Cutting carbon: three design and development experts discuss decarbonizing specifications

Earlier this year, KPMB Lab sustainability analyst Shahrzad Soudian moderated a Carbon Leadership Forum panel on translating decarbonization ambitions into real-world project specifications. To continue the conversation, we recently re-convened the panelists—Kael Opie, principal at KPMB Architects; Juste Fanou, founder of sustainable material database Bibliotech Inc.; and Vincent Davenport, director of Building & Materials Sciences at EllisDon—to discuss why decarbonizing the built environment starts with making better choices on paper.

What are the biggest barriers you face integrating low global warming potential (GWP) products into construction projects?

Kael Opie (KO): Integrated and consistent embodied carbon strategies are still emerging, and this means that carbon accounting is often done too late — if at all — and long after the window of opportunity has closed. It’s important that embodied carbon is treated as a core project metric, just like cost, energy efficiency, schedule, quality, and durability. All these factors are discussed early and often among entire project teams and balanced against one another. It’s time that we, as an industry, did the same with embodied carbon.

Juste Fanou (JF): Complicating things further is the fact that the industry lacks clear baselines for defining a “low GWP” product. Currently, most efforts seem to be focused on gathering data, such as product- and plant-specific EPDs (Environmental Product Declarations). We still need to define what exactly “low GWP” means.

From your perspective, do any project delivery methods allow for more effective tracking of greenhouse gas (GHG) emissions than others?

JF: As I see it, no single delivery method guarantees better GHG tracking. Success largely depends on education and early stakeholder buy-in. Construction Management and Design-Build can allow for earlier integration of emissions tracking, but traditional Design-Bid-Build methods can also be effective if requirements are clearly documented and communicated early.

Vincent Davenport (VD): Having a delivery model that allows for crosspollination and early-stage collaboration between designers, suppliers, and trades is critical. Embodied carbon needs to be part of the shared design process — not an afterthought managed by a single stakeholder. When carbon decisions are made in isolation, they risk conflicting with other important project requirements and being sacrificed in the process. KO: I agree. Any delivery method that encourages open and collaborative dialogue among all parties is a step in the right direction. Delivery strategies like Integrated Project Delivery (IPD) with an invested CM team or Progressive Design-Build can support this.

Procurement rules and competitive bidding processes often significantly impact material selections. How do industry- or client-driven rules impede or promote the use of low carbon products?

JF: Public procurement often follows an unspoken “three or equal” rule [requiring three equivalent product or material options be specified]. This can disadvantage manufacturers that offer lower embodied carbon or unique production methods. To address this, the industry should shift from highly prescriptive specifications, which often look like shopping lists for contractors, to performance-based specifications. Such an approach could encourage market-driven innovation.

VD: It’s important to have a clear direction from the client, combined with flexibility. Flexibility is required because embodied carbon is still a new idea. The path to achieving lower carbon might change or morph as you work through a project’s design. Not all products have Environmental Product Declarations (EPDs), and not all trades and designers are fluent in the topic. As a result, not all carbon reductions are equal in the effort that it takes to achieve them, the cost per kilogram, and their downstream impacts.

KO: While client leadership certainly sets the tone, it’s equally important that design teams engage and align early on specification strategy.

Like Juste, I agree with prioritizing performance-based specs. While they may sometimes lead to less predictable tender outcomes when not carefully managed, they reward sustainable practices and drive the industry forward. From my experience, clients with strict procurement rules can sometimes resist performance-based specs due to a lack of familiarity, so early and open conversations with the team are crucial. Make it a shared priority, and you might be surprised by what you can achieve.

To learn more about decarbonizing, contact KPMB Lab.