Living Building Challenge

The Living Building Challenge (LBC) establishes the most rigorous standards in the world in a variety of categories including site impacts, energy, water, materials, and resources. Perhaps most notably, it concerns itself equally with issues of beauty and inspiration, human equity, health, and happiness. Philosophically, there is strong alignment between the goals of the LBC and the mission of the Divinity School: to promote true stewardship, community, and an equitable, just world for all. The Living Building Challenge begins by asking a simple but profound question:

“What if every act of design and construction made the world a better place?”

Performance “Petals”

The LBC is comprised of seven performance categories called “Petals” which are subdivided into a total of twenty imperatives. These imperatives are applied to every type of building project no matter its size or location. All imperatives must be met in order for a project to qualify as a Living Building. For more information please refer to the website of the International Living Future Institute (ILFI),

Challenge “Petals”

    PLACE: Restoring a Healthy Interrelationship with Nature

    The Place Petal aims to realign the relationship of projects and people to their natural environment. This petal articulates where it is acceptable to build, and outlines how to protect and restore the site, create pedestrian oriented communities, and encourage local agriculture. It includes imperatives 01-04.


    • The Living Transect for the Project is L3, Village or Campus Zone.
    • The project area for the Living Village is approximately 185,677 square feet, or 4.26 acres.



    The intent of this imperative is to protect wild and ecologically significant places and encourage ecological regeneration and enhanced function of the communities and places where projects are built.


    Projects must not be built in sensitive habitats. Teams must understand and work within the site’s reference habitat, enhancing ecological performance and maturing toward the reference habitat. Teams must assess and consider cultural and social equity factors in their decision making. Petrochemical pesticides and fertilizers cannot be used in the operation and maintenance of a living building.


    The Living Village will be developed on previously disturbed land within Yale’s existing campus, surrounded by campus and city development. Biological study will inform plant selection and landscape forms, enabling restoration of ecological services. The landscape plan leaves room for growth and succession, providing increased diversity and interest over time. The design team has and will continue to explore and respond to the history and culture of the YDS campus and its wider neighborhood.

    The design team has documented the existing site conditions, which are included in the Landscape Architect’s narrative. Their research identifies the broader regional ecology within the Long Island Sound Coastal Lowland ecoregion, approximately two miles southeast of the transition to the Connecticut Valley ecoregion. The site has been confirmed not prime farmland by the USDA. These ecoregions are characterized by their irregular plains with low to high hills. The team will interface with Yale’s forestry department to continue to develop species that would have originally been present and will thrive in the new Living Village without the use of petrochemical fertilizers or pesticides.

    The team will use the Society for Ecological Restoration’s Five-star method, see also: Focus – Recovery Wheel, to continue to analyze the site and begin developing the Recovery Wheel and an adaptive management plan. We will assess and map the cultural and social makeup of the community surrounding the campus, describing the assets, attributes, characteristics, needs and opportunities. We will propose a team approach to respond appropriately based on the cultural assessment, creating project-specific design processes to ensure the project and the process is inclusive. The team will continue to include the community, it serves as a resource for feedback throughout the design phases.



    The intent of this imperative is to integrate opportunities for connecting the community to locally grown fresh food.


    As the site falls within Transect L3, this imperative requires fifteen percent of the project site, or 27,852 square feet, to be used for food production.


    The landscape program includes food gardens which will be used by individual residents and, possibly, other community programs. Other forms of edible landscape are also planned. This ties perfectly with the enthusiastic legacy of the Divinity Farm program. If the area of agriculture does not meet the minimum requirement of 27,852 square feet, the project could pursue a “scale jump” and locate Urban Agriculture in another area.



    The intent of this Imperative is to protect land for other species as more and more land is taken for human use.


    For each acre of development, an equal amount of land away from the project site must be set aside in perpetuity as conservation land. This offset can be obtained through the ILFI’s Habitat Exchange program or an approved Land Trust organization.


    Upon completion of the project, preserved natural area equal to the project’s footprint will need to be purchased through the ILFI Habitat Exchange program, or an accredited land trust.



    The intent of this Imperative is to contribute toward the creation of walkable, pedestrian oriented communities that reduce the use of fossil fuel vehicles.


