How do you set up an EPS (Extended Period Simulation) scenario for fire flow that would run for a certain amount of time?
Or, how can you compare automated fireflow results to a manual EPS check?
In some cases you may want to see the impact of the duration of a fire event, such as how long it will take to drain storage tanks. The traditional automated fire flow tool is a steady state run only, so you must manually set up an EPS simulation that uses a pattern to peak the demand at whichever hydrants or junctions you'd like to run the fire flow on.
The screenshot below shows how you might set your pattern up of you were running a 3 hour fire flow at 2,000 L/min from hours 18-20 from your simulation start time.
The automated fire flow analysis calculates the water that can be delivered to a node for fire fighting at one point in time (steady state). Therefore, an extended period simulation (EPS) does not apply and cannot be run with this tool.
By setting the calculation option "Is EPS Snapshot" to True, the fire flow analysis will consider the starting date and time and apply the appropriate pattern multipliers for that time. However, this is still a steady-state analysis.
If you are running an Extended Period Simulation (EPS) with a demand set on a hydrant or junction that is equal to the available fireflow observed from an automated fireflow run, results can be different due to:
In some cases, a standard check would be to look at a range of fire flows and the resulting pressures, at the worst-case time during an EPS. For this, you can use the new "EPS Fire Analysis" tool available for the CONNECT Edition:
Fire flow analysis at the time of minimum pressure (EPS Fire Flow Analysis Tool)
EPS (Extended Period Simulation) Fire Flow Analysis Tool
Understanding Automated Fire Flow Results
WaterGEMS and WaterCAD Automated Fire Flow FAQ