*4.2. Applicability Example*

The proposed procedure helps the operators in understanding the reliability of a network in terms of demand and pressure at a different level of the users' aggregation using hourly meter data. It can be adopted for understanding if peak values are changed with respect to the ones considered at the design stage, for planning DMAs and for verifying the behavior of existing networks in case of problems in the branched pipes where a lower number of household is served.

As noted above, Equation (15) tends to an asymptotic value as the number of households increases (*N* > 100–200). This means that for looped networks, which serve more than about 600 inhabitants, the peak value can be considered equal to the asymptotic value. Conversely, when considering a single mainline serving different small groups of households, the variability of the peak factor should be accounted for. The synthetic following example shows an application of the proposed formulation in verifying a branched pipe serving different groups of households. Figure 10 shows the main line with six nodes and Table 3 reports the number of households (each represented by a water meter) assumed connected to each node, and the corresponding number of users under the assumption that each meter serves 2.9 inhabitants.

**Figure 10.** Sketch of a schematic mainline with six nodes serving different groups of households.


**Table 3.** Example data.

For a total number of 180 served households, equivalent to 522 users, Equation (15) provides a peak factor (*CP*) equal to 1.60, which is the value that should be considered for designing the pipe L1. Indeed, while link L1 serves 180 households, L6 serves only three of them. Assuming a water supply of 0.07 L/s per inhabitant, Table 3 reports, for each link, the peak value obtained by means of Equation (15), μ*Nu* , as well as the corresponding mean, *Qm*, and peak, *Qp*, discharge. A correct evaluation of the hourly peak factor is important for designing the trunks of branch pipes, where an underestimation of the discharge may produce situations of pressure deficit. Conversely, an overestimation of the pipe diameter may produce low velocity and an increase of the water age with a consequent decay of water quality [50]. Concluding, the performed study highlights that the peak factor changes drastically in the interval 1 < *N* < 100, and this change has to be carefully considered for a correct design of branch pipes.
