LCA in Building Standards and Certification Systems
A number of whole building standards and certification systems include life cycle assessment as a factor in evaluating building sustainability. Each has a specific goal (stated or implicit), such as reducing greenhouse gas emissions or improving indoor environmental quality. Overall discussion and reviews of these systems can be found at the Whole Building Design Guide.
Provisions for life cycle assessment metrics are found in Section 9, Materials and Resources. To be compliant, a building may meet one of several options in the Prescriptive path requirements (9.4, Reduced Impact Materials). Section 18.104.22.168 Multiple-Attribute Product Declaration or Certification requires installation of at least 10 products that have either a product specific EPD, industry wide EPD, multi-attribute certification, or product LCA.
Section 9.5 offers an alternative performance path that includes provisions for life cycle assessment metrics, procedures, and reporting. This section requires an ISO-compliant, whole building LCA that compares at least two different building alternatives, where the designed building shows either a 10% improvement in two impact categories or 5% improvement in three impact categories, one of which must be global warming potential (GWP).
The Green Globes system includes a section to compare various design options, materials, and resources through an LCA to gain points toward certification. Green Globes provides specific LCA guidance that includes using the Athena Impact Estimator or the LCA must conform to ISO 14040 and ISO 14044.
The LCA must minimally be cradle-to-grave, addressing resource extraction, manufacturing, building construction, product replacement, demolition, landfill processes, and transportation in all stages. If the assessments include operating energy, all relevant processes from energy extraction to delivery and consumption must be included.
The LEED rating system incentivizes the use of LCA and EPDs in building design and material selection by offering credits on a sliding scale of implementation.
Building Life Cycle Impact Reduction, Option 4 awards credit for conducting a whole building life cycle assessment without having to demonstrate specific impact reductions. Additional points (up to a total of 4) can be achieved if the design demonstrates 5%, 10, or 20% reductions in at least three of six environmental impact categories compared to a reference building. LEED recognizes the importance of embodied carbon by stipulating one of the three impact categories must be GWP.
Building Product Disclosure and Optimization, Option 1 Environmental Product Declarations encourages transparency and life cycle thinking in product selection by rewarding the use of products and materials with life cycle information and environmentally, economically, and socially preferable life cycle impacts. To earn the credit, at least 20 permanently-installed products must have ISO-compliant EPDs that are cradle-to-gate in scope (from raw material extraction through manufacture).
BREEAM (Building Research Establishment's Environmental Assessment Method)
The BREEAM building rating system strives to encourage practices that can reduce the impact of construction materials throughout design, construction, maintenance, and repair. Section 10, Materials, awards up to 10 points to recognize and encourage the use of life cycle assessment tools to specify and source construction materials with low environmental impact over the life cycle of the building. To achieve an exemplary score, at least 10 installed products must be covered by a verified, manufacturer-specific EPD.
The Living Building Challenge promotes sustainable–and even regenerative–buildings through 20 imperatives. Imperative 14, Responsible Sourcing, requires the selection of materials that come from environmentally responsible sources. To claim compliance with this imperative, non-residential projects must incorporate one product certified under the Living Product Challenge per 1,000 square meters of gross building area. The Living Product Challenge incorporates both life cycle analysis and material health evaluation in order for manufacturers to create products that are a net benefit across their life cycle.