Demand pattern for fire flow


I am attempting to model a 1-hour fire flow via EPS analysis. I have created a pattern in which the multiplier (flow) at a specific hydrant is zero up to 9AM. At this time, the multiplier switches to 1. Then at 10AM, I switch the multiplier back to zero to simulate the 1-hr fire. In the graph view of the pattern the multiplier jumps up to 1x at 9 AM in a segmented matter (aka does not gradually slope up) as it should.

However, when looking at the demand of the hydrant in an EPS graph, from 8 AM the demand constantly increases from zero until the actual imported demand value is reached at 9 AM (1x multiplier). Then, it follows the same slope in the negative direction until it reaches zero again at 10 AM, thus using the same amount of water as the 1-hr fire but essentially over a 2 hour period.

I understand that in the pattern creation tool I can set the multiplier to 0 at 8:59 AM so the demand jumps up to 1x right at 9 AM for an EPS analysis, but what is the more realistic scenario of the two? Or realistically does it stem from a combination of the two (i.e. demand gradually increases for 15 minutes until it reaches the required fire flow)?



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