I’d always used 20 psi as minimum pump in;et pressure, unless taking supply from a tank. Everywhere you go in AWWA you run into 20 psi as minimum pressure in the water system.
Best. Bruce Verhei > On 08/06/2020 2:54 PM Kyle.Montgomery via Sprinklerforum > <sprinklerforum@lists.firesprinkler.org> wrote: > > > These two options or the last pump test all should satisfactorily answer the > question. The "suction pressure" has nothing to do with the pump itself, just > the pressure that is available from the city source (or tank or whatever). As > mentioned, they generally need to know that so they can calculate the churn > pressure (city static plus pump shut-off pressure) to see if they need a > heavy-duty discharge flange or whatever. > > There's also the NPSH (net positive suction head). This is the pressure > available at max flow (generally 150% of the pump rating). The pump > manufacturer (and/or NFPA 20) will specify a minimum pressure for NPSH, > generally it just has to be greater than 0 psi. For systems that are > tank-fed, I think it can actually go slightly negative. Unless your water > supply is pretty weak, this generally isn't a concern. > > -Kyle M > > -----Original Message----- > From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On > Behalf Of Matt Grise via Sprinklerforum > Sent: Thursday, August 6, 2020 9:31 AM > To: sprinklerforum@lists.firesprinkler.org > Cc: Matt Grise <m...@afpsprink.com> > Subject: [EXTERNAL] RE: Pump Suction Pressure (NPSH) > > Or the reading on the pump inlet gauge. > > Matt > > > -----Original Message----- > From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On > Behalf Of cliff--- via Sprinklerforum > Sent: Thursday, August 06, 2020 11:29 AM > To: sprinklerforum@lists.firesprinkler.org > Cc: cl...@fire-design.com > Subject: RE: Pump Suction Pressure (NPSH) > > Brian, > > I may be looking at this too 'simply', but wouldn't your suction pressure be > the static pressure at the flow test location plus or minus any pressure gain > or loss for any difference between the elevation of the flow test and the > fire pump suction? > > Cliff Whitfield, SET > President > > Fire Design, Inc. > 600 W. Bypass Hwy. 19E > Suite 202 > Burnsville, NC 28714 > Ph: 828-284-4772 > > > > -----Original Message----- > From: Sprinklerforum <sprinklerforum-boun...@lists.firesprinkler.org> On > Behalf Of Brian Harris via Sprinklerforum > Sent: Thursday, August 6, 2020 11:24 AM > To: sprinklerforum@lists.firesprinkler.org > Cc: Brian Harris <bhar...@bvssystemsinc.com> > Subject: Pump Suction Pressure (NPSH) > > We're replacing a pump in an existing system and the pump vendor wants to > know the pump suction pressure. Since we didn't do the original system and I > know nothing about it what is a practical way of determining the pump suction > to tell the vendor? > > Brian Harris, CET > BVS Systems Inc. > Design Manager > https://urldefense.proofpoint.com/v2/url?u=https-3A__linkprotect.cudasvc.com_url-3Fa-3Dhttps-253a-252f-252fbvssystemsinc.com-26c-3DE-2C1-2CfPKVA9LmYVAFj6wU2zue-2Dsxj1lKPEyBR0IzSMOfmWQhkdfzW0pVPQNqdtRfwfotu1CJ1r199FT-5FxVT4xdVMuvik2UUqvDIqIumxKh1EZuYxd1ikkKAbfTUIf9RSb-26typo-3D1&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=qrvz34VqEnlqvCdkmUpKsl2fSFM_OJkuZgaRc2cBzOw&e= > > <https://urldefense.proofpoint.com/v2/url?u=https-3A__linkprotect.cudasvc.com_url-3Fa-3Dhttp-253a-252f-252fbvssystemsinc.com-252f-26c-3DE-2C1-2CbuGdxXghfmUtVg6sHK2xTuUeKegVK0ZTWUvIptb0cI1LRrHver5QaPWaFb9uOQnA-5FGerOgJLvt8a2uOixgbFnkz0LjRyO5XGG8r3gs94H7zXGOWoVwhXz8dHpg-2C-2C-26typo-3D1&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=f4e8BwlWb9f_RN4OzrXz-_MNT3xQi7kRZ_aDv40HWso&e= > > > Phone: 704.896.9989 > Fax: 704.896.1935 > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > https://urldefense.proofpoint.com/v2/url?u=https-3A__linkprotect.cudasvc.com_url-3Fa-3Dhttp-253a-252f-252flists.firesprinkler.org-252flistinfo.cgi-252fsprinklerforum-2Dfiresprinkler.org-26c-3DE-2C1-2C2XVMi2XSjpSC7MmxwbU-2Dge6SgOeyVoED5yFk21X5XiqzrUzFct2caDe-5FkBj1TqAbrNNIk2M5SL45K0rQhTUXHHqepHh5ofHFNfzY7x7CGz1mmtI5dRvA6adSKXqI-26typo-3D1&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=MB2xa5aCJYXTRgbB-bUTIYfbCy5Aww9K6WGtd5VhcWw&e= > > > > -- > This email has been checked for viruses by Avast antivirus software. > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.avast.com_antivirus&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=F7SBf5LjABLPB5Ki8fG9Y389eRwhoILV_en5NBZh2-I&e= > > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > https://urldefense.proofpoint.com/v2/url?u=https-3A__linkprotect.cudasvc.com_url-3Fa-3Dhttp-253a-252f-252flists.firesprinkler.org-252flistinfo.cgi-252fsprinklerforum-2Dfiresprinkler.org-26c-3DE-2C1-2CuMbFsjP2z9AB49BH0INlualK0jXC3SU0BL-5F2Amex0iJQsHKld3qPCkPpeMLYyobzZ-5FIexI7TdTwTCYKY-2DZscqOautAyn9z9OWCFyp8GUB8C0P8tsTL4Mi6A-2C-26typo-3D1&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=clCouJ9o3Z1F47ZnL5yiJNDDJjMwGgSt59QK_jt_dLk&e= > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.firesprinkler.org_listinfo.cgi_sprinklerforum-2Dfiresprinkler.org&d=DwIFAw&c=wn3mZQLIuInh2ClcJ0_DIA&r=Z_2A85VL7AQzoqudh6uOyS3bn8etxB7nLN8OBJwQd9A&m=Ea3hr6KtNl4vVEflZH44Z2ve1CdhBchfjHnNmruZtOA&s=U3nMzsioCTHsr6eT3EoRazkyD9IqBOE8uqYZ5bjxbcM&e= > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@lists.firesprinkler.org > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list Sprinklerforum@lists.firesprinkler.org http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
