The following settings are applied at project-level, meaning they are applied to the baseline and all scenarios within the project. This is done so that all scenarios, including the baseline, have the same underlying assumptions, and thus, can be comparable.

To refine the project, click All Project Settings in the left-hand panel.

Scope

One of the leading causes of misalignment between wbLCA results is that they cover different project scopes. For instance, one model may contain only "structure, foundation, and envelope" while another will contain "structure, foundation, envelope, interiors, MEP, and site."

C.Scale allows project teams to refine the scope of analysis by including or excluding LCA stages or parts of the building to meet reporting goals or to facilitate comparison with other projects.

Any decarbonization measures in excluded parts of the project scope are still saved with the project, but will become temporarily unavailable as long as they are out of scope. When their scope is restored, the values will reappear as last entered.

Analysis Period

Select an analysis period to determine over how many years the analysis takes place.

Life Cycle Stages

A4-A5 (Construction Process) Turning off this toggle will remove construction process emissions—counted in the A4 and A5 life cycle stages—from the C.Scale model. This toggle will enable and disable the "Jobsite" decarbonization measures in the right-hand panel.

D, Biogenic Carbon Storage, and Avoided Emissions Turning off this toggle will remove biogenic carbon stored in timber structural elements, carbon sequestered in landscape, and emissions avoided by excess energy production from on-site renewable from the C.Scale model.

Scope Categories

Structure Structure and Foundations are always included.

Enclosure Turning off this toggle will remove the embodied carbon associated with cladding, glazing, and roofing from the C.Scale model, and disable the "Enclosure" decarbonization measures in the right-hand panel.

Interior Turning off this toggle will remove the embodied carbon associated with interior fitouts from the C.Scale model, and disable the "Interior" decarbonization measures in the right-hand panel.

Services Turning off this toggle will remove the embodied carbon associated with MEP and PV Arrays (the energy generated by PV panels will still be included), and disable the "Services" decarbonization measures in the right-hand panel.

Refrigerants Turning off this toggle will remove the emissions associated with refrigerant use in the building, and disable the "Refrigerants" decarbonization measures in the right-hand panel.

Sitework Turning off this toggle will remove all site and landscaping from the C.Scale model, and disable the "Sitework" decarbonization measures in the right-hand panel.

General

Unit System

Modify the unit system for the project's calculations.

Project Name

Select a name for your project.

Project Location

Year of Project Completion

The year that construction is completed and building operation begins. This is the year to which construction emissions are attributed and the C.Scale model begins calculating operational carbon emissions.

Location

Country

The country in which the project is located. Note: a project's country cannot be modified after creating a project.

Postal Code

The postal code in which the project is located.

Use

Primary Use

The use category from the list below most reflective of the project’s main use. This is used to determine the building's energy use and its structural requirements.

Secondary Use

If the primary use comprises less than 100% of the program, a secondary program may be selected for the remainder. This program will affect the EUI (resulting in a ‘blended EUI’) but will not affect the estimate of the building’s structural system.

Building Size

Number of Above Ground Floors

The number of building floors above grade. These floors will be assessed using the selected structural system.

Total Above Ground Constructed Floor Area

The total constructed floor area above ground.

Number of Below Ground Floors

The number of building floors below grade. These floors will be assessed as having a reinforced concrete structural system.

Total Below Ground Constructed Floor Area

The total constructed floor area below ground.

Sitework

Total Site Area

The total site area, including the building footprint and landscaping. The site area cannot be smaller than the building's footprint.

Previously Developed (Brownfield) Site

If the site is not previously developed, it is a greenfield site and the project incurs an emissions penalty for the site disturbance. The magnitude of this penalty is equivalent to the site area’s sequestration potential with low-sequestration plantings.

Electricity Grid

Future Scenario

The future of the electric grid is uncertain. C.Scale gives the user the choice between three future scenarios, each derived from NREL's CAMBIUM model.

• Expected decarbonization. Average estimates for inputs such as technology costs, fuel prices, and demand growth. No inclusion of nascent technologies. Electric sector policies as they existed in September 2022, with the assumption that the Inflation Reduction Act’s Production and Investment Tax Credits do not phase out. This metric is described in NREL's Cambium model as "Midcase."

• Slow Decarbonization. Average estimates as in the mid-case scenario, but with an assumption that battery and renewable energy costs are high. This scenario assumes that the thresholds set by the Inflation Reduction Act’s Production and Investment Tax Credits are not met and, as such, they do not phase out. This metric is described in NREL's Cambium model as "High Cost of Renewable Energy."

• Rapid Decarbonization. Average estimates for inputs such as technology costs, fuel prices, and demand growth. Nascent technologies are included. Electric sector policies as they existed in September 2022, with the assumption that the Inflation Reduction Act’s Production and Investment Tax Credits do not phase out. High-level assumption that the national electricity grid's carbon emissions in 2050 are 5% of their 2005 level. This metric is described in NREL's Cambium model as "95% decarbonization by 2050."

Emission Metric

For a given scenario, there are multiple methods to account for the emissions associated with a building. Two metrics are provided in C.Scale, both derived from NREL's CAMBIUM model. Both metrics use GWP-100 characterization factors.

• Average Emission Rate (AER). By default, C.Scale measures annual emission factors by summing the total generation of all resources in a given year and putting them on a MWh basis. This average emission rate also includes 'precombustion emissions from the leakage of fossil gas in the energy supply chain. This metric is described in NREL's Cambium model as "AER Load: Combustion + Precombustion."

• Long-Run Marginal Emission Rates (LRMER). LRMER emissions are described by NREL as emission rates for “of the next unit of electricity considering the grid’s structure as variable.” This emission metric is preferable to a simple average emission rate because buildings are long-lived assets whose demand for energy has a marginal influence on the evolution of the energy grid. This metric is described in NREL's Cambium model as "LRMER: Combustion + Precombustion."

Refrigerants

Average Refrigerant Leakage Rates

Annual and end-of-life refrigerant leakage rates are typically a model assumption, not a carbon reduction measures. In c.scale, there are two options for leakage assumptions.

Basic Workflow

In C.Scale, the basic workflow is:

1. Create a Project

2. Set a Baseline

3. Reduce Emissions

4. Compare Scenarios

5. Create a Portfolio [Organization feature]

6. Compare Projects within Portfolio [Organization feature]

Important definitions

• A Project includes a baseline and one or more decarbonization scenarios.

• A Baseline is a scenario for a project where no attempts have been made to reduce carbon emissions. To define a baseline, C.Scale makes a set of "business as usual" assumptions based on user inputs. When C.Scale's "business as usual" assumptions are not appropriate, they can be refined.

• A Scenario is a set of strategies to lower a project's carbon emissions. Scenarios are constructed individually and compared against one another in the Compare Scenarios tab.

• A Portfolio includes all active projects in your organization, allowing for an "apples to apples" comparison across the same scope categories and LCA stages.

The C.Scale data model

The C.Scale app is powered by the C.Scale data model.

Get in touch!

If you'd like to offer feedback on C.Scale or the documentation, please get in touch.

C.Scale is a whole life carbon tool supporting climate-positive design decisions across the building design and delivery life cycle, especially in early project phases when data is scarce but the potential for emissions reduction is high. To overcome the scarcity of data, C.Scale uses a model that combines regionally-specific background data, forward-looking projections, peer-reviewed findings, and industry-leading ML models to assess the relative impact of a variety of carbon reduction measures on a project’s embodied, operational, and landscape carbon footprints.

Aggressive time-based targets have been set for the built environment as part of a society-wide strategy to combat the climate crisis. To meet these targets, quantification of the project’s whole life carbon footprint cannot wait until later project stages, at which point many impactful decisions have already been made. C.Scale is designed as the first step in an iterative low-carbon design process, setting out strategies and project-level targets that can be refined throughout the project lifecycle.

C.Scale is useful to project teams:

• in setting a whole life carbon budget for a project.

• to evaluate the most impactful strategies for reducing whole life carbon emissions at the very beginning of a project, when data is scarce but the potential for reducing emissions is high.

• to roughly approximate whole life carbon emissions from a project when completing an energy model and a wbLCA is not practical.

• to compare approximate whole life carbon emissions across projects in your entire portfolio. [Organization feature]

C.Scale is designed to allow a user to enter a strict minimum of project parameters and to test a wide range of the most meaningful carbon reduction strategies. These parameters are insufficient, of course, to describe the complexity of any real project. In rough terms, C.Scale is designed as a conceptual parallel to ‘shoebox’ energy or daylight models—the results do not correspond directly to a specific building but can help us to understand which strategies could perform well, are unlikely to succeed, or are worthy of more attention.

C.Scale is not a high-resolution wbLCA tool.

C.Scale is designed to accurately represent the overall effects of decarbonization strategies, not precisely model individual design parameters or perform ISO-compliant LCA. C.Scale can help your team compare a net zero energy retrofit with mass timber new construction, for instance, but is not designed to capture differences in, say, efficiency gains from changing structural bay sizes or specifying one brand of heat pump versus another.

C.Scale is not a fortune teller.

If we could predict the future with 100% accuracy, we'd be in another line of work. C.Scale contains estimates of future emissions, but the future is inherently uncertain. In 2021, for instance, the last version of our data models did not predict the passage of the IRA or the continued operation of California's Diablo Canyon Nuclear Power Plant—two events which have since come to pass and have significantly affected our estimates of electricity-related emissions from buildings. As a corollary, we are not in the business of predicting which low-carbon concrete technology will achieve the greatest market share, which timber supply chain will be most disrupted by climate change, and so on. To the extent that trusted data sources make these predictions, we follow their lead. Documentation of these data sources in the documentation for the underlying C.Scale data model.

A project is where the baseline and scenarios can be modeled, analyzed, and compared to each other.

From the dashboard, begin by clicking the + New Project button.

Fill in the required information and click Create.

After creating your project, many more project settings can be configured by clicking All Project Settings in the left-hand panel of the project page.

To determine a decarbonization target for the project, carbon reduction measures can be applied to scenarios. C.Scale highlights salient carbon reduction measures that can be consistently modeled with available data. The set of carbon reduction measures included in C.Scale do not represent an exhaustive list of possible emission reduction strategies.

Reuse

Building Reuse

The percentage of existing building materials to remain on-site and be used in the project, reducing the demand for new materials.

Form and Massing

Building Perimeter

The user-declared perimeter of the building. In the absence of a user input, C.Scale assumes the building is an extruded square.

Floor-to-Floor Height

The vertical distance between building floors in feet. The default value is 13’.

Window-to-Wall Ratio (WWR)

The ratio of windows to total wall area. The default value is .45.

Energy Use

All Electric Building

The elimination of all onsite combustion and provision of 100% of the project’s energy use from electric sources.

EUI Target

The reduction of the building’s EUI by any of a number of strategies. If the you have not entered a custom EUI, the EUI is estimated via ZeroTool.

Clean Power Purchase

The purchase of clean power through Direct Ownership, Green Retail Tariffs, Power Purchase Agreements (PPAs), Community Renewables or Utility Renewable Contracts (the five categories of renewables for which credit can be claimed in AIA 2030 commitment reporting) equivalent to the selected percentage of total energy use. The purchase of unbundled RECs should not be counted as a clean power purchase in C.Scale.

