Goal and Scope
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.
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