Did he write his own hydraulics program and make you match his results? We have one of those. Perhaps we should introduce them.
At 05:03 PM 11/30/2009, you wrote: >Some day maybe I'll see if I can cut and paste what a PE around here >required. I haven't been able to figure it out, it was easier to not bid >their work. I do know it had nice things like: > >No field-installed offsets without revised calcs submitted and approved. >(Know how well that works with virtually any schedule?) > >Adjust C factors to like 85 for dry black steel, 100 for wet steel- cause >evidently the rest of us don't know jack. > >A description of how to knock 10, 15, 20% from the flowtest that leaves me >(and others here) scratching our heads on how to actually do what they ask >(as in 15% of what- flow? Pressure? Static? Residual? Everything?) > >Plus after adjusting the C factors, you can no longer discuss the cushion >with anyone else (insur AHJ, local AHJ) intelligently since the c-factors >are set more appropriately to a more conservative setting (we'd call it FULL >ANAL RETENTIVE) in case the pipe ages quicker than we expect. > >glc > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of Matt Grise >Sent: Monday, November 30, 2009 4:04 PM >To: '[email protected]' >Subject: RE: Calcs-How much margin > >I have to agree that all questions of water supply aside, 8.3.4.1 seems >pretty clear that k4.2 sprinks cannot be used in anything except light >hazard occupancy. > >Supposing they had used the proper heads...I would reject on the basis that >they tested a water main that does not feed the building. It seems like they >may have just fudged the placement a little in order to suggest that they >probably might have water similar to what was tested. > >Supposing they had the right heads and had tested the right line...I would >approve. Especially if they have knocked 10% off already. The reason that >there is a cut-off is because you have to be able to say yes or no at some >point. Obviously more safety is more better, but we can't all drive around >in tanks wearing football helmets. > >My understanding is that the 10% number is just one that was picked out of >thin air as something that people are generally ok with. I see specs call >for 10% psi, or 10psi, or 20 (both ways). There are some jurisdictions >around here that tried to push 30% for a while. > >Matt Grisé PE*, LEED AP >Sales Engineer >Alliance Fire Protection >*Licensed in KS & MO > >913.888.0647 ph >913.888.0618 f >913.927.0222 cell >www. AFPsprink.com > > >-----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) 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)