    Each new project should contribute toward the creation of a pedestrian-friendly community. Pedestrian routes must be improved. There must be weather protected, secure bike storage and EV charging facilities (1 per every 30 spaces). Overall impervious parking area must be limited on the site, and larger surface lots must be segmented to favor pedestrian activities. Buildings must be scaled appropriately for the community setting, and exterior landscapes must provide welcoming gathering spaces. Efforts must be made to reduce fossil fuel-powered single occupancy vehicle trips to and from the site.


    The proposed plan increases the density of the site. The program includes one covered bicycle storage space for each residential unit. There will be pedestrian pathways that connect the site to sidewalks extending into the heart of campus and create new entry sequences into the heart of SDQ. Parking will be dispersed and at the periphery, including EV charging stations. The buildings and landscape will be thoughtfully scaled to the community’s needs. Discussions to develop strategies to reduce vehicular traffic are ongoing. Engage with the Yale University Shuttle system and CT Transit to ensure service meets the needs of the Living Village.

    WATER: Net Positive Water Use

    The Water Petal seeks to realign water use with the fact that it is a precious natural resource. Negative impacts of wastewater and stormwater to downstream systems should be avoided as well. This is a petal that touches on landscape planning, building engineering, and human behavior in profound ways. This petal includes Imperatives 05 and 06.



    The intent of this imperative is to encourage projects to treat water like a precious resource, minimizing waste and the use of potable water, while avoiding downstream impacts and pollution.


    This imperative requires avoidance of potable water for irrigation, significant (50%) reduction of water use from a modeled baseline, and management of stormwater on site.


    The project will achieve these requirements through careful selection of water fixtures, and through reuse of wastewater.



    The intent of this imperative is for project water use and release to work in harmony with the natural water flows of the site and its surroundings.


    Water use and its release into the environment must work in harmony with the natural conditions of the site. All stormwater and water discharge must be treated and managed on site while wastewater must be infiltrated on site or offset through metered handprinting.


    Refer to “Focus – Net Positive Water”, “Focus – Storm Water”, and to Civil and Water Systems narratives

    ENERGY: Net Positive Energy Use


    The Energy Petal signals a new age in which the built environment relies solely on renewable forms of energy, operates year-round, and does not emit pollution. Reduction and optimization of energy use are prioritized in order to eliminate wasteful consumption of resources and money. This petal includes Imperatives 06 and 07.


    The intent of this imperative is to treat energy as a precious resource and minimize carbon emissions that contribute to climate change.


    The buildings must achieve a 70% reduction in total net annual energy consumption (after accounting

    for on-site renewable power), as compared to a typical building with comparable climate, size, use, and occupancy. There is to be no on-site combustion. Projects must meter energy use at a granular level, allowing diagnosis and feedback to perform efficiently. New projects must demonstrate a 20% reduction in the embodied carbon of primary materials compared to an equivalent baseline, refer also to Focus – Embodied Carbon. All projects must select interior materials with lower than industry average carbon footprint for product categories for which embodied carbon data is readily available (carpet, ceiling tile, gypsum wallboard).


    Net Positive energy systems will include passive design strategies, exemplary high-performance building envelopes, and efficient mechanical and electrical systems. The target range for Energy Use Intensity (EUI) is 24.4kbtu/sqft-yr, a goal that reduces energy by over 70% when accounting for on-site renewables according to the Zero Tool. The design will have best-in-class building energy performance systems to meet this target range and include systems that influence use and behavior patterns. The project will meet the active energy requirements with the following systems as defined in the mechanical narrative:

    • VRF heating and cooling (all electric)
    • Dedicated Outside Air Systems
    • Exhaust Air Heat Recovery
    • Occupancy and Demand Controlled HVAC
    • Temperature Setback and Optimized Warm-up
    • Low Pressure Drop Air Handlers and Duct Systems/Coil Bypass Dampers
    • Mixed Mode Natural Ventilation
    • Extensive Use of Variable Flow Systems
    • DDC-Based Building Management System (BMS) with Metering Capabilities

    The project is using a life cycle assessment tool called Tally to analyze the embodied carbon of building design and set a baseline for comparison. At this stage, the project has identified the following strategies to lower the embodied carbon of primary materials:

    • Structure: FSC certified timber and light wood framing will be used throughout.
    • Enclosure: Predominantly insulate using cellulose. Select cladding materials that are natural and have low embodied carbon over their life cycle. Currently the team is studying terracotta, a durable cladding material with lower embodied carbon compared to aluminum, steel, glass, and concrete. Its largest impacts are typically the aluminum systems used to support the product so with smart detailing, embodied carbon could be reduced further.

