EPANET++ is a free web application for modeling water distribution networks, an extension of EPANET.
Criticality analysis
Each asset is taken out of the network in turn, and the network is solved at the time step on screen in the active scenario. Nothing in the project is changed; the whole run is made on a copy.
When the project has an extended-period simulation, Reporting step tested can be set to The whole run. Each outage is then simulated over the full run, and the table reports the lowest pressure and the reporting step at which it occurs, the hours any junction spends below the lowest pressure allowed, the reporting step at which a tank first empties, and the largest demand not served over the run. Lowest pressures are read only before a tank empties.
All pipes, pumps, and valves, or only those selected on the map. Choose the set before you run.
- What each case does
For each link in the scope, the link is made inactive on a copy of the network, and the copy is solved at the time step on screen in the open scenario. A run is one solve for each link and one more with nothing broken. A junction left with no open path to a reservoir or tank is cut off: it is removed before the solve, and its demand is counted as Demand not served. Of the junctions still connected, Junctions below minimum lists those whose pressure falls below the Lowest pressure allowed. A junction that is already below it with nothing broken is not counted against any link, and the summary states how many there are. Lowest pressure allowed is the same setting as the Lowest system pressure allowed box of the Fire flow analysis.
- Dead ends, and the list
A dead-end link is one whose removal cuts off junctions that can be reached only through it. Everything beyond it is its loss, so with Skip dead ends checked the link is not solved, and the summary states how many were skipped. The list shows, for each link, the Demand not served, the Junctions cut off, and the Junctions below minimum, each with the number and the first five IDs, and a click on an ID goes to it on the map. Links that cost the system something are listed first until a column heading is clicked to sort, and the summary counts them against the number of links tested. Choose Selected links to break only the links selected on the map.
- Example on Net1
Open the Net1 example, choose Water, Analyze, Criticality analysis…, enter 116 for Lowest pressure allowed, and click Run. The time step is 0:00, and the run solves the whole network 14 times. Four of the 13 links drop a junction below 116 psi when they are out: L9 (N10, N11, and N21), L10 (N11 and N21), L111 (N21 and N22), and L112 (N21 and N22). Two junctions are already below 116 psi with nothing broken and are not counted. Because Net1 is looped, losing one link never leaves a junction without supply.