Solar Photovoltaic (PV) Array System Design

The addition of a solar PV array on the project site. The size of this array can be input in three forms:

• Percentage of Load. The solar PV area size is calculated to account for the input percentage of building energy load.

• Nameplate Capacity. The solar PV area size is input by its nameplate capacity in kW.

• Area. The solar PV area size is input by its total area in square feet.

Solar PV orientation

The ability of solar PV arrays to produce electricity is related to their geometry and siting. Not all projects sites, such as partially shaded sites, will have an optimal solar orientation. This toggle has two options:

• Optimal. There is no impediment on the site to maximum solar exposure.

• Suboptimal. There is solar potential on the site, but it is partly compromised. A 20% penalty on solar energy production will be assessed.

Structure

Primary Structural System

Specification of a structural system other than the system modeled in the baseline. Note that this is not strictly a carbon reduction measure, as the substitution of some structural systems with some others can lead to an increase in embodied emissions.

Secondary Structural System

Specification of a secondary structural system, and its associated percentage of the overall building structure.

Concrete Specification

The specification of concrete with lower embodied carbon emissions. Choices are described in narrative form below, and the underlying data is listed in C.Scale's whole life carbon methodology. Narrative descriptions are approximate; there are many options that can yield similar carbon intensities.

Steel Specification

The specification of structural steel, steel deck, and reinforcing bar with lower embodied carbon emissions. Choices are described in narrative form below, and the underlying data is described in C.Scale's whole life carbon methodology. Narrative descriptions are approximate; there are many options that can yield similar carbon intensities.

Timber Specification

The specification of lumber, plywood/OSB, and engineered timber elements with lower embodied carbon emissions. Choices are described in narrative form below. Narrative descriptions are approximate; there are many options that can yield similar carbon intensities.

Responsibly-Sourced Timber

In accordance with ISO 21930, the carbon content of biogenic materials can only be counted as carbon-storing if the timber comes from a forest managed with sustainable practices. An example of this is timber from an FSC-certified forest. For more information, please refer to C.Scale methodology for stored and avoided carbon emissions or the procurement guidance from the Climate Smart Wood Group.

In C.Scale, we identify three criteria contributing to the claim that wood products are responsibly sourced. While C.Scale does not prevent the user from counting the carbon storage benefits on other terms (as the list is nonexhaustive), we recommend meeting at least two out of the three criteria below in order to claim climate benefits from carbon storage.

Enclosure

Opaque Enclosure Specification

The specification of the opaque envelope assemblies. These specification levels do not describe specific assemblies. Instead, they approximate the 80th, 50th, and 20th percentile of the distribution of all opaque enclosure options.

Opaque Enclosure Refresh Rate

The length of time over which a majority of the opaque enclosure will be replaced.

Transparent Enclosure Specification

The specification of the transparent enclosure assemblies. These specification levels do not describe specific assemblies. Instead, they approximate the 80th, 50th, and 20th percentile of the distribution of all transparent enclosure options.

Transparent Enclosure Refresh Rate

The length of time over which a majority of the transparent enclosure will be replaced.

Roofing Specification

The specification of the roofing assemblies. These specification levels do not describe specific assemblies. Instead, they approximate the 80th, 50th, and 20th percentile of the distribution of all roofing options.

Roofing Refresh Rate

The length of time over which a majority of the roofing will be replaced.

Interior

Floor Area w/ Fit-Out

The percentage of floor space that will be fitted out for occupation by building tenants. The default value is 70%. If tenant fit-out is outside the project scope, this field can be set to 0%.

Interior Fit Out Specification

The specification of the fittings, furniture, and fixtures required for the use of the building by its tenants. These specification levels do not describe specific fit-outs or materials. Instead, they approximate the 80th, 50th, and 20th percentile of the distribution of all available data on tenant fit-outs.

Interior Fit-Out Refresh Rate

The length of time over which a majority of the interior fit out will be replaced.

Services

Conditioned Area

The percentage of total floor area that is heated or cooled.

MEP Specification

Embodied carbon in mechanical systems in evaluated at two specification levels—standard performance and high performance—and is dependent of the total square footage of the building. This approach, and the data used in C.Scale, follow from the CLF study on building mechanical systems.

Baseline buildings in C.Scale are always assumed to have a standard performance system. Scenarios that achieve an EUI reduction of more than 50% below the baseline are assumed to have a high performance system.

Embodied carbon in MEP is a data-scarce category, and we cannot confidently describe the potential to reduce embodied carbon in MEP systems through specification.

MEP Refresh Rate

The length of time over which a majority of the MEP systems will be replaced.

PV Specification

Embodied carbon in solar photovoltaics arrays is calculated using values from the peer-reviewed literature. A citation to the current data source is available in in the Reference Data Sources section of this guide.

PV Refresh Rate

The length of time over which a majority of the PV systems will be replaced.

Solar ground coverage ratio

For any solar array entered as a decarbonization measure, this ratio describes the ratio of active solar cells to total array area. C.Scale's assumption is 0.7, representing an efficient solar layout.

Refrigerants

Total Refrigerant Charge

The reduction of the total quantity of refrigerants used in the buildings HVAC+R system.

Refrigerant GWP

The average global warming potential (GWP) of refrigerants used in the buildings HVAC+R system.

Sitework

Planted Area

Set the percentage of site area, minus the building footprint, which is planted. This planted area is assumed to be a low carbon storage landscape, such as no-mow turfgrass or other herbaceous perennials. All unplanted area is assumed to be hardscape.

High Carbon Storage Planted Area

Set the percentage of the planted site area comprised of a high carbon storage landscape, such as dense broadleaf shrubs and trees in a matrix of no-mow turfgrass or herbaceous perennials.

Hardscape specification

The specification of the pervious and impervious surfaces on the building site (outside the building envelope. These specification levels do not describe specific materials or assemblies. Instead, they approximate the 80th, 50th, and 20th percentile of the distribution of all hardscape assemblies based on a set of standard details.

Hardscape Refresh Rate

The length of time over which a majority of the site's hardscape will be replaced.

Jobsite

A5.2 Jobsite Emissions

Enter a custom carbon intensity (kgCO₂e/sf) for jobsite emissions related to construction activities and land use. The default value assumes 40 kgCO₂e/m² for construction emissions, which includes fuel, tools, and energy used on-site. This default is adjustable based on project-specific data. For greenfield sites, emissions from soil and vegetation are also calculated, using regional data to estimate carbon release from land development.

Demolished Area

Pre-construction demolition emissions are calculated per floor area of the demolished building, using a default factor of 35 kgCO2e/m2. This is a data-scarce category. Where project-specific data is available, this default can be overridden by the user.

A scenario can be set as target by clicking the 3-dot menu to the right of the scenario name in the left-hand panel.

Within the menu, click Set as Target.

The C.Scale Organization Account offers a range of powerful features to enhance your firm's workflow in whole life carbon analysis. Here are the key benefits of using the Organization Account:

1. Start for Free: Start using the Organization Account at no cost for up to three projects, allowing you to explore the available features.

2. Seamless Project Transfer: Once you're satisfied with your project in your Personal Account, easily transfer it to the Organization Account for enhanced capabilities.

3. Sharing and Collaboration: All users within your organization can view and edit projects, promoting efficient collaboration across teams. See detailed information about who last updated a project or scenario, ensuring better transparency and accountability.

4. Chart Exports: Download all graphic charts in C.Scale in both PDF and transparent PNG formats for easy use in your presentations.

5. Comprehensive AIA 2030 DDx Reports:

   1. Download individual project reports in PDF format for thorough documentation.

   2. Export multiple projects at once in bulk as an Excel file for easier analysis.

6. Portfolio-Wide Project Comparison: Create tailored static and dynamic portfolios to suit your specific needs. Effortlessly compare chosen projects across your entire portfolio, gaining valuable insights to drive strategic decision-making and optimize your results.

...and many more to come very soon!

Interested in a free trial of our Organization Account? Click here to get started!

Ready to scale your impact? Sign up for an Unlimited Organization Account here and unlock all the benefits!

Rename a Scenario

A scenario can be renamed by clicking the 3-dot menu to the right of the scenario name in the left-hand panel.

Within the menu, click Rename.

Modify the scenario's name and click Save.

Duplicate a Scenario

A scenario can be duplicated by clicking the 3-dot menu to the right of the scenario name in the left-hand panel. This creates a new scenario with the same set of carbon reduction measures as the original scenario. This option is useful when constructing a sequence of carbon reduction strategies where each builds on the last.

Within the menu, click Duplicate.

A duplicated version of the selected scenario will be created with "(copy)" at the end of its name.

Delete a Scenario

A scenario can be deleted by clicking the 3-dot menu to the right of the scenario name in the left-hand panel.

Within the menu, click Delete.

Confirm you would like to delete the scenario by clicking Delete.

Sharing and collaboration is available in the shared Organization Account. To collaborate on projects in your personal account, you must first move them to the shared organization account. To do so, click on the 3-dot menu to the right of the project name. Choose the Move option.

A pop-up window opens up, choose your Organization from the drop-down menu and click Move.

To switch to the Organization Account, click on the drop-down menu in the top-left corner of your screen where it currently says "Personal Account." From there, select the organization name (in this case, C.Scale).

Awesome! You’re now on the Organization Dashboard. Here, you can view all the projects your organization is working on in real-time.

Click on any project to see who in your organization has worked on it and made updates. In the left-hand panel, you’ll find a history showing when the project was last edited and by whom.

To see information about who updated individual scenarios within projects, simply hover over the scenario name.

Scenarios can be analyzed using the following charts found within the This Scenario tab.

Emissions Over Time

This figure describes the cumulative carbon emissions of a building over time. As a chart of cumulative emissions, the height of the bar in each year is the total emissions associated with the building up to and including that year rather than only the emissions associated with that year.

This chart has a number of elements:

• Reduction from Baseline. Cumulative reduction in emissions of the current scenario as compared to the baseline.

• Refrigerant Emissions. Cumulative emissions associated with the refrigerant use in the building services.

• Electricity Emissions. Cumulative emissions associated with the energy use from the electrical grid.

• Fossil Fuel Emissions. Cumulative emissions associated with onsite fossil fuel use.

• Embodied carbon emissions. Cumulative emissions associated with building materials, their replacements, and with landscape maintenance.

• Biogenic Carbon Storage. Sequestered emissions from building structure and landscape planting.

• Avoided Energy Emissions. Avoided emissions from onsite energy generation in excess of use.

• Net Emissions. Operational, embodied, and refrigerant emissions minus biogenic carbon storage and and avoided energy emissions.

• Climate Positive Threshold. When the net emissions of a project crosses the zero line, the crossing point is marked as the Climate Positive threshold.

Hovering over a bar gives the summary of emissions in that year. This is useful for determining how the project is performing against time-based targets (e.g. a 2030 net zero target). Hovering over the final year in the chart gives the total emissions across the analysis period. Note that these numbers are rounded to the nearest hundred and may not sum to net emissions in all cases.

Emissions by Scope Category

This chart breaks down the building's contribution to operational carbon emissions (B6), embodied carbon emissions (A1-A3, A4-A5, B1, B2-B5, C1-C4, D), and biogenic carbon storage by scope category. This figure represents the total cumulative emissions associated with the scenario across the entire analysis period.

