for providers who have adopted better raw material sourcing and manufacturing processes than the industry average, who provide best-in-class quality and after-sales services, and whose historic performance is better than the industry average, as all this translates into fewer defects during usage.” “Tridhaatu Realty has opted for ACE tower cranes for Tridhaatu Aranya, M50 to M30 grades of concrete and Schwing Stetter concreting equipment, and FE 500/ 500D TMT steel,” says Dhananjay Sandu, Co-Founder and Managing Director, Tridhaatu Realty. “Zoomlion tower cranes and Guardian Steel are the Prescon Group’s choice for Prescon Midtown Bay,” shares Vedanshu Kedia, Director, Prescon Group. “Potain, ACE, Zoomlion and other tower cranes are the Siddha Group’s choice for Siddha Seabrook,” adds Samyak Jain, Director Siddha Group. “We’re sourcing concrete and concrete equipment from Ashoka Buildcon, RDC, Jallan Concrete, etc, and steel from companies like Bhagwati Steel, MITC and Regency.” Façades and fenestrations While many external façade material options are available, for high-rise buildings, this choice is controlled by the need for the material to be lightweight, highly durable and relatively maintenance-free, observes Rajan Govind, Director, Facade Specialist, BES Consultants. “Consequently, glass and metal are dominating facade materials for high-rise buildings.” In glass façades, the widely adopted types for high-rise buildings are high-performance, laminated double glazed units (DGU) as these enhance occupant comfort and ensure energy-efficiency, he continues. “Oversized or jumbo size panels in elegant and modern designs are the latest trend for creating almost transparent façades.” In high-rises, doors and windows must satisfy several aspects such as safety, functionality, aesthetics, and so on, adds Govind. “Wider and taller windows are highly desirable for a better user experience.” Having said that, he notes that the need to meet multifunctional requirements is a challenge for designers. Sometimes, clients must balance their need for aesthetics with the available options. “We opt for JSW or equivalent window sections and Saint Gobain, Asahi or equivalent glass,” says Singhal. While Schueco system windows is the preferred brand for Tridhaatu Aranya, Sejal Glass is the preferred brand for the glass façade, and Tata and Fenesta for the doors and windows of Siddha Seabrook. “For Prescon Midtown Bay, the choice of façade is Everest and the doors and windows are from Vibrant Doors,” says Kedia. Electricals & backups Electrical switches are increasingly being seen as a key interior material for standing out, and to this end, VS Kukreja, Founder, VS Kukreja & Associates, points out that aesthetics is a desirable feature of switches (besides brand and cost). “With an eye on maintenance, also consider if a replacement warranty is on offer,” he says. Godrej’s tallest towers feature Anchor, Schneider, Panasonic or equivalent electricals while the Prescon Group opted for Legrand switches for Prescon Midtown Bay. Electric cables aren’t seen – but in their case, the emphasis is on reliability. As these may be needed in large quantities, the delivery schedule must also be considered. Godrej Properties opts for Polycab, KEI or equivalent cables, Tridhaatu Aranya features Polycab or Schneider cables, Prescon Midtown Bay also features Polycab cables while Siddha Seabrook has cables from Polycab, Gold Medal, Gloster, Mescab or RR Cables. “The evaluation of gensets must go beyond brand to include compatibility with the latest pollution control board norms, fuel consumption, dimensions, warranty and after-sales services,” says Kukreja. Whereas Tridhaatu has opted for Kirloskar gensets and substations for Tridhaatu Aranya, the Siddha Group has opted for Kirloskar, Sterling Generators or Moteurs Boudouin gensets for Siddha Seabrook. Godrej Properties prefers Sterling, Cummins, MTU or equivalent gensets. Façade lighting A few critical factors for the success of façade lighting in tall buildings are having IP65 to 67-rated fixtures, integrated/housed in the structure to increase their life and protect them from harsh weather conditions, says Ekta Sanghvi, Founder, Principal Designer and Director, Lighting Concepts. “Only when the lighting cables, connectors and fixtures are installed correctly will the system stay alive, a recipe for long-term success. Else, no matter how good the components are, the lighting will not function properly and the replacement maintenance and re-installation cost will increase.” Sanghvi points out that correct installation entails advance planning. “Plan the façade lighting when you’re at the design board level. Façade lighting as an afterthought attracts surface-mounted fixtures open to harsh weather, which isn’t advisable,” she