Life Cycle Assessment (LCA) is a method for measuring the environmental impact of products, services and buildings and it is seeing huge momentum. LCA is a proven methodology for accounting for the environmental impacts of products or services in the built world over their entire life cycle. Framed by the international standard ISO 14040, LCA has been the subject of studies and scientific work for over 50 years. The primary objective of this calculation method is to assess the environmental impact of projects on the same basis throughout their life cycle.

The European climate package considers the greenhouse gas emissions of buildings at all stages of their existence from the origin of the materials used, to construction and the operational phase using a Life Cycle Assessment logic.  This approach is pioneering in Europe and opens a new circular economy as well as  eco-design perspectives.

To evaluate the environmental impact of buildings, in particular, the environmental impact of construction materials that make them up, product life cycle analysis is  necessary. This environmental data, when available, is accessible via dedicated databases such Inies (France), IBU (Germany), BRE (UK) EP Norge (Norway), etc.

The experiments carried out around the building LCA have led to establishing new indicators. They have made it possible to determine thresholds that serve as the founding layer of the new regulations. The sector actors were fully involved in writing the method and the definition of the thresholds of the regulation through consultations with the common objective of coupling construction and environmental concerns.

In France, the RE 2020 is characterized by the introduction of dynamic LCA in the calculation of building impacts and the evolution of the static LCA method. The latter remains the reference process for measuring the other environmental impacts since only the effect of global warming is calculated dynamically.

The proposed dynamic LCA is a calculation method adapted to the framework of the RE 2020, and which seeks to better consider the kinetics of degradation of greenhouse gases in the atmosphere. In this sense, the weighting introduced by the new regulation proposes a better approach of the chemical phenomena at stake. Consequently, it allows a better appreciation of the notion of the climate emergency and the uncertainty of end-of-life scenarios for materials.

The climate emergency

In the framework of the regulation, the consideration of the kinetics of degradation of greenhouse gases is translated by weighting the impacts on the climate according to the moment of the emission of the greenhouse gas. A kilo of CO2 equivalent greenhouse gas emitted during the construction of the building then penalizes more than the same kilo of gas emitted 20 years later.

Finally, since greenhouse gases remain in the atmosphere for many years, it is better to emit them as late as possible to reduce their total quantity and to stop global warming.

End-of-life scenarios for materials

There are uncertainties regarding the treatment of products at the end of their life. One of product LCA's challenges is to anticipate these different scenarios. The end-of-life scenarios currently developed use conventional and generally accepted statistical assumptions. For example, it is possible that out of the total quantity of product, 50% will be recycled, while 30% will be incinerated and 20% landfilled; this is what these scenarios describe.

For example, if a wooden frame is burned at the end of its life, it will significantly impact global warming than if it is recycled. But can we guarantee that the frame will be recycled instead of burned?

The weighting coefficients are identical for all materials, except for refrigerants. They are adapted to be able to make a dynamic LCA of a building with static LCA of product on a period of study of reference of 50 years.

Finally, this climate-conscious regulation is an opportunity to standardize and improve construction projects, CO2-emissions and, help to reduce the embodied carbon in the built world through a scientific approach. It positions Europe at the forefront of the climate-conscious transformation of the largest asset class in the world.

Decarbonising the built world is at the heart of what we do at A/O, therefore we have been backing innovative ClimateTech companies such as Vizcab (European leader in dynamic LCA), 011h (Eco-design built tech) SPAN (Climate-conscious home electrification technology).

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