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How do you build a world-class greenhouse to achieve LEED v4 certification? For Purdue and Pepper, the answer was clear as glass.
We love partnering with our clients on complex jobs, says Calvin Young, Project Executive, High Performance and Sustainable Construction, Pepper Construction Group, Indiana.
The new LEED v4 Certified high-tech Lilly Life Science Ranges phenotyping greenhouse that Pepper completed with Purdue on the university‘s West Lafayette campus last fall is a true reflection of this drive. The 18,993 square-foot facility is the second largest greenhouse—and one of only six—in the world to achieve this environmental stewardship certification. It’s designed to expand leading-edge agricultural and life sciences research capabilities that distinguish the national recognition of the university’s College of Agriculture.
The greenhouse can simulate growing conditions in any season offering the ability to accurately control CO2 levels, humidification, temperature and light levels. Each of the nine compartments that comprise the facility are fitted with four-pipe under-bench air handlers for hot water heating and chilled water cooling of the space, as well as roof vents with insect screens. Specialized conveyors enable efficient transport of plants between the new space and the adjacent Ag Alumni Seed Controlled Environment Phenotyping Facility to boost research workflows and data collection.
Environmental stewardship is woven as deeply in sustainability efforts at Purdue as it is in Pepper’s operations. Spearheading the ambition for LEED certification at Purdue, Anthony Gillund, Director, Sustainable Operations, acknowledged that reaching this prestigious recognition meant considering sustainable operations early in the planning process and clearing unique hurdles.
Here are Purdue we are consistently pursuing a balance between sustainability, reliability and affordability,” he says. “Our university believes in confronting challenges with creativity and courage. That means, we look for good, innovative partners and explore which paths allows us to best achieve our goals.
Backed by nearly three decades of partnership with Pepper in building long-term value, he knew he could proceed with confidence. “Our collaboration with the Pepper team is defined by clear communication and tight coordination,” he says, adding, “The supplemental expertise the team brought to creating a baseline energy model for a typical greenhouse and educating specialty contractors on the requirements of a LEED project helped get this project across the certification finish line.”
Together, the team understood that dealing with a greenhouse in LEED v4 BD+C (Building Design and Construction) required an unconventional strategy. The rating system is designed for projects that are constructing new buildings or taking on major renovations of existing buildings, including HVAC improvements, envelope modifications and interior rehabilitation. Greenhouses use energy for specialized cultivation. With unique envelope requirements, these structures have no default baseline in standard ASHRAE tables used in LEED documentation for HVAC, energy efficiency and indoor air quality. High heating and ventilation loads, not to mention glass walls and a glass roof, amplified the challenge of achieving the certification.
To enhance sustainability and improve efficiency and maintain reliability, the team engaged the architect, engineer and a greenhouse consultant in collaborating on an integrated, ultra-efficient design.
“In addition to incorporating essentials like natural ventilation, state-of-the-art LED lights, automatic sunshades to block excessive sunlight and energy-efficient glazing for the glass that performed better than the code minimum,” says Calvin, “we tapped into more novel channels like Building Envelope Commissioning (BECx).”
This distinct systematic quality assurance step complemented the university’s MEP requirements and aligned with the LEED Enhanced Commissioning credit. It allowed the team to verify electrical, mechanical and plumbing systems, as well as weather and air barriers, through third-party testing and design reviews. The upshot: proven proper functionality of systems in meeting efficiency and performance standards for the short- and long-term.
This rating system is designed for projects that are constructing new buildings or taking on major renovations of existing buildings (including major HVAC improvements, significant building envelope modifications, and major interior rehabilitation). LEED BD+C: New Construction and Major Renovations is flexible and can be applied to a variety of building types and uses.
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The Lilly Life Science Ranges phenotyping greenhouse was awarded 40 points out of a potential 110.
To clear the space for construction, two existing greenhouse ranges had to be demolished in a space constrained on one side by a heavily traveled road and on the other three by an adjacent building. A lack of structural steel typical in other types of projects posed additional hurdles for another major LEED focus: material recycling. The team successfully cleared the constraints, achieving 26.5% in recycled content for all materials and surpassed the 75% waste diversion goal by recycling 95% of the construction waste by weight. Concrete was crushed to be used as aggregate and metals recycled, supporting a backbone of the circular economy.
Conservative and conscientious, the team leveraged available resources, tying into the adjacent building to reduce water usage. Water efficiency doesn’t have to be complicated,” says Calvin. “It does, however, directly impact several LEED categories. From our perspective, this is not just about meeting code with the right fixture, but finding effective, systemic ways to help the project hit sustainability goals.
Monthly meetings kept all stakeholders informed and on track together. Starting with the predesign phase, the project implemented an integrative process, which created an opportunity to identify ways to enhance building performance and environmental benefits. When collective input revealed that more should be done to meet LEED Solar Reflectance Index requirements, for example, the team added tinted concrete without negative impact to timeline or budget.
Connecting regularly with the Purdue sustainability team and greenhouse end-users also led to the addition of water-resistant flooring, which addressed certification requirements for low-emitting materials credits and the need for functional water management critical to the greenhouse ecosystem. Decision making incorporated knowledge about healthy materials and resources including the Pepper Healthy Materials library, a single-source database system of trusted up-to-date materials information organized around the Construction Specifications Institute’s 50 divisions.
“Pepper consistently demonstrated a strategically thoughtful approach to sustainability. The team fully understands data-driven metrics that are key components in LEED certification, like Environmental Product Declarations and Health Product Declarations,” says Anthony.
Competent and diligent, the team has a green thumb for leadership beyond LEED certification. Pepper will put its proven track record as a leading general contractor for high performance and sustainability to further use consulting with the university on strategies to drive future progress on sustainability goals.
“Pepper’s culture is grounded in a proactive, resourceful and collaborative approach – a good match for Purdue’s rigor and forward-thinking innovation,” says Anthony. “This is what makes the difference in how we drive our shared goals forward: we come together with diverse skills and perspectives, communicate openly and share responsibility for collective success.”