cautions. “Advance planning means that even if you need to delay the purchase of the fixtures for budgetary reasons, at least you will have allocated spaces for the installation of the components.” “Façade lighting components like drivers and controllers are better installed in accessible locations like the ducts and lift cores,” Sanghvi continues. “Being an electronic component, the drivers may require maintenance and are best installed in distribution boxes. A separate UPS/stabiliser for the lighting fixtures and drivers is advisable where the electricity supply is not stable, especially in Tier 2 and Tier 3 cities.” The Qlite façade lighting system is Tridhaatu Realty’s choice for Tridhaatu Aranya. HVAC options An HVAC system for a tall building project should, at the minimum, be selected after considering factors such as the building usage, size, budget, energy-efficiency goals and maintenance requirements, says Suhas D Randive, MEP Consultant, Design Engineers. “Additionally, this choice may be influenced by local climate conditions and regulations, and the desire to integrate smart controls and monitoring systems to enhance the performance of the chosen HVAC system.” Besides brand and cost, evaluate the power consumption, space requirement, warranty and after-sales service of an HVAC, advises Kukreja, Typically, chilled water systems are chosen for commercial tall buildings for their design flexibility and scalability, continues Randive. “While these may be based on air-cooled or water-cooled chillers, the water-cooled chiller based systems can especially be highly energy-efficient, but require careful design and maintenance. The higher cost of these HVAC systems can be offset by their long-term operational efficiency.” “Variable refrigerant flow systems suit both residential and commercial tall buildings,” adds Randive. “Their wide variety of indoor units allow for zoning and individual control, providing personalised comfort. When integrated with AHUs, centralised air distribution becomes possible. Through variable capacity control, they offer high energy-efficiency. Also, their ductwork needs less space compared to traditional systems.” Randive notes that direct expansion systems commonly used in residential tall buildings, where zoning and individual control are not critical, are much simpler to install and maintain, and generally more cost-effective for smaller-scale projects or individual unit installations. Tridhaatu Aranya features Mitsubishi or Toshiba VRV systems while Siddha Seabrook has Krugar systems and Prescon Midtown Bay has Daikin systems. Vertical movement After the structure, the most critical prerequisite for a viable multistorey building is an adequate elevator system, selected through a detailed design process, says Tak Mathews, Director, Tak Consulting, and Convenor, Elevator & Escalators Codes, National Building Codes of India. Quoting the late lift industry leader Dr Gina Barney, Mathews points out that the planning and selection of transportation equipment necessitates the calculation results to be tempered with a great deal of working experience drawn from existing buildings to ensure satisfactory design results. But municipal building approval requirements, including norms laid out by the High-Rise Committee, do not mandate elevator adequacy as a prerequisite, adds Mathews. “Also, in drafting standards, the underlying pressure is to meet market demands and sometimes diluted European norms rather than the rigid safety rules required for the specific Indian situation. Consequently, the general approach to selecting an elevator is to cut costs from hiring a design consultant (if hired at all) to procurement (both numbers and quality) to maintenance (leading to accidents). So much so that despite steep rising input costs, the price of elevators has been reducing, certainly not because of technological innovations but because the elevator industry has commoditised this very specialised field and is engaged in fighting for an unrealistic market share.” Coming to the preferred brands of developers, Godrej Properties prefers elevators from TKE, Schindler or equivalent brands. Tridhaatu Aranya also features Kone elevators. Prescon Midtown Bay has elevators from Schindler India while the Siddha Group has opted for Johnson, TK Elevator, Hitachi, Otis or Toshiba for Siddha Seabrook. Surveillance systems Today, tall buildings are not just residential multistorey structures but have evolved into integrated multizone, multiactivity complexes, with basements and podiums housing parking, services such as pump rooms, sewage treatment plants, fire command centres, and amenities such as a gym, pool, gaming area, party lawns and banquet rooms, observes Nimish Shah, Director and Principal Consultant, Meptek