Living Building Challenge


The Living Building Challenge (LBC) is an attempt to dramatically raise the bar from a paradigm of doing less harm to one in which we view our role as a steward and co-creator of a true Living Future. The Challenge defines the most advanced measure of sustainability in the built environment today and acts to rapidly diminish the gap between current limits and the end-game positive solutions we seek.

The Challenge is comprised of seven performance categories called Petals: Place, Water, Energy, Health & Happiness, Materials, Equity and Beauty. Petals are subdivided into a total of twenty Imperatives, each of which focuses on a specific sphere of influence.

Under the Energy + Carbon Reduction Imperative 7 of Core Green Building Certification, LBC Petal Certification and LBC Living Certification, proponents are required to achieve Embodied Carbon Reduction. Any reductions to the embodied carbon of materials for Imperative 07, Energy + Carbon Reduction are reflected in the embodied carbon offset calculation for Imperative 08, Net Positive Carbon.

For Zero Carbon Certification, projects must both reduce and offset embodied carbon impacts of both primary and interior materials.

eTool is currently listed as one of five recommended tools to conduct LCA calculations for buildings, materials, and products due to its accurate evaluations, robust methodology and data transparency. Below we’ve provided guidance on how eTool can be used to produce the information needed for LBC’s Embodied Carbon reporting.

Jump to the following sections in this post:

Scope of work

According to Living Building Challenge v4 Energy Petal Handbook, the scope of a project’s embodied carbon calculations is determined by the life cycle stages that are included. The same stages must be included in a project’s baseline and project specific calculations.
The scope of embodied carbon reduction calculations and offsets includes modules A1-A5.

eTool allows you to conduct a whole-of-life carbon assessment (life cycle stages A-D) as defined by EN 15978 standard in which embodied carbon impact of A1-A5 modules can be reported to meet Living Building Challenge requirements.

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Comparative assessment 

Living Building Challenge requires a competitive assessment being conducted (Embodied Carbon Reductions vs. a Baseline). Reductions in embodied carbon are determined based on a quantitative comparison to the embodied carbon baseline value. The only differences in the project’s final embodied carbon value and the baseline should be reductions the project team achieved. Project teams may use material type and quantity assumptions from either recently built project examples or a modelled baseline building with comparable properties to support these assumptions.

eTool fulfils this requirement by providing “Scenarios” feature, enabling the branching of design improvements for comparative LCA studies. You can develop a Baseline Design FIRST. After that, the Proposed Design can be modelled, incorporating improvement strategies to effectively illustrate the savings. 

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Service life

All projects should use a standard 60-year lifespan when calculating embodied carbon for consistency to ensure buildings with longer lifespans are not penalised for the carbon impacts of replacing materials over time.

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Materials category

For the purposes of assessing the total embodied carbon, all permanently installed materials that represent the majority of material quantities and costs associated with the project must be included. All temporary materials, building systems, interior furnishings, equipment, site work, and small or miscellaneous products are optional to include in the assessment. Table below shows the applicable building materials.

Primary materials

The foundation, structure and enclosure of a building comprise its primary materials. Project teams should identify an equivalent list of materials that is applicable to their project.

Interior materials

Project teams must demonstrate the use of interior materials that have lower embodied carbon emissions than the industry average, where sufficient embodied carbon data is available for the product category to establish a baseline. Product baselines (i.e., industry averages) are currently specified in the ILFI-approved baseline tools for the following categories:

  • Carpet
  • Ceiling tile
  • Gypsum wallboard

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Reporting requirements

For Zero Carbon Certification and the Energy + Carbon Reduction Imperative 7 of Core Green Building Certification, LBC Petal Certification and LBC Living Certification reporting purposes, Embodied Carbon Reduction Documentation and Embodied Carbon Data must be included. According to Living Building Challenge v4 Energy Petal Handbook:

  • Embodied Carbon Reduction Documentation
    • A one-to-two-page narrative describing actions taken to reduce project embodied carbon, including primary material reduction strategies and the phase(s) in which they occurred.
    • List of interior materials selected, comparing their embodied carbon value to the industry baseline. 
  • Embodied Carbon Data
    • The input assumptions and results from the selected life cycle assessment tool, showing:
      • Primary materials project embodied carbon baseline.
      • Primary materials project embodied carbon after reductions.
      • Embodied carbon of materials + construction (A1-A5) of primary and interior material

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LBC Report in eTool

Automated LBC Excel Report

To facilitate LBC reporting for our users, we have prepared an automated Excel report in eTool. You will have to create two Excel reports for comparative analysis and reporting purposes: one for the Baseline design and another for the Proposed design.

eTool’s LBC Excel report provides embodied carbon impact (A1-A5) of primary, interior and optional materials. The life cycle embodied carbon (A-D) is also included. The report categorises materials which are the closest matching Living Building Challenge category. 

