Hydrant and hose loss allowances) is what takes the time. Manually placing the fire demand is the easy part - iterating throughĭifferent flows to see if any nodes drop below 14.1m of head (20 psi) (plus Than manually placing a dummy fire demand at each node of interest. When investigating a larger system, it is more convenient to investigate theįire flow with a program that loops through each node automatically rather EPANET runs so quick though that it does not take long to run each alternative. This is several step process but seems to work well even with the large, county wide models we make. I also assign a required fire flow to see what effect that has on the system. I have also used this to calibrate a model based on hydrant flow test results.ĭepending on the model I double check the results by turning off all the reservoirs and assigning the flow calculated above to various nodes. Once it is adjusted the flow to the reservoir is the flow to the hydrant. When I run the model I tweak the reservoir elevations until the minimum system pressure is 20 psi at any given node. I obviously do not do this at all nodes, just at node that based on topography look like they may be problem spots or at areas where a new development may be going in (customer driven).įor the lines to the reservoirs I use 6 to 10 feet with 6' pipe and a minor loss to represent the hydrant nozzle.

I set it up so that only one pipe to a reservoir is open at a time. I then use the Rule-Based controls to open and close the pipe to the reservoir based on time. The reservoirs act as hydrants and are set with an elevation that produces 20 psi at the node. I method I have used is to place reservoirs at nodes of interest.

Water cad full tutorial