**4. Discussion**

The discussion of this chapter must start by framing the research questions presented at the beginning. Does the conventional LCA method need revision to change the paradigm? (i.e., achieving sustainability). The LCA method has been a research topic dating back to around 1997. As presented in previous sections, many variants and improvements to the LCA four phases can be found. Thus, rather than a revision


#### **Table 3.**

*Differences in the assessment outcomes of two building design alternatives when using different constituents for the assessment (using [4] as reference for other case studies).*

of the entire method is well-established, a broadening of its LCIA boundaries [4] and interpretation phase is needed. The former helps the designers to think beyond the "this product solves this specific problem and is better than the others" toward "this product is beneficial because it solves this specific problem, and no collateral impact is created at present nor in future scenarios." Here, the context is crucial [4], and thus, instead of letting the designer choose the impact assessment boundaries through its life cycle, it could reflect an advancement to the current variants of LCA.

However, encountered impact assessment tools still struggle to assess the achievement of sustainability of the product but assure advancement in the LCIA current indicators. Although the other two tools [15, 46] provide a quantitative framework for the LCIA, the Biocircular model [40] does not solely focus on providing a way of measuring sustainability but rather on working as a complement to the problem analyzed. This potential could be convenient to how LCIA is performed and interpreted in years to come, but the approach is in its early stages.

Hence, this brings us to our next research question. Could the biomimicry philosophy help improve the current LCA method? By highlighting the fundamentals and potential of the approaches encountered (Section 3), all three are based on biomimicry principles, including the cradle-to-cradle approach, which has its basis in a regenerative stage [7].

To demonstrate the application of the achieving sustainability assessment paradigm to the built environment, for instance, consider a net zero energy (NZE) design target for a new building and an existing building retrofitted toward the net zero target. **Table 3** provides an approach to assess both building designs following the current LCA and the new paradigm. This is done only for the usage phase among the building life cycle but considers all three aspects of sustainability.

Other examples can be also assessed, for instance, positive energy buildings. In this case, the surplus is exported to provide and share with nearby buildings. Another


#### **Table 4.**

*Differences in the assessment outcomes of a sustainable construction design project when using different constituents for the assessment (taking [40] as reference).*

#### *Including Nature-Based Success Measurement Criteria in the Life Cycle Assessment DOI: http://dx.doi.org/10.5772/intechopen.110401*

example is sustainable construction projects. **Table 4** presents an example of the binary orientation applied to the sustainable construction project under the "achieving sustainability" paradigm, taking as a reference the work of [40].

Moreover, a significant amount of quantitative and qualitative impact assessment indicators for sustainable construction projects are found in the literature. Such indicators can also be applicable to the impact assessment of other products or processes. However, it was noticed by [40] that none of the quantitative indicators have any limitations or threshold to offer a limit value that needs to be reached or passed in order to be considered as sustainable. Thinking about such limit value falls into the relative orientation of sustainability proposed by [55].