    In addition, the team will select a natural interior finishes palette, using Tally and the EC3 tool to identify lower-than-average materials for carpet, ceiling tile, and gypsum wallboard when those selections are made. Refer also to the “Focus – Embodied Carbon” section of this report which includes additional areas for exploration of embodied carbon reductions, including in foundations, masonry, and metals.



    The intent of this imperative is to foster the development and use of carbon-free renewable energy resources while avoiding the negative impacts of fossil fuel use, primarily the emissions that contribute to global climate change.


    The project must supply one hundred and five percent of their project’s energy needs through on-site renewable energy on a net annual basis, without the use of combustion. The project must sub-meter major energy end uses. The total embodied carbon emissions (tCO2e) from construction (including the energy consumed during construction) must be offset through the utilization of carbon sequestering materials and/or through a one-time carbon offset purchase through an ILFI-approved carbon offset provider. The project must develop and incorporate a resilience strategy to allow the building to be habitable for one week, or otherwise participate in support for the local community in a disaster, through the use of batteries, storage, or other approved strategies, refer also to Focus – Resilience and Battery Backup.


    Through reductions of energy use (see the approach to Imperative 07 above) the project will minimize energy required. The project will provide solar arrays that provide 105% of the project’s annual needs. Available roof space will be optimized to provide most or all of this array. Any additional power need will be provided through solar canopies, or offsite. The project will provide submeters to track energy used for heating, cooling, lighting, fans/pumps, plug loads, vertical transportation and domestic hot water. This will allow for study and optimization of energy use over the long term.

    Upon completion, the Divinity School will purchase carbon credits to offset the project’s embodied carbon that is modeled through Tally with additional inputs for solar and other items not in the scope of the Tally model.

    HEALTH & HAPPINESS: Optimize Well Being

    Substandard environmental conditions have significant impacts on human health and potential. The Health and Happiness Petal focuses attention on creating robust and healthy spaces to optimize human well-being. It includes Imperatives 09-11.



    The intent of these imperatives is to promote good indoor air quality and a healthy interior environment for project occupants and to demonstrate ongoing high-quality indoor air. Imperative   09’s requirements are exceeded by those of Imperative 10, so we list only those requirements here.

    The project must have exemplary indoor air quality. This entails a smoking ban within the project boundary, dedicated exhaust systems, entry track off systems, use of green cleaning products, and mandatory indoor air testing.


    The building must have a ventilation system that complies with ASHRAE 62. Outside views and daylight must be available in at least 95% of regularly occupied spaces. Kitchens, baths, and janitorial areas must have direct exhaust. The buildings must have a healthy indoor environment plan to address cleaning, management of cleaning at entryways, and other air quality improvement strategies. Smoking is not allowed inside or within 25 feet of building openings. Indoor Air Quality testing must be conducted after occupancy. Key interior materials must be tested to comply with CDPH Standard Method v.1.-2010. Occupants must have control over their thermal comfort, including operable windows.


    The project will provide exemplary indoor air quality. All required strategies are incorporated in the current design. Regularly occupied rooms will have ample access to outdoor views and natural light. Windows will be operable. Every regularly occupied space will need to have operable windows to provide access to fresh air and sunlight. The sizes and shapes of the buildings in the framework plan lend themselves to perimeter windows.



    The intent of this imperative is to provide opportunities for project occupants to directly connect to nature, and to assess the success of the Health + Happiness Imperatives.


    The projects must connect people and nature through the provision of sufficient and frequent human nature interactions in both the interior and the exterior of the project to connect the majority of occupants with nature directly. The projects must complete a post-occupancy evaluation that addresses the health benefits of the project including the benefits of daylight, fresh air and access to nature at least once within six to twelve months of occupancy.


    Careful design will provide ample opportunities for human-nature connections. The team will support YDS in its post-occupancy evaluation to gather information on residents’ feelings about the building’s design and function. The results of the biophilia charette required in the Beauty petal will provide inspiration here as well.

