All,
I'm a Civil Engineer and I've been tasked with creating a water model in EPANET for a proposed development that will have 7 different buildings to serve with culinary and fire flows. The seven buildings will be served by a looped waterline coming off a single connection to an existing water system.
The following scenario is simplified, of course, but it illustrates my question: Two of the buildings have 750 fixture units each. The remaining five have 1000 fixture units each. According to page 144 of the 2015 IPC, this yields peak daily flows of 177 gpm each for Bldgs 1 and 2 (assuming flushometer valves), and 208 gpm for each of Bldgs. 3 through 7, for a total of 2*177 + 5*208 = 1394 gpm culinary use. Since the entire development (all seven buildings) will be on the same waterline loop, we could also look at the total number of fixture units for the development (2*750 = 5*1000 = 6,500 fixture units). Although the chart on page 144 does not go higher than 5000 fixture units (=593 gpm), the Mechanical Engineer on the project has estimated that 6,500 fixture units corresponds to a flow rate of about 675 gpm. However, I'm not sure what percentage of this 675 gpm to assign in the water model to each remaining building for culinary flows during an assumed fire for one of the buildings. The Mechanical Engineer has said that this question is not in their expertise and refuses to give individual numbers that total 675 gpm.
I've entertained the pro-rating idea that, for instance, if Bldg 1 were on fire (it would be evacuating and would therefore not require culinary demand), then Bldg 2 should be assigned 675*(177/(177+5*208)) = 98.17 gpm, and the remaining five buildings would be assigned 675*(208/(177+5*208)) = 115.37 gpm. These numbers would add up to 98.17 + 5*115.37 = 675 gpm. Of course, the fire flows I model would be in addition to these flows.
While that approach seems reasonable to me, I don't think this question is within my expertise as a Civil Engineer. It seems to me that the Mechanical Engineer ought to be providing these individual numbers that add up to 675. Does anyone have any experience in assigning flow rates to individual buildings in a multi-building development such as this one. Also, does anyone have an opinion on which engineering discipline would typically address the question of divvying out the 675 gpm total culinary demand to each building in a water model? If we need to hire someone else, I just want to know who best to reach out to.
I'm a Civil Engineer and I've been tasked with creating a water model in EPANET for a proposed development that will have 7 different buildings to serve with culinary and fire flows. The seven buildings will be served by a looped waterline coming off a single connection to an existing water system.
The following scenario is simplified, of course, but it illustrates my question: Two of the buildings have 750 fixture units each. The remaining five have 1000 fixture units each. According to page 144 of the 2015 IPC, this yields peak daily flows of 177 gpm each for Bldgs 1 and 2 (assuming flushometer valves), and 208 gpm for each of Bldgs. 3 through 7, for a total of 2*177 + 5*208 = 1394 gpm culinary use. Since the entire development (all seven buildings) will be on the same waterline loop, we could also look at the total number of fixture units for the development (2*750 = 5*1000 = 6,500 fixture units). Although the chart on page 144 does not go higher than 5000 fixture units (=593 gpm), the Mechanical Engineer on the project has estimated that 6,500 fixture units corresponds to a flow rate of about 675 gpm. However, I'm not sure what percentage of this 675 gpm to assign in the water model to each remaining building for culinary flows during an assumed fire for one of the buildings. The Mechanical Engineer has said that this question is not in their expertise and refuses to give individual numbers that total 675 gpm.
I've entertained the pro-rating idea that, for instance, if Bldg 1 were on fire (it would be evacuating and would therefore not require culinary demand), then Bldg 2 should be assigned 675*(177/(177+5*208)) = 98.17 gpm, and the remaining five buildings would be assigned 675*(208/(177+5*208)) = 115.37 gpm. These numbers would add up to 98.17 + 5*115.37 = 675 gpm. Of course, the fire flows I model would be in addition to these flows.
While that approach seems reasonable to me, I don't think this question is within my expertise as a Civil Engineer. It seems to me that the Mechanical Engineer ought to be providing these individual numbers that add up to 675. Does anyone have any experience in assigning flow rates to individual buildings in a multi-building development such as this one. Also, does anyone have an opinion on which engineering discipline would typically address the question of divvying out the 675 gpm total culinary demand to each building in a water model? If we need to hire someone else, I just want to know who best to reach out to.
