This is Brad not Zach David. While we are waiting I just wanted to say I have been asking for 4 or 5 years here if someone will dig up an old certified pump curve and post the nameplate psi and rpm. I am 99.44% (like Ivory soap) sure I can tell you what the nameplate impeller diameter says. Are you game?
Brad On May 18, 2016 5:26 PM, "David Bitton" <[email protected]> wrote: > Hello Zach, > > > > In reviewing the various responses to this thread, I noticed that no one > actually answered your original question. Here's my attempt: > > > > The upper limit for the pump pressure rating can be estimated as follows: > > > > Nominal pressure = (175 psi - Y)/1.2 > > Y = Maximum suction pressure (static pressure if the pump is fed by > municipal mains) > > > > This formula is based on the following assumptions: > > 1. The maximum pressure rating for the piping and system > accessories is 175 psi. > > 2. The pump shut-off pressure is 120% of the pressure at the rated > flow (this can range from 100% to 140%, depending on the pump model). > > > > In addition, if the proposed pump will be driven by a diesel engine, the > nominal pressure derived from the above expression may be divided by 1.21. > The result would be the maximum pump pressure rating that would not require > the installation of a relief valve. > > > > *David Bitton, ing.* > > *Les services de prévention des sinistres Quest inc.* > > *Quest Loss Control Services Inc.* > > 5100, rue de la Savane, bureau 200 > > Montréal, QC H4P 1T8 > > (514) 341-4545 > > *www.questlosscontrol.com <http://www.questlosscontrol.com>* > > > > > > *From:* Sprinklerforum [mailto: > [email protected]] *On Behalf Of * > [email protected] > *Sent:* Wednesday, May 18, 2016 5:15 PM > *To:* [email protected] > *Subject:* RE: Equation for sizing fire pump > > > > In some jurisdictions you have to install an automatic suction control > valve to assure that you do not pull the municipal system lower than their > prescribed pressure. > > > > Typically the 20 psi flow point is provided on hydrant flow tests most of > the time by extrapolation. If you have that data then determining if the > pump will draw more than allowed is much simpler. > > > > > *Craig L. Prahl* > Fire Protection Group Lead/SME > *CH2M* > 200 Verdae Blvd. > Greenville, SC 29607 > Direct - 864.920.7540 > > Fax - 864.920.7129 > > CH2MHILL Extension 77540 > [email protected] > > > > *From:* Sprinklerforum [mailto: > [email protected]] *On Behalf Of *Zachary > Siegrist > *Sent:* Wednesday, May 18, 2016 5:07 PM > *To:* [email protected] > *Subject:* Re: Equation for sizing fire pump > > > > Yes, I was confusing sizing the pump with determining the max capacity for > the pump. Trying to avoid dropping below 20 psi which has been a problem > in my jurisdiction. Thank you Brad for your substantive reply. > On Wednesday, May 18, 2016, Brad Casterline <[email protected]> > wrote: > > Please brush up on NFPA 20. > > bc > > On May 18, 2016 2:48 PM, "Travis Mack, SET" <[email protected]> wrote: > > I think he is trying to get at the max capacity of a pump so that the > municipal water supply doesn't go below 20 psi. So, if his factor comes to > a max of 1200 and the system requires a 1500 gpm pump, then a tank is going > to be required. That is my assumption at least. > > Travis Mack, SET > > MFP Design, LLC > > 2508 E Lodgepole Drive > > Gilbert, AZ 85298 > > 480-505-9271 > > fax: 866-430-6107 > > email:[email protected] > > > > http://www.mfpdesign.com > > https://www.facebook.com/pages/MFP-Design-LLC/92218417692 > > Send large files to us via: https://www.hightail.com/u/MFPDesign > > LinkedIn: https://www.linkedin.com/in/travismack > > On 5/18/2016 12:46 PM, [email protected] wrote: > > Still not sure what that is supposed to represent or what you’re trying > to calculate. > > > > > *Craig L. Prahl* > Fire Protection Group Lead/SME > *CH2M* > 200 Verdae Blvd. > Greenville, SC 29607 > Direct - 864.920.7540 > > Fax - 864.920.7129 > > CH2MHILL Extension 77540 > [email protected] > > > > *From:* Sprinklerforum [ > mailto:[email protected]] *On Behalf Of *Zachary > Siegrist > *Sent:* Wednesday, May 18, 2016 3:42 PM > *To:* [email protected] > *Subject:* Re: Equation for sizing fire pump > > > > Sorry, I am looking at the wrong equation. That equation just ensures I > have 20 psi available at 159 percent. > > On Wednesday, May 18, 2016, <[email protected]> wrote: > > What are you supplying with your pump? > > > > I’m not seeing any correlation between a flow at 20 psi and sizing a > pump. What flow are you talking about, a municipal flow rate or what? > > > > If for sprinkler systems, you size the pump based on the characteristics > of the water supply and the system demands. > > > > There are ways to get an estimate on pump size but the final selection > better be verified through hydraulic calculations. > > > > > *Craig L. Prahl* > Fire Protection Group Lead/SME > *CH2M* > 200 Verdae Blvd. > Greenville, SC 29607 > Direct - 864.920.7540 > > Fax - 864.920.7129 > > CH2MHILL Extension 77540 > [email protected] > > > > *From:* Sprinklerforum [ > mailto:[email protected] > <[email protected]>] *On Behalf Of *Zachary > Siegrist > *Sent:* Wednesday, May 18, 2016 3:23 PM > *To:* [email protected] > *Subject:* Equation for sizing fire pump > > > > Is there an equation to specify an appropriate pressure when sizing a fire > pump? For example, when sizing gpm, I've always taken the GPM available at > 20 psi divided by 1.5 to give me the maximum GPM rating of the pump. I'm > inquiring to see if such a formula is available to size the pressure > correctly. Can anyone help? > > > > Zach Siegrist > > > > _______________________________________________ > > Sprinklerforum mailing list > > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > > > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > >
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