    MATERIALS: Safe for all Species Through Time

    The intent of the Materials Petal is to foster a materials economy that is non-toxic, transparent, and socially equitable. The imperatives in this section “aim to remove the worst known offending materials and practices,” and also to acknowledge the obligation to offset damaging consequences associated with the construction process. The Materials Petal meets and exceeds LEED as well as Yale’s Design Standards, which are based on LEED criteria. It includes Imperatives 12-15, though Imperative 12 is superseded by the requirements of 13-15 for projects pursuing Living Certification and is therefore not referenced here.



    The intent of this Imperative is to foster a transparent materials economy free of toxins and harmful chemicals.


    The team has begun materials vetting on selected materials, and tracking that process using Red2Green. This will continue through CDs and into procurement for performance based or alternate materials.


    This imperative may require deviations from Yale’s typical specifications and construction process.

    • All materials and products will need to be reviewed for ingredient compliance in addition to performance.
    • Architects & contractors may need to use products and materials different from the norms or standards for doors, windows, plumbing fixtures, electrical wires, cables, tapes, sealants,

    etc. Yale specifications are being reviewed as products are selected and vetted, with Yale standard products being reviewed first. If specific manufacturers and products that are called out in standards contain Red List chemicals, they will need to be replaced by equivalent products that comply with the imperative. 



    The intent of this imperative is to support sustainable and socially just extraction of materials and transparent labeling of products.


    A minimum of 80% of wood must be certified by the Forest Stewardship Council (FSC), be from salvaged sources, or be deliberately harvested onsite. Twenty products from the Declare database (a product transparency initiative) must be incorporated into the project. The Project Team must send Declare program information to those manufacturers not yet in Declare. The team must incorporate four products with Living Product Challenge certification. Finally, the Project Team must advocate for the creation or adoption of third-party standards for sustainable resource extraction and fair labor practices for stone, rock, and metals.


    The team will apply its experience and will work with the CM to ensure that all LBC materials procurement requirements are achieved. The team has begun to identify Declare listed products in lighting, and division 07,14. Responsible Sourcing among other places and has included living products as basis of design for louvers.



    The intent of this imperative is to foster local communities and businesses, while minimizing transportation impacts.


    Manufacturer location of materials and services must adhere to a set of distance criteria based on the material construction costs. At least twenty percent of the construction material budget must be sourced from within 500 km (311 mi) of the site, followed by an additional thirty percent from within 1,000 km (621 mi), twenty-five percent from within 5,000 km (3,107 mi), and twenty-five percent from any location.


    The team plans to use the upcoming design development estimate as a basis for developing a model for achievement of this imperative. Close work with the CM will be important to the achievement of this imperative.


    This imperative may require deviations from Yale’s typical construction process. All material and products are reviewed for distance from project site to manufacturing location. Architect and CM may need to use products and materials that are different from Yale’s norms or standards to comply with the requirement for local sourcing.



    The intent of this imperative is to integrate waste reduction into all phases of projects and to encourage imaginative reuse of salvaged “waste” materials.


    Careful planning must ensure that waste is kept to a minimum, and that material leaving the site is not landfilled or incinerated. Specific minimum diversion rates must be met. Projects must salvage one material per 500m2. Projects must develop infrastructure for collecting recyclables and compostable food scraps.


    As the project develops, the team will need to outline options for waste diversion and minimization with the selected construction manager, as well as combustion avoidance. If possible, existing building materials should be deconstructed instead of demolished. During design, the Project Team will prepare a conservation management plan that will address material durability, end-of-life, and adaptive reuse strategies.

    EQUITY: Supporting a Just and Equitable World


    The intent of the Equity Petal is to foster an inclusive, just, and equitable community. A truly inclusive and fair society is one that is empowered to protect and restore civilization. This petal includes Imperatives 17-18.



    The intent of this imperative is to allow equitable access to and protections from any negative impacts resulting from the development of Living Building projects.


    All externally focused roads and non-building infrastructure must be equally accessible by all members of the public regardless of background, age, ability, and class—including the homeless with reasonable steps taken to ensure that all people can benefit from the project’s creation.

