Even as the construction industry is booming, can the country’s commitment to reduce carbon emissions be met? Green building advocates say a building should be operational and address the concerns of embodied carbon.
Building technologist Mili Majumdar, a votary for sustainable buildings, explains that embodied carbon is the amount of carbon emitted during the life of building materials. It includes concrete, steel and insulation materials. The carbon dioxide released during extraction, manufacturing, transport, construction and disposal of all construction materials contributes to embodied carbon emission.
Mili Majumdar receiving the Distinguished Alumnus Award at Indian Institute of Technology Madras. | Photo Credit: Special arrangement
Majumdar was involved in developing methods to rate buildings based on their ability to reduce carbon emission. She is credited with developing GRIHA (green rating for integrated habitat assessment) during her tenure at The Energy Resource Institute, a non-government organisation.
Can residential buildings be green buildings? Yes, says Majumdar. India has developed several codes such as the National Building Code and the Energy Efficiency Code. Buildings that comply with the codes would lead to a sustainable environment, she points out. The problem is that “developers are introducing newer methods as they are faster, quicker and easier, but they are not necessarily energy efficient.”
Majumdar was recently in Chennai to receive the distinguished alumni award presented by her alma mater, the Indian Institute of Technology Madras, where she completed her post-graduation in civil engineering.
She graduated in architecture from Jadhavpur University, Kolkata. She is currently the managing director, Green Building Council India, and senior vice president, US Green Building Council.
She cites the United Nations Environment Programme report that says 37% of global emissions are from building materials such as cement, steel and aluminium. One of the methods is shifting to regenerative materials. The current methods of construction would require further layers of insulation and add greenhouse gas emissions.
Builders must comply with the Bureau of Energy Efficiency codes for the envelope of residential and commercial constructions, she explains. The envelope of a residential building includes the foundation that supports the structure; the exterior walls; the roof; windows and doors. A sustainable building is one which is insulated against the vagaries of weather. “An effective envelope provides physical protection from climate, indoor air quality, durability and energy efficiency,” she adds.
“You can have a zero-energy building by lowering your consumption to minimum and offset with renewable energy. You can produce equal to what you generate,” says Majumdar. “This can be done by introducing energy efficiency measures; reducing energy demand; and moving towards 100% use of renewable energy. Green is a combination of materials, indoor environmental policy, waste management, embodied carbon, urban heat island, water... there are so many things that you look at holistically,” she adds.
Construction in cities has moved far from the conventional methods of cross-ventilation. “In a village, ventilation to lower energy use would be correct. But think of a place like Delhi. When the outdoor pollution is high, what will happen to the indoor air quality?” she asks.
She notes that despite specific and elaborate codes for sustainable buildings, the compliance is not full.
Green buildings do not cost more than conventional structures, she points out. By using lightweight materials (such as alloys of metals, polymers), reusing demolished material from construction sites, and complying with green building regulations, builders can reduce cost.
“We have energy conservation code and environment clearance requirement. A mandate alone is not good enough if we do not have implementation. For that you need a lot of awareness and capacity building also so that people can implement it,” says Majumdar.
