Principles
Because of its visual simplicity, scientific grounding and holistic scope, we use Doughnut Economics as an assessment framework. The Doughnut consists of a social foundation, to ensure that no one is left falling short on life’s essentials, and an ecological ceiling, to ensure that humanity does not collectively overshoot the planetary boundaries that protect Earth's life-supporting systems. The Doughnut Economics Action Lab has developed a set of principles to guide our own evolution and our choice of collaborators. We placed these principles at heart with the development of the building material impact tool. We’ve chosen to at least assess CO2, nitrogen, biodiversity, well-being, and affordability, as these indicators were valued as most important by stakeholders in the construction industry. These 5 impact categories are divided into two groups, social and ecological. Each category has one or more impact indicators.
We’ve performed meta analyses of hard and soft data points from nationally recognized bodies to use as input for the tool. NIBE, Stichting Nationale Koolstofmarkt (SNK), ASN Bank and TNO engaged in the project to help validate our data. The dataset was filled with existing data from NIBE and Holland Houtland and expanded to include new materials and new impact categories. In the absence of nationally recognized frameworks for specific materials, desk-research was used to ascertain which data source is most appropriate, also considering EU (EN-norm based) data. All data sources were recorded and entered into the database for reference. The data of the building materials are stored and structured in this google sheet which is available for public use.
Stored Carbon
Stored carbon reflects the total CO2 equivalent that remains stored in bio-based materials on site after construction. It remains stored (out of the atmosphere) for as long as the building stands and the material exists.
Sequestered Carbon
Carbon taken out of the atmosphere by biological or technological processes. Once a reasonable duration of storage is expected (IPCC standards prescribe 100 years or more), sequestered carbon can be considered stored.
Life Cycle CO2
The Life Cycle Carbon dioxide embodied carbon dioxide reflects the total CO2 equivalent emitted from cradle to gate. This data is included in the Life Cycle Assessment (LCA) of each individual product. Many analysts use the term embodied carbon, however this is becoming increasingly confusing as actual carbon storage is considered, because ‘embodied’ sounds like the carbon that is in the actual ‘body’ of the material.
Embodied Carbon
Now increasingly confusing term used by LCA analysts to describe all energy and other emissions that went into the production of a product or material. See ‘Life Cycle CO2’.
Nitrogen Transport Emissions
The nitrogen emissions for each material are based on the total weight of the material and the distance travelled.
Biodiversity Impact
Biodiversity impact is measured in kg 1,4 dichlorobenzene (1,4-DB) eq. This is based on the ReCipe approach developed by RIVM, but is a lighter implementation due to data gaps across materials databases. Indicators used are land toxicity, freshwater toxicity and saltwater toxicity. Data is obtained from product LCA's.
Wellbeing
In this case we consider wellbeing as a psychosocial indicator based on consumer preferences towards climate positive goods and services. Empirical evidence indicates that practices linked to reducing the environmental impact are compatible with high levels of wellbeing. A positive score is given when negative carbon emissions for the whole house are reached.
Affordability
Alternative building materials come at a higher monetary cost than traditional materials due to market demand and scalability. Due to the fluctuation of building material prices per project we have omitted affordability as an impact category in this version. Initial research suggests that alternative building materials carry a premium of around 8% above average.