    YDS is within Transect L3, so it must provide for, and enhance the public realm through design measures and features that are accessible to all members of society, such as street furniture, public art, gardens, and benches.

    The project must safeguard access for those with physical disabilities through designs meeting the 7 Principles of Universal design (United States Access Board), the Americans with Disabilities Act (ADA), and the Architectural Barriers Act (ABA) Accessibility Guidelines.

    The project may not block access to, nor diminish the quality of, fresh air, sunlight, and natural waterways for any member of society or adjacent developments. The team must also appropriately address any noise audible to the public.


    The project includes universally accessible furniture, public art, gardens, and benches in the landscape. Within the proposed Design Framework, the Living Village can be sited so that at winter solstice, buildings will not cast shadows onto off-site facades above the six meter mark.



    The intent of this imperative is to help create stable, safe, and high-paying job opportunities for people in the local community, and support local, diverse businesses through hiring, purchasing, and workforce development practices.


    Two project team organizations must have a JUST label, and an additional five organizations must complete a JUST Self-Assessment. In addition: The project must include diverse stakeholders from vulnerable or disadvantaged populations in the design, construction, operations and maintenance phases at prescribed levels:

    • 20% of design/construction contracts and 10% of maintenance contracts must be with JUST organizations or Minority, Woman or Disadvantaged Business Enterprises (MWDBE) organizations. And 10% of General Contractor’s contracts and/or maintenance contracts.


    • Donate 0.1% of total project cost to a regional, community-based nonprofit organizations focused on equity and inclusion.


    During CD, the team will study whether 20% of design, construction, or combined fees will/can be procured from JUST or MWDBE firms. If not, the project will make a donation of 0.1% of total project cost to meet this requirement. Three current firms have JUST labels, and four additional firms must study the process to evaluate their participation.

    BEAUTY: Uplifting the Human Spirit

    The intent of the Beauty Petal is to bring attention to the need for beauty as a precursor to the creation of robust, healthy spaces. This petal includes Imperatives 19 and 20.



    The intent of this imperative is to connect teams and occupants with the benefits of biophilia and incorporate meaningful biophilic design elements into the project.


    The project must contain features “intended solely for human delight” which celebrate culture, spirit, and place. The project must incorporate public art. Project teams must conduct one or multiple biophilic workshops that total of 8 hours that result in a biophilic framework and plan. See also Biophilic narrative on the following pages.


    A biophilic workshop conducted during the schematic design phase resulted in a biophilic framework and plan that will be updated with future biophilic workshops. These themes have informed design development and are built upon in each design meeting and presentation. Further, the Divinity School is actively engaging with student and outside groups to commission public art to be located on site and celebrate the indigenous peoples of the region.



    The intent of this Imperative is to provide educational materials about the operation and performance of the project to the occupants and the public in order to share successful solutions and catalyze broader change.


    The project must develop a case study, a brochure, interpretive signage, and an educational website.

    The project must be open to the public for tours at least one day per year (as appropriate to its use).

    The team must share its Operations and Maintenance manual with ILFI, and it must include at least one Living Future Accredited professional. The project must provide educational materials about its operation and performance to the public. The intention is to share successful solutions and motivate others.


    At completion, the project team will share the required information via the formats prescribed. A public tour schedule will be established and maintained. IES provides a LFA-accredited professional to the team.

    Indicators for Success

    The LBC seeks to create buildings that go beyond the most rigorous existing environmental standards such as LEED certification. Living buildings would not only be sustainable, but would actually contribute to the environment. A living building gives more than it takes.

    A graph showing the living building challenge indicators of success. From the left are negative environmental impacts indicated by a bottom oriented orange curve that spans across existing building standards in order of least regenerative to most from the left. Starting with existing Building Code, then Green Standards, then High Performance Standards almost att he middle. Just past the middle to the right is the Sustainable Standard which starts the Living Building Challenge level indicated by a top green curve labeled Positive Environmental Impacts.
    “Setting the Ideal as the Indicator of Success” graph from the Living Building Challenge 4.0



    The Yale Divinity School has chosen the world’s most stringent and progressive green building standards to guide the overall village design and construction process – The Living Building Challenge. Doing so makes evident our leading commitment to ecological responsibility. In committing to be the first Divinity school in the world to achieve these notable accomplishments (and one of the first in the world of any project type to meet the laudable performance goals of the criteria) we intend to show communities around the world how these standards are possible, and what benefits accrue to those who live work and learn in such places. At this stage in the project, the team has developed an approach to each of the 19 Living Building Challenge Imperatives. In the following sections, we highlight and summarize those that have evolved significantly since the schematic design. In addition, we call out those that are the subject of active discussions with ILFI to align project intent with LBC requirements. The LBC design process will continue through the next phase, yielding a clear plan to achieve all intended Petals. The sections that follow these areas of focus provide an overview for achievement of the remaining petals and imperatives.


