Life-cycle Assessment

A life-cycle assessment is a systematic analysis of the potential environmental impact and the energy consumption of products throughout their entire life-cycle. Before each analysis the system boundaries (e.g. from cradle to grave or cradle to gate) are defined because different boundaries are useful depending on the product and the objective of the analysis. The environmental impact is evaluated on the basis of the emissions and resource expenditures of a product or process.

Environmental Impact Indicators

EN 15804+A1, the standard behind Timber Computer's data, defines seven environmental impact indicators (1). To evaluate the environmental impact of a building Timber Computer focuses on the global warming potential (GWP).

  • Global warming potential [CO₂e]
  • Ozone depletion potential [CFC-11e]
  • Acidification potential of soil and water [SO₂e]
  • Eutrophication potential [PO₄³⁻e]
  • Tropospheric ozone formation [C₂H₄e]
  • Depletion of abiotic resources (elements) [Sbe]
  • Depletion of abiotic resources (fossil fuels) [MJ]

Life-cycle phases

The life-cycle of a building is divided into the phase of production (A1–A3), the construction process (A4–A5), the use phase (B1–B7), and the end of the life-cycle (C1–C4), from deconstruction or demolition through transport and waste processing to disposal (2). Module D lies beyond this life-cycle, outside the cradle-to-grave system boundary. As supplementary information, it shows the potential benefits and loads of reuse, recycling and energy recovery after deconstruction; it is reported separately and not added to the life-cycle total.

Cradle to Cradle Cradle to Grave Cradle to Gate Waste A1–A3 A4–A5 B1–B7 C1–C4 D RawMaterial BuildingMaterials Building Building End ofLife A1–A3 Production A4–A5 Construction & Transport B1–B7 Use C1–C4 Destruction D Benefits/Reuse, beyond the life cycle

Life-cycle emissions

The global warming potential (GWP) is one of the decisive environmental impacts for assessing the sustainability of a building component or entire building. The holistic consideration of the building component from production to recycling or reuse is the basis for the creation of closed material cycles in the construction industry. In phase A, carbon can be released as well as bound. In phases B and C, carbon is mostly released (CO₂). Module D shows potential credits beyond the life-cycle, usually as negative values: emissions avoided when recovered material or energy replaces primary material or fossil fuel (substitution). For timber, the credit comes mainly from energy recovery. Timber Computer's total does not include module D.

Cradle to Cradle Cradle to Grave Cradle to Gate Waste A1–A3 A4–A5 B1–B7 C1–C4 D grey emissions operative emissions + - RawMaterial BuildingMaterials Building Building End ofLife A1–A3 Production A4–A5 Construction & Transport B1–B7 Use C1–C4 Destruction D Benefits/Reuse, beyond the life cycle

The determination of complete ecological data through life-cycle assessments goes beyond the scope of usual competition entries and feasibility studies. The advanced design and the determination of structural components are the basis for a life cycle assessment. At the same time, the continuous comparison with LCA data provides an important basis for decision-making during the design phase. This complexity can only be solved by real-time tools that are integrated into a holistic planning software.

At the same time, apart from certifications such as DGNB or the federal QNG seal, there are as yet no binding LCA targets that a building design must meet, as there are for noise protection, for example. From 2028 for large new buildings and from 2030 for all, the EU requires their life-cycle global warming potential to be calculated and disclosed; limit values are to follow (3). That there are none yet is mainly due to the fact that studies conducted to date are not comparable and LCA parameters are also highly sensitive to factors such as storey, cubature or building physics. Therefore, target values can only be defined on the basis of reference buildings.

Timber Computer helps to define frameworks and target agreements for sustainable project developments at an early stage.

References

  1. Deutsches Institut für Normung. (2014). Nachhaltigkeit von Bauwerken – Umweltproduktdeklarationen – Grundregeln für die Produktkategorie Bauprodukte (DIN EN 15804:2014-07). Beuth Verlag.
  2. Deutsches Institut für Normung. (2012). Nachhaltigkeit von Bauwerken – Bewertung der umweltbezogenen Qualität von Gebäuden – Berechnungsmethode (DIN EN 15978:2012-10). Beuth Verlag.
  3. European Parliament & Council of the European Union. (2024). Directive (EU) 2024/1275 on the energy performance of buildings.
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