The critical aspect of this type of interview is that the reliability of  data and the amount of information achieved are difficult to handle for many  reasons. First of all due to the variety of practice in question that can be  really different each other, making the process of generalization in some parts  very hard. Furthermore, since the sample population is not large enough, it is  possible to make considerations and determine trends only in relation to firms’  dimensions, flatten the peculiarity of the different type of firms. With  regards to the participation of AEC firms, probably it is discouraged by the  open-ended questions that if, on one hand, were opted with the intention to  affect as little as possible the answers, on the other, the fulfilment of the  questionnaire requires a lot of time and effort by the respondents. Moreover,  the outcomes depend on the role of the people interviewed and from their  competence in design process and especially in environmental issues. Finally, given  the specificity of some questions, the answers gathered risk to be  project-based, strictly related to one virtuous case with the connected  project’s location, type, dimensions and clients.

Life Cycle approach in design process

In order to stress a life cycle perspective during the research project  and the examination of AEC practice, a background activity has been developed  and is still ongoing with the aim to orient and streamline the design process  in line with environmental targets. The effort is to combine, on one hand, the  theory of the scientific community and, on the other, the practice of design  and construction firms (WP3 – descriptive phase).
As stated, due to the high impacts generated on the environment and the  strong international pressure of Sustainable Development Goals to be met by  2030, it is extremely compelling to appropriately change the attitude and way  of practice of building sector. In fact, to comply with the shared environmental  targets, it is crucial to dive and orient in the right direction construction sector  and the related built environment, to achieve great results in a limited time span.  The required environmental-oriented change represents a big challenge for the  construction sector, demanding an even more robust transformation process in a  sector still now considered resistant to change. Moreover, the change  management should embrace all the actors responsible for the built environment,  starting from the mindset to end with practical actions and operations. In this  context, two are the shared strategy that need to be applied. Firstly, the  implementation of Life Cycle Thinking to change the way of thinking within the  construction sector. Secondly, the application of LCA method to evaluate,  change and control the way of acting within design and construction practice.
However, to activate the type of mechanisms able to meet environmental  sustainability, it is not enough to identify the helpful methodologies, such as  LCT and LCA, but it is necessary to understand what are the actors involved and  how the methods can be integrated within the process. To this end, AEC firms,  including both architectural and engineering studios as well as construction  companies, represents the key actors responsible for the built environment. In  fact, constrained, on one hand, by regulations and standards and, on the other,  by clients and users’ requirements, they take most of the decisions that will  condition the building environment during the entire life cycle. Nevertheless,  despite the wide range of LCA tools and software available on the market to  help designers and practitioners in assessing environmental impacts and orienting  design choices, LCA analysis is not common in design and construction practice.  Moreover, when performed, it is mostly considered as a tool to demonstrate to  the clients the green-ness of the proposed solution, rather than as a tool to  compare alternatives and to support decision-making.
In this context, the research project seeks to combine the theoretical  level, represented by LCT and LCA, and the practical level, represented by AEC  firms. For this purpose, a conceptual framework was developed to match and  implement life cycle approach in design process, trying to figure out how it  can be employed according to the different phases of the process. The goal is  to enforce life cycle perspective in AEC practice starting from the early  stages of the project and to truly orient decision-making process in line with  environmental targets.
The basic matrix of the framework, shown in Figure \ref{634318}, is established, on  one hand (in the horizontal axis), by the different stages of LCA and, on the  other (in the vertical axis), by the different phases of design process. LCA  methodology and the connected stages and environmental information are analyzed  according to the European Standard “Assessment of environmental performance of  buildings” \citep{ENb} and Product Category  Rules “Buildings” \citep{PCR}. In  this way, the identification of LCA stages follows the typically classification  prescribed by the standards: product stage (A1-A3), construction stage (A4-A5),  use stage (B1-B7), end of life stage (C1-C4), benefits and loads beyond the  system boundary (D). Instead, design process phases are pointed out with  reference to the documents and reports produced by the United Nations  Environmental Programme “Greening the building supply chain” \citep{antink2014greening}, by the American Institute of  Architects “The architect’s handbook of professional practice” \citep{demkin2001architect} and by the Royal Institute of British  Architects “Plan of Work” \citep{sinclair2013riba}. In  this case, due to the different partitioning provided by the institutions, the  terminology was harmonized splitting the design process in five main phases:  concept phase, design phase, construction phases, in use phase and end of life  phase. Note that despite the similarity of the terms, the stage of LCA method do  not correspond to those of design process. Indeed, for example, the design  phase has to take into consideration all LCA stages, while the in use phase  should consider the LCA use stage but also the product stage with regards to  the maintenance and operational activities. To this end and in agreement with  the proposed framework, Figure \ref{634318} shows the LCA stages that can be addressed in  relation to each phase of the design process. The configuration of the matrix is not valid in absolute terms but may change based on the way of practice, depending  in particular on how deeply life cycle perspective is integrated in the design  process in object.