3.2.4. Scenario 3: Fire Flow

In Scenario 3, adding to the base scenario flow condition, fire flow demands are sequentially generated at each node. It is assumed that fire occurs once for each node, and the probability of fire outbreak is the same in all cases; therefore, the performance change according to Scenario 3 can be identified through the average of the measured changes according to the simulation of individual fire flows. The Ontario Ministry of the Environment and Climate Change (OMOECC) [37] estimated fire flow demand according to the supply population of a WDN as shown in Table 2. Since the equivalent population of each node according to the base demand of the application network is approximately 1000, the fire flow demand at each node was applied as 230.4 m3/h. Table 3 presents a brief summary of each design condition, the base scenario and the three abnormal scenarios introduced above.


**Table 2.** Estimation of fire flow requirements (OMOECC [37]).

**Table 3.** Application scenarios comparison.


#### **4. Results**

#### *4.1. Correlation between Reliability Indices and Hydraulic Measures*

For 17 application networks, a total of 54 correlations were analyzed through the results of nine reliability indices calculated in the base scenario and the results of six hydraulic measures collected in Scenarios 1–3. As all reliability indices and hydraulic measures indicate that the higher the value, the more superior the reliability and performance of the network, it can be concluded that the larger the derived correlation coefficient, the better the index is at reflecting system performance.
