The drive to sustainability is racing ahead. A decade ago, zero-emission vehicles were just outlines of an emerging horizon. Today, they are no longer ideas. Moreover, they are autonomous. Range anxiety is now a novel feature of our daily existence. And as humanity races ahead we are already seeing many modifications to new and existing projects. The construction industry is no exception. Activities of the built environment are experiencing multiple disruptions as the world addresses the challenges of the green transition head-on.
The complete life cycle of residential and commercial buildings from design to demolition constitutes a highly fragmented ecosystem. At every stage along the product life cycle, stakeholders in this highly complex ecosystem can capture opportunities to combat environmental risks. To nurture environmental resilience at every level of the ecosystem, participants can begin to consider risk-sharing schemes like performance-based energy-reduction contracts, green mortgages, and blockchain-based platforms designed to allocate savings from energy-efficiency investments.
Every stakeholder in the ecosystem can contribute to this transformation. Depending on the asset type, stakeholders can have an impact on emissions at multiple stages of the product life cycle. Developers can influence design and planning that take into account issues ranging from waste sources to green-design solutions using building-information modelling, wastewater management, air quality control, IoT-based energy management, and the impact of the structure on biodiversity.
Thoughtfulness in shape, form and placement of the building’s components to harness natural daylight avoids daylight robbery and improves energy efficiency for cooling. This gives consideration to the climate and sun orientation relative to the building site. Natural ventilation which allows indoor air to circulate continuously. Carpets which easily trap dust particles between vacuuming. Easy-care plant species that function as natural air filters. Smart windows that can control the room temperature using blinds and shades to control the amount of sunlight that filters into the interior. Solar panels and wind turbines which produce some of the energy needs of the structure.
Paint must not release substances harmful to the health of the occupants. Scientists at Purdue University in Indiana have added calcium carbonate to a paint mixture. They found that using high concentrations of calcium carbonate, with different particle sizes, enabled the new paint to reflect a broad spectrum of wavelengths. The result is a new product with very high reflectance. This paint may have a broad range of applications especially in data centres, as these structures require large amounts of continuous cooling. Contractors on the other hand can have an impact on structures by selecting new materials. Selecting low volatile organic compounds (VOC) building products may be a top priority. The use of reflective surfaces and white paints in interior spaces helps to increase the amount of light without adding more lamps.
Residential and commercial real estate are among the major contributors to greenhouse gas emissions. Fuel combustion for cooking emits carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Wastewater treatment plants emit CH4 and N2O. Organic waste in landfills emits CH4. Refrigeration and air conditioning systems discharge hydrofluorocarbons (HFCs) when leaking or during routine service. And the burning of fossil fuels at power plants to generate electricity for commercial buildings, factories and residential building contribute to indirect emissions.
Achieving zero emissions from the existing built environment requires a thoughtful detailing of building intervention points in the lifespan of existing commercial and residential real estate. These pain points open up possibilities to align and integrate building upgrades with existing capital improvement and renovation cycles. This may require: 1) renovating existing buildings using recycled materials, and upgrading for deconstruction; and 2) specifying the use of new low to zero carbon building materials alongside organic materials like natural stone and wood. Builders may have to extract some materials in existing structures in an environmentally responsible way to lower the negative impact on the ecosystem. Since about eighty per cent of the anticipated building stock for 2050 exists already, there is a huge opportunity to retrofit existing assets.
This requires an audit focusing on the production, processing, transportation, and proper disposal of each material prior to extraction. Some pressed-wood products may have been treated with harmful chemicals. Once extracted, all materials must be tested for toxins and other contaminants to determine how they will be contained, transported, and stored in locations or facilities approved by an environmental management authority, and not simply sent to a nearby landfill. From extraction to disposal, the chain of custody of the materials must be managed by authorized agents of the state, and breaches can result in penalties and fines.
Unlike operational carbon emissions, which can be reduced over time with building energy upgrades, embodied carbon emissions are locked in place as soon as a building is built. To achieve zero emissions by 2040 it is important to get a handle on embodied carbon. Concrete, steel, and aluminium are responsible for about 23% of total global emissions. Apportioning GHG emissions across the construction ecosystem is not straightforward. However, the Covid-19 portal has presented an incredible opportunity for embodied carbon reduction through building codes, design specifications, and materials selection. Change is arriving fast. And the pandemic accelerant has fast-tracked the drive to sustainability.
