Well, obviously the bogus flow test and I'll accept Mr Denhardt's comment without checking- he's WAY smarter than I am.
However- if the flow test was legitimate but they didn't knock off 10% - or BETTER- adjust for lowest tank gradient in its actual value- data is generally available from the water company for tank height during the flow test. If they didn't correct for tank gradient or toss a cushion at it (hey- where did the 10% come from when throwing in an allowance for tank gradient and future degradation???) then a <5PSI cushion is pretty slim. However, if the water is THAT bad, how do you give a 10 PSI cushion on a 35/3...@1500 flow test that can do the job with a 10% cushion after gradient correction? I know- with a fire pump. Cliff, when we go in prior to approvals and we're concerned in the least bit that we cut something too thin, I look to see where we can readily recover from it. Like throwing small crossmains on a tree, 2nd feed from a riser to a grid, etc. And Chris is right- it's never too late, just always more expensive than you didn't figure for. glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Craig Rauch Sent: Monday, November 30, 2009 3:50 PM To: [email protected] Subject: RE: Calcs-How much margin Please forgive the sidebar. What do you require for the adjustment required by 23.2.1.2 of NFPA 13 (2007) -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David Blackwell Sent: Monday, November 30, 2009 3:37 PM To: [email protected] Subject: RE: Calcs-How much margin As an AHJ we are in a similar position and would have to accept it if it met the absolute code minimum requirements. These are MINIMUM requirements. Many projects may need to be designed to a higher level than the legal minimum. That is why in SC the designer is required by State Law [See ยง40-10-250(B) at http://www.scstatehouse.gov/code/t40c010.htm] to be either a PE or [when exempt under the engineering law] a SC licensed sprinkler contractor with a NICET IV. It is the responsibility of the designer to account for reasonably foreseeable problems with the water supply capacity during the design life of the system. The designer will be the person in court being asked to justify their design choices if the system fails... The NFPA Handbook commentary to (2007) NFPA 13 23.1.2 [page 844] provides good information that should be read and carefully considered by the designer. David W. S. Blackwell, II, PE, CFI-I, CFPE Engineering ---------------------------------------------------------------- Office of State Fire Marshal 141 Monticello Trail Columbia, SC 29203 Phone: 803.896.9833 Fax: 803.896.9806 Email: [email protected] OSFM Website: http://www.llr.state.sc.us/firemarshal.asp ---------------------------------------------------------------- -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Richardson, R Sent: Monday, November 30, 2009 3:20 PM To: [email protected] Subject: RE: Calcs-How much margin I would not approve it based on the fact we have a local code requirement to have a 10 psi cushion. However, without that local code requirement it would definitely be approved. Without a local code requirement for a cushion there is no basis to not approve it. Rich Richardson Seattle Fire Department -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mike Hairfield Sent: Monday, November 30, 2009 12:17 To: AFSA SprinklerFORUM; Richardson, R Subject: RE: Calcs-How much margin I would approve it but ask for "As Built" Calcs!!!!! Mike > From: [email protected] > To: [email protected] > Date: Mon, 30 Nov 2009 14:15:07 -0600 > Subject: RE: Calcs-How much margin > > I would approve it. > I would also check the calculations VERY, VERY close. > > David Autry > Plans Examiner > Nebraska State Fire Marshal's Office > 246 S. 14th Street > Lincoln, NE 68508 > 402-471-9659 > 402-471-3118 fax > www.sfm.ne.gov > > ** Note new email address: [email protected] > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] > Sent: Monday, November 30, 2009 2:11 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) > _______________________________________________ > 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) _______________________________________________ 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) _______________________________________________ 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)
