Now does that mean all three or the requisite two? I believe you stated the third was a back-up should one or the other of the primary pumps be down for service.
On Fri, Mar 27, 2015 at 9:47 AM, Travis Mack <[email protected]> wrote: > We did just get directed to the following section from NFPA 20, 2010 > edition that explicitly addresses this: > > 14.2.5.2.3.1 Where simultaneous operation of multiple pumps is possible or > required as part of a system design, the acceptance test shall include a > flow test of all pumps operating simultaneously. > > So, it looks like the EOR will be looking to re-design a few of the > components. > > 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 > > On 3/26/2015 1:32 PM, [email protected] wrote: > >> With 3 pumps, 2 needed and one backup the suction and discharge header >> should be sized for 2 pumps. 16" pipe would result in a suction velocity of >> less than 10 fps, I believe that is the recommended limit in NFPA 20. All >> common pipe subject to the full flow of two pumps should be sized >> accordingly. >> Ron F >> >> -----Original Message----- >> From: Sprinklerforum [mailto:[email protected]. >> org] On Behalf Of Travis Mack >> Sent: Thursday, March 26, 2015 12:25 PM >> To: [email protected] >> Subject: Large pumping capacity >> >> I am working on a project where there is a fairly large demand. The EOR >> has determined there are to be (3) 3000 gpm pumps. These are all installed >> parallel. One of the pumps is to be a backup pump. The design has not been >> finalized, but the system demand (overhead sprinklers and grate foam >> nozzles) is somewhere around 6000 gpm. That is why we have two 3000 gpm >> pumps in parallel to create a 6000 gpm pumping capacity. >> There were some errors in the EOR pump room design that led to a few >> other questions. We are getting conflicting information from the EOR and >> the pump guys. The arrangement is that the pumps share a common suction >> header and a common discharge header. >> >> Per NFPA 20, a 3000 gpm pump needs a 12" discharge. The EOR showed 10" >> discharge piping and equipment, so this is what flagged some questions >> with the pump room design. The questions are now: >> >> 1 - Should the test header be sized to accommodate a 6000 gpm pump, or a >> 3000 gpm pump? The pump guy says that the common discharge header must >> be sized for the combined pumping capacity. The EOR states that it is only >> based on 1 pump flowing. I seem to agree with the pump guy, in that you >> need to test with both pumps flowing so you can test your water supply as >> well to show you can get the full 150% flow from the water supply. It is >> easy to size the piping so that the recommended velocities in NFPA 20 are >> not exceeded. It is just a question as to what is the basis. >> >> 2 - Should the common discharge header that the pumps tie in to be sized >> based on 3000 gpm pump or 6000 gpm pump? I believe that the common piping >> (after the pump discharge valve) only needs to be sized based on hydraulic >> calculations. >> >> 3 - These are diesel pumps. The individual relief valves are tied into a >> common discharge header. How should this be sized? Based on 3000 or >> 6000 gpm pumps? >> >> We are awaiting input from the authority having jurisdiction as well on >> this topic. The biggest issue is the pump test header and relief valve >> discharge piping. There are more issues of now trying to fit 12" >> valves/pipe/fittings on the discharge side of a pump in a room that was >> tight to begin with and was designed for 10" discharge equipment. >> >> Part of the issue is that NFPA 20 only goes to 5000 gpm tables for sizing >> pump room piping/equipment. The EOR is stating that the NICET tech is to >> correct anything in the pump room and provide it per NFPA 20. However, >> since we have a 6000 gpm total capacity, it is not possible to size things >> based on the summary table in NFPA 20 if it is to be based on 6000 gpm. >> >> I am just interested as to the thoughts of the guys on this forum. >> >> -- >> 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 >> >> _______________________________________________ >> 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 > -- Ron Greenman Instructor Fire Protection Engineering Technology Bates Technical College 1101 So. Yakima Ave. Tacoma, WA 98405 [email protected] http://www.bates.ctc.edu/fireprotection/ 253.680.7346 253.576.9700 (cell) Member: ASEE, SFPE, ASCET, NFPA, AFSA, NFSA, AFAA, NIBS, WSAFM, WFC, WFSC They are happy men whose natures sort with their vocations. -Francis Bacon, essayist, philosopher, and statesman (1561-1626) A problem well stated is a problem half solved. -Charles F. Kettering, inventor and engineer (1876-1958) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