When comparing C.Scale results to wbLCA results at later project phases, this breakdown can be helpful in confirming if designs are within the carbon budget for a particular scope cateory for the project as a whole.

Each of the scope categories breaks carbon emissions into the following Life Cycle Stages:

• A1-A3. Total upstream product emissions associated with the scope category.

• A4-A5. Total construction jobsite emissions associated with the scope category.

• B1. Total in-use emissions associated with the scope category.

• B2-B5. Total replacement and refurbishment emissions associated with the scope category.

• B6. Total energy use emissions associated with the scope category.

• C1-C4. Total end-of-life emissions associated with the scope category.

• D. Total benefits beyond the system boundary (typically from recycling materials) associated with the scope category.

• Biogenic Carbon Storage. Total carbon stored by biological materials.

Emissions by Life Cycle Stage

This chart breaks down the building's contribution to operational carbon emissions (B6), embodied carbon emissions (A1-A3, A4-A5, B1, B2-B5, C1-C4, D), and biogenic carbon storage by LCA stage. This figure represents the total cumulative emissions associated with the scenario across the entire analysis period.

When comparing C.Scale results to wbLCA results at later project phases, this breakdown can be helpful in confirming if designs are within the carbon budget for a particular LCA stage for the project as a whole.

Each of the LCA stages breaks carbon emissions into the following scope categories:

• Energy Use. Sources and use of energy in the building.

• Structure. Substructure and superstructure, including both lateral and gravity systems.

• Enclosure. Opaque enclosure, transparent enclosure, and roofing.

• Interior. Interior construction and fit-out.

• Services. Mechanical, electrical, and plumbing (MEP) services and PV Array.

• Refrigerants. Refrigerants used in building services (e.g., HVAC+R).

• Sitework. Hardscape and landscape surrounding the building.

• Jobsite. Construction-related processes.

• Biogenic Carbon Storage. Total carbon stored by biological materials.

Emissions Summary

This donut chart displays the proportional relationship of the scenario's emissions over the analysis period.

This chart has a number of elements:

• Refrigerant Emissions. Cumulative emissions associated with the refrigerant use in the building services.

• Electricity Emissions. Cumulative emissions associated with the energy use from the electrical grid.

• Fossil Fuel Emissions. Cumulative emissions associated with onsite fossil fuel use.

• Embodied carbon emissions. Cumulative emissions associated with building materials, their replacements, and with landscape maintenance.

• Biogenic Carbon Storage. Sequestered emissions from building structure and landscape planting.

• Avoided Energy Emissions. Avoided emissions from onsite energy generation in excess of use.

• Net Emissions. Operational, embodied, and refrigerant emissions minus biogenic carbon storage and and avoided energy emissions.

• Reduction from Baseline. Cumulative reduction in emissions of the current scenario as compared to the baseline.

• Energy Use Intensity (EUI). Energy use by the building per area per year.

• Embodied Carbon Intensity (ECI). Embodied carbon emissions from the building over the analysis period divided by the building area.

Create a new scenario

Scenarios are user-defined sets of carbon reduction measures that can be analyzed and compared with one another.

Click the + New Scenario button to create a new scenario where carbon reduction measures can be applied. The newly created scenario will include all of the carbon reduction measures that are applied to the baseline. Additionally, existing scenarios can be duplicated to create new scenarios.

Name the new scenario and click Create.

With the newly created scenario selected in the left-hand panel, use the right-hand panel to begin applying carbon reduction measures, which are generally divided into the following categories:

• Reuse. These measures deal with the savings from reuse of existing building assemblies.

• Form and Massing. These measures pertain to the impact the form of the building has on the amount of materials used in the structure and enclosure.

• Energy Use. These measures pertain to reducing the use of energy in the building, and selecting clean sources of energy.

• Structure. These measures pertain to selecting low carbon alternatives for the substructure and superstructure, including both lateral and gravity systems.

• Enclosure. These measures pertain to selecting low carbon alternatives for the opaque enclosure, transparent enclosure, and roofing, and their replacement periods.

• Interior. These measures pertain to selecting low carbon alternatives for the interior construction and fit-out, and their replacement periods.

• Services. These measures pertain to selecting low carbon alternatives for the mechanical, electrical, and plumbing (MEP) services and PV Array, and their replacement periods.

• Refrigerants. These measures pertain to selecting low carbon alternatives for the refrigerants used in building services (e.g., HVAC+R).

• Sitework. These measures pertain to the hardscape and landscape surrounding the building, and assess their respective potential to add or sequester carbon.

• Jobsite. These measures pertain to the construction-related (A5) emissions.

A Portfolio lets you compare all active projects in your organization across the same scope categories and LCA stages, ensuring consistency and normalization for an "apples to apples" comparison.

From the Organization Dashboard, begin by clicking the + New Portfolio button.

Portfolios can be created to be either Static or Dynamic.

1. Static Portfolios:

You can manually add projects to create a Static Portfolio.

Projects can be added once to create a Static Portfolio.

Fill in the required information and click Create.

1. Dynamic Portfolios:

Dynamic portfolios can be created by using filters for Primary Use Case.

Select the Primary Use Case, and the app will automatically add all the Projects in your Organization to the Portfolio. C.Scale will also automatically include any new projects with the same Primary Use Case into the Dynamic Portfolio.

Fill in the required information and click Create.

After creation, click on the desired Portfolio Name to open up the portfolio view.

Note: All projects within the Portfolio are compared based on the target scenarios set within the project.

Exporting graphics was a highly requested feature! To get started, click the Download button located on the right side of all the charts available on C.Scale.

From the drop-down, choose to download the chart in either PNG or PDF format.

The PNG is downloaded with a transparent format so it can be added to your presentations. Below is an example of how it will look.

To create AIA DDx reports, make sure to set the Target Scenario for all the projects you want to include in the report.

AIA DDx Reporting can be done in two ways within the C.Scale app:

1. Individual project reporting:

Inside the project, right above the Project Name, you'll find an Export button. Click on it and select the AIA 2030 Commitment Embodied Carbon Report (PDF).

A pop-up menu opens up where you can choose the Phase of Project and Export.

The PDF report is designed to mirror the AIA DDx Reporting interface, making it easy for you to report. Just copy the content from the boxes and paste it directly into the Reporting interface! Easy, peasy!

1. Bulk reporting:

To bulk report multiple projects, go to the Organization Dashboard and click on the Export button located at the top-right of the projects table. From the drop-down, choose AIA 2030 DDx Bulk Export.

A pop-up menu will appear, displaying all the projects your organization is working on. You can either select All Projects or choose individual projects one by one that you want to report on. Once you've made your selection, click the Export button to proceed.

The exported Excel file contains all the essential information you need for reporting to the AIA 2030 Commitment. Below is an example of what the file may look like.

Total Emissions Over 60 Years

This figure describes the cumulative carbon emissions of a building over time. As a chart of cumulative emissions, the height of the bar is the total emissions associated with the building up to and including that year rather than only the emissions associated with that year.

This chart has a number of elements:

• Choice of overall units. Choose to view the emissions in kgCO₂e/m² or tCO₂e.

• Refrigerant Emissions. Cumulative emissions associated with the refrigerant use in the building services.

• Electricity Emissions. Cumulative emissions associated with the energy use from the electrical grid.

• Fossil Fuel Emissions. Cumulative emissions associated with onsite fossil fuel use.

• Embodied carbon emissions. Cumulative emissions associated with building materials, their replacements, and with landscape maintenance.

• Biogenic Carbon Storage. Sequestered emissions from building structure and landscape planting.

• Avoided Energy Emissions. Avoided emissions from onsite energy generation in excess of use.

Hovering over a bar gives the summary of emissions of that project. Note that these numbers are rounded to the nearest hundred and may not sum to net emissions in all cases.

C.Scale assesses the efficacy of carbon reduction measures in relative terms as a reduction in the carbon emissions from a baseline scenario. The baseline scenario is determined from a set of conservative assumptions which represent a project in which no efforts have been made to reduce carbon emissions. The baseline scenario provides a means of comparison for evaluating carbon reduction measures.

• Baseline scenarios are fully customizable.

• Baseline scenarios can be configured as new construction, renovation or a combination of both.

• Baseline scenarios can be configured to align with code.

• Baseline scenarios are flexible, and any scenario can be tagged as the baseline.

Refining the Baseline

In the left-hand panel, select the scenario tagged "Baseline".

After selecting the baseline scenario in the left-hand panel, the following warning will be displayed in the right-hand panel. The warning serves as a reminder that you are editing the baseline, which is used as the reference for all other scenarios.

The baseline can be refined using the Carbon Reduction Measures in the right-hand panel.

Setting Another Scenario as the Baseline

Any scenario within the project can be set as the baseline, and serve as the reference point for the project. To set another scenario as the baseline, click the 3-dot menu to the right of the scenario name in the left-hand panel.

Within the menu, click Set as Baseline to set another scenario as the reference for comparison.

Analyzing the Baseline

With the baseline scenario selected in the left-hand panel, it can be analyzed using the following charts:

• Emissions Over Time

• Emissions by Scope Category

• Emissions by Life Cycle Stage

• Emissions Summary

Welcome to C.Scale!

C.Scale is a whole life carbon calculation engine estimating emissions from the construction, renovation, and operation of buildings. When highly-detailed energy modeling and life cycle assessment aren't affordable or practicable, teams use C.Scale.

C.Scale is designed for use during site and feasibility studies, requests for proposals, pre-design, in retrospective analysis, or in other situations where a whole-building life cycle assessments and/or energy models are not practicable.

The model allows a user to enter a strict minimum of project parameters to test a wide range of the most meaningful carbon reductions strategies. It is the calculation engine behind numerous web applications and research efforts focused on both forward-looking planning and retrospective analysis of carbon emissions from buildings and the built environment.

We ship features continuously, and have an exciting roadmap for the year ahead. Features are developed in response to user feedback, to incorporate improved data, and to refine the tool's methodology. Something you'd like to see? Reach out.

C.Scale calculates whole life carbon emissions

C.Scale integrates embodied, operational, and landscape carbon emission assessment into a single model. By taking a 'whole carbon' view, C.Scale prevents burden shifting and ensures that a project team has the information necessary to target the most impactful carbon reductions.

C.Scale uses GWP-100 characterization factors.

C.Scale describes typical buildings

Every attempt has been made to ensure that C.Scale's results describe a typical building (i.e. a building similar to those in our database) whose characteristics match those you enter in the tool. However, unreported characteristics may make a particular building atypical in ways that it is beyond the scope of C.Scale to describe.

For instance, the use of particularly high-carbon and high-cost finish materials (e.g., a building where all the millwork is in gold leaf) is not well-described by C.Scale. It is impossible to preemptively describe all cases where C.Scale might deviate from a particular building (the possibilities are literally endless) but, as your project progresses, we recommend that your project team remains aware of how any deviation from "typical" design will affect the project's climate goals.

C.Scale is a time series model

In the built environment, it is essential to understand the time value of carbon. To this end, C.Scale uses time series data to analyze carbon emissions across a building's life. For each year in the analysis period (defined by the project's time horizon), C.Scale estimates all emissions occurring in that year.