    Rainwater catchment and treatment systems for potable water of this scale entail significant regulatory requirements. From a regulatory standpoint, such a system is treated as a public water supply, and for one of this scale regulations and general public health would require chemical treatment. Our team has past experience with non-chlorinated potable water systems of this size, and they simply don’t function adequately and are unable to maintain levels of water quality required for a public water supply. Given that a chemical treatment system is essentially redundant with

    existing city infrastructure, we would ask ILFI to allow a ‘handprinting’ approach to potable water. In such an approach, the resources that would otherwise be devoted to the redundant chemical treatment system within the project would instead be used to improve the community potable water system. Yale Divinity School is deeply connected to the community, and using this part of the

    Living Building Challenge scope to improve the potable water access and quality at the community level enhances those ties, strengthens the importance of equity, and follows the spirit of the Living Building Challenge.


    The project site is located in an area with bedrock ledges close to the surface and relatively impermeable soil. The project will infiltrate as much as possible and will significantly exceed code requirements. In fact, modeling of the current landscape design and stormwater management system shows that the project outperforms the pre-colonial forested condition for two, one-hundred-year storm events, both in terms of peak discharge rates and overall discharge volume. The project does not achieve the 98% annual average infiltration rate required in the Water Petal. The project will present the full stormwater analysis to ILFI to confirm compliance with certification intent, while recognizing that when actual site conditions preclude this, the project’s approach will be regarded as appropriate.


    Imperative 08: Net Positive Energy requires projects to develop and implement a resilience plan, enabling one week of building habitability in the event of a disaster. The team has studied this requirement and has determined that the Yale campus grid, with its redundant grid and power islanding capability, meets a portion of the requirement. We have further determined the size and ecological cost of a battery backup that would meet the letter of LBC requirements. Based upon the location of the project within the campus grid, a new battery would have limited utility for the building and the larger community.

    This project exists within the infrastructure of the Yale campus and will be connected to the Yale power loop. Because of the nature of that connection, a battery array within the project (as required by LBC for energy resilience) would be incapable of being used for general grid regulation, so would only be of use during long-term grid outages. Such outages are rare in New Haven, so the battery array would rarely be of any use.

    We expect a battery system to operate in two modes. Under normal conditions, the system is tied to the building’s main switchboard and will charge/discharge per a control system to reduce building demand/consumption as well as discharge overnight when PV system output is not available. This is a programmable control system and can be set up to operate in a number of different settings while

    monitoring building demand/consumption and PV output. The second mode of operation is under a sustained power outage. During an outage, the battery and PV system will operate in an island mode, with connection to the Yale power grid disconnected. Non-essential loads will be manually disconnected from the building distribution. The remaining loads, minimized to maintain habitability only, will be fed with power from the combination of PV and battery output. The Yale campus electric distribution system is robust, arranged with dual radial feeders to this building. The entire campus is served with four utility feeders and Yale operates a cogeneration plant that can island the campus from the utility and operate during a utility outage. A sustained outage of multiple days is a highly unlikely event considering the level of reliability built into the campus electrical network.



    All project teams must document site and community conditions prior to the start of work

    including, but not limited to, identification of the project’s Reference Habitat. All projects must demonstrate that they contribute positively to the ecology of place and restore or enhance the ecological performance of the site toward a healthy ecological baseline. On-site landscape must be designed to mature and evolve, and to emulate the functionality of the Reference Habitat, as appropriate to the project’s Transect.


    The project looks to two nearby upland parks (East Rock and West Rock) to find reference habitat. These are rocky areas with pockets of good soil. The canopied forests are dominated by oak trees, with a mixture of other hardwoods and softwoods and a rich understory of other species.


