CRSA Sustainability Series: By considering the entire life cycle of a structure, material or system, our buildings become smarter tools in making a positive impact for our clients as well as the environment.
Carbon is a well-known and researched contributor to our current climate, health, and sustainability challenges. Fully understanding its impact, however, is complicated. It takes looking into the entire lifespan of a product (or building) – from start to finish – to truly comprehend carbon’s effect.
Take a typical white t-shirt, for example: A shopper might narrow their choice down to two options, one made of 100% traditional cotton and the other an eco-friendlier blend of cotton and recycled material. Despite a larger price tag, the shopper purchases the eco-friendly option – a small environmental victory with a simple purchase.
The truth of this sale, however, is much more layered. Possibly, the "eco-friendly" shirt’s sustainability ends at its marketing and material. Maybe this t-shirt’s lifespan started in a fossil-fueled textile plant on the other side of the world and shipped for days just to get on the rack. Conversely, the 100% cotton option may have been manufactured in a renewable-fueled textile plant much closer to home. In other words, not all materials, products, and services are created equal. The same is true in the architectural world, yet with larger consequences.
There are two fundamental parts of the carbon issue – operational carbon and embodied carbon.
Operational carbon is the carbon needed to sustain a building after completion. Renewable energy sources, products with higher thermal properties, and more efficient electrical and HVAC systems are all important solutions to operational carbon and have come a long way, yet they only address half of the problem.
Embodied carbon refers to the “greenhouse gas emissions that arise from the manufacturing, transportation, installation, maintenance, and disposal of building materials,” according to the Carbon Leadership Forum (CLF). This kind of carbon is often overlooked because it’s less apparent, but it’s projected that from now until 2050, more than half of all construction-related emissions will be in the form of embodied carbon.
Analyzing a building's entire life cycle is critical in calculating both its operational and embodied carbon impact. Life Cycle Assessment (also known as Life Cycle Analysis, LCA, Cradle-to-Grave Analysis, or Eco-Balance) is a tool to document and predict both. For architects, "[l]ife cycle assessment (LCA) is one of the best mechanisms for allowing architects and other building professionals to understand the energy use and other environmental impacts associated with all phases of a building’s life cycle: procurement, construction, operation, and decommissioning."
Below is a breakdown of the Life Cycle Assessment process and what we, as designers, can do to reduce both operational and embodied carbon at each phase.
It all starts in the “cradle” – with the extraction of raw materials from the earth. This can vary in form, from cutting down forests and vast mono-culture crops to deep pit mines and quarries. These processes impact water supplies, soil degradation, biodiversity loss, ecosystem functions, and produce extreme amounts of carbon emissions.
Improving carbon impacts in this phase can look like:
Gone are the days where a building is constructed primarily of materials sourced nearby – lumber may come from Austria, steel perhaps from China and glass from opposite ends of the United States. Shipping materials across the world is no small deal. Transportation influences the life cycle of a building at multiple stages, such as transporting a raw material to be refined, moving that material to be manufactured or assembled into a workable product, moving it to a site, and once the material is decommissioned, relocating it to a landfill or recycling plant.
As architects designing for environmental health, we must consider sourcing and look for alternatives that offer a comparable product, but at a much closer proximity. For example, CRSA's team was recently tasked with finding a stacking glass wall system for a project. Some of the most popular options come from Europe, meaning their carbon impact is much larger than something sourced in the United States. In addition to landing on an option closer to home, our team worked to have the glass sourced even closer and installed on site.
Improving carbon impacts in this phase can look like:
Manufacturing, refining, and assembling raw materials into useable items such as steel, glass, and lumber contributes to around 30% of all global CO2 emissions. The good news, however, is that many manufacturers, large and small, are making great strides to become more efficient and environmentally conscious. These important changes include:
As members of the AEC community, we are responsible for investigating these manufacturers. Cost and product quality are often the two driving factors in making these decisions, yet, when possible, one should consider the points above to make a more well-rounded and conscious decision.
Emissions from vehicles such as trucks, welding equipment, cranes and the energy needed to power construction all leave their mark, contributing about 10-20% to overall emissions. Waste in materials, energy, and byproducts of construction all factor in, as well as the direct impact construction has on surrounding natural ecosystems. The science and techniques behind these processes are in flux, becoming more sustainable year after year, including:
When designers prioritize these techniques, our impact becomes more powerful. Designers should consider how products are dealt with at end-of-life stages, how systems can be installed efficiently using a more standard process that is easy to repeat, or how the design might decrease construction time by eliminating time-leeches that are avoidable or not crucial to the product.
According to Architecture 2030, 27% of all annual carbon emissions is sourced from building operations. By 2040, two thirds of the global building stock will be made of buildings that exist today. In other words, the choices we make in today's design of new buildings and retrofitting existing ones will have a significant impact for years to come.
HVAC systems, glazing, insulation, etc. all determine the performance of a building, with older systems understandably creating more pollution. Architecture 2030 also notes, "[f]or full building sector decarbonization, every existing building will need to undergo energy upgrades involving a combination of improvements in the energy efficiency of building operations, a shift to electric or district heating systems powered by carbon-free renewable energy sources, and the generation and/or procurement of carbon-free renewable energy."
Steps that can be taken toward this goal include:
Perhaps one of the biggest flaws in design of today’s buildings is the inability to easily adapt them for new use. Often, little attention is paid to providing systems, materials, and spaces to ensure the building's existence for centuries to come. Instead, the focus is placed on current needs.
According to a 2018 report by the EPA, 600 million tons of construction and demolition debris was generated in the United States. To mitigate the harmful effects of demolition, we can work with our clients to approach design for longevity and adaptability. Maybe this means designing more flexible spaces that have easily adaptable interior spaces, or from the very beginning, thinking about how a building may be utilized in its community down the road after its original use has expired. Additionally, looking at materials that will hold up for decades, or are more timeless in their use and appearance.
Recycling construction and demolition materials can help the impact of demolition waste. In 2018, 455 million tons of debris was reused in some form, such as material for construction aggregate, whereas 145 million tons were sent to landfills. Other benefits of reducing the disposal of debris include:
Through Life Cycle Assessment, we unveil the hidden carbon costs of designing and constructing a building. As designers, we have immense influence on this impact. Our design decisions have a far-reaching effect on environmental health and climate goals that can alleviate environmental disaster. By considering the total life cycle of a structure, material or system, our buildings become smarter tools in making a positive impact for our clients, as well as the places we live, work, and play.