You say there is an underground loop. Therefore at some point in the underground supply the flow splits and then recombines before the demand. This is modeled as a single equivalent underground section. If the loop has some isolation valves, then it would be prudent to check both cases where the underground flow cannot split in its travel to the demand. There are three supply conditions to be aware of. If might be that a minimal system design change can accommodate the worst underground supply condition. One ought to be aware of a reasonable foreseeable condition.
> >> On May 6, 2024 at 8:38 PM, <Bob Knight <mailto:b...@firebyknight.com>> wrote: >> >> As a follow up to this, I ran the calcs both with an adjusted pressure and >> by creating the fictitious underground. >> The made up underground with the fire pump as the source created a lower >> overall demand. >> So, I'm more comfortable using the adjusted water pressure for the calcs. >> When a final set of utility plans is made available the calcs will be >> adjusted accordingly. At this point I like the idea of going with the more >> stringent of the two ideas. >> >> I appreciate all the help, and thanks Todd for pointing out the obvious fact >> that I missed about the static pressure. >> >> Thank you, >> Bob Knight, CET III >> Fire by Knight, LLC >> 208-318-3057 >> <FBK-LOGO-EMAIL.jpg> >> On 5/6/2024 3:18 PM, Fpdcdesign wrote: >>> There is no friction loss at 0 gpm. The static at the riser will be your >>> churn pressure plus the elevation gain. >>> >>> In my opinion, you should include the mains as you describe them as part of >>> the calculation. >>> >>> Todd Williams >>> Fire Protection Design/Consulting >>> Stonington, CT >>> 860-608-4559 >>> >>> >>>> On May 6, 2024 at 4:57 PM, <Bob Knight <mailto:b...@firebyknight.com>> >>>> wrote: >>>> >>>> I have a project where the complete underground plan has not been >>>> provided, yet. >>>> What I do have is a fire pump house with a recent fire pump test. >>>> The fire pump house is about 2,100 feet from the project site. It is >>>> elevated about 54 feet higher as well. >>>> I do have the underground loop around the building, so I was going to use >>>> the connection point at the loop for the underground from the pump house >>>> as the source point. >>>> The pump test shows 152 psi @ 0 gpm and 101 psi @ 1500 gpm. >>>> The elevation gain in pressure is 23.38 psi. >>>> The friction loss through the 2,100 feet of pipe and 16 or so fittings and >>>> valves, totals 2,372 feet. >>>> This came out to 21.24 psi of friction loss, assuming 800 gpm of flow >>>> including 250 gpm hose. >>>> I'm adding the elevation gain and subtracting the friction loss from the >>>> pump test. >>>> This leaves me with 154.14 psi @ 0 gpm and 103.14 psi @ 1500 gpm. >>>> I'm just going to use the numbers from the pump test and re-verify >>>> everything at a future date. >>>> Does this sound reasonable? >>>> >>>> -- >>>> >>>> Thank you, >>>> Bob Knight, CET III >>>> Fire by Knight, LLC >>>> 208-318-3057 >>>> >>>> >>>> >>>> <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >>>> Virus-free.www.avg.com >>>> <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> >>>> >>>> <x-msg://1/#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>_________________________________________________________ >>>> SprinklerForum mailing list: >>>> https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org >>>> >>>> <https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org> >>>> To unsubscribe send an email to >>>> sprinklerforum-le...@lists.firesprinkler.org >>>> <mailto:sprinklerforum-le...@lists.firesprinkler.org> >>> >>> _________________________________________________________ >>> SprinklerForum mailing list: >>> https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org >>> <https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org> >>> To unsubscribe send an email to >>> sprinklerforum-le...@lists.firesprinkler.org >>> <mailto:sprinklerforum-le...@lists.firesprinkler.org> >> _________________________________________________________ SprinklerForum >> mailing list: >> https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org >> To unsubscribe send an email to sprinklerforum-le...@lists.firesprinkler.org > <FBK-LOGO-EMAIL.jpg> > _________________________________________________________ > SprinklerForum mailing list: > https://lists.firesprinkler.org/list/sprinklerforum.lists.firesprinkler.org > To unsubscribe send an email to sprinklerforum-le...@lists.firesprinkler.org
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