    The current site is dominated by a paved parking lot. Qualitatively, the project site has little to no functional ecological systems. There are sporadic trees of little ecological value on the perimeter, and weeds in the cracks in the pavement.


    The recovery wheel methodology asks for assessment of six attribute classes:

    1.0 ABSENCE OF THREATS (4 stars): The site begins with 3 stars: all adjacent threats managed or mitigated to a low extent. The site is bordered by a public school and by other Yale-owned properties. It is at the highest point of the surrounding land, so no runoff from neighbors

    has a negative impact on site conditions. We believe that coordination with the neighbors and further development of adjoining Yale parcels in future phases will add one star to this condition. This will never be a pristine ecosystem, but its connections to neighboring parcels can be enhanced. Ailanthus altissima is present, which is the host plant for the invasive Spotted Lanternfly.

    2.0 PHYSICAL CONDITIONS (4 stars): The soils are compacted under asphalt, so we see the current condition as one star. We think over time the project can reach 4 stars, with healthy soils that support growth of introduced plants and recruit additional species to the site.

    3.0 SPECIES COMPOSITION (3 or 4 stars): We assess the site to have one star currently: it shows less than 2% of the biodiversity of the reference habitat. There are a few invasives that appear in the tree survey along the northern border. We aim for three to four stars, targeting 25-60% of the biodiversity found in nearby healthy forests. This is limited, in part, by the density and programming of the project area. The tight site will have all typical regional strata present.

    4.0 COMMUNITY/STRUCTURE (3 or 4 stars): The site begins with one star: there is no spatial patterning nor are there complex interspecies relationships evident on site. We target three or four stars, with a plan to introduce key native species that will become the scaffold for further

    ecological community development.

    5.0 ECOSYSTEM FUNCTIONALITY (4 stars): The site begins with one star: the soils are a foundation to support ecological remediation. We target four stars, creating a site that displays key ecological functions, and which can recruit and disperse native species.

    6.0 EXTERNAL EXCHANGES (4 stars): The site begins with one star: there is the potential for exchange of water and species with neighboring sites, but no evidence of fruitful activity. We target four stars, a high level of connectivity within the bioregion, and careful control to ensure that invasive species do not use the site as an area from which to spread further.

    The before and after images of this site will be remarkable. The goals for ecosystem function on the site are only limited by its relatively small size, and the fact that a significant portion of the site will be occupied by building, hardscape, and program areas that will be beautiful and functional, but that cannot support the full range of biodiversity evident in the reference habitat.


    IES has engaged with the design team to train them on how to most efficiently achieve the LBC materials objectives. The process will accelerate through the balance of design, leading to specifications that provide clear LBC compliance information to the construction team.

    Product Line Entries: 238

    Approved products: 63

    Known conflicts with the Yale’s Design Standard: 1

    • GCP Applied Technologies is the Yale preferred manufacturer for air and vapor barrier membranes. In our experience, GCP has many LBC Non-Compliant products. Other manufacturers, such as Prosoco and Henry, have Declare labeled products (fully transparent and Red List free) for several product types.

    Next Steps: IES will continue to work with the design team to identify Product Types and products for potential inclusion in the specifications.



    The purpose of this section is to describe the impact of upfront embodied carbon, or UEC, on the greenhouse gas (GHG) emissions profile for the Design Development set of the Living Village project at the Yale Divinity School. Upfront embodied carbon includes the GHG emissions of the building materials, their transportation to site, and the construction process – all emissions prior to building occupancy. In this section, we will define the UEC baseline against which the project’s UEC emissions are evaluated. We will then present the reporting of the estimated UEC emissions for the design, and the role that carbon storage in biogenic materials plays in the design strategy and accounting. Finally, we will explore what strategies have proven successful in achieving low UEC emissions in the project thus far, and opportunities for further reductions to ensure the design meets the project goals for UEC emission reductions.


    This project is being designed to meet the standards of the International Living Future Institute’s Living Building Challenge program. Program requirements regarding GHG emissions for the design include the following requirements for UEC emissions:

    • 20% reduction against a baseline emissions rate

    • A maximum UEC of 500 kg CO2e/m2 of building. Note that all GHG emissions are calculated as their equivalent impact as that of carbon dioxide, and the metric “kg CO2e” reflects the mass of all GHGs. The metric defined here, “kg CO2e/m2”, is the amount of GHG emissions per square meter of building – in this case, specifically UEC emissions.