In the first year, the following emissions are always calculated:

• Embodied emissions in construction materials (life cycle stages A1-A3)

• Construction site emissions (life cycle stages A4-A5)

• Storage of biogenic carbon in timber structural components (life cycle stage D)

In each year, the following emissions are always calculated:

• Operational carbon emissions from onsite fossil fuel use (life cycle stage B6)

• Operational carbon emissions from onsite electricity use (life cycle stage B6)

• Emissions from landscape maintenance, when applicable (life cycle stage B2)

In only some years, the following emissions are always calculated:

• Replacement and refurbishment of hardscape (life cycle stages B3-B5)

• Replacement and refurbishment of the building envelope (life cycle stages B3-B5)

• Replacement and refurbishment of interior fit-out (life cycle stages B3-B5)

• Replacement and refurbishment of MEP and PV systems (life cycle stages B3-B5)

Building Geometry in C.Scale

C.Scale's calculations are based on area and material takeoffs from simple building geometry. A diagram of this building geometry is provided below.

C.Scale is customizable and extensible

C.Scale is built as a series of modules, each connected to the others and tasked with a specific set of calculations. These modules are added or expanded in response to the requests of users.

The C.scale model's assumptions and background data can be overriden or refined through additional inputs. This allows for the addition of project-specific data where it is available while maintaining the C.Scale model for calculating all other parts of the project's carbon footprint. For more information on how this works, check out our Swagger docs or reach out for a conversation.

Goal

C.Scale provides directionally accurate guidance for specific projects by helping to identify which carbon reduction strategies a project should pursue, and helps to guide decarbonization of portfolios and portions of the building stock where C.Scale assumptions have been tested (i.e., in North America and the EU).

Scope

C.Scale is an whole life carbon model, integrating assessments of embodied, operational, and landscape carbon in a data model to capture the entire carbon footprint of the project.

By default, all emissions associated with the building are included in the model's scope of analysis.

Geographic Coverage

In countries where our users are based, we use country-level data. Additional countries are added regularly, usually in response to user requests.

Where country-level data is not available, we use generic regional background data. Background data sets currently include:

• North America (NAM)

• Europe (EU)

• Rest of World (RoW)

Time Horizon

C.Scale is a time series model and can calculate emissions over a time horizon of either 30 or 60 years. Support for additional time horizons is under development.

Reference Service Life

C.Scale assumes a building's reference service life of 60 years.

Life Cycle Stages

C.Scale integrates data from life cycle stages (sometimes called "life cycle modules") A1-A5, B2-B6, and C2-C4. These correspond to the impacts of the materials used in the project, emissions from construction, their replacement over time, and the project’s operational energy use. When biogenic carbon is counted, some end-of-life impacts (from modules C2-C4) are assessed during the product phase (see section on Biogenic Carbon). End-of-life (C2-C4) emissions for structure are only assessed when a 60 year time horizon is selected.

C.Scale also includes a model of fugitive refrigerant emissions (B1) and of benefits from the export of renewable energy to the utility (D2).

Embodied Carbon Scope

C.Scale includes an assessment of embodied carbon from the following sources:

• Building structure and foundation

• Construction activities

• Cladding, glazing, and roofing assemblies and their replacement over time

• Interior fit-outs and their replacement over time

• MEP systems and their replacement over time

• PV arrays and their replacement over time

• Regular landscape maintenance, assessed annually

• Hardscape on the building site

Operational Carbon Scope

C.Scale considers operational emissions from the following sources:

• Emissions from the combustion of methane gas in the building

• Upstream leakage of methane gas as a proportion of methane gas combusted in the building

• Upstream emissions from the generation of electricity delivered to the site

• Refrigerant leakage annually and at the end of the equipment's life.

Stored Carbon Scope

C.Scale includes an estimate of carbon storage in timber structural systems and site landscaping. Carbon storage in planting is calculated over the time horizon then annualized. Carbon storage in building structure is assigned to the first year of the project. C.Scale's method for calculating carbon storage in timber structural systems is detailed in the section on stored and avoided carbon.

Adjusting the Analysis Scope

In C.Scale, you can add or remove some life cycle modules and building components from the scope of an assessment using the include toggles in each section of the request body. When comparing results between C.Scale and other tools, or between any estimates of carbon emissions, the scope of each analysis must be identical.

Uncertainty

Inclusion of an uncertainty estimate is coming soon to the public web application.

Anecdotal evidence has put C.Scale results (modeled without any customization) within 5-30% of the estimates generated by whole building Life Cycle Assessment and hourly operational carbon assessment for buildings where C.Scale was used either in early project stages or post facto.

Customizing any model parameters will remove them from the calculation of uncertainty. We assume that custom data represents commitments made by the project team.

After constructing scenarios, they can be compared in the "Compare" tab. Typically, multiple strategies for reducing carbon emissions are under consideration in the early project phases. In C.Scale, these strategies can be compared graphically and numerically.

Emissions Over Time

This figure compares each scenario to the baseline across the analysis period.

Note that some carbon reduction measures can actually increase emissions, an effect that can lead to confusion in interpreting the Cumulative Emissions Over Time figure. For instance, substituting the structural system can increase or decrease the embodied emissions depending on the nature of the change, or the addition of a PV array incurs embodied emissions even if it lower operational emissions over time. Accordingly, the patterns in this figure require interpretation based on the carbon reduction measures modeled for each scenario.

Emissions Summary

This figure compares the cumulative emissions for each scenario at the end of the analysis period.

In addition to comparing magnitude of emissions at the end of the analysis period, this chart is useful for comparing the proportion of emissions between scenarios. In comparing these proportions, however, please note the selected analysis period. Operational emissions accrue over time, so the proportion of embodied to operational emissions is highly sensitive to the study's time horizon. The time horizon in C.Scale is shorter than those most often used in wbLCA in order to support project teams in meeting time-based climate targets.

This chart has a number of elements:

• Reduction from Baseline. Cumulative reduction in emissions of the current scenario as compared to the baseline.

• Refrigerant Emissions. Cumulative emissions associated with the refrigerant use in the building services.

• Electricity Emissions. Cumulative emissions associated with the energy use from the electrical grid.

• Fossil Fuel Emissions. Cumulative emissions associated with onsite fossil fuel use.

• Embodied carbon emissions. Cumulative emissions associated with building materials, their replacements, and with landscape maintenance.

• Biogenic Carbon. Sequestered emissions from building structure and landscape planting.

• Avoided Energy Emissions. Avoided emissions from onsite energy generation in excess of use.

The following settings are applied at the portfolio level, meaning they affect the target scenario for each project. This ensures that all projects within the portfolio share the same underlying assumptions, making them comparable.

To refine the portfolio, click on All Portfolio Settings in the left-hand panel.

Scope

C.Scale allows project teams to refine the scope of analysis at the portfolio-level by including or excluding LCA stages or parts of the building to meet reporting goals or to facilitate comparison within the portfolio.

Any decarbonization measures in excluded parts of the portfolio scope are still saved with the portfolio, but will become temporarily unavailable as long as they are out of scope. When their scope is restored, the values will reappear as last entered.

Analysis Period

Select an analysis period to determine over how many years the analysis takes place.

Life Cycle Stages

A4-A5 (Construction Process) Turning off this toggle will remove construction process emissions—counted in the A4 and A5 life cycle stages—from the C.Scale model.

D, Biogenic Carbon Storage, and Avoided Emissions Turning off this toggle will remove biogenic carbon stored in timber structural elements, carbon sequestered in landscape, and emissions avoided by excess energy production from on-site renewable from the C.Scale model.

Scope Categories

Structure Structure and Foundations are always included.

Enclosure Turning off this toggle will remove the embodied carbon associated with cladding, glazing, and roofing from the C.Scale model.

Interior Turning off this toggle will remove the embodied carbon associated with interior fitouts from the C.Scale model.

Services Turning off this toggle will remove the embodied carbon associated with MEP and PV Arrays (the energy generated by PV panels will still be included).

Refrigerants Turning off this toggle will remove the emissions associated with refrigerant use in the building.

Sitework Turning off this toggle will remove all site and landscaping from the C.Scale model.

General

Unit System

Modify the unit system for the portfolio's calculations.

Electricity Grid

Future Scenario

• Expected decarbonization. Average estimates for inputs such as technology costs, fuel prices, and demand growth. No inclusion of nascent technologies. Electric sector policies as they existed in September 2022, with the assumption that the Inflation Reduction Act’s Production and Investment Tax Credits do not phase out. This metric is described in NREL's Cambium model as "Midcase."

• Slow Decarbonization. Average estimates as in the mid-case scenario, but with an assumption that battery and renewable energy costs are high. This scenario assumes that the thresholds set by the Inflation Reduction Act’s Production and Investment Tax Credits are not met and, as such, they do not phase out. This metric is described in NREL's Cambium model as "High Cost of Renewable Energy."

• Rapid Decarbonization. Average estimates for inputs such as technology costs, fuel prices, and demand growth. Nascent technologies are included. Electric sector policies as they existed in September 2022, with the assumption that the Inflation Reduction Act’s Production and Investment Tax Credits do not phase out. High-level assumption that the national electricity grid's carbon emissions in 2050 are 5% of their 2005 level. This metric is described in NREL's Cambium model as "95% decarbonization by 2050."

Emission Metric

• Average Emission Rate (AER). By default, C.Scale measures annual emission factors by summing the total generation of all resources in a given year and putting them on a MWh basis. This average emission rate also includes 'precombustion emissions from the leakage of fossil gas in the energy supply chain. This metric is described in NREL's Cambium model as "AER Load: Combustion + Precombustion."

• Long-Run Marginal Emission Rates (LRMER). LRMER emissions are described by NREL as emission rates for “of the next unit of electricity considering the grid’s structure as variable.” This emission metric is preferable to a simple average emission rate because buildings are long-lived assets whose demand for energy has a marginal influence on the evolution of the energy grid. This metric is described in NREL's Cambium model as "LRMER: Combustion + Precombustion."

Embodied Carbon in Building Structure

Embodied carbon in building structure is calculated in two stages: a bill of structural materials is estimated and carbon intensities are applied to those materials.

C.Scale's estimation of embodied carbon in a building's structure is modeled based on machine learning models built from over bills of material from real buildings. This approach is preferable to a first-principles approach—i.e. assuming an optimized structural grid for a given geometry—because it greatly reduces truncation error and better describes the variation present in real buildings.

Calculating a Bill of Materials

C.Scale uses a suite of machine learning models to estimate quantities of major structural materials in typical buildings. These models were trained from an C.Scale database of structural quantities in completed buildings (n > 1200) assembled from both internal and public sources. The models are updated regularly as new data becomes available.

These weighted data is used to train a statistical model for each structural material in each structural system. These models are trained on a small set of predictors from the underlying data set.

Training data is divided into 80% training data and 20% data. Each bill of materials is weighted relative the data provenance. LCI data from a detailed wbLCA is given the highest weight, with data from journal articles, white papers, partial data, and modeled data given progressively lower weights.

There are five ML models in our model pipeline. The least accurate model in our pipeline has a Mean Absolute Percentage Error of 16.7% and an r2 value of 0.74. The four other models each have an r2 value over 0.95. K-folds cross-validation (n=5) is used to confirm that each models can consistently predict unseen data.

C.Scale uses an instance of this modeling pipeline served in the cloud to generate a bill of materials 'live' as a user requests data from our API.

