Credit OverviewA summary of the credit requirements

Documentation InstructionGuidance for creating the credit submission

Best PracticesTips for integrating Tally into a design workflow, including the creation of a baseline building

Submission Guide for Building Life Cycle Impact Reduction Credit, Option 4

2 © KT INNOVATIONS

This guide was developed by KT Innovations, developer of Tally® software and affiliate of KieranTimberlake, an award-winning architecture firm dedicated to advancing building design practices through material, system, process, and environment-driven questions.

KT Innovations wishes to thank the United States Green Building Council for providing feedback on this guide.

To learn more about Tally, visit www.choosetally.com, or send email queries to support@choosetally.com.

Acknowledgements

ACKNOWLEDGEMENTS

3 © KT INNOVATIONSINTRODUCTION

This guide will help you use Tally to achieve the LEED v4 Building Life Cycle Impact Reduction Credit, Option 4, called Whole Building Life Cycle Assessment.

In the guide, we provide an overview of the credit and step-by-step instructions to create a credit submission based on an editable Documentation Template. Finally, we share best practices for working with Tally to facilitate credit documentation.

Introduction

4 © KT INNOVATIONS

Credit Scope

Option 4 rewards projects that reduce the environmental impacts of materials and processes across a building’s full life cycle, using an expected life of 60 years. The required life cycle phases, collectively referred to as cradle-to-grave assessment, include:

• Resource extraction • Manufacturing• On-site construction• Maintenance and replacement• Deconstruction• Demolition• Disposal

While the scope includes the full life cycle of a building, it does not require that all building elements are modeled. Option 4 defines the following scope:

Included• Superstructure and envelope

• Footings and foundations

• Structural wall assembly (cladding to interior finishes)

• Structural floors and ceilings

• Parking structures

• Roof assemblies

Excluded• Excavation and site development

• Interior nonstructural walls or finishes*

• Finishes on structural floors and ceilings

• Furnishings and casework

• Electrical and mechanical equipment and controls, plumbing fixtures, fire detection and alarm system fixtures, elevators, conveying systems

• Surface parking lots

* Interior partitions and finishes are not required, but may be included at the discretion of the project team

Credit Overview

CREDIT OVERVIEW

Life cycle stages and model scope are described in detail in ISO Standard 21930.

5 © KT INNOVATIONS

Credit ThresholdA total of three points are awarded when the following criteria are met:

1. The proposed design must not increase any impact category by more than 5% as compared to the baseline building.

2. The proposed building design must reduce Global Warming Potential and at least two additional impact categories by a minimum of 10% when compared to the baseline building.

While not required to achieve the credit, an extra point for exemplary performance is awarded if the proposed design reduces the environmental impacts of all six impact categories by a minimum of 10% as compared to the baseline building.

Further, in certain regions the credit is a Regional Priority Credit and will be awarded an additional point, for a maximum of five points.

Impact CategoriesWith Life Cycle Assessment, we quantify the environmental impacts of materials in terms of impact categories. The impact categories required by Option 4 are as follows:

• Global Warming Potential• Ozone Depletion Potential• Acidification Potential• Eutrophication Potential• Formation of Tropospheric Ozone • Non-Renewable Energy Consumption

Baseline BuildingOption 4 measures reductions in environmental impacts as compared to a baseline building. The baseline building must be the same in function, gross floor area, orientation and approximate operational energy use as the proposed building. As there are presently no existing databases of LCA results to provide baseline performance, design teams must establish and model their own baseline for comparison.

CREDIT OVERVIEW

See page thirteen of this guide for a straightforward approach to creating a baseline building.

Use LEED’s Regional Priority Credit Lookup tool to check.

Credit Overviewcontinued

6 © KT INNOVATIONS

Option 4 Submission Requirements include:

1. Life Cycle Assessment Impact Measures Table2. Description of the Baseline Building3. Description of the Proposed Building4. Supporting Documents5. Special Circumstances

Use Tally to create the submission for Option 4. Refer to the editable Documentation Template which contains sample text and tables to help you streamline your workflow.

