## 3 Development of the CEACE Method
### Characteristics of the Construction Projects  
In the CEACE tool, in addition to the project work units (ACCD coding) and their corresponding quantities, or Q\({}_{i}\), the input data includes other general data, such as typology, ground floor area (GFA), and number of floors above and below ground, see Figure 3. This tool generates the economic and environmental budget (according to the EF, CF, WF, and CDW indicators) per budget chapter and per work unit; a summary is presented per chapter, and the five work units that generate the greatest impact are identified, for each impact. All the outputs from the CEACE software are stored in Excel format. The information related to social aspects, such as the use of local labour and local materials, is also added to the Excel spreadsheet. Finally, an aggregated indicator is obtained that collects the triple information (economic, environmental, and social) and generates a sustainability indicator (I_CEACE) (Equation (1)). This level is the sum of the environmental (A), economic (E), and social (S) aspects, according to the weighting of 70% for environmental, and 15% each for economic and social aspects). The environmental aspects have been assigned the highest weight since this represents the main objective of the calculation method, although the method is versatile in the sense that the weights of each aspect can be changed according to the interests of the administrator. Other tools employ similar weighting procedures: the HADES tool [78] weights environmental aspects at approximately 60%, the economic part represents 17.4%, and the social aspects represent the remaining percentage, which include impacts on health and comfort, among others. VERDE [79] provides approximately 50% of the environmental characteristics, while the economic characteristics represent 17.4%, and the remaining portion corresponds to social aspects. In a similar way, in the recent work by [PERSON] et al. [95], indicators are weighted at 50% environmental; 30% social, and 20% economic. The calculation of the indicator is as follows:  
\[\text{I\_CEACE}=(\text{Au}\times\text{Ka})+(\text{Eu}\times\text{Ke})+(\text{ Su}\times\text{Ks}) \tag{1}\]  
where I_CEACE is the sustainability indicator; Au, Eu, and Su are the environmental, economic, and social coefficients, respectively. Ka is the environmental weighting factor (0.70), Ke is the economic weighting factor (0.15), and Ks is the social weighting factor (0.15). In order for the indicator, I_CEACE, to always have a value between 0 and 1 (that is, to be bounded), it is necessary that the three coefficients (Au, Eu, and Su) are also normalised between 0 and 1. For the normalisation of each of the coefficients, Equation (2) is used:  
\[\text{z}_{i}=(\text{x}_{i}-\text{min}(\text{x}))/(\text{max}(\text{x})-\text{ min}(\text{x})), \tag{2}\]  
where  
\(\text{z}_{i}\): \(\text{i}\) normalized value from the data  
\(\text{x}_{i}\): \(\text{i}\) actual value from the data  
\(\text{min}\) (x): minimum value in the data  
\(\text{max}\) (x): maximum value in the data  
This standardisation has been made possible thanks to the data obtained from the previous work of the researchers [47; 48; 34], relating to environmental and economic indicators, across a sample of approximately 100 projects. In order to obtain the coefficient Au, a standardisation process is conducted for each of the environmental indicators therein. Once the normalised values CFu, EFu, WFu, and CDWu have been obtained, Au (Equation (3)) is obtained:  
\[\text{Au}=(\text{CFu}\times\text{Kc})+(\text{EFu}\times\text{Ke})+(\text{WFu }\times\text{Kw})+(\text{CDWu}\times\text{Kcdw}), \tag{3}\]  
where CFu, EFu, WFu, and CDWu are the normalised unit values of each of the indicators obtained from the CEACE method. Kc, Ke, Kw, and Kcdw are the weight coefficients ofeach of the indicators, carbon, ecological, and water footprints and CDW, respectively. The four indicators are considered to be equally important. Therefore the weight of each is 0.25.