## 5 Case Study
### Drinking-Water System Calculation
#### 5.1.2 Drinking-Water System Calculation--Case Study 2  
The second case study represents a real project, previously designed and with values calculated using the traditional methods described in Section 3.1 and approved by the DDWSS local administration. The building is structured over two floors and contains six retail stores inside the building and a garden area of 20 m\({}^{2}\). Each store has a water sub-meter fed from a general water meter. In addition, it has a 200 L/min wet fire suppression network. This project belongs to the category \"commercial or office premises\", so its occupancy is measured in terms of its surface area. Figure 9 shows the 3D model of the project, which is based on interpretation of the CAD drawings. Table 11 summarises the global data for the project. The architecture was designed with two different retail store patterns: those on the second floor have one less fixture than those on the first floor. Therefore, two different cases were considered for the study, choosing the stores on each floor that are farthest from the drinking water meter, as these are the most unfavourable in terms of friction losses due to the greater length of their pipes. Retail store type 1 has a toilet, sink, dishwasher and rain bath, while retail store type 2 has a toilet, sink and dishwasher. Figure 10 shows the systems for each of the types of stores used for the study. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Building Type** & **Subtype** & **Number of** **Occupants** & **Garden or** **Lawn Surface** & **Recirculating** **Pool Volume** & **Pool Volume** & **Firefighting Network** \\ \hline Commercial or office premises & Occupancy by surface area & 321.5 m\({}^{2}\) & 20 m\({}^{2}\) & 0 & 0 & 200 Lt/Min \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Global data for the retail store building case study. Figure 10: Sanitary plumbing water systems for the retail stores under study: (**a**) type 1 (first floor); (**b**) type 2 (second floor). Figure 9: Sanitary plumbing network layout for retail stores and offices. As in the case of the single-family house, the information corresponding to the general characteristics of the building is incorporated into a chart (Figure 11). With the information from the architectural model, scripts 1 and 2 are executed in Dynamo to obtain the nodes and sections of each system present in the structure, assign names to them (scripts 3 and 4) and determine the critical path. Figure 12 shows the results of the identification of the nodes and systems within the structure. As in the first case, the information is inserted into the MS Excel(r) spreadsheet. The results for the second case study are presented as follows. The general table of installed loads in the system is shown in Table 12, and the calculation memory of the drinking water meter that feeds the entire system is shown in Table 13.  
Figure 11: Project information chart for a retail building. Figure 12: Results of the application of scripts 3 and 4: (**a**) identification of nodes with the assignment of letters; (**b**) recognition of the drinking-water network system. The flow rate table corresponding to the type 2 store in the retail store project is shown in Table 18.  
As previously, the resulting values for the installed flow rates were correctly obtained, counting the fixtures with cold and hot water. In this case, a lower value for the total flow is evident due to the lower number of fixtures in this system. The result for the corresponding sub-meter is shown in Table 19. The table of losses for the type 2 retail store is shown in Table 20.