These methods for calculating a structural bill of materials have been reviewed by colleagues at MKA, Carbon Leadership Forum, and Autodesk with additional comment from colleagues at Arup. If you are a structural engineer or data scientist interested in providing further review of our modeling pipeline, please reach out.

Known issues with the structural bill or materials generation models are an overprediction of material quantities for small industrial warehouses and rare combinations of use category and primary structural material (e.g. light wood frame hospitals).

Carbon Intensities of Structural Materials

Carbon intensity is the amount of CO2-equivalent emissions per unit of material. For structural materials, carbon intensity information is drawn from a variety of sources. In all cases, C.Scale uses GWP-100 characterization factors. These sources are documented in the Reference Data Sources section of this guide.

The three specifications available in C.Scale—low carbon, best practices, and conservative—correspond to the 20th, 50th, and 80th percentile of emissions for that material. These estimates do not correspond to a specific EPD, as there are many options for achieving a certain level of performance. Most carbon intensities for structural materials in C.Scale are national averages, as material supply chains for major structural materials are typically national (or global) in coverage.

Concrete emissions, on the other hand, as assessed regionally. Concrete is a local material, rarely traveling more than 25 miles between production and use. Additionally, the relatively large number of concrete EPDs available in the United States (80,000+) supports a regional approach to measuring concrete emissions.

When specific data is not known, the API includes three choices carbon intensities, defined by the range of products or assemblies available in a particular location:

• Conservative represents the 80th percentile of carbon intensities for regionally-available material or assemblies.

• Best Practices represents the 50th percentile of carbon intensities for regionally-available material or assemblies.

• Low Carbon represents the 20th percentile of carbon intensities for regionally-available material or assemblies.

Regionalization of Carbon Intensity Data

Wherever feasible, carbon intensity data is regionalized to the appropriate level of resolution. Our regionalization methodology aims to reflect the products and assemblies available in a region (the "market mix"), which is often distinct from those manufactured in that region (the "production mix").

Our API includes country-level data for the following countries: United States of America, Canada, United Kingdom, Denmark, France, Germany, Italy, Norway, Saudi Arabia, United Arab Emirates, Singapore, and Sweden. Where regional data is not available, we use background data specific to the region. Currently, we maintain background datasets for North America, the EU, and "rest of world" (RoW).

The overview of how C.Scale calculated operational carbon is detailed on the model structure page. Below, we give additional detail about how C.Scale calculates emissions from all the sources contributing to a project's operational carbon.

Overview of Operational Carbon Calculation

The operational emissions of the project are assessed annually and summed across all years before the target date. The equation is similar to the equation for embodied emissions, with two key differences: first, the quantity x is substituted for the energy use intensity (EUI) e; second, the equation is a double summation, once across all the fuel types in the building and again across all years between the building’s completion and the target year. The total operational emissions assessed by C.Scale are represented by this expression:

Carbon emissions associated with electricity are derived from NREL's Cambium model. Onsite fossil fuel use is assumed to be natural gas. The carbon emissions of natural gas are assessed with a 2.4% leakage rate. Fuel oil emissions account for N20 and CH4 emissions. Characterization of non-CO2 emissions is determined with the GWP100 factors published in IPCC AR6.

Energy Use

C.Scale uses energy use intensity (EUI) in units of kBtu/sf/yr (or kWh/m2/yr) as its metric for energy use in buildings. C.Scale is designed to give accurate feedback on the carbon emissions associated with a declared energy use, but is not an energy modeling tool for determining how a declared energy use can be achieved.

Baseline EUIs are set in c.scale using a direct API connection with Architecture 2030's Zero Tool, with a failover to a subset of cached Zero Tool results. Zero Tool estimates are used to set baselines for AIA 2030 reporting, but should not be construed as representing "code minimum" design. To set a code minimum EUI, enter your desired value as the benchmark_EUI in the request object.

Fuel Mix

Benchmark buildings are assumed to be "mixed fuel," using energy from both electricity and onsite combustion. All onsite combustion is assumed to be natural gas. The fuel mix of buildings is calculated to align with assumptions in Architecture 2030's Zero Tool. Zero Tool estimates are used to set baselines for AIA 2030 reporting, but should not be construed as representing "code minimum" design.

C.Scale assumes a 2.4% upstream leakage rate for all fossil fuel combusted in a building. The carbon intensity of this leakage is calculated with characterization factors from the IPCC's AR6.

Fuel Mix in Canadian Buildings

Fossil fuel usage at the building level is reported by Energy Star. This data represents the average fuel mix used across all existing building stock within each province. Building use category is not factored into this data.

In order to fill in the data gap for the Northwest Territories, Nunavut, and Yukon, the data representing the prairies region (Alberta, Manitoba, and Saskatchewan) was used. The assumption is that the territories are likely to be more reliant on fossil fuels given that they have less developed infrastructure for the transmission of electricity due to how remote they are.

Carbon Intensity of Electricity

C.Scale includes estimates of carbon emissions from demand for electricity from now until 2110. These estimates are based on NREL's Cambium capacity expansion model. If you are curious about the underlying data, you can explore Cambium data in NREL's online scenario viewer. Cambium data is not available annually, but annual data is necessary in C.Scale. To annualize Cambium data, we use the following method:

• Fill temporal gaps in Cambium data from 2024-2050 with geometric interpolation for all years between two years reported in Cambium.

  • I.e. for 2025 between the reported values in 2024 and 2026, or for 2041-2044 between the reported values in 2040 and 2045.

• Extend data to 2110 assuming the electricity grid continue to decarbonize at the same average rate that it decarbonized from 2024-2050. Note that the end date of 2110 has no basis in the data; 2110 is only chosen so that C.Scale can model a 60 year reference period for buildings completed up to the year 2050.

• Fill geographic gaps to give wall-to-wall coverage of United States.

  • C.Scale assumes the average emission rate in Washington, DC, is the same as in Virginia (highly interconnected grids, both PJM).

  • For Alaska and Hawaii, we assume exponential reductions that allow them to meet their climate goals (in the mid-case scenario) or get to 95% decarb by 2045. We don’t make an assumption to approximate a scenario like High Cost of Renewable Energy for either of these two states.

Electrical grid emission metrics

C.Scale includes two metrics for grid emissions.

• Average Emission Rate (AER). By default, C.Scale measures annual emission factors by summing the total generation of all resources in a given year and putting them on a MWh basis. This average emission rate also includes 'precombustion emissions from the leakage of fossil gas in the energy supply chain. This metric is described in NREL's Cambium model as "AER Load: Combustion + Precombustion."

• Long-Run Marginal Emission Rates (LRMER). LRMER emissions are described by NREL as emission rates for “of the next unit of electricity considering the grid’s structure as variable.” This emission metric is preferable to a simple average emission rate because buildings are long-lived assets whose demand for energy has a marginal influence on the evolution of the energy grid. This metric is described in NREL's Cambium model as "LRMER: Combustion + Precombustion."

Electrical grid projections

The future of the electrical grid is uncertain. To account for this uncertainty, C.Scale includes three future grid scenarios in each region.

C.Scale evaluates energy use on an annual basis. The carbon emissions from electricity, however, vary hour by hour. Depending on the use type and location, this can lead to a difference of as much as +/- 20% between annual (modeled) and hourly (measured) estimates of operational emissions.

Energy Generation from Onsite Renewables

C.Scale calculates energy generation from onsite solar photovoltaic arrays using an API connection to Version 8 of NREL's PVWatts tool. This energy is assumed to displace an equivalent amount of energy demand from the electrical grid and, by doing so, displace a corresponding quantity of emissions (calculated using the Cambium data detailed above).

The array area returned by the c.scale is the total area of the array (i.e., inclusive of the space between the panels). The ratio of solar panels to total array area is the Ground Coverage Ratio (GCR).

PVWatts is limited to latitudes from -60 to +60 degrees. For latitudes outside this range, we calculate solar potential at the limit (either -60 or +60). If you're using C.Scale to model a PV array at extreme latitudes, use caution.

Envelope Quantity Takeoffs

The building envelope in divided into three components: opaque cladding, glazing, and roofing. The area of each is calculated based on user inputs for building floor area, number of floors, floor-to-floor height window-to-wall ratio (WWR), and building perimeter. C.Scale makes a preliminary estimate of floor-to-floor height, WWR, and building perimeter (assuming a square building) which the user can refine in the "overrides" panel in the base case tab.

Floor-to-Floor Height

Floor to floor (F2F) height can be set in the API for each floor individually (if using the stacked BuildingForm object) or for all floors together (in the simple BuildingForm object). Default values for floor-to-floor height are set by use type, as described in the table below.

Parametric Envelope Model

C.Scale includes a dynamic envelope model which allows users to input very general data (when very little is known) or very specific data (during later stages of design).

When specific data is not known, the API includes C.Scale's pre-defined carbon intensities, defined by the levels of ambition:

• Conservative represents the 80th percentile of material or assembly carbon intensities.

• Best Practices represents the 50th percentile of material or assembly carbon intensities.

• Low Carbon represents the 20th percentile of material or assembly carbon intensities.

When more data is available, C.Scale allows you to define specific cladding assemblies, exterior insulation types, and wall framing assemblies. Using the description parameter in the envelope.cladding or envelope.glazing section of the request, you can pass in a more precise definition of the opaque building envelope. Where one or more layers of the assembly is unknown (or up for discussion, pass a None parameter.

C.Scale will use your description of the envelope (i.e., any declarations of specific materials) to subset our library of envelope assemblies (~1200) to only those meeting your criteria. The API will use the relevant specification parameter to choose the 20th, 50th, or 80th percentile of that subset. This allows the user to know the range of potential carbon intensities available both within and between their declared design.

• If all parameters are None (no design criteria entered), then we evaluate the percentile from the full set of envelopes in our database (~1200 modeled envelope assemblies).

• With the user selects their design criteria, we subset the data used to generate these percentiles. For instance, if a user selects a Timber Rainscreen cladding, we will return the 20th, 50th, of 80th percentile of all envelope assemblies in our database with a Timber Rainscreen (~100 modeled envelope assemblies).

Multiple envelopes can be described for a building by passing a list of descriptions. The relative proportion of each envelope is described with the proportion field with each description. The API will normalize all proportion entries to the total opaque envelope area. This means that a use can pass in proportions of 20000, 25000, and 5000 (representing m2 of envelope area) or of 0.4, 0.5, and 0.1 (representing the same assemblies as proportions of the total).

In all cases, user-declared carbon intensity data can be entered on a kgCO2e/m2 (of kgCO2e/sf) basis for each component of the envelope.

Opaque Envelope

Data in the C.Scale envelope model makes use of Payette Kaleidoscope data for some assemblies by permission. Find the full citation for these data in the Reference Data section of the methodology.

Default R-Values

The declared R-value of the assembly is used to calculate the amount of exterior insulation needed. R-values for framing assemblies are de-rated using the nominal R-values in ASHRAE 90.1-2019 Appendix A. If an R-value is not declared by the user, the default is set by climate zone.

Transparent Envelope

Roofing

Parametric roofing model coming soon!

C.Scale generates detailed time series estimates of a building's embodied carbon emissions and organizes those emissions into the appropriate life cycle stages.

A1-3: Upstream Product Emissions

A1-A3 emissions are calculated from a bill of materials (e.g., life cycle inventory) inferred from the user's description of a building. The exact method for generating that bill of materials and performing calculation of A1-A3 emissions vary by building assembly.

