Ron, Stay tuned...... the NFPA 13 Committee is dicussing this very item.. It appears that we would like to set the "buffer" or "safety factor" in order to establish consistent enforcement. We meet for the next two weeks to discuss this and much more.... I'm going to create an Academy blog that will be a streaming feed of how votes go in the Committee's discussions. Votes in Committee meetings are only a good indicator because there has to yet be an official ballot made. The meeting only requires a 50% voice vote to move a change to the ballot. But the balllot requires an affirmation of two-thirds.
It should be recognized that the above is my opinion as a member of the NFPA, and has not been processed as a formal interpretation in accordance with the NFPA Regulations Governing Committee Projects and should therefore not be considered, nor relied upon, as the official position of the the NFPA, nor any of their technical committees. Sincerely, Cecil Bilbo Academy of Fire Sprinkler Technology Champaign, IL 217.607.0325 www.sprinkleracademy.com [email protected] OUR STUDENTS SAVE LIVES!! > Date: Fri, 13 Jun 2014 13:01:36 -0700 > Subject: Re: Calculation Safety Factor > From: [email protected] > To: [email protected] > > The first interpretation but not for mere fluctuations. More that it's for > mathematically degrading systems due to higher anticipated demand (new > communities), or deterioration of the entire municipal system due to age > (older, established communities). And my understanding is it originated > with IRI and was to be applied to the water supply (downgrading the supply > by 10%), not the FP systems individually. As is often the case, when the > fire service gets married to an idea (like a single head in a kitchen being > a system) it perpetuates itself into the lore and the origins, and > concurrently, the rationale, are lost to the dim times of pre-history–don't > you get it? it's turtles all the way down. Since municipal raters and > underwriters could impose such a rule on a municipality, but the fire > service couldn't, the fire service shifted the burden to calculations of > the individual systems. Although the math for either method is a wash, how > does derating the system address the water supply itself? If the purveyor > derates voluntarily then the further derating of the system is overkill and > expensive, and if he doesn't the system derating is valueless. I think this > may be why NFPA never even mentions "safety margins" or "factors." I > realize I'm pretty much alone in this interpretation, and I'm not even 100% > sure of the origin of the "rule," but 10% degradation of the system > hydraulics, particularly with 5 year internal inspection intervals, just > makes no sense to me. > > > On Fri, Jun 13, 2014 at 12:22 PM, Rahe Loftin - 7PMC <[email protected]> > wrote: > > > I have always been under the impression that the safety factor indicated in > > specifications for hydraulic calculations was for water supply fluctuations > > in sprinkler systems connected to public water supplies. This is also > > indicated in the commentary in the NFPA 13 Handbook. > > > > However, recently a sprinkler contractor was contending that it was to > > allow for field piping changes. > > > > Any opinions? > > > > *Thanks* > > > > *Rahe Loftin, PE * > > _______________________________________________ > > 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 _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
