Running a fire flow analysis in EPS (Extended Period Simulation)

Applies To
Product(s): WaterGEMS, WaterCAD
Version(s): 08.11.XX.XX, 10.XX.XX.XX
Area: Modeling
Original Author: Mark Pachlhofer, Bentley Technical Support Group


Problem Description

How do you set up an EPS (Extended Period Simulation) scenario for fire flow that would run for a certain amount of time?


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 fireflow tool is steady-state 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. Quick start lesson #2 "Extended Period Simulation" (which can be found under Help > WaterGEMS Help > Contents > Quick Start Lessons) explains how to set this up.  

The screen shot 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.  


WaterGEMS "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.

Running a steady state fire flow at the peak conditions of an EPS

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)

See Also

EPS (Extended Period Simulation) Fire Flow Analysis Tool

Understanding Automated Fire Flow Results