For each contributor $i$, embodied emissions in life cycle stages A1-A3 are assessed with the following expression:

Where A is the total building area, $x_i$ is the quantity of the contributor $i$ per building area, and $c_i$ is the carbon intensity per unit of the contributor $i$.

For example, a 10,000 square foot building may use 4 pounds of reinforcing steel per square foot of floor area, and the reinforcing steel may have a carbon intensity of 500 grams (0.5 kilograms) of carbon dioxide-equivalent emissions per pound of steel (values for illustrative purposes only). Taking the product of these three hypothetical quantities yields the contribution of reinforcing steel to that building’s embodied carbon emission:

Other pages in this section detail the calculation of A1-A3 emissions from structure, envelope, and other building assemblies.

A4-5: Construction Emissions

A4: Transportation of Materials to Site

All materials accounted for in A1-A3 must be transported to site. C.Scale defaults to emission factors from the ASHRAE 240P draft guidance in table 6.5.2.1. These are conservative estimates of emissions per quantity material. These data include a 0.5 return trip factor.

A5.1: Pre-Construction Demolition

Pre-construction demolition emissions are calculated per floor area of the demolished building, using a default factor of 35 kgCO2e/m2. This is a data-scarce category. Where project-specific data is available, this default can be overridden by the user.

A5.2: Jobsite Activities

Emissions from construction activities and land use change are included in A5.2.

Construction Activities

Construction activities include the use of tools, fuel, equipment, and energy on the building site. This includes site preparation, installation of materials, and other jobsite activities. As a default value, C.Scale assumes the carbon intensity of construction activities to be 40 kgCO2e/m2 of project floor area. Where project-specific data is available, this default can be overridden by the user.

Emissions from construction activities are proportioned out to categories by the proportion of their A1-A3 emissions. For example, if a building's envelope accounts for 25% of its total A1-A3 emissions, C.Scale assumes the A5.2 construction activities associated with enveloped are 10 kgCO2e/m2, 25% of the default value of 40kgCO2e/m2. Or, if the user has entered a custom carbon intensity for A5.2, the model will calculate 25% of that value instead.

Emissions from Greenfield Development

Land use change emissions from greenfield development are counted in A5.2. When a user enters a site area, they have the option to select whether or not the site has been previously developed. If the site has been previously developed, C.Scale treats it as a "brownfield" site with no carbon sequestered in its soil and existing landscape. If the site has not been previously developed, C.Scale treats it as a "greenfield" site with preexisting vegetation.

Developing a greenfield site releases carbon emissions from two sources: carbon stored in soil and carbon stored in biomass. C.Scale assumes that 100% of the carbon stored in topsoil is emitted as carbon dioxide. Data on carbon storage in soil is highly regional, and C.Scale uses FAO's Global Soil Organic Carbon data product for this calculation, taking the mean value at the zip code level.

To calculate emissions from the removal of above ground biomass, C.Scale treats the site as vegetated with regionally-specific "low carbon storage" plants at 50% of the site's carrying capacity. More information on how carbon storage in living biomass is calculated in C.Scale is available in the Stored and Avoided Carbon section of the methodology.

A5.3: Jobsite Waste

For each material and building assembly, C.Scale assumes a percentage of the installed total is wasted during construction. For all waste incurred during A5.3, we calculate A1-A4 and C2-C4 emissions for the wasted material and assign it to A5.3 emission for that material's category. C.Scale's default (conservative!) waste rates are included in the table below.

B Phase: Use Stage

The use stage includes all emissions from the operation of the building from the completion of construction until the end of the reference service period.

B1: In-Use Emissions

Fugitive emissions from annual refrigerant leakage, as well as refrigerant leakage for equipment replaced during the operating life of the building, are counted in life cycle stage B1. This is treated in detail in the documentation section on Refrigerant Emissions.

Annual carbon storage in landscape is also included in this phase.

B2-B5: Replacement and Refurbishment

C.Scale uses a simplified model of replacement and refurbishment. For all materials in the C.Scale model, the emissions associated with these replacement and refurbishment—including manufacturing, transportation, and installation of the new materials, as well as end-of-life emissions for any removed materials—are assigned to the year(s) determined by the user-selected refurbishment period.

B6: Operational Energy use

Life cycle stage B6 includes operational emissions from energy use. This is treated in detail in the documentation section on Operational Carbon.

C Phase: End of Life

Data from life cycle stages C1-C4 cover the process from building demolition to final disposition of materials, as input to recycling, waste recovery processes, or to a landfill.

C1: Demolition

C.Scale assumes that business-as-usual demolition practices will 30% of the emissions used to construct the same asset. This value can be overridden with a project-specific value. C1 also includes emissions from refrigerant leakage of all removed equipment.

C2: Transportation to End of Life Processing

By default, C.Scale assumes that all waste travels 50 miles (80 km) to the nearest waste processing facility by truck with a 50% load. This distance can be overridden by user inputs.

C3: Waste Processing for Recycling, Reuse, and Recovery

Data for life cycle stages C3 are collected from regionally-appropriate industry-average EPDs.

C4: Landfill Disposal Emissions

Data for life cycle stages C3 are collected from regionally-appropriate industry-average EPDs. Where data is not available in the US, EPA Warm is used a reference data source.

D Phase: Benefits Beyond the System Boundary

The D phase of a whole life carbon assessment includes environmental benefits and burdens beyond the system boundary. D phase emissions are typically reported separately from life cycle impacts.

D1: Potential Benefits from Recycling, Recovery, and Reuse

Data for life cycle stages D1 are collected from regionally-appropriate industry-average EPDs. Where this data was not available, we assume D1 to be zero.

D2: Benefits from Exported Energy

Once production from an onsite solar array has exceeded annual electricity use, C.Scale assumes all additional energy generated by the array displaces generation of electricity by the electrical grid. The avoided emissions from surplus onsite energy generation are calculated as the emissions that this displaced energy would have incurred.

This method assumes that there is no curtailment of PV production, and that the carbon emissions of grid electricity when solar energy is produced is substantially similar to the annual average emissions. In locations with a high proportion of solar on the grid, these assumptions will not hold and skepticism of C.Scale's calculation of avoided emissions is warranted. Read more about curtailment in this publication (pdf) from there National Renewable Energy Laboratory.

The assumption of displacement generation will not hold true in all locations, and some skepticism of this estimate is encouraged. Two interrelated situations where C.Scale's assumptions of displaced generation will not hold are when:

• Daytime (i.e., when solar is available) emissions from the electrical grid are significantly lower than the national average.

• Surplus energy generation is expected to be curtailed by the utility. For an overview of curtailment in the United States, we recommend this report from NREL (pdf).

The generation of excess energy by an onsite solar photovoltaic array displaces the generation an equivalent amount of electricity from the utility grid. This is calculated as follows:

Where $e_{t}$ is the excess energy in kWh generated in year $t$ and $c_{t}$ is the carbon intensity of the electrical grid per unit demand in year $t$. This method assumes that there is no curtailment of PV production, and that the carbon emissions of grid electricity when solar energy is produced is substantially similar to the annual average emissions. In locations with a high proportion of solar on the grid, curtailment is likely and skepticism of C.Scale's calculation of avoided emissions is warranted.

If you are interested in further analysis of hourly emissions, please reach out.

In C.Scale, fugitive emissions from refrigerant leakage are categorized as operational emissions. They are counted in life cycle stage B1.

For each year of operation, emissions from refrigerant leakage are calculated as:

For each year where MEP systems are replaced/refurbished (denoted in C.Scale as the “refurbishment period”), emissions from refrigerant leakage are calculated as:

Estimating Total Refrigerant Charge

Estimates of total building refrigerant charge are based on data in Barbara Rodriguez’s dissertation entitled "Embodied Carbon of Heating, Ventilation, Air Conditioning and Refrigerants (HVAC+R) Systems." These data are collected from a sample of 20 LEED-certified buildings in the Pacific Northwest region of the United States.

Refrigerant Leakage Rates

Annual and end-of-life refrigerant leakage rates are typically a model assumption, not a carbon reduction measures. In C.Scale, there are two options for leakage assumptions.

Refrigerant GWP

Throughout C.Scale, three options are given for specification-related options: Conservative, Best Practices, and Low Carbon. Typically, these refer to the 20th, 50th, and 80th percentile of GWP values for available materials. We were unable to replicate this methodology for refrigerants, though, as the overall distribution of refrigerants skews very high–and this highly skewed distribution doesn’t represent the choices designers are making on their projects. In the refrigerant model, these three choices are keyed to specific refrigerants as follows:

C.Scale values your privacy and is committed to protecting your personal information when you use our C.Scale web application. This Privacy Policy explains how we collect, use, and secure your data. This policy may be updated periodically, and we will inform you of significant changes by updating the “Last Updated” date and posting the revised policy on this page.

2. Information We Collect

We collect several types of information to improve your experience with C.Scale. The first type is personal information, which includes details you provide to create an account, such as your name and email address. This information helps us manage your account and facilitate communication with you.

Additionally, we collect non-identifiable usage data which allows us to analyze how users interact with C.Scale, such as which pages are visited and which features are used. These insights help us to make informed improvements to C.Scale and better support user needs.

Finally, we handle project data that you upload to C.Scale, which is securely stored and anonymized to protect your privacy. Project data is not connected to any personally identifying information and is accessible only to authorized C.Scale personnel for occasional database maintenance tasks.

3. Use of Your Information

The information we collect is used for purposes that directly benefit your interaction with C.Scale. We use your data to create and manage your account, communicate important updates, and support technical maintenance. Usage data specifically enables us to assess the functionality and performance of C.Scale, ensuring it remains effective and reliable. When you contact us with questions, we may reference your user data to provide timely assistance and resolve issues efficiently.

In cases of security notifications or mandatory service updates, we will reach out to you directly to ensure you are informed of any critical changes affecting C.Scale.

4. Data Storage and Security

All data collected through C.Scale is stored on secure servers in the United States. Our data security measures include SSL/TLS encryption for data transmissions and AES-256 encryption for data at rest within MongoDB Atlas, our database provider. These security protocols are further supported by AWS’s multi-layered protection and a dedicated firewall, ensuring that data remains secure against unauthorized access.

Our user management and authentication provider (Clerk) adheres to SOC 2 Type II and GDPR standards. Only authorized personnel have controlled access to any raw data, allowing us to perform necessary maintenance without compromising privacy. Throughout the organization, we maintain a strict "principle of least privilege" approach to handling any sensitive data.

5. Data Retention

We retain data for various periods based on its type and purpose. Account data, for example, is retained for up to 30 days after an account is deleted to allow for recovery if needed. Usage data, as handled by our analytics tools, follows the retention standards set by Google Analytics and Mixpanel. Project data is stored only as long as necessary for maintenance and functional improvements within C.Scale.

This approach allows us to balance data retention needs with privacy considerations, ensuring we store data only as long as it directly benefits C.Scale’s operation and your user experience.

6. Your Privacy Rights

For California residents, this Privacy Policy aligns with the California Consumer Privacy Act (CCPA), granting you the right to inquire about personal data collection, request deletion, and opt out of data sales. While we do not sell personal data, we are committed to honoring all applicable rights for California residents.