Documentation Instruction

DOCUMENTATION INSTRUCTION

Life Cycle Assessment Impact Measures Table

This part of the submission asks you to quantitatively summarize the reductions to environmental impacts that your project has achieved.

Fill out the Baseline Building Value column and the Proposed Building Value column based on the spreadhseet reported by Tally.These values and their respective units can be found in the Grand Total row in the spreadsheet generated by Tally.

Figure 1. Populate the Impact Measures Table with values from the Grand Total row from the spreadsheets generated by running Tally on the Baseline and Proposed cases.

7 © KT INNOVATIONS

In order to achieve the credit, at least three of the six categories, including Global Warming Potential, must achieve this 10% reduction, and none of the impact categories may increase by more than 5%.

Calculate and fill out the Percent Reduction field.

Calculate the Percent Reduction field using the baseline and proposed building values and the following formula:

Fill out the Number of Measures row.Complete the cell in the lower right by counting the number of impact categories that have a percent reduction of greater than 10%. The units in the table reflect the units reported directly from Tally.

This table is pulled directly from the credit submission form to facilitate easy tracking of these values prior to credit submission.

DOCUMENTATION INSTRUCTION

LEED Metric equivalent Tally metric

Baseline Building Value

Proposed Building Value

Units Percent Reduction (%)

Global Warming Potential GHG Global Warming Potential

CO2e

Stratospheric Ozone Depletion Ozone Depletion Potential

kg CFC -11

Acidification of Land and Water Acidification Potential

kgSO2

Eutrophication Eutrophication Potential

kg N

Tropospheric Ozone Formation Smog Formation Potential

kgO3

Depletion of non-renewable energy sources Non-Renewable Energy

MJ

Number of Measures with at least a 10% reduction

Baseline Building Value - Proposed Building Value

Baseline Building Value

Life Cycle Assessment Impact Measures Tablecontinued

8 © KT INNOVATIONS

Figure 3. Example of optional graphic showing overall reductions achieved.Source FIle: https://boom.kierantimberlake.com/project/855/Documents1/855%20Research/UW%20Full-Building%20LCA.docx?Web=1Caption (for reference): Whole Building LCA Comparison to Baseline Case for LEEDv4

0%

50%

100%

Option 1 - Design CaseOption 2 - Baseline Case

Design Options

73%

41%

71%

79%76% 74% 74% 75%

AcidificationPotential

1 2Eutrophication

PotentialGlobal Warming

PotentialOzone Depletion

PotentialSmog Formation

PotentialPrimary Energy

DemandNon-renewable

EnergyRenewable

Energy

1 2 1 2 1 2 1 2 1 2 1 2 1 2

While not required for documentation, a graph can help you make your case.

DOCUMENTATION INSTRUCTION

Include a graph to show overall impact reductions.Provide a graphic representation of the data from the Life Cycle Assessment Impact Measures Table, showing the values of the impact categories in the baseline and proposed conditions for each proposed change, annotated with percent change reductions.

Life Cycle Assessment Impact Measures Tablecontinued

9 © KT INNOVATIONS

In this section, describe how you determined the baseline building for comparison. This description can be broken into three basic steps: describing the building, describing the functional equivalence between the baseline and proposed buildings, and describing the analysis scope and system boundary.

Describe the baseline building, beginning with an explanation of its equivalency with the proposed building in size, orientation, and function.In the first paragraph of the baseline building description, explain how you generated the baseline building, including how you determined the building type, square footage, orientation, and occupancy.

Describe the differences between the baseline building and proposed building.

Summarize the changes from the baseline building to make the proposed building in the following table, along with a description of how the change in design is retaining functional equivalence. The first line is provided as an example.

If you follow our best practices for creating a baseline building using Tally, use the Documentation Template text directly in your submission.

