Eco-design approach based on the combination of life cycle analysis and sensitivity analysis: Case study on the life cycle of biosourced thermal insulation material, hemp concrete.

Summary The objective of this thesis is to establish an eco-design method based on Life Cycle Assessment, which should allow the identification of environmental action levers specific to each of the different economic actors involved in the life cycle of a product. The Life Cycle Assessment was coupled with two sensitivity analysis methods, following five steps described in the thesis: (i) the definition of the objectives and the system, (ii) the modeling of the calculation of the inventory and the impact indicators with differentiated approaches in the foreground and background, (iii) the characterization of the parameters used with a defined typology according to the possibilities of action of the economic actor concerned, (iv) the successive realization of two methods of sensitivity analysis (Morris and Sobol) on the defined model, (v) the interpretation of the results with a view to proposing effective avenues for improvement. The established approach was applied to the life cycle of hemp concrete, with the study of the stages of agricultural production, processing of hemp fibers and use of hemp concrete as thermal insulation in buildings. The approach allows to identify potential technological scenarios, allowing to improve the environmental performances, for each of the actors of the life cycle of the product. Implementing this approach currently requires additional information, but has a long-term gain as it allows to make robust choices for a given product.