## 5 Methodology
### Call for Tenders Phase: Environmental Award Criteria within IMM and BIM Approaches  
GPP and IMM methodologies are considered as key aspects to introduce and integrate sustainable practices in AECO industry. This sub-section describes the innovative approach to the call for tenders phase, aiming to evaluate and compare the bids according to their environmental impact, and regarding the aspects of CDW minimization and management, and selective demolition procedures. The adopted tender process type is the Design Build (DB) model, in which a single operator is selected to conduct the final design and construction. The presence of a unique actor for the two stages eases a more efficient information transfer with the Client and a more collaborative process, which also ensures an easier management of the procurement and construction processes for the Client [84]. As a consequence, the DB model represents a valuable framework for the application of IMM approaches [85]. In addition, if the construction company realizes the final design, company characteristics and standard procedures can be taken into account. As a result, the final design can be optimized according to the capabilities and characteristics of the company itself. The call for tenders process based on the DB model implies the MEAT evaluation system introduced by D.Lgs. 50/2016, as recalled by Section 2.1. The evaluation of the bids is based on objective alpha-numerical criteria. The assessment of the quality of the bids is based on the rankings on the defined criteria (Table 3), thus promoting the automation of  
Figure 5: General scheme for waste management during the design phase within a BIM approach. the evaluation process. The environmental criteria considered in this research concerned the following sustainability aspects [86]:  
* Selective Demolition Procedures Criteria: procedures that should be defined according to the waste audit and digital material inventory;
* Demolition Waste Management Criteria: considering demolition materials as defined by the waste audit. It was necessary to define recyclable demolition waste by at least 70%, a mandatory requirement introduced by CAM (Section 2.2). The digital material inventory represents a fundamental annex of the tender documents for the identification of demolition materials and waste;
* Recommended Authorized Recycling Plants: minimizing the distance from the construction site and the carbon emissions from waste transport according to the analyses of the waste audit and the digital material inventory;
* Construction Materials and Waste Management Criteria: their quantities, characteristics, level of recyclability or reusability to achieve recyclable construction materials by at least 70%, a mandatory requirement introduced by CAM (Section 2.2);
* Construction Technical Solutions and CDW Management: on-site reuse strategies for demolition waste materials according to the BIM-based analyses;
* Construction Technical Solutions: procedures to increase the levels of durability, maintainability, safety for construction, and to decrease the waste generation. Throughout the entire process, waste minimization paired with the definition of safe and efficient selective demolition procedures is promoted with the highest rankings. Respecting the environmental criteria when presenting the bids would have provided additional points to the ranking of the companies, thus increasing their possibility of winning the call for tenders, and, at the same time, promoting the application of sustainable practices among the participants. In particular, the call for tenders assigned 80 out of 100 points to the technical offer. Among them, 27 points regarded the environmental criteria (Table 3), covering more than 25% of total points. Moreover, environmental criteria were linked to safety aspects by the sub-criterion D.1.1, requesting the OHSAS 18001 certification of the construction company safety management processes (which has been replaced by International Standard ISO 45001 in 2018) [87; 88].