Embodied Carbon Scope
Embodied carbon calculations and approved carbon offsets must encompass life cycle stages A1-A5. All projects must account for the total embodied carbon emissions (tCO2e) from construction (including the energy consumed during construction) through the utilization of carbon-sequestering materials and/or through a one-time carbon offset purchase through an ILFI-approved carbon offset provider.
Total carbon calculations must reflect the built condition of the project, including any substitutions during construction or otherwise that may have resulted in deviations from design calculations. For the construction phase (A5), teams must include embodied carbon impacts from site activities (A5a) and material waste (A5w). See the Resources section of this Imperative for guidance on these calculations, which include the Royal Institution of Chartered Surveyors’ (RICS) Whole Life Carbon Assessment for the Built Environment.
Approved LCA Tools
Tools used for life cycle assessment (LCA) calculations must have the capability to complete a full cradle-to-grave analysis as defined by ISO 14044. The Institute has approved the tools listed in Table 7-2 for use by project teams to conduct LCA calculations for buildings, materials, and products. In order to increase industry understanding of the LCA process and facilitate more accurate evaluations, tools that reveal their methodology and encourage data transparency, such as the ones listed below, are preferred.
If a project team uses an approved tool that only encompasses A1-A3, another approved tool must be used to calculate the emissions associated with stages A4-A5. Project teams are responsible for using the tools appropriately and accurately, reflecting the required level of analysis based on the project type.
For more information about embodied carbon analysis and tool categories, see the “AIA-CLF Embodied Carbon Toolkit for Architects” link in the Resources.
Table 7-2 Approved LCA Tools
- Athena Impact Estimator
- BEAM Estimator
- BHoM LCA Toolkit
- Embodied Carbon in Construction Calculator (EC3)
- Environment Agency’s Carbon Planning Tool
- Cerclos (formerly eTool)
- Sphera GaBi
- One Click LCA
- One Click LCA Planetary
- OpenLCA
- Tally
LCA tools continue to develop rapidly, leading to potential discrepancies with this table as changes occur. It is the responsibility of the project team to work with the provider to ensure the tool can do the work required. Project teams may use a different tool that is comparable to at least one of the listed calculators if it is preapproved through a Request for Ruling.
EPDs and Data Accuracy
Background data used within approved LCA tools may be collected from various sources and databases. Project teams must verify that all information used in an embodied carbon assessment is as accurate as possible for the project in question, prioritizing product-specific and geographically relevant data.
Embodied carbon data should be sourced from Environmental Product Declarations provided by qualified program operators that conduct the EPD development according to ISO Standards on behalf of product manufacturers or industry organizations. All EPDs referenced in calculations must meet the protocols for scope, preparation, and verification as outlined in ISO Standard 14025. ILFI has identified the following EPD databases that project teams can use to search for materials with ISO-approved EPDs:
- EC3
- mindful Materials
- International EPD System
- Sustainable Minds
- UL SPOT
- The EPD Registry
- Eco Platform
- Institut Bauen und Umwelt e.V.
All EPDs referenced must be current at the time of product specification. Project teams must strive to utilize EPDs that are product-specific whenever possible.
When only industry-average EPDs are available, project teams are encouraged to request or advocate for product-specific data directly from manufacturers. For products without EPDs, teams should use reasonably equivalent products based on material characteristics (in terms of raw materials, transport, and manufacturing processes), sourcing, and performance to devise baseline and design case global warming impacts. Teams must provide descriptions for their reasoning and advocate to manufacturers for product-specific data. See the Resources section of this Imperative for a link to a sample advocacy letter.
Reference Study Period
(Section previously titled Lifespan, relocated from Embodied Carbon Offset Clarifications)
All projects must use a standard 60-year reference study period when calculating embodied carbon for reporting consistency and industry alignment and as best practice to ensure buildings with longer life spans are not penalized for the carbon impacts of replacing materials over time.
