As the urgency of treading more lightly on the earth takes centre stage this month, we take a look at new green construction best practices that are leading North America to a cleaner – and greener – building industry.
As we grow more aware of our impact on the earth, reducing carbon emissions is inevitably at the top of our to-do lists. Construction and its related industries have long been considered some of the biggest contributors to greenhouse gas emissions (GHG) on the planet today. But with nearly 20 percent of Canada’s total GHGs being ascribed to buildings, simply cutting carbon in one area can mean doubling GHGs in another.
Therefore, becoming acutely aware of the blind spots in our existing attempts at cutting carbon is of the essence if the industry is to make a lasting impact on reducing its carbon footprint in the long term.
According to a new white paper that deals with low-rise residential building, published by Builders for Climate Action, there are practical building solutions to these challenges that can help the construction industry get to net-zero construction in about 30 years.
These solutions affect each phase of the building process, from mining, fabricating and moving materials, to the energy efficiency of finished buildings, and even the emissions created when cooling or heating.
The paper indicates a number of main areas that need to be addressed to reduce carbon emissions when planning a new building or development. These include upfront embodied carbon emissions (UECs). This is carbon emitted during the process of obtaining building materials – from their origin to delivery at the job site. On a global scale, UECs are estimated to sit at just over 10 percent of the total global source of GHGs.
Then, there are the two types of operational emissions. First is energy-use intensity, which refers to the complete energy needs of buildings. Second, and lastly, fuel source emissions are concerned with the fuel consumed for running electric appliances, temperature control, etc. According to reports, these make up nearly 30 percent of the world’s total GHG production.
In September 2019, the World Green Building Council (WorldGBC) announced its strategy for reducing UECs by 40 percent by 2030. It also proposed a robust plan for achieving 100 percent net-zero carbon buildings by 2050.
According to research by the Intergovernmental Panel on Climate Change (IPCC), taking charge of embodied carbon emissions alongside all other GHGs is crucial to keeping the global temperature increase under 2°C. Thus, the main focus is on finding and developing climate-friendly building materials with a reduced global warming potential (GWP), in contrast to high-carbon concrete.
Going au naturel
Aside from moving to a low-rise building solution in order to curb emissions, Builders for Climate Action has also published several significant solutions based on organic materials. The group advocates a return to natural building materials like rice hulls, sustainable timber, cork, hempcrete, hemp fiber, and bamboo.
The most unusual of its suggestions is mycelium, a porous fiber that forms the base organism of various types of fungus, like oyster and shiitake mushrooms. Mycelium is currently being tested for its performance in bricks and insulation.
The greatest challenge in developing modern building materials based on compostable organic matter is ensuring sturdy resistance in the face of wind, rain, sunshine and even fire. And the main argument driving Builders for Climate Action’s advocacy of these revolutionary materials is that natural materials do not emit carbon, but instead store a larger amount of CO2 than is created in obtaining the material. So major carbon savings can be made by using such materials, making the net-zero goal of the construction industry not only possible but also achievable in only a few decades, if the performance of these materials against the other criteria is acceptable.
Tackling operational emissions
In its discussion on reducing energy-use intensity and fuel source emissions, the Builders for Climate Action’s white paper cites a study performed by seasoned industry experts, Jacob Deva Racusin and Andrew M. Shapiro. They applied a dynamic, hourly simulation energy-modelling program based on a protocol created by the United States Department of Energy to study data obtained from climate research in Toronto, Ontario.
Racusin and Shapiro set out to establish the contrast in between natural gas and electricity used in a net-zero, single-family home. The outcome indicated that such homes heated only with electricity had lower carbon emissions compared to similar homes heated with natural gas. The former scored close to a 70 percent reduction in operational carbon emissions compared to just under 50 percent for the latter.
Naturally, the exceptional airtightness and insulation of these buildings played a significant role in controlling temperatures, as it would in rendering any building net-zero ready.
To render buildings carbon smart it’s best to study how they perform in the face of weather and the elements, as this ultimately decides their subsequent energy consumption. To understand the often complex process of becoming carbon compliant, help is at hand. Energy experts like Building Knowledge, Canada, Inc., set out to make new ‘green’ building codes more user-friendly, especially for those in the residential construction field.
Companies like these offer home inspections, testing, enclosure reviews, and assistance for builders who need to comply with standards such as those proposed by ENERGY STAR® and other environment-related-standards bodies.
They also lend assistance with achieving the energy-efficient net-zero GHG levels that will eventually be demanded of energy codes, as discussed at a groundbreaking meeting of the – wait for it – National Building Code of Canada Standing Committee on Energy Efficiency in Houses and Buildings (SCEE) in 2019.
The new model codes resulting from these talks are to be presented this year, after which they will subsumed into a body of law.
Progress, in stages
This code will help communities become part of a ‘low carbon economy,’ and also endeavours to move the construction industry forward over the next 10 years in preparation for a ‘Net-Zero Energy Ready’ plan, to be introduced by 2030.
The latest British Columbian code, called BC Step Code, is a tiered affair that will enable builders to meet the regulations and improve in stages, setting defined goals for the future with the clear intention of helping builders prepare for the code improvements ahead.
Some suggestions made by Builders for Climate Action hone in on using clean energy. For instance, it recommends that builders refrain from providing fossil fuel options for heating and insist on buying clean electricity from third-party vendors when available electricity is not carbon smart. The group also calls for policymakers to adapt their metrics in a bid to accommodate the urgency of the CO2 emissions issue.
Builders for Climate Action suggests that this should be done by moving on from the current energy-efficiency efforts to “Carbon Use Intensity” codes, testing all buildings for air-tightness and similar. It is exactly here where the important role of building scientists comes into focus.
As the industry moves ahead to meet this new era of curbing climate change by implementing positive changes, it has the opportunity to take a great step forward and ultimately render its product environmentally air-tight – for the good of us all and our environment.