Additionally, C.Scale respects “Do Not Track” settings, and we do not track user activities or plant cookies if this setting is enabled in your browser.

7. Third-Party Services

To understand and improve C.Scale’s functionality, we use third-party tools liek Google Analytics to help us evaluate website usage patterns, and to understand user interactions within the application. You can opt out of Google Analytics by using their Opt-Out Browser Add-on.

These third-party services support our commitment to optimizing C.Scale for a better user experience. However, we ensure they do not collect personal information beyond what is essential for analysis and improvement.

8. Children’s Privacy

C.Scale is not designed for individuals under 13 years of age. We do not knowingly collect information from children. If we become aware that a child has provided personal data, we will promptly delete this information to maintain compliance with relevant privacy laws.

9. Contact Information

10. Updates to This Policy

We may periodically update this policy to reflect changes in our data practices or applicable laws. Any updates will be posted on this page, and we will revise the “Last Updated” date to indicate the latest version.

Embodied Carbon in Building Assembles

Building assemblies in C.Scale are evaluated on a per-area basis. When specific data is not known, the API includes C.Scale's pre-defined carbon intensities, defined by the levels of ambition:

• Conservative represents the 80th percentile of material or assembly carbon intensities.

• Best Practices represents the 50th percentile of material or assembly carbon intensities.

• Low Carbon represents the 20th percentile of material or assembly carbon intensities.

For each assembly, the carbon intensity is determined by sampling the distribution of GWP values from typical assemblies at the 20th, 50th, and 80th percentile.

Embodied Carbon in Interior Fit Out

Interior fit out is calculated on a per area basis for a proportion of the building's total area. Note that the dataset used to generate the quantities used in C.Scale is not sensitive to use type and is biased toward commercial interiors. These data include internal C.Scale data and data from the CLF study on tenant fit outs in commercial office buildings.

A custom carbon intensity of interior fitout can be entered by passing a kgCO2e per area value directly to the API. The area basis for this calculation is the total floor area multiplied by the percentage of floor area with an interior fit out.

Embodied Carbon in MEP Systems

Embodied carbon in mechanical systems in evaluated at two specification levels—standard performance and high performance—and is dependent of the total square footage of the building. This approach, and the data used in C.Scale, follow from the CLF study on building mechanical systems.

A custom carbon intensity of MEP systems can be entered by passing a kgCO2e per area (sf or m2, depending on the unit system) value directly to the API. The area basis for this calculation is the total floor area multiplied by the percentage of conditioned floor area.

Embodied Carbon in Solar Photovoltaic Arrays

A custom carbon intensity of PV Array can be entered by passing a kgCO2e per area (sf or m2, depending on the unit system) value directly to the API. The area basis for this calculation is the total panel area (i.e., not the total array area). The panel area is calculated as the array area divided by the ground coverage ratio.

Embodied Carbon in Hardscape

All site area not designated as planted is assumed to be hardscaped. Hardscape emissions were calculated by C.Scale using a parameterized streamlined LCA model of built from standard hardscape details. The 20th, 50th, and 80th percentile of the resulting distribution was sampled and used to define the specification levels in C.Scale.

A custom carbon intensity of hardscape can be entered by passing a kgCO2e per area (sf or m2, depending on the unit system) value directly to the API. The hardscape area is assumed to be the total site area less the building footprint and and plantings.

Emissions from Landscape Maintenance

Example Data

Overview

In C.Scale, landscaping and the use of structural timber contribute to biogenic carbon storage. Carbon storage in structural materials is assessed once in the first year of the project, and landscape sequestration is assessed each year. Biogenic carbon sequestration is evaluated with the following expression:

Biogenic Carbon

Living systems present a particular challenge for carbon emission accounting. Static emission factors are sufficient for manmade or mineral materials, but biogenic materials—those materials, such as forest products, originating from living systems—can’t be as easily summarized. Through photosynthesis, living materials remove carbon from the atmosphere as they grow; the removal of carbon dioxide from the atmosphere and its storage in biogenic materials is called referred to in C.Scale as "carbon storage." But there are also emissions associated with the processing and maintenance of biogenic materials. And, eventually, biogenic materials are stored in landfills where they continue to store carbon, are recycled, or are combusted for energy and release their stored carbon back into the atmosphere.

Carbon storage in timber

To account for the life cycle emissions of biogenic materials including carbon storage, C.Scale follows the recent guidance of the American Center for Life Cycle Assessment (ACLCA) in accounting for their carbon emissions (see citation in Data and References). This guidance is applied to accounting for the biogenic carbon in forest products (lumber, plywood, and mass timber assemblies) as well as to biogenic carbon stored in the landscape. To understand the tradeoffs in biogenic materials, life cycle stages for the end-of-life of biogenic materials are counted upfront, even if they aren’t included for other products.

In C.Scale, the emissions and carbon storage associated with biogenic structural materials are accounted for at the beginning of the project.

The carbon emitted in the production of biogenic materials is accounted separately from stored biogenic carbon. The carbon emissions related to material production (arising from processes such as the use of machinery and transportation) are counted as embodied carbon.

Carbon storage in lumber, plywood, and mass timber assemblies can only be counted if those materials are sourced from responsibly managed forests. Practically, this can mean a number of things. In C.Scale, we identify three criteria contributing to the claim that wood products are responsibly sourced. While C.Scale does not prevent the user from counting the carbon storage benefits on other terms (as the list below is nonexhaustive), we recommend meeting at least two out of the three criteria below in order to claim climate benefits from carbon storage:

• Transparency and traceability in the supply chain (required). Transparency and traceability in the supply chain. Claims can be made about the environmental attributes of timber are impossible to verify without transparency and traceability in the supply chain. This means that a project team should be able to identify:

  1. The source forest(s) or supply area(s)

     • This is the area from which a primary manufacturer sources most or all of its logs, typically a circle drawn around the location of the site of the mill, with the size being dictated by the maximum hauling distance of the logs.

  2. The primary manufacturer mill(s)

     • E.g., sawmill, veneer mill, chip mill, etc.

  3. The fabrication shop (for engineered timber).

• Increasing forest carbon stocks (optional). Carbon storage in wood products can only be claimed if the carbon stock of the source forest is maintained or increasing. This means that the forest area is managed and regenerates in a way that either preserves or increases the average level of carbon stored in vegetation and soils, or that high conservation value or high carbon stock forests are not replaced by less ecological valuable and carbon rich production forests.

• Certified, recycled, or reclaimed wood (optional). The use of recycled or reclaimed wood prolongs its storage of carbon and can displace the use of virgin timber. Certification by the Forest Stewardship Council (FSC) ensures that sound forestry, audit, and reporting practices are used.

C.Scale assumes that lumber, plywood, and mass timber assemblies are landfilled, recycled, or combusted for energy at the end of their useful life. The mix of landfilling, combustion, and recycling is determined by the EPA analysis of US disposal in 2018. The emissions from these three activities are calculated with the EPA’s Waste Reduction Model (v15).

Carbon storage in planted areas

C.Scale measures the annual carbon storage of in living and growing landscape. We assume that all plantings will achieve maturity across the building project's reference period. Carbon storage in the landscape is accrued year over year by amortizing the total carbon storage in mature landscapes over the model's reference period.

In C.Scale, landscaped area is assumed to approach its maximum storage potential (its "carrying capacity") over a 60-year period. The amount of carbon that a landscape can store is location-dependent (i.e., a landscape in Miami can store more carbon than one of a similar size in Arizona).

Maintaining carbon storage in landscape requires maintenance. Emissions from the maintenance of carbon-storing landscape are assessed as embodied emissions. The storage potential of a landscape or green roof depends on its area, its specification (low, moderate, or high storage), and the location of the project.

Land use change emissions

Avoided emissions from surplus energy generation

Once production from an onsite solar array has exceeded annual electricity use, C.Scale assumes all additional energy generated by the array displaces generation of electricity by the electrical grid. The avoided emissions from surplus onsite energy generation are calculated as the emissions that this displaced energy would have incurred.

The assumption of displacement generation will not hold true in all locations, and some skepticism of this estimate is encouraged. Two interrelated situations where C.Scale's assumptions of displaced generation will not hold are when:

• Daytime (i.e., when solar is available) emissions from the electrical grid are significantly lower than the national average.

The generation of excess energy by an onsite solar photovoltaic array displaces the generation an equivalent amount of electricity from the utility grid. This is calculated as follows:

Embodied Carbon Emissions

Operational Carbon Emissions

Carbon Storage and Sequestration

*Full citation for Payette’s Kaleidoscope: Payette’s Kaleidoscope Embodied Carbon Design Tool, data from Tally by Building Transparency and KT Innovations, thinkstep, and Autodesk using industry representative LCI data unless otherwise noted. Accessed in November 2023.

Reference Data via API

The regionally-specific carbon Intensity data used in C.Scale is exposed via out API at the /api/carbon-intensities endpoint. This is useful for populating tooltips and helper texts when C.Scale is integrated in your application.

C.Scale is a lightweight data model for whole life carbon assessments.

Project Team

Project Coordinator, Technical Development Jack Rusk

Data Engineering Lalyn Yu

Peer Review and Feedback

The project team owes a heartfelt thanks to the group of over 80 firms that participated in our initial closed beta, the input of whom was essential to our model's early development, and the countless users who have since offered feedback, critique, and unique use cases.

Contact

Copyright

C.Scale © 2023-2024 Climate Scale, Inc. All rights reserved.

This is a log of all updates which either affect the use of the API or are otherwise important to communicate to our users (e.g. bug fixes or performance updates requested by users). This is not an exhaustive list of updates, and many internal updates are not listed below. For a complete list of updates in a specific version, please reach out.

2.33.00

This update moves C.Scale's calculations in line with emerging whole life carbon standards, with a particular focus on how we handle replacements, refrigerants, and landscape carbon storage by phase.

Updated B2-5 Calculation

When accounting for the regular replacement and refurbishment of materials over time in modules B2-B5 (maintenance, repair, replacement, refurbishment), C.Scale now accounts for:

• Emissions from the transportation of those materials to the site (following the assumptions used in module A4),

• Emissions from the installation of that material and associated waste (following the assumptions in modules A5.2 and A5.3)

• End-of-life emissions of all removed materials (following the same assumptions in modules C2-C4).

All of these emissions are 'rolled into' the B2-5 estimate, better describing the total impact of those replacements.

Improved Refrigerant Model

Emissions from refrigerant leakage are now more richly described by life cycle module:

• Emissions from installation of MEP equipment are counted in A5.2 (jobsite emissions).

• Emissions from annual leakage are counted in B1 (in-use emissions).

• Emissions from end-of-life leakage from the replacement of MEP equipment over the project's life cycle are counted in B1 (in-use emissions).

• Emissions from the removal of MEP systems at end-of-life are counted in phase C1 (demolition emissions).

We're in the process of scoping a wider update to our refrigerant model to better predict the mass of refrigerants installed, potentially with some additional (systems-specific) refrigerant data.

Improved Site and Landscape Model

As with the refrigerants model described above, we've worked to better organize and describe landscape emissions by life cycle module:

• Land use change emissions from greenfield development are counted in A5.2 (jobsite emissions).

• Carbon storage in the landscape plantings is counted in B1 (in-use emissions).