Description of Baseline Building

Confirm that the sample text in the Documentation Template reflects your scope of analysis, or edit the text as needed.

Description of change Explanation of equivalency in function and performance, including replacement ratesBaseline Proposed

PIR insulation Mineral Wool

insulation

Insulation assemblies were both designed to have an

R-value of 20 and to last the lifetime of the building

DOCUMENTATION INSTRUCTION

Include every change between the baseline and proposed building, including optimizations like dematerialization, concrete mix design, structural system selection, roofing membrane selection, facade detailing, etc.

Describe the building elements included in baseline building’s LCA.This paragraph should reflect which building elements were included in the Tally analysis. You should explain your analysis scope, as outlined in the Credit Overview section of this guide, and whether your analysis included interior finishes and partitions. It is important for you to identify which building elements are included and which are excluded from the analysis in order to confirm that your scope is consistent for the baseline and proposed buildings.

Include a list of all life cycle stages that were included in the baseline building’s LCA system boundary, as well as the assumed building service life.This paragraph should explain how the analysis for the baseline building uses the same lifespan and includes the same life cycle stages as the proposed building. Tally includes the full cradle-to-grave life cycle for materials, but it is up to you to input construction impacts, which are required for Option 4. Similarly, Tally has a default building life of 60 years, the recommended duration for this credit, but that number can be overridden, so you must verify the assumed building life span in your submission.

Confirm that the sample text in the Documentation Template reflects your LCA system boundary, or edit as needed.

10 © KT INNOVATIONS

In this part of the submission, summarize the design of the proposed building. You will describe the proposed building, as well as the analysis scope and system boundary of your LCA assessment. This description should be similar to the Description of the Baseline Building, because the purpose of the descriptions is to establish that the analysis scope and boundary are equivalent between the baseline and proposed buildings.

Begin with a description of the proposed project’s size, orientation and function.In this description include:

• Program• Number of residents• Square footage breakdown• General building form and orientation• Number of buildings (if submitting for LEED certification as a group)

Describe the building elements included in proposed building’s LCA.This text should be nearly identical to the description of the analysis scope for the baseline building in order to demonstrate that you performed a valid comparison between the baseline and proposed cases.

Include a list of all life cycle stages that were included in the proposed building’s LCA system boundary, as well as the assumed building service life.This text should be nearly identical to the description of the system boundary for the baseline building in order to demonstrate that you performed a valid comparison between the baseline and proposed cases.

Description of Proposed Building

DOCUMENTATION INSTRUCTION

Confirm that the sample text in the Documentation Template reflects your scope of analysis, or edit the text as needed.

Confirm that the sample text in the Documentation Template reflects your LCA system boundary, or edit as needed.

11 © KT INNOVATIONS

Upload a summary of the life cycle assessment tool.Include Tally Calculation Methodology in your submission, which provides a detailed explanation of Tally and identifies the assumptions built into the tool.

Upload the Tally Report Summary pages.Include the Report Summary pages from the baseline and proposed Tally reports for the whole-building LCA analysis, as shown in Figure 4.

Supporting Documents

Special Circumstances

DOCUMENTATION INSTRUCTION

Make a combined document including Tally Calculation Methodology and the baseline and proposed building Report Summary pages for this section.

In this part of the submission, describe any deviations from the credit submission guidelines or other extraordinary circumstances.

Describe circumstances specific to using Tally to perform your assesment.Tally reports environmental impacts in units that comply with TRACI 2.1. Tropospheric Ozone Formation (kg NOx or kg C2H4) is the impact category requested by the submission. This measure is slightly different from Smog Formation Potential (kg O3) which is reported by Tally. To address this, manually convert kg O3 into kg C2H4, or explain that you are submitting Smog Formation Potential impacts instead. The Documentation Template assumes that you will submit in units for Smog Formation Potential.

