## 2 Materials and Methods  
The drafting of the certification protocol required a systematic and well-defined approach. The drafting process included the analysis of the relevant literature, the definition of the objectives and the selection of the necessary resources. In particular, the following steps were envisaged:  
STEP 1. Study of the structure of the certification system protocols (LEED, BREEAM, DNGB, CASBEE, HQE, ITACA PROTOCOL);  
STEP 2. Study of the current legislation on the DNSH Principle (in particular analysis of Regulation 2020/852);  
STEP 3. Definition of the structure of the certification protocol;  
STEP 4. Assignment of scores. The following image illustrates the methodological path used to obtain the sustainable construction site certificate (see Figure 1). The certification protocol is structured through a series of prerequisites and requirements to which a weighted score has been assigned, deduced from the existing regulatory obligations regarding the DNSH principle and the current environmental legislation, as  
Figure 1: The methodological path illustrates how the method develops from an analysis of existing protocols and their gaps and DNSH principles, to then develop its own structure and proceed to verify the score after its application to a case study. If the score is too low, it is possible to apply prerequisites dictated by the protocol in order to increase the class achieved. well as from the indications provided by the guidelines on environmental management of the construction site [19] of the rating and certification systems. The choice of the themes adopted to structure the protocol is a direct consequence of the analysis of Regulation 2020/852, which defines six environmental objectives that have been included within the method and treated as if they were macro-categories to which the requirements themselves can be traced back. The method used to assign the scores derives from the study of state-of-the-art examples and the complexity of the individual themes covered, and it assigns a higher score to the macro-categories with greater value and a lower score to the macro-categories with less importance for the specific area of the construction site. The complexity of the construction site activities did not allow for the evaluation of each individual aspect of the aforementioned environmental objectives in a meticulous and analytical manner; However, it is possible to summarise the salient aspects of the protocol:  
* Prerequisites that must be met;
* Requirements;
* Guidelines and instructions on how to carry out the work that determines the requirement score;
* Limits and parameters to be met;
* Pollution control and monitoring systems on the construction site. Each of these prerequisites are related to each of the DNSH criteria, previously mentioned and reported in Figure 2 below. The table analyses the reference legislation for each objective and the documentation necessary to obtain the coherence score. Figure 2: Main features of the certification protocol: objectives, reference legislation for prerequisites and requirements, definition of prerequisites and requirements for each environmental objective and definition of the necessary reference documentation. The final objective of the protocol is not so much to determine how impactful the construction site activity is or the level of pollution of the work carried out within it, but rather to propose improved solutions and ways of operating that, if respected, allow not only compliance with the DNSH principle and therefore fitting into a broader discussion of incentives and tax deductions, but also to improve the relationship between the construction site and the surrounding environment, especially in cases where the latter is a historic centre or a protected natural site. The protocol also contains references to IoT technology [20; 21] for monitoring the construction site, in particular to sensors for controlling the environmental parameters of confined spaces and the oscillations of scaffolding for the safety of workers.