• Recurring emissions from landscape maintenance are counted in B2-B5 (maintenance, repair, replacement, refurbishment).

2.32.00

No new data model capabilities this update, but a number of changes to make the API more robust, stable, and useful. Enjoy :)

Bulk Calculation Endpoints

In addition to better supporting the use of the API for masterplanning and larger-scale projects, we hope this update also gives our users a method for reducing the need to send large sets of concurrent requests.

Incident Reporting

Up until now, the best way to report a potential issue with the API was to email (or sometimes text) Jack. Now, we have an new incident reporting endpoint available at /api/report/incident. This endpoint logs the incident via Better Stack and then Better Stack emails, texts, Slacks (and, if it's severe, calls) the dev-on-duty to troubleshoot the incident ASAP.

We hope that this will give a stronger line of communication between our users and our team, as well as ensuring that we can meet our user's highest expectations for support and incident response times.

Additional Testing

In this update, we added additional tests to support the B2-5 bugfix we made earlier today, as well as adding an additional schema-driven testing suite that ensures that the API can handle any request within the schema's validation parameters.

2.31.00

Updates to C and D Phase Emissions

This release represents a significant improvement of how C.Scale calculates C Phase emissions. Where previously these were ambiguously grouped into a C1-C4 object, data is now available for each C phase separately. To ensure that this update is applied evenly throughout the model, we also divided the D phase into D1 and D2. With the addition of more detail, the overall phases are also still available, and the C1-C4 and D objects in the category_by_stages object are retained.A few non-breaking API changes related to this update:

• Alias'ed D to benefits in lifecycle_stages request object. This parameter now affects more phases than D. I.e., carbon storage in landscape is in B1, upstream carbon storage in timber supply chains is included in A1.

• D Phase is divided into D1 (potential recycling, reuse, and recovery benefits) and D2 (exported energy).

• A5.3 estimates will change slightly, since they now include end-of-life (C Phase) emissions for all wasted materials

New Endpoints!

We restructured the endpoints to better support the stacked building form. The current /api/calculate endpoint will continue to be supported, but is considered a legacy endpoint since it's (purposefully) schema-agnostic. Moving forward, URLs for calculate endpoints will be structured around the schema they accept. We are also deprecating the /api/summary and /api/timeseries endpoints. They're a little silly, since they just return a subset of the results for the/api/calculate. This alone is not sufficient reason for us to maintain a separate endpoint. Here's the non-breaking changes you can expect from the endpoint update:

• /api/timeseries is marked as deprecated. It will be removed from the model in Q4 2024.

• /api/summary is marked as deprecated. It will be removed from the model in Q4 2024.

• /api/calculate is marked as legacy. We will continue to support this model, even as it grows stranger from accepting too many schemas all at once.

Two new shiny endpoints for calculating whole life carbon:

• /calculate/simple-form accepts a request in a nested schema with a simple building_form request.

• /calculate/stacked-form accepts a request in a nested schema with a stacked building_form request.

ZeroTool Update

Previously, C.Scale used the public ZeroTool API provided by Architecture 2030 for EUI baselines for Canada and North America. This API is awesome, and made earlier versions of our C.Scale possible. As we scale up, though, it didn't feel right that our model depended on their server resources. From this version of C.Scale and moving forward, we're hosting our own instance of ZeroTool. In addition to lessening the load on ZeroTool, this also allows us to add more resources to the ZeroTool, helping get around a performance bottleneck. Beside this, no changes to the C.Scale side.

Uptime Monitoring

2.29.00

• StackedBuildingForm object is live and available to all users

• Update material carbon intensity data in France, Italy, and Sweden

2.28.03

• Fix bug in display (not calculation) of carbon intensities for CMUMortar and CMUBlock

2.28.01

• Minor request refactoring

• interior.percent_floor_area can now equal 0

2.28.00

• Major middleware and DevOps update

• Performance updates to Geodatabase

2.27.08

• Fixed a bug where mep.specification, solar_pv.specification, and refrigerants.GWP_specification were not being properly converted when SI was used

2.27.07

• Refactored POST /carbon-intensities endpoint to remove hyphens from structure response object

• Separated routers for /carbon-intensities and /location-data

2.27.05

• added ASHRAE_CZ and KG_CZ to regional_data response object + added descriptions

2.27.04

• Fixed bug with GetCarbonIntensities endpoint where response data was not being parsed correctly.

2.27.03

• Fix responsibly sourced timber bug in some geo's

2.27.02

• Added POST endpoints for /tokens/token-data and /carbon-intensities

2.27.01

• bugfix for 500 internal server error in /api/tokens/token-data endpoint

2.27.00

• Updated the following datasets:

  • Denmark, Germany: grid, fuel mix baselines, material carbon intensity

  • Sweden, UK, Italy, France: grid, fuel mix baselines

• Added the following regions: Australia, Spain, Belgium, EU, Finland

• Added /location-data endpoint

• Added request and response schema for /location-data endpoint

2.26.03

• Hotfix for 100% reuse on all reuse parameters

• {category.reuse} now being applied to A4, A5p3 calculations for structure, cladding, glazing, roofing,mep, interiors

2.26.01

• Bug fixes forcategory_by_stages response object

• Added demolition as a stage in response schema

2.26.00

• New A4-A5 modules in LifeCycleStages.py to reflect ASHRAE/ICC 240P

  • A4_Emissions: Transportation emissions

    • A5_Emissions: Demolition (A5.1), construction activity (A5.2), and jobsite waste (A5.3)

• Added a new A4_5Options class, which allows users to input A4 transportation emission factors, demolished_area, and A5.1 and/or A5.2 emission factors

• Added total_pv_panel_area to response_areas response object

• Added total_pv_panel_area to response_pv_data response object

• Refactored structure.custom_carbon_intensities and structure.custom_bom for better visibility in schema and to happily accept incomplete inputs.

• Requests can now have none declared anywhere

2.25.01

• Hotfixes related to schema for Cambium 2023.

• Deprecate size/performance MEP data in /carbon-intensities endpoint.

2.25.00

• Migrated from Cambium 2022 to Cambium 2023 electricity emissions data for the contiguous US

  • NREL deprecated state-level data, so our analysis increased resolution to the ReEDS Balancing Authority level.

• Interim A4-A5 refactor in preparation for alignment with ASHRAE/ICC 240P.

• Update /carbon-intensities endpoint to give better visibility into EC ranges possible for specific cladding types.

• Added description to glazing data to increase resolution.

  • Multiple glazing types

  • Multiple mullion/CW materials

• Fix refrigerant GWP bug (in flat schema only).

2.24.01

• Implemented standard 20/50/80 specification levels for MEP systems (in nested schema only)

• Added example request/response to tokens/token_data endpoint

2.24.00

• Implemented rate limiting of some tokens

• Authentication refactor to allow for more fine-grained backend permissioning

• Rewrite deployment routine

2.23.04

• added primary_structure and secondary_structure as aliases to primary_structural_system and secondary_structural_system respectively

• custom_structure refactor

• Added custom_structure alias to custom_carbon_intensities

• benchmark_EUI is now defaulted to None

• site_area is now defaulted to None

• Added subassembly refurbishment periods to EmbodiedCarbonEmissions calculations

• Aliased custom_struct_bom to custom_bom

• Rewrote CustomGrid class and its respective validations

• Added happy helpful custom_grid validation error messages

• Fixed custom_grid param to correctly display in Swagger

2.23.03

• Added working request example to swagger doc

• Fixed serializer warning with request_LatLong

• Fixed validation edge case for location: validator first checks region type and parses to correct location validator based on input

2.23.02

• Refactor schemas

• Refactored endpoints so that invalid nested schemas could properly return validation errors

2.23.01

• Replaced " with in in cladding_description/envelope.description parameter

• Added mm equivalent to cladding_description/envelope.description parameter

2.23.00

• Exposed nested c.scale request schema and perform associated refactoring to support discoverability and extensibility of the API.

  • Requests made with the legacy flat schema will be parsed to the nested schema

  • Passing the /api/payload endpoint a 'flat' request will return a nested one

  • Generally, there is more resolution within the nested schema. More specific data will always overrride more general data; any variables declared in a nested part of the schema will take precedence over top-level defintiions

• Add configurable envelope data to the calculation, based on new dataset. This is reflected in both the flat and nested schema.

• Rename minor schemas to better organize the Swagger doc

• Finally rewrite a few recalcitrant functions to async

• Add link to swagger to the API landing page.

• mod_seq_planting_percentage has been removed from the response object

2.22.02

• Fixed bug where SMQi was not responding to metric units.

• Add all CIBSE TM65 options to refrigerant leakage model.

2.22.01

• Added support for metricand SI in both the /calculate and /carbon-intensities endpoints.

2.22.00

• Internationalization!

  • country is now aliased to region and postalcode is now aliased to location.

  • Expanded list of regions to 8+ countries and RoW.

  • C.Scale now supports latitude and longitude lookups.

    • Added a new global option for region. User must input a dict object into location to use this feature.

  • Include global GeoDB.

• A new response object called regional_data has been added. This includes the request's HDD, CDD, and country.

2.21.01

• Added a new response object called category_by_stages which includes stages for structure, interior_fitout, mep, cladding, glazing, roofing, site, ref, operational_energy

• Fixed bug where EoL was being calculated even when some material categories were out of scope.

2.21.00

• BREAKING CHANGES: Some response parameters have been updated:

  • api-messages → api_messages

  • kgCO2e/sf → kgCO2e_sf

• New response objects areas, structural_carbon_intensities, emission_totals, carbon_intensities, structural_quantities, energy_data, pv_data, ref_data.

• Updated C.Scale's swagger docs to reflect new response schemas.

• The verbose toggle has now been removed. The new response object will always include all parameters.

2.20.02

• Add parameters to describe buildings with multiple structural systems:

  • secondary_structural_system accepts the same inputs as primary_structural_system

  • primary_structural_percentage accepts values (1,100] with a default value of 100

  • secondary_structural_percentage accepts values (0,99] with a default value of 0

• primary_percentage renamed primary_use_percentage to disambiguate with primary_structural_percentage

  • primary_percentage still accepted as an alias for primary_use_percentage

• secondary_percentage renamed secondary_use_percentage to disambiguate with secondary_structural_percentage

  • secondary_percentage still accepted as an alias for secondary_use_percentage

• Expose parameters to model custom grid with an annual grid decarbonization factor

2.20.01

• Fix PVWatts error for very northern locations (>60N)

• Updated refrigerant methodology

• include_ref defaults to True

2.20.00

• Migrate to FastAPI

• BREAKING CHANGES: Some grid scenario names are updated as follows:

  • HighRE → SlowDecarb

  • Decarb → RapidDecarb

• mod_seq_planting_percentage is deprecated and will be removed in a future version.

• clean_power_purchase_amount now accepts values from 0-100

• First implementation of refrigerants model

  • In 2.20.00, include_ref defaults to False. In future versions, it will default to True.

2.14.10

• Update emissions leakage per peer review;

• Fix include_site toggle bug

2.14.00

• Add failover to address ZeroTool errors.

• Remove extraneous dependencies.

• Move in-memory storage to .parquet

2.13.00

• Additional reuse parameters

• Named assemblies

• Fixed reuse bug

• Metric ingress function

Changelogs for versions prior to 2.13.00 available upon request