Analyzing Strategies For Decarbonizing Lab Structures

Is mass timber the best choice to reduce embodied carbon in labs? Can precast options handle the requirements of scientific work? Is a steel-frame building able to meet the lab vibration requirements? An analysis of laboratory structure strategies provides owners with choices that fit their priorities.

At a time when life science and research companies are working to reduce their carbon footprint, building a new laboratory facility is an expensive, complicated, carbon-intensive project. Structures can account for 50% of a building’s embodied carbon, making the material and system choices key in any carbon strategy.

From mass timber to concrete and steel systems, facility owners have an array of options with varying carbon profiles. But any choice still needs to meet the unique requirements of a laboratory facility, as well as the owner’s construction timeline and material costs.

Looking to better understand the integration of decarbonization goals into lab structures, LPA Director of Laboratory Planning Isabel Mandujano and Structural Engineering Managing Director Harshda Prasad analyzed a spectrum of structural options for labs, including the potential embodied carbon impact. Mandujano and Prasad, who have worked together on several recent laboratory projects, presented their findings at the 2023 Lab Design Conference in San Diego and the I2SL (International Institute for Sustainable Laboratories) Conference in Anaheim, spotlighting the need to take a holistic approach to choosing a structural strategy.

“You get different answers when you start looking at the whole project, with embodied carbon included in the analysis,” Prasad says.

The research included the unique considerations and strategies that impact the selection and design of structural systems in laboratory facilities, from floor-to-floor height requirements to vibration criteria. They also looked to balance performance requirements with decarbonization goals and explore the potential impact of new concepts and technologies. Different systems were examined for a wide variety of factors, ranging from embodied carbon and construction time to the system’s ability to handle loading requirements and the potential for future programming shifts.

“We wanted to understand the value of each system and apply that to different conditions,” Prasad says.

The study included mass timber, the most intriguing option. But mass timber’s use is still limited by code in many jurisdictions, and it’s not always appropriate for the unique requirements of a lab building. As a result, mass timber was considered in combination with a concrete topping slab, which performed well for embodied and construction time but wasn’t as efficient for construction costs and vibration performance.

No one system checked all the boxes. Overall, a structural design using steel beams with concrete over a metal deck earned the top scores, including high marks for construction time, construction costs and flexibility. But it can be difficult to achieve a high-level vibration performance in a steel beam system. A precast concrete system using high amounts of supplementary cementitious materials (SCM) produced the next best overall score, with high marks for embodied carbon and construction time. But a precast system might limit design options in the building, as well as the ability to adapt to future changes.

“Looking at the results, you see the advantage of hybrid systems,” Mandujano says. “Mass timber may not be the answer for every lab structure, but it can still be part of a building with different functions.”

The results also highlight the importance of including structural engineers and construction teams from the start of the design process, marrying functionality and constructability. Ultimately, building owners can view the data through the lens of their own goals and budget, choosing the elements that are most relevant to their project.

“An integrated design approach can find creative solutions that reduce the impact of the building where it matters and still keep the performance in the places that need it,” Mandujano says. “Every owner needs to look at the full picture of the decision and figure out their priorities, and they will be different for every project.”

Laboratories Are Different

Structural systems for office and commercial spaces don’t necessarily work for labs, which have their own specific set of requirements. For example, laboratories are typically designed for an 11-foot-wide planning module compared to 10 feet for offices, which results in wider column spacing and larger structural bays. Labs also need more above-ceiling space for air circulation and exhaust systems, as well as thicker slabs to handle higher load demands and strict vibration standards, which raises floor-to-floor height standards. In addition, sensitive scientific equipment requires controlled structural vibration criteria ranging from 6,000 to 2,000 micro-inches per second, imperceptible beyond criteria for human comfort only. Fire rating separation to handle hazardous materials adds complexity to the structural design.

The Analysis

The goal was to develop a holistic picture of structural systems and apply it to real construction, including embodied carbon. The analysis looked at six structural strategies, including mass timber with a concrete slab, a traditional concrete slab, precast concrete and steel. The evaluation criteria centered on seven areas: embodied carbon content, construction time, construction costs, floor-to-floor heights, vibration performance, design/program flexibility and future changes. Inclusion of flexibility and the ability to adapt to changes reflects the importance of resilient, long-living buildings in reducing carbon emissions.

The Results

The analysis across categories illustrates the pros and cons of each system. A system using mass timber resulted in only moderate embodied carbon savings, since a concrete topping slab is still required to meet lab vibration requirements. Mass timber’s value in embodied carbon was also offset by lower scores for construction costs, floor-to-floor heights and vibration performance. The best overall rated system — steel beams with concrete over a metal deck — has been shown to reduce construction time and costs, while increasing the flexibility and resiliency of the facility. A precast concrete system using 100% supplementary cementitious materials (SCM), which dramatically reduce the carbon emissions associated with concrete, produced top scores for embodied carbon and construction time but scored lower for limiting the flexibility of current and future spaces.

LPA is a signatory of the SE2050 commitment, which seeks to eliminate embodied carbon in structural projects by 2050.