News You Can Use is a timely digest of webinars, events, recent news, research, resources, and discussion from across the building industry focused on driving the radical reduction of building construction and materials.
“Traditional Construction is Doomed to Disappear”: Interview With the Portuguese Office SUMMARY (ArchDaily)
For SUMMARY, a Portuguese architecture studio, the reasons for creating modular structures like this mixed-use building are largely financial. But modular/prefab is well positioned to reduce construction waste and improve options for building reuse.
Prefab doesn’t necessarily hinder creativity. Rather than the shape informing the construction system as with traditional architecture, the construction system informs the shape. SUMMARY hasn’t always found success with its prefab endeavors — some components were too large for practical transportation and handling, and there have been problems with scalability and replicability — but the firm is learning from its mistakes.
Potential benefits of prefab include but are not limited to material efficiency, improved quality control, embodied carbon reduction, reduction in impact from building operations due to tighter joint tolerances, better support of adaptation/reuse and recycling, improved indoor environmental quality, safer working conditions, less disruption to the surrounding community, and potential to help meet the need for affordable housing.
A study of prefabricated high-rises in Hong Kong found that substantial reductions in embodied energy can be achieved by using precast elements with reduced Portland cement content. A taphouse in Denmark was designed specifically with disassembly in mind. The rise in popularity of mass timber brings new potential for producing wall, floor, and roof panels offsite. We must build upon this body of knowledge to ensure the building industry is exhausting all effective decarbonization methods, as part of a multi-pronged response to the climate crisis.
What reuse or disassembly projects have you worked on, and what were the most notable challenges and successes?
CarbonCure was recently named one of two winners of the $20 million NRG COSIA Carbon XPRIZE. And for good reason! It’s a cost-effective way to reduce the global warming potential (GWP) of any concrete mix by about 5%. But if you’re starting with a mix with above average GWP, then it’s a stretch to call the new mix “low-carbon,” even if it has CarbonCure.
This is why we need more mix-specific EPDs so designers can use actual GWP values as a design metric. CarbonCure is not a stamp declaring any mix that uses it “low-carbon,” but it’s often used as such in lieu of actual GWP data. There are CarbonCure mixes with GWP far below and far above that of NRMCA regional average concrete mixes. Only readily available mix-specific EPDs in a database like EC3 that can solve this problem. Other effective GWP reduction strategies for concrete include
- Use Portland limestone cement (also known as GUL, or general use limestone) over regular Portland cement
- Be mindful of cure times rather than arbitrarily specifying strength at 28 days
- Move toward performance based requirements rather than specifying water/cement ratios or minimum cement content (perhaps even specify maximum cement content in lieu of EPDs)
- Supplementary cementitious material (SCM) replacement, though keep in mind that it’s cement content that matters. % replacement is just one way to achieve cement reduction.
- CarbonCure. A great next step would be for CarbonCure to encourage concrete suppliers using their product to produce mix-specific EPDs to show off their impact reductions and avoid greenwashing
(I’ll add to the list if anyone has other ideas in the comments!)
Buy Clean policies on local, state, and federal levels will help eliminate a frustrating catch-22 where concrete suppliers don’t want to spend money to produce EPDs because designers aren’t asking for them, but designers aren’t asking for them because concrete producers aren’t producing them. So take the first step and include EPDs in your specifications! Start the conversation. Bring up embodied carbon early and often, and make EPDs a part of that conversation.
The construction industry is responsible for between 33% and 40% of global resource consumption and a similarly high proportion of waste. Reducing the amount of waste requires reuse and recycling, part of a “circular economy.” This article offers a snapshot of circular construction efforts in Europe, motivated by an EU-wide circular economy action plan created in 2015 and updated in 2020. The European Commission will release a plan for sustainable built environment strategy later this year that will establish recycled content requirements and, potentially, revise material recovery targets.
Designers should be taking actions that include (1) using less material by refurbishing existing buildings whenever possible; (2) favoring non-virgin and renewable materials; (3) ensuring materials have a life beyond their initial purpose by designing for disassembly; and (4) selecting materials with high capacity for reuse or recycling like wood or steel.
One Click LCA has a building circularity tool that allows designers to measure and visualize the circularity of their design by tracking resource flow into and out of a project.
This analysis gives a representative (but not quite comprehensive) look into global steel production and its various decarbonization pathways. As it stands, substantial GHG reduction in steel production is only possible with substantial cost increases.
But there are important steps that can be taken immediately; this report explores hydrogen or biofuel replacement of fossil fuels, carbon capture and storage retrofitting of steel production, electrification and low-carbon electricity, and biomass substitution for coke as they apply to electric arc furnaces (EAFs), basic oxygen furnaces (BOFs), and direct reduced iron (DRI). BOFs currently dominate the global market, producing 71% of steel worldwide, but are inherently difficult to decarbonize substantially.
Speeding decarbonization will require investment in low-carbon infrastructure enablers, government incentives, green procurement policies, low-carbon production standards as regulatory drivers, replacement of high-impact facilities with low-impact alternatives, and development of international low-emission production standards.
With embodied carbon legislation on the rise, more design professionals will be looking for suppliers who can disclose the environmental impacts of their products. . EPDs allow providers to showcase their low-carbon materials and EPDs stand out in a crowded marketplace by demonstrating their commitment to sustainability. They help designers make data-driven decisions and receive credit from such rating programs as LEED, BREEAM, DGNB, and the Living Building Challenge. There’s a lot of value in staying ahead of the curve as the design industry shifts in this positive direction.
Powerful article about the use of ‘net-zero’ as a way of evading real action on climate change. I agree with the sentiment: net-zero sounds basically as good as zero, but it’s actually not nearly as ambitious and would not be enough to mitigate the climate crisis. Emission reduction before offsetting must be at the center of any effective climate initiative. There’s not enough room for everyone to offset their carbon, so it’s important to take ‘net zero’ with a grain of salt. Even with ambitious, far-away goals like 40% embodied carbon reduction by 2030 and zero carbon by 2050, we need swift, dramatic action immediately. What GHG pollution is still taking place, even on the most ‘sustainable’ projects? Zero is much more demanding than net-zero and we should treat these phrases accordingly. – Martin Torres.
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