GS Paper III

News Excerpt:

India's booming construction industry offers economic growth and better living standards but also raises environmental concerns. Sustainable buildings are now needed to address those environmental impacts and meet the demand for energy-efficient structures.

Need of sustainable building material:

• India is witnessing an unprecedented construction boom, with over 3,00,000 housing units erected annually. 
• The building sector is a major energy consumer, accounting for over 33% of India’s electricity usage, contributing to environmental degradation and climate change.
• The India Cooling Action Plan forecasts an eight-fold increase in cooling demand between 2017 and 2037, emphasizing the need for thermal comfort while reducing active cooling demand.
• Energy inefficiency in residential buildings demands attention, given India's rising energy and cooling demand due to economic growth, urbanization, heat islands, and climate change.
• Current construction practices often prioritize fast-paced, energy-intensive methods with active cooling strategies, leading to compromises in thermal comfort.

Challenges posed by current building material:

Popular building materials in warmer-climate Indian cities include Autoclaved Aerated Concrete (AAC) blocks, red bricks, fly ash, and monolithic concrete (Mivan).

• Red bricks exhibit moderate embodied energy, contributing to resource depletion, emissions, and waste.
• Red bricks were found to require the longest construction time for a 100 sq. ft room, whereas Mivan construction required the least.
• AAC blocks, although having lower embodied energy, still contribute to emissions and waste.
• Monolithic concrete, despite its quick construction time, presents the highest embodied energy, significant environmental impact, and sustainability challenges.
• Over 60% of buildings in the design and construction phases choose monolithic concrete, particularly for high-rise buildings and skyscrapers due to its speed, strength, quality, and scalability.
• The construction industry’s preference for Mivan as a prime building material raises sustainability concerns, including high embodied carbon and thermal discomfort. 

Initiatives taken:

• Initiatives like the Eco-Niwas Samhita (ENS) and Residential Energy Conservation Building Code are positive steps in the right direction.
• The ENS introduces the Residential Envelope Transmittance Value (RETV) to measure heat transfer through a building's envelope.
• Lower RETV values lead to cooler indoor environments and decreased energy usage. 
• Maintaining an RETV of 15W/m2 or lower is recommended for optimal efficiency, occupant comfort, and reduced utility expenses.

Way forward:

• AAC blocks offer a better balance between embodied energy and construction time than red bricks and monolithic concrete.
• During RETV evaluation, AAC blocks consistently had the lowest RETV across all climatic conditions, indicating their potential as a thermally efficient material.
• Collaborating with sustainability experts across disciplines can help optimize building design strategies such as orientation, Window Wall Ratio (WWR), U-value (heat transfer rate), roofs and window assemblies, glazing performance, and active cooling systems. 
• This collaboration is crucial for unlocking the potential for a sustainable built environment.
• Sustainable construction requires innovation from building materials manufacturers to develop cost-effective, scalable, durable, fire-resistant solutions with superior thermal performance and climate resilience.
• Perceptions of high first costs as a barrier to the design and construction of climate-responsive buildings need to change. 

Conclusion:

The journey toward sustainable construction is challenging but essential for a greener future. By re-imagining construction design and practices, manufacturing innovative walling materials, and fostering a culture of sustainability, we can create resilient and energy-efficient structures that align with environmental goals and significantly improve the quality of life for the masses.