While Mumbai has been the front runner in high rise buildings with over 100 tall buildings constructed, other cities are slowly awakening to this new reality.
By R Shobha
With surge in land prices and short supply in urban areas, many developers are developing high rises in Central Business Districts (CBDs) and residential areas across the nation. However, these buildings have unique challenges both at building and city level. At the building level, the challenges are related to fire protection, such as longer egress times and distance, evacuation strategies, fire department accessibility, smoke movement and fire control. However, these challenges can be addressed by designing refuge areas in the building, adequate staircases and other egress mechanisms, smoke detection, early warning systems and firefighting systems. In addition, structural systems should be designed to withstand earthquake and wind pressure. Along with constructing safe buildings, it is equally important that the civic authorities should also work in tandem to ensure emergency preparedness at neighborhood and city levels. This implies that there should be adequate number of fire tenders and fire officials should be trained to combat emergency situations.
In the wake of a recent fire incident that engulfed a residential tower in London and raised the issue of how building norms are being flouted by developers to build high rises at lower costs and quick turnaround time, the National Building Code of India (NBC) has recognised the need for regulation and laid down provisions for construction of tall buildings, including fire safety, high speed transportation (elevators) systems and earthquake resistance. Additionally, NOC is needed for construction of buildings above 60 metres from recognised institutions. Fire safety clearance is also required from the Institute of Fire Engineers, Nagpur. The NBC has laid down several guidelines and provisions to prevent fire and ensure safety measures for occupants living in high rises. Some of the salient features include:
1) Provisions for fire and safety in modern complex buildings, like high rises, glazed buildings, atria, commercial kitchen and car parking facilities.
2) Updated structural design provisions for wind and seismic loads, imposed load due to helipad, and blast loads for safe design and construction of buildings, with focus on ductile detailing. IS 1893–2002, IS 4928–1993 include regulations related to earthquake-resistant structures. Based on the load factors, buildings should be designed as per NBC, IS 456.
3) Embracing latest research and development inputs and provisions on concrete, steel and masonry buildings with a view to ensure disaster resilient buildings.
The model bye laws of NBC 2016 regulates construction of high rise buildings which now have been relaxed. As the height restriction on construction of high-rise buildings have been regulated in Delhi and NCR, many developers as well as Haryana Urban Development Authority (HUDA) have planned 150-200 meters high skyscrapers. Similarly, other metros, as well authorities have recognised the need for high rises to cater to burgeoning population and shortage of land. While Mumbai has been the front runner in high rise buildings with over 100 tall buildings constructed, other cities are slowly awakening to this new reality.
On the contrary to popular belief that India lacks skilled workforce and technology to build high rises, the trend of vertical development is catching up fast across the country, especially in metros and suburbs. Availability of modern construction technologies and equipments have made it possible to develop safer high rise buildings. A case in point – Mumbai is the only city to boast of numerous 150 meters plus high- constructed buildings, as well as 200 meters plus buildings with globally accepted standards of construction. In addition, these buildings are largely residential projects.
Prior to designing and marketing their latest projects, developers should consult established design consultants and rely on their design and drawings for construction of such high rises as per statutory systems and construction practices. Though technical knowledge is pivotal for construction of high rise buildings, but effective implementation of norms, regulations, codes is also critical. Adoption of project management techniques in design and construction management of high rises therefore becomes imperative.
On the other hand, buyers should ensure that developers should have statutory clearances in place and building plans should include adequate means of evacuation/ egress, smoke and fire detection systems, firefighting systems, refuge areas along with a structure for managing emergencies. Good engineering practices coupled with stringent adherence to codal requirements and implementation of best practices during construction can ensure that high-rise buildings are adept with highest level of quality and safety.
(The author is National Director, Project Management, Colliers International India)