Consultant. “Such complexes have multiple entry points, separate elevators for occupants and service staff, multiple staircases and refuge floors necessitating extra detail to security and surveillance. It is a common practice now to cover all the public areas, lobbies, parking areas, staircases, entry-exit points and elevators with surveillance cameras with night vision capabilities.” Based on the location being monitored, the choice of camera will vary between pan, tilt and zoom (PTZ) cameras, infrared night-vision cameras, dome cameras, bullet cameras, C-mounted cameras, IP systems, wireless cameras, day and night cameras, and HD cameras, he explains. “These systems are integrated with the overall security software of the building, which stores the footage for three months.” A visitor management system is also a tall building must-have, adds Shah. “Most new towers have restricted entry points controlled by turnstiles. Visitors are given access only after receiving confirmation codes from the occupants. Biometric thumb or face readers are gaining popularity to let in/out registered occupants and staff, as these eliminate the need for access cards.” Shah cites guard monitoring systems to track security guards in real time as another important system being deployed. The location and route of security guards are monitored using geo locations, Bluetooth low-energy beacons and RFID tags. Their scheduling and patrol route assignments are automated. SOS alarms allow the guard to be alerted during panic situations. Godrej surveillance systems secure Tridhaatu Aranya while Hikvision, CP Plus and Godrej CCTV systems secure Siddha Seabrook. Paint trends Every developer looks for durability and finish in paints for tall buildings, says Vipin Gupta, Founder, Home Glazer. “Tall building exteriors are extremely challenging and expensive to paint; the job demands many safety precautions and a skilled team. Besides, occupants dislike the disturbance to their lives. So, developers prioritise long-lasting paints with waterproof qualities. Texture-finish options are highly desirable as these last longer than flat-finish paints although they cost about double.” “An overseas brand like SKK has made inroads in the market for ensuring durability and a high-end finish for tall building exteriors,” he continues. “Some local manufacturers offering quality paints, such as Acro and Asian Paints, are also being used by developers with the ability to test the various options for their chemical composition. Oikos is a textured finish option for interiors.” Asian Paints is Tridhaatu Realty’s preferred pain brand for Tridhaatu Aranya while Asian paints, Berger Paints and Nerolac Paints are the Siddha Group’s options for Siddha Seabrook. Prescon Midtown Bay features Asian Paints. Asian Paints, Berger and their equivalents are Godrej Properties’ preferred paint brands. Facility management Safety and security are critical considerations in the management of tall buildings. “The complex infrastructure of tall buildings makes robust safety systems, exit routes and occupant safety critical while highly evolved surveillance systems, access control systems and emergency protocols can ensure security,” says Charu Thapar, Executive Director, Property & Asset Management, Asia Pacific, Head of Strategy, Platform & Emerging Markets, India, Indonesia, Thailand, Vietnam, and Philippines, JLL. “Vehicular traffic and vertical movement are some other critical areas.” “Smart Energy Management systems can help reduce the operational costs and environmental impact of tall buildings; hence, tech-enabled systems such as sensors, smart lighting, smart air-conditioning systems and integrated building management systems are vital,” she continues. “Flawless and regular maintenance planning is crucial to ensure the lifespan of building components and, here, IoT, predictive maintenance and technology-aided systems are essential to manage such complex structures. Given the large volumes of waste generated, waste disposable, segregation and recycling systems and programmes are essential.” “Technology can underpin high quality management, monitoring and delivery; this can include BIM, smart building technology and computer-aided facility management with an overlay of AI,” adds Thapar. “These technologies can additionally deliver tenant/occupant complaint management and amenity booking for facilities such as gyms, swimming pools and other community spaces. Communication to occupants becomes easier on regulatory requirements, community events, food and beverage offerings, coworking spaces in offices and meeting room management.” The Siddha Group has onboarded JLL for Siddha Seabrook’s facility management. With so much going into a tall building, it’s good to know the options are manifold. - Charu Bahri