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Welcome to the LifeCycleAssessment_Toolkit wiki!
This page will provide an overview of LCA concepts.
Problem Statement
Climate Emergency
Net Zero Whole Life Carbon Stages [A1-D]
Considers net zero whole life carbon, moving towards a circular economy that seeks to maintain value and utility from assets, materials and resources posing challenges of data collection and as-built verification of impacts.This would require close collaboration within the supply chain, annual reporting and offsetting of embodied carbon associated with operation, maintenance, repair and refurbishment of buildings as well as developing end-of-life scenarios.
Net Zero Embodied Carbon Stages [A1-A5]
Embodied carbon is usually used as shorthand for the Global Warming Potential impacts associated with sourcing and extracting building materials, manufacturing, construction, demolition, maintenance and end-of-life processes.
Net Zero Operational Carbon Stage [B6]
For net zero operational carbon a building’s total annual net CO2e emissions should equal zero. Closing the ‘performance gap’ where modelled building energy performance does not equate to actual in-use performance, the aim is to achieve net zero carbon for operational energy with appropriate usage.
Life Cycle Assessment (LCA)
LCA is a Whole Life Carbon (WLC) modelled Assessment used to quantify carbon emissions (Embodied & Operational) and other environmental impacts of a product or process through the life cycle stages using biophysical indicators such as Global Warming Potential, Eutrophication Potential, Ozone Depletion Potential, Smog Formation Potential, Acidification Potential, etc.
Assessment Scope
Building parts and life cycle stages included. Publicly report on the Life Cycle Stages [A1-D] covered per study.
//Diagram Whole Life Carbon BS EN 15978 Modular Reporting Structure
Environmental Product Declaration (EPD)
The typical embodied carbon datasets are cradle-to-gate [A1-A3] as there is lack of data on embodied carbon impacts for the maintenance [B2], repair [B3], refurbishment [B4-B5] and end-of-life [C1-C4] stages. But there are resources that are cradle-to-site [A1-A4], cradle-to-end of construction [A1-A5], cradle-to-grave [A1-C4], or even cradle-to cradle [A1-D].
Normalisation
Targets alignment
Cost evaluation
Beyond LCA
Circular economy replaces the linear economy and is achieved through the application of principles: maintain, repair, reuse, re-manufacture and recycle, as well as leasing and servicing.
FAQ
What units are used for embodied carbon?
Embodied carbon is used as shorthand for Global Warming Potential (GWP). GWP is measured in carbon dioxide equivalents (kgCO2e). This unit converts all emissions that contribute to global warming, such as CH4, into CO2e by multiplying by their relative strength in producing warming.
What is this LCA good for?
LCA is valuable to inform early design decisions which aim to minimise the building’s whole life carbon impacts. A further assessment should be undertaken at practical completion, which should measure the as-built outcome, in place of modelled assumptions. LCA is most useful for relative, rather than absolute, comparisons. Ideally the analysis can be used for comparing design options, making material selections, and setting design priorities.
What is biogenic carbon?
Biogenic carbon is the process of carbon sequestration that takes place during the growth phase of bio-based materials, and is usually assigned during the cradle-to-gate impacts. Some LCAs account for these processes, others do not. If carbon sequestration is accounted for, it is best practice to account for the amount of this carbon that is released at end-of-life.
Best Practice
Design guidance
- Reuse existing building components (foundations, structural system)
- Minimize new building area by optimizing program
- Consider low carbon structural systems:
- CLT as floor slabs
- Glulam as beams, columns
- Rammed earth or bio-based bricks instead of concrete
- light gauge metal instead of structural steel
- Deploy lower-carbon materials:
- increase fly ash or slag content in concrete
- use FSC-certified wood
- increase recycled/salvaged content
- Optimize structural system (sizing of elements)
- Minimize impact of specific products
- compare product-specific EPDs