August 31, 2023

The design logic of decarbonization

Donnelly

Consider your good fortune! You live in a time of unprecedented opportunity. Individually and collectively, the actions we take over the next several decades to address global carbon emissions will almost certainly shape the course of human and environmental history well beyond our reckoning. Human civilization has never faced consequences of such significance.

The creativity and commitment with which engineers and architects have responded to this challenge is unequaled by any industry. Yet we want to continue to challenge ourselves to do more and do it faster. That is our purpose here.

Because the present moment calls for a decisive break from certain cultural norms, it is useful to consider historical examples where a similar need prevailed. Early practitioners of modern architecture understood their work in the context of an all-consuming modernity — a radical break from the past — employing new materials, industrial processes, and social programs.

We can and must embrace the example of our predecessors and approach our work as an instrument of change, in concert with a broader movement to decarbonize buildings, cities, industry, and transportation.

At Integrus, embracing the design logic of decarbonization means asking sometimes difficult questions about our own practices, and a willingness to transform that practice in the process. Here are some examples of how a deeper integration between our structural engineers and architects reduces the embodied carbon of our projects.

Photo by Lara Swimmer, courtesy of Integrus [enlarge]

Ceiling at Eastside Catholic High School, designed by Integrus: Integration of structure, material, and natural light.

Beam deflection criteria and carbon

When an architectural solution suggests long-span steel beams, cantilevers, or heavy materials such as masonry veneer supported by long-span beams, we know that the strict deflection criteria for steel beams will result in larger beams and more carbon. This is the moment when our engineers run quick calculations of the embodied carbon of different design solutions, seeking the lowest carbon solution that satisfies the architectural criteria.

On a recent canopy design for Tyee High School, this practice resulted in a savings of 26,000 kgC02e. That’s the equivalent of 29,000 pounds of coal, or the carbon sequestered by 34 acres of US forest in one year.

Don’t Penalize Your Lateral Systems

The placement or orientation of lateral systems can result in code penalties that require larger columns or larger foundations to resist overturning, both of which add carbon. Our engineers and architects keep carbon metrics in the mix of design variables, supporting low-carbon decision-making.

Keep it simple

In the design of educational facilities, the need to accommodate diverse programmatic and spatial requirements often favors layouts of columns that depart from a regular and repetitive grid spacing, increasing the number of columns, and adding carbon in the process. In this instance, engineers and architects work together to accommodate program requirements within a “carbon constrained” structural layout. These are often relatively small decisions, but small decisions add up.

Where’s the brick?

Brick is an essential material. It is beautiful, adaptable, and indispensable for conveying quality and gravitas. However, it is a relatively high embodied carbon material. As with other high-carbon materials, we exercise care in how and where we use it. The weight of brick can result in increased foundation sizes and increased load requirements in certain circumstances. We strive to use brick mindfully.

Transparency

This measure brings us back to the architecture of the early 20th century. In 1921, Mies van der Rohe’s entry for the Friedrichstrasse Skyscraper competition beautifully engaged with the technology and materials of the time, featuring exterior walls freed from their load-bearing function, transforming solidity into transparency. Conceived only a few years after the end of World War I, this seminal project presented a bold vision of the skyscraper as a new architectural typology for the modern metropolis.

Fast forward again to the 21st century. Mies’ fascination with glass has become our fixation. For contemporary buildings of all types, transparency appears to be the default enclosure. This is a problem because glass curtain walls are subject to significant thermal gain, and do not meet the growing need to prioritize reductions in operational and embodied carbon emissions. If we are going to embrace architecture as an instrument of change, shouldn’t we subject our love of transparency to the logic of decarbonization?

Shouldn’t our response to a warming planet start showing up in our building facades? While our architectural visions have changed very little over the last 100 years, annual global carbon emissions from burning fossil fuels have. When Mies submitted his design in 1921, emissions were less than five billion tons a year. Today, they are over 36.

Fortunately, there are many examples of buildings where transparency is used, not iconically, but in ways that celebrate the experience of light in balance with enclosures that speak to more than just transparency. From modern masters such as Louis Kahn, Alvaro Siza, and Le Corbusier, to contemporary architects like Grafton and Marlon Blackwell, there are alternative approaches to thoughtfully integrating light and views while limiting glazing. And, if we look a little harder, past the typical canon of western architecture, we see myriad examples of indigenous architectures from around the world that embrace an aesthetic of limited openings, local materials, and high climate-sensitivity, all while meaningfully expressing their place and culture.

The burden and opportunity of this moment demands something extraordinary from us. We know how to do this. We have historical precedents. Our predecessors engaged critically and beautifully with the engineering, scientific, and cultural context of their time. We inhabit an entirely different context. Shouldn’t our architecture inhabit that context too?

Patrick Donnelly is director of sustainable design at Integrus.

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