Include additional explanation as necessary.For example, you might need additional explanation if your project was altered during construction. In this case, provide a narrative of why the change durin construction should not affect the building’s LCA, or upload an additional Tally report to show definitively that the change does not affect the building’s LCA.

Review the sample text in the Documentation Template to include in your submission.

Figure 4. Snapshot of Report Summary page from Tally report.

12 © KT INNOVATIONS

Initiate an LCA workflow as the project begins.Distribute this guide to the team and meet early to anticipate moments where environmental impacts might be used to influence design decisions. Ask questions and plan to run targeted assessments of components and assemblies.

Relevant questions might include:

• What are the environmental trade-offs associated with the selection of structural system?

• How can we alter the concrete mixture composition to reduce environmental impacts?

• What are the environmental impacts associated with the façade design options?

Name and store Tally reports for documentation and future reference.As Tally reports are generated, record the date, the output names, and the question the report addresses in a tracking document. Also in this document, explain how the LCA analysis maintains equivalence between baseline and proposed conditions, and record the selected option as well as the other options considered. This tracking record will be essential to creating documentation for Option 4.

When comparing design options in Revit, model the baseline and proposed built conditions with the same functional unit. When comparing design options for the building envelope, ensure that the assemblies have equal surface area, duration, quality and maintenance using metrics like weather-tightness, fire-rating or U-value (functional equivalence). For example, when comparing two facade options, ensure that the surface area and R-value of the assembly is held constant (i.e. a 10’ x 10’ section of envelope with an R-value of 20).

Use this Tracking Spreadsheet to record questions and Tally assessments.

For detailed modelling guidance to meet EA Prerequisite Minimum Energy Performance, review the climate-specific guidelines within ASHRAE 90.1–2010, Appendix G, Opaque Assemblies, Vertical Fenestration, Skylights, and Roof Solar Reflectance and Thermal Emittance sections.

Best Practices

BEST PRACTICES

Now that you understand the requirements, here are a few best practices to effectively integrate Tally into your design workflow. By following these steps to track your use of Tally throughout the design process, you will be able to create a baseline building and prepare your submission documentation quickly and easily.

13 © KT INNOVATIONS

Perform a full-building LCA at the end of each design phase to see which materials are responsible for the bulk of the project’s footprint. This process can inform targeted LCA analysis and may reveal materials that warrant further investigation. If you do not have a full building at these stages, you can selectively model representative sections of the building, such as a structural bay or wall section, in order to get a sense of the overall impacts.

Generate a baseline building based on your proposed building model.At the end of the Construction Documents phase, generate a baseline building that reflects the initial design.

• Save a copy of your proposed Revit model.• Refer to the Tracking Spreadsheet to review alternative design options

considered during the design process.• Confirm that these alternative design options are functionally equivalent

to the proposed condition.• Use Tally definitions to update material assignments or remodel the

design options in Revit to reflect alternative design options.Include alternative materials or assemblies where the proposed design deviates from industry-standard materials. For example, if you increased the fly ash content in your concrete mix, alter your baseline to reflect the regional standard for fly-ash content in concrete.

Run Tally on the full building and the baseline building, limiting your analysis to the Option 4 scope. Calculate the percent change from the baseline building’s values to the proposed building’s values for each of the six relevant impact categories using the formula:

This can be accomplished in Tally by using a design option report, if both final and baseline buildings are contained in the same model, or by generating Tally reports individually and comparing the total results in a spreadsheet.

BEST PRACTICES

Common contributors to building footprint:

• structural system• concrete-mix• roofing membrane• insulation type

continuedBest Practices

Baseline Building Value - Proposed Building Value

Baseline Building Value

14 © KT INNOVATIONSRESOURCES

Want to learn more about Tally or Life Cycle Assessment? Webinars, tutorials, an LCA glossary, and more can be found on the Tally website at www.choosetally.com.

Need more help? Reach out to the LCA experts at KT Innovations by emailing support@choosetally.com.

If you have feedback on Tally or this guide, we’d love to hear from you.

Resources