No such things as poorly worded or difficult positions here. The range of this Forum allows anyone to let their hair down and just blurt stuff out.,.,. even me :)
ps, you ar'nt by any chance looking at a pump nameplate right about now are you? Brad Casterline On May 18, 2016 5:55 PM, "Zachary Siegrist" <[email protected]> wrote: > It appears my question was poorly worded so it put y'all in a difficult > position to answer. Travis and David supplied the answer I needed. > Thank you all for your help. This has been informative. > > On Wednesday, May 18, 2016, Brad Casterline <[email protected]> > wrote: > >> 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]] *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 >>> >>> > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > >
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