    The establishment of a baseline emissions value is a required task of the project team in pursuit of meeting the 20% reduction requirement. As the industry is still early in the process of developing sufficient data to accurately establish baselines for different project types relevant to specific project locations, this task is in and of itself a challenge. Using a 2017 Embodied Carbon Benchmarking research study conducted by the Carbon Leadership Forum, the project team has established a UEC baseline of 504 kg CO2e/m2 for a project of this type. The methodology behind the development of this baseline is available upon request, and will be presented in the final project report at the conclusion of the design process.


    The Design Development model of this building shows an estimated UEC of 1,580,00 kg CO2e; the Upfront Carbon Use Intensity (uCUI), which is the UEC per square meter of building(as described above), is 409 kg CO2e/m2. This value comes within 1% of the “20% reduction below baseline” LBC program requirement, and comfortably within the total emissions cap. This value gives no carbon storage credit to any of the wood being used in the building, which is a conservative approach taken prior to confirming the sourcing and procurement of certified wood products; this is described further below. Carbon storage credit is given to the cellulose insulation, which as a recycled paper product, can be valued for the carbon in the material that is being diverted from the waste stream and, ultimately the atmosphere, and is effectively stored in the building. A full accounting of the UEC emissions for the project will be included in the final report.


    The requirements of the LBC program dictate that 80% of wood products must be sourced from Forest Stewardship Council (FSC)-certified forests and supply chains. This provision, under their “Responsible Sourcing” imperative, is designed to ensure responsible forest management practices to reduce deforestation, erosion, poor water quality, illegal logging, and other related impacts. Similarly, the LBC program allows FSC-certified wood products to claim a carbon storage benefit in the accounting of UEC for the project. The carbon mass in the wood was originally photosynthesized from the atmosphere and is kept bound in the building material throughout the material’s life span and prevented from returning to the atmosphere through decomposition or incineration. Therefore, a “negative emission” equivalent to the amount of CO2 that was photosynthesized to grow the wood mass can be applied to the accounting of UEC for the design. Note that end-of-life scenarios may see this carbon re-enter the atmosphere, and the time boundaries of the analysis and end-of-life
    conditions of the material will impact the accounting of stored carbon. In the case of wood products, to ensure that carbon benefits aren’t assigned to products that come from poorly managed forests or otherwise ecologically destructive supply chains, only stored carbon from FSC-certified wood products are recognized by the LBC program in UEC accounting.


    To that end, when including carbon storage values for 80% of the wood products in the building, the estimated UEC values are reduced to 720,000 kg CO2e, or 186 kg COe/m2 – far below the requirements of the LBC project. This highlights the significant role that the use of sustainably sourced wood products plays in the strategy to reduce the GHG emissions of this project, and the role of biogenic carbon storage in achieving low-carbon construction goals in general. The use of cellulose insulation is another valuable source of carbon storage in the building. Key carbon reduction strategies such as reduced use of carbon-intensive structural materials such as steel and concrete, as well as reductions/eliminations of carbon-intensive insulation and finish materials, all help contribute to a low-carbon building that stands to meet the requirements of the LBC program, providing that continuity of these design strategies is carried through final design and procurement. Please see accompanying materials for a complete summary of the DD-level UEC accounting for the project.


    Looking ahead to the final design and procurement phases, the project will be well-served by identifying which wood products can be sourced from FSC-certified supply chains in both availability and cost and considering those carefully in specifications in advance of final UEC accounting. Further, a list of additional emission reduction opportunities has been identified. A primary opportunity lies in the formulation of low-emission concrete through the use of supplementary cementitious materials to reduce the use of carbon-intensive Portland cement. Using high-recycled content metals such as steel and aluminum is another effective approach. Even product selections of low-emission gypsum wall board and acoustic insulation can significantly reduce the emissions profile of the building, primarily due to the significant mass of these materials used in the building. The project team will be evaluating the impacts of these and other material solutions throughout the final stages of design and procurement in pursuit of a low-carbon building that both meets the standards of the LBC program and addresses the owner’s imperative to address the climate impact of their project.