6.1.2.2. Techniques for Reduction of Green House Gas emissions

The construction industry has several activities which result in direct or indirect Greenhouse gas emissions. The buildings and construction sector were responsible for 36% of total energy consumption and 39% of carbon dioxide (CO2) emissions related to energy use and industrial processes. Out of these emissions, approximately 11% can be attributed to the manufacturing of building materials and products, including steel, cement, and glass, as per IEA (2018). Thus, the concept of embodied carbon captures the implied CO equivalent/GHG emission.

The construction industry contributes significantly to greenhouse gas emissions, primarily from energy consumption during building processes and the production of materials. Specifically, it accounts for a large percentage of the total energy consumed globally and emissions produced. The concept of 'embodied carbon' refers to the total amount of CO2 emissions associated with the production of building materials, from extraction to manufacturing. This measurement helps inform strategies to reduce emissions in construction projects.

Think of building materials like ingredients in a recipe. Just as certain ingredients contribute more to the overall flavor, materials like steel and cement contribute significantly to the pollution created during construction. Understanding their impact is similar to being mindful of how much sugar or salt we add to our food - it helps us balance the recipe for a better outcome for the planet.

Techniques recommended by AIA are;

• Limit carbon-intensive materials, like aluminium, plastics, and foam insulation, and use judiciously.
• Choose lower carbon alternatives, such as, wood structure instead of steel and concrete, or wood siding instead of vinyl, and review Environmental Product Declarations for selecting alternatives.
• Choose carbon sequestering materials, like wood, straw or hemp insulation and bring down the embodied carbon in a project.
• Reuse materials, like brick, metals, broken concrete, or wood, as salvaged materials typically have a much lower embodied carbon footprint than those newly manufactured.
• Use high-recycled content materials, particularly for metals as they are carbon-intensive but can be recycled, which brings down its embodied carbon value.
• Use fewer finish materials, such as, polished concrete slabs in place of tiled, carpet or vinyl finished flooring saves the embodied carbon.
• Minimize waste, as discussed above. Modularity and standard sizes for common materials like plywood, gypsum boards, wood framing, and pre-cut structural members can be factored in during design and wastage can be minimised.
• Maximize structural efficiency, as it is the highest contributor to the embodied carbon of the project, and using optimum value engineering wood framing methods, efficient structural sections, and slabs are all effective methods to maximize efficiency and minimize material use.
• Reuse buildings instead of constructing new ones, as renovation and reuse projects typically save between 50 and 75 percent of the embodied carbon emissions compared to constructing a new building.

The American Institute of Architects (AIA) recommends several key strategies to reduce greenhouse gas emissions during construction. These include using less carbon-heavy materials, opting for materials that capture and store carbon, reusing salvaged materials instead of new ones, and maximizing efficiency in structural design. By minimizing waste and choosing sustainable building alternatives, construction projects can significantly reduce their carbon footprint. Additionally, renovating existing structures is far less impactful than constructing new ones, making it a preferred option when possible.

Imagine you are planning a birthday party. Instead of buying all new decorations and supplies each time, you could reuse items from past parties or borrow from friends. This saves money and reduces waste, much like reusing building materials does in construction. In essence, using what's already available can lead to a party - or a building project - that is both sustainable and beautiful!

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