The water supply could be useless. Is it connected to the main that does service the property? Is that calc done back to that? If not, I'd reject based on that alone.
At 03:22 PM 11/30/2009, you wrote: >They already took the 10% off the available pressures so their >actual margin would be around 10-11 psi without the 10% >decrease, but here's another twist, the test hydrant is not on the >same water main that serves the site and is several hundred to a >thousand feet away. So there is some question as to the real value >of the test in relation to what is actually available at the >site. Calcs say test to riser is less than 10ft. > > >Craig L. Prahl, CET >Fire Protection Specialist >Mechanical Department >CH2MHILL >Lockwood Greene >1500 International Drive >PO Box 491, Spartanburg, SC 29304-0491 >Direct - 864.599.4102 >Fax - 864.599.8439 >[email protected] >http://www.ch2m.com > > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of Steve Leyton >Sent: Monday, November 30, 2009 3:14 PM >To: [email protected] >Subject: RE: Calcs-How much margin > >Did they observe a safety margin below the actual flow test result? If >you take 10% off the available to start and still have 3.63 PSI, >then sure. But if that's 3.63 PSI below the actual flow test result >then unless the water supply is ... umm, distressed, it doesn't >sound like a good idea. > >Steve Leyton >Protection Design & Consulting >San Diego, CA > > > > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of >[email protected] >Sent: Monday, November 30, 2009 12:11 PM >To: [email protected] >Subject: Calcs-How much margin > >I've got a calc I'm reviewing, after all said and done, 3.63 psi >margin between demand and available. Designer used 4.2K heads to >get the flow exactly to the decimal of the required flow. This is >an industrial type project. With a .15 gpm/sf density at 92 sf per >head, the flow would be >13.8 gpm and he's dead on the money. The concern would be that over >the years if there was any change in the water supply or decay of >the piping, that the operation of half the design area would be questionable. > >Would you approve or reject this design? Is this cutting it just a bit close? > > > > >Craig L. Prahl, CET >Fire Protection Specialist >Mechanical Department >CH2MHILL >Lockwood Greene >1500 International Drive >PO Box 491, Spartanburg, SC 29304-0491 >Direct - 864.599.4102 >Fax - 864.599.8439 >[email protected] >http://www.ch2m.com > >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email >to:[email protected] >(Put the word unsubscribe in the subject field) > > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4650 (20091130) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com > > > >__________ Information from ESET NOD32 Antivirus, version of virus >signature database 4650 (20091130) __________ > >The message was checked by ESET NOD32 Antivirus. > >http://www.eset.com > >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email to:[email protected] >(Put the word unsubscribe in the subject field) >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email to:[email protected] >(Put the word unsubscribe in the subject field) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