In addition, the report contains the list of interior materials selected with their associated quantity and embodied carbon impact, meeting all LBC reporting requirements mentioned in the section above.

Generating the LBC Excel Report in eTool

Below are the steps to ensure that your LBC Excel Report is generated correctly from eTool:

  1. Complete modelling your LCA in eTool & get the Design certified. Note that you will need to have both Reference and Proposed designs to be certified and reported for a comparative assessment.
  2. After certification has been completed. Navigate to the ‘Reports’ tab in your Design and generate the ‘Excel Report – ILFI LBC’ report.
  3. Save the file onto your computer.

Please note that the LBC Excel report from eTool is temporarily unavailable for download. We are actively working to resolve this. In the meantime, we have included the spreadsheet link below for our users to download and use.

>>Download LBC Excel report<<

After you’ve downladed the spreadsheet, follow the following steps to use the spreadsheet:

  1. Generate & download the All Impact Details reports for both Reference and Proposed designs.
  2. Open the LBC spreadsheet
  3. Copy & paste the data from the “Data tab” sheet of the All Impact Details report into “Data” tab of LBC Excel report (***Tip: Select the first row and use “Ctrl+Shift+Left” and “Ctrl+Shift+Down” to copy all data). 
  4. If the result does not appear in the “LBC Output sheet”, go to “Working 2” and “Working 3” sheets and click “Refresh All” under the Data tab of the sheet.

Example and User Guide

An example of LBC Excel report can be found here. The results are in “LBC Output” tab. Please note that the figures in the example spreadsheet are based on a dummy project therefore should not to be used as reference.

When using the LBC Excel report, please ensure that you refer to the “Methodology” tab for the user guide as it is important to understand how the report works and troubleshooting when required. 

In the report regarding the Embodied Carbon of Interior Material Assemblies (A1-A5) table, two anticipated behaviours are outlined along with corresponding resolution methods.

1. Adding more templates 

The report contains up to 25 wall finish templates, 15 ceiling finish, 15 floor finish, and 15 partition framing templates, 10 insulation, and 10 fenestration templates. In addition to the interior material assembly templates, 4 individual elements can be accommodated in each category. The same process for reporting extra templates can be used for reporting extra elements if necessary.

If your design has more templates/elements that need to be reported, there will be RED warnings “Totals not matching, check all items are present. (Column J)” and “More than X XXX elements/templates. Add more lines“.

You can also see that the GWP of Embodied Carbon of Interior Material Assemblies (A1-A5) table does not match that of Primary, Interior and Optional Material Assemblies table while these two figures should be the same.

To solve this issue, you first need to identify the number of templates to be added by navigating to the Workings 3 sheet. In this particular example, there are 6 Wall elements while there are only 4 lines in the table. Therefore, 2 more lines need to be added.

After adding extra lines in the table, the formula in the cells above need to be copied down into the new lines. Note that the Lookup codes are (invisible) in column B. When all templates are added, you can check whether the GWP has updated. See video below.

2. Correcting material categorisation

Partition Insulation items (RICS category 2.7.1) will be reported as Partition Framing. This can be corrected in column F of the ‘Workings 2’ tab.

In the demonstration below, Internal Wall Insulation – Fibreglass/Glasswool (m3) template is allocated to Framing Templates category (Lookup code: 5.1 in column B) while it should be under Insulation Templates category (Lookup code: 5.2 in column B). 

To solve this issue, you can go column F of the ‘Workings 2’ tab to find the exact templates and reassign the correct Lookup code. After that, the “Workings 3 tab should be refreshed. The Internal Wall Insulation – Fibreglass/Glasswool (m3) template now is allocated to Insulation Templates category.

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